Substances and pharmaceutical compositions for the inhibition of glyoxalases and their use to combat cancer

FIELD OF THE INVENTION

The invention relates to compounds of the general formula (I) for the inhibition of glyoxalase I and/or II, pharmaceutical compositions comprising one or more compounds according to formula (I) , the use of one or more compounds according to formula (I) for the preparation of a medicament, and methods of treatment comprising the administration of one or more compounds according to formula (I) .

The compound of formula (I), pharmaceutical composition, medicament or method of treatment related to said compound of the invention are for the treatment of diseases associated with increased glycolytic metabolism, comprising diseases associated with one or more of: increased formation of oxo- aldehydes such as methylglyoxal , increased activity of glyoxalase I and/or II activity, and enhanced cell growth/proliferation. In one embodiment, the disease is cancer.

BACKGROUND OF THE INVENTION

Cancer is a disease in which cells originating from different organs (e.g. liver, brain, prostate, blood, kidney), are mutated by endogenous processes (errors in different processes during cell division) or exogenous factors (among others chemical mutagens, radiation) such that they are able to elude growth control, leave their tissue of origin and resettle in another organ after spread via the blood flow or lymphatic system and penetrate another organ (metastasis) . These cells can proliferate endlessly and form malignant tumors in the organ of origin as well as in an organ colonized secondarily, which can lead to the death of the affected.

Cancer can affect all tissues or organs of higher organisms, and occur at all stages of life, though there is a marked increase in cancer frequency with age. Some forms of cancer are relatively benignant, whereas others progress rapidly, metastasise early and lead to rapid death.

The diversity of their origin and the diversity of their formation renders all tumor cells generated unique. Tumors exist which are dependent on growth factors (e.g. EGF, PDGF, FGF, TGF, IGF, IL, CSF, EPO, NGF, INF, VEGF, HGF, BMP, leptin, and many others) or hormones (e.g. male or female sex hormones) or which produce autocrine stimuli. In many cases the growth stimulating factors are even unknown. Many recent approaches in the treatment of cancer aim at certain surface molecules, such as EGFR. However, the expression of such molecules is highly diverse between different cancers, and even amongst the cancer cells of a single individual.

As a result, an effective common therapy for the different kinds of cancer is not presently available. Moreover, conventional cancer therapies, such as chemotherapy, surgery or radiation are associated with severe side effects, and limited clinical efficacy. Most therapies are primarily life prolonging, but fall short of curing the disease. Because of these significant shortcomings of existing therapies, cancer remains a leading cause of premature death.

Therefore, there is a general need for the development of novel cancer therapies.

SUMMARY OF THE INVENTION

The problem underlying the invention thus resides in providing substances, compositions, medicaments and methods for the treatment of cancer.

Accordingly, the present invention provides compounds of the general formula (I)

wherein X is 0 or S; and

Rl is a branched or non-branched alkyl, cycloalkyl, branched or non-branched alkenyl, cycloalkenyl , branched or non- branched alkinyl , cycloalkinyl , alkoxyalkyl, alkoxycarbonylalkyl , aryl or a sugar residue; and

R2 is H or a branched or non-branched alkyl, cycloalkyl, branched or non-branched alkenyl, cycloalkenyl, branched or non-branched alkinyl, cycloalkinyl, alkoxyalkyl, alkoxycarbonylalkyl or aryl residue; and R3 and R4 together are =0, or R3 is OH and R4 is H; or R3 is H and R4 is OH.

In one embodiment, said substances are for inhibiting glyoxalase I and/or II.

One embodiment relates, to substances according to formula (I) , wherein Rl comprises 1 to 8 carbon atoms and R2 is H or comprises 1 to 8 carbon atoms. In a preferred embodiment Rl comprises 1 to 4 carbon atoms and R2 is H or comprises 1 to 4 carbon atoms.

In a further embodiment, the substance according to formula (I) is a substance wherein Rl and/or R2 is methyl, ethyl, propyl, isopropyl, butyl, or isobutyl. Particular embodiments according to the ^~ invention comprise one or more selected from methyl pyruvate, ethyl pyruvate, isopropyl pyruvate, butyl pyruvate, isobutyl pyruvate, ethyl 2- oxobutyrate, or the said pyruvate compounds according to formula (I) wherein X = S, as well as the compounds according to table 1.

The invention also relates to substances according to formula (I) , wherein in said substance R3 or R4 is OH and it is selected from the group comprising the D-, L- enantiomer, and the racemic mixture thereof, as exemplified in table 2.

The invention further relates to pharmaceutical compositions comprising one or more substances according to formula (I), the use of said substances for the manufacture of a medicament, and methods of treatment comprising the administration of said substances. The treatment with and/or administration of substances of the invention to a mammal, including humans, in need thereof, with a therapeutically effective amount of said substance is also encompassed by the present invention.

The invention further relates to the use of said substance, pharmaceutical composition, medicament or method of treatment in the treatment of a disease associated with increased glycolytic metabolism, comprising diseases associated with one or more of: increased formation of oxoaldehydes, such as methylglyoxal , increased activity of glyoxalase I and/or II activity, and enhanced cell growth/proliferation. In one embodiment, said disease is cancer.

In one embodiment, the pharmaceutical composition or medicament comprises one or more additional pharmaceutically active ingredients, comprising ingredients selected from chemotherapeutics , such as one or more selected from cyclophosphamide, doxorubicin, taxol , 5-fluorouracil or cisplatin. The pharmaceutical composition or medicament can further comprise one or more auxiliary substances, including, but not limited to, fillers, flavouring agents and stabilizers. The pharmaceutical composition or medicament of the invention can be prepared in the form of galenic formulations commonly known in the art, including sustained release or controlled release galenic formulation.

The pharmaceutical composition or medicament of the invention is for topic or systemic administration, more particularly, for oral, intravenous, intraarterial, subcutaneous, intramuscular, intradermal, intraperitonal , rectal, intranasal, epidural, percutanous, transdermal, pulmonary or intratumoral administration, or for administration as an aerosol, via mini-pumps, as mouth lavage, gel, plaster, and/or via microbubbles . The pharmaceutical composition or medicament can also be in the form of a food supplement and/or beverage supplement .

The pharmaceutical composition or medicament is for the treatment and/or prophylaxis of cancer in a mammal including human, wherein said cancer comprises malignant or benignant tumors, solid or non-solid tumors, or the ex-vivo purging of cancer cells. Optionally, the cancer is resistant to chemotherapeutic agents and/or radiation therapy.

More specifically, the cancer is one or more selected from carcinomas including breast, lung, bladder, thyroid gland, prostate, intestine, rectum, pancreas, stomach, liver, uterus, and ovary carcinomas; lymphomas including non- Hodgkin-Lymphoma, Hodgkin-Lymphoma, myeloma; leukemia including acute and chronic lymphoblastic leukemia, acute and chronic myeloblastic leukaemia; brain tumors including astrocytoma, glioma, medulloblastoma, glioblastoma, oligodenddroglioma, neuroblastoma; sarcomas including fibrosarcoma, liposarcoma, angiosarcoma, mesothelioma, chrondrosarcoma, osteosarcoma; and melanoma.

In one embodiment, the pharmaceutical composition or medicament is for the treatment of a mammal concomitantly suffering from an infectious disease, comprising bacterial, protozoal or fungal infections as well as worms, such as infectious diseases caused by one or more of Candida, Aspergillus, Cryptococcus , Zygomyces, Dermatophytes,

Blastomyces, Histoplasma, Coccidoides, Sporothrix, Trypanosoma, Leishmania, Plasmodium, Toxoplasma, helmithes, Acrobacter, Actinobacillus , Actinomyces, Bacteroides, Brucella, Clamydia, Clostridium, Campylobacter, Escherichia, Enterobacter, Enterococcus , Eubacterium, Fusobacterium,

Helicobacter, Hemophilus, Legionella, Listeria, Mycobacteria, Mycoplasma, Neissaria, Pasteurella, Peptostreptococcus , Pneumococcus , Pneumocystis, Porphyromonas , Prevotella, Pseudomonas, Salmonella, Shigella, Spirochetes, Staphylococcus, Streptococcus, Treponema, Vibrio, Yersinia, Escherichia coli or Pneumocystis carinii. Some of these infectious diseases may be an opportunistic infection, and/or may be characterized by antibiotic resistance.

In one embodiment the pharmaceutical composition or medicament is for use in a mammal having a reduced blood glucose level .

The invention further relates to the use of pharmaceutical compositions or medicaments of the invention in mammals that are going to receive, are currently receiving, or have received conventional cancer therapy, such as one or more of chemotherapy, surgery, radiotherapy or brachytherapy.

It is to be understood that all embodiments described in the context of pharmaceutical compositions or medicaments of the invention equally apply to methods of treatment, and vice versa. Thus, the mentioning of a particular embodiment in the context of one or more of a substance of the invention, pharmaceutical composition, medicament or method of treatment describes this embodiment for all remaining kinds of subject matter.

DETAILED DESCRIPTION OF THE INVENTION

A. Substances of the invention

In the context of this application, the terms "substances" or "compounds" are used interchangeably.

The present invention relates to compounds of the general formula (I) ,

wherein X is 0 or S, wherein Rl is a branched or non-branched alkyl, branched or non-branched alkenyl , branched or non-branched alkinyl , alkoxyalkyl, or alkoxycarbonylalkyl , each preferably with a chain length of Cl to ClO, more preferably Cl to C8 , more preferably Cl to C4 , in particular Cl, C2 , C3 or C4 ; or a cycloalkyl, cycloalkenyl , cycloalkinyl , aryl or a sugar residue, each preferably with a chain length of C3 to ClO, more preferably C3 to C8 , more preferably C3 , C4 , C5 or Cβ ; and R2 is H or a branched or non-branched alkyl, branched or non- branched alkenyl, branched or non-branched alkinyl, alkoxyalkyl, or alkoxycarbonylalkyl, each preferably with a chain length of Cl to ClO, more preferably Cl to C8, more preferably Cl to C4 , in particular Cl, C2 , C3 or C4 ; or a cycloalkyl, cycloalkenyl, cycloalkinyl or aryl residue, each preferably with a chain length of C3 to ClO, more preferably C3 to C8, more preferably C3 , C4 , C5 or C6 ; and R3 and R4 together are =0, or R3 is OH and R4 is H; or R3 is H and R4 is OH.

In one embodiment the sugar in position Rl is substituted or non-substituted sugar.

In one embodiment Rl comprises 1 to 4 carbon atoms and R2 is H or comprises 1 or 2 carbon atoms. In a further embodiment of the substance according to formula (I) , Rl and/or R2 is methyl, ethyl, propyl, isopropyl, butyl, or isobutyl.

In one embodiment R2 is H, and Rl is methyl, ethyl, propyl, isopropyl, butyl, or isobutyl.

Specific examples of compounds of the invention are listed in the following table 1, however, it is to be understood that this is not a limiting list. The skilled person can readily devise a large variety of additional compounds according to formula (I) :

Table 1: specific examples of compounds according to formula (D

Particular examples of substances according to formula (I) comprise methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, pentyl pyruvate, hexyl pyruvate, octyl pyruvate, isobutyl pyruvate, isopentyl pyruvate, isohexyl pyruvate, isoheptyl pyrvate, isooctyl pyruvate, cyclopentyl pyruvate, cyclopentylmethyl pyruvate, cyclohexyl pyruvate, cyclohexylmethyl pyruvate, butenyl pyruvate, hexenyl pyruvate, isobutenyl pyruvate, isohexenyl pyruvate, butinyl pyruvate, hexinyl pyruvate, methoxymethyl pyruvate, ethoxymethyl pyruvate, ethoxycarbonylmethyl pyruvate, methyl-2 -oxobutanoate, ethyl 2-oxobutanoate, butyl-2-oxo- butanoate, methyl-2 -oxopentanoate, ethyl-2-oxoheptanoate, butyl-2-oxopentanoate, methyl-2 -oxohexanoate, ethyl -2- oxohexanoate, butyl -2 -oxohexanoate, methyl -2 -oxoheptanoate, ethyl -2 -oxoheptanoate , butyl - 2 -oxo-heptanoate , isobutyl-2-oxobutanoate, isobutyl -2 -oxohexanoate, cyclohexyl- 2 -oxopentanoate, cyclohexylmethyl -2 -oxopentanoate, propyl-2- oxoheptenoate, cyclohexyl-2 -oxoheptenoate, butyl -2- oxoheptinoate, methoxymethyl-2 -oxopantanoate, ethoxycarbonylmethyl -2 -oxopentanoate , ethyl-4 -methoxycarbonyl - 2-oxobutanoate, ethyl -4 -methoxy-2 -oxobutanoate

or the said compounds wherein X = S, and/or the said compound wherein R3 or R4 is OH.

Preferred examples of substances of the invention comprise methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, pentyl pyruvate, hexyl pyruvate, isopropyl pyruvate, isobutyl pyruvate, isopentyl pyruvate, isohexyl pyruvate , methyl -2 -oxobutanoate , methyl -2 -oxopentanoate ,

ethyl-2-oxobutanoate, butyl-2-oxo-butanoate, ethyl-2- oxopentanoate cyclohexylmethyl pyruvate, or the said compounds wherein X = S, and/or the said compound wherein R3 or R4 is OH.

More preferred compounds of the invention comprise methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, isobutyl pyruvate, ethyl-2-oxobutanoate, ethyl -2- oxopantanoate, cyclohexylmethyl pyruvate, or the said compounds wherein X = S, and/or the said compound wherein R3 or R4 is OH.

Particularly preferred compounds are methyl pyruvate, ethyl pyruvate, butyl pyruvate, isobutyl pyruvate and ethyl-2-oxo- butyrate or the said compounds wherein X = S, in particular S-ethyl pyruvate, and/or the said compounds wherein R3 or R4 is -OH.

a) Substances according to formula (I) inhibit qlyoxalases Surprisingly it was found that the substances according to formula (I) inhibit glyoxalase I and/or II.

All living cells generate energy by the degradation of different food stuffs, and store it as chemical energy in energy rich compounds, particularly in the form of ATP. These energy rich compounds are subject to extensive turnover interconnected with anabolic and catabolic processes, by being used, for example, in the synthesis of proteins, nucleic acids, sugars, lipids etc., the transport of substances against concentration gradients and regulatory activities, and are formed anew in certain metabolic pathways. A plurality of compounds can serve as energy providing substances, the most important being sugars and fatty acids. After metabolising the different monosaccharides and their di-, oligo- and polymers extra- or intracellularly into corresponding derivatives, sugar degradation takes place in glycolysis. Glycolysis allows anaerobic as well as, in

combination with oxidative phosphorylation, aerobic energy- generation.

Glycolysis, however, is always accompanied by the formation of oxoaldehydes, in particular of methylglyoxal . These compounds are highly toxic as they easily form adducts with cellular proteins and nucleic acids and lead to their inactivation. Therefore, all cells using glycolysis employ detoxification systems, in most cases consisting of the enzymes glyoxalase I and II.

Both glyoxalases I and II are responsible for the degradation of the side product of glycolysis, methylglyoxal. Methylglyoxal is cytotoxic (e.g. by the formation of adducts with cellular proteins and nucleic acids) . Inhibition of the degradation of methylglyoxal leads to inhibition of cell proliferation and cell death by different mechanisms.

Thus, in one embodiment the substances according to formula (I) are for the inhibition of glyoxalase I and / or II, advantageously I and II. The inhibition of multiple enzymes drastically reduces the probability of developing resistance within the therapeutic period.

Surprisingly_ it was found that compounds of the present invention like e.g. ethyl pyruvate are capable of inhibiting glyoxalase I as well as glyoxalase II. Inhibition of glyoxalases by compounds of the present invention inhibits the cellular detoxification of methylglyoxal and via various mechanisms leads to the inhibition of cell proliferation.

Advantageously, compounds of the invention inhibit such cells showing a clearly increased rate of glycolysis whereas the metabolism of cells with a normal rate of glycolysis is not or only slightly affected.

Glyoxalase I (GLOl, alternatively abbreviated as GIy I,) is also known as (R) -S-lactoylglytythione methyl -glyoxal- lyase EC4.4.1.5), glyoxalase II (GLO2, alternatively abbreviated as GIy II) is also known as S-2-hydroxy-acylglutathione hydrolase (EC 3.1.2.6).

Glyoxalases are phylogenetically highly conserved at the amino acid and genetic level. As used herein, the term "glyoxalase" refers to the mammalian enzymes glyoxalase I and/or II, as well as to the respective glyoxalases of non- mammalian eukaryotic and prokaryotic organisms, such as glyoxalase I and II of yeast or other microorganisms.

Thus, the term "inhibiting glyoxalase I and/or II" encompasses the inhibition of the mammalian as well as the respective non-mammalian enzymes.

According to the invention, the substances according to formula (I) are for direct inhibition of glyoxalase I and/or II when R3 and R4 together are =0.

In contrast, when R3 or R4 are -OH, said substances according to formula (I) do not directly inhibit glyoxalase I and/or II. Rather, said substances, also called "prodrugs", are transformed, i.e. oxidized, to a substance wherein R3 and R4 together are =0.

Said transformation/oxidization can be effected ex vivo, e.g. by means of a chemical oxidant, such as potassium permanganate. Other suitable oxidants are for example hydrogen peroxide, iodine, iodide benzoic acid and others.

Alternatively, said transformation takes place in the organism, or on the skin or mucosa of the mammal upon administration of said compound. Such transformation is effected e.g. via dehydrogenases (in particular via lactate dehydrogenase) (Lluis and Bozal , 1976) .

Compounds of formula (I) , wherein R3 or R4 is -OH, and which undergo transformation such that R3 and R4 together are =0 are for example compounds of the general formula (II) and/or (III),

(H) (III)

wherein X, Rl and R2 are defined as in formula (I), above.

Specific compounds of the general formula (II) and/or (III) are for example methyl lactate, ethyl lactate, propyl lactate, butyl lactate, and ethyl-2-hydroxybutanoate, which are transformed into, e.g. butyl pyruvate, ethyl pyruvate, and ethyl-2-oxobutanoate, respectively,

When in a substance according to formula (I) R3 or R4 is OH, the invention encompasses the D-, L- enantiomer and the racemic mixture thereof. In the context of this invention, equimolar as well as non-eguimolar mixtures of corresponding enantiomers are to be considered as racemic mixtures.

In other words, in case the compounds of the invention are compounds with one or more chiral centres, for example ethyl lactate or butyl lactate, the corresponding D- and L- isomers can be used as well as racemic mixtures, for example ethyl D- lactate (DEL) , ethyl L-lactate (LEL) or racemic mixtures of DEL and LEL, and butyl D-lactate (DBL) , butyl L-lactate (LBL) or racemic mixtures of DBL and LBL, respectively.

Specific examples of compounds of the invention are listed in the following table 2, however, it is to be understood that this is not a limiting list. The skilled person can readily

devise a large variety of additional compounds according to formula (II/III) . The following table is understood to encompass the D- or L- Isomers or racemic mixtures of the listed substances. In other words, substances according to either formula II or formula III are specifically disclosed:

Table 2: specific compounds according to formula II / III:

Cyclopentyl H H / OH =0 Cyclopentylmethyl methyl lactate

Cyclopropyl H H / OH =0 Cyclopropyl lactate

Cyclopropyl H H / OH =0 Cyclopropylmethyl methyl lactate

Alkenyl

Vinyl H H / OH =0 Vinyl lactate

Allyl H H / OH =0 Propenyl lactate

Butenyl H ^■ -H / OH =0 Butenyl lactate

Pentenyl H H / OH =0 Pentenyl lactate

Hexenyl H H / OH =0 Hexenyl lactate

Heptenyl H H / OH =0 Heptenyl lactate

Octenyl H H / OH =0 Octenyl lactate

Branched Alkenyl

Isopropenyl H H / OH =0 Isopropenyl lactate

Isobutenyl H H / OH =0 Isobutenyl lactate

Isopentenyl H H / OH =0 Isopentenyl lactate

Isohexenyl H H / OH =0 Isohexenyl lactate

Isoheptenyl H H / OH =0 Isoheptenyl lactate

IsooctenyL H H / OH =0 Isooctenyl lactate

Cycloalkenyl

Cyc1ohexeny1 H H / OH =0 Cyclohexenyl lactate

Cyc1ohexenylmeth H H / OH =0 Cyclohexenylmethyl yi lactate

Cyclopentenyl H H / OH =0" ^' Cyclopentenyl lactate

Cyclopentenylmet H H / OH =0 Cyclopentenylmethyl hyl lactate

Alkinyl

Ethinyl H H / OH =0 Ethinyl lactate

Propinyl H H / OH =0 Propinyl lactate

Butinyl H H / OH =0 Butinyl lactate

Pentinyl H H / OH =0 Pentinyl lactate

Hexinyl H H / OH =0 Hexinyl lactate

Heptinyl H H / OH =0 Heptinyl lactate

Octinyl H H / OH =0 Octinyl lactate

Branched Alkinyl

Isopentinyl H H / OH =0 Isopentinyl lactate

Isohexinyl H H / OH =0 Isohexinyl lactate

Isoheptinyl H H / OH =0 Isoheptinyl lactate

Isooctinyl ^• H H / OH =0 Isooctinyl lactate

Cycloalkinyl

Cyclooctinyl H H / OH =0 Cyclooctinyl lactate

Alkoxyalkyl

Methoxymethyl H H / OH =0 Methoxymethyl lactate

Ethoxymethyl H H / OH =0 Ethoxymethyl lactate

Methoxyethyl H H / OH =0 Methoxyethyl lactate

Alkoxycarbonylal kyl

Methoxycarbonylm H H / OH =0 Methoxycarbonylmethyl ethyl lactate

Ethoxycarbonylme H H / OH =0 Ethoxycarbonylmethyl thyl lactate

Aryl

Phenyl H H / OH =0 Phenyl lactate

Naphthyl H H / OH =0 Naphthyl lactate

Sugar

Glucosyl H H / OH =0 Gucosyl lactate

Galactosyl H H / OH =0 Galactosyl lactate

Mannosyl H H / OH =0 Mannosyl lactate

Alkyl Alkyl

Methyl Methyl H / OH =0 Methyl 2- hydroxybutanoate

Ethyl Methyl H / OH =0 Ethyl 2- hydroxybutanoate

Propyl Methyl H / OH =0 Propyl 2 - hydroxybutanoate

Butyl Methyl H / OH =0 Butyl 2- hydroxybutanoate

Methyl Ethyl H / OH =0 Methyl 2- hydroxypentanoate

Ethyl Ethyl H / OH =0 Ethyl 2- hydroxypentanoate

Ethyl Ethyl H / OH =S S-Ethyl 2- hydrxypentanethionate

Propyl Ethyl H / OH =0 Propyl 2 - hydroxypentanoate

Butyl Ethyl H / OH =0 Butyl 2- hydroxypentanoate

Methyl Propyl H / OH =0 Methyl 2- hydroxyhexanoate

Ethyl Propyl H / OH =0 Ethyl 2- hydroxyhexanoate

Propyl Propyl H / OH =0 Propyl 2 - hydroxyhexanoate

Butyl Propyl H / OH =0 Butyl 2- hydroxyhexanoate

Methyl Butyl H / OH =0 Methyl 2- hydroxyheptanoate

Ethyl Butyl H / OH =0 Ethyl 2- hydroxyheptanoate

Propyl Butyl H / OH =0 Propyl 2- hydroxyheptanoate

Butyl Butyl H / OH =0 Butyl 2- hydroxyheptanoate

Branched Alkyl

Isobutyl Methyl H / OH =0 Isobutyl 2- hydroxybutanoate

Isobutyl Ethyl H / OH =0 Isobutyl 2- hydroxypentanoate

Isobutyl Propyl H / OH =0 Isobutyl 2- hydroxyhexanoate

Isobutyl Butyl H / OH =0 Isobutyl 2- hydroxyheptanoate

Cycloalkyl

Cyclohexyl Ethyl H / OH =0 Cyclohexyl 2- hydroxypentanoate

Cyclohexylmethyl Ethyl H / OH =0 Cyclohexylmethyl 2- hydroxypentanoate

The D- or L- enantiomers or the racemic mixtures thereof of the following substances are further particular examples of substances of the invention: methyl lactate, ethyl lactate, propyl lactate, butyl lactate, pentyl lactate, hexyl lactate, octyl lactate, isobutyl lactate, isopentyl lactate, isohexyl lactate, isoheptyl lactate, isooctyl lactate, cyclopentyl lactate, cyclopentylmethyl lactate, cyclohexyl lactate, cyclohexylmethyl lactate, butenyl lactate, hexenyl lactate, isobutenyl lactate, isohexenyl lactate, butinyl lactate, hexinyl lactate, methoxymethyl lactate, ethoxymethyl lactate, ethoxycarbonylmethyl -lactate, methyl -2 -hydroxybutanoate, ethyl 2 -hydroxybutanoate, butyl -2 -hydroxybutanoate, methyl -2- hydroxypentanoate, ethyl-2-hydroxyheptanoate, butyl-2- hydroxypentanoate, methyl-2 -hydroxyhexanoate, ethyl-2- hydroxyhexanoate , butyl -2 -hydroxyhexanoate , methyl -2 - hydroxyheptanoate, ethyl-2-hydroxyheptanoate, butyl-2- hydroxyheptanoate, isobutyl -2 -hydroxybutanoate, isobutyl-2- hydroxyhexanoate , cyclohexyl -2-hydroxypentanoate , cyclohexylmethyl -2 -hydroxypentanoate, propyl -2- hydroxyheptenoate, cyclohexyl-2-hydroxyheptenoate, butyl -2- hydroxyheptinoate , methoxymethyl -2 -hydroxypantanoate , ethoxycarbonylmethyl -2 -hydroxypentanoate , ethyl -4 -

methoxycarbonyl -2 -hydroxybutanoate , ethyl -4 -methoxy-2- hydroxybutanoate , or the said compounds, wherein X=S.

If ethyl lactate is used, ethyl L-lactate (LEL) as well as ethyl D-lactate (DEL) are effective. The effect of esters of D-lactate is surprising as D-lactate is considered to be non- metabolizable in mammalian cells (Murray et al . , 1993) and the same had to also be presumed for esters of D-lactate. Hence it could not have been expected that those compounds could be applied at all according to the invention and that they would exhibit such good effectiveness.

The inventors' own . measurements confirm the interconversion of ethyl lactate and ethyl pyruvate by NAD-dependent lactate dehydrogenases. Butyl lactate can, to a lesser degree than ethyl lactate, also be transformed by NAD-dependent lactate dehydrogenases. When butyl lactate is used according to the invention only cells with a particularly high activity of lactate dehydrogenase will reach therapeutically effective concentrations of butyl pyruvate.

Thus, compounds of the general formula (II) and (III) act as prodrugs, as exemplified in Examples 2 and 3.

Lactate and alky! lactate, respectively, are transported over the cell membrane by a lactate shuttle (monocarboxylate transporters (MCT's) ) (Garcia et al . , 1994; von Grumbckow et al . , 1999) in combination with a proton transporter. For the transport into mitochondria mitochondrial MCTs are available. Addition of lactate and its alkyl esters, respectively, to blood leads to slight alkalization due to the proton- connected lactate transporters whereas the application of pyruvate and its alkyl esters, respectively, leads to an acidosis of blood, caused by enzymatic ester cleavage.

Lactate and alkyl lactate are transported stereo selectively and better through the membrane as compared to pyruvate and

alkyl pyruvate (Roth and Brooks, 1990) . Alkyl pyruvates administered to blood have to be transformed into alkyl lactates before they can enter cells.

Moreover, the rate of hydrolysis of compounds according to formula (I) wherein R3 or R4 is -OH is lower as compared to compounds wherein R3 and R4 together are =0, leading to an improved in vivo stability.

In addition, it is a typical feature of cancer cells to have increased activity of lactate dehydrogenase, achieved mainly by specific induction of lactate dehydrogenase A in tumors (Lewis et al . , 2000). Therefore, the use of "prodVugs" of the invention, i.e. compounds according to formula (I) wherein R3 or R4 is -OH, such as butyl lactate leads to an increased selectivity of the proliferation inhibiting effect for cancer cells .

Therefore, it is advantageous to use compounds wherein R3 or R4 is -OH, and in particular, therapeutically active, physiologically compatible alkyl lactates.

In the context of this application, the compounds according to general formula (I), including direct glyoxalase inhibitors and their _^ prodrugs, and the specific examples of compounds, including the compounds according to formula (II) and (III), are also summarily referred to as "compounds of the invention" .

A particular advantage of the substances of the invention resides in the fact that toxicity of said substances and their metabolites is only very low (Clary et al . , 1998) . After saponification by esterases they are metabolized to equally non- or only slightly toxic alcohols and to carboxylic acids which are also produced in normal cell metabolism (e.g. pyruvate and lactate) . For example, the concentration of lactate in human blood is 2-20 mM. Lactate

is contained in many foods, is generated in metabolism and can be metabolised.

This also explains the low or even absent ecotoxicity of these compounds (Bowmer et al . , 1998) in tests with

Selenastrum capricornutum, Daphnia magna, Pimephales promelas and Brachydanio rerio. These compounds are also devoid of mutagenic potential in normal cells as demonstrated in an established test system (Andersen and Jensen, ^' 1984) .

b) The substances of formula (I) differ from known inhibitors of qlvoxalases

The inhibition of glyoxalases by compounds of the present invention has so far been unknown. _ .

On the basis of the substrate of glyoxalase I, the hemithioacetal of methylglyoxal and glutathione, peptidic glyoxalase inhibitors are widely described in the literature (Creighton et al, 2003; Hamilton & Creighton, 1992; Hamilton and Batist, 2004; Johansson et al . , 2000; Kalsi et al . , 2000; Kamiya et al , 2005; Ranganathan et al, 1995; Sharkey et al . , 2000; Thornalley, 1993; Thornalley et al, 1996; Thornalley, 1996; Vince and Daluge, 1970) .

US 4,898,870 describes pyrroloquinoline quinone compounds in the context of inhibition of glyoxalase I. WO 99/035128 also describes compounds for inhibition of glyoxalase I . WO 04/101506 describes a further class of non-peptidic inhibitors of glyoxalase I, as does Douglas et al, 1985;.

However, the glyoxalase inhibitors known so far exhibit a relatively high or very high toxicity and are metabolized to compounds which in turn have manifold pharmacological effects, some of which lead to severe side effects.

Furthermore, the glyoxalase inhibitors known so far only inhibit either glyoxalase I or glyoxalase II, respectively.

However, when inhibitors are directed to a single protein target only, resistance can develop very quickly, as for example mutations appear in the relevant protein, which make the inhibitor ineffective.

Therefore, the glyoxalase inhibitors of the present invention are advantageous over known inhibitors.

c) The known effects of substances according to formula (I) do not encompass qlvoxalase inhibition

From the known effect of methyl pyruvate its influence on glyoxalases was not predictable. For years methyl pyruvate has been intensely investigated as an insulinotropic compound (Dύfer et al . , 2002; Valverde et al . , 2001; Lembert et al . , 2001) . This effect is mediated by influencing potassium channels and mitochondrial effects. Inhibitory effects on LDH have also been proposed (Lluis, 1976) .

Furthermore, it has been described that the administration of ethyl pyruvate can improve inflammatory states, reperfusion injury, acute renal failure and ischemia (WO 03/088955; WO 02/074301; WO 01/024793, WO 05/044299, WO02/081020, US2003/232884) . In patent US2004/110833 ethyl pyruvate is used to influence cytokine mediated diseases. This is attributable to abolishing the effect of NF-kβ (Han et al . , 2005; Yang et al . , 2004; Fink et al . , 2004; Miyaji et al . , 2003; Ulloa et al . , 2002) . However, opposite observations also exist in this respect (Mulier et al . , 2005) .

However, by no means these mechanisms indicate an inhibition of glyoxalases. Moreover, they can not be used to explain an inhibition of cell growth, because according to the findings of the present invention the growth of yeast cells is also inhibited by ethyl pyruvate, which cells neither have NF-kβ nor cytokines nor other inflammatory mediators.

Additionally, it could be shown that protein adducts of methylglyoxal , the concentration of which is increased after inhibition of glyoxalases, even increase the release of TNF-a and the activation of NF-kβ (Fan et al . , 2003). In particular, this mechanism can not be used to explain the inhibitory effect of ethyl pyruvate on proliferation as the effect of ethyl pyruvate on cytokines is also detectable when cells are not proliferating.

The inhibitory effect of ethyl pyruvate on proliferation mediated via the inhibition of glyoxalases is the more surprising as ethyl pyruvate, due to its known effect as "scavenger" of reactive oxygen radicals should rather have a growth enhancing effect (Varma et al . , 1998) . As a matter of fact, this has been described for normal human T-lymphocytes (Dong et al . , 2005) . In this report it has furthermore been described that the formation of the cytokine interleukin-2 was enhanced in these cells.

B. Pharmaceutical composition/manufacture of a medicament/methods of treatment

The present invention relates to the medical use of compounds of the invention, their use for the preparation of medicaments, pharmaceutical compositions comprising said compounds and methods of treatment _^ comprising administering said compounds or compositions .

In the following, particular embodiments will be described in the context of pharmaceutical compositions. However, it is to be understood that these embodiments also apply to the medical use of compounds of the invention, the manufacture of a medicament, and a method of treatment. In other words, any disclosure of an embodiment in the context of a pharmaceutical composition is not to be understood as being limited thereto, but also relates to the manufacture of a medicament or a method of treatment. Thus, the terms "medical use of a compound of the invention" , "pharmaceutical

composition", "use for the manufacture of a medicament" and "method of treatment" in the context of this application are interchangeable. This applies to the entirety of the present application.

The basic embodiment of the invention is a pharmaceutical composition comprising at least one substance of the invention .

In one embodiment, the pharmaceutical composition of the invention comprises the substance according to the invention as the sole active ingredient. Thus, in one embodiment the combination of the substance of the present invention with a further active ingredient is excluded. This does not exclude the presence of more than one substance of the present invention. This does also not exclude the presence of non- pharmaceutiaclly active additives, i.e. substances which contribute to preparing a galenic formulation, such as fillers, flavouring agents, stabilizers, etc.

In one embodiment the pharmaceutical composition can comprise a combination of one or more compounds of the general formula (I) wherein R3 and R4 together are =0, e.g. ethyl pyruvate, and one or more compounds wherein R3 or R4 is -OH like compounds of the general formula (II) and (III), e.g. ethyl _ lactate, (ethyl D- and/or L-lactate) .

The pharmaceutical composition of the invention can further comprise one or more additional pharmaceutically active ingredients. In the context of combinations with further active ingredients the low toxicity of the compounds of the present invention as well as their metabolites is of particular advantage.

As further pharmaceutical compounds, preferably chemotherapeutics, immunosuppressive agents, common agents against worms and fungi, antibiotics, substances favoring

cell differentiation like transcription- and growth factors, inhibitors of glycolysis or substrates for glycolysis are used.

For example, a combination of a compound of the present invention, such as ethyl pyruvate with common chemotherapeutics in the context of a standard chemotherapy which generally exist for example for carcinomas and sarcomas can be used. Some representative examples of standard chemotherapeutic agents are cyclophosphamide and doxorubicin for the treatment of breast cancer and leukemia, taxol for the treatment of ovary cancer, and 5-fluorouracil or cisplatin for sarcoma.

A preferred combination consists of compounds of the present invention and an inhibitor of glycolysis wherein the inhibitor of glycolysis interferes with glycolysis downstream of the triosephosphate isomerase reaction. The rationale of such a combination is to increase the concentration of triosephosphates from which methylglyoxal evolves parametabolically or paracatalytically, and thus, to improve the efficacy of therapy.

Particularly preferred is the combination of compounds of the present invention, in particular ethyl pyruvate or the corresponding thioester, and oxamate, an inhibitor of lactate dehydrogenase. Also particularly preferred is the combination of compounds of the present invention and an inhibitor of the glycerol aldehyde phosphate dehydrogenase, such as iodide acetate, and/or the lactate dehydrogenase inhibitor oxamate.

In addition to the compounds according to the invention further compounds may be preferably applied which stimulate the metabolism of infectious organisms, such as bacteria, fungi or protozoa, like substrates of glycolysis, in particular glucose, or for example 2 , 4-dinitrophenol acting as uncoupler of the respiratory-chain. In this manner

advantageously the concentration of methylglyoxal is increased further and the efficacy of the compounds of the invention is increased further, resulting in an enhanced efficacy of the pharmaceutical composition.

The pharmaceutical composition can also be used for the treatment of cancer in combination with an agent stimulating tumor growth. Such provocation of fast tumor cell proliferation increases the rate of glycolysis of the tumor and thus, its sensitivity towards compounds of the present invention. Such stimulating agents are for example growth factors (EGF, PDGF, FGF, TGF, IGF, IL, CSF, EPO, NGF, INF, VEGF, HGF, BMP, leptin) and hormones (insulin, estrogens, androgens, thyroid hormones, adrenocorticoids , hypothalamic hormones, pituitary hormones), nicotine and others. The composition can advantageously be used in combination with the stimulant (growth factors, hormones, etc.) required by the different tumors. Thus, therapy with compounds of the present invention can be individualized to the respective tumor characteristics of an affected patient.

In case a tumor has been removed by surgery, cancer cells from the explanted tumor tissue can for example be cultured and it can be tested which agents (hormones, cytokines like TGF-β, medicaments and other chemicals) are able to stimulate the cancer cells. This can for example also be performed in combination with molecular biology methods wherein the expression of receptors is determined. Proliferation factors identified in this way can then be used for therapy in combination with the compounds of the present invention, e.g. ethyl pyruvate.

A further aspect of the invention is the use of compounds of the present invention in combination with known or novel genetic methods like siRNA and antisense nucleotides for the targeted inhibition of enzymes or proteins to increase the sensitivity of tumors (Nesterova and Cho-Chung, 2004) .

The pharmaceutical composition or medicament can further comprise one or more auxiliary substances useful for the galenic formulations of drugs, including, but not limited to, fillers, flavouring agents, stabilizers and antibiotic agents .

The pharmaceutical composition can be in any suitable galenic formulation, depending on the kind of disease to be treated and the chosen route of administration. The skilled person can readily select and prepare a suitable preparation on the basis of common general knowledge. Pharmaceutical compositions of the invention can be prepared according to known methods e.g. by mixing one or more effective substances with one or more carriers, and forming of e.g. tablets, capsules, or solutions. Where appropriate, solutions can be e.g. encapsulated in liposomes, microcapsules or other forms of containment .

Examples of suitable formulations comprise aqueous solutions which can optionally be buffered, water in oil emulsions, oil in water emulsions, creams, ointments and formulations comprising any of the foregoing.

The invention encompasses a pharmaceutical composition prepared in the form of a sustained release or controlled release galenic formulation. Such formulations allow the targeted release in e . g . a certain location, such as a certain part of the gut, or a certain tissue or organ, and/or allow the sustained release over a defined period of time.

A pharmaceutical preparation can also be prepared by mixing the ester components of the compounds of the invention under conditions at which compounds of the general formula (I) are formed. The pharmaceutical preparation can also be prepared by assembling ester components of the compounds of the invention such that in the organism, for example in the

acidic environment of the stomach, the compounds of the general formula (I), (II) or (III) are formed. Ester components are for example an alkanol like for example ethanol and an organic acid like for example lactic acid.

The pharmaceutical composition of the invention comprises at least one compound of the invention in a therapeutically effective amount. The skilled person can readily determine the therapeutically effective amount in standard in vitro or in vivo experiments. For example, the effective amount can be estimated on the basis of an extrapolation from in vitro data, such as enzyme inhibition or cellular assays.

For example a dosage can be formulated in animal models which corresponds to the IC50 in cell culture experiments. Hence, according to commonly known methods, the optimal dosage for the vertebrate to be treated, such as humans, can be deduced from animal experiments. The amount of the agent to be administered naturally depends on the person to be treated, his body weight, his genetic and physical constitution, the disease state, the route of administration, the galenic formulation and other parameters.

Furthermore, dosage and the interval of administration can be guided by the individual plasma concentrations of the agent that guarantee a therapeutic effect.

Useful effective concentrations, i.e. concentrations to be achieved at the level of cellular exposure, range from at least 0.05 mM, preferably from 0.05 mM to 50 mM, more preferably 1 mM to 40 mM, more preferably 1 mM to 20 mM, most preferably 1 mM, 2.5 mM, 5 mM, or 7,5 mM in systemic application. In topic applications higher concentrations may be useful. Preferred are 0.2 to 200 mM, more preferred are 0.2 to 50 mM and 50 to 200 mM.

In other words, the concentrations above refer to desired blood and/or tissue concentrations, or local concentrations. Thus, the invention relates to pharmaceutical preparations suitable to achieve such concentrations in vivo upon administration.

To achieve a therapeutic effect the pharmaceutical composition of the present invention is generally applied for several days or weeks as repeated bolus doses (e.g. injections) or continuous administration (e.g. infusion), or any time period required to achieve a therapeutic effect, at the respective therapeutically effective dosage.

The pharmaceutical composition of the present invention can be administered topically or systemically . In both topical and systemic administration a local administration to a selected site can be performed. Because of their nature, esters are of limited stability, necessitating the use of higher and/or repeated doses for systemic application. This can be circumvented by local application.

An example of local administration is intratumoral administration, preferably under stereotactic or ultrasound control, or e.g. via locally positioned probes in combination with pumps, or in case of superficially located tumors via creams or other means of local administration.

Pharmaceutical compositions comprising the compounds of the invention can be administered according to generally known methods - including but not limited to oral, intravenous, subcutaneous, intramuscular, intradermal, intraperitonal , rectal, intranasal, epidural, percutanous, or transdermal administration, or administration as an aerosol, via mini- pumps, as mouth lavage, gel, oil, ointment, cream, spray, plaster, via microbubbles and/or pulmonary application (e.g. by inhalation) .

Administration is for example systemic, e.g. by single or repeated oral or parenteral application, or via methods wherein the medicament is administered systemically in an inert vehicle and is only released at the desired location by respective manipulation. An example thereof is, amongst others, so called microbubbles as described in Bekeredjian et al. (2005) and Bekeredjian et al . (2003).

The pharmaceutical composition can also be a food supplement and/or beverage supplement. In the context of the present invention, "food supplement" or "beverage supplement" means a pharmaceutical composition that is administered together with the standard daily diet, or a special medical diet. It also means "health food", i.e. food of a particular composition that is consumed by subjects without medical supervision to achieve a prophylactic or therapeutic effect.

C. Medical indications

The substance, pharmaceutical composition, medicament or method of treatment of the present invention is for the following medical indications.

The invention encompasses the administration or use in a vertebrate animal, more particularly a mammal including humans, in need thereof.

In the context of this application, the term "animal" is meant to encompass vertebrate animals, comprising non- mammalian vertebrates and mammals, which mammals comprise man. Thus, the term animal encompasses humans.

In particular, the pharmaceutical composition is for a vertebrate animal, including man, suffering from a disease associated with increased glycolytic metabolism. Such diseases may further be associated with one or more selected from increased formation of methylglyoxal , increased activity of glyoxalase I and/or II and increased cellular growth

and/or proliferation. Preferably, the diseases associated with increased glycolytic metabolism are associated with enhanced methylglyoxal formation. Specific examples of such diseases include cancer, including the various specific types of cancer discussed below.

a) Cancer

It was surprisingly found that the compounds of the formula (I) can inhibit growth and/or proliferation of cancer cells. The substances can in addition kill cancer cells and/or induce senescence.

In the context of this application, "inducing senescence" means that cells acquire a more differentiated phenotype and loose their property to divide, and possibly undergo cell death.

Anti-cancer effects of substances of the invention have previously been unknown.

According to EP 0 717 984 and JP 8 208 422 proliferation of normal human cells, for example keratinocytes , is even stimulated by compounds of the present invention, which effect is used -to improve the appearance of the skin. Similarly, in, several .patents (US 5,580,902; US 4., 234,_599; US 4,105,783) compounds of the present invention have been described as agents to improve skin consistency and smoothen wrinkles. Effects on keratosis, and several diseases characterized by defective keratinisation (dandruff, acne, palmar and plantar hyperkeratosis, dry skin, Darier's disease, lichen simplex chronicus, psoriasis, eczema, pruritus, warts and herpes) are described in US 3,879,537, US 3,920,835, US 4, 246., 261 and US 7,33,815.

Moreover, ethyl lactate can be added to shampoos used in the treatment of canine superficial bacterial pyoderma (de Jaham, 2003) . Fungicidal effects have also been suggested for this

compound (US 2005/0020678) . Methyl pyruvate has been suggested to treat fish parasites (WO 02/102366) .

Ethyl pyruvate has been used to improve cataracts (Devamanoharan et al . , 1999). In this connection a lowering of dulcitol and glycated proteins by ethyl pyruvate has been found, connected to the effect of pyruvate formed by hydrolysis of ethyl pyruvate.

CN 1175632 describes ethyl lactate as an auxiliary substance in the manufacture of Spirulina wine, but does not disclose ethyl lactate as an active ingredient. WO 03/088955 and WO 02/074301 deal with the treatment of cachexia, a clinical symptom that is the sequel of cancer. However, these documents do not relate to the treatment of cancer per se. Marx et al , 1988 suggests the inhibition of cancer cells by lactate. The document fails, however, to disclose ester compounds of lactate. Similarly, Stanko et al, 1994, discusses a role of pyruvate in the treatment of cancer, but fails to disclose any pyruvate containing esters. Moreover, the data of Stanko et al, -1994 are difficult to interpret, as the authors themselves admit. Comparative tests on the effects of pyruvate on cancer cells performed by the present inventors clearly demonstrate that pyruvate does not inhibit, but even promotes cancer cell growth (see experiment 16) .

Though not intending to be bound by this hypothesis, it is suggested that the cancer inhibiting activity of the compounds of the invention is due to their inhibition of glyoxalase I and/or II.

Cancer cells require significant amounts of energy for cell division. In addition, cell division in many tumors occurs at reduced oxygen supply, because tumors are oftentimes poorly vascularized and solid tumors always show large areas of poor blood supply, which are hypoxic.

A general feature of tumors is a high rate of glycolysis in accordance with the hypoxic conditions, which proceeds even in areas of better vascularization as "aerobic glycolysis". This characteristic of cancer cells, which is also called "missing Pasteur effect" has already been described by

Warburg more than 70 years ago and has been confirmed many times since. It is only controversial if an increased rate of glycolysis has to be seen as a cause or consequence of transformation in tumorigenesis (Garber K., 2004).

US 2004/0167079 describes for example a method for treatment of cancer by use of 2-deoxyglucose (2-DG), an inhibitor of glycolysis .

US 2003/0181393 discloses the glycolysis inhibitors 2- deoxyglucose, oxamat and iodide-acetate. Iodide acetate inhibits glycerolaldehyde-3 -phosphate dehydrogenase and oxamate inhibits lactate dehydrogenase.

The main shortcoming of inhibiting glycolysis is that glycolysis is used for energy generation in almost all cells, such that healthy cells are also affected by inhibition of glycolysis. In particular the influence on the brain is dramatic as the brain is an obligatory consumer of glucose and thus is highly dependent on glycolysis.

A more recent approach to therapeutic intervention aiming at influencing the modified and increased glycolysis as a tumor- cell specific target is therefore no longer related to the inhibition of glycolysis, but to the inhibition of glyoxalases (Thornalley et al . , 1994; Vander Jagt et al . , 1990; Pemberton and Barrett, 1989; Creighton et al . , 2003; Hamilton & Batist, 2004) .

Cancer cells generally have a very high concentration of • glyoxalases to cope with the increased amount of methylglyoxal resulting from increased glycolysis. Under the

effect of glyoxalases, 2 -oxo-aldehydes like methyglyoxal are transformed into the corresponding 2 -hydroxy acids like D- lactate via the intermediate S-D-lactoyl-glutathione.

If degradation of methylglyoxal is prevented by glyoxalase inhibitors, cells, which due to increased glycolysis produce increased methylgyloxal , such as cancer cells, accumulate this cytotoxin. This leads to inhibition of their growth, senescence and apoptosis of the cells.

Thus, the inhibition of glycoxalases can serve as a "universal" therapy for a plurality of cancers.

The term "cancer" encompasses malignant and/or benignant tumors, and relates to solid and non-solid tumors. The terms "cancer" and "tumor" are understood to be interchangeable. Moreover, the terms "proliferation" and "growth" are used interchangeably .

The term "treatment" encompasses subjects suffering from any of the various disease stages, and encompasses after- treatment as well as prophylaxis.

"After-treatment" means a treatment following conventional therapy, such as radiation therapy, chemotherapy, surgery, etc. It is meant to encompass treatment following a completed conventional therapy (e.g. a full regimen of chemotherapy comprising several individual treatment periods, or following surgery) , and treatment that is intermittent with the conventional therapy, e.g. taking place in the intervals between individual courses of chemotherapy. It is also meant to relate to a therapy that is started after the conventional therapy (e.g. after the first course of chemotherapy) and then continues concomitantly with the first therapy (e.g. throughout the further courses of chemotherapy) .

The term "prophylaxis" or "chemo-preventivum" relates to administration of a pharmaceutical composition of the invention when a subject is at risk to develop a disease, or a disease is suspected or is present subclinically, but said disease has not fully evolved or has not been diagnosed.

The term "treating cancer" in the stricter sense relates to the treatment of clinically manifest disease. It is meant to encompass both cytotoxic and cytostatic effects. Thus, "inhibition of cancer cells" encompasses the inhibition of cell proliferation as well the killing of the cells. The killing of cells by necrosis or apoptosis or induction of senescence is encompassed by the invention.

Examples for cancer which can be treated by the present invention are carcinomas (breast, lung, bladder, thyroid gland, prostate, intestine, rectum, pancreas, stomach, liver, uterus, ovary) , lymphomas (non-Hodgkin-Lymphoma, Hodgkin- Lymphoma, myeloma) , leukemia (acute and chronic lymphoblastic leukemia, acute and chronic myeloblastic leukemia) , brain tumors (e.g. astrocytoma, glioma, medulloblastoma, glioblastoma, oligodendroglioma, neuroblastoma) , sarcomas (fibrosarcoma, liposarcoma, angiosarcoma, mesothelioma, chrondrosarcoma, osteosarcoma), plasmacytoma and melanoma. Moreover, the ex-vivo purging of cancer cells, e.g. in the context of autologous or heterologous stem cell transplantation, is within the scope of the invention.

Further examples for tumors which can preferable be treated by the present invention are hormone-dependent tumors such as prostate carcinoma, breast cancer, carcinoma of the thyroid gland and/or preferably leukaemia. Moreover, to the extent substances of the invention, in particular substances of the formula (I) wherein R3 or R4 are -OH, can easily cross the blood-brain-barrier, tumors of the CNS are preferable treated according to the present invention.

Glyoxalase I is up-regulated in many tumors. Generally, it is presumed that increasing concentrations of glyoxalase I correlate with the malignant phenotype of tumors. The increased concentration of glyoxalase I in tumor tissue in comparison to normal tissue is said to increase the resistance of tumors to chemotherapeutics like mitomycin C and other anti-cancer agents (Ranganathan et al . , 1995; Ayoub et al . , 1993) . Inhibition of the glyoxalase I reaction by compounds of the present invention, such as ethyl pyruvate, alone or in combination with conventional cancer therapy, such as radiation or chemotherapy is therefore advantageous for the treatment of cancer.

In this context it is important that inhibitors of glyoxalase I can compensate the effect of resistances against chemotherapeutics (Kamiya et al . , 2005). Thus, an originally successful therapy that would have to be discontinued after tumor resistance evolved, can be continued or restarted with the simultaneous application of compounds of the present invention. In a second round of chemotherapy also the first chemotherapeutic may thus be used and other chemotherapeutics exhibiting more severe side effects may be avoided. Advantageously, compounds of the present invention inhibit such cells showing a clearly increased rate of glycolysis whereas the metabolism of cells with a normal rate of glycolysis is not or only slightly affected.

Therefore, in one embodiment, the cancer is resistant to conventional therapy, such as chemotherapy and/or radiation therapy.

Moreover, the known effect of substances of the invention, such as ethyl pyruvate, as scavenger of reactive oxygen radicals represents a desired side effect for cells which do not have a high rate of glycolysis (non-cancer-cells) as such cells are additionally protected. In a combination therapy with a chemotherapeutic agent this is an additional advantage

as also normal cells are stressed, which is reduced by compounds of the present invention.

According to the invention cell proliferation is inhibited mainly in cancer cells of vertebrate animals, in particular mammals including humans.

Advantageously therapy is performed in combination with positron-emission-tomography (PET) using for example 2- [18F] fluoro-2-deoxyglucose or similar diagnostic methods observing the influx of glucose. Tumors with a high rate of glycolysis can be displayed via these therapeutic methods (Gatenby and ^■ Gillies, 2004) limited only by the resolution of PET. Each tumor that can be identified and localized by PET can therefore be treated by the method according to the present invention.

A combination of the compounds of the present invention with supporting physical therapies, e.g. hyperthermy for the treatment of cancer is also within the scope of the invention.

A further aspect is the use before, during or after application of physical treatment methods like e.g. surgery, radiation therapy or radio therapy (brachytherapy) . The kind of physical thearapy is not limited for the present invention. Examples encompass radiation therapy using cesium, iridium, iodine or cobalt as radiation source.

In one embodiment the treatment of actinic keratoses with methyl- or ethylpyruvate is excluded. In a further embodiment, the treatment of epidermal carcinoma is excluded.

b) Treatment of concomitant infectious disease Tumor patients are often in addition suffering from infectious diseases, due to a weakened immune defence, which results in a high sensitivity to infections.

Oftentimes cancer patients suffer from infectious disease caused by ubiquitous, typically non-pathogenic organisms because of this weakened immune defence, also known as opportunistic infections.

Thus, in one embodiment, the substance, pharmaceutical composition, medicament or method of treatment of the invention is for the treatment of a mammal concomitantly suffering from an infectious disease, comprising bacterial, protozoal or fungal infections, also comprising opportunistic infections. Specific examples of infectious organisms that can be treated according to the present invention comprise species belonging to the genus Candida, Aspergillus, Cryptococcus , Zygomyces, Dermatophytes, Blastomyces, Histoplasma, Coccidoides, Sporothrix, Trypanosoma, Leishmania, Plasmodium, Toxoplasma, helmithes, Acrobacter, Actinobacillus , Actinomyces, Bacteroides, Brucella, Clamydia, Clostridium, Campylobacter, Escherichia, Enterobacter, Enterococcus, Eubacterium, Fusobacterium, Helicobacter,

Hemophilus, Legionella, Listeria, Mycobacteria, Mycoplasma, Neissaria, Pasteurella, Peptostreptococcus , Pneumococcus , Pneumocystis, Porphyromonas, Prevotella, Pseudomonas, Salmonella, Shigella, Spirochetes, Staphylococcus, Streptococcus, Treponema, Vibrio, Yersinia, Escherichia coli or Pneumocystis carinii.

Degradation of glucose by glycolysis and the formation of glyoxal compounds are ubiquitous metabolic pathways, which are phylogenetically highly conserved (Heymans and Singh,

2003; Clugston et al . , 1997, Iwami et al , 1995). Cells which cover their energy consumption solely by glycolysis when glucose is available are for example yeast cells. They turn off other energy producing processes by glucose and use glycolysis (catabolite repression) . It is therefore not surprising that many infectious organisms, such as fungi,

bacteria and protozoa can also be inhibited in their growth by compounds of the present invention.

As it is known that most tumors show a high rate of glycolysis (Gatenby RA and Gillies RJ, 2004) , the growth of tumor cells and infectious agents, such as fungi can be simultaneously inhibited, which represents an increase in efficacy for the treatment of such patients.

The simultaneous inhibition of glyoxalases by compounds of the present invention such as ethyl or butyl pyruvate, ethyl or butyl lactate etc. in cancer cells as well as infectious organisms (in particular bacteria, fungi and protozoa) is particularly advantageous, as cancer cells and parasites are killed simultaneously.

Pathogenic fungi of humans or animals, including man, which cover their energy consumption mainly by glycolysis when glucose is available are for example Candida spp . , Aspergillus spp., Cryptococcus spp., Zygomyces spp., Dermatophytes, Blastomyces spp., Histoplasma spp., Coccidoides spp., Sporothrix spp.. These organisms switch off other energy producing processes by glucose and use glycolysis (catabolite repression) or grow under hypoxic conditions. It is therefore not surprising that such a multitude of cells and organisms can be inhibited in their growth and killed by compounds of the present invention.

Importantly, the compounds of the present invention also affect fungi that are resistant to conventional anti-fungal therapy, such as fluconazole resistant Candida, because they act via a different mechanism (Bennett et al , 2004) .

In addition, bacterial infections represent a significant problem in cancer therapy. The weakening of the patient by cancer per se, as well as by cancer therapy, such as chemotherapy, which weakens the immune system, favors

bacterial infections. For such patients, even ubiquitous bacteria that are non-pathogenic for healthy human beings can be dangerous (opportunistic infections) , the more so pathogenic bacteria. Importantly, the compounds of the present invention can also inhibit bacteria that are resistant against antibiotics, such as methicillin-resistant staphylococcus aureus (MRSA) , which poses severe problems in the clinical setting (Cunha, 2005) .

The simultaneous treatment of cancer and infectious organisms by the compounds according to the present invention is highly beneficial to the subject receiving such therapy, who otherwise would have to be treated with different agents at the same time. Thus, the compounds of the present invention result in synergistic effects in cancer. Moreover, the treatment of cancer with compounds of the present invention results in a prophylactic effect for the prevention of bacterial or fungal infections, at the same time as treating the tumor. These effects represent a significant therapeutic improvement, and actually lead to the reversal of side effects commonly associated with conventional chemotherapies, i.e. an increased susceptibility to infections.

e. "Postprandial state" In one embodiment the pharmaceutical composition or medicament is for use in a vertebrate having a reduced blood glucose level . The use of the compounds of the present invention for the treatment of cancer in postprandial states is also part of the invention. In postprandial states the utilization of glucose is reduced in normal cells. These states can be reached for example by long-term fasting and can be accelerated by administration of hormones or can be forced by administration of hormones. Characteristic for such states is a low blood level of glucose and a high blood level of ketone bodies. Ketone bodies can be used by the brain to generate energy such that metabolic states of the patient can be generated under control of a medical practitioner prior to

therapy wherein tumors represent the primary consumers of glucose, under conditions of reduced blood glucose levels (Sugden and Holness, 2002) .

Thus, in a postprandial state the selectivity of the therapy is enhanced, because of the reduced glucose metabolism in normal cells.

On the basis of the following figures and examples the present invention is illustrated further.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1: Inhibition of the enzymatic activity of glyoxalase I of yeast by ethyl pyruvate (EP) .

Fig. 2: Inhibition of the enzymatic activity of yeast glyoxalase I by 2-Oxopropanethioic acid S-ethyl ester (SE).

Fig. 3: Influence of ethyl pyruvate (EP), butyl pyruvate (BP) and butyl L-lactate (BL) on the enzymatic activity of yeast glyoxalase I .

Fig. 4: Influence of ethyl pyruvate (EP) on the enzymatic activity of yeast glyoxalase II.

Fig. 5: Inhibition of the enzymatic activity of glyoxalase I of human erythrocytes by ethyl pyruvate (EP) .

Fig. 6: Inhibition of the enzymatic activity of glyoxalase II of human erythrocytes by ethyl pyruvate (EP) .

Fig. 7: Effect of ethyl D-lactate (DEL), ethyl L-lactate (LEL) and ethyl pyruvate (EP) on the vitality of primary human fibroblasts.

Fig. 8: Inhibition of androgen stimulated growth of androgen dependent prostate-carcinoma cells (LNCaP) by ethyl D- lactate (DEL) .

Fig. 9: Concentration dependent inhibition of androgen stimulated growth of LNCaP cells by ethyl D-lactate (DEL) .

Fig. 10: Inhibition of androgen stimulated growth of LNCaP cells by ethyl L-lactate (LEL) .

Fig. 11: Inhibition of androgen stimulated growth of androgen dependent prostate-carcinoma cells (LNCaP) by ethyl pyruvate (EP) .

Fig. 12: Inhibition of TGF-βl stimulated growth of LNCaP cells by ethyl D-lactate (DEL) .

Fig. 13: Inhibition of leptin stimulated growth of LNCaP cells by ethyl D-lactate (DEL) .

Fig. 14: Effect of pyruvate on proliferation of prostate- carcinoma cells (LNCaP) .

Fig. 15: Influence of ethyl D-lactate (DEL) and ethyl L- lactate (LEL) on growth and morphology of_ human astrocytoma cells

Fig. 16: Inhibition of growth of human brain tumor cells by ethyl pyruvate (EP) .

Fig. 17: Inhibition of growth of human leukemia cells by ethyl pyruvate (EP) .

EXPERIMENTS

A. General experimental procedures

a) Determining enzymatic activity of yeast glyoxalase I Measuring glyoxalase I (E. C.4.4.1.5, lactoyl -glutathione lyase Sigma, G-4252) was performed according to the instructions of McLellan and Thornalley (1989) . The principle is based on measuring the initial rate of formation of S-D- lactoyl -glutathione from methylglyoxal (Sigma, MO252, 40%) and reduced L-glutathione (Aldrich, G-4251, >99%) . The formation of the product is observed using the extinction coefficient e = 2,86 mM -1 cm -1 at 240 nm. The measurement was performed in 50 mM sodium phosphate buffer, pH 7,0. For that purpose 2 mM methylglyoxal and 2 mM reduced glutathione were incubated for 2 minutes at 30 ⁰ C for the formation of the hemithioacetal . Thereafter 20 μl of a 1 to 1000 dilution of the glyoxalase I (Sigma, G-4252) was added to 1 ml of the measuring reagent to start the reaction.

Glyoxalase activity (IU) corresponds to the amount of enzyme forming 1 μmol of S-D-lactoyl-glutathione/min.

b) Determining enzymatic activity of human erythrocyte glyoxalase I

The determination of glyoxalase I was performed as described above for the yeast enzyme. After the formation of the hemithioacetal, suitable amounts (5 to 100 μl) of an erythrocyte lysate were added to 1 ml of the measuring reagent to start the reaction. The erythrocyte lysate was prepared according to the instructions of Mannervik et al . (1982) .

Glyoxalase activity (IU) corresponds to the amount of enzyme forming 1 μmol of S-D-lactoyl-glutathione/min.

c) Determining enzymatic activity of human erythrocyte glyoxalase II

The determination of erythrocyte glyoxalase II (E. C .3.1.2.6. , hydroxyacyl glutathione hydrolase) was performed according to the instructions of McLellan and Thornalley (1989) . -The principle is based on determining the initial hydrolysis of S-D-lactoyl-glutathione (L 7140, Sigma - Aldrich Chemie GmbH) in the presence of low amounts of a cell extract. Hydrolysis is observed on the basis of the reduction of the extinction at 240 nm (e = -3,1 mM ^-1 cm ^-1 ) . Glyoxalase II activity (IU) correlates to the amount of enzyme hydrolysing 1 μmol of S-D- lactoyl-glutathione/min. The measurement was performed in 100 mM Tris-HCl buffer, pH 7,4. For this purpose 0.4 mM S-D- lactoyl-glutathione was added to 1 ml of the measuring reagent and the reaction was started by addition of suitable amounts (5-100 μl) of an erythrocyte hemolysate . The erythrocyte lysate was prepared according to the instructions of Mannervik et al . (1982).

d) Protocol for experiments using LNCaP cells (androgen dependent prostate carcinoma cells,- DSMZ No ACC 256) An identical number of LNCaP cells (androgen dependent prostate carcinoma cells; DSMZ No ACC 256) were routinely cultured in 75 cm ² culture flasks in RPMI-1640 medium (Gibco; Nr. 21875-034) , penicillin/streptomycin (100 units _. penicillin/ml; 100 μg streptomycin/ml; Gibco; Nr. 15140/122) in the presence of 10% fetal calf serum (Biochrom; Nr. S0113/5; RPMI-FKS) . The flasks were incubated at 37°C in a humidified atmosphere (relative humidity >95%) of 5% CO2 in air. After reaching 50% confluency the medium was removed and the adherent cells were washed twice with PBS (phosphate buffered sodium chloride; 50 mM sodium phosphate, 150 mM NaCl, pH 7,4) . Thereafter, the cells were incubated with serum free RPMI -medium (RPMI-SF) comprising the experimental supplements in five flasks each (i.e. five replicates each). The culture was continued at 37°C, 5% C02 and 95% humidity for 24 hours. Thereafter the respective supernatants were

removed and the adherent cells were detached from the bottom of the plate by trypsin/EDTA (Gibco; No. 25300-054) and were pelleted. After resuspension and homogenization the cells were counted using a hemocytometer .

e) Protocol for experiments using human astrocytoma cells

(1321 Nl; ECACC no. 86030102)

100000 human astrocytoma cells (1321 Nl; ECACC no. 86030102) were incubated in DMEM (Gibco, no. 41966-092) , penicillin/streptomycin (100 units of penicillin/ml; 100 μg streptomycin/ml, Gibco; no. 15140/122) in the presence of 10% calf serum (Biochrom, S0113/5) , 2 mM L-glutamine, (Gibco, no.

25030-024) at 37°C, 5% CO2 in 6 well plates (Greiner, no.

657160) .

B. Data

Example 1

Inhibition of the enzymatic activity of glyoxalase I of yeast by ethyl pyruvate (EP) .

Determination of glyoxalase I activity was performed according to the general protocol as described above. The influence of ethyl pyruvate on enzyme activity was investigated by addition of increasing concentrations of EP (Sigma; no. E4, 780-8; lot. S18972-513) to the measuring reagent .

The experiments (Fig. 1) show that EP inhibits the reaction o ^' f yeast glyoxalase I in a concentration dependent manner.

Example 2

Inhibition of yeast glyoxalase I by compounds of the general formula (I), (II), and (III), respectively

Determination of glyoxalase I activity was performed according to the general protocol as described above. The

influence of compounds of the general formula (I) , (II) , and (III) on the activity of the enzyme was investigated by addition of increasing concentrations of these compounds to the preparation. The IC50-values were calculated from inhibition curves of each compound.

The data (Table 3) show that alkyl 2-oxo-derivatives inhibit the enzymatic activity of yeast glyoxalase I with different IC5 _Q S, while the alkyl 2-hydroxy-derivatives revealed no inhibitory effect at all. Thus, the experiments demonstrate that alkyl 2-hydroxy-derivatives are prodrugs which must be activated to the respective 2-oxo-derivatives in living cells or organisms.

Table 3

*GLO 1 = glyoxalase I

Example 3

Effect of prodrugs

The compounds of the general formula (II) and/or (III) can act as prodrug in the sense that the compounds are activated by enzymes within cells or in the organism, or are oxidized in vitro by addition of a suitable oxidant.

In cells or organisms lacking such activation systems the compounds of the general formula (II) and/or (III) remain inefficient. This is demonstrated by the effect of EP and LEL on the activity of glyoxalase I and the proliferation of tumor cells as well as yeast cells.

Table 4

The experiment (Table 4) shows that alkyl 2 -hydroxy derivatives have to be activated into alkyl 2-oxo-derivatives by endogenous activation systems to inhibit cell proliferation via inhibition of GLOl. In contrast to human tumor cells (LNCaP) , yeast cells lack enzyme systems for transformation of alkyl 2 -hydroxy derivatives into alkyl 2- oxo-derivatives and therefore proliferation can not be inhibited by alkyl 2 -hydroxy derivatives directly.

Example 4

Inhibition of the enzymatic activity of yeast glyoxalase I by

2-Oxopropanethioic acid S-ethyl ester (SE) .

Synthesis of 2-Oxopropanethioic acid S-ethyl ester

In a 500 ml three necked flask equipped with a reflux condenser and dropping funnel N, N' -dicyclohexylcarbodiimide

(20.6 g, 0.1 mol; Cat. No. 36650, Lot. RA 13160, Fluka,

Germany) was dissolved in dry tetrahydrofuran (200 mL; Cat. No. AE 07.1, Lot. 2121/5CR, Roth, Germany). Then, a solution of ethanethiol (6.2 g, 0.1 mol; Cat. No. EC 200-837- 3, Lot. AO200018001, Acros Organics) in tetrahydrofuran (25 mL) was added. Under stirring a solution of 2-oxopropanoic acid (8.9 g, 0.1 mol) in tetrahydrofuran (25 mL) was added dropwise within 10 min without external heating. The solution warmed up to 45°C, turned yellow and a colourless precipitate of N, N' -dicyclohexylurea appeared. After complete addition the suspension was heated to reflux for 3 min and then cooled to 0° C. The urea was filtered off and the solvent removed from the filtrate by distillation. Without other manipulations the remaining orange oily residue was rapidly distilled in the air stream of a heat gun at normal pressure yielding a yellow fraction-∞between boiling point (bp) 145 and 165 ⁰ C at normal pressure (amount of crude product 4.0 g, n^ 1.4802 (21 ⁰ C)) together with a considerable amount of brown resin in the distillation flask. The yellow crude product was redistilled in the same manner to yield 2.3 g of 2- oxopropanethioic acid S-ethyl ester as yellow oil, bp 153-157 ⁰ C, nD 1.4750 (21 ⁰ C), purity > 95 % (NMR).

IH-NMR (300.06 MHz, CDC13): δ 1.29 (-CH2-CH3), 2.41 (H3C-CO- ), 2.92 (-CH2-CH3) ; 13C-NMR (75.45 MHz, CDC13): δ 14.2 (-CH2- CH3) , 23.2 (-CH2-CH3), 23.9 (H3C-CO-), 191.4 (-CO-), 193.4 (-

CO-) . NMR spectra were measured with a Varian Mercury-300BB spectrometer. Chemical shifts are reported at the δ scale in ppm.

Determination of glyoxalase I activity

Determination of glyoxalase I activity was performed according to the general protocol as described above. The influence of 2-oxopropanethioic acid S -ethyl ester on the activity of the enzyme was investigated by addition of increasing concentrations of SE to the preparation for the measurement .

The experiment (Fig. 2) shows that SE inhibits the reaction of the glyoxalase I of yeast in a concentration dependent manner.

Example 5

Influence of ethyl pyruvate (EP) , butyl pyruvate (BP) and butyl L-lactate (BL) on the enzymatic activity of yeast glyoxalase I.

Determination of glyoxalase I activity was performed according to the general, protocol as described above. The influence of effectors on the enzymatic activity was investigated by addition of increasing concentrations (0 - 30 mM) of EP (Sigma; no. E4, 780-8; lot. S18972-513) (triangle), BP (prepared according to the instructions of patent JP 11080089; 98 %) (circle) and BL (Fluka, 69819; lot. 443090/1 21503090) (squares) to the measuring reagent (Fig. 3).

The experiments show that EP (triangles) as well as BP (circles) inhibit the activity of glyoxalase I in a concentration dependent manner wherein the effect of BP is

stronger than the effect of EP. BL (squares) does not influence the reaction of glyoxalase when it is not transformed into BP.

Example 6

Influence of ethyl pyruvate (EP) on the enzymatic activity of yeast glyoxalase II.

A colony of strain HD65-5a (Saccharomyces cerevisiae) was incubated in 5 ml YPD-medium [ (2% glucose (Fluka) , 1% yeast extract (BD, Sparks) , 2% peptone (BD, Sparks)] over night at 30 ⁰ C under rotation. A 10 ml aliquot was added to 200 ml culture medium in a 500 ml glass flask and was incubated at 30 ⁰ C on a shaker (250 U/min) . The yeast cells were harvested in the stationary growth face (O.D. lcm/600nm _{= 2} -4) by centrifugation (15 min, 3000 x g) . The cells were diluted with ¹ 0.1 M MES buffer, pH 6,5 to an O.D. of 4 and were then disrupted in a glass mill (Schwock et al . , 2004) . Subsequently the disrupted cells were centrifuged at 23000 x g, 4°, 30 min. Protein concentration of the cell free extract was determined according to the Bradford method (Bradford, 1976) .

The activity of the glyoxalase II (Hydroxyacyl glutathione hydrolase, E. C. 3.1.2.6.) was determined according to the instructions of Martins et al . (1999) in 0.1 M MES buffer, pH

6,5, 1.5 mM S-D-lactoyl-glutathione (L7140, Sigma-Aldrich

Chemistry GmbH) and 0.75 mM DTNB (Sigma, D8130) . After addition of suitable amounts of cell extract and an incubation period of 15 min at 25°C the formation of glutathione was measured at 412 nm (ε =13.6 mM ^"1 cm ^-1 ) . The

activity of the glyoxalase II (IU) correlates with the amount of enzyme hydrolysing Iμmol of S-D-lactoyl-glutathion/min.

The influence of ethyl pyruvate on the activity of the enzyme was investigated by adding increasing concentrations of EP (Sigma, No. E4 , 780-8; Lot. S18972-513) (0-2OmM) to the measurement reagent .

The relative activities of glyoxylase II in presence or absence of EP are illustrated in Fig. 4. The experiment shows that EP inhibits the reaction of yeast glyoxalase II in a concentration dependent manner.

Example 7 Inhibition of the enzymatic activity of glyoxalase I of human erythrocytes by ethyl pyruvate (EP) .

Determination of glyoxalase I activity was performed according to the general protocol as described above. The influence of ethyl pyruvate on enzyme activity was investigated by addition of increasing concentrations of EP (Sigma; no. E4 , 780-8; lot. S18972-513) (0-5OmM) to the measuring reagent .

The experiment (Fig. 5) shows that EP inhibits the reaction of glyoxalase I of human erythrocytes in a concentration dependent manner .

Example 8 Inhibition of the enzymatic activity of glyoxalase II of human erythrocytes by ethyl pyruvate (EP) .

Determination of glyoxalase II activity was performed according to the general protocol as described above. The influence of ethyl pyruvate on the activity of the enzyme was

investigated by addition of increasing concentrations of EP (Sigma, no. E 4,780-8; lot. S18972-513) (0-20 mM) to the measuring reagent .

The experiment (Fig. 6) shows that EP inhibits the reaction of glyoxalase II in a concentration dependent manner.

Example 9

Effect of ethyl D-lactate (DEL) , ethyl L-lactate (LEL) and ethyl pyruvate (EP) on the vitality of primary human fibroblasts .

An identical number (104 cells per well) of primary human skin fibroblasts were inoculated in 24 -well plates (Greiner, no. 662160) and were cultured in DMEM (Gibco; no. 41966-092) in the presence of 10 % calf serum (Biochrom, S0113/5) , 2 mM L-glutamine (Gibco; no. 25030-024), penicillin/streptomycin (100 units penicillin/ml; 100 μg streptomycin/ml, Gibco; no. 15140/122), 5 mg% ascorbic acid (Serva, no. 14030.02) at 37°C, 5%CO2 and 95% humidity. The primary human fibroblasts were prepared according to the instructions of Birkenmeier et al . (1998) . After reaching 50 % confluency the medium was by fresh serum free medium. Thereafter the following supplements were added to the cells: preparation 1 (equivalent volume of serum free (SE; _. ) medium, blank) ; preparation 2 (1 mM DEL or 1 mM LEL or 1 mM EP) ; preparation 3 (5 mM DEL or 5 mM LEL or 5 mM EP) , preparation 4 (10 mM DEL or 10 mM LEL or 10 mM EP) , preparation 5 (20 mM DEL or 20 mM LEL or 20 mM EP) , preparation 6 (50 mM DEL or 50 mM LEL or 50 mM EP) . The culture was continued at 37°C, 5% C02 and 95% humidity for 24 hours. Thereafter the supernatants were removed and 100 μl of a 50 % thymol blue solution was added to the wells. After washing the cells with medium the unstained and stained cells were counted under the light optical microscope comprising a coordinate plane. Cells stained blue were assessed as avital, unstained cells as vital. The percentage of unstained cells

of the total number of cells corresponds to the vitality of the cells.

The experiment (Fig. 7) shows that DEL, LEL and EP are not 5 toxic over the concentration range investigated and that they do not significantly influence vitality of primary human fibroblasts .

Example 10 10 Inhibition of androgen stimulated growth of androgen dependent prostate-carcinoma cells (LNCaP) by ethyl D-lactate (DEL) .

LNCaP cells were cultured according to the general protocol 15 described above, and were incubated with: (i) 0,09% DMSO,

(ii) 10 nM DHT (Sigma; A-8380) in DMSO, (iii) 10 nM DHT + 10 mM Ethyl D-lactate (DEL) and (iv) 10 mM DEL.

The experiment (Fig. 8) shows that DHT stimulated the growth 20 of LNCaP cells (p = 0,006 [blank vs. DHT]) . In the presence of DEL androgen stimulated growth is suppressed (p= 0,01 [DHT vs. DHT+DEL] ) . DEL does not show an effect on the growth of unstimulated tumor cells (p= 0,88 [blank vs. DEL]).

25 _. Example 11 , _λ

Concentration dependent inhibition of androgen stimulated growth of LNCaP cells by ethyl D-lactate (DEL) .

LNCaP cells were cultured according to the general protocol 30 described above, and were incubated with: preparation 1 (0,09 % DMSO) ; preparation 2 (10 nM DHT) ; preparation 3 (10 nM DHT + 1 mM DEL) ; preparation 4 (10 nM DHT + 5 mM DEL) ; preparation 5 (10 nM DHT + 10 mM DEL) ; preparation 6 (10 nM DHT + 20 mM DEL) ; preparation 7 (10 nM DHT + 50 mM DEL) . 5

The experiment (Fig. 9) shows that the proliferation of DHT- stimulated LNCaP cells depends on the concentration of DEL.

The IC50 of proliferation is already reached at 1 niM DEL. Inhibition of proliferation by increasing DEL concentrations is significant in all cases (p< 0,05).

Example 12

Inhibition of androgen stimulated growth of LNCaP cells by- ethyl L-lactate (LEL) .

LNCaP cells were cultured according to the general protocol described above, and were incubated with: (i) 0,09 % DMSO, (ii) 10 nM DHT in DMSO, (iii) 10 nM DHT + 10 mM ethyl L- lactate (LEL) and (iv) 10 mM LEL.

The experiment (Fig. 10) shows that DHT stimulates the growth of LNCaP cells (p= 0,006 [blank vs. DHT]) . In the presence of LEL, the androgen stimulated growth is suppressed (p= 0,045 [DHT vs. DHT + LEL] ) . LEL does not show an effect on the growth of un stimulated tumor cells (p= 0,49 [blank vs. LEL] ) .

Example 13

Inhibition of androgen stimulated growth of androgen dependent prostate-carcinoma cells (LNCaP) by ethyl pyruvate (EP) .

LNCaP cells were cultured according to the general protocol described above, and were incubated with: (i) 0,09% DMSO, (ii) 10 nM DHT (Sigma; A-8380) in DMSO, (iii) 10 nM DHT + 1 mM ethyl pyruvate (EP) , (iv) 10 nM DHT + 5 mM ethyl pyruvate (EP) (v) 10 nM DHT + 1OmM ethyl pyruvate (EP) .

The experiment (Fig. 11) shows that DHT stimulated the growth of the LNCaP cells (p=0,007 [blank vs. DHT]). In the presence of EP the androgen stimulated growth is suppressed (p= 0,043 [1 mM EP], p=0,02 [5mM] , and p<0.001 [1OmM EP], DHT versus DHT + EP) .

Example 14

Inhibition of TGF-βl stimulated growth of LNCaP cells by- ethyl D-lactate (DEL) .

LNCaP cells were . cultured according to the general protocol described above,, and were incubated with: preparation 1 (equivalent volume of RPMI-SF) ; preparation 2 (10 ng/ml TGF- βl (Stratman, No. 9515500) ; preparation 3 (10 ng/ml TGF-βl + 10 mM DEL) ; preparation 4 (10 mM DEL) .

The experiment (Fig. 12) shows that DEL significantly inhibits the TGF-βl-caused stimulation of tumor cell proliferation (p = < 0,001 [blank vs. TGF-βl]; p = 0,003 [TGF-βl vs. TGF-βl + DEL]).

Example 15

Inhibition of leptin stimulated growth of LNCaP cells by ethyl D-lactate (DEL) .

LNCaP cells were cultured according to the general protocol described above, and were incubated with: preparation 1 (equivalent volume of RPMI-SF) ; preparation 2 (100 ng/ml leptin) ; preparation 3 (100 ng/ml leptin + 10 mM DEL) ; preparation 4 (10 mM DEL) .

The experiment (Fig. 13) shows that DEL significantly inhibits leptin-caused stimulation of tumor cell proliferation (p = 0,001 [blank vs. leptin]; p = 0,001 [leptin vs leptin + DEL] ) .

Example 16

Effect of pyruvate on proliferation of prostate-carcinoma cells (LNCaP) .

LNCaP cells were cultured according to the general protocol described above, and were incubated with: preparation (1) 0,09 % DMSO; (2) 10 nM DHT; (3) 10 nM DHT + 1 mM pyruvate;

(4) 10 nM DHT + 5 mM pyruvate; (5) ; 10 nM DHT + 10 mM pyruvate; (6) 1 mM pyruvat ; (7) 5 mM pyruvate; (8) 10 mM pyruvate .

The experiment (Fig. 14) shows that pyruvate did not diminish the DHT-induced proliferation of LNCaP cells (p<0,001 [blank vs. DHT]; p>0,05 [DHT vs. DHT+1 mM pyruvate]; p>0.05 [DHT vs. DHT+5 mM pyruvate]; p>0.05 [DHT vs. DHT+10 mM pyruvate] as has been demonstrated for the compounds of the invention. These data clearly contradict earlier speculations on pyruvate (Stanko et al , 1994) . Rather, pyruvate itself exhibits stimulatory effects on proliferation of tumor cells in the absence of DHT (p<0,001 [1 mM pyruvate] ; p<0,001 [5 mM pyruvate] ; p<0.001 [10 mM pyruvate] .

Example 17

Influence of ethyl D-lactate (DEL) and ethyl L-lactate (LEL) on growth and morphology of human astrocytoma cells

Human astrocytoma cells (1321N1; ECACC no. 86030102) were cultured as described above. After addition of 20 mM DEL and LEL, respectively, the tumor cells were for another 24 hours. Thereafter the cells were inspected using a light optical microscope (Axioplan 2, Carl Zeiss) and documented (Fig. 15) .

Fig. 15A shows non treated tumor cells (normal cell configuration; adherent growth; broad cytoplasm; strong cell- cell contacts), Fig. 15B shows DEL treated tumor cells (needle shaped structure; almost no cytoplasm; loss of cell- cell contacts; low cell adhesion, reduced cell number), Fig. 15C shows LEL treated tumor cells (needle shaped; missing cytoplasm; loss of cell-cell contacts, low cell adhesion, reduced cell number) .

The experiments show that ethyl lactate dramatically changes the morphology and functional characteristics of tumor cells and inhibits their growth by starvation.

Example 18

Inhibition of growth of human brain tumor cells by ethyl pyruvate (EP) .

Human astrocytoma cells (1321N1; ECACC no. 86030102) were cultured as described above. After addition of increasing concentrations of ethyl pyruvate the tumor cells were incubated for another 24 hours. Thereafter 20 μl WST-I reagent (Roche, no. 1644807) were added to each well and absorption at 450/620 nm was measured after 3 hours. The staining is proportional to cell number.

At all concentrations marked with an asterisk (5 mM, 10 mM and 20 mM) significant differences in cell number can be observed in comparison to untreated cells (p < 0,05).

The experiment (Fig. 16) shows that proliferation of human brain tumor cells is significantly inhibited by EP.

Example 19

Inhibition of growth of human leukemia cells by ethyl pyruvate (EP) .

Human acute monocytic leukaemia cells (THP-I; DSMZ no. ACC 16) were cultured in RPMI-1640 medium (Gibco no. 21875-034) in the presence of 10% calf serum (Biochrom, S0113 / 5) , penicillin/streptomycin (100 units penicillin/ml; 100 μg streptomycin/ml, Gibco; no. 15140/122) , 20 mM Hepes (Gibco, no. 15630-056) , 2 mM L-glutamine (Gibco; no. 25030-024) at

37°C and 5% C02 for 24 hours. 10000 cells each were pipetted into the wells of 96 well culture plates (Greiner; no. 655180) and were mixed with ethyl pyruvate until the indicated concentrations were obtained. Thereafter the cells were cultured for another 24 hours. Subsequently, 20 μl WST-I reagent (Roche, no. 1644807) was added to each well and absorption at 450/620 nm was measured after 3 hours.

According to manufacturer's instructions the staining is proportional to the number of cells.

At all concentrations marked by an asterisk significant differences in cell numbers can be observed in comparison to untreated cells (p < 0,05) .

The experiment (Fig. 17) shows that proliferation of leukaemia cells is inhibited by ethyl pyruvate.

Example 20:

Pharmaceutical composition for infusion

A solution for infusion comprising the substances of the invention is prepared as follows:

The compound of the invention, e.g. sterile ethyl pyruvate and/or ethyl lactate, is mixed with sterile 250 ml Lactated Ringers Balanced Salt Solution, pH 7.5 , to achieve a final concentration of 0.05% to 10% per volume, e.g. 0.05%, 0.5%,

1%, 5%, or 10% per volume. The pH of the solution is adjusted to 7.5 with NaOH, if necessary. After sterilization, the solution is packed in plastic containers and stored at 4°C. The composition of lactated Ringers Balanced Salt Solution is as follows:

Sodium 130 mM,

Calcium 3 , 7 mM, Potassium 5,4 mM,

Chloride 111,7 mM

Lactate 27,2 mM.

Example 21:

Pharmaceutical composition for bolus injection

A solution for bolus injection can be prepared according to Example 22, wherein the concentration of the substance of the invention is adapted accordingly.

Example 22: Cream

A cream comprising a substance of the invention is prepared from the following ingredients:

aqueous phase: butyleneglycol 4% substance of the invention 25% water to 100% lipid phase: steareth-2 3% steareth-21 2% glycol-15-stearylether 9% cetearylalcohol 2,5% therafter addition of: phenoxyethanol , methylparaben, ethylparaben, propylparaben, butylparaben 0,5% butylenglycol 0,5% tocopherole 0,2%

Example 23 : Ointment

An ointment of the oil-in-water-emulsion type, comprising a compound of the invention is prepared from the following ingredients .

A product of the invention 10-20% butyleneglycol 5% glycerol 4% sodium dihydroxy cetylphosphate, isopropyl hydroxy cetylether 2% water to 100%

B glycolstearate SE 15%

octylcocoate 11%

butyleneglycol , metylparabene ethylparabene, propylparabens, pH: adjusted to 5,5 2%

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List of abbreviations

2 -DG 2-deoxyglucose

ATP Adenosine triphosphate BBB Blood Brain Barrier

BL butyl lactate

BMP bone morphogenic protein

BP butyl pyruvate

CNS Central nervous system CSF colony stimulation factor

DBL butyl D- lactate

DEL Ethyl D- lactate

DHT dihydro testosterone

DMEM Dulbecco's modified Eagle Medium DMSO dimethyl sulfoxide

DSMZ German Collection of Microorganisms and Cell

Cultures GmbH (Deutsche Sammlung von Mikroorganismen und

Zellkulturen GmbH)

DTNB 5, 5"-dithiobis (2-nitro benzoic acid) ECACC European Collection of Cell Cultures

E. C. Enzyme Commission

EDTA ethylene diamine tetraacetate

EGF epidermal growth factor

EOB ethyl -2-oxo-butyrate EP ethyl pyruvate

EPO erythropoietin

FGF fibroblast growth factor

FCS fetal calf serum

GLO 1 Glyoxalase 1 HEPES 4- (2 -hydroxyethyl) -1-piperazineethanesulfonic acid

HGF hepatocyte growth factor

IC- 50 Inhibitor concentration to reach 50% of the maximal effect

IU international unit IGF insulin-like growth factor

IL interleukine

INF interferon

LBL Butyl L- lactate

LEL Ethyl L- lactate

MES 4-morpholine ethanesulfonic acid

MCT monocarboxylate transporter MIC Minimal inhibition concentration

MRSA Methicillin-resistant Staphylococcus Aureus

MSSA Methicillin-sensitive Staphylococcus Aureus

NFkB nuclear factor kappa B

NGF nerve growth factor INF interferon

O.D. optical density

PBS phosphate buffered saline

PDGF platelet -derived growth factor

PET positron emission tomography RPMI Rosswell Park Memorial Institute

SF serum free

TGF- transforming growth factor beta

TNF Tumor necrosis factor

VEGF Vascular endothelial growth factor YPD yeast peptone dextrose medium