60/173, 375, filed December 28, 1999 which is incorporated herein by reference.

FIELD OF THE INVENTION The invention relates to hyaluronic acid and a second anti-neoplastic agent in the treatment of cancer.

BACKGROUND OF THE INVENTION Hyaluronic acid (hereinafter,"HA") is a glycosaminoglycan with repeating disaccharide units of D-glucuronic acid and N-acetyl-D-glucosamine that exists as a high molecular mass polymer (106to 107 Da) in its native form (Laurent et al. FASEB J. 6 : 2397, 1992). HA is a major non-structural component of connective tissue and is important for maintaining extracellular matrix architecture and for promoting cell motility, adhesion and proliferation (Entwistle, J. Cell. Biochem. 61 : 569, 1996).

The effects of both low molecular mass HA (5 x 105 Da) and high molecular mass HA ( ! 5 x 105 Da) on normal cells has been studied extensively (McKee et al. J.

Biol. Chem. 272 : 8013, 1997 ; Hodge-Dufour J. Immunol. 159 : 2492, 1997 ; Rooney et al. Int. J. Cancer 60 : 632, 1995). However, little is known about the effects of HA on malignant cells. In vitro, HA (>0. 320 mg/ml) inhibited proliferation of B16F10 murine melanoma cells by 50 to 90%. In vivo, HA (1 mg/ml) administrated over 7 days by an Alzet osmotic pump into the immediate vicinity of a B16F10 murine melanoma tumor, reduced tumor volume >85%. In vivo, HA (>750 mg/kg) administered with various other therapeutic agents over various periods of time, reduced or eliminated rectal, gastric, breast, prostate and endometrial cancers (PCT/CA/00283). In vivo, hyaluronan (HA) (7. 5 mg/kg) administered with 2. 5 mg/kg of the lipophilic, tubulin-stabilizing, chemotherapeutic drug paclitaxel (TAXOL) decreased tumor mass of colon 26-cells seeded into BALB/c mice. It was proposed that the water-insoluble paclitaxel binds to hydrophobic patches on HA and that the HA binds to HA receptors on the surface of malignant cells and, thereby,

delivers the paclitaxel directly to the malignant cells (PCT/CA98/00660). That is, HA functions as a delivery agent for the paclitaxel and the efficiency of this delivery depends on the expression of HA cell surface receptors such as CD44. However, as colon-26 cancer cells express high levels of HA receptors, HA alone significantly inhibits the growth of these cancer cells (Freemantle et al. Int. J. Tissue React.

17 : 157, 1995).

Cancer is an aberrant net accumulation of atypical cells that results from an excess of cell proliferation, an insufficiency of cell death, or a combination of the two.

Cell proliferation is characterized by replication of total cellular DNA and the division of one cell into two cells (Hochhauser D. Anti-Cancer Chemotherapy Agents 8 : 903, 1997). Cell death is affected by immune-mediators including, but not limited to, IL-6 and IL-12 that initiate cytolytic processes and that promote apoptosis, and from apoptosis inducers that directly initiate pathways leading to cell death (Muzio et al.

Cell 85 : 817, 1996 ; Levine, A. Cell 88 : 323, 1997).

Current cancer treatments act by inhibiting proliferation of cancer cells or by inducing apoptosis in cancer cells. However, many of these treatments have proven to be less than adequate for clinical applications and, at standard dosages, are inefficient or toxic, have significant adverse side-effects, result in development of drug resistance or immunosensitization, are debilitating and compromise the quality of life of the patient. Moreover, the costs of these treatments are substantial, both to the individual patient and to society.

Therefore, there is a continuing need for novel cancer treatments that inhibit proliferation of cancer cells, induce apoptosis in cancer cells, are effective at dose regimens associated with minimal toxicity, and are cost effective.

SUMMARY OF THE INVENTION The present invention fulfills these needs by providing a composition and method comprising purified HA, a second anti-neoplastic agent and a pharmaceutically acceptable carrier, wherein the HA and the second anti-neoplastic agent act synergistically to potentiate each other's effect on cancer cells.

HA is a nontoxic anti-neoplastic agent that acts synergistically with a second anti-neoplastic agent including, but not limited to, a toxic chemotherapeutic drug to

inhibit proliferation and induce apoptosis in cancer cells. As the HA and the toxic chemotherapeutic drug potentiate each other's effect on cancer cells, the standard dose of the toxic chemotherapeutic drug can be reduced without compromising the therapeutic effectiveness of the cancer treatment. Moreover, as HA is inexpensive and as most chemotherapeutic drugs are expensive, the combined use of HA and a chemotherapeutic drug can reduce significantly the cost of cancer treatment. The increase in dose effectiveness, decrease in toxicity and decrease in cost address long felt unfulfilled needs in the medical arts and provide important benefits for mammals, including humans.

Accordingly, it is an object of the present invention is to provide a composition and method effective to treat cancer in a mammal, including a human.

Another object is to provide a composition and method that reduces the toxic side-effects of cancer treatments.

Another object is to provide a composition and method that reduces the cost of cancer treatments.

Another object is to provide a composition and method, wherein two or more anti-neoplastic agents act synergistically on cancer cells.

Another object is to provide a composition and method that inhibits proliferation of cancer cells.

Another object is to provide a composition and method that induces apoptosis in cancer cells.

Another object is to provide a composition and method that potentiates the effect of chemotherapeutic drugs on cancer cells.

Another object is to provide a composition and method that potentiates the effect of anti-neoplastic nucleic acids on cancer cells.

Another object is to provide a composition and method that potentiates the effect of anti-neoplastic bacterial DNAs on cancer cells.

Another object is to provide a composition and method that potentiates the effects of anti-neoplastic bacterial DNA-bacterial cell wall complexes on cancer cells.

Another object is to provide a composition and method that potentiates the effect of anti-neoplastic bacterial cell wall extracts on cancer cells.

Another object is to provide a composition and method that potentiates the effect of anti-neoplastic synthetic oligonucleotides on cancer cells.

Another object is to provide a composition and method that stimulates the production of cytokines by immune system cells.

Another object is to provide a composition and method that stimulates the production of IL-6 by immune system cells.

Another object is to provide a composition and method that stimulates the production of IL-12 by immune system cells.

These and other objects, features and advantages of the present invention will become apparent after a review of the following detailed description of the disclosed embodiment and the appended claims.

DETAILED DESCRIPTION OF THE INVENTON The present invention provides a composition comprising purified HA, a second anti-neoplastic agent and a pharmaceutically acceptable carrier, wherein the HA and the second anti-neoplastic agent act synergistically to potentiate each other's effect on cancer cells. The present invention also provides a method, wherein a composition comprising purified HA, a second anti-neoplastic agent and a pharmaceutically acceptable carrier is administered to a mammal having cancer in an amount effective to treat the cancer.

As used herein,"hyaluronic acid (HA)"refers to hyaluronan, hyaluronate, salts of HA, homologues. analogues, derivatives, complexes, esters. fragments and subunits of HA that have been tested and found suitable for use in a mammal, including a human.

As used herein,"anti-neoplastic agent"refers to any agent that inhibits the growth or metastases of a cancer.

As used herein,"chemotherapeutic drug"refers to any drug approved by a regulatory agency of a country or a state government or listed in the U. S.

Pharmacopoeia or other generally recognized pharmacopoeia to treat cancer in a mammal, including a human.

As used herein,"non-lipophilic"refers to a chemotherapeutic drug having greater than zero solubility in water.

As used herein,"standard dose"refers to the dose or dose range suggested in the U. S. Pharmacopoeia or other generally recognized pharmacopoeia to treat cancer in a mammal, including a human.

As used herein,"synergism"refers to the coordinated action of two or more agents on the growth or metastases of a cancer.

As used herein,"potentiates"refers to a degree of anti-cancer activity that is greater than additive.

As used herein"toxic"refers to the adverse side-effects of an anti-neoplastic agent as included in the U. S. Pharmacopoeia or other generally recognized pharmacopoeia.

HA is highly viscous, highly electronegative and highly hydrophilic. Various methods for the isolation, purification and fractionation of HA are known to those skilled in the art. In addition, molecular mass fractions of purified HA can be purchased from commercial sources including, but not limited to, Fluka Chemical Corporation (Ronkonkoma, NY, USA), Genzyme Corporation (Cambridge, MA, USA), Lifecore Inc. (Chaska, MN, USA), Hyal Pharmaceutical Corporation (Mississauga, Ontario, Canada) and Bioniche Life Sciences, Inc. (Belleville, Ontario, Canada).

Anti-neoplastic agents include, but are not limited to, chemotherapeutic drugs, biologicals, immunostimulants, cytokines, antigens, antibodies, nucleic acids, synthetic oligonucleotides, vaccines, aptamers nucleic acids, antisense nucleic acids, immunomodulators, telomerase inhibitors, caspase activators, apoptosis inducers, cyclin inhibitors, CDK inhibitors, stable triple helix forming agents, genetically engineered, biologically engineered and chemically synthesized agents, agents that target cell death molecules for activation or inactivation, and combinations thereof.

Chemotherapeutic drugs include, but are not limited to, DNA-alkylating agents, DNA-cross-linking agents, antibiotic derivatives, topoisomerase inhibitors, tubulin stabilizers, tubulin destabilizers, antimetabolites, nitrogen mustard derivatives, steroids, hormone antagonists, protein kinase inhibitors, HMG-CoA inhibitors, metaloproteinase inhibitors, angiogenesis inhibitors, CDK inhibitors, cyclin inhibitors, caspase inhibitors, RNA. antisense RNA, DNA, antisense DNA, bacterial extracts, bacterial DNA, bacterial DNA-bacterial cell wall complexes, synthetic

oligonucleotides, molecular biologically modified viral and bacterial components. and combinations thereof.

Pharmaceutically acceptable carriers include liquid carriers, solid carriers, or both. Liquid carriers include, but are not limited to, water, saline, physiologically acceptable buffers, aqueous suspensions, oil emulsions, water in oil emulsions, water- in-oil-in-water emulsions, site-specific emulsions, long-residence emulsions, sticky- emulsions, microemulsions and nanoemulsions. Preferred aqueous carriers include, but are not limited to, water, saline and physiologically acceptable buffers. Preferred non-aqueous carriers include, but are not limited to, a mineral oil or a neutral oil including, but not limited to, a diglyceride, a triglyceride, a phospholipid, a lipid, an oil and mixtures thereof. Solid carriers are biological carriers, chemical carriers, or both and include, but are not limited to, particles, microparticles, nanoparticles, microspheres, nanospheres, minipumps, bacterial cell wall extracts, and biodegradable or non-biodegradable natural or synthetic polymers that allow for sustained release of the composition (Brem et al. J. Neurosurg. 74 : 441, 1991).

Cancers include, but are not limited to, squamous cell carcinoma, fibrosarcoma, sarcoid carcinoma, melanoma, mammary cancer, lung cancer, colorectal cancer, renal cancer, osteosarcoma, cutaneous melanoma, basal cell carcinoma, pancreatic cancer, bladder cancer, brain cancer, ovarian cancer, prostate cancer, leukemia, lymphoma and metastases derived therefrom.

Preferably, the molecular mass of the HA used is between about 1 x 103 and 1 x 107 Da, more preferably between about 5 x 104 and I X 106 Da, and most preferably between about l x 104 and 8 x 105 Da. Preferably, the amount of HA administered per dose is from about 0. 001 to 25 mg/kg, more preferably from about 0. 01 to 15 mg/kg, and most preferably from about 0. 1 to 10 mg/kg. The amount of anti- neoplastic agent administered per dose depends on the anti-neoplastic agent used and is preferably about 5 to 75% of the standard dose, more preferably from about 5 to 50% of the standard dose, and most preferably from about 5 to 10% of the standard dose.

Routes of administration include, but are not limited to, oral, topical, subcutaneous, transdermal, subdermal, intra-muscular, intra-peritoneal, intra-vesical, intra-articular, intra-arterial, intra-venous, intra-dermal, intra-cranial, intra-lesional,

intra-tumoral, intra-ocular, intra-pulmonary, intra-spinal, placement within cavities of the body, nasal inhalation, pulmonary inhalation, impression into skin, electrocorporation, osmotic minipumps, and through a cannula to the site of interest.

Depending on the route of administration, the volume per dose is preferably about 0. 001 to 100 ml per dose, more preferably about 0. 01 to 50 ml per dose, and most preferably about 0. 1 to 30 ml per dose. The dose can be administered in a single treatment or in multiple treatments on a schedule and over a period of time appropriate to the cancer being treated, the condition of the recipient, and the route of administration. Moreover, the HA can be administered before, at the same time as, or after administration of the anti-neoplastic agent as long as both are administered within a 24 hour time period.

In an example, 100 mg of < 1. 5 X 104 Da HA + 4 mg/kg of the antimetabolite fluorinated pyrimidine 5-fluorouracil (hereinafter,"5-FU" ; standard dose 12mg/kg) are administered intravenously to a mammal having cancer in a number of doses and over a period of time effective to treat the cancer. In another example, 100 mg of 5. 0- 7. 5 X 105 Da HA + 2 mg/kg of 5-FU are administered intratumorally to a mammal having a cancer in a number of doses and over a period of time effective to treat the tumor. In another example, 100 mg of 5. 0-7. 5 X 105 Da HA + 1. 2 mg/kg of 5-FU are administered intratumorally to a mammal having a cancer in a number of doses and over a period of time effective to treat the tumor. In another example, 100 mg of 1-3 X 105 Da HA + 10 mg/m2 of the alkylating agent cisplatin (PLATINOL@ ; hereinafter, "CIS" ; standard dose 100 mg/m2) is administered intravenously to a mammal having cancer in a number of doses and over a period of time effective to treat the cancer. In another example, 100 mg of 3-5 X 105 Da HA + 36 mg/m2 of the DNA cross-linker carboplatin (PARAPLATIN ; standard dose 360 mg/m2) is administered intravenously to a mammal having a cancer in a number of doses and over a period of time effective to treat the cancer.

The amount of HA per dose, the particular second anti-neoplastic agent used, the amount of the second anti-neoplastic agent per dose, the dose schedule and the route of administration should be decided by the practitioner using methods known to those skilled in the art and will depend on the type of cancer, the severity of the cancer, the location of the cancer and other clinical factors such as the size, weight

and physical condition of the recipient. In addition, in vitro assays may be employed to help identify optimal ranges for HA + anti-neoplastic agent administration.

The following examples will serve to further illustrate the present invention without, at the same time, however, constituting any limitation thereof. On the contrary, it is to be clearly understood that resort may be had to various other embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the present invention and/or the scope of the appended claims.

Example 1 Cells All cell lines were obtained from the American Type Culture Collection (ATCC, Rockville, MD, USA) and were cultured in the medium recommended by the ATCC.

Table 1 shows the cell lines, their origins and their properties.

Table 1 Cell lines CELL LINE ORIGIN PROPERTIES MCF-7 Human breast cancer Caspase 3-negative ; estrogen-dependent PC-3 Human prostate cancer53 mutated ; androgen-independent (hormone refractory) LNCaP Human prostate cancer TGF-beta I receptor-negative ; androgen-dependent Du-145 Human prostate cancer Fas-resistant ; Rb-mutated, p53 mutated ; androgen independent T-24 Human bladder cancer p53 mutated RT-4 Human bladder cancer N. D. UMUC-3 Human bladder cancer P-glycoprotein over-expression HT-1376 Human bladder cancer p53 and p21 (waf-1) mutated HT-1080 Human fibrosarcoma N. D. B-16FI Murine melanoma N. D.

Example 2 Reagents HA, purified from Streptococcus sp., was obtained from Lifecore Inc.

(Chaska, MN, USA) and was dissolved in sterile saline at 0. 8 mg/ml (CYSTISTAT@,

Bioniche Life Sciences Inc., Belleville, Ontario, Canada) or at 10. 0 mg/ml (SUPLASYN', Bioniche Life Sciences Inc., Bellville, Ontario, Canada).

Mycobacterium phlei-DNA (hereinafter,"M-DNA") and M-DNA- Mycobacterium phlei cell wall complex (hereinafter,"MCC") were prepared as in US Application No. 09, 129, 312 (incorporated by reference herein).

Example 3 Preparation of HA of < 5. 0 x 105 Da HA of <5. 0 x 105 Da was prepared from HA of 5. 0-7. 5 x 105 Da by digestion with hyaluronidase type IV-S derived from bovine testes (Sigma-Aldrich Canada, Oakville, Ontario, Canada) for 60 minutes at 37°C, by sonication on ice (Branson Sonifier Model 450, Danbury, CT, USA) for 20 minutes at maximal intensity, or by autoclaving (Amsco-Steris International. Model 2002, Mentor, OH, USA) for 30 minutes.

The HA obtained was electrophoresed in 0. 5% agarose gels prepared in TAE buffer (40 mM Tris, 20 mM acetic acid and 2. 0 mM EDTA, pH 7. 9) for 3 hours at 100 V (Lee et al. Anal. Biochem. 219 : 278, 1994). The molecular mass distribution of the HA was visualized using 0. 005% of the cationic dye Stains-All (1-Ethyl-2- [3- (1- ethylnapthol [1, 2-d] thiazolin-2-ylidene)-2-methylpropenyl] napthol [1, 2-d] thiazolium Bromide ; Sigma-Aldrich, Oakville, Ontario, Canada) and the gel photo was scanned using 1D software (Advance American Biotechnology, Fullerton, CA, USA). The molecular mass of HA was <1. 5 x 104 Da after hyaluronidase, about 1. 0-3. 0 x 105 Da after sonication, and about 3. 0-5. 0 x 105 Da after autoclaving.

Example 4 Measurement of cell proliferation Cell proliferation was measured using dimethylthiazoldiphenyltetrazolium (MTT) reduction (Mosman et al. J. Immunol. Methods 65 : 55, 1983). Unless otherwise stated, 100 gel of 5 mg/ml of MTT (Sigma-Aldrich, St. Louis, MO, USA) dissolved in PBS was added into each well. After 4 h, medium was removed from each well, 1. 0 ml of acid-isopropanol (0. 04 N HCl in isopropanol) was added and reduced MTT was solubilized by mixing. Absorbency of the reaction product was measured at a wavelength of 570 nm using a multiplate spectrophotometer reader (Elx800 Model, Bio-TEK Instruments Inc., Winooski, Vermont, USA).

Example 5 Inhibition of cell proliferation with HA Unless stated otherwise 1. 0 x 105 cells/ml were seeded in 6-well flat-bottom tissue culture plates and were maintained for 48 h at 37° C in a 5% C02 atmosphere.

PC-3, LNCaP and Du-145 human prostate cancer cells ; MCF-7 human breast cancer cells ; HT-1080 human fibrosarcoma cancer cells ; B16F1 murine melanoma cells ; and, UMUC-3, RT-4, HT-1376 and T-24 human bladder cancer cells were incubated with 0. 8, 8. 0 and 801lg/ml of 5. 0-7. 5 x 105 Da HA (Table 2).

Table 2 Inhibition of cell proliferation with 0. 5-7. 5 x 105 Da HA % INHIBITION CELLS 0.8 µg/ml 8.0 µg/ml 80. 0 g/ml PC-3 15 26 30 LNCaP 7 13 26 Du-145 6 15 38 MCF-7 19 24 35 HT-1080 4 4 36 B16FI 20 20 30 UMUC-3 10 10 2 RT-412135 HT-1376 0 3 1 T-24 10 8 0

As shown in Table 2, inhibition of proliferation of PC-3, LNCaP, Du-14, MCF-7, HT-1080 and B16F1 cancer cells increased with increasing concentrations of HA, whereas. inhibition of proliferation of UMUC-3, RT-4, HT-1376 and T-24 cancer cells did not increase with increasing concentrations of HA.

PC-3, LNCaP and Du-145 human prostate cancer cells were incubated with 8. 0 µg/ml of 5. 0-7. 5 x Da HA or of <1. 5 x 104 Da HA (Table 3).

Table 3 Inhibition of cell proliferation

% INHIBITION CELLS 5.0-7.5 x 105 Da HA <1.5 x 104 Da HA 8. 0/mol 8. 0 e/ml PC-3 26 5 LNCaP 13 24 Du-145 15 37 PC-3 cancer cell proliferation was inhibited more by 5. 0-7. 5 x 105 Da HA, whereas LNCaP and Du-145 cancer cell proliferation was inhibited more by <1. 5 x 104 Da HA.

Example 6 HA potentiation of the anti-neoplastic effect ofM-DNA and MCC Unless stated otherwise 2. 0 x 104 cells/ml were seeded in 24-well plates and were maintained for 48 h at 37° C in a 5% C02 atmosphere. MTT was used at 50 µl per well.

T-24 human bladder cancer cells, PC-3 and Du-145 human prostate cancer cells, and MCF-7 human breast cancer cell were incubated with saline or with 80. 0 g/ml of 5. 0-7. 5 x 105 Da HA + 1. 0 µg/ml of M-DNA (Table 4).

Table 4 HA potentiation of M-DNA inhibition of cell proliferation % INHIBITION 5. 0-7. 5 x 105 Da HA CELLS Saline 80. 0 pg/ml T-24 + saline 0 T-24+ M-DNA 28 36 PC-3 + saline 0 30 PC-3 + M-DNA 10 50 Du-145+saline 0 38 Du-145+M-DNA 11 58 MCF-7+ saline 35 MCF-7 + M-DNA 13 52

As shown in Table 4, HA potentiated the anti-neoplastic effect of M-DNA on T-24, PC-3, Du-145 and MCF-7 cancer cells.

HT-1376, RT-4 and T-24 human bladder cancer cells were incubated with 0. 8 µg/ml of 5. 0-7. 5 x Da HA + 1. 0 µg/ml of MCC (Table 5).

Table 5 HA potentiation of MCC inhibition of cell proliferation % INHIBITION CELLS Saline 5. 0-7. 5 x 10~ Da HA at 0. 8 ug/ml HT-1376 + saline 0 3 HT-1376 + MCC 34 RT-4 + saline 0 13 RT-4 + MCC 16 37 T-24 + saline 0 8 T-24+MCC 31 45

As shown in Table 5, HA potentiated the anti-neoplastic effect of MCC on H-1376, RT- 4 and T-24 cancer cells.

Example 7 HA potentiation of the anti-neoplastic effect of synthetic oligonucleotides MCF-7 human breast cancer cells (2. 5 X 105 cells/ml) were incubated as in Example 6 with 0. 0, 0. 01 and 0. 1 pg/ml of 5. 0-7. 5 x 105 Da HA + 100 pg/ml of the synthetic 6 base oligonucleotide GG (GT) GG (SEQ ID NO : 1) or + 100 µg/ml of the synthetic 27 base oligonucleotide (GT) 13G (SEQ ID NO : 2) (Table 6). MTT was used at 50 µl per well.

Table 6 HA potentiation of inhibition of synthetic oligonucleotide inhibition of cell proliferation

SEQUENCES % INHIBITION 100 Rg/ml 5. 0-7. 5 x 105 Da HA 0. 0 µg/ml 0.01 µg/ml 0.1 µg/ml 0 6 5 GG (GT)1 GG- (6 bases)-SEQ ID NO : 1 20 34 33 (G, T), 3G- (27 bases)-SEQ ID NO : 2 44 51 59

As shown in Table 6, 0. 01 pg/ml HA and 0. 1 µg/ml HA potentiated the anti- neoplastic activity of 6 base GG (GT), GG (SEQ ID NO : 1) and 0. 01 pg/ml HA potentiated the antineoplastic activity of 27 base (GIT) 13G (SEQ ID NO : 2).

Example 8 HA potentiation of the anti-neoplastic effect of chemotherapeutic drugs RT-4 human bladder cancer cells and MCF-7 human breast cancer cells were incubated in as in Example 6 with 0. 0, 0. 008 or 0. 08 µg/ml of 5. 0-7. 5 x 105 Da HA + 0. 1 pLg/ml of CIS and with + 1. 0 µg/ml or + 10 pg/ml of 5-FU (Table 7).

Table 7 HA potentiation of chemotherapeutic drug inhibition of cell proliferation* % INHIBITION CELLS 0-7. 5 x 105 Da HA Saline 0. 008 llg/ml 0. 08/ml RT-4 + saline 0 0 0 RT-4+CIS at 0.1 µg/ml 2 13 15 RT-4+5-FU at 1.0 µg/ml 14 18 19 MCF-7 + saline 0 12 12 MCF-7+5-FU at 10 µg/ml 18 32 31 As shown in Table 7, 0. 008 ug/ml and 0. 08 llg/ml HA potentiated the anti-neoplastic effect of 0. 1 g/ml CIS and of 1. 0 pg/ml 5-FU on RT-4 cancer cells and the anti- neoplastic effect of 10 ug/ml of 5-FU on MCF-7 cancer cells.

Example 9 CD44 cell surface receptors and HA inhibition of proliferation CD44 is a cell surface HA receptor that has multiple variants (Screaton et al.

Proc. Natl. Acad. Sci. USA, 89 : 12160, 1992). CD44 variants are selectively expressed in human tumors and are over-expressed on numerous tumor cell lines (Naot et al. Adv. Cancer Res. 71 : 241, 1997). It has been suggested that CD44 receptors on cancer cells enables HA to deliver effective amounts of the highly lipophilic chemotherapeutic drug paclitaxel (TAXOL) into cancer cells at low paclitaxel dosage amounts because the paclitaxel binds to the HA that, in turn, binds to the CD44 receptors (PCT/CA98/00660).

To determine if HA binding to CD44 receptors correlates with inhibition of cell proliferation, CD44 receptor expression was detected by flow cytometry (FCM)

using the fluorescent anti-HA receptor monoclonal antibody FITC-CD44 (clone G44- 26 (C26), Pharmingen, Mississauga, Ontario, Canada). Briefly, cells were pelleted by centrifugation at 180 x G for 5 min at RT, washed twice in PBS and incubated with FITC-CD44 at the concentration recommended by the manufacturer for 20 min at 4° C in the dark. The cells were then washed twice in PBS by centrifugation and cell fluorescence was measured at 488 nm excitation and 530 nm emission (FL1 detector).

Data were analyzed on a FACSCALIBUR using the program CELLQUEST (Becton Dickinson, San Jose, CA, USA).

CD44 expression and the inhibition of proliferation by 5. 0-7. 5 x 105 Da HA were measured using Jurkat T cell leukemia cells ; MCF-7 human breast cancer cells ; RT-4, T-24, HT-1376 and UMUC-3 human bladder cancer cells ; and, PC-3, Du-145 and LNCaP prostate cancer cells (Table 8) Table 8 CD44 cell surface expression and HA inhibition of cell proliferation CD44 expression in mean fluorescent units 5. 0-7. 5 x 10'Da HA-80 gg/m I CELLS Unstained cells Cells + anti-CD44 % inhibition of proliferation HT-1376 200 Rut4 60 T-24 3 1800 0 UMUC-3 3 1800 2 PC-3 6 400 30 Du-145 3 450 38 MCF-7 70 35 Jurkat T 3 3 0 LNCaP 26 As shown in Table 8, expression of CD-44 receptors by cancer cells did not correlate with inhibition of proliferation by HA. PC-3 cancer cells express CD44 receptors, whereas LNCaP cancer cells do not express CD44 receptors (Lokeshwar et al.

Anticancer Res. 15 : 1191, 1995). However, as shown in Table 8, HA inhibition of proliferation of PC-3 cancer cells (30%) and of LNCaP cancer cells (26%) was not significantly different.

Example 10

Induction of cytokine production Peripheral blood mononuclear cells (hereinafter,"PBMCs") were isolated from the blood of 5 healthy humans by Ficoll-Hypaque (Amersham Pharmacia Biotech, Baie d'Urfée, Quebec, Canada) density gradient centrifugation of whole blood. Stimulation of IL-6 and IL-12 production by the immune system cells was determined using the appropriate commercial ELISA (BioSource, Camarillo, CA).

Results are expressed as the"fold" (x) increases in cytokine production by treated cells compared to control cells.

PBMCs were incubated with 1 mg/ml of 5. 0-7. 5 x 105 Da and production of IL-6 and IL-12 was determined (Table 9).

Table 9 Cytokine production Individual IL-6 IL-12 1 3. 8x 25. 2x 2 1. 8x 7. lx 3 4.1x 26.5x 4 1. 4x I O. Ox 5 6. 3x 8. 5x

As shown in the Table 9, HA stimulated both IL-6 and IL-12 production by immune system cells.

PBMCs, isolated from the blood of individual &num l, were incubated with 0. 008, 0. 04, 0. 2 and 1 mg/ml of 5. 0-7. 5 x 105 Da (Table 10) Table 10 Cytokine production 5. 0-7. 5 x 10'Da HA (mg/ml) IL-6 IL-12 0. 008 2. 4x 4. 9x 0. 040 3.5x 13/8x 0. 200 2. 9x 8. Sx 1. 0003'825. 2x

As shown in the Table 10, HA at 0. 008, 0. 04, 0. 2 and 1 mg/ml, stimulated both IL-6 and IL-12 production by immune system cells.

Example 11 <BR> <BR> <BR> Effect of saline, HA M-DCA. MCC, HA+M-DNA and HA+MCC on PC3 tumors in mice PC-3 human prostate cancer cells are implanted subcutaneously into 224 male nude BALB/c mice. The mice are divided into 28 groups of 8 mice (Table 11).

Table 11 Effect of saline. HA, M-DNA, MCC, HA+M-DNA and HA+MCC M-DNAorMCCM-DNAorMCCM-DNAorMCC Saline 0.02 mg/kg 0.2 mg/kg 2.0 mg/k Saline Group I Groups5 and 17 Groups9 and 21Groups 13 and 25 HA at 16.0 mg/kg Group 2 Groups 6 and 18 Groups 10 and 22 Groups 14 and 26 HA at 1.6 mg/kg Group 3 Groups 7 and 19 Groups 11 and 23 Groups 15 and 27 HA at 0.16 mg/kg Group 4 Groups 8 and 20 Groups12 and 24 Groups 16 and 28 Saline, HA, M-DNA, MCC, HA+M-DNA and HA+MCC are administered intravenously on day 0 and at 3-day intervals for 4 weeks (10 injections) at which time the mice are sacrificed and tumor mass and number of metastases are determined. Groups 2 to 28 mice have less tumor mass and fewer metastases than Group 1 mice. Groups 6-8, 10-12, 14-16, 18-20, 22-24 and 26-28 have less tumor mass and fewer metastases than Groups 5, 9, 13, 17, 21 and 25 mice.

Example 12 Effect of saline, HA, M-DNA. MCC, HA+M-DNA and HA+MCC on LNCaP tumors in mice LNCaP human prostate cancer cells (CD44 null) are implanted subcutaneously into 224 male nude BALB/c mice. The mice are divided into 28 groups of 8 mice (Table 412).

Table 12 Effect of saline, HA, M-DNA, MCC, HA+M-DNA and HA+MCC M-DNA or MCC M-DNA or MCC M-DNA or MCC Saline 0. 02 mg/kg 0. 2 mg/kg 2. 0 mg/kg Saline Group I Groups5 and 17 Groups9 and 21 Groups 13 and 25 HA at 16. 0 ms/kg Group 2 Groups 6 and 18 Groups and 22 Groups 14 and 26 HA at 1.6 mg/kg Group 3 Groups 7 and 19 Groups 11 and 23 Groups 15 and 27 HA at 0.16 mg/kg Group 4 Groups 8 and 20 Groups 12 and 24 Groups 16 and 28

Saline, HA, M-DNA, MCC. HA+M-DNA and HA+MCC are administered intravenously on day 0 and at 3-day intervals for 4 weeks (10 injections) at which time the mice are sacrificed and tumor mass and number of metastases are determined. Groups 2 to 28 mice have less tumor mass and fewer metastases than Group 1 mice. Groups 6-8, 10-12, 14-16, 18-20, 22-24 and 26-28 have less tumor mass and fewer metastases than Groups 5, 9, 13, 17, 21 and 25 mice. These results show that treatment outcome does not depend on CD44 expression by the cancer cells.

Example 13 Effect of saline, HA, M-DNA, MCC, HA+M-DNA and HA+MCC on Bl6Fl tumors in mice B16F1 cancer cells are implanted intravenously into 224 female C57BL/6 mice. The mice are divided into 28 groups of 8 mice (Table 13).

Table 13 Effect of saline, HA, M-DNA, MCC, HA+M-DNA and HA+MCC on B16F1 tumors M-DNAorMCCM-DNAorMCCM-DNAorMCC Saline 02 mg/kg 0. 2 mg/kg 2. 0 mg/kg Saline Group 1 Groups 5 and 17 Groups9 and 21Groups 13 and 25 HA-N at 16. 0 mg/kg Group 2 Groups 6 and 18 Groups 10 and 22 Groups 14 and 26 HA-N at 1. 6 mg/kg Group3 Groups 7 and 19 Groups l 1 and 23Groups ! 5 and 27 HA-N at 0. 16 mg/kg Group 4 Groups 8 and 20 Groups 12 and 24 Groups 16 and 28 Saline, HA, M-DNA, MCC, HA+M-DNA and HA+MCC are administered intratumorally in saline on day 0 and at 3 day intervals for 4 weeks (10 injections) at which time the mice are sacrificed and tumor mass and number of metastases are determined. Groups 2 to 28 mice have less tumor mass and fewer metastases than Group 1 mice. Groups 6-8, 10-12, 14-16, 18-20, 22-24 and 26-28 have less tumor mass and fewer metastases than Groups 5, 9, 13, 17, 21 and 25 mice.

Example 14 Effect ofsaline, HA, CIS, 5-FU, HA+ CIS and HA+ 5-FU on PC3 tumors in mice PC-3 cancer cells are implanted subcutaneously into 224 male nude BALB/c mice. The mice are divided into 28 groups of 8 mice (Table 14).

Table 14 Effect of saline, HA, CIS, 5-FU, HA+CIS and HA+5-FU on PC3 tumors CIS or5-FU CIS or5-FU CIS or5-FU Saline 0.1 mg/kg 1.0 mg/kg 1.0 mg/kg Saline Group1 Groups 5 and 17 Groups9 and 21 Group 13 and 25 HA-N at 16. 0 mg/kg Group 2 Groups 6 and 18Groups 10 and 22 Grou 14 and 26 HA-N at 1. 6 mg/kg Group3 Groups7 and 19Groups Hand 23Group 15 and 27 HA-N at 0. 16 mg/kg Group 4 Groups 8 and 20 Groups 12 and 24 Groups 16 and 28

Saline, HA, CIS, 5-FU, HA+CIS and HA+5FU are administered intravenously in saline on day 0 and at 3 day intervals for 4 weeks (10 injections) at which time the mice are sacrificed and tumor mass and number of metastases are determined. Groups 2 to 28 mice have less tumor mass and fewer metastases than Group 1 mice. Groups 6-8, 10-12, 14-16, 18-20, 22-24 and 26-28 have less tumor mass and fewer metastases than Groups 5, 9, 13, 17, 21 and 25 mice.

Example 15 Effect of saline, HA, CIS, 5-FU, HA+ CIS and HA+ 5-FU on LNCaP tumors in mice LNCaP cancer cells (CD44 null) are implanted subcutaneously into 224 male nude BALB/c mice. The mice are divided into 28 groups of 8 mice (Table 15).

Table 15 Effect of saline, HA, CIS, 5-FU, HA+CIS and HA+5-FU on LNCaP tumors CIS or5-FU CIS or5-FU CIS or5-FU Saline 0. 1 mg/kg I. 0 mg/kg 10. 0 mg/kg Saline Group I Groups 5 and 17 Groups 9 and 21 Grou 13 and 25 HA-N at 16. 0 mg/kg Group 2 Groups 6 and 18Groups ! 0 and 22 Group 14 and 26 HA-N at 1. 6 mg/kg Group 3 Groups 7 and 19Groups 11 and 23 Group 15 and 27 HA-N at 0. 16 mg/kg Group 4 Groups 8 and 20 groups 12 and 24 Groups 16 and 28 Saline, HA, CIS, 5-FU, HA+CIS and HA+5FU are administered intravenously in saline on day 0 and at 3 day intervals for 4 weeks (10 injections) at which time the mice are sacrificed and tumor mass and number of metastasis are determined. Groups 2 to 28 mice have less tumor mass and fewer metastases than Group 1 mice. Groups 6-8, 10-12, 14-16, 18-20, 22-24 and 26-28 have less tumor mass and fewer metastases

than Groups 5, 9, 13, 17, 21 and 25 mice. These results show that treatment outcome does not depend on CD44 expression by the cancer cells..

Example 16 Effect of saline, HA, CIS, 5-FU, HA+CIS and HA+S-FU on Bl6Fl tumors in mice B16F1 cancer cells are implanted subcutaneously into 224 female C57BL/6 mice. The mice are divided into 28 groups of 8 mice (Table 16).

Table 16 Effect of saline, HA, CIS, 5-FU, HA+CIS and HA+5-FU on B16F1 tumors CIS 0. 01 mg/kg CIS 0. 1 mg/kg CIS 1. 0 mg/kg or Saline or5-FUI. 0 mg/kg or5-FU 10. 0 mg5-FU 100. 0 mg/kg Saline Group I Groups 5 and 17 Groups9 and 21 Group 13 and 25 HA-N at 16. 0 mg/kg Group 2 Groups 6 and 18 Groups 10 and 22 Group 14 and 26 HA-N at 1. 6 mg/kg Group 3 Groups7 and 19Groups 11 and 23Group 15 and 27 HA-N at 0. 16 mg/kg Group 4 Groups 8 and 20Groups 12 and 24Groups 16 and 28

Saline, HA, CIS, 5-FU, HA+CIS and HA+5FU are administered intravenously in saline on day 0 and at 3 day intervals for 4 weeks (10 injections) at which time the mice are sacrificed and tumor mass and number of metastases are determined. Groups 2 to 28 mice have less tumor mass and fewer metastases than Group 1 mice.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.