The invention relates to a vaccine comprising a pappalysin and vaccine compositions comprising a pappalysin.

Pappalysin is a secreted pregnancy associated metalloproteinase of molecular weight 181 kilodaltons which naturally exists as a disulphide linked homodimer which is expressed continually during pregnancy and is found in a complex with an inhibitor protein called eosinophil major basic protein in a 2:2 proteinase:inhibitor complex. A second form of the enzyme exists as pappalysin 2 [PappA2J which has a molecular weight of 198.5 kilodaltons, functions as a monomer and is preferentially expressed in the placenta and non pregnant mammary gland with low expression in the kidney, fetal brain and pancreas. The substrates for pappalysin are insulin like growth factor binding proteins [IGFBP] of which there are 6 different proteins. IGFBP 4 and 5 are the preferred substrates for pappalysin. PappA2 cleaves IGFBP 5 preferentially. IGFBPs are found tightly bound with insulin-like growth factor [IGF-1] which inhibits IGF-1 activity. IGF-1 is a 70 amino acid polypeptide with a molecular weight of 7.6kD. IGF-1 stimulates, amongst other cells, the proliferation of chondrocytes resulting in bone growth. IGF-1 is also implicated in muscle development. IGF-1 is an example of a protein ligand that interacts with members of the receptor tyrosine kinase (RTK) superfamily. Approximately 98% of IGF-1 is bound to one of the six IGFBPs. IGFBP3 is the most abundant and accounts for 80% of IGF-1 binding. IGF-1 binds two receptors; the IGF-1 receptor (IGFR) and insulin receptor (IR) the former of which is bound with greater affinity. It is also known that IGF-1 has a role in the maintenance of tumours and therefore IGF-1 antagonists will have therapeutic value in the treatment of cancer.

In our co-pending application (WO2005/089043) we describe the isolation of prostate stem cells which have been directly isolated from lymph node and prostate glands from a series of patient samples. These stem cells express markers that characterise the cells with stem cell properties. The following markers are typically expressed as prostate stem cell markers; human epithelial antigen (HEA), CD44, high expression of α ₂ βi integrin and CD133. Furthermore, in our co-pending application (WO2007/0128110) we disclose array expression of genes that are up regulated in cancer prostate stem cells when compared to normal prostate stem cells. One of the most highly up regulated genes in the array is pappalysin. We have further analysed pappalysin expression in prostate stem cells and confirm that it is highly expressed thereby validating the array analysis disclosed in WO2007/0128110. Moreover we have analysed the expression of pappalysin in other cells and found that expression is high in prostate cancer cell lines and correlates with the degree of malignancy of the prostate cell-lines. Furthermore we disclose that the related pappalysin, pappalysin 2 is also produced by cancer cell-lines to high levels. Pappalysin and pappalysin 2 are secreted proteins with a restricted tissue/cell expression pattern providing an ideal candidate for the development of small molecule inhibitors and the like.

According to an aspect of the invention there is provided a vaccine composition comprising a pappalysin polypeptide, or antigenic part thereof, with an adjuvant and/or carrier.

In a preferred embodiment of the invention the pappalysin polypeptide is represented by the amino acid sequences in Figures 2 or Figure 4.

In a preferred embodiment of the invention said antigenic part consists of an amino acid sequence or sequence variant thereof selected from the group consisting of the amino acid sequences presented in Figure 13a, 13b, 13c, 13d, 13e or 13f, wherein said sequence variant is an amino acid addition, deletion or substitution of at least one amino acid residue and said sequence variant includes at least one antigenic epitope.

In a preferred embodiment of the invention said antigenic part consists of an amino acid sequence presented in Figure 13c.

In a preferred embodiment of the invention said antigenic part consists of an amino acid sequence or sequence variant thereof selected from the group consisting of the amino acid sequences presented in Figure 14a, 14b, 14c, 14d, 14e or 14f, wherein said sequence variant is an amino acid addition, deletion or substitution of at least one amino acid residue and said sequence variant includes at least one antigenic epitope.

In a preferred embodiment of the invention said antigenic part consists of an amino acid sequence presented in Figure 14c A variant polypeptide may differ in amino acid sequence by one or more substitutions, additions, deletions, truncations that may be present in any combination. Among preferred variants are those that vary from a reference polypeptide by conservative amino acid substitutions. Such substitutions are those that substitute a given amino acid by another amino acid of like characteristics. The following non-limiting list of amino acids are considered conservative replacements (similar): a) alanine, serine, and threonine; b) glutamic acid and aspartic acid; c) asparagine and glutamine d) arginine and lysine; e) isoleucine, leucine, methionine and valine and f) phenylalanine, tyrosine and tryptophan. Most highly preferred are variants that retain or enhance the same biological function and activity as the reference polypeptide from which it varies. In addition, the invention features polypeptide sequences having at least 50-75% identity with the polypeptide sequences as herein disclosed, or fragments and functionally equivalent polypeptides thereof. In one embodiment, the polypeptides have at least 75% identity, 85% identity, more preferably at least 90% identity, even more preferably at least 95% identity, still more preferably at least 97% identity, and most preferably at least 99% identity with the amino acid sequences illustrated herein.

The terms adjuvant and carrier are construed in the following manner. Some polypeptide or peptide antigens contain B-cell epitopes but no T cell epitopes. Immune responses can be greatly enhanced by the inclusion of a T cell epitope in the polypeptide/peptide or by the conjugation of the polypeptide/peptide to an immunogenic carrier protein such as keyhole limpet haemocyanin or tetanus toxoid which contain multiple T cell epitopes. The conjugate is taken up by antigen presenting cells, processed and presented by human leukocyte antigens (HLA's) class Il molecules. This allows T cell help to be given by T cell's specific for carrier derived epitopes to the B cell which is specific for the original antigenic polypeptide/peptide. This can lead to increase in antibody production, secretion and isotype switching. An adjuvant is a substance or procedure which augments specific immune responses to antigens by modulating the activity of immune cells. Examples of adjuvants include, Freunds adjuvant, muramyl dipeptides, liposomes, cytokines selected from the group consisting of GMCSF, interferon gamma, interferon alpha, interferon beta, interleukin 12, interleukin 23, interleukin 17, interleukin 2, interleukin 1 , TGF, TNFα, and TNFβ; and TLR agonists such as CpG oligonucleotides, flagellin, monophosphoryl lipid A, poly I:C and derivatives thereof.

A carrier is an immunogenic molecule which, when bound to a second molecule augments immune responses to the latter. According to a further aspect of the invention there is provided a DNA vaccine composition comprising a nucleic acid molecule encoding a pappalysin polypeptide or antigenic part thereof.

In a preferred embodiment of the invention said composition comprises a nucleic acid molecule selected from the group consisting of: i) a nucleic acid molecule comprising or consisting of the nucleic acid sequence as represented in Figure 1 and/or Figure 3; ii) a nucleic acid molecule the complementary strand of which hybridizes under stringent hybridization conditions to the sequences in i) above wherein said nucleic acid molecule encodes a pappalysin polypeptide or antigenic part thereof.

In a preferred embodiment of the invention said nucleic acid molecule is selected from the group consisting of:

i) a nucleic acid molecule consisting of the nucleic acid sequence as represented in Figure 11a, 1 1 b, 11c, 11d, 11 e or 11 f ; ii) a nucleic acid molecule the complementary strand of which hybridizes under stringent hybridization conditions to the sequences in i) above wherein said nucleic acid molecule encodes a pappalysin polypeptide or antigenic part thereof.

In a preferred embodiment of the invention said nucleic acid molecule consists of the nucleic acid sequence presented in Figure 11 c.

In a preferred embodiment of the invention said nucleic acid molecule is selected from the group consisting of:

i) a nucleic acid molecule consisting of the nucleic acid sequence as represented in Figure 12a, 12b, 12c, 12d, 12e or 12f; ii) a nucleic acid molecule the complementary strand of which hybridizes under stringent hybridization conditions to the sequence in i) above wherein said nucleic acid molecule encodes a pappalysin polypeptide or antigenic part thereof

In a preferred embodiment of the invention said nucleic acid molecule consists of the nucleic acid sequence presented in Figure 12c.

In a preferred embodiment of the invention said nucleic acid molecule is part of an expression vector adapted to express said pappalysin polypeptide or antigenic part thereof.

Typically said adaptation includes, the provision of transcription control sequences (promoter sequences) which mediate cell/tissue specific expression. These promoter sequences may be cell/tissue specific, inducible or constitutive.

Promoter is an art recognised term and, for the sake of clarity, includes the following features which are provided by example only, and not by way of limitation. Enhancer elements are cis acting nucleic acid sequences often found 5' to the transcription initiation site of a gene (enhancers can also be found 3' to a gene sequence or even located in intronic sequences and is therefore position independent). Enhancers function to increase the rate of transcription of the gene to which the enhancer is linked. Enhancer activity is responsive to trans acting transcription factors (polypeptides) which have been shown to bind specifically to enhancer elements. The binding/activity of transcription factors (please see Eukaryotic Transcription Factors, by David S Latchman, Academic Press Ltd, San Diego) is responsive to a number of environmental cues which include, by example and not by way of limitation, intermediary metabolites (eg glucose, lipids), environmental effectors (eg light, heat,).

Promoter elements also include so called TATA box and RNA polymerase initiation selection (RIS) sequences which function to select a site of transcription initiation. These sequences also bind polypeptides which function, inter alia, to facilitate transcription initiation selection by RNA polymerase.

Adaptations also include the provision of selectable markers and autonomous replication sequences which both facilitate the maintenance of said vector in either the eukaryotic cell or prokaryotic host. Vectors which are maintained autonomously are referred to as episomal vectors. Adaptations which facilitate the expression of vector encoded genes include the provision of transcription termination/polyadenylation sequences. This also includes the provision of internal ribosome entry sites (IRES) which function to maximise expression of vector encoded genes arranged in bicistronic or multi-cistronic expression cassettes.

Expression control sequences also include so-called Locus Control Regions (LCRs). These are regulatory elements which confer position-independent, copy number- dependent expression to linked genes when assayed as transgenic constructs in mice. LCRs include regulatory elements that insulate transgenes from the silencing effects of adjacent heterochromatin, Grosveld et al., Cell (1987), 51 : 975-985.

These adaptations are well known in the art. There is a significant amount of published literature with respect to expression vector construction and recombinant DNA techniques in general. Please see, Sambrook et al (1989) Molecular Cloning: A Laboratory Manual, Cold Spring Harbour Laboratory, Cold Spring Harbour, NY and references therein; Marston, F (1987) DNA Cloning Techniques: A Practical Approach VoI III IRL Press, Oxford UK; DNA Cloning: F M Ausubel et al, Current Protocols in Molecular Biology, John Wiley & Sons, lnc.(1994).

In a preferred embodiment of the invention said adjuvant is selected from the group consisting of: cytokines selected from the group consisting of GMCSF, interferon gamma, interferon alpha, interferon beta, interleukin 12, interleukin 23, interleukin 17, interleukin 2, interleukin 1 , TGF, TNFα, and TNFβ.

In a further alternative embodiment of the invention said adjuvant is a TLR agonist such as CpG oligonucleotides, flagellin, monophosphoryl lipid A, poly I:C and derivatives thereof.

In a preferred embodiment of the invention said adjuvant is a CpG oligonucleotide.

In a preferred embodiment of the invention said adjuvant is a bacterial cell wall derivative such as muramyl dipeptide (MDP) and/or trehelose dycorynemycolate (TDM). According to a further aspect of the invention there is provided a method to vaccinate a subject suffering from or having a predisposition to cancer comprising administering an effective amount of a vaccine composition comprising a pappalysin polypeptide or antigenic part thereof and an adjuvant and/or carrier.

As used herein, the term "cancer" refers to cells having the capacity for autonomous growth, i.e., an abnormal state or condition characterized by rapidly proliferating cell growth. The term is meant to include all types of cancerous growths or oncogenic processes, metastatic tissues or malignantly transformed cells, tissues, or organs, irrespective of histopathologic type or stage of invasiveness. The term "cancer" includes malignancies of the various organ systems, such as those affecting, for example, lung, breast, thyroid, lymphoid, gastrointestinal, and genito-urinary tract, as well as adenocarcinomas which include malignancies such as most colon cancers, renal-cell carcinoma, prostate cancer and/or testicular tumours, non-small cell carcinoma of the lung, cancer of the small intestine and cancer of the esophagus. The term "carcinoma" is art recognized and refers to malignancies of epithelial or endocrine tissues including respiratory system carcinomas, gastrointestinal system carcinomas, genitourinary system carcinomas, testicular carcinomas, breast carcinomas, prostatic carcinomas, endocrine system carcinomas, and melanomas. Exemplary carcinomas include those forming from tissue of the cervix, lung, prostate, breast, head and neck, colon and ovary. The term "carcinoma" also includes carcinosarcomas, e.g., which include malignant tumours composed of carcinomatous and sarcomatous tissues. An "adenocarcinoma" refers to a carcinoma derived from glandular tissue or in which the tumor cells form recognizable glandular structures. The term "sarcoma" is art recognized and refers to malignant tumors of mesenchymal derivation.

In a preferred method of the invention said cancer is prostate cancer.

In an alternative preferred method of the invention said cancer is lung cancer.

According to a further aspect of the invention there is provided a nucleic acid molecule consisting of a nucleic acid sequence selected from the group consisting of:

(i) a nucleic acid molecule consisting of the nucleic acid sequence as represented in Figure 11 a, 11 b, 11c, 11d, 11e or 11f; (ii) a nucleic acid molecule the complementary strand of which hybridizes under stringent hybridization conditions to the sequences in i) above wherein said nucleic acid molecule encodes a pappalysin polypeptide or antigenic part thereof; and

(iii) a nucleic acid molecule comprising nucleotide sequences that are degenerate as a result of the genetic code to the nucleotide sequence defined in (i) and (ii).

According to a further aspect of the invention there is provided a nucleic acid molecule consisting of a nucleic acid sequence selected from the group consisting of:

(i) a nucleic acid molecule consisting of the nucleic acid sequence as represented in Figure 12a, 12b, 12c, 12d, 12e or 12f;

(ii) a nucleic acid molecule the complementary strand of which hybridizes under stringent hybridization conditions to the sequences in i) above wherein said nucleic acid molecule encodes a pappalysin polypeptide or antigenic part thereof; and (iii) a nucleic acid molecule comprising nucleotide sequences that are degenerate as a result of the genetic code to the nucleotide sequence defined in (i) and (ii).

According to a further aspect of the invention there is provided a polypeptide encoded by a nucleic acid molecule according to the invention.

In a preferred embodiment of the invention said polypeptide is a variant polypeptide and comprises the amino acid sequence represented in Figure 13a, 13b, 13c, 13d, 13e or 13f, which sequence has been modified by deletion, addition or substitution of at least one amino acid residue.

In a preferred embodiment of the invention said polypeptide consists of the amino acid sequence as represented in Figures 13a, 13b, 13c, 13d, 13e or 13f.

In a preferred embodiment of the invention said polypeptide consists of the amino acid sequence as represented in Figures 13c.

In a preferred embodiment of the invention said polypeptide is a variant polypeptide and comprises the amino acid sequence represented in Figures 14a, 14b, 14c, 14d, 14e or 14f, which sequence has been modified by deletion, addition or substitution of at least one amino acid residue. In a preferred embodiment of the invention said polypeptide consists of the amino acid sequence as represented in Figures 14a, 14b, 14c, 14d, 14e or 14f.

In a preferred embodiment of the invention said polypeptide consists of the amino acid sequence as represented in Figures 14c.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

An embodiment of the invention will now be described by example only and with reference to the following figures:

Figure 1 is the nucleic acid sequence of human pappalysin;

Figure 2 is the amino acid sequence of human pappalysin;

Figure 3 is the nucleic acid sequence of human pappalysin 2;

Figure 4 is the amino acid sequence of human pappalysin 2;

Figure 5 illustrates immunofluoresence of pappalysin in prostate cell-lines PNT 2, P4E6 and PC3; Figure 6 illustrates immunofluoresence of pappalysin in primary BPH cells; and

Figure 7 illustrates immunofluoresence of pappalysin in primary cancer cells;

Figure 8 illustrates immunofluoresence of pappalysin 2 in cell-lines PNT 2, P4E6 and PC3;

Figure 9 is a comparison of pappalysin expression using RT PCR with levels of expression predicted from array analysis;

Figure 10 is a schematic representation of pappalysin and domains 1-6 from which DNA and immunogenic protein fragments are derived;

Figure 11 a is the nucleotide sequence of mouse pappalysin 1 fragment 1 ; Figure 11 b is the nucleotide sequence of mouse pappalysin 1 fragment 2; Figure 1 1 c is the nucleotide sequence of mouse pappalysin 1 fragment 3; Figure 11d is the nucleotide sequence of mouse pappalysin 1 fragment 4; Figure 11e is the nucleotide sequence of mouse pappalysin 1 fragment 5; Figure 11f is the nucleotide sequence of mouse pappalysin 1 fragment 6;

Figure 12a is the nucleotide sequence of human pappalysin 1 fragment 1 ; Figure 12b is the nucleotide sequence of human pappalysin 1 fragment 2; Figure 12c is the nucleotide sequence of human pappalysin 1 fragment 3; Figure 12d is the nucleotide sequence of human pappalysin 1 fragment 4; Figure 12e is the nucleotide sequence of human pappalysin 1 fragment 5; Figure 12f is the nucleotide sequence of human pappalysin 1 fragment 6;

Figure 13a is the amino acid sequence of mouse pappalysin 1 fragment 1 ; Figure 13b is the amino acid sequence of mouse pappalysin 1 fragment 2; Figure 13c is the amino acid sequence of mouse pappalysin 1 fragment 3; Figure 13d is the amino acid sequence of mouse pappalysin 1 fragment 4; Figure 13e is the amino acid sequence of mouse pappalysin 1 fragment 5; Figure 13f is the amino acid sequence of mouse pappalysin 1 fragment 6;

Figure 14a is the amino acid sequence of human pappalysin 1 fragment 1 ; Figure 14b is the amino acid sequence of human pappalysin 1 fragment 2; Figure 14c is the amino acid sequence of human pappalysin 1 fragment 3; Figure 14d is the amino acid sequence of human pappalysin 1 fragment 4; Figure 14e is the amino acid sequence of human pappalysin 1 fragment 5; Figure 14f is the amino acid sequence of human pappalysin 1 fragment 6;

Figure 15 shows pappalysin expression in stable transfectants of B16 cells. Expression was measured by RT-PCR in 4 stable clones after 6 passages (lanes 2-5) or >20 passages in continuous culture (lanes 6-9). The parental B16 cells were shown to be pappalysin negative (lane 1). The pappalysin expression plasmid was amplified as a positive control (lane 10), water was used as a negative control (lane 11)

Figure 16 shows SDS-PAGE analysis of purified protein fragments. Eluted fractions from the purification column were subjected to SDS-PAGE analysis to determine recovery of the desired product and the presence of any contaminating proteins (fractions). Aliquots of uninduced (U) and induced (I) bacterial cultures are shown to indicate that expression was induced. Flow-through (F) and wash (W) samples were also analysed to detect any protein loss during the protein purification procedure.

Materials and Methods

Tissue collection, isolation, and culture of tumor stem cells

Human prostatic tissue was obtained, with patient consent, from patients undergoing radical prostatectomy for prostate cancer. Prostate cancer was confirmed by histologic examination of representative adjacent fragments. In some cases, lymph node biopsies were taken if metastasis was suspected. Primary stem cell derived cultures were maintained in complete keratinocyte growth medium [keratinocyte serum-free medium with epidermal growth factor (EGF) and bovine pituitary extract; Invitrogen, Paisley, Scotland]. The medium was also supplemented with 2 ng/mL of leukaemia inhibitory factor (LIF; Sigma, Poole, United Kingdom), 2 ng/mL of stem cell factor (Sigma), and

100 ng/mL of cholera toxin (Sigma). CD44/C-2 βi ^'/CD133 ⁺ cells were isolated from the tissue, as described previously for normal prostate epithelium (Richardson et al, 2004). Tissue culture of standard cell lines

Cell lines were maintained at 37 ^° C / 5% CO ₂ in air in the following growth media: PNT2 R10 medium: RPMI 1640 medium (Invitrogen) containing 10% fetal calf serum and 1% L-glutamine (Invitrogen); PC3 cells H7 medium: HAMS F12 containing 7% fetal calf serum and 1 % L-glutamine supplemented with bovine pituitary extract (BPE) and epidermal growth factor (EGF); P4E6 cells K2 medium: KSFM containing 2% fetal calf serum and 1% L-Glutamine. c<2β- _| /CD133 ⁺ cells were selected directly from cultured cells from tumors before processing for imaging under confocal microscopy by fixation in ice-cold 2:1 methanol: acetone for 20 minutes. Slides were blocked for 1 hour at room temperature in 20% normal goat serum (NGS). After blocking cells were incubated with a rabbit polyclonal antibody to pappalysin A (ab59088, Abeam) diluted in 20% NGS. After washing (3x TBS), cells were further probed with an alexa488-tagged secondary antibody. Cells were mounted in the antiphotobleaching (Dako) medium under coverslips.

Cloning of mouse PAPPA fragments into pET22b(+) expression vector

Primers were designed to amplify products approximately corresponding to the predicted protein domains of human PAPPA (see figure 2 and table 1). Each forward and reverse primer also contained a 15bp sequence homologous to the BamH1 site of the His- tagged protein expression vector pET-22b(+) for use in the In-Fusion cloning system (Clontech - see below). PCR was carried using KOD Hot Start DNA polymerase (Novagen) using the following conditions: 95°C for 2mins followed 25 cycles of 95 ⁰ C 10secs, 55 ⁰ C 10secs, 70 ⁰ C 15secs. Products were run on 1 % agarose gel containing 1/10,000 dilution of GelRed (Invitrogen). Bands were visualized using a UV transilluminator (GeneGenius).

pET-22b(+) was linearized with BamH1 (37 ⁰ C, 3h) and products run on a 0.8% agarose gel stained with GelRed. A band corresponding to linearized vector was excised and the DNA purified using a Qiagen Gel Extraction kit following the manufacturer's protocol.

Insertion of the fragment DNA into the vector was accomplished using the Clontech In- Fusion Advantage kit following manufacturer's instructions. The resulting constructs were transformed into DH5α competent bacteria followed by culture on Luria broth (LB) agar containing ampicillin (50ug/ml; Sigma). Plates were incubated overnight at 37°C. Individual colonies were picked into 5ml LB containing ampicillin and incubated overnight in a shaker incubator. DNA was extracted using a Qiaprep Spin Miniprep kit (Qiagen) following manufacturer's instructions. DNA sequencing confirmed that the insert was in frame with the His tag required for purification (Technology Facility, University of York) The construct was transformed into Rosetta-gami2 (DE3) pLysS expression hosts.

Induction of protein expression

Bulk inductions were carried out using the same conditions as described above. Rosetta- gami2 (DE3) pLysS cells containing the relevant pappalysin fragment were inoculated into 10ml LB with ampicillin (50ug/ml; Sigma) and incubated at 37°C in a shaker incubator. When the OD ₆₀₀ reached 0.5, the culture was added to 500ml of LB containing ampicillin. When the OD600 reached 0.5 units 1 mM IPTG was added and the culture incubated for a further 2 hours. Cells were pelleted by centrifugation, resuspended in a wash buffer (Tris HCl 5OmM; EDTA 2mM, NaCI 5OmM pH 7.9) and pelleted once more. Dry pellets were stored at -8O ⁰ C until purification.

Purification under denaturing conditions

Preliminary experiments showed that the fragments were packaged into insoluble inclusion bodies, therefore, fragments were purified under denaturing conditions. Bacterial cell pellets from 500ml cultures were resuspended in 10ml PBS followed by sonication on ice (Soniprep 150, MSE; 4 x 30 sec. bursts interspersed with 15 sec. cooling). Lysed culture was spun at 10,000xg for 15 minutes. The supernatant was discarded and the pellet of insoluble material was resuspended in 10ml of PBS and centrifuged once more,

The resulting pellet was resuspended in a guanidine lsyis buffer. Initially the pellet was resuspended in 5ml resuspension buffer (sodium dihydrogen orthophosphate 2OmM; NaCI 0.5M pH 7.8) and 15ml of guanidine lysis buffer added (sodium dihydrogen orthophosphate 2OmM; NaCI 0.5M, guanidine HCI 8M ph7.8) resulting in a final concentration of guanidine HCI of 6M. The solubilised protein was incubated at room temperature on a rotating shaker for 10 minutes followed by filtration through a 0.8μm syringe filter. Purification was carried out using a 1ml HisTrap column (GE Healthcare) charged with 3% Ni SO ₄ attached to a AKTA purifier (Amersham). The solubilised protein was passed over the column at a rate of 1 ml/min with a denaturing binding buffer (sodium dihydrogen orthophosphate 2OmM; NaCI 0.5M, Urea 8M pH7.8). The column was washed using a denaturing wash buffer (sodium dihydrogen orthophosphate 2OmM; NaCI 0.5M, Urea 8M pH6) which was gradually replaced by native wash buffer (sodium dihydrogen orthophosphate 25mM; NaCI 0.5M, imidazole 5mM pH 8) over a 30 mins period. A linear elution was carried out by exchanging the native wash buffer with a native elution buffer (sodium dihydrogen orthophosphate 25mM; NaCI 0.5M, imidazole 50OmM pH 8) over 15 minutes such that a gradient of 5mM to 50OmM imididazole was created over time. 1 ml fractions were collected from the elution at 1 minute intervals.

Buffer exchange and concentration of protein After PAGE analysis of the eluted fragments, fractions with high expression were selected for buffer exchange into PBS and further concentration. Fractions were pooled and placed in a Vivaspin 20. PBS was added to make the volume up to 20ml followed by centrifugation at 4000 rpm until the volume was reduced to 5ml. PBS was added to 20ml and the process repeated twice more. Finally the he volume was further reduced to 1 ml. Protein concentration was quantified using a Nanodrop spectrophotometer.

Culture of B16 cells

B16 mouse melanoma cells were maintained in R10 growth medium which is comprised of RPM11640 medium supplemented with 10% foetal calf serum (PAA Laboratories Ltd. Yeovil, UK) and 1% L-Glutamine (Invitrogen, Paisley, UK).

Stable transfection of B16 cells

B16 cells were plated in 25cm ² flasks at 5 x 10 ⁵ cells/flask and incubated at 37°C in R10 growth medium for 24h prior to transfection. Cells were transfected with 6.5μg/flask of the pLNCX-PAPPA expression vector using Oligofectamine liposome transfection reagent according to the manufacturer's instructions (Invitrogen, Paisley, UK). Briefly, DNA was mixed with OptiMEM transfection medium (Invitrogen, Paisley, UK). In order to select stable transfectants growth media was changed to R10 + 600μg/ml G418 72h after transfection. Selection was maintained for 10-14 days to allow the growth of G418 resistant colonies. The cells were then re-plated at one cell/well in 96-well tissue culture plates and maintained in R10 + 600μg/ml G418. Example

Pappalysin expression is consistently cytoplasmic in all three cell lines tested; see Figures 5, 6 and 7. This is normal for a secreted protein since the secreted component cannot be detected using this technique. Expression is higher in the cancer cell lies (P4E6 and PC3) than the benign cell line (PNT2). Interestingly pappalysin expression is higher in the early stage cancer line P4E6 than the advanced stage cell line PC3 which was derived from a bone metastasis. In primary cells expression is higher on average in cancer cells compared to benign. In the cancer patient expression is higher in the α2β1high/CD133+ stem cell and α2β1high/CD133- progenitor cell populations compared to the more differentiated α2β1 low population. A similar immunofluoresence staining pattern with respect to pappalysin 2 is shown by P4E6, PC3 and PNT2 cells, see figure 8.

The stable B16 melanoma cell transfectants are used in an in vivo model to test the efficacy of vaccines disclosed herein. Expression of pappalysin in cloned cell lines is shown in Figure 15. Figure 16 describes the recombinant expression of selected pappalysin fragments 2, 3 and 4 which are described in Figure 10.