GENE EXPRESSION PROFILING IN PRIMARY OVARIAN SEROUS PAPILLARY TUMORS AND NORMAL OVARIAN EPITHELIUM

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to the field of cancer research. More specifically, the present invention relates to gene expression profiling between primary ovarian serous papillary tumors and normal ovarian epithelium.

Description of the Related Art

Ovarian carcinoma remains the cancer with the highest mortality rate among gynecological malignancies with 25,400 new cancer cases estimated in 2003 in the United States alone. Ovarian serous papillary cancer (OSPC) represents the most common histological type of ovarian carcinoma ranging from 45 to 60% of all epithelial ovarian tumors. Because of the insidious onset of the disease and the lack of reliable screening tests, two thirds of patients have advanced disease when diagnosed, and although many patients with disseminated tumors respond initially to standard combinations of surgical and cytotoxic therapy, nearly 90 percent will develop recurrence and inevitably succumb to their disease. Understanding the molecular basis of ovarian serous papillary cancer may have the potential to significantly refine diagnosis and management of these serous tumors, and may eventually lead to the development of novel, more specific and more effective treatment modalities. cDNA microarray technology has recently been used to identify genes involved in ovarian carcinogenesis. Gene expression fingerprints representing large numbers of genes may allow precise and accurate grouping of human tumors and may have the potential to identify patients who are unlikely to be cured by conventional therapy. Consistent with this view, evidence has been provided to support the notion that poor prognosis B cell lymphomas and biologically aggressive breast and ovarian carcinomas can be readily separated into different groups based on gene expression profiles. In addition, large scale gene expression analysis have the potential to identify a number of differentially expressed genes in ovarian serous papillary tumor cells compare to normal ovarian epithelial cells and may therefore lay the groundwork for future studies testing some of these markers for clinical utility in the diagnosis and, eventually, the treatment of ovarian serous papillary cancer.

Because of the lack of an effective ovarian cancer screening program and the common development of chemotherapy resistant disease after an initial response to cytotoxic agents (i.e., platinum based regimen), ovarian cancer remains the most lethal among the gynecologic malignancies. Thus, the identification of novel ovarian tumor markers to be used for early detection of the disease as well as the development of effective therapy against chemotherapy resistant/recurrent ovarian cancer remains a high priority.

The prior art is deficient in understanding the molecular differences between ovarian serous papillary cancer cells and normal ovarian epithelium and also lacks effective therapy against chemotherapy resistant/recurrent ovarian cancer. The present invention fulfills this need in the art by providing gene expression profiling for these two types of tissues and thereby providing specific proteins that may be targeted to develop effective therapeutic agents against ovarian cancer.

SUMMARY OF THE INVENTION

The present invention identifies genes with a differential pattern of expression between ovarian serous papillary carcinomas (OSPC) and normal ovarian epithelium and uses this knowledge to develop novel diagnostic and therapeutic marker for the treatment of this disease. Oligonucleotide microarrays with probe sets complementary to 12,533 genes were used to analyze gene expression profiles of ten primary ovarian serous papillary carcinomas cell lines, two established ovarian serous papillary cancer cell lines (i.e., UCI-101, UCT-107) and five primary normal ovarian epithelium cultures (NOVA). Unsupervised analysis of gene expression data identified 129 and 170 genes that exhibited > 5-fold up-regulation and down- regulation respectively in primary ovarian serous papillary carcinomas compared to normal ovarian epithelium. Genes overexpressed in established ovarian serous papillary carcinomas cell lines were found to have little correlation to those overexpressed in primary ovarian serous papillary carcinomas, highligthing the divergence of gene expression that occur as the result of long-term in vitro growth.

Hierarchial clustering of the expression data readily distinguished normal tissue from primary ovarian serous papillary carcinomas. Laminin, claudin 3 and claudin 4, tumor -associated calcium signal transducer 1 and 2 (TROP-J IEp-CAM; TROP-2), ladinin I, S100A2, SERPI N2 (PA1-2), CD24, Upocalin 2, osteopontin, kallikrein 6 (protease M) and kallikrein JO, matriptase (TADG-15) and stratifin were found among the most highly overexpressed gene in ovarian serous papillary carcinomas compared to normal ovarian epithelium. Down-regulated genes in ovarian serous papillary carcinomas included transforming growth factor beta receptor III, platelet-derived growth factor receptor alpha, SEMACAP3, ras homolog gene family member I (ARHI), thrombospondin 2 and disabled- 2/differentially expressed in ovarian carcinoma 2 (Dab2/DOC2). Differential expression of

some of these genes including claudin 3 and claudin 4, TROP-I and CD24 was validated by quantitative RT-PCR as well as by flow cytometry. Immunohistochemical staining of formalin fixed paraffin embedded tumor specimens from which primary ovarian serous papillary carcinomas cultures were derived further confirmed differential expression of CD24 and TROP- 1/Ep-CAM markers on ovarian serous papillary carcinomas vs normal ovarian epithelium. These results, obtained from highly purified primary cultures of ovarian cancer, highlight important molecular features of ovarian serous papillary carcinomas and provide a foundation for the development of new type-specific therapies against this disease. For example, a therapeutic strategy targeting TROP- 1/Ep-CAM by monoclonal chimeric/humanized antibodies may be beneficial in patients harboring chemotherapy-resistant ovarian serous papillary carcinomas.

The present invention is drawn to a method of detecting ovarian serous papillary carcinoma based on overexpression of a group of genes listed in Table 2.

In another embodiment, the present invention provides a method of detecting ovarian serous papillary carcinoma based on down-regulation of a group of genes listed in Table 3.

In another embodiment, the present invention provides a method of treating ovarian serous papillary carcinoma by inhibiting the expression and function of tumor- associated calcium signal transducer 1 (TROP-I /Ep-CAM) gene. In another embodiment, the present invention provides a method of treating ovarian serous papillary carcinoma by delivering Clostridium perfringens enterotoxins to ovarian tumor cells overexpressing claudin 3 or claudin 4 protein.

Other and further aspects, features, and advantages of the present invention will be apparent from the following description of the presently preferred embodiments of the invention. These embodiments are given for the purpose of disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows hierarchical clustering of 15 primary ovarian cell lines (i.e., 10 ovarian serous papillary carcinomas lines and 5 normal ovarian epithelial cell lines) and two established ovarian serous papillary carcinomas cell lines (i.e., UCI-101 and UCI-107).

Figure 2 shows molecular profile of 10 primary ovarian serous papillary carcinomas cell lines and 5 normal ovarian epithelial cell lines. Hierarchical clustering of 299 genes uses a 5-fold threshold (P < 0.05). The cluster is color coded using red for up- regulation, green for down-regulation, and black for median expression. Agglomerative clustering of genes was illustrated with dendrograms.

Figure 3 shows quantitative real-time PCR and microarray expression analysis of TROP-J, CD24, claudin-3 and claudin-4 genes differentially expressed between ovarian serous papillary carcinomas cells and normal ovarian epithelial cells.

Figure 4 shows representative FACS analysis of CD24 staining (left panel) and TROP- 1/Ep-CAM staining (right panel) of 2 primary ovarian serous papillary carcinomas cell lines and 1 normal ovarian epithelial cell lines. Data with CD24 and TROP-1/Ep-CAM are shown in solid black while isotype control mAb profiles are shown in white. Both CD24 and TROP-I /Ep-CAM expression were significantly higher on ovarian serous papillary carcinomas cell lines compared to normal ovarian epithelial cell lines Qx 0.001 by student t test).

Figure S shows representative immunohistochemical staining for CD24 (left panel) and Trop-1 /Ep-CAM (right panel) on 2 paraffin-embedded ovarian serous papillary carcinomas (OSPC) cell lines and 1 normal ovarian epithelial cell (NOVA) specimen. NOVAl (upper panel right and left) showed negative or light (1+) staining for both CD24 and Trop-1/Ep-CAM while OSPC 1 and OSPC 3 showed heavy apical membranous staining for CD24 (left panel) and strong membranous staining for TROP-I /Ep-CAM (right panel). Original magnification 400X.

Figures 6A-6B show qRT-PCR analysis of claudin-3 (Figure 6A) and claudin-4 (Figure 6B) expression. Y-axis, fold induction relative to normal ovary expression. X-axis, each sample tested for claudin-3 and claudin-4. For both panels, thehe first 15 columns are normal ovarian epithelium (1-3), normal endometrial epithelium (4-6), normal cervical keratinocytes (7), primary squamous cervical cancer cell lines (8-10), primary adenocarcinoma cervical cancer cell lines (11-13), Epstein-Barr transformed B lymphocytes (LCL; 14), and human fibroblasts (15). The following 16 columns are primary ovarian cancer cell lines (16- 21, serous papillary ovarian cancers; 22-26, clear cell ovarian tumors) and established serous ovarian cancer cell lines (27-31 ; i.e., UCI 101, UCI 107, CaOV3, OVACAR-3, and OVARK-

5).

Figures 7A-7D show qRT-PCR analysis of claudin-3 and claudin-4 expression in chemotherapy-naive (Figures 7A-7B) versus chemotherapy-resistant/recurrent ovarian cancer (Figures 7C-7D). Y-axis, fold induction relative to normal ovary expression. X-axis, each sample tested for claudin-3 and claudin-4. Top panels, chemotherapy-naive ovarian cancers = 6 OSPC samples ( 1); columns, mean; bars, SE; chemotherapy- resistant/recurrent ovarian cancer = 6 OSPC samples (2); columns, mean; bars, SE; P < 0.05. Bottom panels, 1 (chemotherapy naive) and 2 (chemotherapy resistant) represent claudin-3 and claudin-4 expression in autologous matched OVA-I tumors. 3 (chemotherapy naive) and 4 (chemotherapy resistant) represent claudin-3 and claudin^ expression in autologous matched OVA-4 tumors. 5 (chemotherapy naive) and 6 (chemotherapy resistant) represent claudin-3 and claudin-4 expression in autologous matched OVA-6 tumors.

Figures 8A-8B show representative immunohistochemical staining for claudin-4 on OVA-I paraffin-embedded OSPC specimens (Figure 8A) and NOVA 1 specimen (Figure 8B). NOVA 1 showed light membrane staining for claudin-4, whereas

OVA-I showed heavy cytoplasmic and membranous staining for claudin-4. Original magnification, 40Ox.

Figure 9 shows representative dose-dependent CPE-mediated cytotoxicity of primary ovarian cancers compared with positive control Vero cells or negative controls, i.e., normal and neoplastic cells, after 24 hours exposure to CPE. VERO, positive control cells. OVA-I to OVA-6, primary ovarian tumors. OVARK-5, CaOV3, and OVACAR-3, established serous ovarian tumors. Norm CX, normal cervix keratinocytes. Fibroblast, normal human fibroblasts. LCL, lymphoblastoid B cells. PBL, normal peripheral blood lymphocytes. CXl-3, primary squamous cervical cancer. ADX1-3, primary adenocarcinoma cervical cancer.

Figures 10A- 1OB show survival of C.B-17/SCID mice after i.p. injection of 5 x 10 ⁶ to 7.5 x 10 ⁶ viable OVA-I tumor cells. Animals harboring 4-week (Figure 10A) and 1- week (Figure 10B) established OVA-I tumors were injected i.p. with doses of CPE ranging from 5 to 8.5 mg. CPE was administered i.p. every 72 hours until death or end of study. Mice were evaluated on a daily basis and sacrificed when moribund. In both studies, the log-rank test yielded P < 0.0001 for the differences in survival.

DETAILED DESCRIPTION OF THE INVENTION

High-throughput technologies for assaying gene expression, such as high- density oligonucleotide and cDNA microarrays, may offer the potential to identify clinically relevant gene highly differentially expressed between ovarian tumors and normal control ovarian epithelial cells. This report discloses a genome-wide examination of differential gene expression between primary ovarian serous papillary carcinomas and normal ovarian epithelial cells (NOVA). Short-term primary ovarian serous papillary carcinomas and normal ovarian epithelial cells cultures were used to minimize the risk of a selection bias inherent in any long term in vitro growth. In the present invention, only the cancer cells derived from papillary serous histology tumors, which is the most common histological type of ovarian cancer, were included to limit the complexity of gene expression analysis.

Hierarchical clustering of the samples and gene expression levels within the samples led to the unambiguous separation of ovarian serous papillary carcinomas from normal ovarian epithelial cells. Of interest, the expression patterns detected in primary ovarian serous papillary carcinomas cells were consistently different from those seen in established serous papillary ovarian carcinoma cell lines (i.e., UCI-101 and UCI-107). These data thus highlight the divergence of gene expression that occur as a result of long-term in vitro growth.

Furthermore, these data emphasize that although established ovarian cancer cell lines provide a relatively simple model to examine gene expression, primary ovarian serous papillary carcinomas and normal ovarian epithelial cells cultures represent better model systems for comparative gene expression analysis. Because of these results, the present invention was limited to analysis of differential gene expression between the two homogeneous groups of primary ovarian serous papillary carcinomas and normal ovarian epithelial cells.

The present invention detected 298 genes that have at least five-fold difference in expression levels between ovarian serous papillary carcinomas and normal ovarian epithelial cells. The known function of some of these genes may provide insight into the biology of serous ovarian tumors while others may prove to be useful diagnostic and therapeutic markers against ovarian serous papillary carcinomas.

Laminin gamma 2

Laminin gamma 2 gene was found to be the most highly differentially expressed gene in ovarian serous papillary carcinomas with over 46-fold up-regulation relative to normal ovarian epithelial cells. Cell migration of ovarian tumor cells is considered essential for cell dissemination and invasion of the submesothelial extracellular matrix commonly seen in ovarian cancer. The laminin gamma 2 isoform has been previously suggested to play an important role in tumor cell adhesion, migration, and scattering of ovarian carcinoma cells. Thus, in agreement with recent reports in other human tumor, it is likely that high laminin expression by ovarian tumor cells may be a marker correlated with the invasive potential of ovarian serous papillary carcinomas. Consistent with this view, increased cell surface expression of laminin was found in highly metastatic tumors cells compared to cells of low metastatic potential. Importantly, previous work has shown that attachment and metastases of tumor cells can be inhibited by incubation with anti-laminin antibodies or synthetic laminin peptides.

TROP-J/Ep-CAM

TROP- l/Ep-CAM (also called 17-1 A, ESA, EGP40) is a 40 kDa epithelial transmemebrane glycoprotein found to be overexpressed in normal epithelia cells and in various carcinomas including colorectal and breast cancer. In most adult epithelial tissues, enhanced expression of Ep-CAM is closely associated with either benign or malignant proliferation. Because among mammals Ep-CAM is an evolutionary highly conserved molecule, this seem to suggest an important biologic function of this molecule in epithelial cells and tissue. In this regard, Ep-CAM is known to function as an intercellular adhesion molecule and could have a role in tumor metastasis. Because a randomized phase II trial with mAb CO17-1 A in colorectal carcinoma patients has demonstrated a significant decrease in recurrence and mortality in mAb-treated patients versus control patients, TROP- l/Ep-CAM

antigen has attracted substantial attention as a target for immunotherapy for treating human carcinomas. Importantly, data disclosed herein showed that TROP-I /Ep-CAM was overexpressed 39-folds in ovarian serous papillary carcinomas compared to normal ovarian epithelial cells. These data provide support for the notion that anti-Ep-CAM antibody therapy may be a novel, and potentially effective treatment option for ovarian serous papillary carcinomas patients with residual/resistant disease after surgical and cytotoxic therapy. Protein expression data obtained by flow cytometry on primary ovarian serous papillary carcinomas cell lines and by immunohistochemistry on uncultured ovarian serous papillary carcinomas blocks support this view.

Claudin 3 And Claudin 4

Claudin 3 and claudin 4, two members of claudin family of tight junction proteins, were two of the top five differentially expressed genes in ovarian serous papillary carcinomas. These results are consistent with a previous report on gene expression in ovarian cancer. Although the function of claudin proteins in ovarian cancer is still unclear, these proteins likely represent a transmembrane receptor. Of interest, claudin-3 and claudin 4 are homologous to CPE-R, the low and high-affinity intestinal epthelial receptor for Clostridium Perfringens enterotoxin (CPE), respectively, and are sufficient to mediate Clostridium Perfringens enterotoxin binding and trigger subsequent toxin-mediated cytolysis. These known functions of claudin-3 and claudin-4, combined with their extremely high level of expression in ovarian serous papillary carcinomas suggest a potential use of Clostridium Perfringens enterotoxin (CPE) as a novel therapeutic strategy for the treatment of chemotherapy resistant disease in ovarian cancer patients. Supporting this view, functional cytotoxicity of Clostridium Perfringens enterotoxin in metastatic androgen-independent prostate cancer overexpressing claudin-3 has recently been reported.

The instant invention discloses that 100% of the primary ovarian tumors examined overexpress one or both CPE receptors. Importantly, chemotherapy- resistant/recurrent ovarian tumors were found to express claudin-3 and claudin-4 genes at significantly higher levels when compared with chemotherapy-naive ovarian cancers. All ovarian tumors, irrespective of their resistance to chemotherapeutic agents were shown to die within 24 hours of exposure to 3.3 mg/ml CPE in vitro. The instant invention further discloses that repeated i.p. administration of CPE had a significant inhibitory effect on tumor progression and extended survival of mice harboring large ovarian tumor burdens.

Plasminogen Activator Inhibitor-2 (PA1-2)

Plasminogen activator inhibitor-2 (PAI-2), a gene whose expression has been linked to cell invasion in several human malignancies as well as to protection from tumor necrosis factor-a (TNF-a)-mediated apoptosis, was overexpressed 12-folds in ovarian serous

papillary carcinomas compared to normal ovarian epithelial cells. Previous studies have shown that elevated levels of plasminogen activator inhibitor-2 are detectable in the ascites of ovarian cancer patients and that high plasminogen activator inhibitor-2 levels are independently predictive of a poor disease-free survial. Interestingly, in some of these studies, a 7-fold increase in plasminogen activator inhibitor-2 content was found in the omentum of ovarian cancer patients compared to the primary disease suggesting that metastatic tumors may overexpressed plasminogen activator inhibitor-2. Other studies, however, have identified plasminogen activator inhibitor-2 production as a favorable prognostic factor in epithelial ovarian cancer. Indeed, high PAI-2 expression in invasive ovarian tumors was limited to a group of ovarian serous papillary carcinomas patients who experience a more prolonged disease free and overall survival. The reason of these differences are not clear, but, as previously suggested, they may be related at least in part to the actions of macrophage colony stimulating factor- 1 (CSF-I), a cytokine which has been shown to stimulate the release of PAI-2 by ovarian cancer cells.

CD24

CD24 is a small heavily glycosylated glycosylphosphatidylinositol-linked cell surface protein expressed in hematological malignancies as well as in a large variety of solid tumors. However, it is only recently that CD24 expression has been reported at RNA level in ovarian cancer. Consistent with this recent report, the present study shows that CD24 gene was overexpressed 14-folds in ovarian serous papillary carcinomas compared to normal ovarian epithelial cells. Because CD24 is a ligand of P-selectin, an adhesion receptor on activated endothelial cells and platelets, its expression may contribute to the metastatic capacities of CD24-expressing ovarian tumor cells. Importantly, because CD24 expression has been reported as an independent prognostic marker for ovarian cancer patients survival, it is likely that this marker delineating aggressive ovarian cancer disease may have therapeutic and/or diagnostic potential.

Lipocalin-2 Among the overexpressed genes identified herein, lipocalin 2 has not been previously linked to ovarian cancer. Lipocalin-2 represents a particularly interesting marker because of several features. Lipocalins are extracellular carriers of lipophilic molecules such as retinoids, steroids, and fatty acid, all of which may play important roles in the regulation of epithelial cells growth. In addition, because lipocalin is a secreted protein, it may play a role in the regulation of cell proliferation and survival. Of interest, two recent publications on gene expression profile of breast and pancreatic cancer have proposed lipocalin-2 as a novel therapeutic and diagnostic marker for prevention and treatment of these diseases. On the basis

of the data disclosed herein, lipocalin 2 may be added to the known markers for ovarian cancer.

Osteopontin (SPPl )

Osteopontin (SPPl) is an acidic, calcium-binding glycophosphoprotein that has recently been linked to tumorigeneis in several experimental animal models and human patients studies. Because of its integrin-binding arginine-glycine-aspartate (RDG) domain and adhesive properties, osteopontin has been reported to play a crucial role in the metastatic process of several human tumors. However, it is only recently that upregulated expression of osteopontin in ovarian cancer has been identified. Importantly, because of the secreted nature of this protein, osteopontin has been proposed as a novel biomarkers for the early recognition of ovarian cancer. In the data disclosed herein, SPPJ gene was overexpressed 10-folds in ovarian serous papillary carcinomas compared to normal ovarian epithelial cells. Taken together, these data confirm a high expression of osteopontin in ovarian serous papillary carcinomas and it is of interest to further assess its clinical usefulness in ovarian cancer.

Kallikreins

The organization of kallikreins, a gene family consisting of 15 genes that all encode for trypsin-like or chymotrypsin-like serine proteases, has been recently elucidated. Serine proteases have well characterized roles in diverse cellular activities, including blood coagulation, wound healing, digestion, and immune responses, as well as tumor invasion and metastasis. Importantly, because of the secreted nature of some of these enzymes, prostate- specific antigen (PSA) and kallikrein 2 have already found important clinical application as prostate cancer biomarkers. Of interest, kallikrein 10, kallikrein 6 (also known as zyme/ protease M/neurosiri), and matriptase (TADG-J 5/ MT-SPl) were all found highly expressed in ovarian serous papillary carcinomas compared to normal ovarian epithelial cells. These data confirm previous results showing high expression of several kallikrein genes and proteins in ovarian neoplasms. Moreover, these results obtained by high-throughput technologies for assaying gene expression further emphasize the view that some members of the kallikrein family have the potential to become novel ovarian cancer markers for ovarian cancer early diagnosis as well as targets for novel therapies against recurrent/refractory ovarian disease. Other highly overexpressed genes in ovarian serous papillary carcinomas include , stratifin, desmoplakin, SJ00A2, cytokeratins 6 and 7, MUC-I, and MMPl 2.

Down-Regulated Genes The present invention also identified a large number of down-regulated (at least

5-fold) genes in ovarian serous papillary carcinomas such as transforming growth factor beta receptor HI, platelet-derived growth factor receptor alpha, SEMACAP3, ras homolog gene family member I (ARHI), thrombospondin 2 and disabled-2/differentially expressed in

ovarian carcinoma 2 (Dab2/DOC2) (Table 3). Some of these genes encode well-known tumor suppressor genes such as SEMACAP3, ARHI, and Dab2/DOC2, while others encode for proteins important for ovarian tissue homeostasis or that have been previously implicated in apoptosis, proliferation, adhesion or tissue maintenance. In conclusion, several ovarian serous papillary carcinomas restricted markers have been identified herein. Some of these genes have been previously reported to be highly expressed in ovarian cancer while others have not been previously linked with this disease. Identification of TROP-] /Ep-CAM as the second most highly overexpressed gene in ovarian serous papillary carcinomas suggests that a therapeutic strategy targeting TROP-1/Ep-CAM by monoclonal antibodies, an approach that has previously been shown to increase survival in patients harboring stage III colon cancer, may be also beneficial in patients harboring chemotherapy-resistant ovarian serous papillary carcinomas. Targeting clαudin 3 and clαudin 4 by local and/or systemic administration of Clostridium Perfringens enterotoxin may represent another novel therapeutic modalities in patients harboring ovarian serous papillary carcinomas refractory to standard treatment.

Thus, the present invention is drawn to a method of detecting ovarian serous papillary carcinoma. The method involves performing statistical analysis on the expression levels of a group of genes listed in Table 2. Examples of such genes include lαminin, tumor- αssociαted calcium signal transducer I (TROP-I /Ep-CAM), tumor-associated calcium signal transducer 2 (TROP-2), claudin 3, claudin 4, ladinin I, S100A2, SERPIN2 (PAI-2), CD24, lipocalin 2, osteopontin, kallikrein 6 (protease M), kallikrein 10, matriptase and stratifin. Over-expression of these genes would indicate that such individual has ovarian serous papillary carcinoma. In general, gene expression can be examined at the protein or RNA level. Preferably, the examined genes have at least a 5-fold over-expression compared to expression in normal individuals. In one embodiment, gene expression is examined by DNA microarray and the data are analyzed by the method of hierarchical cluster analysis. In another embodiment, gene expression is determined by flow cytometric analysis or immunohistochemical staining.

The present invention also provides a method of detecting ovarian serous papillary carcinoma based on down-regulation of a group of genes listed in Table 3. Examples of such genes include transforming growth factor beta receptor III, platelet- derived growth factor receptor alpha, SEMACAP3, ras homo log gene family, member I (ARHI), thrombospondin 2 and disabled-2/differentially expressed in ovarian carcinoma 2 (Dab2/DOC2). In general, gene expression can be examined at the protein or RNA level. Preferably, the examined genes have at least a 5-fold down-regulation compared to expression in normal individuals. In one embodiment, gene expression is examined by DNA microarray and the data are analyzed by the method of hierarchical cluster analysis. In another

embodiment, gene expression is determined by flow cytometric analysis or immunohistochemicai staining.

In another aspect of the present invention, there is provided a method of treating ovarian serous papillary carcinoma by inhibiting the expression and function of tumor-associated calcium signal transducer 1 (TROP-I /Ep-CAM) gene. In general, inhibition of gene expression can be obtained using anti -TROP-I /Ep-CAM antibody or anti- sense oligonucleotide according to protocols well known in the art. For example, monoclonal anti-TROP-1 /Ep-CAM (chimeric/humanized) antibody can be used in antibody-directed therapy that has improved survival of patients described previously (1). In another embodiment, there is provided a method of treating ovarian serous papillary carcinoma by delivering Clostridium perfringens enterotoxin (CPE) to ovarian tumor cells overexpressing claudin 3 or claudin 4 protein. Preferably, the enterotoxin is delivered by systemic administration, intraperitoneal administration or intratumoral injection. For the purpose of administration, the enterotoxin may be formulated with vehicles and adjuvants known in the art such as mannitol, 1,3-butanediol, water, Ringer's solution, an isotonic sodium chloride solution, or other suitable dispersing or wetting and suspending agents, including synthetic mono- or diglycerides, and fatty acids, including oleic acid, or Cremaphor.

In a related application, CPE can be used to treat a chemotherapy resistant ovarian tumor. The enterotoxin may be used in combination with other methods to treat ovarian serous papillary carcinoma such as chemotherapy, radiotherapy or surgery.

The following examples are given for the purpose of illustrating various embodiments of the invention and are not meant to limit the present invention in any fashion. One skilled in the art will appreciate readily that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those objects, ends and advantages inherent herein. Changes therein and other uses which are encompassed within the spirit of the invention as defined by the scope of the claims will occur to those skilled in the art

EXAMPLE 1 Establishment of Primary Ovarian Serous Papillary Carcinoma And Normal Ovarian Epithelial Cell Lines

A total of 15 primary cell lines (i.e., 10 ovarian serous papillary carcinomas cell lines and 5 normal ovarian epithelial cell lines) were established after sterile processing of the tumor samples from surgical biopsies as previously described for ovarian carcinoma specimens (2-4). UCI-IOl and UCI-107, two previously characterized ovarian serous papillary carcinomas cell lines (5-6) were also included in the analysis. Tumors were staged according to the F.I. G. O. operative staging system. Radical tumor debulking, including a total abdominal hysterectomy and omentectomy, was performed in all ovarian carcinoma patients

while normal ovarian tissue was obtained from consenting donors who undergo surgery for benign pathology scraping epithelial cells from the ovarian surface. No patient received chemotherapy before surgical therapy. The patient and donors characteristics are described in Table 1. Briefly, normal tissue was obtained by scraping epithelial cells from the ovarian surface and placing cells in RPMI 1640 medium (Sigma Chemical Co., St. Louis, MO) containing 10% fetal bovine serum (FBS, Invitrogen, Grand Island, NY), 200 U/ml penicillin, and 200 μg/ml streptomycin. The epithelial explants were then allowed to attach and proliferate. Once the epithelial cells reached confluency, explants were trypsinized and subcultured for 3 to 4 passages before being collected for RNA extraction.

Viable tumor tissue was mechanically minced in RPMI 1640 to portions no larger than 1-3 mm ³ and washed twice with RPMI 1640. The portions of minced tumor were then placed into 250 ml flasks containing 30 ml of RPMI 1640 enzyme solution containing 0.14% collagenase Type I (Sigma, St Louis, MO) and 0.01% DNAse (Sigma, 2000 KU/mg), and incubated on a magnetic stirring apparatus overnight at 4° C. Enzymatically dissociated tumor was then filtered through 150 mm nylon mesh to generate single cell suspension. The resultant cell suspension was then washed twice in RPMI 1640 plus 10% fetal bovine serum (FBS, Invitrogen, Grand Island, NY). Primary cell lines were maintained in RPMI 1640 supplemented with 10% FBS, 200 U/ml penicillin, and 200 μg/ml streptomycin at 37°C, 5% CO ₂ in 75-150 cm ² tissue culture flasks (Corning Inc., Corning, NY). Tumor cells were collected for RNA extraction at a confluence of 50% to 80% after a minimum of two to a maximum of twelve passages in vitro. The epithelial nature and the purity of ovarian serous papillary carcinomas and normal ovarian epithelial cells cultures were verified by immunohistochemical staining and flow cytometric analysis with antibodies against cytokeratin as previously described (2,4). Only primary cultures which had at least 90% viability and contained >99% epithelial cells were used for total RNA extraction.

TABLE 1 Characteristics of the Patients

Patient Age Race Grade Chemotherapy regimen ^Sta S ^e

OSPC 1 42 White G2/3 TAX+CARB IV A

OSPC 2 67 White G3 TAX+CARB IH B

OSPC 3 61 White G3 TAX+CARB IH C

OSPC 4 60 White G3 TAX+CARB m e

OSPC 5 59 Afro-American G2/3 TAX+CARB IH C

OSPC 6 72 White G3 TAX+CARB γV A

OSPC 7 63 White G3 TAX+CARB III C

OSPC 8 74 Afro-American G2/3 TAX+CARB me

OSPC 9 68 White G3 TAX+CARB III B

OSPC 10 77 White G2/3 TAX+CARB m e

OSPC, ovarian serous papillary carcinoma.

EXAMPLE 2

Microarray Hybridization And Statistical Analysis

RNA purification, cDNA synthesis, cRNA preparation, and hybridization to the Affymetrix Human U95Av2 GeneChip microarray were performed according to the manufacturer's protocols and as reported (7). All data used in the analyses were derived from Affymetrix 5.0 software. GeneChip 5.0 output files are given as a signal that represents the difference between the intensities of the sequence-specific perfect match probe set and the mismatch probe set, or as a detection of present, marginal, or absent signals as determined by the GeneChip 5.0 algorithm. Gene arrays were scaled to an average signal of 1500 and then analyzed independently. Signal calls were transformed by the log base 2 and each sample was normalized to give a mean of 0 and variance of 1.

Statistical analyses of the data were performed with the software packages SPSS 10.0 (SPSS, Chicago, IL) and the significance analysis of microarrays (SAM) method (8). Genes were selected for analysis based on detection and fold change. In each comparison, genes having "present" detection calls in more than half of the samples in the overexpressed gene group were retained for statistical analysis if they showed >2-foId change between groups. Retained genes were subjected to SAM to establish a false discovery rate (FDR), then further filtered via the Wilcoxon rank sum (WRS) test at alpha=0.05. The false

discovery rate (FDR) obtained from the initial SAM analysis was assumed to characterize genes found significant via WRS.

The hierarchical clustering of average-linkage method with the centered correlation metric was used (9). The dendrogram was constructed with a subset of genes from 12,533 probe sets present on the microarray, whose expression levels vary the most among the 11 samples, and thus most informative. For the hierarchical clustering shown in Figure 1 and Figure 2, only genes significantly expressed and whose average change in expression level was at least two-fold were chosen. The expression value of each selected gene was re- normalized to have a mean of zero.

EXAMPLE 3

Gene Expression Profiles Distinguish Ovarian Serous Papillary Carcinoma Cells from Normal Ovarian Epithelial Cells And Identify Differentially Expressed Genes

Flash frozen biopsies from ovarian tumor tissue are known to contain significant numbers of contaminant stromal cells as well as a variety of host derived immune cells (e.g., monocytes, dendritic cells, lymphocytes). In addition, because ovarian epithelial cells represent a small proportion of the total cells found in the normal ovary, it is difficult to collect primary material that is free of contaminating ovarian stromal cells in sufficient quantities to conduct comparative gene expression analyses. Ovarian epithelial cells, however, can be isolated and expanded in culture for about 15 passages (2) while the majority of primary ovarian carcinomas can be expanded in vitro for at least a few weeks. Thus, short term primary ovarian serous papillary carcinomas and normal ovarian epithelial cell cultures were used in the following studies.

Comprehensive gene expression profiles of 10 primary ovarian serous papillary carcinomas cell lines and 5 primary normal ovarian epithelial cell lines were generated using high-density oligonucleotide arrays with 12,533 probe sets, which in total interrogated some 10,000 genes. In addition, gene expression profiles derived from two established and previously characterized cell lines (UCI-101 and UCI-107) were also analyzed. By combining the detection levels of genes significantly expressed in primary and established ovarian serous papillary carcinomas cell lines, very little correlation between the two groups of cells was found. Indeed, as shown in Figure 1, UCI-101 and UCI-107 established cell lines grouped together in the dendrogram while all 10 primary ovarian serous papillary carcinomas cell lines clustered tightly together in the rightmost columns separately by the 5 normal ovarian epithelial cell line controls. Because of these results, gene expression profile analysis was focused on the two homogeneous groups of primary ovarian serous papillary carcinomas cells and normal ovarian epithelial cells.

Using the nonparametric WRS test (p < 0.05) that readily distinguished between the two groups of primary cultures, 1,546 genes were found to be differentially

expressed between ovarian serous papillary carcinomas cells and normal ovarian epithelial cells. There were 365 genes showing >5-fold change along with " present" detection calls in more than half the samples in the overexpressed group. Of these, 350 were found significant by SAM, with a median FDR of 0.35% and a 90 ^lh percentile FDR of 0.59%. Of the 365 aforementioned genes, 299 yielded p<D.Q5 via WRS, and 298 were among the genes found significant by SAM.

Figure 2 describes the cluster analysis performed on hybridization intensity values for 298 gene segments whose average change in expression level was at least five-fold and which were found significant with both WRS test and SAM analysis. All 10 ovarian serous papillary carcinomas were grouped together in the rightmost columns. Similarly, in the leftmost columns all 5 normal ovarian epithelial cell cultures were found to cluster tightly together. The tight clustering of ovarian serous papillary carcinomas from normal ovarian epithelial cells was "driven" by two distinct profiles of gene expression. The first was represented by a group of 129 genes that were highly expressed in ovarian serous papillary carcinomas and underexpressed in normal ovarian epithelial cells (Table 2). Many genes shown previously to be involved in ovarian carcinogenesis are present on these lists, while others are novel in ovarian carcinogeneis. Included in this group of genes are laminin, claudin 3 and claudin 4, tumor-associated calcium signal transducer 1 and 2 (TROP-I IEp-CAM; TROP-2), ladinin 1, S100A2, SERPIN2 (PAJ-2), CD24, lipocalin 2, osteopontin, kallikrein 6 (protease M), kallikrein 10, matriptase (TADG-J 5) and stratifln (Table 2). Importantly, TROP- 1 IEp-CAM gene, which encodes for a transmembrane glycoprotein previously found to be overexpressed in various carcinoma types including colorectal and breast and where antibody-directed therapy has resulted in improved survival of patients, was 39-fold differentially expressed in ovarian serous papillary carcinomas when compared to normal ovarian epithelial cells (Table 2).

The second profile was represented by 170 genes that were highly expressed in normal ovarian epithelial cells and underexpressed in ovarian serous papillary carcinomas (Table 3). Included in this group of genes are transforming growth factor beta receptor III, platelet-derived growth factor receptor alpha, SEMACAP3, ras homolog gene family, member I (ARHI), thrombospondin 2 and disabled-2 '/ 'differentially expressed in ovarian carcinoma 2 (Dab2IDOC2) (Table 3).

TABLE 2

Upregulated Genes Expressed At Least 5 Fold Higher In Ovarian Serous Papillary Carcinoma

Compared With Normal Ovarian Epithelial Cells

Probe Set Gene Symbol Score(d)(SAM) p of WRS Ratio OVA/NOVA

35280_at LAMC2 1.68927386 0.006 46.45

35276_at CLDN4 1.734410451 0.015 43.76

33904_at CLDN3 1.650076713 0.02 40.24

575_s_at TACSTDl 1.705816336 0.02 39.36

32154_at TFA P2 A 1.667038647 0.002 33.31

39015_f_at KRT6E 1.0626291 17 0.047 28.02

1713_s_at CDKN2A 1.137682905 0.015 26.96

41376_i_at UGT2B7 0.939735032 0.047 24.81

3855 l_at LlCAM 1:151935363 0.008 24.66

291_s_at TACSTD2 1.249487388 0.047 24.46

33282_at LADl 1.422481563 0.006 24.31

34213_at KIBRA 1.533570321 0.002 23.06

38489_at HBP17 1.522882814 0.004 22.54

36869_at PAX8 1.43906836 0.004 22.20

38482_at CLDN7 1.307716566 0.027 20.01

37909_at LAMA3 1.121654521 0.027 19.24

34674_at SlOOAl 1.219106334 0.008 19.01

1620_at CDH6 0.908193479 0.036 18.69

3282 l_at LCN 2 1.99990601 0.008 18.13

522_s_at FOLR3 1.1 13781518 0.02 17.90

39660_at DEFBl 0.837612681 0.036 17.34

201 l_s_at BIK 1.594057668 0.006 17.23

41587_g_at FGFl 8 0.965726983 0.02 17.10

36929_at LAMB3 1.1 15590892 0.047 16.76

35726_at S100A2 1.036576352 0.004 15.05

1887_g_at WNT7A 1.186990893 0.004 14.75

35879_at GAL 1.223278825 0.002 14.65

266_s_at CD24 1.756569076 0.004 14.45

1 108_s_at EPHAl 1.242309171 0.006 14.36

37483 at HDAC9 1.406744957 0.006 14.28

Probe Set Gene Symbol Score(d)(SAM) p of WRS Ratio OVA/NOVA

31887_at — 1.311220827 0.011 13.68

1788_s_at DUSP4 1.22421987 0.003 13.65

32787_at ERBB3 0:996784565 ¹ 0.02 13.21

41660_at CELSRl 1.634286803 0.004 13.1 1

33483_at NMU 1.100849065 0.004 13.04

31792_at ANXA3 0.896090153 0.011 12.90

36838_at KLKlO 1.026306829 0.02 12.71

1585_at ERBB3 1.102058608 0.011 12.51

1898_at TRIM29 1.071987353 0.002 12.44

37185_at SERPINB2 0.815945986 0.027 12.26

406_at ITG B4 1.296194559 0.006 11.66

1914_at CCNAl 0.936342778 .0.011 11.21

977_s_at CDHl 0.93637461 0.036 11.19

37603_at ILlRN 1.103624942 0.015 11.14

35977_at DKKl 1.123240701 0.006 10.74

36133_at DSP 1.280269127 0.002 10.69

36113_s_at TNNTl 1.269558595 0.002 10.19

1802_s_at ERBB2 0.787465706 0.006 9.61

2092_s_at SPPl 1.34315986 0.02 9.53

35699_at BUBlB 1.026388835 0.006 9.49

37554_at KLK6 0.895036336 0.027 9.45

38515_at BMP7 0.945367 0.027 9.32

34775_at TSPAN-I 1.001195829 0.02 9.01

37558_at IMP-3 1.023799379 0.011 8.99

38324_at LISCH7 1.308000521 0.006 8.96

39610_at HOXB2 1.355268631 0.006 8.64

572_at TTK 1.122796615 0.006 8.53

1970_s_at FGFR2 1.022708001 0.02 8.30

160025_at TGFA 1.065272755 0.015 8.28

41812_s_at NUP210 1.39287031 0.006 8.26

34282_at NFE2L3 1.165273649 0.008 8.06

2017_s_at CCNDl 1.114984456 0.002 8.04

33323 r at SFN 1.202433185 0.008 8.01

Probe Set Gene Symbol Score(d)(SAM) p of WRS Ratio OVA/NOVA

38766_at SRCAP 1.131917941 0.008 7.99

41060_at CCNEl 1,151246634 0.006 7.97

39O16_r_at KRT6E 0.973486831 0.008 7.91

31610_at MAP17 1.0156502 0.027 7.81

2027_at S100A2 0.941919001 0.008 7.76

4l8_at MKI67 0.826426448 0.011 7.46

I536_at CDC6 1.08868941 0.017 7.37

634_at PRSS8 0.899891713 0.02 7.30

34342_s_at SPPl 1.318723271 0.02 7.27

182_at ITPR3 li 107167336 0.006 7.27^

32382_at UPKlB 0.731294678 0.047 7.16

863_g_at SERPINB5 0.783530451 0.015 7.14

9O4_s_at TOP2A 0.971648429 0.02 7.12

40095_at CA2 0.798857154 0.027 7.02

41294_at KRT7 1:082553892 0.01 1 7.00

3995 l_at PLSl 0.995091449 0.006 6.94

3805 l_at MAL 0!819842532 0.036 6.82

40726_at KIFI l 0.803689697 0.036 6.78

1 148_s_at — 01683569558 0.047 6.72

37920_at PITXl 0.996497645 0.015 6.67

371 17_at ARHGAP8 1.129131077 0.002 6.65

38881_i_at TRIM 16 0:721698355 0.047 6.59

3425 l_at HOXB5 1.219463307 0.002 6.52

41359_at PKP3 1.047269618 0.004 6.50

40145_at TOP2A 0^961173129 0.02 6.48

37534_at CXADR 0.888147605 0.006 6.32

4O3O3_at TFAP2C 0:948734146 0.004 6.30

31805_at FGFR3 0.969764101 0.01 1 6.28

33245_at MAPK 13 0.877514586 0.01 1 6.27

885__g_at ITGA3 0.702747685 0.036 6.19

34693_at STHM 0.872525584 0.008 6.15

38555_at DUSPlO 0:880305317 0.008 6.12

38418 at CCNDl 1.071102249 0.002 5.97

Probe Set Gene Symbol Score(d)(SAM) p of WRS Ratio OVA/NOVA

3373O_at RAI3 0.813298748 0.011 5.90

39109_at TPX2 1.040973216 0.01 1 5.87

36658_at DHCR24 1.122129795 0.004 5.81

3528 l_at LAMC2 0.747766326 0.047 5.78

38749_at MGC29643 0.683275086 0.036 5.77

1083_s_at MUCl 0.746980491 0.027 5.75

40079_at RAI3 0.709840659 0.02 5.73

2047_s_at JUP 0.815282235 0.011 5.62

32275_at SLPI 0.940625784 0.02 5.61

2020_at CCNDl 0.926408163 0.002 5.51

33324_s_at CDC2 1.026683994 0.008 5.47

36863_at HMMR 0.96343264 0.006 5.46

1657_at PTPRR 0.764510362 0.02 5.41

37985_at LMNBl 0.895475347 0.008 5.36

36497_at C14orf78 0.942921564 0.008 5.33

2021_s_at CCNEl 0.893228297 0.006 5.33

3789O_at CD47 0.775908217 0.015 5.33

40799_at C16orf34 0.852774782 0.008 5.30

35309_at ST 14 0.852534105 0.008 5.30

1599_at CDKN3 0.925527261 0.02 5.29

981_at MCM4 1.058558782 0.006 5.28

32715_at VAMP8 0.938171642 0.006 5.28

3863 l_at TNFAIP2 0.72369235 0.015 5.26

34715_at FOXMl 1.31035831 0.008 5.24

33448_at SPINTl 0.924028022 0.015 5.21

419_at MKI67 0.938133197 0.015 5.16

1651_at UBE2C 1.436239741 0.008 5.14

35769_at GPR56 0.937347548 0.015 5.08

3731O_at PLAU 0.885110741 0.036 5.08

3676 l_at ZNF339 0.937123503 0.011 5.05

37343_at ITPR3 1.001079303 0.003 5.05

40425_at EFNAl 0.813414458 0.047 5.04

1803_at CDC2 0.732852195 0.027 5.00

TABLE 3

Upregulated Genes Expressed At Least 5 Fold Higher In Normal Ovarian Epithelial Cells Compared With Ovarian Serous Papillary Carcinoma

Ratio

Probe Set Gene Symbol Score(d)(SAM) p of WRS NOVA/OVA

3970 l_at PEG3 1.991111245 0.006 1 13.32

32582_at MYHI l 1.921434447 0.002 67.31

39673_i_at ECM2 1.740409609 0.011 53.54

37394_at C7 1.597329897 0.02 50.45

37247_at TCF21 2.261979734 0.002 39.29

1897_at TGFBR3 1.648143277 0.003 38.12

36627_at SPARCLl 1.610346382 0.008 37.84

37015_at ALDHlAl 1.886579474 0.002 35.18

38469_at TM4SF3 1.620821878 0.003 34.43

35717_at AJBCA8 1.709820793 0.008 33.92

32664_at RNASE4 1.720857082 0.003 32.94

40775_at 1TM2A 1.393751 125 0.006 31.35

38519_at NR1H4 1.431579641 0.004 27.02

37017_at PLA2G2A 1.263990266 0.01 1 26.68

3668 l_at APOD 1.44030134 0.008 26.04

34193_at CHLl 1.738491852 0.006 25.97

34363_at SEPPl 1.490374268 0.015 25.93

1501_at IGFl 1.1 16943817 0.027 25.87

33240_at SEMACAP3 1.818843975 0.003 25.54

36939_at GPM6A 0.924236354 0.047 25.47

614_at PLA2G2A 1.391395227 0.003 23.15

37407_s_at MYHI l 1.72766007 0.002 22.73

39325_at EBAF 1.248164036 0.02 22.49

767_at — 1.688001805 0.002 21.90

37595_at — 1.582101386 0.004 20.94

1290_g_at GSTM5 1.383630361 0.003 20.84

34388_at COL14A1 1.400078214 0.015 20.39

607 s at VWF 1.314435559 0.002 19.05

Ratio

Probe Set Gene Symbol Score(d)(SAM) p of WRS NOVA/OVA

37599_at AOXl 1.669903577 0.003 17.61

41504_s_at MAF 1.463988429 0.008 16.40

41412_at PIPPIN 1.799353403 0.002 16.08

279_at NR4A1 1.194733065 0.008 15.42

38427_at COL15A1 1.570514035 0.002 15.38

41405_at SFRP4 1.478603828 0.002 14.44

39066_at MFAP4 1.91469237 0.004 14.26

1731_at PDGFRA 1.791307012 0.003 13.91

36595_s_at GATM 1.382271028 0.004 13.86

34343_at STAR 2.080476608 0.003 13.67

36917_at LAMA2 1.359731285 0.006 13.51

38430_at FABP4 1.054221974 0.02 13.05

36596_r_at GATM 1.22177547 0.008 12.67

35898_at WISP2 1.276226302 0.004 12.55

36606_at CPE 1.608244463 0.003 12.30

32057_at LRRC 17 1.345223643 0.011 12.22

3343 l_at FMOD 1.516795166 0.003 12.17

34985_at CILP 0.905018335 0.02 1 1.53

755_at ITPRl 1.433938835 0.002 11.06

1466_s_at FG F7 1.184028604 0.027 1 1.00

36727_at — 0.98132702 0.036 10.96

1 103_at RNASE4 1.456068199 0.002 10.88

32666_at CXCL12 1.342426238 0.006 10.72

914_g_at ERG 1.264721284 0.002 10.54

40698_at CLECSF2 1.325237675 0.002 10.46

36873_at VLDLR 1.344197327 0.004 10.45

1090_f_at — 0.914708216 0.027 10.34

36042_at NTRK2 0.950553444 0.02 10.32

3631 1_at PDElA 1.356950738 0.004 10.21

41685_at NY-REN-7 0.8848466 0.036 10.08

32847_at MYLK 1.545610138 0.002 10.00

35358_at TENCl 1.539140855 0.003 9.97

32249 at HFLl 1.257702238 0.02 9.86

Ratio

Probe Set Gene Symbol Score(d)(SAM) p of WRS NOVA/OVA

36695_at na 1.452847153 0.003 9.82

1987_at PDGFRA 1.50655467 0.002 9.76

37446_at GASP 1.219014593 0.004 9.76

35752_s_at PROSl 1.211272096 0.008 9.66

36533_at PTGIS 1.882348646 0.004 9.62

38886_i__at ARHI 1.127672988 0.02 9.59

36733_at FLJ32389 1.420588897 0.011 9.57

DKFZP586A052

38717_at 2 1.158933663 0.015 9.50

3255 l_at EFEMPl 1.385495033 0.004 9.38

1968_g_at PDGFRA 1.364848071 0.003 9.31

33910_at PTPRD 1.129963902 0.008 9.20

32778_at ITPRl 1.370809534 0.002 9.08

280_g_at NR4A1 1.074894321 0.006 8.79

35389_s_at ABCA6 1.209294071 0.01 1 8.79

32889_at RPIB9 1.145333813 0.003 8.74

37248_at CPZ 1.238797022 0.002 8.69

39674_r_at ECM2 0.874009817 0.027 8.67

3391 l_at PTPRD 1.099609918 0.02 8.66

35234_at RECK 1.407865518 0.008 8.58

32119_at — 1.153957574 0.011 8.57

35998_at LOC284244 1.104281231 0.008 8.54

37279_at GEM 1.012760866 0.008 8.31

35702_at HSDI lBl 1.164189513 0.004 8.28

32126_at FGF7 1.336918337 0.008 8.22

36867_at — 1.273166453 0.008 8.21

38653_at PMP22 1.422063697 0.002 8.19

38875_r_at GREBl 1.026886865 0.015 8.10

35366_at NID 1.483421362 0.002 8.10

34417_at FLJ36166 0.783978445 0.047 7.98

3722 l_at PRKAR2B 0.927090765 0.036 7.91

3903 l_at COX7A1 1.564725491 0.004 7.89

39757 at SDC2 1.288106392 0.002 7.80

Ratio

Probe Set Gene Symbol Score(d)(SAM) p of WRS NOVA/OVA

36629_at DSIPI 0.981563882 0.008 7.79

35390_at ABCA6 1.026714913 0.036 7.79

39629_at PLA2G5 1.405181995 0.002 7.70

4096 l_at SMARCA2 0.996692724 0.015 7.68

719_g_at PRSS I l 1.399043078 0.002 7.65

40856_at SERPINFl 1.077533093 0.008 7.55

37008_r_at SERPINA3 1.134224016 0.002 7.53

33834_at CXCL12 1.060878451 0.002 7.51

31880_at D8S2298E 1.177864913 0.002 7.45

37628_at MAOB 1.194963489 0.004 7.43

34853_at FLRT2 1.250330254 0.027 7.41

38887_r_at ARHI 1.169953614 0.015 7.32

38220_at DPYD 1.024334451 0.02 7.26

1327_s_at MAP3K5 0.891703475 0.02 7.23

138O_at FG F7 1.096254206 0.004 7.14

37573_at ANGPTL2 1.052539345 0.002 7.08

718_at PRSS 11 1.381205346 0.002 6.99

36712_at — 1.15195149 0.005 6.88

1709_g_at MAPKlO 1.160327795 0.002 6.85

39123_s_at TRPCl 1.060327922 0.015 6.79

38627_at HLF 0.911787462 0.036 6.79

32076_at DSCRlLl 1.127515982 0.002 6.77

36669_at FOSB 1.023057503 0.011 6.65

38194_s_at IGKC 1.239936045 0.015 6.64

39545_at CDKNlC 1.040717569 0.004 6.62

36993_at PDGFRB 1.384657766 0.004 6.60

35837_at SCRGl 1.023840456 0.036 6.48

1507_s_at EDNRA 1.23933124 0.004 6.48

40488_at DMD 1.291791538 0.002 6.42

38364_at 1.030881 108 0.004 6.35

41424_at PON3 0.946224951 0.036 6.32

32109_at FXYDl 1.005577422 0.004 6.19

1 182 at PLCLl 1.097390316 0.002 6.17

Ratio

Probe Set Gene Symbol Score(d)(SAM) p of WRS NOVA/OVA

31897_at DOCl 1.533672652 0.003 6.13

37208_at PSPHL 1.007759699 0.015 6.08

36396_at — 1.009684807 0.015 6.07

41505_r_at MAF 1.1 16101319 0.006 6.06

37765_at LMODl 1.127716375 0.003 6.00

37398_at PECAMl 0.970664041 0.008 5.98

41013_at FLJ31737 1.036561659 0.003 5.98

39279_at BMP6 1.106724571 0.002 5.93

1527_s_at CGOl 8 0.804755548 0.047 5.91

39038_at FBLN5 1.279283798 0.004 5.89

32542_at FHLl 1.134214637 0.002 5.88

38508_s_at TNXB 0.878513741 0.011 5.74

32696_at PBX3 0.888011703 0.027 5.69

41796_at PLCL2 0.857601993 0.02 5.68

34473_at TLR5 0.871815246 0.027 5.67

661_at GAS l 1.267909476 0.004 5.66

41449_at SGCE 1.050056933 0.004 5.65

35740_at EMILIN l 1.366368794 0.01 1 5.58

37908_at GNG I l 0.989043327 0.004 5.43

37406_at MAPRE2 1.265872665 0.002 5.41

33802_at HMOXl 1.034088234 0.015 5.41

39106_at APOAl 1.266005754 0.008 5.40

1771_s_at PDGFRB 1.336082701 0.006 5.39

39409_at ClR 1.05784087 0.01 1 5.39

32535_at FBN l 1.422415283 0.006 5.35

37710_at MEF2C 0.98149558 0.011 5.35

37958_at TM4SF10 1.293658009 0.003 5.35

33756_at A0C3 0.829203515 0.02 5.29

36569_at TNA 0.926096917 0.006 5.25

3977 l_at RHOBTB l 1.048906896 0.008 5.20

39852_at SPG20 0.82401517 0.027 5.20

35168_f_at COL 16Al 1.509830282 0.011 5.18

33244 at CHN2 0.92878389 0.015 5.18

Ratio

Probe Set Gene Symbol Score(d)(SAM) p of WRS NOVA/OVA

35681_r_at ZFHXlB 1.170745794 0.006 5.14

2087_s_at CDHI l 1.656534188 0.008 5.12

40496_at CIS 0.973175912 0.01 1 5.10

41 137_at PPP1R12B 1.12885067 0.008 5.07

39698_at HOP 0.797252583 0.01 1 5.05

3821 l_at ZNF288 0.926263264 0.015 5.04

41839_at GASl 1.127093791 0.006 5.03

39979_at FlO 0.890787173 0.002 5.02

1135_at GPRK5 1.150554994 0.002 5.01

479 at DAB2 1.255638531 0.006 5.01

EXAMPLE 4

Validation of the Microarray Data By Quantitative Real-Time PCR

Quantitative real time PCR assays were used to validate the microarray data. Four highly differentially expressed genes between normal ovarian epithelial cells and ovarian serous papillary carcinoma (i.e., TROP l, CD24, Claudin-3 and Claudin-4) were selected for the analysis.

Quantitative real time PCR was performed with an ABI Prism 7000 Sequence Analyzer using the manufacturer's recommended protocol (Applied Biosystems, Foster City, CA). Each reaction was run in triplicate. The comparative threshold cycle (C ₁ .) method was used for the calculation of amplification fold as specified by the manufacturer. Briefly, five mg of total RNA from each sample was reverse transcribed using Superscript Il Rnase H Reverse Transcriptase (Invitrogen, Carlsbad, CA). Ten ml of reverse transcribed RNA samples (from 500 ml of total volume) were amplified by using the TaqMan Universal PCR Master Mix (Applied Biosystems) to produce PCR products specific for TROP l, CD24, Claudin-3 and Claudin-4. Primers specific for 18s ribosomal RNA and empirically determined ratios of 18s competimers (Applied Biosystems) were used to control for the amounts of cDNA generated from each sample.

Primers for TROP l, claudin-3 and claudin-4 were obtained from Applied Biosystems as assay on demand products. Assays ID were HsOO15898O_ml (TROP-I), Hs00265816_sl (claudin-3), and HsOO533616_sl (claudin-4). CD24 primers sequences were as following: forward, S'-CCCAGGTGTTACTGTAATTCCTCAA (SEQ ID NO.1); reverse, S'-GAACAGCAATAGCTCAACAATGTAAAC (SEQ ID NO.2). Amplification was carried out by using 1 unit of polymerase in a final volume of 20 μl containing 2.5 mM

MgCI ₂ . TaqGold was activated by incubation at 96°C for 12 min, and the reactions were cycled 26-30 times at 95 ⁰ C for 1 min, 55°C for 1 min, and 72°C for 1 min, followed by a final extension at 72°Cfor 10 min. PCR products were visualized on 2% agarose gels stained with ethidium bromide, and images were captured by an Ultraviolet Products Image Analysis System. Differences among ovarian serous papillary carcinoma and normal ovarian epithelial cells in the quantitative real time PCR expression data were tested using the Kruskal-Wallis nonparametric test. Pearson product-moment correlations were used to estimate the degree of association between the microarray and quantitative real time PCR data.

A comparison of the microarray and quantitative real time PCR data for these genes is shown in Figure 3. Expression differences between ovarian serous papillary carcinoma and normal ovarian epithelial cells for TROP-J , (p = 0.02), CD24 (p = 0.004), claudin-3 (p = 0.02), and claudin-4 (p — 0.01) were readily apparent (Table 2 and Figure 3). Moreover, for all four genes tested, the quantitative real time PCR data were highly correlated to the microarray data (p < 0.001) (r = 0.81, 0.90, 0.80 and 0.85, respectively). Thus, quantitative real time PCR data suggest that most array probe sets are likely to accurately measure die levels of the intended transcript within a complex mixture of transcripts.

EXAMPLE 5

Flow Cytometry Analysis of TROP-I And CD24 Expression An important issue is whether differences in gene expression result in meaningful differences in protein expression. Because TROP-I IEp-CAM gene encodes the target for the anti-Ep-CAM antibody 17- IA, (Edrecolomab (Panorex), that has previously been shown to increase survival in patients harboring stage III colon cancer, expression of Ep-CAM protein by FACS analysis was analyzed on 13 primary cell lines , i.e., 10 ovarian serous papillary carcinoma cell lines and 3 normal ovarian epithelial cell lines. As positive controls, breast cancer cell lines (B7-474 and SK-BR-3, American Type Culture Collection) known to overexpress TROP-I I Ep-CAM were also studied.

Unconjugated anti-TROP-1/EP-CAM (IgG2a), anti-CD24 (IgG2a) and isotype control antibodies (mouse IgG2a) were all obtained from BD PharMingen (San Diego, CA). Goat anti-murine FITC labeled mouse Ig was purchased from Becton Dickinson

(San Jose, CA). Flow cytometry was conducted with a FACScan, utilizing cell Quest software

(Becton Dickinson).

High TROP- 1/Ep-CAM expression was found on all ten primary ovarian serous papillary carcinoma cell lines tested (100% positive) with mean fluorescence intensity (MFI) ranging from 1 16 to 280 (Figure 4). In contrast, primary normal ovarian epithelial cell lines were negative for TROP-1/Ep-CAM surface expression (p < 0.001) (Figure 4).

Similarly, CD24 expression was found on all primary ovarian serous papillary carcinoma cell lines tested (100% positive) with mean fluorescence intensity (MFI) ranging from 26 to 55

(Figure 4). In contrast, primary normal ovarian epithelial cell lines were negative for CD24 surface expression (p < 0.005) (Figure 4). These results show that high expression of the TROP-J /Ep-CAM and CD24 genes by ovarian serous papillary carcinoma correlate tightly with high protein expression by the tumor cells. Breast cancer positive controls were found to express high levels of TROP- 1/Ep-CAM (data not shown).

EXAMPLE 6

Immunohistochemical Analysis of TRQP-I And CD24 Expression

To determine whether the high or low gene expression and Ep-CAM and CD24 protein expression detected by microarray and flow cytometry are the result of a selection of a subpopulation of cancer cells present in the original tumor, or whether in vitro expansion conditions may have modified gene expression, immunohistochemical analysis of T ROP-I /Ep-CA M and CD24 protein expression was performed on formalin-fixed tumor tissue from all uncultured primary surgical specimens. Study blocks were selected after histopathologic review by a surgical pathologist The most representative hematoxylin and eosin-staiπed block sections were used for each specimen. Briefly, immunohistochemical stains were performed on 4 mm-thick sections of formalin-fixed, paraffin-embedded tissue. After pretreatment with 10 itiM citrate buffer at pH 6.0 using a steamer, they were incubated with anti-Ep-CAM mAb (PharMingen) or anti-CD24 antibody (Neo Markers, Fremont, CA) at 1:2000 dilution. Slides were subsequently labelled with streptavidin-biotin (DAKO, Glostrup, Denmark), stained with diaminobenzidine and counterstained with hematoxylin. The intensity of staining was graded as 0 (staining not greater than negative control), 1+ (light staining), 2+ (moderate staining), or 3+ (heavy staining).

As shown in the left panel of Figure 5, heavy apical membranous staining for CD24 protein expression was noted in all ovarian serous papillary carcinoma specimens that also overexpressed the CD24 gene and its gene product as determined by microarray and flow cytometry, respectively. In contrast, negative or low (i.e., score 0 or 1+) staining was found in all normal ovarian epithelial cell samples tested by immunohistochemistry. Similarly, as shown in the right panel of Figure 5, heavy membranous staining for TROP-1/Ep-CAM protein expression (i.e., score 3+) was noted in all ovarian serous papillary carcinoma specimens that also overexpressed the TROP- 1 IEp-C 'AM gene and its gene product as determined by microarray and flow cytometry, respectively. In contrast, negative or low (i.e., score 0 or 1+) staining was found in all normal ovarian epithelial cell samples tested by immunohistochemistry.

EXAMPLE 7 Primary and established human ovarian cancer cell lines

Fresh human ovarian cancer cell lines, i.e., 11 chemotherapy-naive tumors

generated from samples obtained at the time of primary surgery and six chemotherapy- resistant tumors obtained from samples collected at the time of tumor recurrence, and five established ovarian cancer cell lines (UCI 101, UCI 107, CaOV3, OVACAR-3, and OVARK- 5) were evaluated for claudin-3 and claudin-4 expression by real-time PCR. Three of the six ovarian tumor specimens found resistant to chemotherapy in vivo including OVA-I, a fresh ovarian serous papillary carcinoma (OSPC) used to establish ovarian xenografts in SCID mice (i.e., severely immunocompromised animals), were confirmed to be highly resistant to multiple chemotherapeutic agents when measured as percentage cell inhibition by in vitro extreme drug resistance assay (Oncotech, Inc., Irvine, CA). UCI-101 and UCI-107, two previously characterized and established human serous ovarian cancer cell lines and CaOV3 and OVACAR-3 (American Type Culture Collection Manassas, VA), and OVARK-5 established from a stage IV ovarian cancer patient were also used in the following experiments. Other control cell lines evaluated in the CPE assays included Vero cells, normal ovarian epithelium (NOVA), normal endometrial epithelium, normal cervical keratinocytes, primary squamous and adenocarcinoma cervical cancer cell lines, Epstein-Barr transformed B lymphocytes, and human fibroblasts. With the exception of normal cervical keratinocytes and cervical cancer cell lines that were cultured in serum-free keratinocyte medium, supplemented with 5 ng/mL epidermal growth factor and 35 to 50 mg/mL bovine pituitary extract (Invitrogen, Grand Island, NY) at 37 ° C, 5% CO2, all other fresh specimens were cultured in RPMI 1640 (Invitrogen) containing 10% fetal bovine serum (FBS; Gemini Bio-products, Calabasas, CA), 200 units/mL penicillin, and 200 mg/mL streptomycin.

EXAMPLE 8

RNA extraction and quantitative real-time PCR RNA isolation from primary and established cell lines was done using TRIzoI

Reagent (Invitrogen) according to the manufacturer's instructions. Quantitative PCR was done with an ABI Prism 7000 Sequence Analyzer using the manufacturer's recommended protocol (Applied Biosystems, Foster City, CA) to evaluate expression of claudin-3 and cIaudin-4 in all the samples. Each reaction was run in triplicate. Briefly, 5 mg total RNA from each sample were reverse transcribed using Superscript III first-strand cDNA synthesis (Invitrogen, Carlsbad, CA). Five microliters of reverse transcribed RNA samples (from 500 mL of total volume) were amplified by using the TaqMan Universal PCR Master Mix (Applied Biosystems) to produce PCR products specific for claudin-3 and claudin-4. The primers for claudin-3 and claudin-4 were obtained from Applied Biosystems as Assay-on-Demand products. Assay IDs were Hs00265816_sl (claudin-3) and Hs00433616_sl (claudin-4). The comparative threshold cycle (C ₁ .) method (PE Applied Biosystems) was used to determine gene expression in each sample relative to the value observed in the nonmalignant ovarian epithelial cells, using glyceraldehyde-3-phosphate dehydrogenase (Assay-on-Demand Hs999-

999O5_ml) RNA as internal controls.

Both claudin-3 and/or cIaudin-4 genes were highly expressed in all primary ovarian cancers studied when compared with normal ovarian epithelial cells as well as other normal cells or other gynecologic tumors (Figure 6A-B). Established ovarian cancer cell lines (UCI 101 , UCI 107, CaOV3, OV ACAR-3, and OVARK-5) were found to express much lower levels of claudin-3 and/or claudin-4 compared with primary ovarian tumors (Figure 6A-B). Finally, claudin-3 and/or claudin-4 expression was extremely low in all control tissues examined, including normal ovarian epithelium, normal endometrial epithelium, normal cervical keratinocytes, and normal human fibroblasts (Figure 6A-B). When OSPC collected at the time of primary debulking surgery (six cases) were compared for claudin-3 and/or claudin-4 receptor expression to those collected at the time of tumor recurrence after multiple courses of chemotherapy (six cases), chemotherapy resistant tumors were found to express significantly higher levels of claudin-3 and/or claudin-4 receptors (P<0.05; Figure 7A-D). When three primary ovarian cancers naive to chemotherapy were compared with recurrent ovarian cancers recovered from the same patients following chemotherapy (i.e., matched autologous tumor samples), chemotherapy-resistant tumors were again found to express higher levels of claudin-

3 and claudin-4 (Figure 7A-D).

EXAMPLE 9 Claudin-4 immunostaining of formalin-fixed tumor tissues

Ovarian tumors were evaluated by standard immunohistochemical staining on formalin-fixed tumor tissue for claudin-4 surface expression. Study blocks were selected after histopathologic review by a surgical pathologist. The most representative H&E-stained block sections were used for each specimen. Briefly, immunohistochemical stains were done on 4- mm-thick sections of formalin-fixed, paraffin-embedded tissue. After pretreatment with 10 mmol/L citrate buffer (pH 6.0) using a steamer, they were incubated with mouse anti-claudin-

4 antibodies (Zymed Laboratories, Inc., San Francisco, CA). Antigen-bound primary antibody was detected using standard avidin-biotin immunoperoxidase complex (DAKO Corp., Carpinteria, CA). Cases with <10% staining in tumor cells were considered negative for claudin expression. The positive cases were classified as follows regarding the intensity of claudin-4 protein expression: +, weak staining; ++, medium staining; and +++, intense staining. Subcellular localization (membrane or cytoplasm) was also noted. Negative controls, in which the primary antibodies were not added, were processed in parallel.

As shown in Figure 8A, moderate to heavy membranous staining for claudin^φ protein expression was noted in all the cancer specimens that overexpressed the claudin-4 transcript. In contrast, negative or low staining was found in all the normal ovarian epithelium tested by immunohistochemistry (Figure 8B).

EXAMPLE 10

Cloning and purification of NH2-ternrtinus His-tagged Clostridium perfringens enterotoxin

C. perfringens strain 12917 obtained from American Type Culture Collection (Manassas, VA) was grown from a single colony and used to prepare bacterial DNA with the InstaGene kit according to manufacturer's directions (Bio-Rad Laboratories, Hercules, CA). The bacterial DNA fragment encoding full-length CPE gene (Genbank M98037) was PCR amplified (primer 1, 5V-CGC CAT ATG ATG CTT AGT AAC AAT TTA AAT-3V, SEQ ID NO: 3; primer 2, 5V-GAT GGA TCC TTA AAA TTT TTG AAA TAA TAT TG-3V, SEQ ID NO: 4). The PCR products were digested with the restriction enzymes Ndel/BamHI and cloned into a Ndel/BamHI-digested pET _r 16b expression vector (Novagen, Madison, WI) to generate an in-frame NH2-terminus His-tagged CPE expression plasmid, pET-16b-10xHIS- CPE. Histagged CPE toxin was prepared from pET-16b- 1 OxHIS-CPE transformed Escherichia coli M 15. Transformed bacteria were grown at 37 ⁰ C to 0.3 to 0.4 absorbance at 600 nm, after which CPE protein expression was induced overnight with 1 mmol/L isopropyl b-D-thio-galactoside, and the cells harvested, resuspended in 150 mmol/L NaH2PO4, 25 mmol/L Tris-HCL, and 8 mol/L urea (pH 8.0) buffer, and lysed by centrifugation at 10,000 rpm for 30 minutes. The fusion protein was isolated from the supernatant on a Poly-Prep Chromatography column (Bio-Rad). His-tagged CPE was washed with 300 mmol/L NaH ₂ PO4, 25 mmol/L Tris-HCI, and 10 mol/L urea (pH 6.0), and eluted from the column with 200 mmol/L NaH ₂ PO4, 25 mmol/L Tris-HCI, and 8 mol/L urea (pH 6.0). To reduce the level of endotoxin from His-tagged CPE protein, 10 washings with ice-cold PBS with Triton X-1 14 (from 1% to 0.1%) and 10 washings with ice-cold PBS alone were done. Dialysis (Mr 3,500 cutoff dialysis tubing) against PBS was done overnight. Purified CPE protein was then sterilized by 0.2 mm filtration and frozen in aliquots at —70 ⁰ C.

EXAMPLE 11 Clostridium perfringens enterotoxin treatment of cell lines and trypan blue exclusion test

Tumor samples and normal control cells were seeded at a concentration of I xIO ⁵ cells/well into six-well culture plates (Costar, Cambridge, MA) with the appropriate medium. Adherent tumor samples, fibroblasts, and normal epithelial control cell lines were grown to 80% confluence. After washing and renewal of the medium, CPE was added to final concentrations ranging from 0.03 to 3.3 mg/itiL After incubation for 60 minutes to 24 hours at 37 ⁰ C, 5% CO ₂ , floating cells were removed and stored, and attached cells were trypsinized and pooled with the floating cells. After staining with trypan blue, viability was determined by counting the number of trypan blue-positive cells and the total cell number.

As shown in Figure 9, regardless of their sensitivity or resistance to chemotherapy, all ovarian tumors tested were found sensitive to CPE-mediated cytolysis. The cytotoxic effect was dose dependent and was positively correlated to the levels of either

claudin-3 or claudin-4 expression as tested by RTPCR in tumor samples. Importantly, although ovarian tumors showed different sensitivities to CPE exposure, no ovarian cancer was found viable after 24 hours exposure to CPE at the concentration of 3.3 mg/mL. In contrast, all normal controls tested including ovarian epithelium, cervical keratinocytes, and mononuclear cells as well as cervical cancer cell lines lacking claudin-3 or claudin-4 were not affected by CPE (Figure 9).

EXAMPLE 12

SCID mouse tumor xenografts and Clostridium perfringens enterotoxin treatment C.B-17/SCID female mice 5 to 7 weeks old were obtained from Harlan Sprague-

Dawley (Indianapolis, IN). They were given commercial basal diet and water ad libitum. Animals were used to generate ovarian tumor xenografts. The OVA-I cancer cell line was injected i.p. at a dose of 5xlO ⁶ to 7.5xlO ⁶ into C.B-17/SCID mice in groups of five. In the first set of experiments (i.e., large ovarian tumor burden challenge), 4 weeks after i.p. tumor injection, mice were injected i.p. with 5.0, 5.5, and 6.5 mg CPE dissolved in 1 mL sterile saline at 72-hour intervals. In a second set of experiments, groups of five mice received 7.5 or 8.5 mg of CPE i.p. at 72-hour intervals 1 week after i.p. OVA-I tumor injection at a dose of 5xlO ⁶ tumor cells. All animals were observed twice daily and weighed weekly and survival was monitored. In addition, groups of mice injected i.p. at a dose of 5xlO ⁶ to 7.5xlO ⁶ OVA-I tumor cells were killed at 1, 2, 3, and 4 weeks for necropsy and pathologic analysis. The remaining animals were killed and examined just before they died of i.p. carcinomatosis and malignant ascites. Statistical differences in claudin-3 and claudin-4 expression between chemotherapy-naive and chemotherapy-recurrent/resistant ovarian tumors were tested using the Student's t test. For the OVA-I animal model, survivals were plotted using Kaplan-Meier methods and compared using the log-rank test. P < 0.05 was used for statistical significance.

CPE injections were well tolerated and no adverse events were observed throughout the complete treatment protocol either in control mice receiving CPE alone or CPE- treated mice harboring large tumor burden. Mice harboring OVA-I treated with saline all died within 6 weeks from tumor injection with a mean survival of 38 days (Figure 10A). In contrast, animals treated with multiple CPE injections survived significantly longer than control animals did (P < 0.0001 ; Figure 10A). The increase in survival in the different groups of mice treated with the diverse doses of CPE was clearly dose dependent, with the highest dose injected (i.e., 6.5 mg every 72 hours) found to provide the longer survival (Figure 10A). In another set of experiments, mice harboring OVA-I (a week after tumor injection with 5xlO ⁶ cells) were treated with i.p. CPE injections at a dose ranging from 7.5 to 8.5 mg every 72 hours. Whereas mice harboring OVA-I treated with saline all died within 9 weeks from tumor injection (Figure 10B), three of five (60%) and five of five (100%) of the mice treated with multiple i.p. injections of CPE remained alive and free of detectable tumor for the duration of the study

period (i.e., over 120 days, P < 0.0001).

Pharmacologic studies in ovarian cancer patients have shown a marked therapeutic advantage to the i.p. delivery of drugs and bioiogicals combined with a significant reduction in systemic toxicity resulting from i.p. drug administration when compared with an identical dose of the drug given i.v.. These clinical observations, combined with the fact that ovarian cancer remains confined to the peritoneal cavity for much of its natural history, suggest that i.p. administration of CPE inhuman patients harboring recurrent ovarian cancer refractory to chemotherapy may result in reduced toxicity and better therapeutic responses compared with an identical dose of CPE given i.v.

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