Development of a syngeneic mouse model for events related to ovarian cancer

Abstract

Mouse ovarian surface epithelial cells (MOSEC) were obtained from virgin, mature mice by mild trypsinization and were repeatedly passaged in vitro. Early passage cells (<20 passages) exhibited a cobblestone morphology and contact inhibition of growth. After approximately 20 passages in vitro, cobblestone morphology and contact inhibition of growth was lost. Tumor forming potential was determined by s.c. and i.p. injection of early and late passage cells into athymic and syngeneic C57BL6 mice. Subcutaneous tumors formed in approximately 4 months and were present only at the injection site. Intraperitoneal injection of late passage MOSEC into athymic and syngeneic mice resulted in growth of tumor implants throughout the abdominal cavity, and production of hemorrhagic ascitic fluid. Early passage MOSEC did not form tumors in vivo. Histopathologic analysis of tumors revealed a highly malignant neoplasm containing both carcinomatous and sarcomatous components. Late passage MOSEC expressed cytokeratin and did not produce ovarian steroids in response to gonadotropin stimulation in vitro. Ten clonal lines were established from late passage MOSEC. Each clone formed multiple peritoneal tumors and ascitic fluid after i.p. injection into C57BL6 mice. Three cell lines examined cytogenetically were polyploid with near-tetraploid modal chromosome numbers. Common clonal chromosome gains and losses included +5, +15, +19 and -X, -3, -4. One cell line had a clonal translocation between chromosomes 15 and 18 and another had a small marker chromosome; common structural abnormalities were not observed. These data describe the development of a mouse model for the study of events related to ovarian cancer in humans. The ability of the MOSEC to form extensive tumors within the peritoneal cavity, similar to those seen in women with Stage III and IV cancer, and the ability of the MOSEC to produce tumors in mice with intact immune systems, makes this model unique for investigations of molecular and immune interactions in ovarian cancer development.

Antigen-Specific Immunity and Cross-Priming by Epithelial Ovarian Carcinoma-Induced CD11b+Gr-1+ Cells

“…injection of 10 million ID8 cells, a mouse epithelial ovarian cancer cell line (25,28), the mice usually began to develop cancerous ascites starting at 7 wk postinjection. Mice that developed ascites were easily distinguished by a brief external examination, because they exhibited abnormal swelling in the abdomen.…”

Oncolytic virotherapy for ovarian carcinomatosis using a replication-selective vaccinia virus armed with a yeast cytosine deaminase gene

“…The MOSEC cancer cell line (clone ID8) was a kind gift from Dr K Roby of the University of Kansas. 38 Other cell lines such as HeLa, MC38, CV-1 cells and human primary fibroblast cells MRC-5 (ATCC) have been frequently used in our laboratory. All cell lines were maintained in Dulbecco's modified Eagle's medium supplemented with 10% heat-inactivated bovine calf serum, 2 mM glutamine and penicillin/streptomycin (100 U ml À1 and 100 mg ml À1 , respectively) in an incubator at 37 1C with 5% CO 2 , and were serially passaged every 3-4 days.…”

“…These characteristics make this model particularly attractive as it mimics the disease seen in women with late-stage ovarian cancer. 38 Thus, we performed experiments utilizing this murine ovarian carcinomatosis model in syngeneic C57BL/6 mice ( Figure 6). The MOSEC tumor-bearing C57BL/6 mice treated with vvDD-CD (1.0 Â 10 9 PFU/mouse) on the day of tumor cell inoculation displayed a highly significant survival advantage compared with controls (Po1.0 Â 10eÀ6) (Figure 6a).…”

Lysophosphatidic acid stimulates cell migration, invasion, and colony formation as well as tumorigenesis/metastasis of mouse ovarian cancer in immunocompetent mice

“…Roby et al have established mouse EOC cell lines using mouse ovarian surface epithelial cells isolated from normal mouse ovaries through repetitive passaging and spontaneous transformation in vitro (33). Ten clonal cell lines were established with distinguishable chromosomal changes and tumorigenic potential.…”

“…Among these cell lines, ID8 cells form tumors in syngeneic C57/BL6 mice with the highest incidence and shortest lag time when i.p. injected (33). Mouse ovarian surface epithelial cells can be used in immunocompetent mice.…”