Simultaneous soft agar cloning of ascites and solid tumor specimens from patients with ovarian cancer

Immortalized bovine pancreatic duct cells become tumorigenic after transfection with mutant k-ras

Mutation of the K-ras gene is thought to be an early and important event in pancreatic carcinogenesis. In order to study the role of this molecular alteration in the transition from the normal to the neoplastic pancreatic cell, bovine pancreatic duct cells were first immortalized by SV40 large T antigen (Ag) complementary (c)DNA transfection and then transfected with a mutated K-ras gene. As did primary duct cells, the immortalized duct cells (more than 100 passages) expressed cytokeratins, carbonic anhydrase type-II, cystic fibrosis transmembrane conductance regulator (CFTR), and multidrug resistance (mdr). They grew as a single layer after transplantation under plastic domes and formed three-dimensional structures resembling ducts when grown on Matrigel. Cell growth was stimulated by insulin, epidermal growth factor (EGF), transforming growth factor (TGF)-alpha, but cells did not respond to gastrin and CCK-8. They did not form colonies in soft agar nor did they form tumors in nude mice. Immortalized cells transfected with mutated K-ras acquired the ability to form tumors after orthotopic injection into the nude mouse pancreas. It is concluded that SV 40 immortalized bovine pancreatic

Phenotypic variations and differential migration of NIH:OVCAR-3 ovarian carcinoma cells isolated from athymic mice

Transplantation of the human ovarian adenocarcinoma cell line, NIH:OVCAR-3 into athymic mice produces two morphologically distinct tumor cell populations (ascites and solid tumors). In the present study, we isolated both tumor cell phenotypes and investigated their relative malignant potential. Since cytoskeletal and morphological changes correlate with metastatic phenotype, expression of the intermediate-filament protein vimentin was compared between ascites and solid tumors. Ascites tumor cells showed a less differentiated epithelial morphology and concurrently expressed higher levels of vimentin. Ascites cells were more efficient in anchorage independent growth when compared with their solid tumor counterpart. Ascites tumor cells were also highly motile compared with the solid tumor cell population (P = 0.006). Migration of ascites tumor cells was further enhanced by type IV collagen, hyaluronic acid, and chondroitin sulfate A. Solid tumor cells removed from the same animal, however, were not significantly affected by these agents. From these studies, we conclude that ovarian cancer cells present in ascites are phenotypic variants which are highly motile compared with solid tumor cells isolated from the same animal. Ascites tumor cells with increased motility may contribute to peritoneal seeding and metastasis.

Relationship between the in vitro colony growth of human tumors and cytologic diagnosis

The cytologic examinations and cloning efficiencies of 47 human tumor specimens (19 ovarian carcinomas, 6 sarcomas, 5 lung carcinomas, and 17 miscellaneous tumors) were compared to evaluate the predictability of clonogenecity by cytologic diagnosis. Cytologic examination preceding clonogenic assay identified the 50% to 60% of all specimens that failed to yield in vitro chemotherapy sensitivity by this assay, with a false-negative rate of 10%. The frequency of cytologically identifiable tumor cells in the plating suspension was independent of the histologic type of tumor (ovarian carcinoma or others) and the nature of the specimen (solid tumor or malignant effusion). Nearly 66% of all specimens were cytologically negative. The in vitro sensitivity can be assessed in approximately 75% of cytologically positive specimens. Cytologic evaluation preceding soft-agar clonogenic assay of human tumors can reduce cost and effort by predicting colony-producing specimens.