Effectiveness of antineoplastic drugs on the proliferation of human mammary and ovarian carcinoma cells in monolayer culture.

Procedures for the in vitro determination of the drug-induced inhibition of mammary and ovarian carcinoma cell growth were established. In monolayer cultures derived from advanced tumors, separation of epithelial carcinoma cells from concomitant cells of fibroblast-like or mesothelial appearance was achieved by differential trypsinization. The carcinoma cell character of the stock cultures was verified by chromosome analyses showing a high degree of aneuploidy for the epitheloid cell lines and euploidy for cells of apparently mesenchymal origin. When cultured carcinoma cells were injected in nu/nu mice, the tissue and cell cultures obtained from the heterotransplantation tumors closely resembled the original tumors and cell cultures in morphology, karyotype, and expression of tumor markers. The action of carcinostatic drugs in the logarithmic phase of the carcinoma cell proliferation was tested by kinetics experiments in multiple experimental cultures. In cell proliferation assays based on cell counts the 50% inhibition dose (ID50) of the drug effects was determined from the dose-response curves. Comparison of the ID50s revealed highly differential effectiveness of the drugs examined. The inhibitory effects were reproducible, rendering the procedures used suitable for testing the chemosensitivity of newly explanted gynecological carcinoma cells by proliferation assays.