Human ovarian tumors in primary culture: Growth, characterization and initial evaluation of the response to cis platinum treatment in vitro

A novel cell culture system is reported for the growth of ovarian tumors. Two approaches were developed to isolate tumor cells, one for ovarian carcinomas and the other for benign cystomas or borderline cystadenomas, which yield virtually pure tumor-cell clusters. The plating efficiency exceeded 10% in approximately 80% of the processed surgical specimens. Cells grown in a newly developed KOV medium (a modification of MCDB 151 supplemented with 6 defined growth factors and a moderate amount of FBS) had an average growth rate of 0.23 population doublings/day. Primary tumor-derived cultures, including those derived from cystomas, were analyzed by flow cytometry demonstrating a DNA heteroploid content in 55% of the cases. The neoplastic origin of the cells in culture was further confirmed by 3 monoclonal antibodies (OC125; MOv2; MOv19) with high specificity against epithelial ovarian malignancies. Cultures were tested with cis-DDP to determine their suitability for pharmacological studies. Exposure to the drug (from 10 to 80 microM for 1 hr) resulted in variable cell-killing responses, and the prominent effect on cell-cycle progression in primary cultures was a prolonged arrest in S phase. The formation and persistence of DNA-ISC caused by an exposure to 40 microM cis-DDP for 1 hr was studied by alkaline elution in 6 different tumor-derived cultures. DNA-ISC equivalents were highest between 9 and 24 hr after treatment and were repaired only to a limited extent within 48 hr of recovery time. The present study confirms the usefulness of this culture system for pharmacological studies of active chemotherapeutic agents against human ovarian tumors.