Augmentative effects of intracellular chemotherapy penetration combined with hyperthermia in human ovarian cancer cells lines

A significant proportion of ovarian cancer patients do not achieve a complete response to chemotherapy, due mainly to the evolution of clones resistant to cytotoxic drugs. Exploring possibilities to overcome this resistance constitutes a challenge in the study of ovarian cancer experimental therapy. In the present study, we tested the effect of hyperthermia (40 and 43°C) in combination with adriamycin on three human epithelial ovarian cell lines: OC-109, OC-238, and OC-7-NU. The first was derived from the mucinous and the other two from serous cystadenocarcinomas, and all proved to be tumorigenic in nude mice. FACS analysis showed a pronounced increase in intracellular adriamycin accumulation in the presence of hyperthermia. A significant effect (P < 0.0005) observed at 40°C was even more pronounced at 43°C with the three cell lines. High percentages of cells (up to 70%) shifted into higher fluorescence intensities. The lines differed in their sensitivity to the hyperthermia-induced increase in adriamycin accumulation. Under mild conditions, the OC-109 line was more sensitive than the OC-238 and the OC-7-NU lines. Quantitative determination of intraneoplastic adriamycin by spectrofluorometry also showed a hyperthermia- related increase in intracellular adriamycin (P < 0.005). Our results may indicate that supranormal temperature might serve as an alternative chemosensitizer which lacks the deleterious side effects of other chemosensitizing options.