Antitumor activity of new organometallic compounds in human ovarian cancer cell lines and comparison to platin derivatives

Cisplatin, Carboplatin and new compounds such as Paclitaxel and Docetaxel are effective drugs in the treatment of ovarian cancer. Multidrug resistance however remains an issue in ovarian cancer. The search for new effective drugs will remain of the highest priority in the field of cancer research. The in vitro and in vivo growth inhibiting potencies of two new metallocene dichlorides, Titanocendichloride and Vanadocendichloride, were compared to Cisplatin and Carboplatin using 20 permanent human ovarian cancer cell lines. Under in vivo and in vitro conditions Cisplatin was more effective than Carboplatin. Under in vitro conditions a Vanadocendichloride concentration of as low as 1.5 x 10(-7) mol/l resulted in a 50% decrease in the cell proliferation. Titanocendichloride inhibited cellular growth only at concentrations of 10(-4) mol/l. In contrast, Titanocendichloride was more effective in inhibiting growth of xenotransplanted ovarian cancer cell lines in nude mice. The clinically supposed equipotentiality of Carboplatin should be handled cautiously. The new organometallic substances clearly exhibit antiproliferative properties in ovarian cancer cells and are considered for clinical phase I trials.