Selenite Enhances and Prolongs the Efficacy of Cisplatin Treatment of Human Ovarian Tumor Xenografts

Background/Aim: Our earlier studies on ovarian tumor xenografts provide evidence that co-treatment with selenite prevents the development of resistance to single-treatment using the drug cisplatin. However, these studies did not reflect the repetitive schedule of clinical chemotherapy. We hypothesized that selenite can enhance the effectiveness of cisplatin during the course of repeated treatments, reflecting clinical practices. Materials and Methods: Multiple i.p. injections of cisplatin (52 mg/kg) alone, or with selenite (1.5 mg/kg), were administered to mice bearing subcutaneous xenografts of human ovarian tumor (A2780) cells and the tumor volume was recorded. Results: Selenite increased and prolonged the efficacy of multiple cisplatin treatments, although selenite was not an effective inhibitor by itself. In the absence of selenite, the effectiveness of cisplatin decreased. Conclusion: The ability of selenite to prolong the effectiveness of repetitive cisplatin treatment, most likely by preventing the development of resistance, makes it a strong candidate for inclusion in clinical trials.