Adjuvant effects of prostaglandin D 2 to cisplatin on human ovarian cancer cell growth in nude mice

Abstract

Adjuvant effects of prostaglandin D 2 to cisplatin on tumor growth were studied by using nude mice bearing HR cells derived from human ovarian carcinoma. Combinations of 0.2 or 0.4 μg/ml cisplatin and 0.05 or 0.1 μg/ml prostaglandin D 2, which did not affect the HR cell proliferation alone, resulted in a significant inhibition of cell proliferation. In addition, tumor take of HR cells by nude mice in groups treated with a combination of cisplatin and prostaglandin D 2 was inhibited. Although there was no significant difference between tumor volumes in mice treated with prostaglandin D 2 alone or cisplatin alone and untreated mice, when cisplatin was administered with 1 mg/kg prostaglandin D 2 the tumor volume was significantly smaller on days 21 and 35, compared to that of untreated mice. When cisplatin and 2 or 4 mg/kg prostaglandin D 2 were combined, the tumor growth was significantly inhibited after day 21, compared not only to that of untreated mice but also of mice treated with cisplatin alone or prostaglandin D 2 alone. Such a combination therapy by cisplatin and prostaglandin D 2 seemed to result in prevention by prostaglandin D 2 of immunological suppression which may be induced by cisplatin. Thus, such a combination therapy brought about a significant prolongation to the survival time.