Romidepsin (FK228) combined with cisplatin stimulates DNA damage-induced cell death in ovarian cancer

ObjectiveRomidepsin (FK228) was recently approved by the FDA for the treatment of cutaneous and peripheral T cell lymphoma. We have shown in vitro efficacy of FK228 in ovarian cancer. Here, our goal was to evaluate FK228 combined with cisplatin in ovarian cancer in vitro and in vivo.MethodsOvarian cancer cell lines were treated with cisplatin, FK228 or the combination of drugs. Colorimetric assays were used to determine cytotoxicity in vitro. Mice engrafted with 5 × 106 SKOV-3 ovarian cancer cells were treated with cisplatin, FK228 or the combination, and tumor weights and volumes were measured. We assessed molecular markers of proliferation (mib-1), apoptosis (cleaved PARP and cleaved caspase 3) and DNA damage (pH2AX, RAD51 and 53BP1).ResultsFK228 enhanced the cytotoxic effects of cisplatin in ovarian cells compared to vehicle-treated controls or each drug alone. The combination of FK228 and cisplatin‐induced apoptosis and activated aberrant DNA damage responses demonstrated by increased expression of pH2AX, RAD51 and 53BP1. Mice treated with FK228, cisplatin and both drugs showed reduced tumor weights and volumes. Drug-treated tumors showed decreased mib-1 and increased cleaved-caspase 3 expression levels. The number and intensity of pH2AX stained cells was greatest in tumors exposed to the combination of FK228 and cisplatin.ConclusionFK228 causes DNA damage-induced apoptosis and enhances the anti-tumor effects of cisplatin. The DNA damage mark pH2AX is activated by FK228 and cisplatin and may be a useful pharmacodynamic mark of these effects.

► FK228 combined with cisplatin augments DNA damage-induced apoptosis in ovarian cancer cells. ► The DNA damage response protein pH2AX is activated by FK228 and cisplatin in vitro and in vivo. ► pH2AX may be a useful pharmacodynamic mark of FK228-based therapy.