Radiosensitization of a mouse melanoma by withaferin A: <i>In vivo </i>studies

Abstract

The radiosensitizing effect of a plant withanolide, withaferin A, on the B16F1 mouse melanoma was studied <i>in vivo.</i>Treatment of 100 mm³ tumours with 10 to 60 mg/kg withaferin A intraperitoneally produced a dose dependent increase in<i> </i>growth delay and volume doubling time. Injection of 30-50 mg/kg withaferin A, followed by 30 Gy local gamma irradiation,<i> </i>significantly enhanced the tumour response. No systemic or local adverse reactions were noted in these groups. The drug<i> </i>was most effective when injected intraperitoneally 1 h before irradiation. However, neither the individual agents nor their

combination could produce any complete response (tumour cure). Melanoma is a relatively radioresistant tumour. The present results indicate that the radiation response of this tumour can be significantly enhanced by pretreatment with withaferin A.