Amfenac increases the radiosensitivity of uveal melanoma cell lines

Abstract

Purpose: To evaluate the proliferation rates of five human uveal melanoma (UM) cell lines after treatment with amfenac, a cyclooxygenase (COX)-2 inhibitor, and subsequent radiation exposure. Methods: Five human UM cell lines (92.1, SP6.5, MKT-BR, OCM-1, and UW-1) and one human fibroblast cell line (BJ) were incubated with amfenac. Treated and non-treated cell lines were then exposed to various doses of γradiation: 0, 2, 4, 6, and 8Gy. Sulphorhodamine-B assay was used to assess proliferation rates 48h post-radiation. Results: Treatment ofUM cell lines with amfenac prior to radiation led to a marked reduction in proliferation rates. This difference was statistically significant in all cell lines at every radiation dose (P<0.005), with the exception of 92.1 at 2Gy (P=0.157). Fibroblasts treated with amfenac showed significantly higher proliferation rates after 2 and 8Gy, with no significant differences at 0, 4, and 6Gy. Conclusions: The radiosensitivity of UM cell lines was increased by the administration of amfenac, the active metabolite of nepafenac. There appears to be a radioprotective effect of amfenac on human fibroblasts. The topical administration of nepafenac may decrease tumour recurrence and radiation-induced complications while broadening the indications for radiotherapy by treating larger tumours.