Analysis of Fas and Fas ligand expression and function in lung cancer celllines

The aim of this study was to investigate the expression of Fas and Fas liga nd (FasL) and to determine the significance of these molecules in lung canc er cell lines. Immunoblotting, RT-PCR and flow cytometric analyses were car ried out to measure the expression of Fas and Fast and to examine their int eractions and effects on cell growth and apoptosis. Fas and Fast were coexp ressed in most of the cell lines but to varying degrees. Apoptosis induced by the agonistic anti-Fas antibody was significantly correlated with Fas ex pression (P = 0.0075), whereas cisplatin-induced apoptosis was not. Upregul ation of Fas and Fast expression by the administration of cisplatin was fou nd in 7 of 11 (64%) and 9 of 11 (82%) cell lines, respectively. However, ci splatin-induced apoptosis was not suppressed by antagonistic anti-Fast anti body. Thus, our data indicated that Fas and Fast were co-expressed in lung cancer cell lines, and that Fas ligation induced by agonistic anti-Fas anti body is functional and induced apoptosis that was dependent on the levels o f Fas expression. In contrast, Fas-FasL interactions appeared to be non-fun ctional. Furthermore, our results suggest that cisplatin-induced apoptosis in lung cancer cells was independent of the Fas-Fast interaction. (C) 2000 Elsevier Science Ltd. All rights reserved.