The mechanism of cancer cell type-specific regulation of radiation-induced apoptosis by cAMP signaling

Abstract

cAMP signaling regulates apoptosis of various cancer cells, but the effect was different depending on the cell types. We investigated the difference in the mechanism for cAMP signaling to regulate apoptosis. The activation of cAMP signaling by treatment with forskolin in H1299 ling cancer cells augmented radiation-induced apoptosis with an increase in Bax expression and a decrease in Bcl-xL. In contrast, treatment of HeLa uterine cervical cancer cells with forskolin inhibited radiation-induced apoptosis with an increase in Bcl-2, Bcl-xL, and XIAP. The activation of cAMP signaling increased XIAP mRNA expression in HeLa cells, but not in H1299 cells. It is concluded that cAMP signaling exhibits different effects on radiation-induced apoptosis by differential expression of apoptosis-regulating protein in different cancer cell lines.