RESUMEN
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) serves as an extracellular signal triggering apoptosis in tumor cells. To characterize the molecular events involved in TRAIL-induced apoptotic signaling, we investigated the role of extracellular signal-regulated kinase 1/2(ERK1/2) in the apoptosis using HeLa cells. Here we show that TRAIL pronounced ERK1/2 activation through a tyrosine kinase-dependent mechanism, subsequently elevated anti-apoptotic Bcl-2 protein levels. Pretreatment with Genistein, an inhibitor of tyrosine kinase, significantly attenuated ERK1/2 activation and enhanced cell death. Moreover, inhibition of ERK1/2 with PD98059 promoted apoptotic cell death through the down-regulation of ERK1/2 activity and Bcl-2 protein levels. Taken together, our results suggest that the activation of ERK1/2 via tyrosine kinase pathway plays a protective role as the mechanism of cellular defense through the up-regulation of Bcl-2 protein levels in TRAIL-induced apoptosis.