Silencing of Ref-1 Expression by Retrovirus-Mediated shRNA Sensitizes HEK293 Cells to Hydrogen Peroxide-Induced Apoptosis

Abstract

Redox factor-1 (Ref-1) is a multifunctional protein involved in DNA base excision repair (BER) and transcription factor modification. By the use of retrovirus-delivered shRNA, we effectively suppressed endogenous Ref-1 expression in human embryonic kidney (HEK) 293 cells. Our results showed that downregulation of Ref-1 rendered cells more sensitive to H₂O₂-induced apoptosis. In this process, the absence of Ref-1 decreased the ratio of Bcl-2/Bax protein expression, which resulted in cytochrome c release and caspase-3 activation. These data indicate that constitutive Ref-1 is required for cellular defense and that this protective function is dependent on its role in the regulation of Bcl-2 family proteins.