FIG. 5.
Knockdown of c-FLIP in HCV core-expressing cells causes TNF-α-mediated apoptosis. (A) HepG2-core cells were transfected with c-FLIP-specific or control siRNA (100 nM). Cell lysates were subjected to Western blot analysis for detection of cFLIP expression levels after 48 h. The level of cellular actin was used as an internal control for comparison. (B) Downregulation of cFLIP correlates with TNF-α-mediated apoptosis. HepG2-core cells transfected with siRNA (100 nM) to cFLIP were treated with TNF-α (20 ng/ml) and analyzed for apoptotic cell death by ELISA (Roche). (C) Western blot analysis of HepG2 control, HepG2-core, or HepG2-FL cells transfected with siRNA (100 nM) to cFLIP and treated with TNF-α (20 ng/ml). Cell lysates were analyzed for expression of caspase-8, c-FLIPL, c-FLIPS, and actin with specific antibodies. Molecular weights of the identified protein bands were validated from the positions of prestained molecular weight markers (Bio-Rad).