TNF-α up-regulates protein tyrosine phosphatase 1B via NF-kB in HepG2 cells

HepG2 ceils were treated with various concentrations of tumor necrosis factor-or (TNF-α) for 24 hours. RT-PCR and Western blot were used to measure protein tyrosine phosphatase-1 B(PTP-1B)expression, and luciferase reporter assay was used to detect NF-kB activity. The results showed that treatment of HepG2 cells with TNF-α for 24 hours led to upregulation of PTP-1B and NF-kB activity in a dose-dependent manner. Inhibition of NF-kB by PI)TC significantly attenuated TNF-α-induced PTP-IB expression in HepG2 cells. Thus, the transactivation of NF-kB seems to play an important role in the expression of PTP-1B in HepG2 cells induced by TNF-α.