Neferine induces reactive oxygen species mediated intrinsic pathway of apoptosis in HepG2 cells

Evidence has accumulated concerning the medicinal application of Nelumbo nucifera in the treatment of various diseases. Neferine, an alkaloid from N. nucifera was found to exert cytotoxicity on liver cancer cells HepG2 in a dose-dependent manner. We evaluated its anticancer potential by studying its effect on mitochondrial membrane potential, intracellular calcium levels [Ca(2+)](i), cell membrane integrity, apoptotic body formation and DNA fragmentation in cultured HepG2 cells. The reactive oxygen species level has been increased upon neferine treatment with concomitant decrease in reduced glutathione. Our data further indicate reduction of ΔψM and increased [Ca(2+)](i) during apoptosis induction by neferine with increased expression of apoptotic proteins such as Bax, Bad, cleaved forms of caspase 3, caspase 9 and PARP, with the downregulation of anti-apoptotic protein Bcl2 in HepG2 cells. Moreover, the expressions of tumour suppressor proteins p53 and PTEN were upregulated along with the downregulation of P-Akt. In addition, expression levels of TNF-α, p38 and ERK1/2 MAP kinases were increased upon neferine treatment. These results imply that mitochondrial-mediated ROS generation induced by neferine leads to caspase-dependent apoptosis in HepG2 cells.