Abstract: This work mainly investigated the effects of Arenobufagin (ArBu) on the viability and apoptosis of non-small cell lung cancer (NSCLC) cells and explored the mechanisms of ArBu-induced apoptosis.Taken NSCLC cells PC-9 as a study model,MTT assay was performed to detect the inhibitory effects of ArBu on PC-9.The results showed that ArBu significantly suppressed the growth of PC-9 cells at various concentrations and treating times.Hoechst 33258 staining demonstrated that ArBu -treatment reduced the cell number,caused chromatin condensation,nucleic fragmentation and apoptotic body formation，indicating the induction of apoptosis.Furthermore,the results of flow cytometry showed that a significant quantitative relationship between apoptosis and the concentrations of ArBu.In addition,western blot detected decreased phosphorylation of EGFR/RAF/MEK/ERK signal pathway proteins,down-regulated expression of anti-apoptotic protein Bcl-2,and up-regulated expression of apoptotic protein Bax in ArBu-treated cells.These results demonstrated that ArBu can significantly decrease the viability and induce apoptosis of PC-9 cells,suggesting that ArBu has the potential to be further studied as a leader compound for the treatment of lung cancer.

Key words: Arenobufagin, EGFR, lung cancer, apoptosis