Inhibition Of Notch1 Pathway Is Involved In Rottlerin-induced Tumor Suppressive Function In Nasopharyngeal Carcinoma Cells

ObjectiveRottlerin is a natural polyphenolic compound from the mature fruits of Mallotus philippinensis.Recent studies have researched that Rorrlerin could be some protein kinases inhibitors,and as a natural chemical drugs to exert anti-cancer activity in many cancers.However,the underlying mechanisms of Rottlerin-induced anti-tumor activity are not fully elucidated.Notch1 played a crucial oncogenic role in many cancers.Then,inactivation of Notch1 could be a beneficial approach for the treatment of human cancer.The aims of our study were to explore whether Rottlerin could suppress Notch1 expression and subsequently exert anti-cancer biological effects.Methods1.The cell proliferation was measured by CTG assay in nasopharyngeal carcinoma cells after Rottlerin treatment.2.The cell apoptosis and cycle were analyzed by flow cytometry in nasopharyngeal carcinoma cells after Rottlerin treatment.3.The ability of migration and invasion was judged by wound-healing assay and Transwell assay in nasopharyngeal carcinoma cells after Rottlerin treatment.4.The expression of Notch1 protein was detected by Western blot in nasopharyngeal carcinoma cells after Rottlerin treatment.5.Over-expression or down-expression of Notch1 was performed by transfection of Notch1 plasmid or small interfering RNA(si RNA),then to explore the molecular mechanisms of Rottlerin-suppressed nasopharyngeal carcinoma cells.Results1.Rottlerin could inhibit CNE1 and CNE2 cells proliferation ability,and this inhibitory effect was in time-dependent and dose-dependent manners.With the increase of drug concentration and expand of treatment time,the growth of nasopharyngeal carcinoma cells was suppressed more obvious.2.Rottlerin could induce apoptosis and arrest cell cycle at G1 phase in CNE1 and CNE2 cells.3.Rottlerin could inhibit the ability of migration and invasion in CNE1 and CNE2 cells.4.Rottlerin could decrease the expression of Notch1 protein in CNE1 and CNE2 cells.5.Over-expression of Notch1 abrogated Rottlerin-mediated anti-tumor activity,such as enhanced cell growth,induced cell migration and invasion in CNE1 and CNE2 cells.6.Down-expression of Notch1 enhanced Rottlerin-mediated antitumor effect,such as inhibited cell proliferation,rescued cell migration and invasion in CNE1 and CNE2 cells.ConclusionsOur found that Rottlerin significantly inhibited the proliferation,induced the apoptosis,arrested the cell cycle,suppressed the migration and invasion,reduced the expression Notch1 protein in nasopharyngeal carcinoma cells.So Rottlerin processed the anti-tumor activity.Through the over-expression and down-expression of Notch1,we future identified that Rottlerin exhibited its anti-cancer potential partly by regulation of Notch1 in nasopharyngeal carcinoma cells.Strikingly,our study implied that Notch1 could be a useful target of Rottlerin for the prevention and treatment human nasopharyngeal carcinoma.