Apoptotic and cytostatic actions of maslinic acid in colorectal cancer cells through possible IKK-β inhibition

Objective:To explore the anti-cancer activity of maslinic acid against colorectal cancer(CRC)cell lines and its possible mechanism.Methods:The inhibitory effect of maslinic acid was screened against five CRC cell lines(HT-29,HCT 116,SW480,SW48,and LS 174 T)via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Apoptosis and cell cycle analyses were carried out using annexinⅤ-FITC/propidium iodide staining and propidium iodide staining,respectively and subjected to fluorescence-activated cell sorting analysis.Protein expression studies of inhibitor ofκB kinase-β(IKK-β),checkpoint kinase 1(Chk1)and cyclin D1 were conducted using the JESS system.Results:Maslinic acid exhibited growth inhibitory effect in a doseand time-dependent manner in HT-29 and HCT 116 cell lines.A more prominent apoptosis induced by maslinic acid was observed in HCT 116 cell line.However,in HT-29 cell line,maslinic acid induced cell cycle arrest by inhibiting the G1-S transition,which was accompanied by the downregulation of cyclin D1.The expression of unphosphorylated IKK-βprotein was increased in both(HT-29 and HCT 116)cell lines after maslinic acid treatment.Conclusions:Maslinic acid inhibits the growth of HT-29 and HCT 116 cells in a different manner,induces cell cycle arrest in HT-29 cells and causes apoptosis in HCT 116 cells partially via NF-κB pathway inhibition.