Seocalcitol Inhibits Transforming Growth Factor-Beta1-Inducedepithelial To Mesenchymal Transition In Human Hepatocellular Carcinoma Cell Line SMMC-7721

ObjectiveHepatocellular carcinoma(HCC)is one of the most common 5 types of malignant tumors with high mortality.Each year there are six hundred thousand new cases of HCC in the world.Treatment options for HCC are dependent on many factors;however,surgical intervention remains the leading choice in the comprehensive management.But surgery may not be possible to the patients at late stages of HCC due to tumor extent determined by its invasion and metastasisto surrounding and distal tissues respectively.Recent studies indicate that epithelial to mesenchymal transitions(EMT)promotes the invasion and migration of tumor cells,therefore,the inhibition of EMT could be a new way to treat HCC.Seocalcitol(EB1089)is a newly developed vitamin D analog with accumulating evidence against tumors by its inducing pro-apoptosis and limiting proliferation of tumor cells with minimal effect on the level of the blood calcium.We have hypothesized that seocalcitolinhibits EMT to limit HCC invasion and migration.This study aims to examine the extent of seocalcitolin inhibition of transforming growth factor ?1-induced EMT in human hepatocellular carcinoma cell line SMMC-7721 and explore its underlining mechanisms against HCC.MethodsHuman hepatocellular carcinoma cell line SMMC-7721 was cultured as usual and treated with seocalcitol at 1,10,100,and 1000 nmole/L respectively for 6,12,24,and 48 hours to determine the optimal dose and time of treatment.Then,the SMMC-7721 cells were divided into four groups of control,TGF-?1,seocalcitol,and seocalcitoland TGF-?1.Cell morphology was observed by phase-contrast microscopy.The expression of E-cadherin,N-cadherin,and Vimentin were measured at m RNA and protein levelsby RT-PCR and Western blotting,respectively.Cell invasion and migration were evaluated by Transwell chamber assay.ResultsSeocalcitol treatment at 1000nmol/L for 48 hours is the ideal dose and time to induce highest expression of E-cadherin protein as compared to control group in SMMC-7721 cells.Seocalcitolinhibited TGF-?1-induced cell morphological changes from irregular polygonal to long fusiform.Seocalcitol reversed TGF-?1-down regulated expression of E-cadherin but lowered the expression of N-cadherin and Vimentinboth at m RNA and protein levels,respectively.Seocalcitol limited TGF-?1-induced invasion and migration of the tumor cells.Conclusions1.Seocalcitol inhibits TGF-?1-induced EMT in the hepatocellular carcinoma SMMC-7721 cells.2.Seocalcitol inhibits TGF-?1-induced invasion and migration as well.