Possible Involvement Of Runx3Activity In The Drug Resistance Against Hepatocellular Carcinoma Cells

Objective：To investigate the effect of Runx3activity during drugresistance against hepatocellular carcinoma cells,and further characterize thethe possible mechanisms.Methods： Runx3-shRNA expression vectors were transfected intodrug-resistant HepG₂cells.HepG₂/cisplatin（CDDP） kinetic anti-cancer drugresistance model was constructed using anti-cancer drug inducing methodand treated with5-Aza-2,-deoxycytidine（5-Aza-CdR） for different periodsof time. Reverse transcription-polymerase chain reaction（RT-PCR） was usedto measure Runx3messenger RNA（mRNA） expression level before andafter treatment.The cell viability was evaluated by MTT assy and apotosiswas analyzed using Hoechst33258. Flow cytometry（FCM） was used todetect the cell cycle distribution,Western blot was used to assess the changesin the expression levels of P-gp、Runx3.Results：We observed that down-regulation of expression of Runx3indrug-resistant HepG₂cells promoted the cell proliferation activity,the cellcycle arrested at G1.Mowever,the expression of P-gp increased aftertransfection with Runx3interference plasmids,which indicated that it inhibited the drug sensitivity.The expression of Runx3mRNA decreasedwith the increasing drug resistance against HepG₂cells.However,it increasedgradually after treated with5-Aza-CdR, and cell proliferation was inhibitedobviously.The cells in S phase and apoptotic cells increased.Also,furtherexperiment preliminarily suggested that5-Aza-CdR results in deletion ofP-gp.Conclusion：Our results suggest that Runx3gene may play a inhibitiverole in drug resistance,and up-regulation Runx3make cancer cells moresensitive to chemotherapy.Thus,Runx3may become a new potential targetfor reversing drug-resistant phenotype.