BcI-XL Small Interfering RNA Enhances Sensitivity of Hepg2 Hepatocellular Carcinoma Cells to 5-Fluorouracil and Hydroxycamptothecin

Changes in drug sensitivity in Bcl-XL small interfering RNA (siRNA) transfected Hepg2hepatocellular carcinoma cells were investigated in this study.Bcl-XL siRNA and negative siRNA expressionvector were constructed and stably transfected into Hepg2 cells.Reverse transcription (RT)-PCR,westernblot and immunofluorescence were used to detect the target gene expression at mRNA and protein levels.Drug sensitivity of the cells to 5-fluorouracil (5-FU) and hydroxycamptothecin (HCPT) were evaluated withMTT.The Bcl-XL mRNA and protein expression levels in Bcl-XL siRNA transfectants were reducedcompared with negative siRNA transfectants or mock cells.MTT results showed that Bcl-XL siRNAtransfected cells have a higher cell inhibition rate than negative vector transfected cells or untreated cellsafter treatment with 13,130,1300 and 13,000 mg/L of 5-FU.Bcl-XL siRNA transfected cells also showedincreased drug-sensitivity compared with negative vector transfected cells or untreated cells after treatmentwith 0.18,0.36,0.72 and 1.44 mg/L HCPT.Flow cytometry (FCM) results demonstrated that the sub-G1population increased in the Bcl-XL siRNA group,compared with the negative siRNA group and untreatedcontrol group,after the addition of 5-FU (1300 mg/L) and HCPT (0.72 mg/L),siRNA targeting Bcl-XL genecan specifically down-regulate Bcl-XL expression in Hepg2 cells,and can increase spontaneous cell apoptosisand sensitize cells to 5-FU or HCPT.