Regulation Of Smac Gene On Chemosensitivity Of Gastric Cancer Cell Line SGC-7901

OBJECTIVES:Abnormal apoptosis is one of the key factors for drug resistance of tumor cells. Smac(second mitochondria-derived activator of caspase) is a new gene involved in regulation of apoptosis found on mitochondrial, released into cytoplasm in the progression of cell apoptosis. Smac promotes cell apoptosis by inhibiting IAP and activating caspase, which plays an important role in tumor cell apoptosis induced by chemotherapeutic drug .This study was designed to explore the expression of Smac gene in SGC-7901 and the impact of overexpression of Smac gene on chemotherapeutic sensitivity of gastric cancer cell line SGC-7901.SUBJECT:human gastric cancer cell line SGC-7901METHODS:By lipofectamine2000, Smac gene was transfected into gastric cancer cell line SGC-7901.Cellular Smac gene expression were determined by reverse transcription-polymerase chain reaction(RT-PCR) and Western blot analysis. Gastric cancer cells were treated with different concentrations of paclitaxel (1,5,10μg / ml) before and after transfection. Cell proliferation activity was detected by MTT colorimetric assay . and cell morphology changes were observed under the inverted microscope and photographed.RESULTS:1.Contrast with non-transfected group and blank vector group, the level of mRNA and protein was significantly higher (P <0.01) in SGC-7901 cells transfected with exogenous Smac gene SGC-7901 cells.2.After treated with different concentration of paclitaxel for 24h and 48h , the rate of growth inhibition of Smac transfected cells was increased apparently contrast with non-transfected group (p <0.01). Smac transfected cells deflated,became irregularity and shrinked,and the proportion of round cells,refractive index and floating cells were increased. The cells growth inhibition rate between non-transfected group and blank vector group has no significant difference(p> 0.05).CONCLUSIONS:1.The Smac gene has weak expression in gastric cancer cell SGC-7901.2.The transfection of Smac gene in human gastric cancer SGC-7901 cells is time-dependent.3.Transfection and overexpression of exogenous Smac gene in SGC-7901 cells enhanced the chemotherapy sensitivity of paclitaxel.