[Overexpression of Smac gene enhanced chemotherapeutic sensitivity of esophageal cancer cell line Eca109 to cisplatin].

AIM: To investigate the effects of Smac gene overexpression on chemotherapeutic sensitivity of esophageal cancer cell line Eca109 to cisplatin.

METHODS: pcDNA3.1-Smac with GFP and pcDNA3.1-Smac with GFP were transfected into esophageal cancer cell line Eca109 by liposome and incubated with G418 for subclone selection.The efficiency of transfection was observed under fluorescence microscope, cellular Smac gene expression were determined by Western blot. Cisplatin treated group (1, 5, 10 mg/L) and cisplatin untreated group were selected to treat untransfected and transfected esophageal cancer cell line Eca109. Apoptosis was determined by Annexin V/PI.

RESULTS: The subclone esophageal cancer cell line Eca109, stable expressing Smac+GFP and neo+GFP respectively, were successfully selected, named as Eca109/Smac, Eca109/neo. Compared with the Eca109/neo and Eca109, the Smac expression level of Eca109/Smac was significantly increased(P<0.05). In cisplatin untreated group, the apoptosis rate was not associated with Smac expression. In cisplatin treated group (1, 5, 10 mg/L), compared with Eca109/neo and Eca109, the apoptosis rate of the Eca109/Smac was significantly increased after the treatments of cisplatin, the difference were significant(P<0.05). In addition, the apoptosis rate of Eca109/Smac was significantly increased with the concentration of cispaltin increased(P<0.05). The difference between Eca109/neo and Eca109 were not significant.

CONCLUSION: Smac gene didn't induce apoptosis in the cisplatin untreated Eca109 cells. Smac gene overexpression could increase chemotherapeutic sensitivity of esophageal cancer cell line Eca109 to cisplatin.