Effect of ECRG2 in combination with cisplatin on the proliferation and apoptosis of EC9706 cells

The aim of the present study was to explore the effect of esophageal cancer-related gene 2 (ECRG2) protein in combination with cisplatin (DDP) on the proliferation and apoptosis of esophageal cancer cells. A 3-(4, 5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay was used to examine the effects of ECRG2 alone and ECRG2 in combination with DDP on the proliferation of EC9706 esophageal cancer cells. Hoechst 33258 staining was performed to analyze the effects of ECRG2 alone and ECRG2 in combination with DDP on apoptosis in the EC9706 cells. The expression levels of Bcl-2-associated X protein (Bax) mRNA and protein were determined by reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively. The results from the MTT assay revealed that ECRG2 inhibited the proliferation of EC9706 cells and that ECRG2 in combination with DDP had a greater inhibitory effect on cell proliferation. The antiproliferative effects were time- and concentration-dependent, within a certain range of concentrations. The Hoechst 33258 staining results demonstrated that the number of apoptotic cells following treatment with ECRG2 in combination with DDP for 24 h was higher than that following treatment with ECRG2 alone for the same duration. Western blot analysis and RT-PCR results revealed that the expression levels of Bax mRNA and protein were upregulated in cells treated with ECRG2 in combination with DDP compared with those in cells treated with ECRG2 alone. Thus, ECRG2 in combination with DDP had an enhanced inhibitory effect on EC9706 cell proliferation compared with that of ECRG2 alone, and an increased inductive effect on EC9706 cell apoptosis, possibly due to the upregulation of the expression of Bax.