Knockdown of MTA1 inhibits the proliferation and apoptosis of esophageal cancer cells

Abstract

Objective: To investigate the effects of metastasis associated gene 1 (MTA1) expression on the proliferation and apoptosis of human esophageal cancer Eca109 cells. Methods: MTA1 siRNA was transfected into human esophageal cancer Eca109 cells, and the control group and blank group were set up. The expression of MTA1 in Eca109 cells with different treatment was detected by real-time fluorescent quantitative PCR (RT-PCR) and western blot. The proliferation of Eca109 cells was detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay. The cloning formation ability of Eca109 cells was detected by plate cloning assay. The apoptosis of Eca109 cells were detected by flow cytometry. The expression of proliferating cell nuclear antigen (PCNA) and apoptosis-related proteins, including cleaved caspase-3 and total caspase-3 protein in Eca109 cells were detected by western blot. Results: After 48 hours of transfection, RT-PCR result showed that the relative expression levels of MTA1 mRNA in Eca109 cells in the blank group, control group, and siRNA group were 1.00±0.10, 0.98±0.09 and 0.21±0.03, respectively. The expression of MTA1 mRNA in siRNA group was significantly inhibited (P<0.05), while no significant difference of MTA1 mRNA expression between the blank group and the control group has been found (P>0.05). Western blot results were consistent with those of RT-PCR. MTT array results showed that, compared with the blank group and transfection group, the absorbance values of Eca109 cells in siRNA group were dramatically reduced at 48, 72, and 96 h (all P<0.05). There were no significant differences of absorbance values between the blank group and the control group at 48, 72, and 96 h (all P>0.05). The results of the plate colony formation test showed that the number of colony formation in the blank group and control group were 58.64±6.86 and 60.02±7.04, respectively, significantly higher than 18.10±3.16 in siRNA group (P<0.05), while there was no significant difference between the blank group and control group (P>0.05). Flow cytometry results showed that the apoptosis rates in the blank group and control group were (2.13±0.54)% and (2.27±0.61)%, respectively, significantly lower than (32.61±5.28)% in siRNA group (P<0.05), while there was no significant difference between blank group and control group (P>0.05). Western blot results showed that the expression of PCNA protein was down-regulated while cleaved caspase-3 protein expression was upregulated in siRNA group, compared to the control group and blank group (P<0.05). Conclusions: Inhibition of MTA1 expression can inhibit the proliferation of Eca109 cells and induce apoptosis. This process may be related to the down-regulation of PCNA protein expression and activation of caspase-3 protein expression.