The Effect Of Downregulating XIAP On Apoptosis, Proliferation And Cell Cycle In Gastric Cancer Cells

Objective:Previous studies found that miR-30a-5p was lower expression in gastric cancer cell lines, and preliminary confirmed that XIAP was the target gene of miR-30a-5p.To investigate the expression of XIAP in human gastric cancer tissues and cells, and the effect of downregulating XIAP on apoptosis, proliferation and cell cycle in gastric cancer cells.Methods:54 gastric cancer tissues compared to adjacent non-tumor tissues including their clinicopathological features were obtained, qRT-PCR was used to detect XIAP mRNA expression in tissue samples. The human gastric epithelial cell line GES-1 as a control, the expression of XIAP mRNA and protein in gastric cancer cell AGS, SGC-7901, MGC-803 and BGC-823 were detected by qRT-PCR and western blot. Two siRNA sequence were designed and synthesized artificially. After transient transfection the above cells, XIAP mRNA and protein were detected again to observe the expression level and interference efficiency compared with si-NC. Three groups of interference cells were stained with Annexin V/PI was used to analyze the effects on cells apoptosis by flow cytometry, proliferation viability was measured by CCK 8 assay, and cell cycle was tested by flow cytometry.Results:XIAP expression in gastric cancer tissues was significantly up-regulated compared to the adjacent non-tumor tissue (P<0.001), and associated with the expression of Her-2 tested by immunohistochemical stain(P<0.01). Cellular XIAP protein expression levels were increased in gastric cancer cell lines AGS, SGC-7901, MGC-803 and BGC-823, compared to gastric mucosa epithelial cells GES-1. However, the relative expression of XIAP mRNA in AGS cells was reduced. After transient transfection, expression level of XIAP mRNA and protein were significantly decreased than negative control group (si-NC) (P<0.05/P<0.01), presents the interference efficiency significantly. Downregulating XIAP aggrandizes apoptosis rates in gastric cancer cells, inhibits cell proliferation in a time-dependent manner (P<0.05/P<0.01), and induced cell arrest in the G0/G1 and (or) G2/M stages.Conclusion:The up-regulated of XIAP was showed in gastric cancer tissues, and associated with the expression of Her-2 tested by immunohistochemical stain. XIAP protein expression were increased in gastric cancer cells, but were varied with the XIAP mRNA expression. Downregulating XIAP can promote apoptosis, inhibit cell proliferation, and induce GO/G1 and (or) G2/M cell arrest in gastric cancer cells.