The MicroRNA-34a Efects Biological Behavior Of Esophageal Squamous Cell Carcinoma Cell Line By Targeting Phospholipase C Epsilon-1(PLCE1)

Objective: To investigate the PLCE1 and mi R-34 a expressions in esophageal tumor specimens and adjacent normal esophageal tissues; To explore the regulation of PLCE1 gene by mi R-34 a and its effect on biological function of human ESCC.Methods: Tissue microarrays(TMAs) were used for immunostaining PLCE1 in 207 patients with ESCC. Among these ESCC specimens, 131 specimens that matched the adjacent normal esophageal tissues(NETs) were used as controls. We randomly selected from the samples of 25 pairs of ESCC tissues and NETs.We examined the mi R-34 a expression levels in ESCC tissues and in NETs by q RT-PCR, and analyzed the relationship between mi R-34 a and PLCE1 expressions in ESCC. Cultured ESCC cell lines Eca109 and TE-1. The relative expression levels of mi R-34 a and PLCE1 proteins were quantitated by q RT-PCR and Western Blot before and after tansfect mi R-34 a mimic, mi R-34 a inhibitor or PLCE1 si RNA. Finally, MTT and Colony-formation assays for proliferation,flow cytometry for apoptosis, Transwell assay for migration of ESCC cells. The expression levels of Apoptosis-related proteins and migration-related proteins were also detected by Western blot.Results:(1) The IS of PLCE1 in the ESCC specimens were significantly higher than those in the NETs(p< 0.0001).(2) Relative quantification showed lower expression level of mi R-34 a in ESCC tissues than NETs(p=0.0022), which is negatively correlated with PLCE1 expression(r=-0.4658, p=0.0189).(3)Through dual-luciferase reporter system, co-transfected with mi R-34 a and PLCE1 3’UTR, significantly attenuated the activity of luciferase(p=0.001). In ESCC cell lines, we found that the mi R-34 a regulated the protein expression level of PLCE1 by Western blot.(4)We found that overexpressing mi R-34a/silencing PLCE1 in ESCC cells strongly inhibited cell proliferation and cell migration, induced cell apoptosis, the apoptosis-related protein cleaved-PARP, Caspase-3, cleaved-caspase-3 and Caspase-7 expressions were increased, the ratio of Bcl-2/ Bax was inhibited, and the migration-related protein Snail and Slug also decreased. Mi R-34 a knockdown showed the opposite trend in TE-1 cells.Conclusion: Mi R-34 could target PLCE1 resulted in restrain of proliferation, growth and migration of ESCC cells, inducdtion of apoptosis of ESCC cells. These new findings of our research work may provide novel insights in the clinical treatment of ESCC.