Expression Of PLCE1 In Esophageal Cancer And Its Effect On The Proliferation And Invasion Of Esophageal Cancer Cell Lines

Objective: To investigated the PLCE1 expression in esophageal tumor specimens and adjacent normal esophageal tissues; to observe the effects of down-regulation of PLCE1 expression gene on proliferation and invision of esophageal carcinma cells.Methods: Tissue microarrays(TMAs) were used for immunostaining PLCE1 in 100 Han ethnic patients with ESCC. Among the 100 ESCC specimens, 99 specimens that matched the adjacent normal esophageal tissues(NETs) were used as controls. Using q RT-PCR, western blot analysis and immunofluorescence were taken to know about inhibition of PLCE1 expression in Eca109 and EC9706. We attempted knockdown PLCE1 using PLCE1-si RNA, after 48 h, to investigate the proliferation of PLCE1 in esophageal squamous cell, MTT assay to measurement cell growth rate, colony-formation assays to measure cell proliferation rate, flow cytometric analysis to measurement cell apoptosis, and transwell chamber invasion assay to measurement cell invasion of two different ESCC cell lines, Eca109 and EC9706.Results:(1) The IS of PLCE1 in the ESCC specimens was significantly higher than those in the non-malignant specimens. In addition, increased expression of PLCE1 was correlated with advanced TNM stages and lymph node metastasis in patients with ESCC; Kaplan-Meier survival analysis revealed that the overall survival was significantly lower in patients with high PLCE1 expression than in patients with low PLCE1 expression.(2) The result of q RT-PCR, western blot analysis and immunofluorescence showed that PLCE1 m RNA and protein levels were successfully reduced by transfection of specific si RNA against PLCE1. Proliferation of Eca109 and EC9706 cells decreased in si-PLCE1 transfected cells compared with the respective controls. Colony-formation assays showed a similar pattern to that MTT. The number of colonies decreased following the downregulation of PLCE1 in the two different ESCC cell lines. Flow cytometric analysis results showed that the early apoptosis rate increased in Eca-109-si-PLCE1 and EC9706-si-PLCE1-cells, respectively. Western blot analysis showed that the apoptosis-related protein Bax and cleaved-PARP increased, the expression of BCL-2 decreased. The tumor cell invasion assay indicated that transfection of si-PLCE1 could reduce the invasion power of the ESCC cell line. The epithelial marker E-cadherin was significantly upregulated, whereas the mesenchymal marker vimentin was significantly reduced in cells with knockdown of PLCE1 compared with the control si RNA groups.Conclusion:(1) The expression of PLCE1 increased in ESCC than in the NETs, high PLCE1 levels in ESCC are significantly correlated lymph node metastasis and advanced TNM stages of ESCC, and Kaplan-Meier survival analysis revealed that the overall survival was significantly lower in patients with high PLCE1 expression than in patients with low PLCE1 expression.(2) Downregulation of PLCE1 suppresses ESCC cells growth and induces apoptosis, indicating that PLCE1 may be involved in the regulation of proliferation. Downregulation of PLCE1 may suppresses ESCC cells invasion power by regulating the epithelial mesenchymal transition.