Study The Expression Of TAZ In Non-small Cell Lung Cancer Tissue And TAZ Gene Silence On The Proliferation And Potosis Of Human Lung Adenocarcinoma Lines

Background and Objective:Lung cancer is the most common cancer worldwide, Despite the advance ment in surgical, radio-and chemo-therapies over the years,the5-year survival rate of lung cancer remains<15%, Of lung cancers diagnosed, over80%re non-small cell lung cancer (NSCLC). although many tumor suppressor genes (for example, p53, Rb, pl6and so on) and oncogenes(EGFR, Kras, Cyclin D and so on) important for the development of NSCLC have been identified; the majority of NSCLC patients are usually diagnosed during the later stages of lung cancer and die without successful treatment.Therefore, the identification of new proteins responsible for NSCLC progression is critical for both early detection and the development of novel therapeutic approaches for the successful treatment of lung cancer. TAZ, also called WW-domain containing transcription regulator1(WWTR1), is a WW domain-containing transcriptional coactivator that activates many transcriptional factors which have important roles in the development of various tissue in mammals, TAZ has also been shown to regulate stem cell differentiation and renewal through modulation of the transcription factors. Recent studies have shown that TAZ was overexpressed in breast cancer,thyroid cancer and NSCLC cell lines, as a carcinogenic factor was involved in the development of tumor, but its expression in non-small cell lung cancer was reported little,To be further studied. RNA interference (RNAi) phenomenon is the double-stranded RNA(dsRNA) triggered widespread in vivo that target gene sequences were silenced by sequence-specific gene segment, therefore studying small interfering RNA (siRNA) of TAZ silenced expression in NSCLC, is expected to provide a new ideas and methods for the treatment of NSCLC.This study investigate the expression of TAZ mRNA,protein and its clinical signifycance in non-small cell lung cancer, and the role of TAZ siRNA on the proliferation and apotosis of human lung adenocarcinoma NCI-H157cells. To provide a new theoretical basis for exploring the developmental mechanism and clinical treatment in non-small cell lung cancer.Methods:The experimental group included58specimens of NSCLC and58specimens of lymph nodes. The control group included58specimens of distal cancerous tissues, peritumoral tissues and22samples of benign pulmonary disease. We evaluated the expression of TAZ mRNA and protein in58specimens of NSCLC cases, distal cancerous tissues and20specimens of lung benign disease cases using real-time qPCR and Western blotting;The expression of TAZ protein in42specimens of NSCLC,58specimens of lymph nodes and7specimens of benign pulmonary disease were studied by immunohistochemical technique;TAZ small interfering RNA(TAZ-siRNA)was transfected into human lung adenocarcinoma NCI-H157cells by cationic liposome transfection method, The cells were divided into4groups:experimental group with TAZ-siRNA, negative control group with siRNA that did not impact any gene, blank control group without any transfection and Mock transfection group. The expression level of TAZ mRNA and protein were examined by real-time quantitative PCR and Western blot. Counted in each group at different time points cell number and described the cell growth curve, cell propagation and apotosis were analyzed by MTT adhension assay and flow cytometry.Results:The real-time qPCR study demonstrated that the level of TAZ mRNA in NSCLC was significantly higher than the distal cancerous ones or lung benign disease group(<0.05),A significant difference was detected by Western blot, between the TAZ protein expression of NSCLC cases and control group cases; in42specimens of NSCLC tissue, the expression of TAZ protein was mainly localized in the nucleus and cytoplasm, while in peritumoral tissues and benign pulmonary disease, the expression of TAZ protein was mainly localized in the nucleus, the localized expression of TAZ protein between the two groups were significantly different (P=0.001, P=0.000);Among the58detected lymph nodes,26were found with metastasis, The positive rates of TAZ in lymph nodes with metastasis were88%(23/26), significantly higher than those in lymph nodes without metastasis(16/32)(P=0.002); The expression of TAZ mRNA in NSCLC was associated with tumor size, differentiation degree, and p-TNM stage (P<0.05), The positive position of TAZ protein in patients with NSCLC was associated with differentiation degree and p-TNM stage(P<0.05);TAZ mRNA and protein were significantly decreased by TAZsiRNA, rate of protein inhibits were62.1%,64.9%and60.9%. The ability of cell propagation was decreased in experimental group, transfected after24and48hours, Gl phase arrest was shown in the experimental group.Conclusions:The expression of TAZ mRNA and protein was higher in non-small cell lung cancer,The ectopic of TAZ protein expression in patients with NSCLC may participate in tumorigenesis and development,Under appropriate conditions, TAZ gene can be silenced by siRNA in human lung adenocarcinoma NCI-H157cells, The ability of cell propagation was inhibited too. That means TAZ gene may be a key molecule in development of NSCLC and regulate the biological process of NSCLC, It may become a new molecular targets in treatment of NSCLC.