Study On The Role Of Transgelin In The Progression Of Lung Adenocarcinoma

Background and objective:Lung cancer is the leading cause of cancer-related deaths worldwide. Due to no methods for the early detection and no effective treatment of lung cancer, the high mortality rate of lung cancer is still not improvement and the survival rate of5years is only17%。In recent years, with the development of molecular biology and genetic engineering, intensive efforts are underway to study the possible molecular mechanisms and therapeutics at the level of genes.Transgelin is a shape-change sensitive22KDa actin-binding protein of the calponin family. Some previous studies show it might have tumorigenic role, because its expression is increased in several cancers, for example, in pancreatic or colorectal cancer. In addition, our previous study showed that transgelin is upregulated in lung cancer compared to the adjacent normal lung tissues. This indicated that transgelin might play an important role in the development of lung cancer. Based on our previous data, we knockdown the expression of transgelin in A549by lentivirus, and investigate the effect on the growth of established lung cancer xenograft in nude mice. Besides, the expression pattern and clinicopathological significance of transgelin protein in lung adenocarcinoma tissues was analyzed.MethodsFirst, human lung adenocarcinoma cancer cell lines A549was transfected with lentiviral shRNA targeting transgelin gene. Real-Time PCR and Western blot were used to analyze transgelin expression after transfection. Then3groups of subcutaneous lung adenocarcinoma xenografts were established by inoculating different disposal A549cells:One group with cells with lentivirus encoding shRNA targeting transgelin (the experimental group), one with cells transfected with non-transfected lentivirus vectors (the negative group), and another were untreated A549cells (the blank control group). Tumor size was measured every5days. All mice were sacrificed after30days. The tumor volume and weight of these tumors were measured. Inhibition rate was calculated. Tansgelin and proliferating cell nuclear antigen (PCNA) proteins expression were detected by immunohistochemistry assay. In addition, tissue microarray and immunohistochemistry were performed to detect the expression of transgelin and analysis the clinicopatho logical significance in adenocarcinoma.Results(1) Subcutaneous lung adenocarcinoma xenografts in3groups were successfully established. The tumor growth in experimental group was significantly slower than the blank and negative groups (p<0.05). The tumor volume in experimental group was also significantly smaller compared with other two groups (p<0.05). Tumor weighted in experimental group were much lower than the negative and blank groups (p<0.05). The inhibiton rate was75%.(2) Transgelin protein expression level in the experimental group was significantly lower compared with the negative and blank groups, indicating successfully knockdown the expression of transgelin in the experimental group. In addition, PCNA protein expression was significantly lower than other two groups (all p<0.05).(3) The expression rates of TAGLN protein in tumor tissue (51/75,68%) was significantly increased compared to the adjacent tumor-free tissue (30/75,40%)(p=0.001, x2=11.836).(4) Transgelin expression was strongly associated with tumor stage (p=0.023, x2=6.117), lymph node status (p=0.025, x2=5.672) and differentiation grade (p=0.014, x2=6.63). No significant association was observed between TAGLN expression and other clinicopathologic characteristics, including gender, age and tumor size (p>0.05).ConclusionsOur study indicated that lentiviral shRNA targeting transgelin gene can inhibit the proliferation and tumor growth of A549cells in nude mice. The results suggest that knockdown transgelin gene could be an attractive strategy in the treatment of lung adenocarcinoma and justifes the use of letivirus in cancer gene therapy. In addition, the expression pattern of transgelin in lung adenocarcinoma was associated with TNM stage, lymph node status and differentiation grade. These results indicate that transgelin may be a useful biomarker for predicting lung adenocarcinoma prognosis and diagnosis.