Expression And Function Of Liver Kinase B1 In Non Small Cell Lung Cancer

At present, lung cancer has been the malignant tumor disease which has the largest number of deaths in China and even in the whole world. More than 85%of these patients are attacked by non-small cell lung cancer(NSCLC), the most common subtypes of which are adenocarcinoma and squamous cell carcinoma, which whose symptoms are subtle, and most of the patients have been diagnosed in the middle and late stage. The surgery, the most commonly used and the most effective means of treatment, is not good for the efficacy and prognosis of patients with advanced stage. However, the surgical treatment cannot been performed when some patients were diagnosed. Other traditional treatments, like radiotherapy and chemotherapy have large side effects and the treatment effects are not good, so finding new treatments is necessary.In recent years, many breakthroughs have been made in gene therapy for tumor, in the meantime, some problems should be faced as well. By reason that deliver system of gene therapy in the human body can’t be specificly transfected into all tumor cells and it can’t be expressed with high efficiency in tumor, so the biological effects of therapeutic genes are difficult to be played. The reason like that result in the undesired anti-tumor ability of gene therapy. And the occurrence of cancer is a multi-step process that contains many genetic changes, so it is difficult to eliminate tumor alone by regulation of a single gene. Therefore, it has become a problem to be solved that the gene therapy strategy to seek tumor suppressor gene which can effectively inhibit lung cancer and the deliver system which is target oriented, safe and highly efficiently expresssed, expt.A number of recent studies have indicated that the liver kinase B1(LKB1) and phosphatase and tensin homolog deleted on chromosome ten(PTEN) is closely related to the occurrence and development of NSCLC,whose loss or downregulation of genes will induce NSCLC occur greatly change,then promote its pathogenesis.In this study, immunohistochemical is used to test the expression of LKB1 and PTEN in patients with NSCLC and analyze the potential relationship of these two tumor suppressor gene and NSCLC with clinical information. In addition, to detect the expression level of LKB1 and PTEN in four strains of NSCLC cell line, NA549 NCI-H23、NCI-H157、XWLC-05 and a SCLC cell line, NCI-H446, were detected through the immunocytochemistry、qPCR and western blot. Then reconstruct the recombinant adenovirus vector Ad-LKB1 through the AdMax system, to import the target gene into lung cancer cells and realize the over-expression of LKB1 in lung cancer cells, and preliminarily inquiry the effect of LKB1 on the proliferation and migration of lung cancer cells, especially non small cell lung cancer cells through the detection of proliferation activity and cell scratch repair by CCK-8 on in vitro cell.We found there are 35 cases are positive expression of PTEN (47.3%), and another52 cases are positive expression of LKB1 (70.3%) in the selected 74 patients with NSCLC. There was no significant difference in the expression level of the two genes with the gender, age, and pathological tissues of lung cancer.(P>0.05), but has significant difference with lymph node metastasis, surrounding tissue invasion, clinical stage, etc.(P<0.05). Combining expression levels of LKB1 and PTEN with malignant degree of patients we can found that, the higher expression level of LKB1 and PTEN was, the lower the degree of tumor malignancy was P<0.05.After the successful construction of recombinant adeno virus vector Ad-LKB 1, we found that over expression of LKB1 gene in lung cancer cells can inhibit the proliferation of lung cancer cells, and in XWLC-05 cells with the phenotype of LKB1-/PTEN- has the most significant inhibitory effect. But in NCI-H23 cells with a phenotype of LKB1+/PTEN+its inhibitory effect is relatively weak. In scratch repair experiment, compared with the control group cells infected with Ad-null, the over-expression of Ad-LKB1 after infection with LKB1 make all lung cancer cells have obvious cell migration inhibition phenomenon.The results of this study confirmed that the expression of LKB 1 and PTEN in NSCLC patients was down regulated, and we found that there may be a potential synergistic effect on the malignant progression of lung cancer. Through in vitro cell experiment, it was confirmed that the tumor suppressor gene LKB1 has a strong inhibitory effect on the proliferation and migration of lung cancer cells. It suggested that LKB1 and PTEN could be used as potential prognostic markers for lung cancer. LKB 1 has the potential to be the therapeutic targets, and provides a certain reference value to the new gene therapy. The specific molecular mechanism of LKB1 inhibiting the activity of lung cancer cells and its synergistic effect with PTEN in lung cancer remains to be further studied.