LncRNA GASL1 inhibits tumor growth of non-small cell lung cancer by inactivating TGF-ß pathway.

ABSTRACT

OBJECTIVE: Growth-Arrest Associated lncRNA 1 (GASL1) is a newly discovered lncRNA that plays a role as tumor suppressor gene in liver cancer, while its involvement in other malignancies is unknown. We aimed to investigate the involvement of GASL1 in non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Tumor tissue and adjacent healthy tissues were collected from 98 patients with NSCLC, and blood samples were collected from both NSCLC patients and healthy controls to detect GASL1 expression. All patients were followed up for 5 years and the diagnostic and prognostic values of GASL1 for NSCLC were evaluated by ROC curve analysis and survival curve analysis, respectively. Correlations between serum levels of GASL1 and clinicopathological data of NSCLC patients were analyzed by Chi-square test. GASL1 overexpression and knockdown cancer cell lines were constructed and the effects on transforming growth factor ß1 (TGF-ß1) expression and cell proliferation were explored by Western blot and CCK-8 assay, respectively. RESULTS: We found that lncRNA GASL1 expression was significantly downregulated in tumor tissues than in adjacent healthy tissues. Serum level of GASL1 was also lower in cancer patients than in healthy controls. Serum GASL1 is a sensitive diagnostic biomarker for NSCLC, and low expression level of GASL1 indicated short postoperative survival time. Overexpression of GASL1 upregulated, while GASL1 knockdown downregulated TGF-ß1 expression. GASL1 overexpression inhibited, and GASL1 knockdown promoted cancer cell proliferation. CONCLUSIONS: We found that lncRNA GASL1 may inhibit tumor growth of NSCLC by downregulating TGF-ß1.