[Analysis of suppressive role of RASSF1A gene at 3p21.3 in lung cancer cell line A549]

Abstract

Objective: Loss of heterozygosity (LOH) at 3p21.3 is a common and early event in the development of lung cancer, implying the presence of tumor suppressor genes (TSGs) that may be involved in the pathogenesis of lung cancer. RASSF1A gene, located at this region, containing the Ras-associated domain, has been considered as a candidate tumor suppressor gene because of high frequency of loss of expression and aberrant promoter hypermethylation in most NSCLCs and SCLCs. This study was designed to transfer the expression vector containing RASSF1A to NSCLC cell line A549 to analyze the effect of this gene's exogenous expression.

Methods: Transfer the pcDNA3.1 and pcDNA3.1-RASSF1A into A549 cells by lipofectamine 2000 respectively, the apoptosis and the changes of cell cycle of transient-transfected cells were analyses by flow cytometry (FCM), cellular proliferation of the stable-transfected was examined by MTT assay, cell growth curve and colony formation assay. Inhibition of lung metastasis in nude mice of RASSF1A exogenous expression was also investigated.

Results: The progression of the cell cycle was arrested in G1-phase remarkably induced by RASSF1A (P < 0.001); the cell viability, growing speed and colony formation ability were decreased obviously by exogenous expression of RASSF1A (P < 0.01). The lung metastasis in nude mouse was also significantly inhibited (P < 0.01).

Conclusion: The experimental results show that RASSF1A plays an important roles in origination, progression and metastasis of lung cancer.