[XAF1 inhibits cell proliferation and induces apoptosis in human lung adenocarcinoma cell line A549 in vitro].

BACKGROUND AND OBJECTIVE: XAF1 is a factor necessary to inhibit tumor cell growth. Low XAF1 expression is associated with various tumor cells. The aim of this study is to investigate the effect and the mechanism of adenovirus vector Ad5/F35 mediated X-linked inhibitor of apoptosis protein associated factor-1 (XAF1) on the inhibition of cell proliferation and the induction of apoptosis of human lung adenocarcinoma cell A549.

METHODS: Recombinant virus Ad5/F35-XAF1 and controlled virus Ad5/F35-NULL exhibited different multiplicities of infection (MOI) at the same time. mRNA and protein expressions of XAF1 were determined by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot, respectively. Cell proliferation was observed by methyl thiazolyl tetrazolium (MTT) assay, and cell apoptosis was analyzed by FACS with Annexin V-FITC/PI double staining. The expressions of apoptosis-associated proteins, such as PARP, Caspase-3, and Caspase-8, were also determined by Western blot.

RESULTS: mRNA and protein expressions of XAF1 were significantly increased in human lung adenocarcinoma cell A549 after this cell was transfected with Ad5/F35-XAF1 for 48 h; these expressions were higher than those of the controlled group Ad5/F35-NULL. Cell proliferation was inhibited and apoptosis was induced in a dose-dependent manner in the Ad5/F35-XAF1 group. After Ad5/F35-XAF1 transfection was performed, the cleavage of apoptosis-associated proteins, such as PARP, Caspase-3, and Caspase-8, was activated.

CONCLUSIONS: Restored XAF1 expression inhibits cell proliferation and induces cell apoptosis in human lung adenocarcinoma cell line A549. Furthermore, XAF1 may activate associated apoptotic signaling pathways in A549 cell line.