The Role and Antagonistic Effects of miR-16-5p in the Regulation of ADP-Ribosylation Factor-Like Tumor Suppressor Gene 1 in Lung Cancer Cells.

OBJECTIVE: ADP-ribosylation factor-like tumor suppressor gene 1 is a member of the Ras superfamily of small guanosine triphosphatases that are known to be involved in multiple regulatory pathways in the multistage development of human cancers. Also, ADP-ribosylation factor-like tumor suppressor gene 1 expression levels have been reported to be dramatically lower in both cancer cell lines and tumor tissues compared to controls. Accordingly, defects in the regulation of the ADP-ribosylation factor-like tumor suppressor gene 1 gene seems have key tumor suppressive effects in the formation and development of human cancers including lung cancer. Moreover, microRNAs regulating the expression of ADP-ribosylation factor-like tumor suppressor gene 1 have not been described previously. Accordingly, the present study aimed to reveal the influence of miR-16-5p on the regulation of ADP-ribosylation factor-like tumor suppressor gene 1 gene.

MATERIALS AND METHODS: A549 lung adenocarcinoma cells were used. For the overexpression and silencing experiments of miR-16-5p synthetic microRNA mimics and inhibitors were used, respectively. Gene expression analyses were achieved with the help of quantitative real-time polymerase chain reaction.

RESULTS: MiR-16-5p was identified to be predictive target of ADP-ribosylation factor-like tumor suppressor gene 1 and directly targets the expression of ADP-ribosylation factor-like tumor suppressor gene 1 as revealed by the overexpression and silencing experiments. Specifically, it was found that miR-16-5p-overexpressed A549 cells showed a decrease in ADP-ribosylation factor-like tumor suppressor gene 1 gene expression, whereas miR16-5p-suppressed cells showed an increase in expression. These findings possibly suggest that miR-16-5p is the direct regulatory microRNA that posttranscriptionally regulates the expression of ADP-ribosylation factor-like tumor suppressor gene 1.

CONCLUSION: Collectively, miR-16-5p seems to be a key regulatory molecule involved in the posttranscriptional regulation of the ADP-ribosylation factor-like tumor suppressor gene 1, and it might be responsible for the downregulation of this gene in lung cancer.