MicroRNA (
miRNA/miR) dysfunction is a hallmark of
lung cancer, and results in the dysregulation of
tumor suppressors and oncogenes during
lung cancer progression. Selection of the 5p and 3p arms of
miRNA is a mechanism that improves the modulation of
miRNA biological functions and complicates the regulatory network in human types of
cancer. However, the involvement of arm selection preference of
miRNA in
lung cancer remains unclear. In the present study, changes in
miRNA arm selection preference were comprehensively identified in
lung cancer and corresponding adjacent normal tissues by analyzing The
Cancer Genome Atlas. Arm selection was revealed to be consistent in the majority of
miRNAs in
lung cancer. Only a few
miRNAs had significantly altered arm selection preference in
lung cancer. Among these, the biological functions of the individual arms of miR-324 were investigated further. The data revealed that miR-324-5p and -3p were significantly overexpressed in
lung cancer cells. Ectopic expression of miR-324-5p significantly promoted cell proliferation and invasion in
lung cancer cells, while miR-324-3p overexpression significantly increased cell proliferation but did not alter the invasion of
lung cancer cells. In conclusion, the arm selection preference of
miRNA may be an additional mechanism through which biological functions are modulated. The results of the present study provide a novel insight into the underlying mechanisms of
lung cancer and may direct research into future
therapies.