miR-4326 promotes lung cancer cell proliferation through targeting tumor suppressor APC2.

microRNAs have been reported to play vital role in lung cancer proliferation and metastasis; the role of miR-4326 in tumor progression has not been studied. Here, we studied the effect of miR-4326 on lung cancer cell proliferation; we found that miR-4326 was significantly upregulated in lung cancer tissues determined using TCGA dataset and clinical specimens, meanwhile it was also upregulated in lung cancer cells. Overexpression of miR-4326 promoted lung cancer cell proliferation analyzed by MTT, soft agar growth, and BrdU incorporation assay, while miR-4326 knockdown suppressed lung cancer cell proliferation. We found miR-4326 targets tumor suppressor adenomatous polyposis coli 2 (APC2), which is a negative regulator of Wnt pathway, by binding to the 3'UTR of APC2. Wnt pathway could increase Cyclin D1 and c-MYC expression, we also found that miR-4326 could increase their expression, suggesting that APC2 was the target of miR-4326. Moreover, double knockdown of APC2 and miR-4326 promoted lung cancer cell proliferation, confirming that miR-4326 promoted lung cancer cell proliferation by inhibiting APC2.