miR-152-mediated MKK7 downregulation is attenuated by MYCNOS in ovarian adenocarcinoma.

MYCN opposite strand (MYCNOS) acts as an oncogenic long non-coding RNA in liver cancer. However, its role in other cancer types is unknown. The aim of the present study was to investigate the function of MYCNOS in ovarian adenocarcinoma (OA). MYCNOS expression in OA was determined using reverse transcription-quantitative PCR (RT-qPCR), and its prognostic value for OA was evaluated in a 5-year follow-up study. The predicted interaction between MYCNOS and microRNA (miR)-152 was confirmed using a dual luciferase reporter assay. The association between MYCNOS and miR-152 was also analyzed in overexpression experiments. The effects of MYCNOS and miR-152 on mitogen-activated protein kinase kinase 7 (MKK7) expression were explored using RT-qPCR and western blotting. Cell proliferation was analyzed using a Cell Counting Kit-8 assay. MYCNOS expression was found to be upregulated in OA and predicted poor survival. In addition, MYCNOS was predicted to interact with miR-152, and a dual luciferase assay confirmed this interaction. However, MYCNOS and miR-152 overexpression did not affect their mutual expression levels. MYCNOS overexpression upregulated MKK7, a target of miR-152. Cell proliferation increased following simultaneous MYCNOS and MKK7 overexpression, but was reduced following miR-152 overexpression. Moreover, MYCNOS overexpression attenuated the effects of miR-152 overexpression. In conclusion, MYCNOS may act by sponging miR-152 to upregulate MKK7 expression in OA, thereby promoting cell proliferation.