[Lncrna CRNDE Promotes Proliferation and Inhibits Apoptosis of U937 Cells by Downregulating Mir-136-5p and Upregulating MCM5].

Objective To investigate the effect of lncRNA CRNDE on proliferation, apoptosis, and cell cycle of U937 cells and its mechanism. Methods The expression level of CRNDE in bone marrow cells of AML patients was analyzed by GEPIA database; the mRNA expression levels of miR-136-5p, CRNDE, and minichromosome maintenance 5(MCM5) in AML cell lines were detected by quantitative real-time PCR (qRT-PCR). The lentiviral vector with CRNDE knocked down was constructed and transfected into U937 cells which were randomized into CRNDE knockdown group (sh-CRNDE group) and negative control group (sh-NC group); miR-136-5p mimic and miR-136-5p inhibitor were transfected respectively to overexpress and knock down miR-136-5p in U937 cells which were randomized into miR-136-5p-mimic group, NC-mimic group, miR-136-5p-inhibitor group, and NC-inhibitor group. The effect of CRNDE and miR-136-5p on proliferation was detected by CCK-8 assay and cell counting assay, and the effect of them on cell cycle and apoptosis was detected by flow cytometry. The mRNA expressions of miR-136-5p, CRNDE, and MCM5 were detected by qRT-PCR, and the protein expressions of MCM5, Bcl2, cyclin D1, and cyclin A2 were detected by Western blotting. Results CRNDE was highly expressed in the bone marrow and cell lines of AML patients. Knockdown of CRNDE upregulated miR-136-5p, inhibited the MCM5 mRNA and protein expressions and the cell proliferation, promoted the cell apoptosis, and blocked the cell cycle in G1 phase. Overexpression of miR-136-5p also inhibited the expression of MCM5 at both mRNA and protein levels, while knockdown of miR-136-5p reversed those effects. Conclusion CRNDE promotes the proliferation and inhibits the apoptosis of U937 cells by downregulating miR-136-5p and upregulating MCM5.