Magnolol suppressed cell migration and invasion and induced cell apoptosis via inhibition of the NF-κB signaling pathway by upregulating microRNA-129 in multiple myeloma.

Multiple myeloma (MM) is incurable cancer in the blood system. Magnolol is an effective component against various cancers. This study tried to investigate the effect and mechanism of magnolol on MM via regulating miR-129. Human normal plasma cells (nPCs) and MM cells U266 and LP1 were used in this study, accompanied by treatment of magnolol. The miR-129 inhibitor was transfected into U266 and LP1 cells during experiments. Cell viability was detected by Cell Counting Kit-8 assay. Cell migration and invasion were tested by wound healing assay and Transwell assay. And Annexin-V-FITC/PI assay was utilized to assess cell apoptosis. miR-129, miR-1271-5p, miR-342-3p, and miR-124-3p expressions were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and western blot was adopted to evaluate Cyclin D1, matrix metalloprotein (MMP)-7, MMP-9, phosphorylation (p)-IκBα, p-p65, and p65 protein levels. In U266 and LP1 cells, with magnolol concentration increasing, cell viability, migration, and invasion rates, Cyclin D1, MMP-7, and MMP-9 expressions decreased, while cell apoptosis rose. And magnolol increased the miR-129 expression in MM cells. Besides, miR-129 inhibitor antagonized the above-mentioned effect of magnolol and partly offset the magnolol-induced decrease of p-IκBα and p-p65 expression, as well as the ratio of p-p65 to p65 in U266 and LP1 cells. Magnolol suppressed cell migration and invasion and induced cell apoptosis via inhibiting NF-κB pathway activation, by upregulating miR-129 in MM.