Epigenetic Silencing Of Mir-137 Contributes To The Proliferation Of Multiple Myeloma By Targeting AURKA

MicroRNAs are non-coding small RNAs that modulate protein expression and are implicated in the pathogenesis of much kind of cancers. miR-137 was reported to act as a tumor suppressor in different cancers. In the present study, we describe the epigenetic regulation of miR-137 and its contribution in Multiple Myeloma (MM).

Real-time RT-PCR was used to screen the expression levels of miR-137 in MM cell lines and CD138⁺ cell sorted from MM patients, which confirmed the downregulation of miR-137 in MM cell lines and patients, and the expression of cell lines increasing treated with epigenetic drugs 5-aza-dC. The methylation status of miR-137 CpG island was determined by bisulfite pyrosequencing and methylation specific polymerase chain reaction (MSP). Methylation of the miR-137 CpG island was frequently observed in MM cell lines and patients but not in healthy donor and MGUS. Cck-8 assay showed transfection of miR-137 precursor in MM cells significantly inhibited cell proliferation and increased cell drug sensitivity. Importantly, Ectopic expression of miR-137 in MM cells inhibited phosphorylation of mitogen-activated protein kinase (MAPK/ERK). To further identify miR-137 targets, we used bioinformatics analysis and confirmed using a luciferase reporter assay. To validate AURKA as miR-137 target, we cloned the 3' UTR sequence of human AURKA into the luciferase-expressing vector psiCHECK. 293Tcells were transiently transfected with this construct in the presence of pre-miR-137 or a scrambled oligonucleotide acting as a negative control. As reported in luciferase plate reader, miR-137 significantly reduced luciferase activity compared with the scrambled control miRNA. This indicated that miR-137 binds to the 3'UTR of AURKA and impairs its mRNA translation. Furthermore, NCI-H929 cells were transfected with AURKA shRNA vector psiHIV-mH1-AURK and westernblot showed phosphorylation of ERK was also significantly decreased.

miR-137 was epigenetic Silenced and targeted AURKA expression to contribute to the proliferation through MAPK/ERK pathway in MM.

No relevant conflicts of interest to declare.