miR-100-5p is upregulated in multiple myeloma and involves in the pathogenesis of multiple myeloma through targeting MTMR3

MicroRNA (miRNA) is a kind of highly conserved single-stranded small endogenous non-coding RNA associated with multiple diseases, particularly cancer. The miRNAs expression profile in multiple myeloma (MM) has been barely elucidated. The miRNAs expression profiles in bone marrow plasma cells of 5 MM individuals and 5 iron-deficiency anemia volunteers were analyzed using RNA-sequencing. Quantitative polymerase chain reaction (QPCR) was performed to validate the expression of selected miR-100-5p. The biological function of selected miRNA was predicated by bioinformatics analysis. Finally, the function of miR-100-5p and its target on MM cells were evaluated. MiRNA-sequencing showed that miR-100-5p was obviously upregulated in MM patients, which was further validated in an expanded cohort. Receiver operating characteristic curve analysis characterized miR-100-5p as a valuable biomarker of MM. Bioinformatics analysis predicted that miR-100-5p is targeted to CLDN11, ICMT, MTMR3, RASGRP3, and SMARCA5, and their low expression are associated with poor prognosis of MM patients. Kyoto encyclopedia of genes and genomes analysis suggested that the major interacting proteins of these five targets are mainly enriched in inositol phosphate metabolism and phosphatidylinositol signaling system pathway. <i>In vitro</i> study showed that miR-100-5p inhibition promoted the expression of these targets, especially MTMR3. In addition, miR-100-5p inhibition declined living number and metastasis, whereas promoted apoptosis of RPMI 8226 and U266 MM cells. The function of miR-100-5p inhibition was weakened by MTMR3 inhibition. These results indicates that miR-100-5p is a promising biomarker for MM, and that it may involve in the pathogenesis of MM by targeting MTMR3.

微小RNA（MicroRNA，miRNA）是一类高度保守的单链内源性非编码RNA，与多种疾病尤其是癌症密切相关。目前针对多发性骨髓瘤（multiple myeloma，MM）的miRNA表达谱研究尚少。本研究采用RNA测序（RNA-sequencing）分析了5名多发性骨髓瘤患者与5名缺铁性贫血志愿者的骨髓浆细胞miRNA表达谱；通过定量聚合酶链反应（Quantitative polymerase chain reaction，QPCR）验证了筛选得到的miR-100-5p的表达水平；借助生物信息学分析预测了所筛选miRNA的生物学功能，并最终评估了miR-100-5p及其靶基因在多发性骨髓瘤细胞中的功能。miRNA测序结果显示，miR-100-5p在多发性骨髓瘤患者中显著上调，该结果在扩大样本队列中得到进一步验证。受试者工作特征曲线（Receiver operating characteristic curve，ROC曲线）分析表明，miR-100-5p可作为多发性骨髓瘤的潜在生物标志物。生物信息学分析预测，miR-100-5p的靶基因为CLDN11、ICMT、MTMR3、RASGRP3及SMARCA5，且这些靶基因的低表达与多发性骨髓瘤患者的不良预后显著相关。京都基因与基因组百科全书（Kyoto encyclopedia of genes and genomes，KEGG）富集分析显示，这5个靶基因的主要互作蛋白主要富集于肌醇磷酸代谢与磷脂酰肌醇信号通路中。体外实验结果显示，抑制miR-100-5p的表达可上调这些靶基因的表达，其中以MTMR3最为显著。此外，抑制miR-100-5p可降低RPMI 8226与U266多发性骨髓瘤细胞的存活数量与迁移侵袭能力，同时促进细胞凋亡；而抑制MTMR3的表达则会削弱miR-100-5p抑制所介导的生物学效应。上述结果表明，miR-100-5p有望成为多发性骨髓瘤的新型生物标志物，且其可能通过靶向调控MTMR3参与多发性骨髓瘤的发病过程。