Zhong Ling, Jin Xin, Xu Zhuyu, Zeng Minghui, Chen Dongmei, He Yuan, Zhang Jianbo, Jiang Tao, Chen Jiao
Department of Clinical and Experimental Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China.
Department of Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, P.R. China.
Oncol Lett. 2020 Nov;20(5):263. doi: 10.3892/ol.2020.12126. Epub 2020 Sep 21.
The natural course of multiple myeloma (MM) varies greatly between patients. The Revised MM International Staging System (R-ISS) identifies high-risk patients, but it is unsuitable for assessing minimal residual disease (MRD). Furthermore, the focal location of myeloma cells and clonal evolution often produce false negative results in flow cytometry. Extracellular microRNA (miRNA/miR) expression levels are stable in bodily fluids, and are retrievable and measurable from fresh or archived serum or plasma samples. Therefore, the present study aimed to investigate the clinical utility of circulating miRNA levels in patients with MM, particularly miR-451a, which is commonly downregulated in MM, and whether it could predict the prognosis and relapse of patients with MM. In total, 66 patients with MM, stratified using the R-ISS criteria, were recruited, while 10 healthy subjects (transplantation donors) were enrolled as controls. Reverse transcription-quantitative PCR was used to evaluate miR-451a expression in bone marrow (BM) and in the circulation. IL-6 levels were measured using ELISA, while western blotting was conducted to analyze the protein expression levels of the IL-6 receptor (IL-6R). During follow-up, MRD was assessed via multiparameter flow cytometry (MFC). miR-451a was identified to target IL-6R using a dual-luciferase reporter assay. Circulating miR-451a levels were low in patients with MM, and was found to be 0.39 times that of the control group (U=4.00; P<0.001). Among the 66 patients with MM, the median level of miR-451a was 0.73 and 0.41 times that of the control group in R-ISS stage I MM (15 patients) and R-ISS stage II stage (17 patients), respectively; patients with R-ISS stage III MM (34 patients) had the lowest level, at 0.24 times the value of the control group. Circulating miR-451a levels had a strong positive correlation with miR-451a levels in BM, but negatively correlated with IL-6 and IL-6R levels. After two courses of consolidation chemotherapy, 19 patients achieved complete remission, 10 of whom presented steady circulating miR-451a levels during follow-up; the other nine patients had an abrupt decrease in circulating miR-451a levels. The turning points in the trend appeared 4-8 weeks before positive results were obtained via MFC, and 4-16 weeks before clinical relapse. Moreover, miR-451a overexpression notably downregulated the expression of the IL-6R mRNA and protein. Collectively, circulating miR-451a levels potentially represent a novel biomarker to monitor MRD and predict relapse.
多发性骨髓瘤（MM）患者的自然病程差异很大。修订后的MM国际分期系统（R-ISS）可识别高危患者，但不适用于评估微小残留病（MRD）。此外，骨髓瘤细胞的局灶性定位和克隆进化常导致流式细胞术出现假阴性结果。细胞外微小RNA（miRNA/miR）表达水平在体液中稳定，可从新鲜或存档的血清或血浆样本中获取并测量。因此，本研究旨在探讨循环miRNA水平在MM患者中的临床应用价值，特别是在MM中通常下调的miR-451a，以及它是否可以预测MM患者的预后和复发情况。总共招募了66例根据R-ISS标准分层的MM患者，同时纳入10名健康受试者（移植供体）作为对照。采用逆转录定量PCR评估骨髓（BM）和循环中miR-451a的表达。使用酶联免疫吸附测定（ELISA）测量白细胞介素-6（IL-6）水平，同时进行蛋白质印迹分析IL-6受体（IL-6R）的蛋白表达水平。在随访期间，通过多参数流式细胞术（MFC）评估MRD。使用双荧光素酶报告基因测定法确定miR-451a靶向IL-6R。MM患者的循环miR-451a水平较低，发现其为对照组的0.39倍（U = 4.00；P < 0.001）。在66例MM患者中，R-ISS I期MM（15例）和R-ISS II期MM（17例）患者的miR-451a中位数水平分别为对照组的0.73倍和0.41倍；R-ISS III期MM（34例）患者的水平最低，为对照组值的0.24倍。循环miR-451a水平与BM中miR-451a水平呈强正相关，但与IL-6和IL-6R水平呈负相关。经过两个疗程的巩固化疗后，19例患者达到完全缓解，其中10例在随访期间循环miR-451a水平稳定；其他9例患者的循环miR-451a水平突然下降。趋势转折点出现在通过MFC获得阳性结果前4 - 8周，以及临床复发前4 - 16周。此外，miR-451a过表达显著下调IL-6R mRNA和蛋白的表达。总体而言，循环miR-451a水平可能代表一种监测MRD和预测复发的新型生物标志物。
