Su R, Lin H-S, Zhang X-H, Yin X-L, Ning H-M, Liu B, Zhai P-F, Gong J-N, Shen C, Song L, Chen J, Wang F, Zhao H-L, Ma Y-N, Yu J, Zhang J-W
Key State Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Department of Hematology, the 303 Hospital, Nanning, Guangxi, China.
Oncogene. 2015 Jun;34(25):3226-39. doi: 10.1038/onc.2014.274. Epub 2014 Sep 1.
MicroRNAs have been shown to play an important role in normal hematopoisis and leukemogenesis. Here, we report function and mechanisms of miR-181 family in myeloid differentiation and acute myeloid leukemia (AML). The aberrant overexpression of all the miR-181 family members (miR-181a/b/c/d) was detected in French-American-British M1, M2 and M3 subtypes of adult AML patients. By conducting gain- and loss-of-function experiments, we demonstrated that miR-181a inhibits granulocytic and macrophage-like differentiation of HL-60 cells and CD34+ hematopoietic stem/progenitor cells (HSPCs) by directly targeting and downregulating the expression of PRKCD (which then affected the PRKCD-P38-C/EBPα pathway), CTDSPL (which then affected the phosphorylation of retinoblastoma protein) and CAMKK1. The three genes were also demonstrated to be the targets of miR-181b, miR-181c and miR-181d, respectively. Significantly decreases in the expression levels of the target proteins were detected in AML patients. Inhibition of the expression of miR-181 family members owing to Lenti-miRZip-181a infection in bone marrow blasts of AML patients increased target protein expression levels and partially reversed myeloid differentiation blockage. In the mice implanted with AML CD34+ HSPCs, expression inhibition of the miR-181 family by Lenti-miRZip-181a injection improved myeloid differentiation, inhibited engraftment and infiltration of the leukemic CD34+ cells into the bone marrow and spleen, and released leukemic symptoms. In conclusion, our findings revealed new mechanism of miR-181 family in normal hematopoiesis and AML development, and suggested that expression inhibition of the miR-181 family could provide a new strategy for AML therapy.
微小RNA已被证明在正常造血和白血病发生过程中发挥重要作用。在此，我们报告miR-181家族在髓系分化和急性髓系白血病（AML）中的功能及机制。在成年AML患者的法美英协作组（FAB）M1、M2和M3亚型中检测到所有miR-181家族成员（miR-181a/b/c/d）异常过表达。通过进行功能获得和功能缺失实验，我们证明miR-181a通过直接靶向并下调PRKCD（进而影响PRKCD-P38-C/EBPα通路）、CTDSPL（进而影响视网膜母细胞瘤蛋白的磷酸化）和CAMKK1的表达，抑制HL-60细胞以及CD34+造血干/祖细胞（HSPCs）向粒细胞和巨噬细胞样分化。这三个基因也分别被证明是miR-181b、miR-181c和miR-181d的靶标。在AML患者中检测到靶蛋白表达水平显著降低。由于慢病毒介导的miRZip-181a感染导致AML患者骨髓母细胞中miR-181家族成员表达受到抑制，从而增加了靶蛋白表达水平，并部分逆转了髓系分化阻滞。在植入AML CD34+ HSPCs的小鼠中，通过注射慢病毒介导的miRZip-181a抑制miR-181家族的表达，改善了髓系分化，抑制了白血病CD34+细胞在骨髓和脾脏中的植入和浸润，并缓解了白血病症状。总之，我们的研究结果揭示了miR-181家族在正常造血和AML发生发展中的新机制，并表明抑制miR-181家族的表达可为AML治疗提供新策略。
