Li Haiying, Xing Chongyun, Zhou Bin, Ye Haige, Feng Jianhua, Wu Jianbo, Gao Shenmeng
Laboratory of Internal Medicine, First Affiliated Hospital of Wenzhou Medical University, Nanbaixiang, Ouhai District, Wenzhou, China.
Department of Hematology, First Affiliated Hospital of Wenzhou Medical University, Nanbaixiang, Ouhai District, Wenzhou, China.
Exp Hematol. 2018 May;61:59-68.e5. doi: 10.1016/j.exphem.2018.02.001. Epub 2018 Feb 13.
The aberrant overexpression of Wilms tumor-1 (WT1) in acute myeloid leukemia (AML) plays an important role in blast cell survival by enhancing proliferation and inhibiting apoptosis. However, the mechanism underlying the overexpression of WT1 remains unclear. Here, we identified miR-193a (miR-193a-5p) and miR-600 targeting and degrading WT1. MiR-193a and miR-600 synergistically reduced WT1 expression and suppressed the activity of a luciferase reporter by binding coding sequence and the 3'-untranslated region of WT1 mRNA, respectively. Furthermore, the expression of miR-193a and miR-600 was decreased in AML patients compared with normal controls. DNA hypermethylation in pre-miR-193a promoter, but not pre-miR-600 promoter, caused the downregulation of miR-193a. Most intriguingly, ectopic expression of WT1 inhibited miR-600 expression, in turn, by binding the putative pre-miR-600 promoter, leading to the downregulation of miR-600 in AML blasts. Ectopic expression of miR-193a and miR-600 synergistically inhibited cell proliferation, induced apoptosis, and decreased colony formation in leukemia cells. Finally, overexpression of miR-193a and miR-600 decreased the growth of K562-inoculated tumor xenografts and extended survival time in THP1-transplanted leukemia mice. In conclusion, these data reveal an important role of miRNAs-WT1 circuitry in leukemia cells and the therapeutic promise of restoring miR-193a and miR-600 expression in AML patients.
威尔姆斯瘤基因1（WT1）在急性髓系白血病（AML）中的异常过表达通过增强增殖和抑制凋亡在原始细胞存活中发挥重要作用。然而，WT1过表达的潜在机制仍不清楚。在此，我们鉴定出靶向并降解WT1的miR-193a（miR-193a-5p）和miR-600。miR-193a和miR-600分别通过结合WT1 mRNA的编码序列和3'非翻译区，协同降低WT1表达并抑制荧光素酶报告基因的活性。此外，与正常对照相比，AML患者中miR-193a和miR-600的表达降低。pre-miR-193a启动子而非pre-miR-600启动子的DNA高甲基化导致miR-193a下调。最有趣的是，WT1的异位表达通过结合假定的pre-miR-600启动子反过来抑制miR-600表达，导致AML原始细胞中miR-600下调。miR-193a和miR-600的异位表达协同抑制白血病细胞的增殖、诱导凋亡并减少集落形成。最后，miR-193a和miR-600的过表达降低了接种K562的肿瘤异种移植物的生长，并延长了THP1移植的白血病小鼠的存活时间。总之，这些数据揭示了miRNAs-WT1信号通路在白血病细胞中的重要作用以及恢复AML患者中miR-193a和miR-600表达的治疗前景。
