A novel miR-375-HOXB3-CDCA3/DNMT3B regulatory circuitry contributes to leukemogenesis in acute myeloid leukemia

• Published in: BMC cancer Vol. 18; no. 1; pp. 182 - 17
• Main Authors: Bi, Laixi, Zhou, Bin, Li, Haiying, He, Licai, Wang, Chunjing, Wang, Zhonggai, Zhu, Liqing, Chen, Mengqian, Gao, Shenmeng
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 13.02.2018; BioMed Central; BMC
• Subjects: 3' Untranslated Regions - genetics; Acute Disease; Acute myelocytic leukemia; Adult; AML; Animals; Carcinogenesis - genetics; Carcinogenesis - metabolism; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cell Line, Tumor; Development and progression; DNA (Cytosine-5-)-Methyltransferases - genetics; DNA (Cytosine-5-)-Methyltransferases - metabolism; DNA hypermethylation; DNA Methyltransferase 3B; DNMT3B; Female; Gene expression; Gene Expression Regulation, Leukemic; Genetic aspects; HL-60 Cells; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; HOXB3; Humans; K562 Cells; Kaplan-Meier Estimate; Leukemia, Myeloid - genetics; Leukemia, Myeloid - metabolism; Leukemia, Myeloid - pathology; Male; Mice, Inbred NOD; Mice, Knockout; Mice, Nude; Mice, SCID; MicroRNA; MicroRNAs - genetics; Middle Aged; miR-375; Myeloid leukemia; Transplantation, Heterologous; Young Adult; AML; DNMT3B; DNA hypermethylation; HOXB3; miR-375
• ISSN: 1471-2407; 1471-2407
• DOI: 10.1186/s12885-018-4097-z

Acute myeloid leukemia (AML) is a heterogeneous group of hematopoietic malignancies due to sophisticated genetic mutations and epigenetic dysregulation. MicroRNAs (miRNAs), a class of small non-coding RNAs, are important regulators of gene expression in all biological processes, including leukemogenesis. Recently, miR-375 has been reported to be a suppressive miRNA in multiple types of cancers, but its underlying anti-leukemia activity in AML is largely unknown. Quantitative reverse transcriptase PCR (qRT-PCR) was used to measure the expression of miR-375 and HOXB3 in leukemic cells and normal controls. Targets of miR-375 were confirmed by western blot and luciferase assay. Phenotypic effects of miR-375 overexpression and HOXB3 knockdown were assessed using viability (trypan blue exclusion assay), colony formation/replating, as well as tumor xenograft assays in vivo. The expression of miR-375 was substantially decreased in leukemic cell lines and primary AML blasts compared with normal controls, because DNA hypermethylation of precursor-miR-375 (pre-miR-375) promoter was discovered in leukemic cells but not in normal controls. Lower expression of miR-375 predicted poor outcome in AML patients. Furthermore, forced expression of miR-375 not only decreased proliferation and colony formation in leukemic cells but also reduced xenograft tumor size and prolonged the survival time in a leukemia xenograft mouse model. Mechanistically, overexpression of miR-375 reduced HOXB3 expression and repressed the activity of a luciferase reporter through binding 3'-untranslated regions (3'-UTR) of HOXB3 mRNA. Overexpression of HOXB3 partially blocked miR-375-induced arrest of proliferation and reduction of colony number, suggesting that HOXB3 plays an important role in miR-375-induced anti-leukemia activity. Knockdown of HOXB3 by short hairpin RNAs reduced the expression of cell division cycle associated 3 (CDCA3), which decreased cell proliferation. Furthermore, HOXB3 induced DNA methyltransferase 3B (DNMT3B) expression to bind in the pre-miR-375 promoter and enhanced DNA hypermethylation of pre-miR-375, leading to the lower expression of miR-375. Collectively, we have identified a miR-375-HOXB3-CDCA3/DNMT3B regulatory circuitry which contributes to leukemogenesis and suggests a therapeutic strategy of restoring miR-375 expression in AML.