title: miR-125b, a target of CDX2, regulates cell differentiation through repression of the core binding factor in hematopoietic malignancies.
abstract: MicroRNA-125b (miR-125b), a small noncoding RNA molecule, has been found to be deregulated and functions as an oncogene in many cancers including hematopoietic malignancies. However, the mechanisms accounting for miR-125b dysregulation remain to be elucidated. The present study aims to identify the factors that might contribute to up-regulation of miR-125b in human hematopoietic malignancies and its downstream targets for lineage-specific differentiation. We at first reported that CDX2, a homeobox transcription factor, binds to promoter regions of the miR-125b gene and activates transcriptional regulation of miR-125b in malignant myeloid cells. We further revealed that increasing levels of CDX2 in malignant myeloid cells activate miR-125b expression, which in turn inhibits core binding factor β (CBFβ) translation, thereby counteracting myeloid cell differentiation, at least for granulocytic lineage, and promoting leukemogenesis. Interestingly, we found that this novel pathway including CDX2, miR-125b, and CBFβ was mediated by undergoing all-trans-retinoic acid induction. Once differentiation ensues with all-trans-retinoic acid treatment, CDX2 activity decreases, leading to a reduction in miR-125b transcription and up-regulation of CBFβ in myeloid cells and in patients. The study provides a new mechanism that contributes to hematopoietic malignancies, which could involve deregulation of miR-125b and its up- and downstream factors. As altered expression of miRNAs has been reported in a wide range of malignancies, delineating the underlying molecular mechanisms of aberrant miRNA expression and characterizing the upstream and downstream factors will help to understand important steps in the pathogenesis of these afflictions.
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
authors: Kang-Yu
authors: KY
authors: Lin
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
authors: Xing-Ju
authors: XJ
authors: Zhang
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
authors: Dan-Dan
authors: DD
authors: Feng
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
authors: Hua
authors: H
authors: Zhang
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
authors: Cheng-Wu
authors: CW
authors: Zeng
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
authors: Bo-Wei
authors: BW
authors: Han
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
authors: Ai-Dong
authors: AD
authors: Zhou
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China.
authors: Liang-Hu
authors: LH
authors: Qu
authors: Second Affiliated Hospital, Sun Yat-sen University, Guangzhou 510275, China. Electronic address: luoxul64@yahoo.com.
authors: Ling
authors: L
authors: Xu
authors: Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, China. Electronic address: lsscyq@mail.sysu.edu.cn.
authors: Yue-Qin
authors: YQ
authors: Chen
mesh_terms: D000071616:CDX2 Transcription Factor; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D050658:Core Binding Factor beta Subunit / Q000378:metabolism*; D015973:Gene Expression Regulation, Leukemic; D018922:HL-60 Cells; D019337:Hematologic Neoplasms / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D035683:MicroRNAs / Q000378:metabolism*; D008954:Models, Biological; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: C493692:CBFB protein, human; D000071616:CDX2 Transcription Factor; C491270:CDX2 protein, human; D050658:Core Binding Factor beta Subunit; D018398:Homeodomain Proteins; C531888:MIRN125 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger