title: Role of the Wilms' tumor 1 gene in the aberrant biological behavior of leukemic cells and the related mechanisms.
abstract: The Wilms' tumor 1 (WT1) gene is one of the regulating factors in cell proliferation and development. It is a double-functional gene: an oncogene and a tumor suppressor. This gene was found to be highly expressed in many leukemic cell lines and in patients with acute myeloid leukemia. In the present study, we demonstrated that the WT1 gene was commonly expressed in leukemic cell lines apart from U937 cells. The K562 cell line which expresses WT1 at a high level (mRNA and protein) was used in the entire experiment. By MTT and colony formation assays, we found that curcumin, an inhibitor of the WT1 protein, inhibited cell proliferation and clonogenicity in a time- and dose-dependent manner. It also caused cell cycle arrest at the G2/M phase. We then designed specific short hairpin RNAs (shRNAs) which could downregulate WT1 by 70-80% at the mRNA and protein levels. Reduction in the WT1 levels attenuated the proliferative ability and clonogenicity. Cell cycle progression analysis indicated that the proportion of cells in the G0/G1 phase increased while the proportion in the S phase decreased distinctively. ChIP-DNA selection and ligation (DSL) experiment identified a cohort of genes whose promoters are targeted by WT1. These genes were classified into different cellular signaling pathways using MAS software and included the Wnt/β-catenin pathway, MAPK signaling pathway, apoptosis pathway, and the cell cycle. We focused on the Wnt/β-catenin signaling pathway, and compared expression of several genes in the K562 cells transfected with the control shRNA and WT1-specific shRNA. β-catenin, an important gene in the Wnt canonical pathway, was downregulated after WT1 RNAi. Target genes of β-catenin which participate in cell proliferation and cell cycle regulation, such as CCND1 and MYC, were also significantly downregulated. Collectively, these data suggest that WT1 functions as an oncogene in leukemia cells, and one important mechanism is regulation of the Wnt/β-catenin pathway.
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Jiying
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Yujiao
authors.initials: Y
authors.lastname: Jia
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Huai
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Kan
authors.initials: K
authors.lastname: He
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Pei
authors.initials: P
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Xing
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Rao
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Kejing
authors.initials: K
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Jianxiang
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, P.R. China.
authors.forename: Yingchang
authors.initials: Y
authors.lastname: Mi
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D003474:Curcumin / Q000008:administration & dosage*; D005260:Female; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D006801:Humans; D020014:K562 Cells; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D020298:U937 Cells; D025721:WT1 Proteins / Q000235:genetics*; D009396:Wilms Tumor / Q000235:genetics* / Q000473:pathology; D060449:Wnt Signaling Pathway / Q000187:drug effects; D051176:beta Catenin / Q000096:biosynthesis
chemical_list: D012333:RNA, Messenger; D025721:WT1 Proteins; C583751:WT1 protein, human; D051176:beta Catenin; D003474:Curcumin