title: Phosphorylated CIS suppresses the Epo or JAK2 V617F mutant-triggered cell proliferation through binding to EpoR.
abstract: The JAK2 V617F mutant-mediated aberrant signaling pathway is a hallmark of myeloproliferative neoplasms (MPNs). Although cytokine-inducible Src homology 2 protein (CIS) and suppressors of cytokine signaling (SOCS) are negative regulators of the JAK-STAT pathway, the functional role of CIS/SOCS family members in the JAK2 V617F mutant-induced oncogenic signaling pathway has not yet been elucidated. In this study, we found that the expression of CIS and SOCS1 was induced through the activation of signal transducer and activator of transcription 5 (STAT5) in not only the cells stimulated with Epo or IL-3 but also the cells transformed by the JAK2 V617F mutant. Cell proliferation and tumor formation in nude mice induced by the JAK2 V617F mutant were significantly enhanced when the expression of CIS was silenced using an RNA interference technique, whereas the knockdown of SOCS1 had no effect. The enforced expression of CIS caused apoptotic cell death in the transformed by JAK2 V617F mutant and drastically inhibited the JAK2 V617F mutant-induced tumor formation. CIS interacted with phosphorylated EpoR at Y401, which was critical for the activation of STAT5 and ERK. Whereas the activation of STAT5 and ERK in the transformed cells by JAK2 V617F mutant was increased by the knockdown of CIS, the enforced expression of CIS reduced the activation of these molecules. Furthermore, these anti-tumor effects of CIS required the function of SH2 domain and its tyrosine phosphorylation at Y253. We herein elucidated the mechanism by which CIS functions as a novel type of tumor suppressor in JAK2 V617F mutant-induced tumorigenesis.
authors.affiliation: Department of Hygienic Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan. Electronic address: tago-mg@pha.keio.ac.jp.
authors.forename: Megumi
authors.initials: M
authors.lastname: Funakoshi-Tago
authors.affiliation: Department of Hygienic Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Moriwaki
authors.affiliation: Department of Hygienic Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan.
authors.forename: Fumihito
authors.initials: F
authors.lastname: Ueda
authors.affiliation: Department of Hygienic Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan.
authors.forename: Hiroomi
authors.initials: H
authors.lastname: Tamura
authors.affiliation: Department of Hygienic Chemistry, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan; Iternational University of Health and Welfare, Graduate School, 1-3-3 Minamiaoyama, Minato-ku, Tokyo, 107-0062, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kasahara
authors.affiliation: Division of Structural Biochemistry, Department of Biochemistry, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi-ken 329-0498, Japan. Electronic address: ktago@jichi.ac.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Tago
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D063646:Carcinogenesis / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000378:metabolism / Q000473:pathology; D004921:Erythropoietin / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D053614:Janus Kinase 2 / Q000378:metabolism*; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008954:Models, Biological; D009154:Mutation / Q000235:genetics*; D010766:Phosphorylation; D011485:Protein Binding; D017467:Receptors, Erythropoietin / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism; D050826:Suppressor of Cytokine Signaling Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004921:Erythropoietin; D048049:Extracellular Signal-Regulated MAP Kinases; D053614:Janus Kinase 2; D017467:Receptors, Erythropoietin; D050799:STAT5 Transcription Factor; D050826:Suppressor of Cytokine Signaling Proteins
keywords: CIS; JAK2; Myeloproliferative neoplasms (MPNs); SOCS1; V617F mutation