title: IRS2 silencing increases apoptosis and potentiates the effects of ruxolitinib in JAK2V617F-positive myeloproliferative neoplasms.
abstract: The recurrent V617F mutation in JAK2 (JAK2V617F) has emerged as the primary contributor to the pathogenesis of myeloproliferative neoplasms (MPN). However, the lack of complete response in most patients treated with the JAK1/2 inhibitor, ruxolitinib, indicates the need for identifying pathways that cooperate with JAK2. Activated JAK2 was found to be associated with the insulin receptor substrate 2 (IRS2) in non-hematological cells. We identified JAK2/IRS2 binding in JAK2V617F HEL cells, but not in the JAK2WT U937 cell line. In HEL cells, IRS2 silencing decreased STAT5 phosphorylation, reduced cell viability and increased apoptosis; these effects were enhanced when IRS2 silencing was combined with ruxolitinib. In U937 cells, IRS2 silencing neither reduced cell viability nor induced apoptosis. IRS1/2 pharmacological inhibition in primary MPN samples reduced cell viability in JAK2V617F-positive but not JAK2WT specimens; combination with ruxolitinib had additive effects. IRS2 expression was significantly higher in CD34+ cells from essential thrombocythemia patients compared to healthy donors, and in JAK2V617F MPN patients when compared to JAK2WT. Our data indicate that IRS2 is a binding partner of JAK2V617F in MPN. IRS2 contributes to increased cell viability and reduced apoptosis in JAK2-mutated cells. Combined pharmacological inhibition of IRS2 and JAK2 may have a potential clinical application in MPN.
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.
authors.forename: Paula
authors.initials: P
authors.lastname: de Melo Campos
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.
authors.forename: João A
authors.initials: JA
authors.lastname: Machado-Neto
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA.|Howard Hughes Medical Institute, Portland, Oregon, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Eide
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA.
authors.forename: Samantha L
authors.initials: SL
authors.lastname: Savage
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.|Current address: Department of Internal Medicine, University of São Paulo at Ribeirão Preto Medical School, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: Scopim-Ribeiro
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.
authors.forename: Adriana
authors.initials: A
authors.lastname: da Silva Souza Duarte
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.|Current address: Department of Biological Sciences, Federal University of São Paulo, Diadema, São Paulo, Brazil.
authors.forename: Patricia
authors.initials: P
authors.lastname: Favaro
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.
authors.forename: Irene
authors.initials: I
authors.lastname: Lorand-Metze
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.
authors.forename: Fernando F
authors.initials: FF
authors.lastname: Costa
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA.|Howard Hughes Medical Institute, Portland, Oregon, USA.
authors.forename: Cristina E
authors.initials: CE
authors.lastname: Tognon
authors.affiliation: Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, USA.|Howard Hughes Medical Institute, Portland, Oregon, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Druker
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.
authors.forename: Sara T
authors.initials: ST
authors.lastname: Olalla Saad
authors.affiliation: Hematology and Hemotherapy Center - University of Campinas/Hemocentro - Unicamp, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.|Current address: Department of Internal Medicine, University of São Paulo at Ribeirão Preto Medical School, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Traina
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D016022:Case-Control Studies; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D005455:Fluorescent Antibody Technique; D005500:Follow-Up Studies; D020868:Gene Silencing; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D055504:Insulin Receptor Substrate Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D053614:Janus Kinase 2 / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009196:Myeloproliferative Disorders / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D009367:Neoplasm Staging; D009570:Nitriles; D011379:Prognosis; D011720:Pyrazoles / Q000494:pharmacology*; D011743:Pyrimidines; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays; D055815:Young Adult
chemical_list: C526297:IRS2 protein, human; D055504:Insulin Receptor Substrate Proteins; D009570:Nitriles; D011720:Pyrazoles; D011743:Pyrimidines; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C540383:ruxolitinib; C507924:JAK2 protein, human; D053614:Janus Kinase 2
keywords: IRS2; JAK2V617F; STAT5; apoptosis; myeloproliferative neoplasms