title: Inhibition of the TGF-beta receptor I kinase promotes hematopoiesis in MDS.
abstract: MDS is characterized by ineffective hematopoiesis that leads to peripheral cytopenias. Development of effective treatments has been impeded by limited insight into pathogenic pathways governing dysplastic growth of hematopoietic progenitors. We demonstrate that smad2, a downstream mediator of transforming growth factor-beta (TGF-beta) receptor I kinase (TBRI) activation, is constitutively activated in MDS bone marrow (BM) precursors and is overexpressed in gene expression profiles of MDS CD34(+) cells, providing direct evidence of overactivation of TGF-beta pathway in this disease. Suppression of the TGF-beta signaling by lentiviral shRNA-mediated down-regulation of TBRI leads to in vitro enhancement of hematopoiesis in MDS progenitors. Pharmacologic inhibition of TBRI (alk5) kinase by a small molecule inhibitor, SD-208, inhibits smad2 activation in hematopoietic progenitors, suppresses TGF-beta-mediated gene activation in BM stromal cells, and reverses TGF-beta-mediated cell-cycle arrest in BM CD34(+) cells. Furthermore, SD-208 treatment alleviates anemia and stimulates hematopoiesis in vivo in a novel murine model of bone marrow failure generated by constitutive hepatic expression of TGF-beta1. Moreover, in vitro pharmacologic inhibition of TBRI kinase leads to enhancement of hematopoiesis in varied morphologic MDS subtypes. These data directly implicate TGF-beta signaling in the pathobiology of ineffective hematopoiesis and identify TBRI as a potential therapeutic target in low-risk MDS.
authors.affiliation: Albert Einstein College of Medicine, Bronx, NY, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.forename: Aaron N
authors.initials: AN
authors.lastname: Nguyen
authors.forename: Davendra
authors.initials: D
authors.lastname: Sohal
authors.forename: Jing
authors.initials: J
authors.lastname: Ying Ma
authors.forename: Perry
authors.initials: P
authors.lastname: Pahanish
authors.forename: Krishna
authors.initials: K
authors.lastname: Gundabolu
authors.forename: Josh
authors.initials: J
authors.lastname: Hayman
authors.forename: Adam
authors.initials: A
authors.lastname: Chubak
authors.forename: Yongkai
authors.initials: Y
authors.lastname: Mo
authors.forename: Tushar D
authors.initials: TD
authors.lastname: Bhagat
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Das
authors.forename: Ann M
authors.initials: AM
authors.lastname: Kapoun
authors.forename: Tony A
authors.initials: TA
authors.lastname: Navas
authors.forename: Simrit
authors.initials: S
authors.lastname: Parmar
authors.forename: Suman
authors.initials: S
authors.lastname: Kambhampati
authors.forename: Andrea
authors.initials: A
authors.lastname: Pellagatti
authors.forename: Ira
authors.initials: I
authors.lastname: Braunchweig
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Amittha
authors.initials: A
authors.lastname: Wickrema
authors.forename: Satyanarayana
authors.initials: S
authors.lastname: Medicherla
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Boultwood
authors.forename: Leonidas C
authors.initials: LC
authors.lastname: Platanias
authors.forename: Linda S
authors.initials: LS
authors.lastname: Higgins
authors.forename: Alan F
authors.initials: AF
authors.lastname: List
authors.forename: Markus
authors.initials: M
authors.lastname: Bitzer
authors.forename: Amit
authors.initials: A
authors.lastname: Verma
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D018952:Antigens, CD34 / Q000096:biosynthesis; D001853:Bone Marrow / Q000187:drug effects / Q000473:pathology; D005260:Female; D006410:Hematopoiesis; D006801:Humans; D016086:Lentivirus / Q000235:genetics; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008875:Middle Aged; D008954:Models, Biological; D009190:Myelodysplastic Syndromes / Q000378:metabolism* / Q000473:pathology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011621:Pteridines / Q000494:pharmacology; D000077293:Receptor, Transforming Growth Factor-beta Type I; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D018952:Antigens, CD34; D011621:Pteridines; D018125:Receptors, Transforming Growth Factor beta; C511004:SD-208; D017346:Protein Serine-Threonine Kinases; D000077293:Receptor, Transforming Growth Factor-beta Type I; C000625841:TGFBR1 protein, human; C000625842:Tgfbr1 protein, mouse