title: Mammalian sterile 20-like kinase 1 suppresses lymphoma development by promoting faithful chromosome segregation.
abstract: The mammalian Hippo signaling pathway has been implicated in oncogenesis in the context of solid tumors such as hepatocellular carcinoma. Mammalian sterile 20-like kinase 1 (MST1), the core component of the Hippo signaling pathway, is highly expressed in hematopoietic cells. However, its possible impact on tumorigenesis in this setting is unknown. In this study, we provide evidence that Mst1 loss in the mouse enhances chemically and genetically induced lymphoma development by inducing chromosomal instability. Mst1 deficiency increased susceptibility to T-cell acute lymphoblastic leukemia induced by mutagen exposure. Notably, before transformation Mst1(-/-) normal thymocytes showed no changes in proliferation or apoptosis in vitro and in vivo, but they displayed elevated levels of abnormal mitotic chromosomes and aneuploidy, conditions known to promote tumorigenesis. Mst1(-/-) mice also showed accelerated formation of spontaneous lymphomas in a p53-deficient background, accompanied by severe aneuploidy. In clinical specimens of lymphoma and leukemia, we documented frequent downregulation of MST1 expression, consistent with our findings. Taken together, our findings reveal a tumor suppressive function of Mst1 based on its ability to prevent chromosomal instability in lymphocytes.
authors.affiliation: Authors' Affiliations: Department of Biological Sciences, National Creative Research Initiatives Center, Graduate School of Nanoscience and Technology (WCU), Korea Advanced Institute of Science and Technology, Daejeon, Korea.
authors.forename: Tae-Shin
authors.initials: TS
authors.lastname: Kim
authors.forename: Da-Hye
authors.initials: DH
authors.lastname: Lee
authors.forename: Sang Kyum
authors.initials: SK
authors.lastname: Kim
authors.forename: So Youn
authors.initials: SY
authors.lastname: Shin
authors.forename: Eul-Ju
authors.initials: EJ
authors.lastname: Seo
authors.forename: Dae-Sik
authors.initials: DS
authors.lastname: Lim
mesh_terms: D000818:Animals; D043171:Chromosomal Instability; D002875:Chromosomes; D008223:Lymphoma / Q000201:enzymology / Q000517:prevention & control*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D000099317:Hippo Kinases
chemical_list: D017346:Protein Serine-Threonine Kinases; C490660:Stk4 protein, mouse; D000099317:Hippo Kinases