title: Rb1 haploinsufficiency promotes telomere attrition and radiation-induced genomic instability.
abstract: Germline mutations of the retinoblastoma gene (RB1) predispose to both sporadic and radiation-induced osteosarcoma, tumors characterized by high levels of genomic instability, and activation of alternative lengthening of telomeres. Mice with haploinsufficiency of the Rb1 gene in the osteoblastic lineage reiterate the radiation susceptibility to osteosarcoma seen in patients with germline RB1 mutations. We show that the susceptibility is accompanied by an increase in genomic instability, resulting from Rb1-dependent telomere erosion. Radiation exposure did not accelerate the rate of telomere loss but amplified the genomic instability resulting from the dysfunctional telomeres. These findings suggest that telomere maintenance is a noncanonical caretaker function of the retinoblastoma protein, such that its deficiency in cancer may potentiate DNA damage-induced carcinogenesis by promoting formation of chromosomal aberrations, rather than simply by affecting cell-cycle control.
authors.affiliation: Institute of Radiation Biology, Helmholtz Zentrum München, Neuherberg, Germany.
authors.forename: Iria
authors.initials: I
authors.lastname: Gonzalez-Vasconcellos
authors.forename: Natasa
authors.initials: N
authors.lastname: Anastasov
authors.forename: Bahar
authors.initials: B
authors.lastname: Sanli-Bonazzi
authors.forename: Olena
authors.initials: O
authors.lastname: Klymenko
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Atkinson
authors.forename: Michael
authors.initials: M
authors.lastname: Rosemann
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000235:genetics; D059447:Cell Cycle Checkpoints / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D016161:Genes, Retinoblastoma; D020022:Genetic Predisposition to Disease; D042822:Genomic Instability / Q000528:radiation effects*; D057895:Haploinsufficiency; D051379:Mice; D012516:Osteosarcoma / Q000235:genetics; D011827:Radiation; D016160:Retinoblastoma Protein / Q000235:genetics*; D016615:Telomere / Q000235:genetics / Q000378:metabolism*
chemical_list: D016160:Retinoblastoma Protein