title: The SIRT1 deacetylase suppresses intestinal tumorigenesis and colon cancer growth.
abstract: Numerous longevity genes have been discovered in model organisms and altering their function results in prolonged lifespan. In mammals, some have speculated that any health benefits derived from manipulating these same pathways might be offset by increased cancer risk on account of their propensity to boost cell survival. The Sir2/SIRT1 family of NAD(+)-dependent deacetylases is proposed to underlie the health benefits of calorie restriction (CR), a diet that broadly suppresses cancer in mammals. Here we show that CR induces a two-fold increase SIRT1 expression in the intestine of rodents and that ectopic induction of SIRT1 in a beta-catenin-driven mouse model of colon cancer significantly reduces tumor formation, proliferation, and animal morbidity in the absence of CR. We show that SIRT1 deacetylates beta-catenin and suppresses its ability to activate transcription and drive cell proliferation. Moreover, SIRT1 promotes cytoplasmic localization of the otherwise nuclear-localized oncogenic form of beta-catenin. Consistent with this, a significant inverse correlation was found between the presence of nuclear SIRT1 and the oncogenic form of beta-catenin in 81 human colon tumor specimens analyzed. Taken together, these observations show that SIRT1 suppresses intestinal tumor formation in vivo and raise the prospect that therapies targeting SIRT1 may be of clinical use in beta-catenin-driven malignancies.
authors.affiliation: Paul F. Glenn Laboratories for the Biological Mechanisms of Aging, Department of Pathology, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Ron
authors.initials: R
authors.lastname: Firestein
authors.forename: Gil
authors.initials: G
authors.lastname: Blander
authors.forename: Shaday
authors.initials: S
authors.lastname: Michan
authors.forename: Philipp
authors.initials: P
authors.lastname: Oberdoerffer
authors.forename: Shuji
authors.initials: S
authors.lastname: Ogino
authors.forename: Jennifer
authors.initials: J
authors.lastname: Campbell
authors.forename: Anupama
authors.initials: A
authors.lastname: Bhimavarapu
authors.forename: Sandra
authors.initials: S
authors.lastname: Luikenhuis
authors.forename: Rafael
authors.initials: R
authors.lastname: de Cabo
authors.forename: Charles
authors.initials: C
authors.lastname: Fuchs
authors.forename: William C
authors.initials: WC
authors.lastname: Hahn
authors.forename: Leonard P
authors.initials: LP
authors.lastname: Guarente
authors.forename: David A
authors.initials: DA
authors.lastname: Sinclair
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D051381:Rats; D011916:Rats, Inbred F344; D056564:Sirtuin 1; D037761:Sirtuins / Q000378:metabolism / Q000502:physiology*; D051176:beta Catenin / Q000378:metabolism
chemical_list: D051176:beta Catenin; C447939:SIRT1 protein, human; C470545:Sirt1 protein, mouse; C488368:Sirt1 protein, rat; D056564:Sirtuin 1; D037761:Sirtuins