title: LKB1 deficiency sensitizes mice to carcinogen-induced tumorigenesis.
abstract: Lkb1 is a central regulator of cell polarity and energy metabolism through its capacity to activate the AMP-activated protein kinase (AMPK)-related family of protein kinases. Germ line-inactivating mutation of Lkb1 leads to Peutz-Jeghers syndrome, which is characterized by benign hamartomas and a susceptibility to malignant epithelial tumors. Mutations in Lkb1 are also found in sporadic carcinomas, most frequently in lung cancers associated with tobacco carcinogen exposure. The basis for Lkb1-dependent tumor suppression is not defined. Here, we uncover a marked sensitivity of Lkb1 mutant mice to the chemical carcinogen 7,12-dimethylbenz(a)anthracene (DMBA). Lkb1(+/-) mice are highly prone to DMBA-induced squamous cell carcinoma (SCC) of the skin and lung. Confirming a cell autonomous tumor suppressor role of Lkb1, mice with epidermal-specific Lkb1 deletion are also susceptible to DMBA-induced SCC and develop spontaneous SCC with long latency. Restoration of wild-type Lkb1 causes senescence in tumor-derived cell lines, a process that can be partially bypassed by inactivation of the Rb pathway, but not by inactivation of p53 or AMPK. Our data indicate that Lkb1 is a potent suppressor of carcinogen-induced skin and lung cancers and that downstream targets beyond the AMPK-mTOR pathway are likely mediators of Lkb1-dependent tumor suppression.
authors.affiliation: Massachusetts General Hospital, Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02114, USA.
authors.forename: Sushma
authors.initials: S
authors.lastname: Gurumurthy
authors.forename: Aram F
authors.initials: AF
authors.lastname: Hezel
authors.forename: Ergun
authors.initials: E
authors.lastname: Sahin
authors.forename: Justin H
authors.initials: JH
authors.lastname: Berger
authors.forename: Marcus W
authors.initials: MW
authors.lastname: Bosenberg
authors.forename: Nabeel
authors.initials: N
authors.lastname: Bardeesy
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000633:toxicity; D055372:AMP-Activated Protein Kinases; D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D004817:Epidermis / Q000187:drug effects / Q000473:pathology; D008175:Lung Neoplasms / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008817:Mice, Mutant Strains; D018307:Neoplasms, Squamous Cell / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency* / Q000235:genetics; D016160:Retinoblastoma Protein / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction; D012878:Skin Neoplasms / Q000139:chemically induced / Q000235:genetics* / Q000473:pathology; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D002273:Carcinogens; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D015127:9,10-Dimethyl-1,2-benzanthracene; D017346:Protein Serine-Threonine Kinases; C491654:Stk11 protein, mouse; D055372:AMP-Activated Protein Kinases