title: A mouse model of TSC1 reveals sex-dependent lethality from liver hemangiomas, and up-regulation of p70S6 kinase activity in Tsc1 null cells.
abstract: Tuberous sclerosis (TSC) is a autosomal dominant genetic disorder caused by mutations in either TSC1 or TSC2, and characterized by benign hamartoma growth. We developed a murine model of Tsc1 disease by gene targeting. Tsc1 null embryos die at mid-gestation from a failure of liver development. Tsc1 heterozygotes develop kidney cystadenomas and liver hemangiomas at high frequency, but the incidence of kidney tumors is somewhat lower than in Tsc2 heterozygote mice. Liver hemangiomas were more common, more severe and caused higher mortality in female than in male Tsc1 heterozygotes. Tsc1 null embryo fibroblast lines have persistent phosphorylation of the p70S6K (S6K) and its substrate S6, that is sensitive to treatment with rapamycin, indicating constitutive activation of the mTOR-S6K pathway due to loss of the Tsc1 protein, hamartin. Hyperphosphorylation of S6 is also seen in kidney tumors in the heterozygote mice, suggesting that inhibition of this pathway may have benefit in control of TSC hamartomas.
authors.affiliation: Genetics Laboratory, Hematology Division, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, LM-302, Boston, MA 02115, USA. dk@rics.bwh.harvard.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Kwiatkowski
authors.forename: Hongbing
authors.initials: H
authors.lastname: Zhang
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Bandura
authors.forename: Kristina M
authors.initials: KM
authors.lastname: Heiberger
authors.forename: Michael
authors.initials: M
authors.lastname: Glogauer
authors.forename: Nisreen
authors.initials: N
authors.lastname: el-Hashemite
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Onda
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002999:Clone Cells; D003537:Cystadenoma / Q000235:genetics / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D016147:Genes, Tumor Suppressor; D005838:Genotype; D018095:Germ-Line Mutation; D006391:Hemangioma / Q000235:genetics* / Q000401:mortality* / Q000473:pathology; D006579:Heterozygote; D007680:Kidney Neoplasms / Q000235:genetics / Q000473:pathology; D008113:Liver Neoplasms / Q000235:genetics* / Q000401:mortality* / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D010641:Phenotype; D011506:Proteins / Q000235:genetics*; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism*; D012737:Sex Factors; D013234:Stem Cells; D015996:Survival Rate; D000077004:Tuberous Sclerosis Complex 1 Protein; D025521:Tumor Suppressor Proteins; D015854:Up-Regulation
chemical_list: D011506:Proteins; C000624651:Tsc1 protein, mouse; D000077004:Tuberous Sclerosis Complex 1 Protein; D025521:Tumor Suppressor Proteins; D019893:Ribosomal Protein S6 Kinases