title: Dysregulation of the mTOR pathway in p53-deficient mice.
abstract: Mammalian or mechanistic target of rapamycin (mTOR) is involved in growth, aging, and age-related diseases including cancer. There is an extensive cross talk between p53 and mTOR. In cell culture, p53 inhibits the mTOR pathway in a cell type-dependent manner. p53-deficient mice develop pro-inflammation and cancer. We have shown that rapamycin delayed cancer and extended lifespan, thus partially substituting for p53. Here we show that a marker of mTOR activity, phosphorylated S6 (p-S6), is increased in the hearts of p53-deficient mice. Furthermore, cardiac p-S6 correlated with body weight. Also, p53(-/-) mice were slightly hyperinsulinemic with a tendency to elevated IGF-1. Radiation exacerbated the difference between IGF-1 levels in normal and p53(-/-) mice. Noteworthy, radiation induced Thr-308 Akt phosphorylation in the livers (but not in the hearts) of both p53(+/+) and p53(-/-) mice. Simultaneously, radiation decreased p-S6 in the livers of normal mice, consistent with the negative effect of p53 on mTOR. Our data indicate that the activity of mTOR is increased in some but not all tissues of p53(-/-) mice, associated with the tendency to increased insulin and IGF-1 levels. Therefore, the absence of p53 may create oncophilic microenvironment, favoring cancer.
authors.affiliation: Department of Cell Stress Biology; Roswell Park Cancer Institute; Buffalo, NY USA.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Leontieva
authors.affiliation: Department of Cell Stress Biology; Roswell Park Cancer Institute; Buffalo, NY USA.
authors.forename: Liliya R
authors.initials: LR
authors.lastname: Novototskaya
authors.affiliation: Department of Cell Stress Biology; Roswell Park Cancer Institute; Buffalo, NY USA.
authors.forename: Geraldine M
authors.initials: GM
authors.lastname: Paszkiewicz
authors.affiliation: Department of Cell Stress Biology; Roswell Park Cancer Institute; Buffalo, NY USA.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Komarova
authors.affiliation: Department of Cell Stress Biology; Roswell Park Cancer Institute; Buffalo, NY USA.
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Gudkov
authors.affiliation: Department of Cell Stress Biology; Roswell Park Cancer Institute; Buffalo, NY USA.
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Blagosklonny
mesh_terms: D000818:Animals; D008099:Liver / Q000378:metabolism; D018345:Mice, Knockout; D009206:Myocardium / Q000378:metabolism; D009928:Organ Specificity; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000235:genetics; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
chemical_list: D016159:Tumor Suppressor Protein p53; C546843:mTOR protein, mouse; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases
keywords: aging; cancer; inflammation; mTOR; p53; rapalog; rapamycin; senescence