title: Calorie restriction decreases murine and human pancreatic tumor cell growth, nuclear factor-κB activation, and inflammation-related gene expression in an insulin-like growth factor-1-dependent manner.
abstract: Calorie restriction (CR) prevents obesity and has potent anticancer effects that may be mediated through its ability to reduce serum growth and inflammatory factors, particularly insulin-like growth factor (IGF)-1 and protumorigenic cytokines. IGF-1 is a nutrient-responsive growth factor that activates the inflammatory regulator nuclear factor (NF)-κB, which is linked to many types of cancers, including pancreatic cancer. We hypothesized that CR would inhibit pancreatic tumor growth through modulation of IGF-1-stimulated NF-κB activation and protumorigenic gene expression. To test this, 30 male C57BL/6 mice were randomized to either a control diet consumed ad libitum or a 30% CR diet administered in daily aliquots for 21 weeks, then were subcutaneously injected with syngeneic mouse pancreatic cancer cells (Panc02) and tumor growth was monitored for 5 weeks. Relative to controls, CR mice weighed less and had decreased serum IGF-1 levels and smaller tumors. Also, CR tumors demonstrated a 70% decrease in the expression of genes encoding the pro-inflammatory factors S100a9 and F4/80, and a 56% decrease in the macrophage chemoattractant, Ccl2. Similar CR effects on tumor growth and NF-κB-related gene expression were observed in a separate study of transplanted MiaPaCa-2 human pancreatic tumor cell growth in nude mice. In vitro analyses in Panc02 cells showed that IGF-1 treatment promoted NF-κB nuclear localization, increased DNA-binding of p65 and transcriptional activation, and increased expression of NF-κB downstream genes. Finally, the IGF-1-induced increase in expression of genes downstream of NF-κB (Ccdn1, Vegf, Birc5, and Ptgs2) was decreased significantly in the context of silenced p65. These findings suggest that the inhibitory effects of CR on Panc02 pancreatic tumor growth are associated with reduced IGF-1-dependent NF-κB activation.
authors.affiliation: Department of Nutritional Sciences, University of Texas, Austin, Austin, Texas, United States of America.
authors.forename: Alison E
authors.initials: AE
authors.lastname: Harvey
authors.affiliation: Department of Nutritional Sciences, University of Texas, Austin, Austin, Texas, United States of America.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Lashinger
authors.affiliation: Department of Nutritional Sciences, University of Texas, Austin, Austin, Texas, United States of America.
authors.forename: Drew
authors.initials: D
authors.lastname: Hays
authors.affiliation: Department of Nutritional Sciences, University of Texas, Austin, Austin, Texas, United States of America.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Harrison
authors.affiliation: Department of Nutritional Sciences, University of Texas, Austin, Austin, Texas, United States of America.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Lewis
authors.affiliation: Department of Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas, United States of America.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Fischer
authors.affiliation: Department of Nutritional Sciences, University of Texas, Austin, Austin, Texas, United States of America; Department of Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas, United States of America.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Hursting
mesh_terms: D000818:Animals; D031204:Caloric Restriction; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000097:blood / Q000378:metabolism*
chemical_list: D016328:NF-kappa B; D007334:Insulin-Like Growth Factor I