Exercise Associated Genes in Rat Colon Mucosa: Upregulation of Ornithin Decarboxylase-1

Abstract

Epidemiology has revealed that physical activity is an important lifestyle factor that reduces the risk of colon cancer. However, the underlying mechanisms of this protective effect have so far not been defined. The aim of this study was to identify molecular targets of physical activity in rat colon mucosa by employing our voluntary exercise model. Twenty male rats underwent a 12-week exercise program, with 9 additional rats serving as a control group. Running distances, body weights and heart weights as measures of physical adaptations were recorded, and changes in mRNA steady-state levels of marker genes involved in vascularization (VEGF, HIF-1α, ODC-1), apoptosis (Bcl-2, PPARγ) and prostaglandin synthesis (COX-2) were determined by qRT‐PCR. The four housekeeping genes GAPDH, β-actin, 18S and ALDA served as reference genes. Recorded running distances showed great inter-individual differences resulting in three different groups of low (L‐EX, < 2629 m/night; n = 5), moderate (M‐EX, 3003 - 7458 m/night; n = 10) and high (H‐EX, > 8314 m/night; n = 5) physical activity. The M‐EX and H‐EX group revealed significant (p < 0.05) adaptive changes with an increase in heart mass per kg body weight and a decrease in mean body weight. Amongst the marker genes studied by mRNA expression analysis only ODC-1 appears to be differentially expressed. Its 1.8-fold increased steady-state mRNA level in the H‐EX group suggests that synthesis of polyamines may be increased by physical activity. This new finding could provide a link between extensive physical activity and its protective effects on colon cancer development.

ODC-1 - colon mucosa - gene expression - real-time RT-PCR - cancer prevention - housekeeping genes

References

• 1 Allen D L, Harrison B C, Maass A, Bell M L, Byrnes W C, Leinwand L A. Cardiac and skeletal muscle adaptations to voluntary wheel running in the mouse.  J Appl Physiol. 2001;  90 1900-1908
• 2 American Cancer Society .Cancer Facts and Figures. Atlanta; American Cancer Society 2005
• 3 Andrianopoulos G, Nelson R L, Bombeck C T, Souza G. The influence of physical activity in 1, 2-dimethylhydrazine induced colon carcinogenesis in the rat.  Anticancer Res. 1987;  7 849-852
• 4 Bryner R W, Donley D A, Cutpil R G, Wirth O, Alway S E. Effects of downhill treadmill running on uncoupling protein 3 mRNA expression.  Int J Sports Med. 2004;  25 433-437
• 5 Calviello G, DiNicuolo F, Gragnoli S, Piccioni E, Serini S, Maggiano N, Tringali G, Navarra P, Ranelletti F O, Palazzo P. n-3PUFAs reduce VEGF expression in human colon cancer cells modulating the COX‐2/PGE2 induced ERK‐1 and -2 and HIF-1alpha induction pathway.  Carcinogenesis. 2004;  25 2303-2310
• 6 Colbert L H, Davis J M, Essig D A, Ghaffar A, Mayer E P. Exercise and tumor development in a mouse predisposed to multiple intestinal adenomas.  Med Sci Sports Exerc. 2000;  32 1704-1708
• 7 Colbert L H, Mai V, Perkins S N, Berrigan D, Lavigne J A, Wimbrow H H, Alvord W G, Haines D C, Srinivas P, Hursting S D. Exercise and intestinal polyp development in APCMin mice.  Med Sci Sports Exerc. 2003;  35 1662-1669
• 8 Fehrenbach E, Northoff H. Free radicals, exercise, apoptosis, and heat shock proteins.  Exerc Immunol Rev. 2001;  7 66-89
• 9 Ferrara N, Houck K, Jakeman L, Leung D W. Molecular and biological properties of the vascular endothelial growth factor family of proteins.  Endocr Rev. 1992;  13 18-32
• 10 Friedenreich C M, Orenstein M R. Physical activity and cancer prevention: etiologic evidence and biological mechanisms.  J Nutr. 2002;  132 3456S-3464S
• 11 Jemiolo B, Trappe S. Single muscle fiber gene expression in human skeletal muscle: validation of internal control with exercise.  Biochem Biophys Res Commun. 2004;  320 1043-1050
• 12 Kingwell B A, Arnold P J, Jennings G L, Dart A M. The effects of voluntary running on caridac mass and aortic compliance in Wistar-Kyoto and spontaneously hypertensive rats.  J Hypertens. 1998;  16 181-185
• 13 Leung P-S, Aronson W J, Ngo T H, Golding L A, Barnard R J. Exercise alters the IGF axis in vivo and increases p53 protein in prostate tumor cells in vitro.  J Appl Physiol. 2003;  96 450-454
• 14 Mahoney D J, Carey K, Fu M H, Snow R, Cameron-Smith D, Parise G, Tarnopolsky M A. Real-time RT‐PCR analysis of housekeeping genes in human skeletal muscle following acute exercise.  Physiol Genomics. 2004;  18 226-231
• 15 Martinez M E, Heddens D, Earnest D L, Bogert C L, Roe D, Einspahr J, Marshall J R, Alberts D S. Physical activity, body mass index, and prostaglandin E2 levels in rectal mucosa.  J Natl Cancer Inst. 1999;  91 950-953
• 16 Murphy R M, Watt K K, Cameron-Smith D, Gibbons C J, Snow R J. Effects of creatine supplementation on housekeeping genes in human skeletal muscle using real-time RT‐PCR.  Physiol Genomics. 2003;  12 163-174
• 17 Pfaffl M W, Horgan G W, Dempfle L. Relative expression software tool (REST) for group-wise comparison and statistical analysis of relative expression results in real-time PCR.  Nucl Acids Res. 2002;  30 e36
• 18 Pfaffl M W, Tichopad A, Progmet C, Neuvians T P. Determination of stable housekeeping genes, differentially regulated target genes and sample integrity: BestKeeper - Excel-based tool using pair-wise correlations.  Biotechnology Letters. 2004;  26 509-515
• 19 Pugh S, Thomas G A. Patients with adenomatous polyps and carcinomas have increased colonic mucosal prostaglandin E2.  Gut. 1994;  35 675-678
• 20 Quadrilatero J, Hoffman-Goetz L. Physical activity and colon cancer. A systematic review of potential mechanisms.  J Sports Med Phys Fitness. 2003;  43 121-138
• 21 Rasmussen R. Quantification on the LightCycler Instrument. Heidelberg; Springer-Verlag 2001
• 22 Reddy B S, Sugie S, Lowenfels A. Effect of voluntary exercise on azoxymethane-induced colon carcinogesis in F344 rats.  Cancer Res. 1988;  48 7079-7081
• 23 Schipper R G, Verhofstad A AJ. Distribution patterns of ornithine decarboxylase in cells and tissues: facts, problems, and postulates.  J Histochem Cytochem. 2002;  50 1143-1160
• 24 Thellin O, Zorzi W, Lakaye B, De Borman B, Coumans B, Hennen G, Grisar T, Igout A, Heinen E. Housekeeping genes as internal standards: use and limits.  J Biotechnol. 1999;  8 291-295
• 25 Thorling E B, Jacobsen N O, Overvad K. Effect of exercise on intestinal tumor development in the male Fischer rat after exposure to axozymethane.  Eur J Cancer Prev. 1993;  2 77-82
• 26 Thorling E B, Jacobsen N O, Overvad K. The effect of treadmill exercise on azoxymethane-induced intestinal neoplasia in the male Fischer rat on two different high-fat diets.  Nutr Cancer. 1994;  22 31-41
• 27 Tsuji N, Kamagata C, Furuya M, Kobayashi D, Yagihashi A, Morita T, Horita S, Watanabe N. Selection of an internal control gene for quantification of mRNA in colonic tissues.  Anticancer Res. 2002;  22 4173-4178
• 28 Turchanowa L, Rogozkin V A, Milovic V, Feldkoren B I, Caspary W F, Stein J. Influence of physical exercise on polyamine synthesis in the rat skeletal muscle.  Eur J Clin Invest. 2000;  30 72-78
• 29 von Deutsch A W, Mitchell C D, Williams C E, Dutt K, Silvestrov N A, Klement B J, Abukhalaf I K, von Deutsch D A. Polyamines protect against radiation-induced oxidative stress.  Gravit Space Biol Bull. 2005;  18 109-110