Submitted to: Anticancer Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 24, 2011
Publication Date: October 1, 2011
Citation: Yan, L., Demars, L.C. 2011. Effects of non-motorized voluntary running on experimental and spontaneous metastasis in mice. Anticancer Research. 31:3337-3344. Interpretive Summary: The present study investigated the effects of non-motorized voluntary running on experimental metastasis of B16BL/6 melanoma and spontaneous metastasis of Lewis lung carcinoma (LLC) in male C57BL/6 mice. After 9 weeks of running, mice received an intravenous injection of B16BL/6 cells or a subcutaneous injection of LLC cells, and then they were continued on their running activities. Mice were terminated 2 weeks after the intravenous injection of B16BL/6 cells or 2 weeks after surgical removal of the primary tumor from mice injected with LLC cells. Mice in the running group ran an average of 4-6 km/day for the duration of the experiment. Voluntary exercise decreased body weight compared with the sedentary controls, but there were no differences in the number and the size of lung metastases between the groups for both experimental and spontaneous metastasis. Voluntary exercise significantly decreased plasma insulin and leptin and increased adiponectin in both non-LLC-bearing and LLC-bearing mice compared with the sedentary controls. Bearing LLC significantly increased plasma concentrations of vascular endothelial growth factor (VEGF), platelet-derived growth factor-BB (PDGF-BB), PDGF-AB and monocyte chemoattractant protein-1 (MCP-1) in mice. Voluntary exercise significantly increased plasma PDGF-BB and PDGF-AB, but not VEGF and MCP-1, in LLC-bearing mice compared to their sedentary counterparts. In conclusion, voluntary running was favorable to body weight and the expression of related adipokines, but at 4-6 km/day it did not affect either experimental or spontaneous metastasis in mice. Voluntary exercise-stimulated over-expression of PDGF in tumor-bearing animals warrants further investigation.
Technical Abstract: Physical activity is any form of movement using skeletal muscles. Human population and laboratory studies show that physical exercise may play a favorable role in primary cancer prevention.The present study investigated the effects of voluntary exercise on the development and growth of secondary cancer (the spread of malignant cells from a primary tumor to distant organs) in laboratory animals. On a voluntary basis, male mice ran an average of 4-6 km/day for the duration of the experiment (13 weeks). Voluntary exercise favorably decreased body weight, abdominal adiposity and the expression of related adipocytokines (e.g. insulin, leptin) in mice compared with the sedentary controls, but there were no differences in the number of tumors developed in the lungs. Interestingly, voluntary exercise significantly increased plasma concentration of platelet-derived growth factor, which plays a significant role in blood vessel formation, in tumor-bearing mice compared to their sedentary counterparts.In conclusion, voluntary running at 4-6 km/day did not affect the development and growth of secondary cancer in mice. Voluntary exercise-stimulated over-expression of platelet-derived growth factor in tumor-bearing animals warrants further investigation.