Effect of Acute Exercise on Prostate Cancer Cell Growth

Abstract

Physical activity is associated with reduced risk of several cancers, including aggressive prostate cancer. The mechanisms mediating the effects are not yet understood; among the candidates are modifications of endogenous hormone levels. Long-term exercise is known to reduce serum levels of growth stimulating hormones. In contrast, the endocrine effects of acute endurance exercise include increased levels of mitogenic factors such as GH and IGF-1. It can be speculated that the elevation of serum growth factors may be detrimental to prostate cancer progression into malignancy. The incentive of the current study is to evaluate the effect of acute exercise serum on prostate cancer cell growth. We designed an exercise intervention where 10 male individuals performed 60 minutes of bicycle exercise at increasing intensity. Serum samples were obtained before (rest serum) and after completed exercise (exercise serum). The established prostate cancer cell line LNCaP was exposed to exercise or rest serum. Exercise serum from 9 out of 10 individuals had a growth inhibitory effect on LNCaP cells. Incubation with pooled exercise serum resulted in a 31% inhibition of LNCaP growth and pre-incubation before subcutaneous injection into SCID mice caused a delay in tumor formation. Serum analyses indicated two possible candidates for the effect; increased levels of IGFBP-1 and reduced levels of EGF. In conclusion, despite the fear of possible detrimental effects of acute exercise serum on tumor cell growth, we show that even the short-term effects seem to add to the overall beneficial influence of exercise on neoplasia.

Effects of acute physical exercise on oxidative stress and inflammatory status in young, sedentary obese subjects

“…The EGF interaction with its receptor leads to the activation of NADPH oxidase and the consequent production of ROS, which, in turn, stimulate the autophosphorylation of the membrane receptor and the induction of the signal cascade [72]. It is plausible that the post-exercise EGF reduction, an already reported finding [67], is finalized to facilitate defense mechanisms against oxidative stress. This hypothesis is supported by the proportional reduction in EGF levels in association with increasing BMI, concurrently with the exacerbation of oxidative stress levels in obese subjects.…”

Physical Activity and Survival among Men Diagnosed with Prostate Cancer

“…Regular exercise has been shown to affect the IGF axis resulting in lower levels of serum insulin and IGF1 and increased levels of IGF-binding protein-1 in vivo with reduced proliferation and increased apoptosis of prostate tumor cells in vitro (21,22). A recent study also showed that serum extracted directly after strenuous exercise reduced the proliferation of prostate tumor cells in vitro, indicating an acute effect of physical activity on tumor growth (23). Altered levels of adipokines is an effect of obesity and also associated with tumor development (24).…”

Effects of Exercise on Tumor Physiology and Metabolism

“…In this study, muscles were electrically stimulated to fatigue, and extracts from the exhausted muscles were injected directly into transplanted tumors in rats and shown to slow the growth of the tumors. 57,58 Using comparable conditioned media from cultured muscle cells for incubation of cancer cells in vitro, such media significantly reduces cancer cell growth. 55 The skeletal muscle is now recognized as an endocrine organ that secretes peptides during muscle contraction.…”