Intensive lifestyle changes may affect the progression of early, low grade prostate cancer in men. Further studies and longer term followup are warranted.

A low-fat diet and/or intensive exercise results in change in serum hormones and growth factors in vivo that can reduce growth and induce apoptosis of LNCaP prostate tumor cells in vitro.

Previous studies showed that serum from men consuming a low fat diet and undergoing exercise intervention (DE) reduced LNCaP cell growth and induced apoptosis in vitro. DE also decreased serum IGF-I and increased serum IGF binding protein-1 (IGFBP-1). The present study evaluates the effects of IGF-I and IGFBP-1 on growth and apoptosis of prostate cancer cells in vitro. When IGF-I was added to the post-DE serum, the reduction in LNCaP cell growth and the induction of apoptosis in medium containing post-DE serum alone were reversed. When IGFBP-1 was added to the pre-DE serum samples, LNCaP cell growth was reduced, and apoptosis was induced. IGF-I, long-R(3)-IGF-I (only binds IGF-I receptor), AL(31)Leu(60)-IGF-I (only binds IGFBPs), antihuman IGF-I receptor antibodies, and IGFBP-1 were then added to LNCaP cultures to determine the independent effects of IGF-I and IGFBP-1 on cell growth. Collectively, the results using these agents show that IGF-I and IGFBP-1 exert opposing effects on LNCaP cell growth and apoptosis, and IGFBP-1 acts mainly through an IGF-dependent mechanism. DE results in a decrease in serum IGF-I with increased IGFBP-1 in vivo that is associated with apoptosis and reduced LNCaP and LAPC-4 prostate cancer cell growth in vitro.