Prostate cancer lycopene

An evaluation of the Health Professionals Follow-Up Study (Giovannucci et al., 1995) has detected a lower prostate cancer risk associated with the greater consumption of tomatoes and related food products. Tomatoes are the primary dietary source of lycopene and lycopene concentrations are highest in testis and adrenal tissue (Clinton, 1998). In paired benign and malignant prostate tissue from 25 American men, 53-74 yrs, undergoing... 

J w, Jr. (1996) Cis-trans lycopene isomers, carotenoids and retinol in the human prostate. Cancer Epidemiol Biomarkers Prev. 5(10) 823-33. 

GANN P H, GIOVANNUCCI E, WILLETT W, SACHS F H, HENNEKENS C H and STAMPFER M I (1999) Lower prostate cancer risk in men with elevated plasma lycopene levels results of a prospective analysis , Cancer Res, 59, 1225-30. 

GIOVANNUCCI E, RIMM E B, LIU Y, STAMPFER M J and WILLETT w c (2002) A prospective study of tomato products, lycopene and prostate cancer risk , J Natl Cancer Inst, 94, 391-8. 

Carotenoids and prostate cancer — Numerous epidemiological studies including prospective cohort and case-control studies have demonstrated the protective roles of lycopene, tomatoes, and tomato-derived products on prostate cancer risk other carotenoids showed no effects. " In two studies based on correlations between plasma levels or dietary intake of various carotenoids and prostate cancer risk, lycopene appeared inversely associated with prostate cancer but no association was reported for a-carotene, P-carotene, lutein, zeaxanthin, or p-cryptoxanthin. - Nevertheless, a protective role of all these carotenoids (provided by tomatoes, pumpkin, spinach, watermelon, and citrus fruits) against prostate cancer was recently reported by Jian et al. ... 

Intervention trials confirmed this protective role of lycopene on prostate cancer risk. Three primary intervention studies evaluated the effect of lycopene supplementation on prostate cancer risk or on certain risk markers such as prostate-specific antigen (PSA) plasma concentration or oxidative alterations of leucocyte DNA. - All showed increases of plasma and prostate lycopene levels after diet supplementation with lycopene and inverse correlations between tumor incidence and risk biomarkers. 

The second major difficulty is that cells and tissues in the body are exposed to numerous metabolites displaying different structures compared to the parent molecules present in plant foods. For example, it has been suggested that the metabolites of lycopene may be responsible for reducing the risk of developing prostate cancer. These metabolites may interact with nuclear receptors such as PPARs, LXR, and others. " Future research is needed to produce metabolites (enzymatically or chemically) in order to elucidate their cellular mechanisms and thus clarify their effects on human health. 

Etminan, M. et al.. The role of tomato products and lycopene in the prevention of prostate cancer a meta-analysis of observational studies. Cancer Epidemiol. Biomarkers Prev., 13, 340, 2004. 

Jian, L. et al.. Do dietary lycopene and other carotenoids protect against prostate cancer Int. J. Cancer, 113, 1010, 2005. 

Kucuk, O. et al.. Effects of lycopene supplementation in patients with localized prostate cancer, Exp. Biol. Med. (Maywood), 227, 881, 2002. van Breemen, R.B. et al.. Liquid chromatography-mass spectrometry of cis- and all-trans-lycopene in human serum and prostate tissue after dietary supplementation with tomato sauce, J. Agric. Food Chem., 50, 2214, 2002. 

Other dietary factors implicated in prostate cancer include retinol, carotenoids, lycopene, and vitamin D consumption.5,6 Retinol, or vitamin A, intake, especially in men older than age 70, is correlated with an increased risk of prostate cancer, whereas intake of its precursor, [3-carotene, has a protective or neutral effect. Lycopene, obtained primarily from tomatoes, decreases the risk of prostate cancer in small cohort studies. The antioxidant vitamin E also may decrease the risk of prostate cancer. Men who developed prostate cancer in one cohort study had lower levels of l,25(OH)2-vitamin D than matched controls, although a prospective study did not support this.2 Clearly, dietary risk factors require further evaluation, but because fat and vitamins are modifiable risk factors, dietary intervention may be promising in prostate cancer prevention. 

Other agents, including selenium, vitamin E, lycopene, green tea, nonsteriodal anti-inflammatory agents, isoflavones, and statins, are under investigsation for prostate cancer and show promise. Selenium is a naturally occurring trace element that is an essential nutrient in the human diet.8 However, none of these agents is currently recommended for routine use outside a clinical trial. 

Bowen, P, L. Chen, M. Stacewicz-Sapuntzakis et al. 2002. Tomato sauce supplementation and prostate cancer Lycopene accumulation and modulation of biomarkers of carcinogenesis. Exp Biol Med (Maywood) 227(10) 886-893. 

Hantz, H. L., L. F. Young, and K. R. Martin. 2005. Physiologically attainable concentrations of lycopene induce mitochondrial apoptosis in LNCaP human prostate cancer cells. Exp Biol Med (Maywood) 230(3) 171-179. 

Hwang, E. S. and P. E. Bowen. 2004. Cell cycle arrest and induction of apoptosis by lycopene in LNCaP human prostate cancer cells. J Med Food 7(3) 284-289. 

Siler, U., L. Barella, V. Spitzer et al. 2004. Lycopene and vitamin E interfere with autocrine/paracrine loops in the Dunning prostate cancer model. Faseb J 18(9) 1019-1021. 

Population studies associate tomato consumption with reduced risk to prostate cancer. The most positive associations have come from cohort studies performed before the prostate-specific antigen (PSA)-screening era, and these studies have suggested that the tomato/lycopene effect was the strongest for clinically relevant prostate cancers (Giovannucci 2007). Small human studies have shown in vivo antioxidant effects for tomato products but evidence for lycopene alone is weak (Chen et al. 2001, Porrini and Riso 2000, Riso et al. 2004, Zhao et al. 2006). Animal and tissue culture studies have been... 

In summary, lycopene must have some specific effect on unknown cellular processes that control the modulation of multiple pathways. General properties, such as antioxidation or pro-oxidation, are unlikely to explain these effects. Since the activation, silencing or loss of pathway control is different for each cell type and its degree of transformation, we do not have enough information to predict whether lycopene may be beneficial or detrimental under different circumstances in various prostate cell lines and in the different stages of prostate cancer. 

Barber, NJ, X Zhang, G Zhu et al. 2006. Lycopene inhibits DNA synthesis in primary prostate epithelial cells in vitro and its administration is associated with a reduced prostate-specific antigen velocity in a phase II clinical study. Prostate Cancer Prostatic Dis 9 407 -13. 

---