ABSTRACT
There is an increasing focus on chemoprevention in diseases with rising incidence, long latency or slow progression, such as prostate cancer and hyperplasia.
Lycopene is a potent antioxidant. Epidemiological studies show that increased lycopene consumption reduces the risk of prostate cancer and it also holds some promise in treating male infertility, chiefly by countering oxidative damage to DNA. Lycopene also has activities independent of antioxidant function. It can improve gap-junction communication, induce apoptosis, influence angiogenesis and suppress cell proliferation through influences on cytokines.
Prostasomes are microparticles secreted by prostatic epithelial cells into semen and are also liberated from malignant prostatic tissue. They are multilamellar membranous lipoprotein vesicles. Proteomics reveal over 130 associated proteins and their lipid composition displays abundance of cholesterol and sphingomyelin. Prostasomes are facilitators of male fertility; however, their role in prostate cancer remains unresolved.
Lycopene is found in abundance in the prostate gland. From their structure, prostasomes are candidate vehicles for transporting lipophilic compounds such 202as lycopene, offering a relative degree of shielding to this bioactive molecule against untimely degradation in transit. In return, lycopene offers protection to these lipoperoxidation-prone moieties, thereby also allowing them to reach their destination unscathed. We have experimentally examined this mutually beneficial association. The simplest model demonstrates prostasomes incorporating exogenous lycopene in a cell-free system. Further studies show lycopene to be taken up and subsequently expelled in microparticles by cells, suggesting that dietary lycopene may enter prostatic cells, to be exported as prostasomal lycopene. Human dietary supplementation studies with lycopene also support this hypothesis.
Lycopene remains a promising chemopreventive agent in human prostate cancer and has potential in the management of benign prostatic hyperplasia and male infertility. While exact mechanisms remain unclear, we present evidence that prostasomes facilitate trafficking of lycopene into semen or the stroma of prostate tissues, where it may impinge on fertility and prostatic pathologies.
