The Possibility of Preventive and Therapeutic Use of Green Tea Catechins in Prostate Cancer.

BACKGROUND: Prostate cancer is one of the most frequent types of cancer. Despite the existence of various treatment strategies, treatment of prostate cancer still presents serious difficulties (especially in advanced stages). Polyphenols have been extensively assessed in terms of their potential use for prostate cancer treatment and prevention. Catechins are among the most well-known polyphenols in this respect. OBJECTIVE: In this review, we summarize clinical study results concerning catechin applications with regard to prostate cancer treatment and prevention. We discuss some of the main mechanisms of the anticarcinogenic action of catechins. CONCLUSION: The main mechanisms of the anticarcinogenic action of catechins are subdivided into two major types: (i) direct action on cancer cells and (ii) indirect effect based on catechins's impact on the microenvironment of cancer cells, particularly in relation to the immune system. At this level catechins might reduce tumor-associated inflammation and immune tolerance.

Effect of progesterone and its synthetic analogues on the activity of mitochondrial permeability transition pore in isolated rat liver mitochondria.

The influence of progesterone and its synthetic analogues on the induction of the Ca(2+)-dependent mitochondrial permeability transition pore (MPTP) has been studied. The novel synthetic analogue of progesterone 17a-acetoxy-3b-butanoyloxy-6-methyl-pregna-4,6-diene-20-on (buterol) was compared with progesterone and medroxyprogesterone acetate (MPA). It was found that progesterone and buterol have opposite effects on the induction of MPTP opening by calcium ions. By contrast to progesterone, which decreased the calcium ion concentration necessary for pore opening, and MPA, which also, although at a lesser extent, activated the pore induction, buterol at a concentration of 20-100 microM blocked the pore opening and increased the calcium retention capacity of mitochondria more than twofold. The action of buterol is specific to the pore since it did not affect the respiration, whereas progesterone completely inhibited NAD-dependent respiration. MPA acted similar to progesterone but less effectively. The inhibitory effect of buterol was eliminated in the presence of carboxyatractyloside, which selectively binds the thiol groups of adenylate translocase and prevents the adenine nucleotide binding. These data indicate that buterol interacts with thiol groups, which explains its inhibitory effect not only on the mitochondrial pore but also on the transport system of xenobiotics in tumor cells in which buterol reduces the multidrug resistance.