Epigenetic Changes Induced by Green Tea Catechins a re Associated with Prostate Cancer

Prostate cancer is one of the most difficult cancers to treat especially when it becomes hormone resistant such as castrate resistant prostate cancer (CRPC) and subsequent metastatic CRPC. Apart from the genetic alterations in prostate cancer, epigenetic modifications also play an important role in the development and neoplastic progression of this disease. These include DNA methylation, histone modifications, and non-coding microRNAs. miRNAs are a novel class of small endogenous single-stranded non-coding RNAs of 19-25 nucleotides in length that typically silence gene expression. Considering the reversibility of epigenetic alterations in early carcinogenesis process, reversion (correction) of these modifications by green tea catechins could be a promising strategy for cancer chemoprevention and therapy. Recent evidence suggests that green tea catechins such as epigallocatechin gallate (EGCG) not only act as epigenetic modulators but can also modify miRNA expression and their target mRNAs, consistently contributing to the inhibition of prostate carcinogenesis. Various studies also indicate that several green tea polyphenols (GTPs) exert synergistic effects with other cancer chemotherapeutic agents. Therefore, the use of appropriate combinations of green tea catechins with the existing chemotherapeutics will lead to a reduction in side effects without decreasing the chemotherapeutic effects. This review will summarize the key results from recent studies detailing the effects of green tea catechins such as EGCG on epigenetic alterations and miRNA expression in prostate cancer.