ANTI-CANCER MECHANISM OF PLANT FACTORS AS miRNA REGULATING AGENTS

Background: miRNAs are small RNA molecules of 17–25 nucleotides that do not encode a protein. They negatively regulate gene expression through binding to target mRNAs leading to mRNA degradation or translation inhibition. Aberrant miRNA expression is implicated in almost all human cancers. miRNAs involved in carcinogenesis are classified into oncogenic miRNAs (oncomiRs) and tumor suppressor miRNAs (tumor suppressor miRs). Therefore, they have the potential to be used as biomarkers, as well as therapeutic targets for cancer. Otherwise, many studies have shown that several natural products such as teas, garlic, soy products, herbs, grapes and cruciferous vegetables can act for cancer prevention and treatment. Regarding to their underlying anticancer mechanism, it has been shown that bioactive compounds found in these plants has the ability to alter the aberrant expression of different miRNAs. Method: this abstract summarizes the recent finding regarding the bioactive natural agents found in plants that has been demonstrated in several studies to could modify the expression of different miRNA in human cancers. Results: The expression of different miRNAs could be altered in human cancers via active components exist in our diet which is as following: Curcumin in turmeric can alter the expression of miR-15a, miR-16, miR-21, miR-22, miR-26, miR-34a, miR-101, miR-146, miR-186, miR-192-5p/215,miR-199, miR-200, miR-203, let-7. Epigallocatechin-3-gallate (EGCG) in green tea could affect on miR-16, miR-21, miR-27, miR- 330 expression. Resveratrol found in grapes, berries, plum and peanuts could alter the expression of miR-17, miR-21,miR-25, miR-29a, mir-137, miR-663, miR-773 mir-196a and miR-520. Quercetin from soybeans can affect on miR-21 and miR-27 expression. Genistein found in soybeans can also alter miR-34a, miR-21, miR-200 and miR-27a expression. In addition, Isothiocyanates found in broccoli, cabbage, brussels sprouts, watercress, kale and cauliflower can alter the expression of miR-17, miR-20a, miR-27a and miR-17-5p. Discussion: MicroRNAs play critical roles in cell physiological processes, and in the pathogenic mechanisms of tumor development. Aberrant microRNAs expression is observed in diverse human cancers, so many cancer treatment strategies focuses on miRNA expression. The ability of mentioned dietary active components to reverse miRNA deregulation in cancer cells and their availability makes them as new promising therapeutic agents that can be used directly or in combination with other chemotherapy drugs for cancer treatment and prevention.