Targeting microRNAs: Molecular basis of cancer prevention

Abstract

Recent studies have shown that the alterations in the expression of miRNAs play critical roles in the processes of carcinogenesis and cancer progression. During the process of carcinogenesis, gene mutation and epigenetic aberration together with the exposure of environmental factors such as infection, ultraviolet light, irradiation, and environmental toxicants could change the expression level of miRNAs, resulting in the alterations in gene expression and cellular signal transductions. The aberrant expression of miRNAs initiates carcinogenesis and subsequently promotes the progression of cancers. Therefore, targeting the altered miRNAs may be a new approach for cancer prevention and treatment. Interestingly, dietary agents (natural agents) collectively known as nutraceuticals have been found to modulate and normalize the expression of miRNAs. Thus, the non-toxic dietary natural agents such as isoflavone genistein, curcumin, resveratrol, I3C, DIM, vitamins, etc. may have effects on cancer prevention and treatment. The in vitro and in vivo studies have provided the evidences showing that these agents could up-regulate tumor suppressive miRNAs and down-regulate oncogenic miRNAs, resulting in the suppression of cancer formation and progression. Hence, these agents could prevent the occurrence of cancer and may also inhibit tumor progression. Moreover, treatment with these non-toxic agents together with chemotherapeutics may be a novel approach for cancer therapy.