Regulation of MicroRNAs by Natural Products and Bioactive Compounds Obtained From Common Medicinal Plants: Novel Strategy in Cancer Therapy

MicroRNAs (miRNAs) are highly conserved non-protein coding small RNAs, known to contribute to the epigenetic regulation process in various cancer cells, including the regulation of progression, proliferation and metastasis of cancer cells, differentiation of the cells and process of apoptosis. In addition to, they are crucial for the regulation of cancer stem cells, and management the process of epithelial to mesenchymal transition of cancer cells, implicating in the cancer cells. Further to this, their roles are changeable depending on biological processes, for example miR-17, miR-20a, miR-19b-1, miR-18a, miR-19a, miR-92-1, miR-21, and miR-155 may have critical roles as oncogenic miRNAs (oncomiRs), while miR-15, miR-16, let-7, miR-34, miR-48, miR-84, miR-241 may have anticancer activities as tumor suppressor miRNAs. Therefore, the regulation of miRNAs levels by active natural compounds and/or products could be a promising strategy for cancer treatment, especially in order to inhibit cancer progression and proliferation, prevent metastasis, control the process of transition of cancer cells, and overcome chemotherapeutic resistance by increasing drug sensitivity as well. Recent studies and clinical trials which are aimed to find novel targets for the treatment of cancer, have emphasized the importance of the consumption of natural anticancer agents-rich diet. In the current review, we aimed to provide overview anticancer effects of natural compounds and/or products, isolated from medicinal plants, on miRNAs which are closely related to cancer progression and metastasis.