Modification of miRNA Expression through plant extracts and compounds against breast cancer: Mechanism and translational significance.

Cancer is hyper-proliferative, multi-factorial and multi-step, heterogeneous group of molecular disorders. It is the second most reported disease after heart diseases. Breast carcinoma is the foremost death causing disease in female population worldwide. Cancer can be controlled by regulating the gene expression. Current therapeutic options are associated with severe side effects and are expensive for the people living in under-developed countries. Plant derived substances have potential application against different diseases like cancer, inflammation and viral infections.The mechanism of action of the medicinal plants is largely unknown. Targeting gene network and miRNA using medicinal plants could help in improving the therapeutic options against cancer.The literature from 135 articles was reviewed by using PubMed, google scholar, Science direct to find out the plants and plant-based compounds against breast cancer and also the studies reporting their mechanistic route of action both at coding and noncoding RNA levels.Natural products act as selective inhibitors of the cancerous cells by targeting oncogenes and tumor suppressor genes or altering miRNA expression. Natural compounds like EGCG from tea, Genistein from fava beans, curcumin from turmeric, DIM found in cruciferous, Resveratrol a polyphenol and Quercetin a flavonoid is found in various plants have been studied for their anticancer activity. The EGCG was found to inhibit proliferative activity by modulating miR-16 and miR-21. Similarly, DIM was found to down regulate miR-92a which results to modulate NFkB and stops cancer development. Another plant-based compound Glyceollins found to upregulate miR-181c and miR-181d having role in tumor suppression. It also found to regulate miR-22, 29b and c, miR-30d, 34a and 195. Quercetin having anti-cancer activity induce the apoptosis through regulating miR-16, 26b, 34a, let-7g, 125a and miR-605 and reduce the miRNA expression like miR-146a/b, 503 and 194 which are involved in metastasis.Targeting miRNA expression using natural plant extracts can have a reverse effect on cell proliferation; turning on and off tumor-inducing and suppressing genes. It can be efficiently adopted as an adjuvant with the conventional form of therapies to increase their efficacy against cancer progression.