Restoration of Altered Oncogenic and Tumor Suppressor microRNA Expression in Breast Cancer and Colorectal Cancer Cell using Epicatechin.

Background: MicroRNAs (miRNA) are small non-coding RNAs that regulate the function of mRNA post-transcriptionally in a tissue-specific manner. miRNA expressions are heavily dysregulated in human cancer cells through various mechanisms, including epigenetic changes, karyotype abnormalities, and miRNA biogenesis defects. miRNAs may act as either oncogenes or tumor suppressors under different conditions. Epicatechin is a natural compound found in green tea which possesses antioxidant and antitumor properties.

Objective: The objective of this study is to investigate the effect of epicatechin treatment on the expression level of several oncogenic and tumor suppressor miRNAs in breast and colorectal cancer cell lines (MCF7 and HT-29) and identify its mechanism of action.

Methods: The MCF-7 and HT29 cells were treated with epicatechin for 24 hours and untreated cells were considered control cultures. miRNA was isolated and qRT-PCR was used to measure the expression profile changes of different oncogenic and tumor suppressor miRNAs. Furthermore, the mRNA expression profile was also screened at different concentrations of epicatechin.

Results: Our results showed several-fold changes in miRNAs expression level, which is cell line specific. Also, epicatechin at different concentrations induces biphasic changes in mRNA expression levels in both cell lines.

Conclusion: Our findings first time demonstrated that epicatechin can reverse the expression of these miRNAs and may trigger the cytostatic effect at a lower concentration.