MicroRNA expression profile of MCF-7 human breast cancer cells and the effect of green tea polyphenon-60.
ABSTRACT This study reports for the first time the microRNA expression profile of human breast cancer MCF-7 cells and the effect of green tea. Although hundreds of miRNAs have been identified in humans, only a small proportion (25.6%) of miRNAs are expressed in MCF-7 cells. Low concentration treatment with Polyphenon-60 significantly alters the miRNA expression profile in MCF-7 cells. Twenty three miRNAs have been identified with differential expression after a 48 h treatment with 10 μg/ml Polyphenon-60 (green tea extract). These miRNAs include miR-21 and miR-27 that were found to be down-regulated following treatment with green tea. These two miRNAs have previously been identified as being overexpressed in MCF-7 breast cancer cells, with miR-21 specifically implicated in down-regulating the tumor suppressor gene, tropomyosin-1. This data supports the hypothesis that Polyphenon-60-induced modification of the breast cancer miRNA expression profile contributes to the efficacy of green tea treatment. The resulting decrease in carcinogenesis is further supported by the altered miRNA regulation of potential oncogenes and tumor-suppressor genes.
- SourceAvailable from: Ghada H Elsayed[Show abstract] [Hide abstract]
ABSTRACT: Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer-related death among women worldwide. MicroRNAs (miRNAs) are naturally-occurring, non-coding small RNA molecules that can modulate protein coding-genes, which makes it contributing to nearly all the physiological and pathological processes. Progression of breast cancer and resistance to endocrine therapies has been attributed to the possibility of hormone-responsive miRNAs involved in the regulation of certain signaling pathways. Methodology This review introduces better understanding of miRNAs to provide promising advances for treatment. miRNAs have multiple targets, and they were found to regulate different signaling pathways; consequently it is important to characterize their mechanisms of action and their cellular targets in order to introduce miRNAs as novel and promising therapies. This review summarizes the molecular mechanisms of miRNAs in TGF-Beta signaling, apoptosis, metastasis, cell cycle, ER-signaling, and drug resistance. Finally, miRNAs will be introduced as promising molecules to be used in the fight against breast cancer and its developed drug resistance. Copyright © 2014. Published by Elsevier Inc.Clinical Biochemistry 12/2014; DOI:10.1016/j.clinbiochem.2014.12.013 · 2.23 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Cancer is the second leading cause of death in females. According to the American Cancer Society, there are 327,660 new cases in breast and gynecological cancers estimated in 2014, placing emphasis on the need for cancer prevention and new cancer treatment strategies. One important approach to cancer prevention involves phytochemicals, biologically active compounds derived from plants. A variety of studies on the impact of dietary compounds found in cruciferous vegetables, green tea and spices like curry and black pepper have revealed epigenetic changes in female cancers. Thus, an important emerging topic comprises epigenetic changes due to the modulation of noncoding RNA levels. Since it has been shown that noncoding RNAs such as microRNAs and long noncoding RNAs are aberrantly expressed in cancer and furthermore are linked to distinct cancer phenotypes, understanding the effects of dietary compounds and supplements on the epigenetic modulator noncoding RNA is of great interest. This article reviews the current findings on nutrition-induced changes in breast and gynecological cancers at the noncoding RNA level.05/2015; 2. DOI:10.3389/fnut.2015.00016
- [Show abstract] [Hide abstract]
ABSTRACT: MicroRNA (miRNA) profiles obtained for extracellular vesicles (EVs) derived from MCF7 and MCF10A cells were analyzed to identify unique characteristics that distinguish their cell sources. One characteristic common to the miRNA profiles of MCF7 EVs and their parent cells is high abundances of miR-21, let-7a, miR-100, and miR-125b, and the low levels of miR-205. A second characteristic is the high abundance of "microRNA-like" transfer RNA (tRNA) fragments, which is unique to the MCF7 EVs, and is not found in comparing the cellular profiles. We also examined correlations in the MCF7 cellular expression levels of these five miRNAs and two tRNA-derived miRNAs, miR-720 and miR-1274b, and compared them to correlations in the MCF7 EV levels. We find that correlations in the cellular expression levels of miR-125b, miR-100, and let-7a are mirrored in the EVs. In contrast, correlations in tRNA-derived miRNA levels are found only in the EVs. The findings suggest that EV miRNA clusters can be defined based on functional miRNA interactions related to correlated cellular expression levels or purely physical miRNA interactions - e.g., aggregation due to comparable binding affinities to common targets. Implications: Recognizing that tRNAs are over-expressed in proliferative diseases, such as cancer, our results point to using high levels of tRNA-derived small RNA fragments in combination with known miRNA signatures of cancer tumors to distinguish tumor-derived EVs in circulation from EVs derived by other cell sources. Such biomarkers would be unique to the EVs where high abundances of tRNA fragments are amplified with respect to their cellular levels. Copyright © 2015, American Association for Cancer Research.Molecular Cancer Research 02/2015; 13(5). DOI:10.1158/1541-7786.MCR-14-0533 · 4.50 Impact Factor