| Breast cancer is the most commonly diagnosed type of cancer in females. Triple Negative Breast Cancer (TNBC) is a subtype of breast cancer that lacks the estrogen receptor (ER) and progesterone receptor (PR), and lacks human epidermal growth factor receptor 2 (HER2) amplification. The treatment of TNBC has been made challenging because of its heterogeneity, the absence of well-defined molecular targets, and the high p53 mutation rates of TNBC cells. This aggressive breast cancer phenotype is due to its high mitotic index and high metastatic potential, and may be due to the fact that up to 80% of TNBC has a mutation in the p53 tumor suppressor gene. The p53 tumor suppressor gene signaling pathway can be mediated by microRNAs (miRNAs), which are short sequences of RNA (∼22nt) that target protein coding mRNA and mark them for degradation. Characterization of the miRNA profiles in TNBC cells compared to luminal and normal breast cell lines may provide potential targets in treating TNBC. The objective of this study was to investigate the response of miR-21 and miR-34a expression in breast cancer cells in response to genotoxic stress caused by exposure to chemotherapeutics Staurosporine, Doxorubicin, and ActinomycinD. In this study, real-time PCR was performed on TNBC breast cancer cell lines (HCC1806 and HCC70) and a luminal B control cell line, HCC1500. The expression levels of miRNAs speculated to play a role in the p53 tumor suppressor gene signaling pathway were compared between breast cancer cell lines HCC1806, HCC70, and HCC1500. The miRNAs miR-34a and miR-21 were examined and displayed differential expression levels between the breast cancer cell lines, thereby implicating them as potential biomarkers for TNBC and potential drug treatment targets. These miRNAs can be studied further to determine their role in mediating the p53 tumor suppressor gene signaling pathway in these cells for their potential use in the diagnosis, prognosis, and treatment of TNBC. |
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