This study focused on the expression and regulation of BRCA1 in breast cancer cell lines compared to normal breast. BRCA1 transcript levels were assessed by real time quantitative polymerase chain reaction (RT-qPCR) in the cancer cell lines. Our data show overexpression of BRCA1 mRNA level in all the studied breast cancer cell lines: MCF-7, T47D, MDA-MB-231 and MDA-MB-468 along with Jurkat, leukemia T-lymphocyte, the positive control, relative to normal breast tissue. To investigate whether a positive or negative correlation exists between BRCA1 and the transcription factor E2F6, three different si-RNA specific for E2F6 were used to transfect the normal and cancerous breast cell lines. Interestingly, strong negative relationship was found between BRCA1 and E2F6, in which depletion of E2F6 in MCF-10A, the normal breast cell line, resulted in more than four-fold increased expression of BRCA1 transcript level. On the other hand, our findings suggest that E2F6 might lost control on BRCA1 in breast cancer cells. E2F6 knockdown by either of two specific siRNA (i.e. si-E2F6#1 or si- E2F6#2) had no influence on the BRCA1 expression in MCF-7 cells. Although, transfecting these cells with si-E2F6#3 showed overexpression of BRCA1 compared to cells transfected with scrambled negative control.
University of Baghdad
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