Regulation of SLUG gene expression by P53 in human mammary epithelial cells

SLUG is a member of a superfamily of zinc-finger transcriptional repressors. SLUG gene encodes a C2H2-type zinc finger transcription factor. The encoded protein binds to E2-box motif (5′-CACCTG-3′). Although many genes have the E2-box sequences at their promoters, only few proteins are experimentally shown to be regulated by SLUG. In human mammary epithelial cells, SLUG negatively regulates the E-cadherin, aromatase, PUMA, BRCA2, and cytokeratin 8 and 19 genes. Although SLUG plays a key role in the regulation of breast cell growth and proliferation, how SLUG gene expression is regulated in these cells is not studied. Since both SLUG and P53 down regulates BRCA2, we are verifying whether P53 up regulates SLUG in the human mammary epithelial cells. We generated constructs for the expression of firefly luciferase gene driven by the human SLUG gene promoter. We are testing the expression of luciferase from this promoter in the SLUG-negative MCF-7 (P53-positive) and MDA-MB-468 (P53-negative) cells as well as SLUG-positive but P53-negative BT549 and MDA-MB-231 cells. We are also evaluating the effect of lentiviral vector-mediated over expression or knock down of P53 in the P53-negative and P53-positive cells, respectively, on the activity of the SLUG promoter in these cells. This study will add to our knowledge of how the three proteins, P53, SLUG and BRCA2 are metabolically related in human breast cells and help us to understand the ontogeny of many sporadic breast cancer cases. Supported by the MMC/VICC cancer partnership grant #1U54CA091408-010003 from NCI and the DOD grant # DAMD17-00-1-0341 to GC.