| Autor: |
Pickholtz I; Laboratory of Genomic Applications, Department of Surgical Oncology, Sheba Medical Center, Ramat-Gan 52621, Israel. Sheba Cancer Research Center, Sheba Medical Center, Ramat-Gan 52621, Israel. Sackler school of Medicine, Tel Aviv University, Tel Aviv 69978, Israel., Saadyan S; Laboratory of Genomic Applications, Department of Surgical Oncology, Sheba Medical Center, Ramat-Gan 52621, Israel., Keshet GI; Sheba Cancer Research Center, Sheba Medical Center, Ramat-Gan 52621, Israel., Wang VS; Department of Human Science, Georgetown University Medical Center, Washington DC 20057, USA., Cohen R; Laboratory of Genomic Applications, Department of Surgical Oncology, Sheba Medical Center, Ramat-Gan 52621, Israel., Bouwman P; Division of Molecular Pathology and Cancer Genomic Center, The Netherland Cancer Institute, Amsterdam 1066, The Netherlands., Jonkers J; Division of Molecular Pathology and Cancer Genomic Center, The Netherland Cancer Institute, Amsterdam 1066, The Netherlands., Byers SW; Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, NW Washington DC 20057, USA., Papa MZ; Laboratory of Genomic Applications, Department of Surgical Oncology, Sheba Medical Center, Ramat-Gan 52621, Israel. Sackler school of Medicine, Tel Aviv University, Tel Aviv 69978, Israel., Yarden RI; Laboratory of Genomic Applications, Department of Surgical Oncology, Sheba Medical Center, Ramat-Gan 52621, Israel. Sheba Cancer Research Center, Sheba Medical Center, Ramat-Gan 52621, Israel. Department of Human Science, Georgetown University Medical Center, Washington DC 20057, USA. Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, NW Washington DC 20057, USA. |
| Abstrakt: |
Carriers of germline mutations in the BRCA1 gene have a significant increased lifetime risk for being diagnosed with breast cancer. The incomplete penetrance of BRCA1 suggests that environmental and/or genetic factors modify the risk and incidence among mutation carriers. Nutrition and particular micronutrients play a central role in modifying the phenotypic expression of a given genotype by regulating chromatin structure and gene expression. The active form of vitamin D, 1α,25-dihydroxyvitamin D3, is a potent inhibitor of breast cancer growth. Here we report that two non-calcemic analogues of 1α,25-dihydroxyvitamin D3, seocalcitol (EB1089) and QW-1624F2-2, collaborate with BRCA1 in mediating growth inhibition of breast cancer cells and breast cancer stem-like cells. EB1089 induces a G1/S phase growth arrest that coincides with induction of p21waf1 expression only in BRCA1-expressing cells. A complete knockdown of BRCA1 or p21waf1 renders the cells unresponsive to EB1089. Furthermore, we show that in the presence of ligand, BRCA1 associates with vitamin D receptor (VDR) and the complex co-occupies vitamin D responsive elements (VDRE) at the CDKN1A (p21waf1) promoter and enhances acetylation of histone H3 and H4 at these sites. Thus, BRCA1 expression is critical for mediating the biological impact of vitamin D3 in breast tumor cells. |
