Abstract B59: Polycomb group ring finger protein plays a role in gamma ionizing radiation-induced DNA damage response in MCF7 cell line.

Abstract

Abstract Polycomb group (PcG) gene product is a family of proteins that were accumulated with complexes in nuclear and plays an important role in development and maintaining stem cell population of hematopoietic and neuronal cell lineages. PcG complexes can regulate the transcriptional activity of many genes by epigenetic silencing involved in embryogenesis. Recent reports showed the overexpressions of PcG proteins were correlated with the severity of many cancers. To investigate the underlying mechanisms of PcG ubiquitin ligase (PCGF1-6) on DNA damage response after exposure to gamma ionizing radiation, we generated the stable knockdown MCF7 breast cancer cell lines capable of silencing each of PcG ubiquitin ligase genes. Cell survival and proliferation analysis in stable PcG ubiquitin ligase knockdown MCF7 cell lines was compared to the analysis in control MCF7 cell lines after treatment of gamma ionizing radiation using MTT and colony forming assay. Furthermore, we found that loss of several PcG ubiquitin ligases sensitizes MCF7 cell lines to gamma ionizing radiation-mediated growth inhibition. We further demonstrate that several PCGF PcG ubiquitin ligases are localized at γ-H2AX foci after treatment of gamma ionizing radiation. These results demonstrate that PCGF family can coordinately regulate the cell resistance mechanism in DNA damage response. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B59.