Epigenetic alterations contribute to all stages of tumor progression and it is well recognized that aberrant DNA methylation and histone hypoacetylation of growth control genes and tumor suppressor genes directly contribute to malignancy. Because epigenetic changes are reversible, these alterations represent attractive targets for promising new anticancer agents and this property has been exploited recently for new therapies. While recent progress has lead to the FDA approval of the first two """"""""epigenetic therapies"""""""" the mechanistic basis for their efficacy is poorly understood. This proposal will explore entirely new links between a relatively unexplored class of deacetylases (the sirtuins) and proteins that bind to methylated DNA (methyl-CpG binding proteins) in gene silencing. These advances could help explain why some solid tumors are refractory to the current epigenetic therapies and provide a more complete mechanism by which tumor suppressor genes (TSGs) become heritably silenced. Elucidating the molecular basis for this epigenetic silencing of growth control genes and TSGs is important for identifying novel anticancer therapies and we propose to do the following:
Specific Aim 1 - Determine the role of methyl-CpG binding proteins in targeting SIRT1 to endogenous hypermethylated gene promoters.
Specific Aim 2 - Determine the contribution of methyl-CpG binding proteins and SIRT1 in regulating chromatin structure at silenced growth control and tumor suppressor genes.
Specific Aim 3 - Determine the functional significance of MeCP2 acetylation and deacetylation by SIRT1.
Because multiple HDAC inhibitors are in various phases of clinical trials, it is important to understand how deacetylases contribute to tumorigenesis, and we have identified a novel role for the sirtuin family of deacetylases in tumor suppressor gene silencing.
|Dykes, Samantha S; Gray, Alana L; Coleman, David T et al. (2016) The Arf-like GTPase Arl8b is essential for three-dimensional invasive growth of prostate cancer in vitro and xenograft formation and growth in vivo. Oncotarget 7:31037-52|
|Manna, Pulak R; Stetson, Cloyce L; Slominski, Andrzej T et al. (2016) Role of the steroidogenic acute regulatory protein in health and disease. Endocrine 51:7-21|
|Saxena, M; Dykes, S S; Malyarchuk, S et al. (2015) The sirtuins promote Dishevelled-1 scaffolding of TIAM1, Rac activation and cell migration. Oncogene 34:188-98|
|Pandey, Somnath; Simmons Jr, Glenn E; Malyarchuk, Svitlana et al. (2015) A novel MeCP2 acetylation site regulates interaction with ATRX and HDAC1. Genes Cancer 6:408-21|
|Manna, Pulak R; Stetson, Cloyce L; Daugherty, Carol et al. (2015) Up-regulation of steroid biosynthesis by retinoid signaling: Implications for aging. Mech Ageing Dev 150:74-82|
|Simmons Jr, Glenn E; Pruitt, Wendy M; Pruitt, Kevin (2015) Diverse roles of SIRT1 in cancer biology and lipid metabolism. Int J Mol Sci 16:950-65|
|Manna, Pulak R; Sennoune, Souad R; Martinez-Zaguilan, Raul et al. (2015) Regulation of retinoid mediated cholesterol efflux involves liver X receptor activation in mouse macrophages. Biochem Biophys Res Commun 464:312-7|
|Soung, Young Hwa; Pruitt, Kevin; Chung, Jun (2014) Epigenetic silencing of ARRDC3 expression in basal-like breast cancer cells. Sci Rep 4:3846|
|Simmons Jr, Glenn E; Pandey, Somnath; Nedeljkovic-Kurepa, Ana et al. (2014) Frizzled 7 expression is positively regulated by SIRT1 and ?-catenin in breast cancer cells. PLoS One 9:e98861|
|Holloway, Kimberly R; Barbieri, Andreia; Malyarchuk, Svitlana et al. (2013) SIRT1 positively regulates breast cancer associated human aromatase (CYP19A1) expression. Mol Endocrinol 27:480-90|