Project description:The project is directed to the development of selective glucocorticoid receptor agonists for anticancer therapy. Glucocorticoids (GC) are widely used in treatment of many types of cancer due to its ability to induce apoptosis in malignant cells (in blood cancer therapy) and to prevent nausea and emesis (in the chemotherapy of solid tumors). However, severe dose-limiting side effects occur, including osteoporosis, muscle wasting, diabetes and other metabolic complications. Both beneficial and harmful effects of glucocorticoids are due to selective activation or repression of particular genes by glucocorticoid receptor (GR). GR regulates gene expression via transactivation that requires GR homodimer binding to gene promoters and transrepression mediated via negative interaction between GR and other transcription factors as well as binding with negative glucocorticoid response elements (nGRE) in genes. GR transactivation is linked to metabolic side effects, while GR transrepression underlies glucocorticoid therapeutic action. Novel selective GR agonist Compound A (CpdA) prevents GR dimerization and transactivation, specifically activates GR transrepression, and has fewer side effects compared to glucocorticoids. Here we compare the gene expression profiles in prostate cancer cells treated with glucocorticoid Dexamethasone (Dex) or CpdA
Project description:Glucocorticoids (GC) have been widely used as coadjuvants in the treatment of solid tumors, but GC treatment may be associated with poor pharmacotherapeutic response and/or prognosis. The genomic action of GC in these tumors is largely unknown. Here we find that dexamethasone (Dex, a synthetic GC) regulated genes in triple-negative breast cancer (TNBC) cells are associated with drug resistance. Importantly, these GC-regulated genes are aberrantly expressed in TNBC patients and associated with unfavorable clinical outcomes. Interestingly, in TNBC cells, Compound A (CpdA, a selective GR modulator) only regulates a small number of genes not involved in carcinogenesis and therapy resistance. Mechanistic studies using a ChIP-exo approach reveal that Dex- but not CpdA-liganded glucocorticoid receptor (GR) binds to a single glucocorticoid response element (GRE), which drives the expression of pro-tumorigenic genes. Our data suggest that development of safe coadjuvant therapy should consider the distinct genomic function between Dex- and CpdA-liganded GR. To study GR-regulated genes and define GRE in human genome, RNA-seq and GR ChIP-exo are performed in MDA-MB-231 cells before/after dex and CpdA stimulation. Each experiment includes two replicates.