The androgen receptor plays a critical role throughout the progression of prostate cancer and is an important drug target for this disease. While chromatin immunoprecipitation coupled with massively parallel sequencing (ChIP-Seq) is becoming an essential tool in studying transcription and chromatin modification factors, it has rarely been employed in the context of drug discovery. Here we report the first publicly available genome-wide and dose-dependent inhibition landscape of AR binding by drug-like small molecules including correlation with binding strength using ChIP-Seq. Integration of sequence analysis, transcriptome profiling, cell viability assays and in vivo tumor inhibition studies enabled us to establish a direct cistrome-activity relationship for two novel potent AR antagonists. By selectively occupying the strongest binding sites, AR signaling remains active even when low androgen levels are low, a scenario characteristic of first-line androgen ablation therapy. Coupled cistrome and transcriptome profiling upon small molecule antagonism led to the identification of not only key direct downstream effectors of AR but also their mode of regulation: unbiased pathway mapping revealed that AR is a key modulator of steroid metabolism by forming a tightly controlled feedback loop with other nuclear receptor family members. Furthermore, we found AR has an extensive role in negative gene regulation and estrogen (related) receptor likely mediates its function as a transcriptional repressor. In conclusion, our study provides a global and dynamic view of ARs regulatory program upon antagonism, which may serve as a molecular basis for deciphering and developing AR therapeutics.
Dose-dependent effects of small-molecule antagonists on the genomic landscape of androgen receptor binding.
Treatment
View SamplesGene expression and copy number variation arrays for parental GTL16 and GTL16 clones resistant to c-Met inhibitor.
A novel SND1-BRAF fusion confers resistance to c-Met inhibitor PF-04217903 in GTL16 cells through [corrected] MAPK activation.
Cell line
View SamplesA collection of genetically engineered mouse models (GEMM) of colorectal cancer (CRC) were created, and primary tumors from these GEMMs were analyzed.
Cross-species analysis of genetically engineered mouse models of MAPK-driven colorectal cancer identifies hallmarks of the human disease.
Specimen part
View SamplesNuclear pore complexes (NPCs) influence gene expression besides their established function in nuclear transport. The TREX-2 complex localizes to the NPC basket and affects gene-NPC interactions, transcription and mRNA export. How TREX-2 regulates the gene expression machinery is unknown. Here, we show that TREX-2 interacts with the Mediator complex, an essential regulator of RNA Polymerase (Pol) II. Structural and biochemical studies identify a conserved region on TREX-2, which directly binds the Mediator Med31/Med7N submodule. TREX-2 regulates assembly of Mediator with its Cdk8 kinase and is required for recruitment and site-specific phosphorylation of Pol II. Transcriptome and phenotypic profiling confirm that TREX-2 and Med31 are functionally interdependent. TREX-2 additionally uses its Mediator-interacting surface to regulate mRNA export suggesting a mechanism for coupling transcription initiation and early steps of mRNA processing at the Mediator level. In sum, we provide insight into how NPC-associated adaptor complexes can access the core transcription machinery. Overall design: RNAseq was performed from WT, sac3?, cdk8? and Sac3 R288D mutant cells. For each strain triplicates were analyzed. WT strain was sac3? transformed with pRS315 SAC3 WT
The Nuclear Pore-Associated TREX-2 Complex Employs Mediator to Regulate Gene Expression.
Subject
View SamplesMalignancies arising from mutation of tumor suppressor genes display an unexplained tissue proclivity. For example, tumor suppressor BAP1 encodes a ubiquitously expressed deubiquitinase for histone H2A but germline mutations predominantly cause uveal melanomas and mesotheliomas. We show that BAP1 inactivation causes apoptosis in mouse embryonic stem cells, fibroblasts, liver and pancreas, whereas melanocytes and mesothelial cells remain viable. E3 ligase RNF2, which silences genes by monoubiquitinating H2A, promoted apoptosis in BAP1-deficient cells by suppressing the pro-survival genes Bcl-2 and Mcl-1. Our data argue that BAP1 modulates gene expression by countering H2A ubiquitination, but its loss only promotes tumorigenesis in cells that do not engage an RNF2-dependent apoptotic program. We propose that intolerance of BAP1 loss, and perhaps the loss of other tumor suppressors, restricts the mutant tumor spectrum. Overall design: RNA was extracted from following genotypes - BAP1 wt (WT) and BAP1 knockout (BAP1 KO).
Intrinsic apoptosis shapes the tumor spectrum linked to inactivation of the deubiquitinase BAP1.
Specimen part, Subject
View SamplesThe prevailing dogma that approximately 50% of our genome is “junk” DNA composed of transposable elements and retroviral insertions has recently been challenged. It has become evident that our genome has taken advantage of these transposable elements and uses them as a source of DNA to generate novel genes, which subsequently allow the organism to evolve. This process is termed “domestication of transposable elements” and the majority of these genes have been found to be essential for the existence of the organism. One of these developmentally essential domesticated genes: Peg10 (paternally expressed gene 10), was derived from a Ty3/gyspy LTR retrotransposon, yet lost its ability to transpose due to mutational events during its domestication. Remarkably, Peg10 has successfully maintained its Gag and Pol-like domains for millions of years. Peg10 orthologues are expressed in eutherian mammals and are essential for placentogenesis. To address the functional mechanisms of Peg10 we studied it in Trophoblast Stem Cells (TSCs). We find that the Gag of Peg10 is fully active: it promotes budding of vesicles, akin to the viral counterpart that catalyzes the budding of viruses. TSCs, deleted for Peg10, fail to differentiate into placental lineages, underscoring a critical role in lineage specification. This paper discusses our efforts to characterize the contents of Peg10 vesicles and whether such vesicles regulate lineage specification. Overall design: RNA was extracted from following genotypes - wildtype TSCs (WT_TSC), Peg10 knockout TSCs (KO_TSC), wildtype TSCs differentiated in 20% oxygen (WT_TSC_diff), Peg10 knockout TSCs differentiated in 20% oxygen (KO_TSC_diff), wildtype TSCs differentiated in 2% oxygen (WT_diff_2O2),and Peg10 knockout TSCs differentiated in 2% oxygen (KO_diff_2O2). Cells are kept in the pluripotent state by growing them on CellStart/Fgf4/Heparin. The cells were differentiated in two different conditions: 20% oxygen and 2% oxygen. The samples were collected at 10th day following differentiation. Cells are harvested and RNA is isolated using the Qiagen RNeasy kit. RT-PCR was performed for several differentiation markers to validate the success of the assay.
The Gag protein PEG10 binds to RNA and regulates trophoblast stem cell lineage specification.
Specimen part, Subject
View Samples