Castrate-resistant prostate cancer (CRPC) is poorly characterized and heterogeneous and while the androgen receptor (AR) is of singular importance in early prostate cancer, other factors such as c-Myc and the E2F family also play a role in later stage disease. Hes6 is a transcription co-factor that has been associated with neurogenesis during gastrulation, a neuroendocrine phenotype in the prostate and metastasis in breast cancer but its role in prostate cancer remains uncertain. Here we show that Hes6 is controlled by c-Myc and AR and drives castration resistance in prostate cancer. Hes6 activates a cell-cycle enhancing transcriptional network that maintains tumour growth and nuclear AR localization in castrate conditions. We show aphysical interaction between E2F1 and both Hes6 and AR, and suggest a co-dependency of these transcription factors in castration-resistance. In the clinical setting, we have uncovered a Hes6-associated signature that predicts poor outcome in prostate cancer, which can be pharmacologically targeted. We have therefore shown for the first time the critical role of Hes6 in the development of CRPC and identified its potential in patient specific therapeutic strategies.
HES6 drives a critical AR transcriptional programme to induce castration-resistant prostate cancer through activation of an E2F1-mediated cell cycle network.
Specimen part, Disease, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
No associated publication
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
No associated publication
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
FOXA1 is a key determinant of estrogen receptor function and endocrine response.
Cell line, Treatment
View SamplesTo identify which genes were regulated by mRNA helicase activity, the effect of eIF4A1 knockdown on the MCF7 cell transcriptome and translatome was determined. eIF4A1-dependent mRNAs were highly enriched for several classes of genes with oncogenic potential, which leads to a model whereby dysregulation of mRNA unwinding contribues to the malignant phenotype in breast cancer cells via preferential translation of a subset of genes.
No associated publication
Cell line
View SamplesLong noncoding RNAs (lncRNAs) regulate gene expression via their RNA product or through transcriptional interference, yet a strategy to differentiate these two processes is missing. We employed siRNAs to specifically target GNG12-AS1, a lncRNA overlapping the tumour suppressor DIRAS3, transcriptionally or post-transcriptionally. lncRNA transcriptional silencing by siRNA was mediated by Argounate 2 and led to the upregulation of DIRAS3 transcription through switch in RNA polymerase II binding and active histone marks. Conversely, post-transcriptional silencing of GNG12-AS1 had no effect on DIRAS3 expression. Thus, our findings reveal how RNAi machinery can be used to decouple the process and products of lncRNA transcription.
No associated publication
Specimen part, Cell line
View SamplesLong noncoding RNAs (lncRNAs) regulate gene expression via their RNA product or through transcriptional interference, yet a strategy to differentiate these two processes is missing. We employed siRNAs to specifically target GNG12-AS1, a lncRNA overlapping the tumour suppressor DIRAS3, transcriptionally or post-transcriptionally. lncRNA transcriptional silencing by siRNA was mediated by Argounate 2 and led to the upregulation of DIRAS3 transcription through switch in RNA polymerase II binding and active histone marks. Conversely, post-transcriptional silencing of GNG12-AS1 had no effect on DIRAS3 expression. Thus, our findings reveal how RNAi machinery can be used to decouple the process and products of lncRNA transcription.
No associated publication
Specimen part, Cell line
View SamplesMethods for identifying protein-protein interactions have mostly been limited to tagged exogenous expression approaches. We now establish a rapid, robust and comprehensive method for finding interacting proteins using endogenous proteins from limited cell numbers. We apply this approach called Rapid IP-Mass Spectrometry of Endogenous proteins (RIME) to identify ER, FoxA1 and E2F4 interacting proteins in breast cancer cells. From small numbers of starting cells, we find a comprehensive collection of known ER, FoxA1 and E2F4 targets, plus a number of novel unexpected interactors. One of the most ER (and FoxA1) associated interactors is GREB1, an estrogen induced gene with almost no known function. We apply RIME, in parallel with ER ChIP-seq, to identify ER protein interactors and ER binding events from solid tumor xenografts, resulting in the validation of the ER-GREB1 interactions. Furthermore, we establish a method for identifying endogenous interacting proteins from solid primary breast cancer samples, whih we apply to validate ER interactions with GREB1 and additional co-factors. Mechanistically, we show that GREB1 is recruited with ER to the chromatin where it functions as an essential estrogen-mediated regulatory factor required for effective ER transcriptional activity. Our novel approach enables, for the first time, the ability for discovery and validation of protein-protein interactions in whole tissue and solid tumors, revealing significant insight into ER regulatory factors.
Endogenous purification reveals GREB1 as a key estrogen receptor regulatory factor.
Cell line, Treatment
View SamplesAll patients with suspected ovarian cancer (Raised CA 125 and a complex pelvic mass in a perimenopausal woman) were radiologically staged using CT scan and a chest x-ray. Patients with evidence of intra-abdominal metastasis and/or malignant pleural effusion were approached for entry to the study. Tissue biopsy was obtained either under radiological control (core needle biopsy) or via laparoscopic surgery (punch biopsy). Patients with histologicaly confirmed epithelial ovarian cancer were randomized to receive either three cycles of carboplatin (AUC 7) or paclitaxel (175 mg/m2).
The extracellular matrix protein TGFBI induces microtubule stabilization and sensitizes ovarian cancers to paclitaxel.
No sample metadata fields
View SamplesEstrogen Receptor-a (ER) is the key feature in the majority of breast cancers and ER binding to the genome correlates with the Forkhead protein FOXA1 (HNF3a), but mechanistic insight is lacking. We now show that FOXA1 is the defining factor that governs differential ER-chromatin interactions. We show that almost all ER-chromatin interactions and gene expression changes are dependent on the presence of FOXA1 and that FOXA1 dictates genome-wide chromatin accessibility. Furthermore, we show that CTCF is an upstream negative regulator of FOXA1-chromatin interactions. In ER responsive breast cancer cells, the dependency on FOXA1 for tamoxifen-ER activity is absolute and in tamoxifen resistant cells, ER binding occurs independently of ligand, but in a FOXA1 dependent manner. Importantly, expression of FOXA1 in non-breast cancer cells is sufficient to alter ER binding and response to endocrine treatment. As such, FOXA1 is the primary determinant that regulates estrogen-ER activity and endocrine response in breast cancer cells and is sufficient to program ER functionality in non-breast cancer contexts.
FOXA1 is a key determinant of estrogen receptor function and endocrine response.
Cell line, Treatment
View Samples