Androgen receptor (AR) is the major therapeutic target in aggressive prostate cancer. However, targeting AR alone can result in drug resistance and disease recurrence. Therefore, simultaneous targeting of multiple pathways could in principle be an effective new approach to treating prostate cancer. Here we provide proof-of-concept that a small molecule inhibitor of nuclear ß-catenin activity (called C3) can inhibit both the AR and ß-catenin signaling pathways that are often misregulated in prostate cancer. Treatment with C3 ablated prostate cancer cell growth by disruption of both ß-catenin/TCF and ß-catenin/AR protein interaction, reflecting the fact that TCF and AR have overlapping binding sites on ß-catenin. Given that AR interacts with, and is transcriptionally regulated by ß-catenin, C3 treatment also resulted in decreased occupancy of ß-catenin on the AR promoter and diminished AR and AR/ß-catenin target gene expression. Interestingly, C3 treatment resulted in decreased AR binding to target genes accompanied by decreased recruitment of an AR and ß-catenin cofactor, CARM1, providing new insight into the unrecognized function of ß-catenin in prostate cancer. Importantly, C3 inhibited tumor growth in an in vivo xenograft model, and blocked renewal of bicalutamide-resistant sphere forming cells, indicating the therapeutic potential of this approach. Overall design: Compare and contrast the expression profile of prostate cancer cells treated with a Wnt inhibitor (C3) with respect to ß-catenin and AR knockdown (all samples in duplicates).
Inhibition of androgen receptor and β-catenin activity in prostate cancer.
Disease, Subject
View SamplesThe androgen receptor (AR) is a mediator of both androgen-dependent and castration- resistant prostate cancers. Identification of cellular factors affecting AR transcriptional activity could in principle yield new targets that reduce AR activity and combat prostate cancer, yet a comprehensive analysis of the genes required for AR-dependent transcriptional activity has not been determined. Using an unbiased genetic approach that takes advantage of the evolutionary conservation of AR signaling, we have conducted a genome-wide RNAi screen in Drosophila cells for genes required for AR transcriptional activity and applied the results to human prostate cancer cells. We identified 45 AR-regulators, which include known pathway components and genes with functions not previously linked to AR regulation, such as HIPK2 (a protein kinase) and MED19 (a subunit of the Mediator complex). Depletion of HIPK2 and MED19 in human prostate cancer cells decreased AR target gene expression and, importantly, reduced the proliferation of androgen-dependent and castration-resistant prostate cancer cells. We also systematically analyzed additional Mediator subunits and uncovered a small subset of Mediator subunits that interpret AR signaling and affect AR-dependent transcription and prostate cancer cell proliferation. Importantly, targeting of HIPK2 by an FDA approved kinase inhibitor phenocopied the effect of depletion by RNAi and reduced the growth of AR-positive, but not AR negative, treatment-resistant prostate cancer cells. Thus, our screen has yielded new AR regulators including drugable targets that reduce the proliferation of castration-resistant prostate cancer cells.
A genome-wide RNA interference screen identifies new regulators of androgen receptor function in prostate cancer cells.
Cell line
View SamplesWe introduce a family of multivalent peptidomimetic conjugates that modulate the activity of the androgen receptor (AR). Bioactive ethisterone ligands were conjugated to a set of sequence-specific peptoid oligomers. Certain multivalent peptoid conjugates enhance AR-mediated transcriptional activation. We identify a linear and a cyclic conjugate that exhibit potent anti-proliferative activity in LNCaP-abl cells, a model of therapy-resistant prostate cancer. The linear conjugate blocks AR action by competing for ligand binding. In contrast, the cyclic conjugate is active despite its inability to compete against endogenous ligand for binding to AR in vitro, suggesting a non-competitive mode of action. These results establish a versatile platform to design competitive and non-competitive AR modulators with potential therapeutic significance.
Androgen receptor antagonism by divalent ethisterone conjugates in castrate-resistant prostate cancer cells.
Cell line
View SamplesNeurosphere cultures prepared from E14.5 mouse cerebral cortex at passage 3 were treated for 4 hours with 100 nM dexamethasone
Caveolin-1 regulates genomic action of the glucocorticoid receptor in neural stem cells.
Specimen part, Treatment
View SamplesThe androgen receptor (AR) directs diverse biological processes through interaction with coregulators such as androgen receptor trapped clone-27 (ART-27). The impact of ART-27 on genome-wide transcription was examined. The studies indicate that loss of ART-27 enhances expression of many androgen-regulated genes, suggesting that ART-27 inhibits gene expression. Surprisingly, classes of genes that are upregulated upon ART-27 depletion include regulators of DNA damage checkpoint and cell cycle progression, suggesting that ART-27 functions to keep expression levels of these genes low.
Genome-wide impact of androgen receptor trapped clone-27 loss on androgen-regulated transcription in prostate cancer cells.
Sex, Specimen part
View SamplesLiver X Receptors (LXRa and ß) are ligand-activated transcription factors that play a key role in the control of lipid homeostasis, as well as modulation of immunity and inflammation. LXR activity can be regulated by posttranslational modifications, such as phosphorylation. This study aims to assess changes in the hepatic transcriptional profiles of mice that carry a whole-body phosphorylation deficient knock in mutant of LXRa (S196A) compared to wild-type (WT) upon being fed a HFHC diet. Overall design: Liver mRNA profiles of either wild-type (WT) or LXRa-S196A female mice after being fed a High Fat-High Cholesterol diet for 6 weeks. Three biological replicate samples for each group are included. WT samples are used as controls.
Impaired LXRα Phosphorylation Attenuates Progression of Fatty Liver Disease.
Sex, Specimen part, Cell line, Subject
View SamplesLiver X Receptors (LXRa and ß) are ligand-activated transcription factors that play a key role in the control of lipid homeostasis, as well as modulation of immunity and inflammation. LXR activity can be regulated by posttranslational modifications, such as phosphorylation. This study aims to assess changes in the hepatic transcriptional profiles of mice that carry a whole-body phosphorylation deficient knock in mutant of LXRa (S196A) compared to wild-type (WT) fed a chow diet. Overall design: Liver mRNA profiles of either wild-type (WT) or LXRa-S196A 16-week old female mice on a chow diet. Three biological replicate samples for each group are included. WT samples are used as controls.
Impaired LXRα Phosphorylation Attenuates Progression of Fatty Liver Disease.
Specimen part, Cell line, Subject
View SamplesThousands of long non-coding RNAs (lncRNAs) have been identified in the human genome, many of which are not conserved in lower mammals. The majority of these lncRNAs remain functionally uncharacterized and may have important implications in human physiology and disease. Here, we identify a primate-specific lncRNA, CHROME, which is increased in the plasma and atherosclerotic plaques of individuals with coronary artery disease compared to healthy controls. Using a loss-of-function approach, we show that CHROME functions as a competing endogenous RNA of microRNAs and regulates the concentration and biological functions of target genes. Overall design: We used three replicate samples of HEPG2 cells that were treated with shRNA for CHROME compated to three replicate control samples.
The long noncoding RNA CHROME regulates cholesterol homeostasis in primate.
Specimen part, Cell line, Subject
View SamplesMatriptase-2 (Tmprss6), a recently described member of the TTSP family, is an essential regulator of iron homeostasis. Tmprss6-/- mice display an overt phenotype of alopecia and a severe iron deficiency anemia. These hematological alterations found in Tmprss6-/- mice are accompanied by a marked up-regulation of hepcidin, a negative regulator of iron export into plasma.
Membrane-bound serine protease matriptase-2 (Tmprss6) is an essential regulator of iron homeostasis.
Sex, Age, Specimen part
View SamplesDietary intervention constitutes a feasible approach for modulating metabolism and improving healthspan and lifespan. Methionine restriction (MR) delays the appearance of age-related diseases and increases longevity in normal mice. However, the effect of MR on premature aging remains to be elucidated. Here, we describe that MR extends lifespan in two different mouse models of Hutchinson-Gilford progeria syndrome (HGPS) by reversing the transcriptome alterations in inflammation and DNA-damage response genes present in this condition. Further, MR improves the lipid profile and alters the levels of bile acids, both in wild-type and in progeroid mice. Notably, treatment with the bile acid cholic acid improves healthspan and lifespan in vivo. These results suggest the existence of a metabolic pathway involved in the longevity extension achieved by MR and support the possibility of dietary interventions for treating progeria.
Methionine Restriction Extends Lifespan in Progeroid Mice and Alters Lipid and Bile Acid Metabolism.
Sex, Age, Specimen part
View Samples