Overexpression of Androgen Receptor in Prostate Cancer

Kastraatioresistentti eturauhassyöpä (castration resistant prostate cancer, CRPC) on tappava tauti. CRPC:n kehittymismekanismit tunnetaan vain osittain. Parhaiten ymmärretty muutos CRPC:ssä on androgeenireseptorin (AR) yli-ilmentyminen. Eturauhassolut ovat riippuvaisia AR:sta kasvaakseen ja erilaistuakseen, samoin kuin eturauhassyöpäsolut ovat riippuvaisia AR:sta taudin etenemiseksi. Siten AR on yksi suurimmista CRPC:n kehityksen edistäjistä. Tämä tutkimus pyrki selvittämään molekyylitason muutoksia androgeenireseptoria yli-ilmentävissä soluissa erityisesti transkriptionaalisella tasolla. Lisäksi tämä tutkimus pyrki tunnistamaan niitä AR:n kohdegeenejä, jotka ovat tärkeitä eturauhassyövän etenemiselle ja joita voitaisiin käyttää biomarkkereina tai lääkkeiden kohdemolekyyleinä. Tulokset osoittivat, että AR:n yli-ilmentäminen tehostaa reseptorin sitoutumista kromatiiniin jo suhteellisen alhaisissa androgeenipitoisuuksissa. Samoissa olosuhteissa myös reseptorin ja muiden transkriptiokoneiston perusosien, kuten RNA polymeraasin, kromatiiniin sitoutumisen dynamiikka muuttui. Sitoutuminen tapahtui aiemmin ja voimakkaammin androgeenireseptoria yli-ilmentävissä soluissa. Tulosten perusteella kromatiini on avoimemmassa muodossa AR:a yli-ilmentävissä soluissa jo vähähormonisissa olosuhteissa. Siten AR yli-ilmentyminen suosii kromatiinin saavutettavuutta, mikä johtaa tehostettuun transkriptioon. AR:n sitoutuminen kromatiiniin ja transkription tehostuminen ovat erilaiset eri geeneillä. Tutkimuksessa tunnistettiin ja karakterisoitiin myös uusia AR kohdegeenejä. SKP2, ZWINT ja FEN1 yli-ilmentyivät CRPC:ssa, kun taas SNAI2:n ilmentyminen oli vähentynyt. Funktionaaliset kokeet osoittivat, että ZWINT, SNAI2 ja FEN1 voivat olla tärkeitä eturauhassyövän kasvulle. FEN1:n ilmentyminen assosioitui myös syövän uusiutumiseen. FEN1 voi siis olla merkittävä tekijä syövän etenemisessä kastraatioresistenttiin vaiheeseen ja mahdollinen lääkekohde. Kaiken kaikkiaan nämä tulokset tarjoavat mekanismin AR yli-ilmentymisen aiheuttamalle kastraatioresistenssille.Castration-resistant prostate cancer (CRPC) is a deadly disease. The mechanism by which CRPC develops is only partially understood. The best understood alteration in CRPC is the overexpression of the androgen receptor (AR). Prostate cells rely on AR for growth and differentiation as much as prostate cancer (PC) cells rely on it for disease progression. Thus, AR is one of the major contributors to the development of CRPC. This study aimed to investigate the molecular changes occurring in AR-overexpressing PC cells, particularly at the transcriptional level. Furthermore, this study also aimed to identify AR target genes that are important for PC progression that could be used as potential drug targets or biomarkers. The data demonstrated that the overexpression of AR enhances the binding of the receptor to chromatin in the presence of relatively low concentrations of androgens. Furthermore, under the same conditions, AR overexpression also altered the dynamics of chromatin binding of the receptor and the binding of basic components of the transcriptional machinery, such as RNA Pol II. The recruitment occurred earlier and more powerfully in AR-overexpressing cells. These changes seemed to translate into an increased acetylation of positioned histones. Furthermore, the data suggested that the chromatin is more open in AR-overexpressing cells that are already in hormone-deprived conditions. Thus, AR overexpression favors chromatin accessibility, which results in enhanced gene transcription. Interestingly, the AR and RNA Pol II binding pattern, and the transcriptional enhancement of the target genes differ from gene to gene. In addition, several new AR target genes were identified and characterized. SKP2, ZWINT and FEN1 were found to be overexpressed in CRPC specimens, whereas SNAI2 expression was reduced. Functional studies showed that ZWINT, SNAI2 and FEN1 may be important in PC cell growth. FEN1 overexpression was also associated with a shorter time to progression. Thus, FEN1 may be important in the progression of PC to CRPC and may represent a potential drug target. Altogether, these results offer a mechanism for how overexpression of AR leads to resistance to androgen ablation

CTCF modulates Estrogen Receptor function through specific chromatin and nuclear matrix interactions

Enhancer regions and transcription start sites of estrogen-target regulated genes are connected by means of Estrogen Receptor long-range chromatin interactions. Yet, the complete molecular mechanisms controlling the transcriptional output of engaged enhancers and subsequent activation of coding genes remain elusive. Here, we report that CTCF binding to enhancer RNAs is enriched when breast cancer cells are stimulated with estrogen. CTCF binding to enhancer regions results in modulation of estrogen-induced gene transcription by preventing Estrogen Receptor chromatin binding and by hindering the formation of additional enhancer-promoter ER looping. Furthermore, the depletion of CTCF facilitates the expression of target genes associated with cell division and increases the rate of breast cancer cell proliferation. We have also uncovered a genomic network connecting loci enriched in cell cycle regulator genes to nuclear lamina that mediates the CTCF function. The nuclear lamina and chromatin interactions are regulated by estrogen-ER. We have observed that the chromatin loops formed when cells are treated with estrogen establish contacts with the nuclear lamina. Once there, the portion of CTCF associated with the nuclear lamina interacts with enhancer regions, limiting the formation of ER loops and the induction of genes present in the loop. Collectively, our results reveal an important, unanticipated interplay between CTCF and nuclear lamina to control the transcription of ER target genes, which has great implications in the rate of growth of breast cancer cells

Leituras do feminino nas culturas lusófonas, ibéricas e eslavas

Recensão crítica ao livro Os Estudos de Género da Perspetiva Ibérica e Eslava, organizado por Beata Cieszynska e Fabio Mario da Silva.info:eu-repo/semantics/publishedVersio

Patient-derived acellular ascites fluid affects drug responses in ovarian cancer cell lines through the activation of key signalling pathways

Malignant ascites is commonly produced in advanced epithelial ovarian cancer (EOC) and serves as unique microenvironment for tumour cells. Acellular ascites fluid (AAF) is rich in signalling molecules and has been proposed to play a role in the induction of chemoresistance. Through in vitro testing of drug sensitivity and by assessing intracellular phosphorylation status in response to mono- and combination treatment of five EOC cell lines after incubation with AAFs derived from 20 different patients, we investigated the chemoresistance-inducing potential of ascites. We show that the addition of AAFs to the culture media of EOC cell lines has the potential to induce resistance to standard-of-care drugs (SCDs). We also show that AAFs induce time- and concentration-dependent activation of downstream signalling to signal transducer and activator of transcription 3 (STAT3), and concomitantly altered phosphorylation of mitogen-activated protein kinase kinase (MEK), phosphoinositide 3-kinase (PI3K)–protein kinase B (AKT) and nuclear factor NF-kappa-B (NFκB). Antibodies targeting the interleukin-6 receptor (IL6R) effectively blocked phosphorylation of STAT3 and STAT1. Treatments with SCDs were effective in reducing cell viability in only a third of 30 clinically relevant conditions examined, defined as combinations of drugs, different cell lines and AAFs. Combinations of SCDs and novel therapeutics such as trametinib, fludarabine or rapamycin were superior in another third. Notably, we could nominate effective treatment combinations in almost all conditions except in 4 out of 30 conditions, in which trametinib or fludarabine showed higher efficacy alone. Taken together, our study underscores the importance of the molecular characterisation of individual patients' AAFs and the impact on treatment resistance as providing clinically meaningful information for future precision treatment approaches in EOC.Peer reviewe

The Quandary of DNA-Based Treatment Assessment in De Novo Metastatic Prostate Cancer in the Era of Precision Oncology.

Guidelines for genetic testing have been established for multiple tumor types, frequently indicating the most confident molecularly targeted treatment options. However, considering the often-complex presentation of individual cancer patients, in addition to the combinatorial complexity and inherent uncertainties of molecular findings, deriving optimal treatment strategies frequently becomes very challenging. Here, we report a comprehensive analysis of a 68-year-old male with metastatic prostate cancer, encompassing pathology and MRI findings, transcriptomic results, and key genomics findings from whole-exome sequencing, both somatic aberrations and germline variants. We identify multiple somatic aberrations that are known to be enriched in prostate cancer, including a deletion of PTEN and a fusion transcript involving BRCA2. The gene expression patterns in the tumor biopsy were also strikingly similar to prostate tumor samples from TCGA. Furthermore, we detected multiple lines of evidence for homologous recombination repair deficiency (HRD), including a dominant contribution by mutational signature SBS3, which is specifically attributed to HRD. On the basis of the genomic and transcriptomic findings, and in light of the clinical case presentation, we discussed the personalized treatment options that exist for this patient and the various challenges that one faces in the process of translating high-throughput sequencing data towards treatment regimens

Gene regulation network analysis on human prostate orthografts highlights a potential role for the JMJD6 regulon in clinical prostate cancer

Background: Prostate cancer (PCa) is the second most common tumour diagnosed in men. Tumoral heterogeneity in PCa creates a significant challenge to develop robust prognostic markers and novel targets for therapy. An analysis of gene regulatory networks (GRNs) in PCa may provide insight into progressive PCa. Herein, we exploited a graph-based enrichment score to integrate data from GRNs identified in preclinical prostate orthografts and differentially expressed genes in clinical resected PCa. We identified active regulons (transcriptional regulators and their targeted genes) associated with PCa recurrence following radical prostatectomy. Methods: The expression of known transcription factors and co-factors was analysed in a panel of prostate orthografts (n = 18). We searched for genes (as part of individual GRNs) predicted to be regulated by the highest number of transcriptional factors. Using differentially expressed gene analysis (on a per sample basis) coupled with gene graph enrichment analysis, we identified candidate genes and associated GRNs in PCa within the UTA cohort, with the most enriched regulon being JMJD6, which was further validated in two additional cohorts, namely EMC and ICGC cohorts. Cox regression analysis was performed to evaluate the association of the JMJD6 regulon activity with disease-free survival time in the three clinical cohorts as well as compared to three published prognostic gene signatures (TMCC11, BROMO-10 and HYPOXIA-28). Results: 1308 regulons were correlated to transcriptomic data from the three clinical prostatectomy cohorts. The JMJD6 regulon was identified as the top enriched regulon in the UTA cohort and again validated in the EMC cohort as the top-ranking regulon. In both UTA and EMC cohorts, the JMJD6 regulon was significantly associated with cancer recurrence. Active JMJD6 regulon also correlated with disease recurrence in the ICGC cohort. Furthermore, Kaplan–Meier analysis confirmed shorter time to recurrence in patients with active JMJD6 regulon for all three clinical cohorts (UTA, EMC and ICGC), which was not the case for three published prognostic gene signatures (TMCC11, BROMO-10 and HYPOXIA-28). In multivariate analysis, the JMJD6 regulon status significantly predicted disease recurrence in the UTA and EMC, but not ICGC datasets, while none of the three published signatures significantly prognosticate for cancer recurrence. Conclusions: We have characterised gene regulatory networks from preclinical prostate orthografts and applied transcriptomic data from three clinical cohorts to evaluate the prognostic potential of the JMJD6 regulon

Lipid degradation promotes prostate cancer cell survival

Prostate cancer is the most common male cancer and androgen receptor (AR) is the major driver of the disease. Here we show that Enoyl-CoA delta isomerase 2 (ECI2) is a novel AR-target that promotes prostate cancer cell survival. Increased ECI2 expression predicts mortality in prostate cancer patients (p = 0.0086). ECI2 encodes for an enzyme involved in lipid metabolism, and we use multiple metabolite profiling platforms and RNA-seq to show that inhibition of ECI2 expression leads to decreased glucose utilization, accumulation of fatty acids and down-regulation of cell cycle related genes. In normal cells, decrease in fatty acid degradation is compensated by increased consumption of glucose, and here we demonstrate that prostate cancer cells are not able to respond to decreased fatty acid degradation. Instead, prostate cancer cells activate incomplete autophagy, which is followed by activation of the cell death response. Finally, we identified a clinically approved compound, perhexiline, which inhibits fatty acid degradation, and replicates the major findings for ECI2 knockdown. This work shows that prostate cancer cells require lipid degradation for survival and identifies a small molecule inhibitor with therapeutic potential.</p

Androgen regulation of the androgen receptor coregulators

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Overexpression of Androgen Receptor in Prostate Cancer

Kastraatioresistentti eturauhassyöpä (castration resistant prostate cancer, CRPC) on tappava tauti. CRPC:n kehittymismekanismit tunnetaan vain osittain. Parhaiten ymmärretty muutos CRPC:ssä on androgeenireseptorin (AR) yli-ilmentyminen. Eturauhassolut ovat riippuvaisia AR:sta kasvaakseen ja erilaistuakseen, samoin kuin eturauhassyöpäsolut ovat riippuvaisia AR:sta taudin etenemiseksi. Siten AR on yksi suurimmista CRPC:n kehityksen edistäjistä. Tämä tutkimus pyrki selvittämään molekyylitason muutoksia androgeenireseptoria yli-ilmentävissä soluissa erityisesti transkriptionaalisella tasolla. Lisäksi tämä tutkimus pyrki tunnistamaan niitä AR:n kohdegeenejä, jotka ovat tärkeitä eturauhassyövän etenemiselle ja joita voitaisiin käyttää biomarkkereina tai lääkkeiden kohdemolekyyleinä. Tulokset osoittivat, että AR:n yli-ilmentäminen tehostaa reseptorin sitoutumista kromatiiniin jo suhteellisen alhaisissa androgeenipitoisuuksissa. Samoissa olosuhteissa myös reseptorin ja muiden transkriptiokoneiston perusosien, kuten RNA polymeraasin, kromatiiniin sitoutumisen dynamiikka muuttui. Sitoutuminen tapahtui aiemmin ja voimakkaammin androgeenireseptoria yli-ilmentävissä soluissa. Tulosten perusteella kromatiini on avoimemmassa muodossa AR:a yli-ilmentävissä soluissa jo vähähormonisissa olosuhteissa. Siten AR yli-ilmentyminen suosii kromatiinin saavutettavuutta, mikä johtaa tehostettuun transkriptioon. AR:n sitoutuminen kromatiiniin ja transkription tehostuminen ovat erilaiset eri geeneillä. Tutkimuksessa tunnistettiin ja karakterisoitiin myös uusia AR kohdegeenejä. SKP2, ZWINT ja FEN1 yli-ilmentyivät CRPC:ssa, kun taas SNAI2:n ilmentyminen oli vähentynyt. Funktionaaliset kokeet osoittivat, että ZWINT, SNAI2 ja FEN1 voivat olla tärkeitä eturauhassyövän kasvulle. FEN1:n ilmentyminen assosioitui myös syövän uusiutumiseen. FEN1 voi siis olla merkittävä tekijä syövän etenemisessä kastraatioresistenttiin vaiheeseen ja mahdollinen lääkekohde. Kaiken kaikkiaan nämä tulokset tarjoavat mekanismin AR yli-ilmentymisen aiheuttamalle kastraatioresistenssille.Castration-resistant prostate cancer (CRPC) is a deadly disease. The mechanism by which CRPC develops is only partially understood. The best understood alteration in CRPC is the overexpression of the androgen receptor (AR). Prostate cells rely on AR for growth and differentiation as much as prostate cancer (PC) cells rely on it for disease progression. Thus, AR is one of the major contributors to the development of CRPC. This study aimed to investigate the molecular changes occurring in AR-overexpressing PC cells, particularly at the transcriptional level. Furthermore, this study also aimed to identify AR target genes that are important for PC progression that could be used as potential drug targets or biomarkers. The data demonstrated that the overexpression of AR enhances the binding of the receptor to chromatin in the presence of relatively low concentrations of androgens. Furthermore, under the same conditions, AR overexpression also altered the dynamics of chromatin binding of the receptor and the binding of basic components of the transcriptional machinery, such as RNA Pol II. The recruitment occurred earlier and more powerfully in AR-overexpressing cells. These changes seemed to translate into an increased acetylation of positioned histones. Furthermore, the data suggested that the chromatin is more open in AR-overexpressing cells that are already in hormone-deprived conditions. Thus, AR overexpression favors chromatin accessibility, which results in enhanced gene transcription. Interestingly, the AR and RNA Pol II binding pattern, and the transcriptional enhancement of the target genes differ from gene to gene. In addition, several new AR target genes were identified and characterized. SKP2, ZWINT and FEN1 were found to be overexpressed in CRPC specimens, whereas SNAI2 expression was reduced. Functional studies showed that ZWINT, SNAI2 and FEN1 may be important in PC cell growth. FEN1 overexpression was also associated with a shorter time to progression. Thus, FEN1 may be important in the progression of PC to CRPC and may represent a potential drug target. Altogether, these results offer a mechanism for how overexpression of AR leads to resistance to androgen ablation