The androgen receptor (AR) is an established orchestrator of cell metabolism in prostate cancer (PCa), notably by inducing an oxidative mitochondrial program. Intriguingly, AR regulates cytoplasmic ...isocitrate dehydrogenase 1 (IDH1), but not its mitochondrial counterparts IDH2 and IDH3. Here, we aimed to understand the functional role of IDH1 in PCa. Mouse models, in vitro human PCa cell lines, and human patient-derived organoids (PDOs) were used to study the expression and activity of IDH enzymes in the normal prostate and PCa. Genetic and pharmacological inhibition of IDH1 was then combined with extracellular flux analyses and gas chromatography-mass spectrometry for metabolomic analyses and cancer cell proliferation in vitro and in vivo. In PCa cells, more than 90% of the total IDH activity is mediated through IDH1 rather than its mitochondrial counterparts. This profile seems to originate from the specialized prostate metabolic program, as observed using mouse prostate and PDOs. Pharmacological and genetic inhibition of IDH1 impaired mitochondrial respiration, suggesting that this cytoplasmic enzyme contributes to the mitochondrial tricarboxylic acid cycle (TCA) in PCa. Mass spectrometry-based metabolomics confirmed this hypothesis, showing that inhibition of IDH1 impairs carbon flux into the TCA cycle. Consequently, inhibition of IDH1 decreased PCa cell proliferation in vitro and in vivo. These results demonstrate that PCa cells have a hybrid cytoplasmic-mitochondrial TCA cycle that depends on IDH1. This metabolic enzyme represents a metabolic vulnerability of PCa cells and a potential new therapeutic target.
The prostate is metabolically unique: it produces high levels of citrate for secretion via a truncated tricarboxylic acid (TCA) cycle to maintain male fertility. In prostate cancer (PCa), this ...phenotype is reprogrammed, making it an interesting therapeutic target. However, how the truncated prostate TCA cycle works is still not completely understood.
We optimized targeted metabolomics in mouse and human organoid models in ex vivo primary culture. We then used stable isotope tracer analyses to identify the pathways that fuel citrate synthesis.
First, mouse and human organoids were shown to recapitulate the unique citrate-secretory program of the prostate, thus representing a novel model that reproduces this unusual metabolic profile. Using stable isotope tracer analysis, several key nutrients were shown to allow the completion of the prostate TCA cycle, revealing a much more complex metabolic profile than originally anticipated. Indeed, along with the known pathway of aspartate replenishing oxaloacetate, glutamine was shown to fuel citrate synthesis through both glutaminolysis and reductive carboxylation in a GLS1-dependent manner. In human organoids, aspartate entered the TCA cycle at the malate entry point, upstream of oxaloacetate. Our results demonstrate that the citrate-secretory phenotype of prostate organoids is supported by the known aspartate–oxaloacetate–citrate pathway, but also by at least three additional pathways: glutaminolysis, reductive carboxylation, and aspartate–malate conversion.
Our results add a significant new dimension to the prostate citrate-secretory phenotype, with at least four distinct pathways being involved in citrate synthesis. Better understanding this distinctive citrate metabolic program will have applications in both male fertility as well as in the development of novel targeted anti-metabolic therapies for PCa.
•Targeted metabolomics and stable isotope tracer analysis were optimized in mouse and human prostate organoids.•Organoids recapitulate the unique citrate-secretory phenotype of the prostate.•Glutamine fuels citrate synthesis for secretion by glutaminolysis and reductive carboxylation.•Aspartate enters the TCA cycle at different entry points in mouse and human prostate organoids for citrate production.•We revealed a much more complex TCA cycle in the prostate than originally anticipated.
Cellular homeostasis requires the orderly expression of thousands of transcripts. Gene expression is regulated by numerous proteins that recognize post-translational modifications-in particular, the ...acetylation of lysine residues (Kac) on histones. In addition to affecting the general condensation state of the chromatin, acetylated histones act as anchor points for bromodomain (BRD)-containing adapter proteins. BRDs are the primary Kac reader domains in humans, and proteins containing them act as chromatin scaffolds that organize large networks of interactions to regulate transcription. To characterize BRD-dependent interaction networks, we established cell lines in which histone acetylation is dependent on acetate supplementation. To do this, we used genome editing to knock out ATP citrate lyase (ACLY), the enzyme responsible for converting citrate to oxaloacetate and acetyl-CoA in the cytoplasm and nucleus. In our cellular model, removing acetate from the culture medium resulted in the rapid catabolism of acetylated histones to restore the nucleocytoplasmic acetyl-CoA pool. Here we report the use of our new model in functional proteomics studies to characterize BRD-dependent interaction networks on the chromatin.
•Functional genomic approaches have shed light on a new function of AR.•AR is a master regulator of cellular energy metabolism.•AR induces several specific metabolic pathways in prostate cancer.•AR ...controls several regulatory factors to establish a specific metabolic program.
Sex-steroid hormones have been investigated for decades for their oncogenic properties in hormone-dependent cancers. The increasing body of knowledge on the biological actions of androgens in prostate cancer has led to the development of several targeted therapies that still represent the standard of care for cancer patients to this day. In the prostate, androgens promote cellular differentiation and proper tissue development. These hormones also promote the aberrant proliferation and survival of prostate cancer cells. Over the past few years, sequencing technologies for functional genomic analyses have rapidly expanded, revealing novel functions of sex-steroid hormone receptors other than their classic roles. In this article, we will focus on transcriptomic- and genomic-based evidence that demonstrates the importance of the androgen receptor signaling in the regulation of prostate cancer cell metabolism. This is significant because the reprogramming of cell metabolism is a hallmark of cancer. In fact, it is clear now that the androgen receptor contributes to the reprogramming of specific cellular metabolic pathways that promote tumor growth and disease progression, including aerobic glycolysis, mitochondrial respiration, fatty acid ß-oxidation, and de novo lipid synthesis. Overall, beyond regulating development, differentiation, and proliferation, the androgen receptor is also a master regulator of cellular energy metabolism.
Abstract
Prostate cancer cells (PCa) are dependent on the androgen receptor (AR) for their aberrant proliferation and survival. We have recently discovered that AR induces a reprogramming of PCa cell ...metabolism by controlling the cytoplasmic wild-type enzyme isocitrate dehydrogenase 1 (IDH1), which results in an enhanced proliferation of tumour cells. However, the specific metabolic functions of IDH1 in PCa or how to use the reliance of tumour cells on this enzyme as a therapeutic avenue, is elusive. In in vitro human PCa models, we showed that IDH1 protein levels and activity are increased in an AR-dependent manner. Using pharmacological and genetic tools, we showed that IDH1 is a major contributor to the replenishment of NADPH levels in PCa. This cofactor plays a key role in the synthesis of biomaterials required for cellular division, and our results indicate that IDH1 contribute to 30-40% of total cellular NADPH levels. In that context, blockade of IDH1 was shown to alter the mTOR signaling, a central regulator of cellular anabolism, which is linked to decreased cellular proliferation rates. FDA-approved pharmacological inhibitors of mutant IDH1 significantly inhibited IDH activity and proliferation in PCa cells, suggesting that such inhibitors could be used to treat PCa patients even in absence of IDH1 mutation. Globally, our results demonstrate that IDH1 is a key player in proliferative anabolic pathways in PCa. Importantly, they also support the hypothesis that inhibition of IDH1 using already-approved molecules represents one viable therapeutic solution.
Citation Format: Kevin Gonthier, Cindy Weidmann, Lilianne Frégeau-Proulx, Étienne Audet-Walsh. Targeting the isocitrate dehydrogenase 1 (IDH1) metabolic enzyme in prostate cancer abstract. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3731.
Mutations of the isocitrate dehydrogenase genes
and
, key enzymes involved in citrate metabolism, are important oncogenic events in several cancer types, including in 1%-3% of all prostate cancer ...cases. However, if
and other IDH isoforms are associated with prostate cancer progression, as well as the regulatory factors controlling their expression and activity, remain mostly unknown. Using publicly available datasets, we showed that prostate cancer harbors the highest
expression across the human cancer spectrum and that
expression is altered during prostate cancer progression. We showed that the androgen receptor (AR), a key oncogene in prostate cancer, controls multiple IDH isoforms in both
and
models, predominantly positively regulating
. Chromatin immunoprecipitation experiments confirmed the recruitment of AR at several regulatory regions of
and enzymatic assays demonstrated that AR significantly induces IDH activity. Genetic blockade of
significantly impaired prostate cancer cell proliferation, consistent with IDH1 having a key function in these cancer cells. Importantly, knockdown of
blocked the AR-mediated induction in IDH activity, indicating that AR promotes a mitochondrial to cytoplasmic reprogramming of IDH activity. Overall, our study demonstrates that
expression is associated with prostate cancer progression, that AR signaling integrates one of the first transcriptional mechanisms shown to regulate
, and that AR reprograms prostate cancer cell metabolism by selectively inducing extra-mitochondrial IDH activity. IMPLICATIONS: The discovery that AR reprograms IDH activity highlights a novel metabolic reprogramming necessary for prostate cancer growth and suggests targeting IDH activity as a new therapeutic approach for prostate cancer treatment.
Abstract
A primary function of the prostate is to synthesize and secrete high levels of citrate by way of a unique metabolic profile regulated by the androgen receptor (AR). Prostate cancer (PCa) is ...an androgen-dependent disease that is characterized by early reprogramming of citrate metabolism. Accordingly, mutations of the isocitrate dehydrogenase genes IDH1 and IDH2, which are key enzymes involved in the regulation of cellular citrate levels, have been demonstrated as important oncogenic events in several cancer types, including in about 3% of all PCa cases. However, if IDH1 and other IDH isoforms are associated with PCa progression as well as the regulatory factors controlling their expression remain mostly unknown. Across the human cancer spectrum, PCa appears to be the cancer type with the highest expression of IDH1, with levels even higher than common cancers associated with IDH1 mutations such as gliomas. Using publicly available datasets and quantitative PCR, we showed that IDH1 is the predominant IDH isoform expressed in PCa cells. In PCa, the androgen receptor was found to regulate several IDH isoforms in both in vitro and in vivo models of PCa, predominantly positively regulating IDH1. Chromatin immunoprecipitation experiments confirmed the recruitment of AR at several regulatory regions of IDH1 and IDH2. IDH1 and other IDH isoforms were shown to be significantly altered during PCa progression, which is consistent with a reprogramming of citrate metabolism in PCa. In addition, modulation of IDH expression significantly altered PCa cell proliferation and metabolism. Overall, our study indicates that IDH gene regulation is associated with PCa progression and that AR plays a significant role in the regulation of IDH genes.
Citation Format: Kevin Gonthier, Raghavendra TK Poluri, Cindy Weidmann, Etienne Audet-Walsh. Association of IDH genes with prostate cancer progression and their regulation by the androgen receptor abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1853.
Just like the androgen receptor (AR), the estrogen receptor α (ERα) is expressed in the prostate and is thought to influence prostate cancer (PCa) biology. Yet the incomplete understanding of ERα ...functions in PCa hinders our ability to fully comprehend its clinical relevance and restricts the repurposing of estrogen-targeted therapies for the treatment of this disease. Using 2 human PCa tissue microarray cohorts, we first demonstrate that nuclear ERα expression was heterogeneous among patients, being detected in only half of the tumors. Positive nuclear ERα levels were correlated with disease recurrence, progression to metastatic PCa, and patient survival. Using in vitro and in vivo models of the normal prostate and PCa, bulk and single-cell RNA-Seq analyses revealed that estrogens partially mimicked the androgen transcriptional response and activated specific biological pathways linked to proliferation and metabolism. Bioenergetic flux assays and metabolomics confirmed the regulation of cancer metabolism by estrogens, supporting proliferation. Using cancer cell lines and patient-derived organoids, selective estrogen receptor modulators, a pure anti-estrogen, and genetic approaches impaired cancer cell proliferation and growth in an ERα-dependent manner. Overall, our study revealed that, when expressed, ERα functionally reprogrammed PCa metabolism, was associated with disease progression, and could be targeted for therapeutic purposes.
Abstract Just as the androgen receptor (AR), the estrogen receptor α (ERα) is expressed in the prostate and is thought to influence prostate cancer (PCa) biology. Yet, the incomplete understanding of ...ERα cellular functions in PCa hinders our ability to fully comprehend its clinical relevance and restricts the repurposing of estrogen-targeted therapies for treatment of this disease. Using two human PCa tissue microarray cohorts, we first demonstrated that nuclear ERα expression was heterogeneous between patients, being only detected in half of tumors. Positive nuclear ERα levels were correlated with disease recurrence, progression to metastatic PCa, and patient survival. Using in vitro and in vivo models of the normal prostate and PCa, bulk and single cell RNA-seq analyses revealed that estrogens partially mimic the androgen transcriptional response and induce specific biological pathways linked to cellular proliferation and metabolism. Bioenergetic flux assays and metabolomics confirmed regulation of cancer metabolism by estrogens, supporting proliferation. Using cancer cell lines and patient-derived organoids, selective estrogen receptor modulators, a pure anti-estrogen, and genetic approaches impaired cancer cell proliferation and growth in an ERα-dependent manner. Overall, our study revealed that, when expressed, ERα functionally reprograms PCa metabolism, is associated with disease progression, and could be targeted for therapeutic purposes. Citation Format: Camille Lafront, Lucas Germain, Gabriel H. Campolina-Silva, Cindy Weidmann, Line Berthiaume, Hélène Hovington, Hervé Brisson, Cynthia Jobin, Lilianne Frégeau-Proulx, Raul Cotau, Kevin Gonthier, Aurélie Lacouture, Patrick Caron, Claire Ménard, Chantal Atallah, Julie Riopel, Éva Latulippe, Alain Bergeron, Paul Toren, Chantal Guillemette, Martin Pelletier, Yves Fradet, Clémence Belleannée, Frédéric Pouliot, Louis Lacombe, Éric Lévesque, Étienne Audet-Walsh. The estrogen signaling pathway reprograms prostate cancer cell metabolism and supports proliferation and disease progression abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3046.
Abstract
Background: The androgen receptor (AR) is an established orchestrator of cell metabolism in prostate cancer (PCa), notably by inducing an oxidative mitochondrial program. Intriguingly, AR ...regulates cytoplasmic isocitrate dehydrogenase 1 (IDH1) but not its mitochondrial counterparts IDH2 and IDH3. Here, we aimed to understand the functional role of IDH1 in PCa.
Methods: Mouse models, in vitro human PCa cell lines, and human prostate organoids were used to study the expression and activity of IDH enzymes in the normal prostate and PCa. Genetic and pharmacological inhibition of IDH1 was then combined with extracellular flux analysis and gas chromatography-mass spectrometry for metabolomic analyses and cancer cell proliferation in vitro and in vivo.
Results: In PCa cells, more than 90% of the total IDH activity is mediated through IDH1 rather than its mitochondrial counterparts. This profile seems to originate from the specialized prostate metabolic program, as observed using mouse prostate and human patient-derived organoids. Pharmacological and genetic inhibition of IDH1 impaired mitochondrial respiration, suggesting that this cytoplasmic enzyme contributes to the mitochondrial tricarboxylic acid cycle (TCA) in PCa. Mass spectrometry-based metabolomics confirmed this hypothesis, showing that inhibition of IDH1 impairs carbon flux into the TCA cycle. Consequently, inhibition of IDH1 decreased PCa cell proliferation in vitro and in vivo.
Conclusions: These results demonstrate that PCa cells have a hybrid cytoplasmic-mitochondrial TCA cycle that depends on IDH1. This metabolic enzyme represents a metabolic vulnerability of PCa cells and a potential new therapeutic target.
Citation Format: Kevin Gonthier, Cindy Weidmann, Line Berthiaume, Cynthia Jobin, Aurélie Lacouture, Camille Lafront, Mario Harvey, Bertrand Neveu, Jérémy Loehr, Alain Bergeron, Yves Fradet, Louis Lacombe, Julie Riopel, Éva Latulippe, Chantal Atallah, Michael Shum, Jean-Philippe Lambert, Frédéric Pouliot, Martin Pelletier, Étienne Audet-Walsh. Isocitrate dehydrogenase 1 sustains a hybrid cytoplasmic-mitochondrial tricarboxylic acid cycle in prostate cancer. abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3700.
