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MOTIVATION: Long non-coding RNAs (lncRNAs) have gained increasing relevance in epigenetic regulation and nuclear functional organization. High-throughput sequencing approaches have revealed frequent non-coding transcription in promoter-proximal regions. However, a comprehensive catalogue of promoter-associated RNAs (paRNAs) and an analysis of the possible interactions with neighboring genes and genomic regulatory elements are missing. RESULTS: Integrating data from multiple cell types and experimental platforms we identified thousands of paRNAs in the human genome. paRNAs are transcribed in both sense and antisense orientation, are mostly non-polyadenylated and retained in the cell nucleus. Transcriptional regulators, epigenetic effectors and activating chromatin marks are enriched in paRNA-positive promoters. Furthermore, paRNA-positive promoters exhibit chromatin signatures of both active promoters and enhancers. Promoters with paRNAs reside preferentially at chromatin loop boundaries, suggesting an involvement in anchor site recognition and chromatin looping. Importantly, these features are independent of the transcriptional state of neighboring genes. Thus, paRNAs may act as cis-regulatory modules with an impact on local recruitment of transcription factors, epigenetic state and chromatin loop organization. This study provides a comprehensive analysis of the promoter-proximal transcriptome and offers novel insights into the roles of paRNAs in epigenetic processes and human diseases. AVAILABILITY AND IMPLEMENTATION: Genomic coordinates of predicted paRNAs are available at https://figshare.com: https://doi.org/10.6084/m9.figshare.7392791.v1 and https://doi.org/10.6084/m9.figshare.4856630.v2. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
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RNA Longo não Codificante/genética , Transcriptoma , Cromatina , Epigênese Genética , Humanos , Regiões Promotoras GenéticasRESUMO
In addition to its canonical role in nuclear transcription, signal transducer and activator of transcription 3 (STAT3) is emerging as an important regulator of mitochondrial function. Here, we demonstrate that a novel inhibitor that binds with high affinity to the STAT3 SH2 domain triggers a complex cascade of events initiated by interference with mitochondrial STAT3 (mSTAT3). The mSTAT3-drug interaction leads to mitochondrial dysfunction, accumulation of proteotoxic STAT3 aggregates, and cell death. The cytotoxic effects depend directly on the drug's ability to interfere with mSTAT3 and mitochondrial function, as demonstrated by site-directed mutagenesis and use of STAT3 knockout and mitochondria-depleted cells. Importantly, the lethal consequences of mSTAT3 inhibition are enhanced by glucose starvation and by increased reliance of cancer cells and tumor-initiating cells on mitochondria, resulting in potent activity in cell cultures and tumor xenografts in mice. These findings can be exploited for eliciting synthetic lethality in metabolically stressed cancer cells using high-affinity STAT3 inhibitors. Thus, this study provides insights on the role of mSTAT3 in cancer cells and a conceptual framework for developing more effective cancer therapies.
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Mitocôndrias/genética , Neoplasias/genética , Fator de Transcrição STAT3/genética , Mutações Sintéticas Letais/genética , Domínios de Homologia de src/genética , Animais , Morte Celular/genética , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos , Camundongos NusRESUMO
Castration-resistant prostate cancer (CRPC) is a frequently occurring disease with adverse clinical outcomes and limited therapeutic options. Here, we identify methionine adenosyltransferase 2a (MAT2A) as a critical driver of the androgen-indifferent state in ERG fusion-positive CRPC. MAT2A is upregulated in CRPC and cooperates with ERG in promoting cell plasticity, stemness and tumorigenesis. RNA, ATAC and ChIP-sequencing coupled with histone post-translational modification analysis by mass spectrometry show that MAT2A broadly impacts the transcriptional and epigenetic landscape. MAT2A enhances H3K4me2 at multiple genomic sites, promoting the expression of pro-tumorigenic non-canonical AR target genes. Genetic and pharmacological inhibition of MAT2A reverses the transcriptional and epigenetic remodeling in CRPC models and improves the response to AR and EZH2 inhibitors. These data reveal a role of MAT2A in epigenetic reprogramming and provide a proof of concept for testing MAT2A inhibitors in CRPC patients to improve clinical responses and prevent treatment resistance.
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Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Metionina Adenosiltransferase , Neoplasias de Próstata Resistentes à Castração , Regulador Transcricional ERG , Masculino , Humanos , Regulador Transcricional ERG/genética , Regulador Transcricional ERG/metabolismo , Metionina Adenosiltransferase/genética , Metionina Adenosiltransferase/metabolismo , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Animais , Androgênios/metabolismo , Epigenoma , Camundongos , Histonas/metabolismo , Receptores Androgênicos/metabolismo , Receptores Androgênicos/genética , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidoresRESUMO
Small interfering RNAs (siRNAs) directed to gene promoters can silence genes at the transcriptional level. siRNA-directed transcriptional silencing (RdTS) was first described in plants and yeasts and more recently in mammalian cells. RdTS has been associated with the induction of epigenetic changes and the formation of complexes containing RNA interference and chromatin-remodelling factors. Here, we show that a promoter-targeted siRNA inhibits transcription of the c-myc gene. Transcriptional silencing of c-myc did not involve changes of known epigenetic marks. Instead, the c-myc promoter-targeted siRNA interfered with transcription initiation blocking the assembly of the pre-initiation complex. Transcriptional interference depended on Argonaute 2 and a noncoding promoter-associated RNA initiated upstream and overlapping the transcription start site. Silencing of c-myc led to growth arrest, reduced clonogenic potential and senescence of c-myc over-expressing prostate cancer cells with minimal effect on normal cells. RNA-directed transcriptional interference may be a natural mechanism of transcriptional control and siRNAs targeting noncoding RNAs participating in this regulatory pathway could be valuable tools to control expression of deregulated genes in human diseases.
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Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas c-myc/genética , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Transcrição Gênica , Proteínas Argonautas , Linhagem Celular Tumoral , Proliferação de Células , Senescência Celular , Fator de Iniciação 2 em Eucariotos/metabolismo , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Neoplásico/metabolismo , RNA não Traduzido/genética , Ensaio Tumoral de Célula-TroncoRESUMO
BACKGROUND: Oncogenic transformation alters intracellular metabolism and contributes to the growth of malignant cells. Metabolomics, or the study of small molecules, can reveal insight about cancer progression that other biomarker studies cannot. Number of metabolites involved in this process have been in spotlight for cancer detection, monitoring, and therapy. RECENT FINDINGS: In this review, the "Metabolomics" is defined in terms of current technology having both clinical and translational applications. Researchers have shown metabolomics can be used to discern metabolic indicators non-invasively using different analytical methods like positron emission tomography, magnetic resonance spectroscopic imaging etc. Metabolomic profiling is a powerful and technically feasible way to track changes in tumor metabolism and gauge treatment response across time. Recent studies have shown metabolomics can also predict individual metabolic changes in response to cancer treatment, measure medication efficacy, and monitor drug resistance. Its significance in cancer development and treatment is summarized in this review. CONCLUSION: Although in infancy, metabolomics can be used to identify treatment options and/or predict responsiveness to cancer treatments. Technical challenges like database management, cost and methodical knowhow still persist. Overcoming these challenges in near further can help in designing new treatment régimes with increased sensitivity and specificity.
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Metabolômica , Neoplasias , Humanos , Metabolômica/métodos , Neoplasias/diagnóstico , Neoplasias/terapia , Neoplasias/metabolismo , Biomarcadores , Oncologia , Imageamento por Ressonância MagnéticaRESUMO
Prostate cancer (PCa) is the most common malignancy and the second leading cause of cancer-related death amongst men in the United States. Neuroendocrine prostate cancer (NEPC) can either arise de novo or emerge as a consequence of therapy. De novo NEPC is rare, with an incidence of <2% of all PCa cases. In contrast, treatment-induced NEPC is frequent with >20% of patients with metastatic castration-resistant prostate cancer (CRPC) reported to progress to neuroendocrine (NE) differentiation. The emergence of treatment-induced NEPC is linked to the increased therapeutic pressure, due to the broad application of androgen deprivation therapy (ADT) for PCa management and the development of novel more potent androgen receptor (AR) pathway inhibitors. NEPC is a high-grade tumor type characterized by aggressive phenotype and clinical behavior. Patients affected by NEPC frequently develop visceral metastases and have a poor prognosis. The molecular mechanisms underlying the development and progression of NEPC are still poorly understood. Transcriptional and epigenetic reprogramming appears to be involved in NE progression. In this review, we aim to provide a comprehensive view of the available models for NEPC detailing their strengths and limitations. Moreover, we describe novel approaches to expand the repertoire of preclinical models to better study, prevent, or reverse NEPC. The integration of multiple preclinical models along with molecular and omics approaches will provide important insights to understand disease progression and to devise novel therapeutic strategies for the management of NEPC in the near future. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Generation of organoids starting from the prostate gland of a GEMM or a human PDX Basic Protocol 2: Ex vivo tumor sphere formation.
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Neoplasias da Próstata , Masculino , Humanos , Neoplasias da Próstata/genética , Neoplasias da Próstata/terapia , Neoplasias da Próstata/metabolismo , Antagonistas de Androgênios/uso terapêutico , Próstata/metabolismo , Próstata/patologia , Antagonistas de Receptores de Andrógenos/uso terapêuticoRESUMO
Prostate cancer (PCa) is the most common cause of cancer death among African men. The analysis of microRNAs (miRNAs) in plasma extracellular vesicles (EVs) can be utilized as a non-invasive tool for the diagnosis of PCa. In this study, we used small RNA sequencing to profile miRNAs cargo in plasma EVs from South African PCa patients. We evaluated the differential expression of miRNAs between low and high Gleason scores in the plasma EVs of South African patients and in the prostatic tissue from data available in the Cancer Genome Atlas (TCGA) Data Portal. We identified 7 miRNAs differently expressed in both EVs and prostatic tissues. We evaluated their expression using qPCR in a larger cohort of 10 patients with benign prostatic hyperplasia (BPH) and 24 patients with PCa. Here, we reported that the ratio between two of these miRNAs (i.e., miR-194-5p/miR-16-5p) showed a higher concentration in PCa compared to BPH and in metastatic PCa compared to localized PCa. We explored for the first time the profiling of miRNAs cargo in plasma EVs as a tool for the identification of putative markers in the South African population. Our finding indicated the ratio miR-194-5p/miR-16-5p as a non-invasive marker for the evaluation of PCa aggressiveness in this population.
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Prostate cancer (PCa) is the most common cause of cancer death among African men. The presence of tumor-specific variations in cell-free DNA (cfDNA), such as mutations, microsatellite instability, and DNA methylation, has been explored as a source of biomarkers for cancer diagnosis. In this study, we investigated the diagnostic role of cfDNA among South African PCa patients. We performed whole exome sequencing (WES) of urinary cfDNA. We identified a novel panel of 31 significantly deregulated somatic mutated genes between PCa and benign prostatic hyperplasia (BPH). Additionally, we performed whole-genome sequencing (WGS) on matching PCa and normal prostate tissue in an independent PCa cohort from South Africa. Our results suggest that the mutations are of germline origin as they were also found in the normal prostate tissue. In conclusion, our study contributes to the knowledge of cfDNA as a biomarker for diagnosing PCa in the South African population.
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Ácidos Nucleicos Livres , Hiperplasia Prostática , Neoplasias da Próstata , Masculino , Humanos , Ácidos Nucleicos Livres/genética , África do Sul , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/genética , Hiperplasia Prostática/diagnóstico , Hiperplasia Prostática/genética , Mutação , BiomarcadoresRESUMO
BACKGROUND: Men with African ancestry are more likely to develop aggressive prostate cancer (PCa) and to die from this disease. The study of PCa in the South African population represents an opportunity for biomedical research due to the high prevalence of aggressive PCa. While inflammation is known to play a significant role in PCa progression, its association with tumor stage in populations of African descent has not been explored in detail. Identification of new metabolic biomarkers of inflammation may improve diagnosis of patients with aggressive PCa. METHODS: Plasma samples were profiled from 41 South African men with PCa using nuclear magnetic resonance (NMR) spectroscopy. A total of 41 features, including metabolites, lipid classes, total protein, and the inflammatory NMR markers, GlycA, and GlycB, were quantified from each NMR spectrum. The Bruker's B.I.-LISA protocols were used to characterize 114 parameters related to the lipoproteins. The unsupervised KODAMA method was used to stratify the patients of our cohort based on their metabolic profile. RESULTS: We found that the plasma of patients with very high risk, aggressive PCa and high level of C-reactive protein have a peculiar metabolic phenotype (metabotype) characterized by extremely high levels of GlycA and GlycB. The inflammatory processes linked to the higher level of GlycA and GlycB are characterized by a deep change of the plasma metabolome that may be used to improve the stratification of patients with PCa. We also identified a not previously known relationship between high values of VLDL and low level of GlycB in a different metabotype of patients characterized by lower-risk PCa. CONCLUSIONS: For the first time, a portrait of the metabolic changes in African men with PCa has been delineated indicating a strong association between inflammation and metabolic profiles. Our findings indicate how the metabolic profile could be used to identify those patients with high level of inflammation, characterized by aggressive PCa and short life expectancy. Integrating a metabolomic analysis as a tool for patient stratification could be important for opening the door to the development of new therapies. Further investigations are needed to understand the prevalence of an inflammatory metabotype in patients with aggressive PCa.
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The multi-kinase inhibitor sorafenib is a primary treatment modality for advanced-stage hepatocellular carcinoma (HCC). However, the therapeutic benefits are short-lived due to innate and acquired resistance. Here, we examined how HCC cells respond to sorafenib and adapt to continuous and prolonged exposure to the drug. Sorafenib-adapted HCC cells show a profound reprogramming of mitochondria function and marked activation of genes required for mitochondrial protein translation and biogenesis. Mitochondrial ribosomal proteins and components of translation and import machinery are increased in sorafenib-resistant cells and sorafenib-refractory HCC patients show similar alterations. Sorafenib-adapted cells also exhibited increased serine 727 phosphorylated (pSer727) STAT3, the prevalent form in mitochondria, suggesting that STAT3 might be an actionable target to counteract resistance. Consistently, a small-molecule STAT3 inhibitor reduces pSer727, reverts mitochondrial alterations, and enhances the response to sorafenib in resistant cells. These results sustain the importance of mitochondria plasticity in response to sorafenib and identify a clinically actionable strategy for improving the treatment efficacy in HCC patients.
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BACKGROUND: Chemotherapy is the treatment of choice for metastatic castration-resistant prostate cancer (mCRPC) nonresponsive to androgen receptor-targeted therapies. Nevertheless, the impact of chemotherapy on patient survival is limited and clinical outcome remain dismal. Bromodomain and extraterminal inhibitors (BETis) are attractive therapeutic agents and currently in clinical trials to be tested for their efficacy in prostate cancer patients. OBJECTIVE: In this study, we evaluated the activity of two clinical stage BETis, INCB054329 and INCB057643, alone and in combination with chemotherapeutics used for the treatment of mCRPC. DESIGN, SETTING, AND PARTICIPANTS: Drug activity was evaluated in vitro by MTT, clonogenic, prostato-sphere, and flow cytometry assays. The activity in vivo was evaluated in mice bearing prostate tumor (22Rv1) xenografts. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Cell growth data were analyzed to determine the maximum effect and the concentration that reduces by 50%. For concomitant treatments, the combination index was determined according to the Chou-Talalay method. For in vivo activity, changes in tumor size (T/Ci%), weight (T/Cd%), doubling time, and mouse body weight were monitored. Statistical significance was determined by one-way analysis of variance followed by a Student-Newman-Keuls or Turkey a posteriori test. RESULTS AND LIMITATIONS: INCB054329 and INCB057643 had significant activity as single agents in human prostate cancer cell lines and 22Rv1 tumor xenografts. Combined treatment with INCB057643 and any of docetaxel, olaparib, or carboplatin was synergistic/additive in vitro. Notably, INCB057643, given with a low-intensity dosing schedule, greatly enhanced the anti-tumor activity of docetaxel, carboplatin, and olaparib in 22Rv1 tumor xenografts. CONCLUSIONS: Collectively, these results provide the first evidence of the therapeutic benefit obtainable by combining BETis with non-androgen receptor-targeted therapies for the treatment of mCRPC. PATIENT SUMMARY: Chemotherapy has limited efficacy in patients with metastatic castration-resistant prostate cancer. This study provides evidence of enhanced efficacy of clinically used chemotherapeutics when given in combination with the bromodomain and extraterminal inhibitor INCB057643, expanding the horizon of the current options for the treatment of prostate cancer.
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Neoplasias de Próstata Resistentes à Castração , Animais , Ácidos Borônicos , Docetaxel , Humanos , Masculino , Camundongos , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , PirimidinasRESUMO
The TMPRSS2-ERG gene fusion is the most frequent alteration observed in human prostate cancer. However, its role in disease progression is still unclear. In this study, we uncover an important mechanism promoting ERG oncogenic activity. We show that ERG is methylated by Enhancer of zest homolog 2 (EZH2) at a specific lysine residue (K362) located within the internal auto-inhibitory domain. Mechanistically, K362 methylation modifies intra-domain interactions, favors DNA binding and enhances ERG transcriptional activity. In a genetically engineered mouse model of ERG fusion-positive prostate cancer (Pb-Cre4 Pten flox/flox Rosa26-ERG, ERG/PTEN), ERG K362 methylation is associated with PTEN loss and progression to invasive adenocarcinomas. In both ERG positive VCaP cells and ERG/PTEN mice, PTEN loss results in AKT activation and EZH2 phosphorylation at serine 21 that favors ERG methylation. We find that ERG and EZH2 interact and co-occupy several sites in the genome forming trans-activating complexes. Consistently, ERG/EZH2 co-regulated target genes are deregulated preferentially in tumors with concomitant ERG gain and PTEN loss and in castration-resistant prostate cancers. Collectively, these findings identify ERG methylation as a post-translational modification sustaining disease progression in ERG-positive prostate cancers.
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Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Lisina/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Proteínas Oncogênicas/metabolismo , Neoplasias da Próstata/metabolismo , Serina Endopeptidases/metabolismo , Regulador Transcricional ERG/metabolismo , Adenocarcinoma/genética , Animais , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Masculino , Camundongos , Camundongos Knockout , Proteínas Oncogênicas/genética , Proteínas de Fusão Oncogênica/genética , Neoplasias da Próstata/genética , Conformação Proteica , Processamento de Proteína Pós-Traducional , Alinhamento de Sequência , Serina Endopeptidases/genética , Transativadores/metabolismo , Fatores de Transcrição/genética , Regulador Transcricional ERG/genéticaRESUMO
Extracellular vesicles (EVs) are relevant means for transferring signals across cells and facilitate propagation of oncogenic stimuli promoting disease evolution and metastatic spread in cancer patients. Here, we investigated the release of miR-424 in circulating small EVs or exosomes from prostate cancer patients and assessed the functional implications in multiple experimental models. We found higher frequency of circulating miR-424 positive EVs in patients with metastatic prostate cancer compared to patients with primary tumors and BPH. Release of miR-424 in small EVs was enhanced in cell lines (LNCaPabl), transgenic mice (Pb-Cre4;Ptenflox/flox;Rosa26ERG/ERG) and patient-derived xenograft (PDX) models of aggressive disease. EVs containing miR-424 promoted stem-like traits and tumor-initiating properties in normal prostate epithelial cells while enhanced tumorigenesis in transformed prostate epithelial cells. Intravenous administration of miR-424 positive EVs to mice, mimicking blood circulation, promoted miR-424 transfer and tumor growth in xenograft models. Circulating miR-424 positive EVs from patients with aggressive primary and metastatic tumors induced stem-like features when supplemented to prostate epithelial cells. This study establishes that EVs-mediated transfer of miR-424 across heterogeneous cell populations is an important mechanism of tumor self-sustenance, disease recurrence and progression. These findings might indicate novel approaches for the management and therapy of prostate cancer.
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Transformação Celular Neoplásica/genética , Micropartículas Derivadas de Células/metabolismo , Vesículas Extracelulares/metabolismo , MicroRNAs/metabolismo , Neoplasias da Próstata , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/metabolismo , Micropartículas Derivadas de Células/genética , Vesículas Extracelulares/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Camundongos Transgênicos , MicroRNAs/genética , Modelos Teóricos , Invasividade Neoplásica , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologiaRESUMO
Driver genes with a mutually exclusive mutation pattern across tumor genomes are thought to have overlapping roles in tumorigenesis. In contrast, we show here that mutually exclusive prostate cancer driver alterations involving the ERG transcription factor and the ubiquitin ligase adaptor SPOP are synthetic sick. At the molecular level, the incompatible cancer pathways are driven by opposing functions in SPOP. ERG upregulates wild type SPOP to dampen androgen receptor (AR) signaling and sustain ERG activity through degradation of the bromodomain histone reader ZMYND11. Conversely, SPOP-mutant tumors stabilize ZMYND11 to repress ERG-function and enable oncogenic androgen receptor signaling. This dichotomy regulates the response to therapeutic interventions in the AR pathway. While mutant SPOP renders tumor cells susceptible to androgen deprivation therapies, ERG promotes sensitivity to high-dose androgen therapy and pharmacological inhibition of wild type SPOP. More generally, these results define a distinct class of antagonistic cancer drivers and a blueprint toward their therapeutic exploitation.
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Proteínas Nucleares/metabolismo , Proteínas Oncogênicas/metabolismo , Neoplasias da Próstata/metabolismo , Proteínas Repressoras/metabolismo , Regulador Transcricional ERG/metabolismo , Complexos Ubiquitina-Proteína Ligase/metabolismo , Animais , Biomarcadores Tumorais/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Proteínas Correpressoras/genética , Proteínas Correpressoras/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Células HEK293 , Humanos , Imuno-Histoquímica , Imunoprecipitação , Masculino , Camundongos , Camundongos Nus , Mutação/genética , Proteínas Nucleares/genética , Proteínas Oncogênicas/genética , Neoplasias da Próstata/genética , Ligação Proteica , Proteômica , Receptores Androgênicos/metabolismo , Proteínas Repressoras/genética , Transdução de Sinais/fisiologia , Regulador Transcricional ERG/genética , Complexos Ubiquitina-Proteína Ligase/genéticaRESUMO
OBJECTIVE: Increased activity of Sp family of transcription factors is a frequent and critical event in cancer development and progression. Genes governing tumor growth, invasion and angiogenesis are regulated by Sp factors, like Sp1, Sp3 or Sp4, and are frequently over-expressed in tumors. Targeting Sp factors has been explored as a therapeutic approach. Mithramycin (MTM) is a natural antibiotic that binds DNA and inhibit Sp1-dependent transcription. New analogues, named MTM-SDK and MTM-SK, were recently obtained by genetic engineering of the MTM biosynthetic pathway and have demonstrated improved transcriptional and antiproliferative activity in ovarian cancer cell lines in vitro. In the present study we evaluated the activity of the new compounds in human ovarian cancer xenografts. METHODS: Expression of Sp1 and target proteins in ovarian cancer specimens and tumor xenografts was assessed by immunohistochemistry. Drug-induced silencing of Sp1-regulated genes in cells and tumor xenograft samples was assessed by quantitative RT-PCR. Toxicity and antitumor activity of the compounds were investigated in healthy and tumor-bearing immunocompromised mice, respectively. RESULTS: Expression of Sp1 was frequently increased in human epithelial ovarian cancers. MTM-SDK and MTM-SK acted as potent inhibitors of Sp1-dependent transcription both in vitro and in tumor xenografts. Both compounds were well tolerated even after prolonged administration and delayed growth of ovarian tumor xenografts. MTM-SDK was particularly effective against orthotopic tumors leading to a significant increase of survival and delay of tumor progression. CONCLUSIONS: MTM-SDK and MTM-SK show relevant activity in vivo and represent interesting candidates for treatment of ovarian cancers.
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Antibióticos Antineoplásicos/farmacologia , Neoplasias Ovarianas/tratamento farmacológico , Plicamicina/análogos & derivados , Fator de Transcrição Sp1/antagonistas & inibidores , Animais , Processos de Crescimento Celular/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Plicamicina/farmacologia , Fator de Transcrição Sp1/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
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In this study, we extracted prostate cell-specific gene sets (metagenes) to define the epithelial differentiation status of prostate cancers and, using a deconvolution-based strategy, interrogated thousands of primary and metastatic tumors in public gene profiling datasets. We identified a subgroup of primary prostate tumors with low luminal epithelial enrichment (LumElow). LumElow tumors were associated with higher Gleason score and mutational burden, reduced relapse-free and overall survival, and were more likely to progress to castration-resistant prostate cancer (CRPC). Using discriminant function analysis, we generate a predictive 10-gene classifier for clinical implementation. This mini-classifier predicted with high accuracy the luminal status in both primary tumors and CRPCs. Immunohistochemistry for COL4A1, a low-luminal marker, sustained the association of attenuated luminal phenotype with metastatic disease. We found also an association of LumE score with tumor phenotype in genetically engineered mouse models (GEMMs) of prostate cancer. Notably, the metagene approach led to the discovery of drugs that could revert the low luminal status in prostate cell lines and mouse models. This study describes a novel tool to dissect the intrinsic heterogeneity of prostate tumors and provide predictive information on clinical outcome and treatment response in experimental and clinical samples.
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The emergence of therapy-resistant cancer stem cells (CSCs) limit the efficacy of prostate cancer treatment. Using genetic knockdown and chemical inhibitors, we demonstrate the critical role of Bromodomain Containing 4 (BRD4) in promoting mitochondrial fission and sustaining CSC expansion. These findings provide a new paradigm for developing novel treatment strategies for prostate cancer.
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BACKGROUND: The TMPRSS2-ERG gene fusion is the most frequent genetic rearrangement in prostate cancers and results in broad transcriptional reprogramming and major phenotypic changes. Interaction and cooperation of ERG and SP1 may be instrumental in sustaining the tumorigenic and metastatic phenotype and could represent a potential vulnerability in ERG fusion-positive tumors. OBJECTIVE: To test the activity of EC-8042, a compound able to block SP1, in cellular and mouse models of ERG-positive prostate cancer. DESIGN, SETTING, AND PARTICIPANTS: We evaluated the activity of EC-8042 in cell cultures and ERG/PTEN transgenic/knockout mice that provide reliable models for testing novel therapeutics in this specific disease context. Using a new protocol to generate tumor spheroids from ERG/PTEN mice, we also examined the effects of EC-8042 on tumor-propagating stem-like cancer cells with high self-renewal and tumorigenic capabilities. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The efficacy of EC-8042 was determined by measuring the proliferative capacity and target gene expression in cell cultures, invasive and metastatic capabilities in chick chorioallantoic membrane assays, and tumor development in mice. Significance was determined using statistical test. RESULTS AND LIMITATIONS: EC-8042 blocked transcription of ERG-regulated genes and reverted the invasive and metastatic phenotype of VCaP cells. EC-8042 blocked the expansion of stem-like tumor cells in tumor spheroids from VCaP cells and mouse-derived tumors. In ERG/PTEN mice, systemic treatment with EC-8042 inhibited ERG-regulated gene transcription, tumor progression, and tumor-propagating stem-like tumor cells. CONCLUSIONS: Our data support clinical testing of EC-8042 for the treatment of ERG-positive prostate cancer in precision medicine approaches. PATIENT SUMMARY: In this study, EC-8042, a novel compound with a favorable pharmacological and toxicological profile, exhibited relevant activity in cell cultures and in vivo in a genetically engineered mouse model that closely recapitulates the features of clinically aggressive ERG-positive prostate cancer. Our data indicate that further evaluation of EC-8042 in clinical trials is warranted.
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Plicamicina/análogos & derivados , Neoplasias da Próstata/genética , Fator de Transcrição Sp1/antagonistas & inibidores , Regulador Transcricional ERG/genética , Animais , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos Transgênicos , Células-Tronco Neoplásicas , PTEN Fosfo-Hidrolase/genética , Plicamicina/farmacologia , Plicamicina/uso terapêutico , Neoplasias da Próstata/tratamento farmacológicoRESUMO
Prostate cancer is the most common malignancy in men and the second cause of cancer-related deaths in western countries. Despite the progress in the treatment of localized prostate cancer, there is still lack of effective therapies for the advanced forms of the disease. Most patients with advanced prostate cancer become resistant to androgen deprivation therapy (ADT), which remains the main therapeutic option in this setting, and progress to lethal metastatic castration-resistant prostate cancer (mCRPC). Current therapies for prostate cancer preferentially target proliferating, partially differentiated, and AR-dependent cancer cells that constitute the bulk of the tumor mass. However, the subpopulation of tumor-initiating or tumor-propagating stem-like cancer cells is virtually resistant to the standard treatments causing tumor relapse at the primary or metastatic sites. Understanding the pathways controlling the establishment, expansion and maintenance of the cancer stem cell (CSC) subpopulation is an important step toward the development of more effective treatment for prostate cancer, which might enable ablation or exhaustion of CSCs and prevent treatment resistance and disease recurrence. In this review, we focus on the impact of transcriptional regulators on phenotypic reprogramming of prostate CSCs and provide examples supporting the possibility of inhibiting maintenance and expansion of the CSC pool in human prostate cancer along with the currently available methodological approaches. Transcription factors are key elements for instructing specific transcriptional programs and inducing CSC-associated phenotypic changes implicated in disease progression and treatment resistance. Recent studies have shown that interfering with these processes causes exhaustion of CSCs with loss of self-renewal and tumorigenic capability in prostate cancer models. Targeting key transcriptional regulators in prostate CSCs is a valid therapeutic strategy waiting to be tested in clinical trials.