RESUMEN
Castration resistant prostate cancer (CRPC) remains an incurable disease stage with ineffective treatments options. Here, the androgen receptor (AR) coactivators CBP/p300, which are histone acetyltransferases, were identified as critical mediators of DNA damage repair (DDR) to potentially enhance therapeutic targeting of CRPC. Key findings demonstrate that CBP/p300 expression increases with disease progression and selects for poor prognosis in metastatic disease. CBP/p300 bromodomain inhibition enhances response to standard of care therapeutics. Functional studies, CBP/p300 cistrome mapping, and transcriptome in CRPC revealed that CBP/p300 regulates DDR. Further mechanistic investigation showed that CBP/p300 attenuation via therapeutic targeting and genomic knockdown decreases homologous recombination (HR) factors in vitro, in vivo, and in human prostate cancer (PCa) tumors ex vivo. Similarly, CBP/p300 expression in human prostate tissue correlates with HR factors. Lastly, targeting CBP/p300 impacts HR-mediate repair and patient outcome. Collectively, these studies identify CBP/p300 as drivers of PCa tumorigenesis and lay the groundwork to optimize therapeutic strategies for advanced PCa via CBP/p300 inhibition, potentially in combination with AR-directed and DDR therapies.
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PARP is a nuclear enzyme with a major function in the DNA damage response. PARP inhibitors (PARPi) have been developed for treating tumors harboring homologous recombination repair defects that lead to a dependency on PARP. There are currently three PARPi approved for use in advanced prostate cancer, and several others are in clinical trials for this disease. Recent clinical trial results have reported differential efficacy based on the specific PARPi utilized as well as patient race. There is a racial disparity in prostate cancer, in which African American males are twice as likely to develop and die from the disease compared with European American males. Despite the disparity, there continues to be a lack of diversity in clinical trial cohorts for prostate cancer. In this review, PARP nuclear functions, inhibition, and clinical relevance are explored through the lens of racial differences. This review will touch on the biological variations that have been explored thus far between African American and European American males with prostate cancer to offer a rationale for investigating PARPi response in the context of race at both basic science and clinical development levels.
Asunto(s)
Inhibidores de Poli(ADP-Ribosa) Polimerasas , Neoplasias de la Próstata , Humanos , Masculino , Inhibidores de Poli(ADP-Ribosa) Polimerasas/uso terapéutico , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/etnología , Neoplasias de la Próstata/patología , Ensayos Clínicos como Asunto , Negro o Afroamericano/genética , Población Blanca/genética , Población Blanca/estadística & datos numéricos , Poli(ADP-Ribosa) Polimerasas/metabolismo , Poli(ADP-Ribosa) Polimerasas/genéticaRESUMEN
Lipid droplets (LD) are dynamic organelles that serve as hubs of cellular metabolic processes. Emerging evidence shows that LDs also play a critical role in maintaining redox homeostasis and can mitigate lipid oxidative stress. In multiple cancers, including prostate cancer, LD accumulation is associated with cancer aggressiveness, therapy resistance, and poor clinical outcome. Prostate cancer arises as an androgen receptor (AR)-driven disease. Among its myriad roles, AR mediates the biosynthesis of LDs, induces autophagy, and modulates cellular oxidative stress in a tightly regulated cycle that promotes cell proliferation. The factors regulating the interplay of these metabolic processes downstream of AR remain unclear. Here, we show that Sigma1/SIGMAR1, a unique ligand-operated scaffolding protein, regulates LD metabolism in prostate cancer cells. Sigma1 inhibition triggers lipophagy, an LD selective form of autophagy, to prevent accumulation of LDs which normally act to sequester toxic levels of reactive oxygen species (ROS). This disrupts the interplay between LDs, autophagy, buffering of oxidative stress and redox homeostasis, and results in the suppression of cell proliferation in vitro and tumor growth in vivo. Consistent with these experimental results, SIGMAR1 transcripts are strongly associated with lipid metabolism and ROS pathways in prostate tumors. Altogether, these data reveal a novel, pharmacologically responsive role for Sigma1 in regulating the redox homeostasis required by oncogenic metabolic programs that drive prostate cancer proliferation. SIGNIFICANCE: To proliferate, cancer cells must maintain productive metabolic and oxidative stress (eustress) while mitigating destructive, uncontrolled oxidative stress (distress). LDs are metabolic hubs that enable adaptive responses to promote eustress. Targeting the unique Sigma1 protein can trigger distress by disrupting the LD-mediated homeostasis required for proliferation.
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Gotas Lipídicas , Neoplasias de la Próstata , Masculino , Humanos , Gotas Lipídicas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Neoplasias de la Próstata/genética , Homeostasis/fisiología , Oxidación-ReducciónRESUMEN
Signaling rewiring allows tumors to survive therapy. Here we show that the decrease of the master regulator microphthalmia transcription factor (MITF) in lethal prostate cancer unleashes eukaryotic initiation factor 3B (eIF3B)-dependent translation reprogramming of key mRNAs conferring resistance to androgen deprivation therapy (ADT) and promoting immune evasion. Mechanistically, MITF represses through direct promoter binding eIF3B, which in turn regulates the translation of specific mRNAs. Genome-wide eIF3B enhanced cross-linking immunoprecipitation sequencing (eCLIP-seq) showed specialized binding to a UC-rich motif present in subsets of 5' untranslated regions. Indeed, translation of the androgen receptor and major histocompatibility complex I (MHC-I) through this motif is sensitive to eIF3B amount. Notably, pharmacologic targeting of eIF3B-dependent translation in preclinical models sensitizes prostate cancer to ADT and anti-PD-1 therapy. These findings uncover a hidden connection between transcriptional and translational rewiring promoting therapy-refractory lethal prostate cancer and provide a druggable mechanism that may transcend into effective combined therapeutic strategies. SIGNIFICANCE: Our study shows that specialized eIF3B-dependent translation of specific mRNAs released upon downregulation of the master transcription factor MITF confers castration resistance and immune evasion in lethal prostate cancer. Pharmacologic targeting of this mechanism delays castration resistance and increases immune-checkpoint efficacy. This article is featured in Selected Articles from This Issue, p. 2489.
Asunto(s)
Neoplasias de la Próstata Resistentes a la Castración , Neoplasias de la Próstata , Masculino , Humanos , Factores de Transcripción , Antagonistas de Andrógenos/farmacología , Antagonistas de Andrógenos/uso terapéutico , Evasión Inmune , Receptores Androgénicos/genética , Castración , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/genética , Neoplasias de la Próstata Resistentes a la Castración/patologíaRESUMEN
Prostate cancer (PCa) is the second leading cause of cancer death for men in the United States. While organ-confined disease has reasonable expectation of cure, metastatic PCa is universally fatal upon recurrence during hormone therapy, a stage termed castration-resistant prostate cancer (CRPC). Until such time as molecularly defined subtypes can be identified and targeted using precision medicine, it is necessary to investigate new therapies that may apply to the CRPC population as a whole. The administration of ascorbate, more commonly known as ascorbic acid or Vitamin C, has proved lethal to and highly selective for a variety of cancer cell types. There are several mechanisms currently under investigation to explain how ascorbate exerts anti-cancer effects. A simplified model depicts ascorbate as a pro-drug for reactive oxygen species (ROS), which accumulate intracellularly and generate DNA damage. It was therefore hypothesized that poly(ADP-ribose) polymerase (PARP) inhibitors, by inhibiting DNA damage repair, would augment the toxicity of ascorbate. Results: Two distinct CRPC models were found to be sensitive to physiologically relevant doses of ascorbate. Moreover, additional studies indicate that ascorbate inhibits CRPC growth in vitro via multiple mechanisms including disruption of cellular energy dynamics and accumulation of DNA damage. Combination studies were performed in CRPC models with ascorbate in conjunction with escalating doses of three different PARP inhibitors (niraparib, olaparib, and talazoparib). The addition of ascorbate augmented the toxicity of all three PARP inhibitors and proved synergistic with olaparib in both CRPC models. Finally, the combination of olaparib and ascorbate was tested in vivo in both castrated and non-castrated models. In both cohorts, the combination treatment significantly delayed tumor growth compared to monotherapy or untreated control. Conclusions: These data indicate that pharmacological ascorbate is an effective monotherapy at physiological concentrations and kills CRPC cells. Ascorbate-induced tumor cell death was associated with disruption of cellular energy dynamics and accumulation of DNA damage. The addition of PARP inhibition increased the extent of DNA damage and proved effective at slowing CRPC growth both in vitro and in vivo. These findings nominate ascorbate and PARPi as a novel therapeutic regimen that has the potential to improve CRPC patient outcomes.
RESUMEN
Metastatic prostate cancer (PCa) inevitably acquires resistance to standard therapy preceding lethality. Here, we unveil a chromosomal instability (CIN) tolerance mechanism as a therapeutic vulnerability of therapy-refractory lethal PCa. Through genomic and transcriptomic analysis of patient datasets, we find that castration and chemotherapy-resistant tumors display the highest CIN and mitotic kinase levels. Functional genomics screening coupled with quantitative phosphoproteomics identify MASTL kinase as a survival vulnerability specific of chemotherapy-resistant PCa cells. Mechanistically, MASTL upregulation is driven by transcriptional rewiring mechanisms involving the non-canonical transcription factors androgen receptor splice variant 7 and E2F7 in a circuitry that restrains deleterious CIN and prevents cell death selectively in metastatic therapy-resistant PCa cells. Notably, MASTL pharmacological inhibition re-sensitizes tumors to standard therapy and improves survival of pre-clinical models. These results uncover a targetable mechanism promoting high CIN adaptation and survival of lethal PCa.
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Neoplasias de la Próstata Resistentes a la Castración , Masculino , Humanos , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Neoplasias de la Próstata Resistentes a la Castración/patología , Receptores Androgénicos/genética , Receptores Androgénicos/metabolismo , Inestabilidad Cromosómica , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/uso terapéutico , Proteínas Serina-Treonina Quinasas/genéticaRESUMEN
Six-Transmembrane Epithelial Antigen of the Prostate 1-4 (STEAP1-4) compose a family of metalloproteinases involved in iron and copper homeostasis and other cellular processes. Thus far, five homologs are known: STEAP1, STEAP1B, STEAP2, STEAP3, and STEAP4. In prostate cancer, STEAP1, STEAP2, and STEAP4 are overexpressed, while STEAP3 expression is downregulated. Although the metalloreductase activities of STEAP1-4 are well documented, their other biological functions are not. Furthermore, the properties and expression levels of STEAP heterotrimers, homotrimers, heterodimers, and homodimers are not well understood. Nevertheless, studies over the last few decades have provided sufficient impetus to investigate STEAP1-4 as potential biomarkers and therapeutic targets for prostate cancer. In particular, STEAP1 is the target of many emerging immunotherapies. Herein, we give an overview of the structure, physiology, and pathophysiology of STEAP1-4 to provide context for past and current efforts to translate STEAP1-4 into the clinic.
RESUMEN
PURPOSE: DNA-dependent protein kinase catalytic subunit (DNA-PKcs, herein referred as DNA-PK) is a multifunctional kinase of high cancer relevance. DNA-PK is deregulated in multiple tumor types, including prostate cancer, and is associated with poor outcomes. DNA-PK was previously nominated as a therapeutic target and DNA-PK inhibitors are currently undergoing clinical investigation. Although DNA-PK is well studied in DNA repair and transcriptional regulation, much remains to be understood about the way by which DNA-PK drives aggressive disease phenotypes. EXPERIMENTAL DESIGN: Here, unbiased proteomic and metabolomic approaches in clinically relevant tumor models uncovered a novel role of DNA-PK in metabolic regulation of cancer progression. DNA-PK regulation of metabolism was interrogated using pharmacologic and genetic perturbation using in vitro cell models, in vivo xenografts, and ex vivo in patient-derived explants (PDE). RESULTS: Key findings reveal: (i) the first-in-field DNA-PK protein interactome; (ii) numerous DNA-PK novel partners involved in glycolysis; (iii) DNA-PK interacts with, phosphorylates (in vitro), and increases the enzymatic activity of glycolytic enzymes ALDOA and PKM2; (iv) DNA-PK drives synthesis of glucose-derived pyruvate and lactate; (v) DNA-PK regulates glycolysis in vitro, in vivo, and ex vivo; and (vi) combination of DNA-PK inhibitor with glycolytic inhibitor 2-deoxyglucose leads to additive anti-proliferative effects in aggressive disease. CONCLUSIONS: Findings herein unveil novel DNA-PK partners, substrates, and function in prostate cancer. DNA-PK impacts glycolysis through direct interaction with glycolytic enzymes and modulation of enzymatic activity. These events support energy production that may contribute to generation and/or maintenance of DNA-PK-mediated aggressive disease phenotypes.
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Proteína Quinasa Activada por ADN , Neoplasias de la Próstata Resistentes a la Castración , ADN , Proteína Quinasa Activada por ADN/genética , Proteína Quinasa Activada por ADN/metabolismo , Glucólisis , Humanos , Masculino , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/genética , Proteómica , Piruvato Quinasa/metabolismoRESUMEN
The tumor suppressor gene TP53 is the most frequently mutated gene in numerous cancer types, including prostate cancer (PCa). Specifically, missense mutations in TP53 are selectively enriched in PCa, and cluster to particular "hot spots" in the p53 DNA binding domain with mutation at the R273 residue occurring most frequently. While this residue is similarly mutated to R273C-p53 or R273H-p53 in all cancer types examined, in PCa selective enrichment of R273C-p53 is observed. Importantly, examination of clinical datasets indicated that TP53 heterozygosity can either be maintained or loss of heterozygosity (LOH) occurs. Thus, to mimic tumor-associated mutant p53, R273C-p53 and R273H-p53 isogenic PCa models were developed in the presence or absence of wild-type p53. In the absence of wild-type p53, both R273C-p53 and R273H-p53 exhibited similar loss of DNA binding, transcriptional profiles, and loss of canonical tumor suppressor functions associated with wild-type p53. In the presence of wild-type p53 expression, both R273C-p53 and R273H-p53 supported canonical p53 target gene expression yet elicited distinct cistromic and transcriptional profiles when compared to each other. Moreover, heterozygous modeling of R273C-p53 or R273H-p53 expression resulted in distinct phenotypic outcomes in vitro and in vivo. Thus, mutant p53 acts in a context-dependent manner to elicit pro-tumorigenic transcriptional profiles, providing critical insight into mutant p53-mediated prostate cancer progression.
Asunto(s)
Carcinogénesis/genética , Neoplasias de la Próstata/genética , Proteína p53 Supresora de Tumor/metabolismo , Humanos , Masculino , FenotipoRESUMEN
The retinoblastoma tumor suppressor (RB) is a critical regulator of E2F-dependent transcription, controlling a multitude of protumorigenic networks including but not limited to cell-cycle control. Here, genome-wide assessment of E2F1 function after RB loss in isogenic models of prostate cancer revealed unexpected repositioning and cooperation with oncogenic transcription factors, including the major driver of disease progression, the androgen receptor (AR). Further investigation revealed that observed AR/E2F1 cooperation elicited novel transcriptional networks that promote cancer phenotypes, especially as related to evasion of cell death. These observations were reflected in assessment of human disease, indicating the clinical relevance of the AR/E2F1 cooperome in prostate cancer. Together, these studies reveal new mechanisms by which RB loss induces cancer progression and highlight the importance of understanding the targets of E2F1 function. SIGNIFICANCE: This study identifies that RB loss in prostate cancer drives cooperation between AR and E2F1 as coregulators of transcription, which is linked to the progression of advanced disease.
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Carcinogénesis/genética , Factor de Transcripción E2F1/metabolismo , Proteínas Oncogénicas/metabolismo , Neoplasias de la Próstata/metabolismo , Receptores Androgénicos/metabolismo , Proteínas de Unión a Retinoblastoma/metabolismo , Transducción de Señal/genética , Ubiquitina-Proteína Ligasas/metabolismo , Apoptosis/genética , Sitios de Unión , Línea Celular Tumoral , Supervivencia Celular/genética , Estudios de Cohortes , Factor de Transcripción E2F1/genética , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Masculino , Proteínas Oncogénicas/genética , Oncogenes , Neoplasias de la Próstata/patología , Unión Proteica/genética , Proteínas de Unión a Retinoblastoma/genética , Transfección , Ubiquitina-Proteína Ligasas/genéticaRESUMEN
Androgen receptor function, tumor cell plasticity, loss of tumor suppressors, and defects in DNA repair genes affect aggressive features of prostate cancer. Prostate cancer development, progression, and aggressive behavior are often attributable to function of the androgen receptor. Tumor cell plasticity, neuroendocrine features, and loss of tumor suppressors lend aggressive behavior to prostate cancer cells. DNA repair defects have ramifications for prostate cancer cell behavior.
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Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Receptores Androgénicos/genética , Antagonistas de Andrógenos/uso terapéutico , Biomarcadores de Tumor/genética , Plasticidad de la Célula , Reparación del ADN , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica , Pruebas Genéticas , Mutación de Línea Germinal , Humanos , Masculino , Medicina de Precisión , Antígeno Prostático Específico/sangre , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/genética , Neoplasias de la Próstata Resistentes a la Castración/patologíaRESUMEN
Loss of the retinoblastoma (RB) tumor suppressor protein is a critical step in reprogramming biological networks that drive cancer progression, although mechanistic insight has been largely limited to the impact of RB loss on cell-cycle regulation. Here, isogenic modeling of RB loss identified disease stage-specific rewiring of E2F1 function, providing the first-in-field mapping of the E2F1 cistrome and transcriptome after RB loss across disease progression. Biochemical and functional assessment using both in vitro and in vivo models identified an unexpected, prominent role for E2F1 in regulation of redox metabolism after RB loss, driving an increase in the synthesis of the antioxidant glutathione, specific to advanced disease. These E2F1-dependent events resulted in protection from reactive oxygen species in response to therapeutic intervention. On balance, these findings reveal novel pathways through which RB loss promotes cancer progression and highlight potentially new nodes of intervention for treating RB-deficient cancers. SIGNIFICANCE: This study identifies stage-specific consequences of RB loss across cancer progression that have a direct impact on tumor response to clinically utilized therapeutics. The study herein is the first to investigate the effect of RB loss on global metabolic regulation and link RB/E2F1 to redox control in multiple advanced diseases.This article is highlighted in the In This Issue feature, p. 2113.
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Factor de Transcripción E2F1/genética , Neoplasias de la Retina/genética , Proteína de Retinoblastoma/genética , Retinoblastoma/genética , Animales , Línea Celular Tumoral , Humanos , Ratones , Metástasis de la Neoplasia , Neoplasias de la Retina/patología , Retinoblastoma/secundario , Transducción de Señal , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Mechanisms regulating DNA repair processes remain incompletely defined. Here, the circadian factor CRY1, an evolutionally conserved transcriptional coregulator, is identified as a tumor specific regulator of DNA repair. Key findings demonstrate that CRY1 expression is androgen-responsive and associates with poor outcome in prostate cancer. Functional studies and first-in-field mapping of the CRY1 cistrome and transcriptome reveal that CRY1 regulates DNA repair and the G2/M transition. DNA damage stabilizes CRY1 in cancer (in vitro, in vivo, and human tumors ex vivo), which proves critical for efficient DNA repair. Further mechanistic investigation shows that stabilized CRY1 temporally regulates expression of genes required for homologous recombination. Collectively, these findings reveal that CRY1 is hormone-induced in tumors, is further stabilized by genomic insult, and promotes DNA repair and cell survival through temporal transcriptional regulation. These studies identify the circadian factor CRY1 as pro-tumorigenic and nominate CRY1 as a new therapeutic target.
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Carcinogénesis/genética , Criptocromos/metabolismo , Regulación Neoplásica de la Expresión Génica , Neoplasias de la Próstata Resistentes a la Castración/genética , Reparación del ADN por Recombinación/genética , Anciano , Antagonistas de Receptores Androgénicos/farmacología , Antagonistas de Receptores Androgénicos/uso terapéutico , Andrógenos/metabolismo , Carcinogénesis/efectos de los fármacos , Línea Celular Tumoral , Secuenciación de Inmunoprecipitación de Cromatina , Criptocromos/genética , Roturas del ADN de Doble Cadena/efectos de los fármacos , Conjuntos de Datos como Asunto , Progresión de la Enfermedad , Estudios de Seguimiento , Puntos de Control de la Fase G2 del Ciclo Celular/genética , Humanos , Masculino , Persona de Mediana Edad , Clasificación del Tumor , Regiones Promotoras Genéticas/genética , Estudios Prospectivos , Próstata/patología , Próstata/cirugía , Prostatectomía , Neoplasias de la Próstata Resistentes a la Castración/mortalidad , Neoplasias de la Próstata Resistentes a la Castración/patología , Neoplasias de la Próstata Resistentes a la Castración/terapia , RNA-Seq , Receptores Androgénicos/metabolismo , Reparación del ADN por Recombinación/efectos de los fármacos , Estudios RetrospectivosRESUMEN
Resistance to androgen receptor (AR) blockade in castration-resistant prostate cancer (CRPC) is associated with sustained AR signaling, including through alternative splicing of AR (AR-SV). Inhibitors of transcriptional coactivators that regulate AR activity, including the paralog histone acetyltransferase proteins p300 and CBP, are attractive therapeutic targets for lethal prostate cancer. Herein, we validate targeting p300/CBP as a therapeutic strategy for lethal prostate cancer and describe CCS1477, a novel small-molecule inhibitor of the p300/CBP conserved bromodomain. We show that CCS1477 inhibits cell proliferation in prostate cancer cell lines and decreases AR- and C-MYC-regulated gene expression. In AR-SV-driven models, CCS1477 has antitumor activity, regulating AR and C-MYC signaling. Early clinical studies suggest that CCS1477 modulates KLK3 blood levels and regulates CRPC biopsy biomarker expression. Overall, CCS1477 shows promise for the treatment of patients with advanced prostate cancer. SIGNIFICANCE: Treating CRPC remains challenging due to persistent AR signaling. Inhibiting transcriptional AR coactivators is an attractive therapeutic strategy. CCS1477, an inhibitor of p300/CBP, inhibits growth and AR activity in CRPC models, and can affect metastatic CRPC target expression in serial clinical biopsies.See related commentary by Rasool et al., p. 1011.This article is highlighted in the In This Issue feature, p. 995.
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Antagonistas de Receptores Androgénicos/uso terapéutico , Imidazoles/uso terapéutico , Oxazoles/uso terapéutico , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Factores de Transcripción p300-CBP/antagonistas & inhibidores , Antagonistas de Receptores Androgénicos/farmacología , Animales , Línea Celular Tumoral/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Humanos , Imidazoles/farmacología , Masculino , Ratones , Oxazoles/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Emerging evidence indicates the deubiquitinase USP22 regulates transcriptional activation and modification of target substrates to promote pro-oncogenic phenotypes. Here, in vivo characterization of tumor-associated USP22 upregulation and unbiased interrogation of USP22-regulated functions in vitro demonstrated critical roles for USP22 in prostate cancer. Specifically, clinical datasets validated that USP22 expression is elevated in prostate cancer, and a novel murine model demonstrated a hyperproliferative phenotype with prostate-specific USP22 overexpression. Accordingly, upon overexpression or depletion of USP22, enrichment of cell-cycle and DNA repair pathways was observed in the USP22-sensitive transcriptome and ubiquitylome using prostate cancer models of clinical relevance. Depletion of USP22 sensitized cells to genotoxic insult, and the role of USP22 in response to genotoxic insult was further confirmed using mouse adult fibroblasts from the novel murine model of USP22 expression. As it was hypothesized that USP22 deubiquitylates target substrates to promote protumorigenic phenotypes, analysis of the USP22-sensitive ubiquitylome identified the nucleotide excision repair protein, XPC, as a critical mediator of the USP22-mediated response to genotoxic insult. Thus, XPC undergoes deubiquitylation as a result of USP22 function and promotes USP22-mediated survival to DNA damage. Combined, these findings reveal unexpected functions of USP22 as a driver of protumorigenic phenotypes and have significant implications for the role of USP22 in therapeutic outcomes. SIGNIFICANCE: The studies herein present a novel mouse model of tumor-associated USP22 overexpression and implicate USP22 in modulation of cellular survival and DNA repair, in part through regulation of XPC.
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Carcinogénesis/patología , Proliferación Celular , Enzimas Reparadoras del ADN/metabolismo , Reparación del ADN , Regulación Neoplásica de la Expresión Génica , Neoplasias de la Próstata/patología , Ubiquitina Tiolesterasa/metabolismo , Animales , Apoptosis , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Carcinogénesis/genética , Carcinogénesis/metabolismo , Daño del ADN , Enzimas Reparadoras del ADN/genética , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Pronóstico , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Células Tumorales Cultivadas , Ubiquitina Tiolesterasa/genética , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
PURPOSE: DNA-dependent protein kinase catalytic subunit (DNA-PK) is a pleiotropic kinase involved in DNA repair and transcriptional regulation. DNA-PK is deregulated in selected cancer types and is strongly associated with poor outcome. The underlying mechanisms by which DNA-PK promotes aggressive tumor phenotypes are not well understood. Here, unbiased molecular investigation in clinically relevant tumor models reveals novel functions of DNA-PK in cancer.Experimental Design: DNA-PK function was modulated using both genetic and pharmacologic methods in a series of in vitro models, in vivo xenografts, and patient-derived explants (PDE), and the impact on the downstream signaling and cellular cancer phenotypes was discerned. Data obtained were used to develop novel strategies for combinatorial targeting of DNA-PK and hormone signaling pathways. RESULTS: Key findings reveal that (i) DNA-PK regulates tumor cell proliferation; (ii) pharmacologic targeting of DNA-PK suppresses tumor growth both in vitro, in vivo, and ex vivo; (iii) DNA-PK transcriptionally regulates the known DNA-PK-mediated functions as well as novel cancer-related pathways that promote tumor growth; (iv) dual targeting of DNA-PK/TOR kinase (TORK) transcriptionally upregulates androgen signaling, which can be mitigated using the androgen receptor (AR) antagonist enzalutamide; (v) cotargeting AR and DNA-PK/TORK leads to the expansion of antitumor effects, uncovering the modulation of novel, highly relevant protumorigenic cancer pathways; and (viii) cotargeting DNA-PK/TORK and AR has cooperative growth inhibitory effects in vitro and in vivo. CONCLUSIONS: These findings uncovered novel DNA-PK transcriptional regulatory functions and led to the development of a combinatorial therapeutic strategy for patients with advanced prostate cancer, currently being tested in the clinical setting.
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Proteína Quinasa Activada por ADN/metabolismo , Neoplasias/metabolismo , Antagonistas de Receptores Androgénicos/farmacología , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Biomarcadores de Tumor , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Proteína Quinasa Activada por ADN/antagonistas & inhibidores , Proteína Quinasa Activada por ADN/genética , Modelos Animales de Enfermedad , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Masculino , Ratones , Terapia Molecular Dirigida , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Receptores Androgénicos/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Transcripción Genética , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Prostatic adenocarcinoma (PCa) remains a significant health concern. Although localized PCa can be effectively treated, disseminated disease remains uniformly fatal. PCa is reliant on androgen receptor (AR); as such, first-line therapy for metastatic PCa entails suppression of AR signaling. Although initially effective, recurrent tumors reactivate AR function, leading to a lethal stage of disease termed castration-resistant PCa (CRPC). Recent findings implicate AR signaling in control of DNA repair and show that alterations in DNA damage repair pathways are strongly associated with disease progression and poor outcome. This review will address the DNA repair alterations observed in the clinical setting, explore the anticipated molecular and cellular consequence of DNA repair dysfunction, and consider clinical strategies for targeting tumors with altered DNA repair.
Asunto(s)
Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Transformación Celular Neoplásica/metabolismo , Daño del ADN , Reparación del ADN , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Adenocarcinoma/tratamiento farmacológico , Antagonistas de Receptores Androgénicos/metabolismo , Antagonistas de Receptores Androgénicos/uso terapéutico , Transformación Celular Neoplásica/genética , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Neoplasias de la Próstata/tratamiento farmacológico , Reparación del Gen Blanco/métodosRESUMEN
BACKGROUND: Androgen deprivation therapy is a first-line treatment for disseminated prostate cancer (PCa). However, virtually all tumors become resistant and recur as castration-resistant PCa, which has no durable cure. One major hurdle in the development of more effective therapies is the lack of preclinical models that adequately recapitulate the heterogeneity of PCa, significantly hindering the ability to accurately predict therapeutic response. OBJECTIVE: To leverage the ex vivo culture method termed patient-derived explant (PDE) to examine the impact of PCa therapeutics on a patient-by-patient basis. DESIGN SETTING AND PARTICIPANTS: Fresh PCa tissue from patients who underwent radical prostatectomy was cultured as PDEs to examine therapeutic response. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The impact of genomic and chemical perturbations in PDEs was assessed using various parameters (eg, AR levels, Ki67 staining, and desmoplastic indices). RESULTS AND LIMITATIONS: PDE maintained the integrity of the native tumor microenvironment (TME), tumor tissue morphology, viability, and endogenous hormone signaling. Tumor cells in this model system exhibited de novo proliferative capacity. Examination of the native TME in the PDE revealed a first-in-field insight into patient-specific desmoplastic stromal indices and predicted responsiveness to AR-directed therapeutics. CONCLUSIONS: The PDE model allows for a comprehensive evaluation of individual tumors in their native TME to ultimately develop more effective therapeutic regimens tailored to individuals. Discernment of novel stromal markers may provide a basis for applying precision medicine in treating advanced PCa, which would have a transformative effect on patient outcomes. PATIENT SUMMARY: In this study, an innovative model system was used to more effectively mimic human disease. The patient-derived explant (PDE) system can be used to predict therapeutic response and identify novel targets in advanced disease. Thus, the PDE will be an asset for the development of novel metrics for the implementation of precision medicine in prostate cancer.The patient-derived explant (PDE) model allows for a comprehensive evaluation of individual human tumors in their native tumor microenvironment (TME). TME analysis revealed first-in-field insight into predicted tumor responsiveness to AR-directed therapeutics through evaluation of patient-specific desmoplastic stromal indices.
RESUMEN
PARP-1 holds major functions on chromatin, DNA damage repair and transcriptional regulation, both of which are relevant in the context of cancer. Here, unbiased transcriptional profiling revealed the downstream transcriptional profile of PARP-1 enzymatic activity. Further investigation of the PARP-1-regulated transcriptome and secondary strategies for assessing PARP-1 activity in patient tissues revealed that PARP-1 activity was unexpectedly enriched as a function of disease progression and was associated with poor outcome independent of DNA double-strand breaks, suggesting that enhanced PARP-1 activity may promote aggressive phenotypes. Mechanistic investigation revealed that active PARP-1 served to enhance E2F1 transcription factor activity, and specifically promoted E2F1-mediated induction of DNA repair factors involved in homologous recombination (HR). Conversely, PARP-1 inhibition reduced HR factor availability and thus acted to induce or enhance "BRCA-ness". These observations bring new understanding of PARP-1 function in cancer and have significant ramifications on predicting PARP-1 inhibitor function in the clinical setting.
Asunto(s)
Reparación del ADN , Factor de Transcripción E2F1/metabolismo , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Neoplasias de la Próstata/patología , Animales , Línea Celular , Progresión de la Enfermedad , Perfilación de la Expresión Génica , Recombinación Homóloga , Humanos , Inmunohistoquímica , Masculino , Ratones Endogámicos BALB C , Análisis de Matrices TisularesRESUMEN
Breast and prostate cancer research to date has largely been predicated on the use of cell lines in vitro or in vivo. These limitations have led to the development of more clinically relevant models, such as organoids or murine xenografts that utilize patient-derived material; however, issues related to low take rate, long duration of establishment, and the associated costs constrain use of these models. This study demonstrates that ex vivo culture of freshly resected breast and prostate tumor specimens obtained from surgery, termed patient-derived explants (PDEs), provides a high-throughput and cost-effective model that retains the native tissue architecture, microenvironment, cell viability, and key oncogenic drivers. The PDE model provides a unique approach for direct evaluation of drug responses on an individual patient's tumor, which is amenable to analysis using contemporary genomic technologies. The ability to rapidly evaluate drug efficacy in patient-derived material has high potential to facilitate implementation of personalized medicine approaches.