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Despite the widespread deregulation of CDK4/6 activity in non-small cell lung cancer (NSCLC), the clinical trials with CDK4/6 inhibitors (CDK4/6is) as a monotherapy have shown poor antitumor activity. However, our preclinical studies have revealed a significant potential for CDK4/6is to collaborate by influencing DNA damage repair pathways during radiotherapy. Given the considerable upregulation of PARP1 expression in NSCLC, we analyzed the efficacy of combined PARP and CDK4/6 inhibition in NSCLC models. Our findings demonstrate that CDK4/6is synergize with PARP inhibitors (PARPis) to inhibit the clonogenic growth of RB-proficient NSCLC models. This synergy is associated with increased accumulation of DNA damage, interrupted cell-cycle checkpoints, and enhanced apoptotic cell death. We showed that CDK4/6is mechanically promote PARP1 protein degradation, leading to decreased availability of DNA repair factors involved in homologous recombination and suppression of DNA repair competency. Furthermore, we showed that PARP trapping is required for this synergy. We then confirmed that combining PARPi and CDK4/6i blocked the growth of NSCLC xenografts in vivo and patient-derived explant models ex vivo. These findings reveal a previously uncharacterized impact of CDK4/6i on PARP1 levels in RB-proficient NSCLC models and the requirement of PARP trapping to render synergy between CDK4/6i and PARPi. Our research suggests that combining CDK4/6i with PARPi could be a promising therapeutic strategy for patients with RB-proficient NSCLC, potentially opening up new and more effective avenues for treatment.
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The oligo-benzamide scaffold is a rigid organic framework that can hold 2-3 functional groups as O-alkyl substituents on its benzamide units, mirroring their natural arrangement in an α-helix. Oligo-benzamides demonstrated outstanding α-helix mimicry and can be readily synthesized by following high yielding and iterative reaction steps in both solution-phase and solid-phase. A number of oligo-benzamides have been designed to emulate α-helical peptide segments in biologically active proteins and showed strong protein binding, in turn effectively disrupting protein-protein interactions in vitro and in vivo. In this chapter, the design of oligo-benzamides for mimicking α-helices, efficient synthetic routes for producing them, and their biomedical studies showing remarkable potency in inhibiting protein functions are discussed.
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Benzamidas , Benzamidas/química , Benzamidas/farmacologia , Humanos , Peptídeos/química , Conformação Proteica em alfa-Hélice , Ligação Proteica , AnimaisRESUMO
Cancer cells exhibit phenotypical plasticity and epigenetic reprogramming that allows them to evade lineage-dependent targeted treatments by adopting lineage plasticity. The underlying mechanisms by which cancer cells exploit the epigenetic regulatory machinery to acquire lineage plasticity and therapy resistance remain poorly understood. We identified zinc finger protein 397 (ZNF397) as a bona fide coactivator of the androgen receptor (AR), essential for the transcriptional program governing AR-driven luminal lineage. ZNF397 deficiency facilitates the transition of cancer cell from an AR-driven luminal lineage to a ten-eleven translocation 2 (TET2)-driven lineage plastic state, ultimately promoting resistance to therapies inhibiting AR signaling. Intriguingly, our findings indicate that a TET2 inhibitor can eliminate the resistance to AR-targeted therapies in ZNF397-deficient tumors. These insights uncover a novel mechanism through which prostate cancer acquires lineage plasticity via epigenetic rewiring and offer promising implications for clinical interventions designed to overcome therapy resistance dictated by lineage plasticity. Significance: This study reveals a bifurcated role of ZNF397, and a TET2-driven epigenetic mechanism regulating tumor lineage plasticity and therapy response in prostate cancer, enhances the understanding of drug resistance, and unveils a new therapeutic strategy for overcoming androgen receptor-targeted therapy resistance.
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Proteínas de Ligação a DNA , Dioxigenases , Resistencia a Medicamentos Antineoplásicos , Neoplasias da Próstata , Receptores Androgênicos , Masculino , Humanos , Proteínas de Ligação a DNA/genética , Receptores Androgênicos/metabolismo , Receptores Androgênicos/genética , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Neoplasias da Próstata/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Camundongos , Animais , Linhagem Celular Tumoral , Epigênese Genética , Linhagem da CélulaRESUMO
Prostate cancer (PCa) is primarily driven by aberrant Androgen Receptor (AR) signaling. Although there has been substantial advancement in antiandrogen therapies, resistance to these treatments remains a significant obstacle, often marked by continuous or enhanced AR signaling in resistant tumors. While the dysregulation of the ubiquitination-based protein degradation process is instrumental in the accumulation of oncogenic proteins, including AR, the molecular mechanism of ubiquitination-driven AR degradation remains largely undefined. We identified UBE2J1 as the critical E2 ubiquitin-conjugating enzyme responsible for guiding AR ubiquitination and eventual degradation. The absence of UBE2J1, found in 5-15% of PCa patients, results in disrupted AR ubiquitination and degradation. This disruption leads to an accumulation of AR proteins, promoting resistance to antiandrogen treatments. By employing a ubiquitination-based AR degrader to adeptly restore AR ubiquitination, we reestablished AR degradation and inhibited the proliferation of antiandrogen-resistant PCa tumors. These findings underscore the fundamental role of UBE2J1 in AR degradation and illuminate an uncharted mechanism through which PCa maintains heightened AR protein levels, fostering resistance to antiandrogen therapies.
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Neoplasias de Próstata Resistentes à Castração , Neoplasias da Próstata , Proteólise , Receptores Androgênicos , Enzimas de Conjugação de Ubiquitina , Humanos , Masculino , Antagonistas de Androgênios/farmacologia , Androgênios , Linhagem Celular Tumoral , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/metabolismo , Receptores Androgênicos/metabolismo , Enzimas de Conjugação de Ubiquitina/genética , Enzimas de Conjugação de Ubiquitina/metabolismoRESUMO
Background: Resistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancer remains a significant clinical problem. Riluzole is FDA-approved for the treatment of amyotrophic lateral sclerosis. A benzothiazole-based glutamate release inhibitor with several context-dependent mechanism(s) of action, riluzole has shown antitumor activity in multiple malignancies, including melanoma, glioblastoma, and breast cancer. We previously reported that the acquisition of tamoxifen resistance in a cellular model of invasive lobular breast cancer is accompanied by the upregulation of GRM mRNA expression and growth inhibition by riluzole. Methods: We tested the ability of riluzole to reduce cell growth, alone and in combination with endocrine therapy, in a diverse set of ER+ invasive ductal and lobular breast cancer-derived cell lines, primary breast tumor explant cultures, and the estrogen-independent, ESR1-mutated invasive lobular breast cancer patient-derived xenograft model HCI-013EI. Results: Single-agent riluzole suppressed the growth of ER+ invasive ductal and lobular breast cancer cell lines in vitro, inducing a histologic subtype-associated cell cycle arrest (G0-G1 for ductal, G2-M for lobular). Riluzole induced apoptosis and ferroptosis and reduced phosphorylation of multiple prosurvival signaling molecules, including Akt/mTOR, CREB, and Fak/Src family kinases. Riluzole, in combination with either fulvestrant or 4-hydroxytamoxifen, additively suppressed ER+ breast cancer cell growth in vitro. Single-agent riluzole significantly inhibited HCI-013EI patient-derived xenograft growth in vivo, and the combination of riluzole plus fulvestrant significantly reduced proliferation in ex vivo primary breast tumor explant cultures. Conclusion: Riluzole may offer therapeutic benefits in diverse ER+ breast cancers, including lobular breast cancer.
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Transposable elements hold regulatory functions that impact cell fate determination by controlling gene expression. However, little is known about the transcriptional machinery engaged at transposable elements in pluripotent and mature versus oncogenic cell states. Through positional analysis over repetitive DNA sequences of H3K27ac chromatin immunoprecipitation sequencing data from 32 normal cell states, we report pluripotent/stem and mature cell state-specific "regulatory transposable elements." Pluripotent/stem elements are binding sites for pluripotency factors (e.g., NANOG, SOX2, OCT4). Mature cell elements are docking sites for lineage-specific transcription factors, including AR and FOXA1 in prostate epithelium. Expanding the analysis to prostate tumors, we identify a subset of regulatory transposable elements shared with pluripotent/stem cells, including Tigger3a. Using chromatin editing technology, we show how such elements promote prostate cancer growth by regulating AR transcriptional activity. Collectively, our results suggest that oncogenesis arises from lineage-specific transcription factors hijacking pluripotent/stem cell regulatory transposable elements. SIGNIFICANCE: We show that oncogenesis relies on co-opting transposable elements from pluripotent stem cells as regulatory elements altering the recruitment of lineage-specific transcription factors. We further discover how co-option is dependent on active chromatin states with important implications for developing treatment options against drivers of oncogenesis across the repetitive DNA. This article is featured in Selected Articles from This Issue, p. 2293.
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Neoplasias da Próstata , Fatores de Transcrição , Masculino , Humanos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Elementos de DNA Transponíveis/genética , Diferenciação Celular , Cromatina/genética , Neoplasias da Próstata/genética , Carcinogênese/genéticaRESUMO
Therapy resistance to second-generation androgen receptor (AR) antagonists, such as enzalutamide, is common in patients with advanced prostate cancer (PCa). To understand the metabolic alterations involved in enzalutamide resistance, we performed metabolomic, transcriptomic, and cistromic analyses of enzalutamide-sensitive and -resistant PCa cells, xenografts, patient-derived organoids, patient-derived explants, and tumors. We noted dramatically higher basal and inducible levels of reactive oxygen species (ROS) in enzalutamide-resistant PCa and castration-resistant PCa (CRPC), in comparison to enzalutamide-sensitive PCa cells or primary therapy-naive tumors respectively. Unbiased metabolomic evaluation identified that glutamine metabolism was consistently upregulated in enzalutamide-resistant PCa cells and CRPC tumors. Stable isotope tracing studies suggest that this enhanced glutamine metabolism drives an antioxidant program that allows these cells to tolerate higher basal levels of ROS. Inhibition of glutamine metabolism with either a small-molecule glutaminase inhibitor or genetic knockout of glutaminase enhanced ROS levels, and blocked the growth of enzalutamide-resistant PCa. The critical role of compensatory antioxidant pathways in maintaining enzalutamide-resistant PCa cells was validated by targeting another antioxidant program driver, ferredoxin 1. Taken together, our data identify a metabolic need to maintain antioxidant programs and a potentially targetable metabolic vulnerability in enzalutamide-resistant PCa.
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Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/metabolismo , Receptores Androgênicos/genética , Antioxidantes/farmacologia , Glutaminase , Glutamina , Espécies Reativas de Oxigênio , Resistencia a Medicamentos Antineoplásicos/genética , Nitrilas , Antagonistas de Receptores de Andrógenos/farmacologia , Linhagem Celular TumoralRESUMO
INTRODUCTION: Prostate cancer is the most common solid organ malignancy in men in the United States. Until recently, treatment options for men with metastatic disease were limited and patients faced poor outcomes with minimal alternatives. The landscape of prostate cancer treatment has transformed and taken shape over the last 20 years with novel hormonal and non-hormonal therapeutics that have demonstrated significant improvement in survival. However, patients with advanced disease still face imminent progression on hormone blockade therapy. AREAS COVERED: There is a significant market opportunity to devise novel, more potent agents for patients with hormone-resistant disease. Here we review the existing treatment options in men with advanced prostate cancer, the market opportunity within this field, goals of current research, and the novel agents under investigation, including androgen receptor degraders, testosterone synthesis pathway inhibitors, DNA-binding domain and N-terminal domain antagonists, and the combination of hormonal and non-hormonal agents. EXPERT OPINION: Combination therapy regimens and novel agents targeting alternative binding domains of the androgen receptor are of great interest, as they may overcome resistance mechanisms and hold promise as the future of advanced prostate cancer treatment.
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Neoplasias de Próstata Resistentes à Castração , Neoplasias da Próstata , Masculino , Humanos , Receptores Androgênicos , Antagonistas de Androgênios/farmacologia , Antagonistas de Androgênios/uso terapêutico , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Hormônios , Neoplasias de Próstata Resistentes à Castração/patologiaRESUMO
Prostate cancer (PCa) is one of the leading causes of cancer diagnoses and cancer-related deaths in the United States. Mutations or deletions in the genes involved in the DNA damage response (DDR) are common in aggressive primary PCa (germline alterations) and further enriched in advanced therapy-resistant PCa (somatic alterations). Among the DDR genes, BRCA2 is the most commonly altered (~ 13%) in advanced therapy-resistant PCa. Patients with BRCA2-altered PCas are exquisitely sensitive to poly (ADP-ribose) polymerase (PARP) inhibitors (PARPis). Indeed, two PARPis-olaparib and rucaparib have recently gained U.S. Food & Drug Administration approval for the treatment of advanced PCas harboring a BRCA2 mutation. This review seeks to explore the role of BRCA2 in DNA damage repair, the pathogenesis and progression of BRCA2 mutant PCa, and the utility of radiation therapy, targeted therapies, and platinum-based chemotherapies for patients with BRCA2 alterations.
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Genes BRCA2 , Neoplasias da Próstata , Proteína BRCA2/genética , Reparo do DNA/genética , Humanos , Masculino , Mutação , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genéticaRESUMO
Most patients with estrogen receptor alpha-positive (ER+) breast cancers initially respond to treatment but eventually develop therapy resistance with disease progression. Overexpression of oncogenic ER coregulators, including proline, glutamic acid, and leucine-rich protein 1 (PELP1), are implicated in breast cancer progression. The lack of small molecules that inhibits PELP1 represents a major knowledge gap. Here, using a yeast-two-hybrid screen, we identified novel peptide inhibitors of PELP1 (PIP). Biochemical assays demonstrated that one of these peptides, PIP1, directly interacted with PELP1 to block PELP1 oncogenic functions. Computational modeling of PIP1 revealed key residues contributing to its activity and facilitated the development of a small-molecule inhibitor of PELP1, SMIP34, and further analyses confirmed that SMIP34 directly bound to PELP1. In breast cancer cells, SMIP34 reduced cell growth in a dose-dependent manner. SMIP34 inhibited proliferation of not only wild-type (WT) but also mutant (MT) ER+ and therapy-resistant breast cancer cells, in part by inducing PELP1 degradation via the proteasome pathway. RNA sequencing analyses showed that SMIP34 treatment altered the expression of genes associated with estrogen response, cell cycle, and apoptosis pathways. In cell line-derived and patient-derived xenografts of both WT and MT ER+ breast cancer models, SMIP34 reduced proliferation and significantly suppressed tumor progression. Collectively, these results demonstrate SMIP34 as a first-in-class inhibitor of oncogenic PELP1 signaling in advanced breast cancer. SIGNIFICANCE: Development of a novel inhibitor of oncogenic PELP1 provides potential therapeutic avenues for treating therapy-resistant, advanced ER+ breast cancer.
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Neoplasias da Mama , Proteínas Correpressoras , Fatores de Transcrição , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Proteínas Correpressoras/antagonistas & inibidores , Proteínas Correpressoras/metabolismo , Receptor alfa de Estrogênio/genética , Estrogênios , Feminino , Ácido Glutâmico , Humanos , Leucina , Prolina , Complexo de Endopeptidases do Proteassoma , Receptores de Estrogênio/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismoRESUMO
Acquired mutations in the ligand-binding domain (LBD) of the gene encoding estrogen receptor α (ESR1) are common mechanisms of endocrine therapy resistance in patients with metastatic ER+ breast cancer. The ESR1 Y537S mutation, in particular, is associated with development of resistance to most endocrine therapies used to treat breast cancer. Employing a high-throughput screen of nearly 1,200 Federal Drug Administration-approved (FDA-approved) drugs, we show that OTX015, a bromodomain and extraterminal domain (BET) inhibitor, is one of the top suppressors of ESR1 mutant cell growth. OTX015 was more efficacious than fulvestrant, a selective ER degrader, in inhibiting ESR1 mutant xenograft growth. When combined with abemaciclib, a CDK4/6 inhibitor, OTX015 induced more potent tumor regression than current standard-of-care treatment of abemaciclib + fulvestrant. OTX015 has preferential activity against Y537S mutant breast cancer cells and blocks their clonal selection in competition studies with WT cells. Thus, BET inhibition has the potential to both prevent and overcome ESR1 mutant-induced endocrine therapy resistance in breast cancer.
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Neoplasias da Mama , Receptor alfa de Estrogênio/genética , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Proliferação de Células , Feminino , Fulvestranto/farmacologia , Fulvestranto/uso terapêutico , Humanos , Mutação , Domínios Proteicos , Transcrição GênicaRESUMO
Triple-negative breast cancer (TNBC) has a poor clinical outcome, due to a lack of actionable therapeutic targets. Herein we define lysosomal acid lipase A (LIPA) as a viable molecular target in TNBC and identify a stereospecific small molecule (ERX-41) that binds LIPA. ERX-41 induces endoplasmic reticulum (ER) stress resulting in cell death, and this effect is on target as evidenced by specific LIPA mutations providing resistance. Importantly, we demonstrate that ERX-41 activity is independent of LIPA lipase function but dependent on its ER localization. Mechanistically, ERX-41 binding of LIPA decreases expression of multiple ER-resident proteins involved in protein folding. This targeted vulnerability has a large therapeutic window, with no adverse effects either on normal mammary epithelial cells or in mice. Our study implicates a targeted strategy for solid tumors, including breast, brain, pancreatic and ovarian, whereby small, orally bioavailable molecules targeting LIPA block protein folding, induce ER stress and result in tumor cell death.
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Estresse do Retículo Endoplasmático , Neoplasias de Mama Triplo Negativas , Animais , Humanos , Lipase/química , Camundongos , Dobramento de Proteína , Neoplasias de Mama Triplo Negativas/genéticaRESUMO
The bromodomain and extraterminal (BET) family of chromatin reader proteins bind to acetylated histones and regulate gene expression. The development of BET inhibitors (BETi) has expanded our knowledge of BET protein function beyond transcriptional regulation and has ushered several prostate cancer (PCa) clinical trials. However, BETi as a single agent is not associated with antitumor activity in patients with castration-resistant prostate cancer (CRPC). We hypothesized novel combinatorial strategies are likely to enhance the efficacy of BETi. By using PCa patient-derived explants and xenograft models, we show that BETi treatment enhanced the efficacy of radiation therapy (RT) and overcame radioresistance. Mechanistically, BETi potentiated the activity of RT by blocking DNA repair. We also report a synergistic relationship between BETi and topoisomerase I (TOP1) inhibitors (TOP1i). We show that the BETi OTX015 synergized with the new class of synthetic noncamptothecin TOP1i, LMP400 (indotecan), to block tumor growth in aggressive CRPC xenograft models. Mechanistically, BETi potentiated the antitumor activity of TOP1i by disrupting replication fork stability. Longitudinal analysis of patient tumors indicated that TOP1 transcript abundance increased as patients progressed from hormone-sensitive prostate cancer to CRPC. TOP1 was highly expressed in metastatic CRPC, and its expression correlated with the expression of BET family genes. These studies open new avenues for the rational combinatorial treatment of aggressive PCa.
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Neoplasias de Próstata Resistentes à Castração , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Histonas/metabolismo , Humanos , Masculino , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/radioterapia , Fatores de Transcrição/genéticaRESUMO
Purpose: Stereotactic ablative radiation (SAbR) has been increasingly used in prostate cancer (PCa) given its convenience and cost efficacy. Optimal doses remain poorly defined with limited prospective comparative trials and long-term safety/efficacy data at higher dose levels. We analyzed toxicity and outcomes for SAbR in men with localized PCa at escalated 45 Gy in 5 fractions. Methods and Materials: This study retrospectively analyzed men from 2015 to 2019 with PCa who received linear-accelerator-based SAbR to 45 Gy in 5 fractions, along with perirectal hydrogel spacer, fiducial placement, and MRI-based planning. Disease control outcomes were calculated from end of treatment. Minimally important difference (MID) assessing patient-reported quality of life was defined as greater than a one-half standard deviation increase in American Urological Association (AUA) symptom score after SAbR. Results: Two-hundred and forty-nine (249) low-, intermediate-, and high-risk PCa patients with median follow-up of 14.9 months for clinical toxicity were included. Acute urinary grade II toxicity occurred in 20.4% of patients. Acute grade II GI toxicity occurred in 7.3% of patients. For follow-up > 2 years (n = 69), late GU and GI grade ≥III toxicity occurred in 5.8% and 1.5% of patients, respectively. MID was evident in 31.8%, 23.4%, 35.8%, 37.0%, 33.3%, and 26.7% of patients at 3, 6, 12, 24, 36, and 48 months, respectively. The median follow-up for biochemical recurrence was 22.6 months with biochemical failure-free survival of 100% at 1 year (n = 226) and 98.7% for years 2 (n = 113) and 3 (n = 54). Conclusions: SAbR for PCa at 45 Gy in 5 fractions shows an encouraging safety profile. Prospective studies with longer follow-up are warranted to establish this dose regimen as standard of care for PCa.
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BACKGROUND: Neuroendocrine prostate cancer (NEPC) is often diagnosed as a sub-type from the castration-resistant prostate cancer (CRPC) recurred from the second generation of anti-androgen treatment and is a rapidly progressive fatal disease. The molecular mechanisms underlying the trans-differentiation from CRPC to NEPC are not fully characterized, which hampers the development of effective targeted therapy. METHODS: Bioinformatic analyses were conducted to determine the clinical correlation of sphingosine kinase 1 (SphK1) in CRPC progression. To investigate the transcriptional regulation SphK1 and neuroendocrine (NE) transcription factor genes, both chromosome immunoprecipitation and luciferase reporter gene assays were performed. To demonstrate the role of SphK1 in NEPC development, neurosphere assay was carried out along with several biomarkers determined by quantitative PCR and western blot. Furthermore, in vivo NEPC xenograft models and patient-derived xenograft (PDX) model were employed to determine the effect of SphK1 inhibitors and target validation. RESULTS: Significant prevalence of SphK1 in NEPC development is observed from clinical datasets. SphK1 is transcriptionally repressed by androgen receptor-RE1-silencing transcription factor (REST) complex. Furthermore, sphingosine 1-phosphate produced by SphK1 can modulate REST protein turnover via MAPK signaling pathway. Also, decreased REST protein levels enhance the expression of NE markers in CRPC, enabling the transition to NEPC. Finally, specific SphK1 inhibitors can effectively inhibit the growth of NEPC tumors and block the REST protein degradation in PDX. CONCLUSIONS: SphK1 plays a central role in NEPC development, which offers a new target for this lethal cancer using clinically approved SphK1 inhibitors.
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Carcinoma Neuroendócrino/etiologia , Fosfotransferases (Aceptor do Grupo Álcool)/efeitos adversos , Neoplasias da Próstata/etiologia , Carcinoma Neuroendócrino/genética , Humanos , Masculino , Terapia de Alvo Molecular/métodos , Terapia de Alvo Molecular/estatística & dados numéricos , Sistemas Neurossecretores/anormalidades , Sistemas Neurossecretores/fisiopatologia , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologiaRESUMO
The androgen receptor (AR) plays a central role in prostate cancer. Development of castration resistant prostate cancer (CRPC) requires androgen-independent activation of AR, which involves its large N-terminal domain (NTD) and entails extensive epigenetic changes depending in part on histone lysine demethylases (KDMs) that interact with AR. The AR-NTD is rich in low-complexity sequences, including a polyQ repeat. Longer polyQ sequences were reported to decrease transcriptional activity and to protect against prostate cancer, although they can lead to muscular atrophy. However, the molecular mechanisms underlying these observations are unclear. Using NMR spectroscopy, here we identify weak interactions between the AR-NTD and the KDM4A catalytic domain, and between the AR ligand-binding domain and a central KDM4A region that also contains low-complexity sequences. We also show that the AR-NTD can undergo liquid-liquid phase separation in vitro, with longer polyQ sequences phase separating more readily. Moreover, longer polyQ sequences hinder nuclear localization in the absence of hormone and increase the propensity for formation of AR-containing puncta in the nucleus of cells treated with dihydrotestosterone. These results lead us to hypothesize that polyQ-dependent liquid-liquid phase separation may provide a mechanism to decrease the transcriptional activity of AR, potentially opening new opportunities to design effective therapies against CRPC and muscular atrophy.
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Regulação Neoplásica da Expressão Gênica/genética , Peptídeos/metabolismo , Receptores Androgênicos/genética , Androgênios , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Expressão Gênica/genética , Glutamina/metabolismo , Humanos , Masculino , Peptídeos/genética , Neoplasias da Próstata/genética , Neoplasias de Próstata Resistentes à Castração/genética , Domínios Proteicos/genética , Receptores Androgênicos/metabolismo , Transdução de Sinais/genética , Ativação Transcricional/genéticaRESUMO
PURPOSE: Radiation dose intensification improves outcome in men with high-risk prostate cancer (HR-PCa). A prospective trial was conducted to determine safety, feasibility, and maximal tolerated dose of multilevel magnetic resonance imaging (MRI)-based 5-fraction SABR in patients with HR-PCa. METHODS AND MATERIALS: This phase I clinical trial enrolled patients with HR-PCa with grade group ≥4, prostate-specific antigen (PSA) ≥20 ng/mL, or radiographic ≥T3, and well-defined prostatic lesions on multiparametric MRI (mpMRI) into 4 dose-escalation cohorts. The initial cohort received 47.5 Gy to the prostate, 50 Gy to mpMRI-defined intraprostatic lesion(s), and 22.5 Gy to pelvic lymph nodes in 5 fractions. Radiation doses were escalated for pelvic nodes to 25 Gy and mpMRI lesion(s) to 52.5 Gy and then 55 Gy. Escalation was performed sequentially according to rule-based trial design with 7 to 15 patients per cohort and a 90-day observation period. All men received peri-rectal hydrogel spacer, intraprostatic fiducial placement, and 2 years of androgen deprivation. The primary endpoint was maximal tolerated dose according to a 90-day acute dose-limiting toxicity (DLT) rate <33%. DLT was defined as National Cancer Institute Common Toxicity Criteria for Adverse Events ≥grade 3 treatment-related toxicity. Secondary outcomes included acute and delayed gastrointestinal (GI)/genitourinary (GU) toxicity graded with Common Toxicity Criteria for Adverse Events. RESULTS: Fifty-five of the 62 enrolled patients were included in the analysis. Dose was escalated through all 4 cohorts without observing any DLTs. Median overall follow-up was 18 months, with a median follow-up of 42, 24, 12, and 7.5 months for cohorts 1 to 4 respectively. Acute and late grade 2 GU toxicities were 25% and 20%, while GI were 13% and 7%, respectively. Late grade 3 GU and GI toxicities were 2% and 0%, respectively. CONCLUSIONS: SABR dose for HR-PCa was safely escalated with multilevel dose painting of 47.5 Gy to prostate, 55 Gy to mpMRI-defined intraprostatic lesions, and 25 Gy to pelvic nodal region in 5 fractions. Longer and ongoing follow-up will be required to assess late toxicity.
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Neoplasias da Próstata , Radioterapia de Intensidade Modulada , Antagonistas de Androgênios , Fracionamento da Dose de Radiação , Humanos , Imageamento por Ressonância Magnética , Masculino , Estudos Prospectivos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Neoplasias da Próstata/radioterapiaRESUMO
Neuroendocrine prostate cancer (NEPC) is an aggressive and lethal variant of prostate cancer (PCa), and it remains a diagnostic challenge. Herein we report our findings of using synaptic vesicle glycoprotein 2 isoform A (SV2A) as a promising marker for positron emission tomography (PET) imaging of neuroendocrine differentiation (NED). The bioinformatic analyses revealed an amplified SV2A gene expression in clinical samples of NEPC versus castration-resistant PCa with adenocarcinoma characteristics (CRPC-Adeno). Importantly, significantly upregulated SV2A protein levels were found in both NEPC cell lines and tumor tissues. PET imaging studies were carried out in NEPC xenograft models with 18F-SynVesT-1. Although 18F-SynVesT-1 is not a cancer imaging agent, it showed a significant uptake level in the SV2A+ tumor (NCI-H660: 0.70 ± 0.14 %ID/g at 50-60 min p.i.). The SV2A blockade resulted in a significant reduction of tumor uptake (0.25 ± 0.03 %ID/g, p = 0.025), indicating the desired SV2A imaging specificity. Moreover, the comparative PET imaging study showed that the DU145 tumors could be clearly visualized by 18F-SynVesT-1 but not 68Ga-PSMA-11 nor 68Ga-DOTATATE, further validating the role of SV2A-targeted imaging for noninvasive assessment of NED in PCa. In conclusion, we demonstrated that SV2A, highly expressed in NEPC, can serve as a promising target for noninvasive imaging evaluation of NED.
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Carcinoma Neuroendócrino/diagnóstico por imagem , Glicoproteínas de Membrana/análise , Proteínas do Tecido Nervoso/análise , Tomografia por Emissão de Pósitrons/métodos , Neoplasias da Próstata/diagnóstico por imagem , Animais , Carcinoma Neuroendócrino/metabolismo , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos , Compostos Organometálicos , Neoplasias da Próstata/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Histone deacetylase inhibitors (HDACi) are identified as novel therapeutic agents, however, recent clinical studies suggested that they are marginally effective in treating triple negative breast cancer (TNBC). Here, we show that first-in-class Leukemia Inhibitory Factor Receptor (LIFRα) inhibitor EC359 could enhance the therapeutic efficacy of HDACi against TNBC. We observed that both targeted knockdown of LIFR with CRISPR or treatment with EC359 enhanced the potency of four different HDACi in reducing cell viability, cell survival, and enhanced apoptosis compared to monotherapy in TNBC cells. RNA-seq studies demonstrated oncogenic/survival signaling pathways activated by HDACi were attenuated by the EC359 + HDACi therapy. Importantly, combination therapy potently inhibited the growth of TNBC patient derived explants, cell derived xenografts and patient-derived xenografts in vivo. Collectively, our results suggest that targeted inhibition of LIFR can enhance the therapeutic efficacy of HDACi in TNBC.