N-Myc Induces an EZH2-Mediated Transcriptional Program Driving Neuroendocrine Prostate Cancer

In Vivo Efficacy of a Macrocyclic Peptoid-Peptide Hybrid That Selectively Modulates the Beta-Catenin/TCF Interaction to Inhibit Prostate Cancer

BACKGROUND

Prostate cancer is the most common form of male cancer and can initially be treated as a localized disease. Although the 5-year survival rate at diagnosis approaches 100 percent, a subset of patients will subsequently develop resistance to treatment. This may ultimately lead to metastatic castration resistant prostate cancer (mCRPC), for which the prognosis is much less favorable. The importance of the Wnt/β-catenin pathway in treatment-resistant prostate cancer has inspired efforts to exploit the interaction of β-catenin with its transcription binding partners as a therapeutic strategy for prostate cancer.

METHODS

Peptoid-peptide macrocycles are attractive design scaffolds for disrupting protein-protein interactions. In this study, we evaluate a library of these macrocycles and demonstrate their selectivity for the β-catenin/TCF (T Cell Factor) interaction.

RESULTS

Importantly, we show that the macrocycles do not significantly alter the binding of β-catenin to cell surface protein, E-cadherin. Our lead sequence, Macrocycle 13, (MC13) was also tolerant of modifications aimed to improve aqueous solubility while retaining activity. Herein, we demonstrate in vivo proof of principle for using peptidomimetic macrocycles to target the β-catenin/TCF interaction. Treated prostate cancer mouse xenografts show markedly diminished tumor growth and decreased levels of myc protein. MC13 also inhibits growth in an organoid model with genetic alterations frequently found in prostate cancer. Transcriptome analysis of prostate cancer cells treated with MC13 reveals downregulation of key pathways, including Wnt/β-catenin and c-myc. Furthermore, chromatin immunoprecipitation (ChIP) analysis shows reduced β-catenin at its target genes, axin2 and c-myc.

CONCLUSION

Our findings underscore the therapeutic potential of peptoid-peptide macrocycle inhibition of β-catenin in prostate cancer.

Inhibition of Mitochondrial-Associated Protein MAGMAS Resensitizes Chemoresistant Prostate Cancer Cells to Docetaxel

BACKGROUND/OBJECTIVES

Metastatic prostate cancer (PCa) is the leading cause of cancer-related deaths and a major contributor to cancer mortality in men. Most patients with metastatic PCa eventually develop metastatic castration-resistant prostate cancer (mCRPC), characterized by resistance to treatment with androgen-deprivation therapy, and often later the development of resistance to other types of agents. MAGMAS, a 13.8 kDa mitochondrial-associated protein, facilitates the import of nuclear-encoded proteins into the mitochondrial matrix. Overexpression of MAGMAS has been observed in several aggressive cancers, including breast, glioblastoma, and prostate cancer. When overexpressed, MAGMAS acts as a cytoprotective protein by scavenging reactive oxygen species (ROS), maintaining ROS levels that support cell proliferation while avoiding the induction of apoptosis. This study investigates the role of MAGMAS in therapy resistance in PCa cells.

METHODS/RESULTS

Quantitative immunoblotting revealed that MAGMAS is endogenously upregulated in docetaxel-resistant (DR) PCa cell lines compared to their docetaxel-sensitive parental counterparts. While MAGMAS depletion alone did not affect the survival of DR cells, it significantly sensitized them to docetaxel (DTX), as indicated by a marked reduction in clonogenic potential. Additionally, transient knockdown of MAGMAS in these resistant cells significantly decreased the levels of ABCB1 protein. Consistent with these findings, sub-therapeutic inhibition of MAGMAS using the novel BT#9 inhibitor, in combination with increasing concentrations of DTX, enhanced the sensitivity of DR cells to DTX, as demonstrated by proliferation and clonogenic assays. Lastly, RNA tumor expression predicts overall survival (OS).

CONCLUSIONS

These results implicate MAGMAS in PCa chemoresistance and suggest that targeting this protein could provide a novel therapeutic strategy for treating DR tumors.

A novel role for Neurog2 in MYCN driven neuroendocrine plasticity of prostate cancer

Neuroendocrine prostate cancer (NEPC) presents a formidable clinical challenge owing to its aggressive progression and resistance to conventional therapies. A key driver of NEPC is the overexpression of MYCN, a well-established oncogene associated with neuroendocrine tumors. However, efforts to directly inhibit the N-Myc protein encoded by this gene have resulted in limited success, thereby hindering therapeutic advancements. To overcome this obstacle, we conducted unbiased genome-wide screening using isogenic prostate cancer cell lines to identify the synthetic vulnerabilities of MYCN. Among the identified candidates, NEUROG2 emerged as a significant candidate. Neurog2 is a proneural transcription factor (PTF) known for its role in developmental processes and trans-differentiation of adult cells. Our findings demonstrate that Neurog2 depletion does not affect non-malignant cells but significantly suppresses the growth of MYCN-overexpressing cells and tumors in orthotopic NEPC models. Furthermore, our observations indicate that Neurog2-driven modulation of PTFs potentially contribute to NEPC development. Thus, targeting Neurog2 holds promise as an effective therapeutic strategy for MYCN-overexpressing NEPC.

Myc family proteins: Molecular drivers of tumorigenesis and resistance in neuroendocrine tumors

Neuroendocrine cancers are a diverse and poorly understood collection of malignancies derived from neuroendocrine cells throughout the body. These cancers uniquely exhibit properties of both the nervous and endocrine systems. Only a limited number of genetic driver mutations have been identified in neuroendocrine cancers, however the mechanisms of how these genetic aberrations alter tumor biology remain elusive. Recent studies have implicated the MYC family of transcription factors as important oncogenic factors in neuroendocrine tumors. We take a systematic approach to understand the roles of the MYC family (c-MYC, n-MYC, l-MYC) in the tumorigenesis of neuroendocrine cancers of the lung, GI tract, pancreas, kidney, prostate, pediatric neuroblastoma, and adrenal glands. Reflecting the complexity of neuroendocrine cancers, we highlight the roles of the MYC family in deregulating the cell cycle and transcriptional networks, invoking cellular plasticity, affecting proliferation capacity, aiding in chromatin remodeling, angiogenesis, metabolic changes, and resistance mechanisms. Depicting the diversity of neuroendocrine cancers, we suggest new approaches in understanding the underlying tumorigenic processes of neuroendocrine cancers from the perspective of MYC.

The mechanism of histone modifications in regulating enzalutamide sensitivity in advanced prostate cancer

Prostate cancer (PCa) is the second most common malignant tumor in men worldwide, particularly castration-resistant prostate cancer (CRPC), for which enzalutamide (Enz) resistance is of particular concern. Modifications to histone methylation and acetylation patterns are closely associated with resistance to Enz in these patients. As PCa progresses, cancer cells alter their histone modification patterns, leading to a reduction in Enz treatment efficacy. Signaling pathways in the tumor microenvironment regulate gene expression by affecting the activity of histone-modifying enzymes, further affecting the efficacy of Enz. This review summarizes recent research about changes in histone modification patterns that occur in drug resistance-related genes at different stages of PCa and explores the potential use of combination therapies for reversing this process, providing insights into novel treatment strategies to improve the clinical efficacy of Enz.

Targeting the histone reader ZMYND8 inhibits antiandrogen-induced neuroendocrine tumor transdifferentiation of prostate cancer

The transdifferentiation from adenocarcinoma to neuroendocrine prostate cancer (NEPC) in men confers antiandrogen therapy resistance. Here our analysis combining CRISPR‒Cas9 screening with single-cell RNA sequencing tracking of tumor transition demonstrated that antiandrogen-induced zinc finger MYND-type containing 8 (ZMYND8)-dependent epigenetic programming orchestrates NEPC transdifferentiation. Ablation of Zmynd8 prevents NEPC development, while ZMYND8 upregulation mediated by achaete-scute homolog 1 promotes NEPC differentiation. We show that forkhead box protein M1 (FOXM1) stabilizes ZMYND8 binding to chromatin regions characterized by H3K4me1-H3K14ac modification and FOXM1 targeting. Antiandrogen therapy releases the SWI/SNF chromatin remodeling complex from the androgen receptor, facilitating its interaction with ZMYND8-FOXM1 to upregulate critical neuroendocrine lineage regulators. We develop iZMYND8-34, a small molecule designed to inhibit ZMYND8's histone recognition, which effectively blocks NEPC development. These findings reveal the critical role of ZMYND8-dependent epigenetic programming induced by androgen deprivation therapy in orchestrating lineage fate. Targeting ZMYND8 emerges as a promising strategy for impeding NEPC development.

Predicting Survival in Patients with Neuroendocrine Prostate Cancer: A SEER-Based Comprehensive Study

PURPOSE

Neuroendocrine prostate cancer (NEPC) represents a particularly aggressive subtype of prostate cancer with a challenging prognosis. The purpose of this investigation is to craft and confirm the reliability of nomograms that can accurately forecast the 1-, 3-, and 5-year overall survival (OS) and cancer-specific survival (CSS) rates for individuals afflicted with NEPC.

MATERIALS AND METHODS

Data pertaining to patients diagnosed with NEPC within the timeframe of 2010 to 2020 was meticulously gathered and examined from the Surveillance, Epidemiology, and End Results Program (SEER). To predict OS and CSS, we devised and authenticated two distinct nomograms, utilizing predictive variables pinpointed through both univariate and multivariate Cox regression analyses.

RESULTS

The study encompassed 393 of NEPC patients, who were systematically divided into training and validation cohorts at a 2:1 ratio. Key prognostic factors were isolated, verified, and integrated into the respective nomograms for OS and CSS. The performance metrics, denoted by C-indices, stood at 0.730, 0.735 for the training set, and 0.784, 0.756 for the validation set. The precision and clinical relevance of the nomograms were further corroborated by the analysis of receiver operating characteristic curves, calibration plots, and decision curve analyses.

CONCLUSIONS

The constructed nomograms have demonstrated impressive efficacy in forecasting the 1-, 3-, and 5-year OS and rates for patients with NEPC. Implementing these predictive tools in clinical settings is anticipated to considerably enhance the care and treatment planning for individuals diagnosed with this aggressive form of prostate cancer, thus providing tailored and more precise prognostic assessments.

Squamocin Suppresses Tumor Growth through Triggering an Endoplasmic Reticulum Stress-Associated Degradation of EZH2/MYC Axis

Despite substantial advances in the antitumor effects of annonaceous acetogenins (ACGs), the absence of a defined biological action mechanism remains a major barrier to their clinical application. Here, it is found that squamocin effectively depletes both EZH2 and MYC in multiple cancer cell lines, including head and neck squamous cell carcinoma, and gastric and colorectal cancer, demonstrating potent efficacy in suppressing these in vivo tumor models. Through the combination of surface plasmon resonance (SPR), differential scanning fluorimetry (DSF), and cellular thermal shift assay (CETSA), heat shock protein 90α (HSP90α) is identified as the direct binding target of squamocin. Mechanistically, squamocin disrupts mitochondrial respiratory Complex I function, reduces ATP production, and impairs HSP90α function, provoking endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). These intrinsic events within tumor cells enhance ER stress-associated ubiquitylation and degradation by triggering ubiquitin via the E1 activase UBA6, facilitating ubiquitin transferring to E2 conjugate UBE2Z and increasing the activities of E3 ligase FBXW7 to degrade both EZH2 and MYC. The findings elucidate the role of squamocin in the degradation of oncoproteins EZH2 and MYC by triggering an ER stress-associated UBA6-UBE2Z-FBXW7 ubiquitin cascade, providing insights that may accelerate therapeutic development targeting tumors driven by the EZH2/MYC axis.

The role of transcription factors in prostate cancer progression

Prostate cancer is one of the most common malignancies in men, with most cases initially responding to androgen deprivation therapy. However, a significant number of patients eventually develop castration-resistant prostate cancer, an aggressive form of the disease. Although androgen receptor (AR) pathway inhibitors target AR signaling, and have extended survival in patients with castration-resistant prostate cancer, prolonged treatment can lead to the emergence of neuroendocrine prostate cancer (NEPC), a lethal subtype characterized by the expression of neuroendocrine markers and reduced AR activity. The transition from adenocarcinoma to NEPC is driven by lineage plasticity, wherein cancer cells adopt a neuroendocrine phenotype to evade treatment. Consequently, NEPC patients face poor clinical outcomes and limited effective treatment options. To improve outcomes, it is crucial to understand the molecular mechanisms driving NEPC development. In this review, we highlight the role of transcription factors in this process and explore their potential as therapeutic targets.

ETV5 reduces androgen receptor expression and induces neural stem-like properties during neuroendocrine prostate cancer development

Neuroendocrine prostate cancer (NEPC), an aggressive subtype induced by hormone therapy, lacks effective treatments. This study explored the role of E26 transformation-specific variant 5 (ETV5) in NEPC development. Analysis of multiple prostate cancer datasets revealed that NEPC is characterized by significantly elevated ETV5 expression compared to other subtypes. ETV5 expression increased progressively under hormone therapy through epigenetic modifications. ETV5 induced neural stem-like features in prostate cancer cells and facilitated their differentiation into NEPC under hormone treatment conditions, both in vitro and in vivo. Our molecular mechanistic study identified PBX3 and TLL1 as target genes of ETV5 that contribute to ETV5 overexpression-induced castration resistance and stemness. Notably, obeticholic acid, identified as an ETV5 inhibitor in this study, exhibited promising efficacy in suppressing NEPC development. This study highlights ETV5 as a key transcription factor that facilitates NEPC development and underscores its potential as a therapeutic target for this aggressive cancer subtype.

Defined cellular reprogramming of androgen receptor-active prostate cancer to neuroendocrine prostate cancer

Neuroendocrine prostate cancer (NEPC) arises primarily through neuroendocrine transdifferentiation (NEtD) as an adaptive mechanism of therapeutic resistance. Models to define the functional effects of putative drivers of this process on androgen receptor (AR) signaling and NE cancer lineage programs are lacking. We adapted a genetically defined strategy from the field of cellular reprogramming to directly convert AR-active prostate cancer (ARPC) to AR-independent NEPC using candidate factors. We delineated critical roles of the pioneer factors ASCL1 and NeuroD1 in NEtD and uncovered their abilities to silence AR expression and signaling by remodeling chromatin at the somatically acquired AR enhancer and global AR binding sites with enhancer activity. We also elucidated the dynamic temporal changes in the transcriptomic and epigenomic landscapes of cells undergoing acute lineage conversion from ARPC to NEPC which should inform future therapeutic development. Further, we distinguished the activities of ASCL1 and NeuroD1 from the inactivation of RE-1 silencing transcription factor (REST), a master suppressor of a major neuronal gene program, in establishing a NEPC lineage state and in modulating the expression of genes associated with major histocompatibility complex class I (MHC I) antigen processing and presentation. These findings provide important, clinically relevant insights into the biological processes driving NEtD of prostate cancer.

Effective therapeutic targeting of tumor lineage plasticity in neuroendocrine prostate cancer by BRD4 inhibitors

Tumor lineage plasticity (LP) is an emerging hallmark of cancer progression. Through pharmacologically probing the function of epigenetic regulators in prostate cancer cells and organoids, we identified bromodomain protein BRD4 as a crucial player. Integrated ChIP-seq and RNA-seq analysis of tumors revealed, for the first time, that BRD4 directly activates hundreds of genes in the LP programs which include neurogenesis, axonogenesis, EMT and stem cells and key drivers such as POU3F2 (BRN2), ASCL1/2, NeuroD1, SOX2/9, RUNX1/2 and DLL3. Interestingly, BRD4 genome occupancy is reprogrammed by anti-AR drugs from facilitating AR function in CRPC cells to activating the LP programs and is facilitated by pioneer factor FOXA1. Significantly, we demonstrated that BRD4 inhibitor AZD5153, currently at clinical development, possesses potent activities in complete blockade of tumor growth of both de novo neuroendocrine prostate cancer (NEPC) and treatment-induced NEPC PDXs and that suppression of tumor expression of LP programs through reduction of local chromatin accessibility is the primary mechanism of action (MOA) by AZD5153. Together, our study revealed that BRD4 plays a fundamental role in direct activation of tumor LP programs and that its inhibitor AZD5153 is highly promising in effective treatment of the lethal forms of the diseases.

Targeting the MYCN-MDM2 pathways for cancer therapy: Are they druggable?

Targeting oncogenes and their interactive partners is an effective approach to developing novel targeted therapies for cancer and other chronic diseases. We and others have long suggested the MDM2 oncogene being an excellent target for cancer therapy, based on its p53-dependent and -independent oncogenic activities in a variety of cancers. The MYC family proteins are transcription factors that also regulate diverse biological functions. Dysregulation of MYC, such as amplification of MYCN, is associated with tumorigenesis, especially for neuroblastoma. Although the general survival rate of neuroblastoma patients has significantly improved over the past few decades, high-risk neuroblastoma still presents a poor prognosis. Therefore, innovative and more potent therapeutic strategies are needed to eradicate these aggressive neoplasms. This review focuses on the oncogenic properties of MYCN and its molecular regulation and summarizes the major therapeutic strategies being developed based on preclinical findings. We also highlight the potential benefits of targeting both the MYCN and MDM2 oncogenes, providing preclinical evidence of the efficacy and safety of this approach. In conclusion, the development of effective small molecules that inhibit both MYCN and MDM2 represents a promising new strategy for the treatment of neuroblastoma and other cancers.

The emerging landscape and future perspective of SCLC transformation: From molecular mechanisms to therapeutic strategies

Small-cell lung cancer (SCLC) is featured by high malignancy and undesirable prognosis. Transformed SCLC shares several common grounds but differ in biological behavior, molecular mechanism and therapeutic options from typical SCLC. SCLC transformation exerts indispensable role in drug resistance among patients with non-small cell lung cancer (NSCLC) upon various treatment modalities. Two hypotheses have been raised to account for SCLC transformation. It develops mostly in EGFR-mutant adenocarcinoma, and can also occur in ALK or ROS1 mutant patients, and EGFR-wildtype adenocarcinoma. Effective biomarkers for early detection, and therapeutic strategies are vital for improving survival for patients undergoing SCLC transformation. This review summarizes the emerging landscape in transformed SCLC, including its origin, molecular mechanisms, approaches for early detection and corresponding therapeutic options, in a bid to gain a comprehensive insight of this recalcitrant and tricky disease. More importantly, we also discuss challenges that lie ahead and future perspectives on this aggressive malignancy.

A highly sensitive screening system to evaluate the reversibility of neuroendocrine prostate cancer to prostate adenocarcinoma

We established a robust and sensitive androgen response element luciferase reporter assay to monitor androgen receptor (AR) activity using KUCaP13 cells, a novel human-derived treatment-related neuroendocrine prostate cancer (t-NEPC) cell line. A high-throughput screening using a chemical library to identify potential compounds that induce AR re-expression in KUCaP13 cells revealed 30 candidate molecules potentially enhancing luciferase luminescence; however, subsequent validation steps demonstrated these signals to be false-positives. Despite not achieving the goal of AR re-expression, this study stands as a significant proof-of-concept for the application of high-throughput screening approaches in t-NEPC research.

Deciphering Complexity: The Molecular Landscape of Castration-Resistant Prostate Cancer

Despite improvements in diagnosis and treatment approaches, prostate cancer (PC) remains a leading cause of cancer-related death in men. PC progresses through various stages, mostly driven by androgen receptor signaling. However, after androgen deprivation therapies, in a significant portion of patients, several different molecular mechanisms contribute to the development of castration resistance. Delving deeply into the molecular landscape of castration-resistant PC, grasping the selective pressures exerted by therapies, and understanding the drivers of lineage plasticity is pivotal to prevent progression. Targeting genetic and epigenetic alterations that drive this transition will guide clinical management strategies and possibly prevent and/or treat lethal disease.

Aurora A Kinase Inhibition Is Synthetic Lethal With the Activation of MYCN in Retinoblastoma

Purpose

RB1 inactivation and MYCN activation have been documented as common oncogenic alterations in retinoblastoma (RB). Direct targeting of RB1 and MYCN has not yet been proven to be feasible. The current treatment options for RB mainly consist of conventional chemotherapy, which inevitably poses health-threatening side effects. Here, we aimed to screen an in-house compound library to identify potential drugs for the treatment of human RB.

Methods

Aurora A kinase (AURKA) inhibitors were identified by differential viability screening with a tool compound library, and the pharmacological safety and efficacy of candidate drugs were further validated in zebrafish and RB patient-derived xenograft (PDX) models in vivo. Further CUT & Tag assay, ChIP-qPCR and RNA seq performances showed that MYCN binds to the AURKA promoter and upregulates its transcription, suggesting that AURKA inhibition induces synthetic lethality in RB.

Results

In this study, we revealed that AURKA inhibitors exhibited high therapeutic efficacy against RB both in vitro and in vivo. Mechanistically, we found that MYCN could bind to the AURKA promoter region to regulate its transcription, thereby promoting AURKA expression and consequently driving RB progression. Interestingly, AURKA inhibition exhibited synthetic lethality with RB1-deficient and MYCN-amplification in RB cells.

Conclusions

Collectively, these findings demonstrate that AURKA is crucial for RB progression and further expanded the current understanding of synthetic lethal therapeutic strategies. Our study indicates that AURKA inhibitors may represent a new therapeutic strategy for selectively targeting patients with RB with RB1-deficient and MYCN-amplification to improve the prognosis of aggressive types of patients with RB.

A systematic review on the culture methods and applications of 3D tumoroids for cancer research and personalized medicine

Cancer is a highly heterogeneous disease, and thus treatment responses vary greatly between patients. To improve therapy efficacy and outcome for cancer patients, more representative and patient-specific preclinical models are needed. Organoids and tumoroids are 3D cell culture models that typically retain the genetic and epigenetic characteristics, as well as the morphology, of their tissue of origin. Thus, they can be used to understand the underlying mechanisms of cancer initiation, progression, and metastasis in a more physiological setting. Additionally, co-culture methods of tumoroids and cancer-associated cells can help to understand the interplay between a tumor and its tumor microenvironment. In recent years, tumoroids have already helped to refine treatments and to identify new targets for cancer therapy. Advanced culturing systems such as chip-based fluidic devices and bioprinting methods in combination with tumoroids have been used for high-throughput applications for personalized medicine. Even though organoid and tumoroid models are complex in vitro systems, validation of results in vivo is still the common practice. Here, we describe how both animal- and human-derived tumoroids have helped to identify novel vulnerabilities for cancer treatment in recent years, and how they are currently used for precision medicine.

EZH2 inhibition enhances the activity of Carboplatin in aggressive-variant prostate cancer cell lines

BACKGROUND

Aggressive Variant Prostate Cancers (AVPCs) are incurable malignancies. Platinum-based chemotherapies are used for the palliative treatment of AVPC. The Polycomb Repressive Complex 2 (PRC2) promotes prostate cancer progression via histone H3 Lysine 27 tri-methylation (H3K27me3). EZH2 encodes the catalytic subunit of PRC2. A recently developed nucleosome capture technology (Nu.QⓇ).measures H3K27me3 levels in biological fluids. EZH2 inhibitors (EZH2i) are being tested in clinical trials. We hypothesize that epigenetic reprogramming via EZH2i improves the efficacy of Carboplatin in AVPC and that EZH2i activity can be measured via both cellular- and cell-free nucleosomal H3K27me3 (cf-H3K27me3) levels.

METHODS

We studied the expression of PRC2 genes in clinical prostate cancer cohorts (bioinformatics). We determined the effect of EZH2i on cellular- and cf-H3K27me3 levels. We measured dose-dependent effects of Carboplatin with/without EZH2i on AVPC cell viability (IC50). We used RNA-Seq to study how EZH2i modulates gene expression in AVPC cells.

RESULTS

PRC2 genes were significantly up-regulated in AVPC vs other prostate cancer types. EZH2i reduced both cellular and cf-H3K27me3 levels. EZH2i significantly reduced Carboplatin IC50. EZH2i reduced the expression of DNA repair genes and increased the expression of p53-dependent pro-apoptotic factors.

CONCLUSIONS

EZH2i plus Carboplatin is a promising combination treatment for AVPC.

Interactions between key genes and pathways in prostate cancer progression and therapy resistance

Prostate cancer is one of the most prevalent malignant tumors in men, particularly in regions with a high Human Development Index. While the long-term survival rate for localized prostate cancer is relatively high, the mortality rate remains significantly elevated once the disease progresses to advanced stages, even with various intensive treatment modalities. The primary obstacle to curing advanced prostate cancer is the absence of comprehensive treatment strategies that effectively target the highly heterogeneous tumors at both genetic and molecular levels. Prostate cancer development is a complex, multigenic, and multistep process that involves numerous gene mutations, alteration in gene expression, and changes in signaling pathways. Key genetic and pathway alterations include the amplification and/or mutation of the androgen receptor, the loss of Rb, PTEN, and p53, the activation of the WNT signaling pathway, and the amplification of the MYC oncogene. This review summarizes the mechanisms by which these genes influence the progression of prostate cancer and highlights the interactions between multiple genes and their relationship with prostate cancer. Additionally, we reviewed the current state of treatments targeting these genes and signaling pathways, providing a comprehensive overview of therapeutic approaches in the context of prostate cancer.

DLGAP5 enhances bladder cancer chemoresistance by regulating glycolysis through MYC stabilization

Rationale: Bladder cancer (BLCA), one of the most lethal urological tumors, exhibits high rates of recurrence and chemoresistance, particularly to gemcitabine (GEM). Understanding the mechanisms of GEM resistance is crucial for improving therapeutic outcomes. Our study investigates the role of DLGAP5 in promoting GEM resistance through modulation of glycolysis and MYC protein stability in BLCA cells. Methods: We utilized various BLCA cell lines and clinical tissue samples to analyze the impact of DLGAP5 on GEM resistance. Through biochemical assays, protein interaction studies, and gene expression analyses, we examined how DLGAP5 interacts with USP11 and MYC, assessed the effects on MYC deubiquitination and stability. The influence of these interactions on glycolytic activity and GEM resistance was also evaluated via mouse subcutaneous xenograft model and spontaneous BLCA model. Results: Our findings indicate that DLGAP5 enhances GEM resistance by stabilizing MYC protein via deubiquitination, a process mediated by USP11. DLGAP5 was found to facilitate the interaction between USP11 and MYC, promoting MYC-driven transcription of DLGAP5 itself, thereby creating a positive feedback loop. This loop leads to sustained MYC accumulation and increased glycolytic activity, contributing to GEM resistance in BLCA cells. Conclusion: The study highlights the critical role of DLGAP5 in regulating MYC protein stability and suggests that disrupting the DLGAP5-USP11-MYC axis may provide a novel therapeutic approach to overcome GEM resistance in BLCA. DLGAP5 represents a potential target for therapeutic intervention aimed at mitigating chemoresistance in bladder cancer BLCA.

Prostate cancer epigenetics - from pathophysiology to clinical application

Prostate cancer is a multifactorial disease influenced by various molecular features. Over the past decades, epigenetics, which is the study of changes in gene expression without altering the DNA sequence, has been recognized as a major driver of this disease. In the past 50 years, advancements in technological tools to characterize the epigenome have highlighted crucial roles of epigenetic mechanisms throughout the entire spectrum of prostate cancer, from initiation to progression, including localized disease, metastatic dissemination, castration resistance and neuroendocrine transdifferentiation. Substantial advances in the understanding of epigenetic mechanisms in the pathophysiology of prostate cancer have been carried out, but translating preclinical achievements into clinical practice remains challenging. Ongoing research and biomarker-oriented clinical trials are expected to increase the likelihood of successfully integrating epigenetics into prostate cancer clinical management.

Emerging Role of the DREAM Complex in Cancer and Therapeutic Opportunities

The DREAM (dimerization partner, RB-like, E2F, and multi-vulval class B) complex is an evolutionarily conserved transcriptional repression complex that coordinates nearly one thousand target genes, primarily associated with the cell cycle processes. The formation of the DREAM complex consequently inhibits cell cycle progression and induces cellular quiescence. Given its unique role in cell cycle control, the DREAM complex has gained significant interest across various physiological and pathological contexts, particularly in conditions marked by dysregulated cell cycles, such as cancer. However, the specific cancer types most significantly affected by alterations in the DREAM complex are yet to be determined. Moreover, the possibility of restoring or pharmacologically targeting the DREAM complex as a therapeutic intervention against cancer remains a relatively unexplored area of research and is currently under active investigation. In this review, we provide an overview of the latest advances in understanding the DREAM complex, focusing on its role in cancer. We also explore strategies for targeting the DREAM complex as a potential approach for cancer therapeutics. Advances in understanding the precise role of the DREAM complex in cancer, combined with ongoing efforts to develop targeted therapies, may pave the way for new options in cancer therapy.

Biological determinants of PSMA expression, regulation and heterogeneity in prostate cancer

Prostate-specific membrane antigen (PSMA) is an important cell-surface imaging biomarker and therapeutic target in prostate cancer. The PSMA-targeted theranostic 177Lu-PSMA-617 was approved in 2022 for men with PSMA-PET-positive metastatic castration-resistant prostate cancer. However, not all patients respond to PSMA-radioligand therapy, in part owing to the heterogeneity of PSMA expression in the tumour. The PSMA regulatory network is composed of a PSMA transcription complex, an upstream enhancer that loops to the FOLH1 (PSMA) gene promoter, intergenic enhancers and differentially methylated regions. Our understanding of the PSMA regulatory network and the mechanisms underlying PSMA suppression is evolving. Clinically, molecular imaging provides a unique window into PSMA dynamics that occur on therapy and with disease progression, although challenges arise owing to the limited resolution of PET. PSMA regulation and heterogeneity - including intertumoural and inter-patient heterogeneity, temporal changes, lineage dynamics and the tumour microenvironment - affect PSMA theranostics. PSMA response and resistance to radioligand therapy are mediated by a number of potential mechanisms, and complementary biomarkers beyond PSMA are under development. Understanding the biological determinants of cell surface target regulation and heterogeneity can inform precision medicine approaches to PSMA theranostics as well as other emerging therapies.

Protein kinase D2-Aurora kinase A-ERK1/2 signalling axis drives neuroendocrine differentiation of epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is deadliest gynecological malignancy with poor prognosis and patient survival. Despite development of several therapeutic interventions such as poly-ADP ribose polymerase (PARP) inhibitors, EOC remains unmanageable and discovery of novel early detection biomarkers and treatment targets are highly warranted. Although neuroendocrine differentiation (NED) is implicated in different human cancers including prostate adenocarcinoma and lung cancer, mechanistic studies concerning NED of epithelial ovarian cancer are lacking. We report that Aurora kinase A drives NED of epithelial ovarian cancer in an ERK1/2-dependent manner and pharmacological and genetic inhibition of Aurora kinase A suppress NED of ovarian cancer. Moreover, we demonstrate that protein kinase D2 positively regulated Aurora kinase A to drive NED. Overexpression of catalytically active PKD2 drives NED and collectively, PKD2 cross talks with Aurora kinase A/ERK1/2 signalling axis to positively regulate NED of EOC. PKD2/Aurora kinase A/ERK1/2 signalling axis is a novel therapeutic target against neuroendocrine differentiated EOC.

Epigenetic remodeling and 3D chromatin reorganization governed by NKX2-1 drive neuroendocrine prostate cancer

A significant number of castration-resistant prostate cancer (CRPC) evolve into a neuroendocrine (NE) subtype termed NEPC, leading to resistance to androgen receptor (AR) pathway inhibitors and poor clinical outcomes. Through Hi-C analyses of a panel of patient-derived xenograft tumors, here we report drastically different 3D chromatin architectures between NEPC and CRPC samples. Such chromatin re-organization was faithfully recapitulated in vitro on isogenic cells undergoing NE transformation (NET). Mechanistically, neural transcription factor (TF) NKX2-1 is selectively and highly expressed in NEPC tumors and is indispensable for NET across various models. NKX2-1 preferentially binds to gene promoters, but it interacts with chromatin-pioneering factors such as FOXA2 at enhancer elements through chromatin looping, further strengthening FOXA2 binding at NE enhancers. Conversely, FOXA2 mediates regional DNA demethylation, attributing to NE enhancer priming and inducing NKX2-1 expression, forming a feed-forward loop. Single-cell multiome analyses of isogenic cells over time-course NET cells identify individual cells amid luminal-to-NE transformation, exhibiting intermediate epigenetic and transcriptome states. Lastly, NKX2-1/FOXA2 interacts with, and recruits CBP/p300 proteins to activate NE enhancers, and pharmacological inhibitors of CBP/p300 effectively blunted NE gene expression and abolished NEPC tumor growth. Thus, our study reports a hierarchical network of TFs governed by NKX2-1 in regulating the 2D and 3D chromatin re-organization during NET and uncovers a promising therapeutic approach to eradicate NEPC.

Therapeutic Exploitation of Neuroendocrine Transdifferentiation Drivers in Prostate Cancer

Neuroendocrine prostate cancer (NEPC), an aggressive and lethal subtype of prostate cancer (PCa), often arises as a resistance mechanism in patients undergoing hormone therapy for prostate adenocarcinoma. NEPC is associated with a significantly poor prognosis and shorter overall survival compared to conventional prostate adenocarcinoma due to its aggressive nature and limited response to standard of care therapies. This transdifferentiation, or lineage reprogramming, to NEPC is characterised by the loss of androgen receptor (AR) and prostate-specific antigen (PSA) expression, and the upregulation of neuroendocrine (NE) biomarkers such as neuron-specific enolase (NSE), chromogranin-A (CHGA), synaptophysin (SYP), and neural cell adhesion molecule 1 (NCAM1/CD56), which are critical for NEPC diagnosis. The loss of AR expression culminates in resistance to standard of care PCa therapies, such as androgen-deprivation therapy (ADT) which target the AR signalling axis. This review explores the drivers of NE transdifferentiation. Key genetic alterations, including those in the tumour suppressor genes RB1, TP53, and PTEN, and changes in epigenetic regulators, particularly involving EZH2 and cell-fate-determining transcription factors (TFs) such as SOX2, play significant roles in promoting NE transdifferentiation and facilitate the lineage switch from prostate adenocarcinoma to NEPC. The recent identification of several other key novel drivers of NE transdifferentiation, including MYCN, ASCL1, BRN2, ONECUT2, and FOXA2, further elucidates the complex regulatory networks and pathways involved in this process. We suggest that, given the multifactorial nature of NEPC, novel therapeutic strategies that combine multiple modalities are essential to overcome therapeutic resistance and improve patient outcomes.

Increased translation driven by non-canonical EZH2 creates a synthetic vulnerability in enzalutamide-resistant prostate cancer

Overcoming resistance to therapy is a major challenge in castration-resistant prostate cancer (CRPC). Lineage plasticity towards a neuroendocrine phenotype enables CRPC to adapt and survive targeted therapies. However, the molecular mechanisms of epigenetic reprogramming during this process are still poorly understood. Here we show that the protein kinase PKCλ/ι-mediated phosphorylation of enhancer of zeste homolog 2 (EZH2) regulates its proteasomal degradation and maintains EZH2 as part of the canonical polycomb repressive complex (PRC2). Loss of PKCλ/ι promotes a switch during enzalutamide treatment to a non-canonical EZH2 cistrome that triggers the transcriptional activation of the translational machinery to induce a transforming growth factor β (TGFβ) resistance program. The increased reliance on protein synthesis creates a synthetic vulnerability in PKCλ/ι-deficient CRPC.

KIF1A promotes neuroendocrine differentiation in prostate cancer by regulating the OGT-mediated O-GlcNAcylation

Neuroendocrine prostate cancer (NEPC) arises from prostate adenocarcinoma after endocrine treatment failure and implies lethality and limited therapeutic options. Deciphering the molecular mechanisms underlying transdifferentiation from adenocarcinoma to NEPC may provide valuable therapeutic strategies. We performed a pan-cancer differential mRNA abundance analysis and identified that Kinesin-like protein (KIF1A) was highly expressed in NEPC. KIF1A knockdown impaired neuroendocrine(NE) features, including NE marker gene expression, stemness, and epithelial-mesenchymal transition (EMT), whereas KIF1A overexpression promoted these processes. Targeting KIF1A inhibited the growth of NE differentiated prostate cancer (PCa) cells in vitro and in vivo. Mechanistically, KIF1A bound with O-linked N-acetylglucosamine transferase (OGT) and regulated its protein expression and activity. Nuclear accumulation of OGT induced by KIF1A overexpression promoted intranuclear O-GlcNAcylation of β-catenin and OCT4 in nucleus. More importantly, our data revealed that OGT was critical for KIF1A induced NE differentiation and aggressive tumor growth. An OGT inhibitor, OSMI-1, can significantly inhibited NE differentiated PCa cell proliferation in vitro and tumor growth in vivo. Our findings showed that KIF1A promotes NE differentiation to NEPC by regulating the OGT-mediated O-GlcNAcylation. Targeting O-GlcNAcylation may impede the development of NEPC for a group of PCa patients with elevated KIF1A expression.

IMPA1-derived inositol maintains stemness in castration-resistant prostate cancer via IMPDH2 activation

Acquisition of prostate cancer stem cells (PCSCs) manifested during androgen ablation therapy (ABT) contributes to castration-resistant prostate cancer (CRPC). However, little is known about the specific metabolites critically orchestrating this process. Here, we show that IMPA1-derived inositol enriched in PCSCs is a key metabolite crucially maintaining PCSCs for CRPC progression and ABT resistance. Notably, conditional Impa1 knockout in the prostate abrogates the pool and properties of PCSCs to orchestrate CRPC progression and prolong the survival of TRAMP mice. IMPA1-derived inositol serves as a cofactor that directly binds to and activates IMPDH2, which synthesizes guanylate nucleotides for maintaining PCSCs with ARlow/- features leading to CRPC progression and ABT resistance. IMPA1/inositol/IMPDH2 axis is upregulated in human prostate cancer, and its overexpression predicts poor survival outcomes. Genetically and pharmacologically targeting the IMPA1/inositol/IMPDH2 axis abrogates CRPC and overcomes ABT resistance in various CRPC xenografts, patient-derived xenograft (PDX) tumor models, and TRAMP mouse models. Our study identifies IMPDH2 as an inositol sensor whose activation by inositol represents a key mechanism for maintaining PCSCs for CRPC and ABT resistance.

The neuroendocrine transition in prostate cancer is dynamic and dependent on ASCL1

Lineage plasticity is a hallmark of cancer progression that impacts therapy outcomes, yet the mechanisms mediating this process remain unclear. Here, we introduce a versatile in vivo platform to interrogate neuroendocrine lineage transformation throughout prostate cancer progression. Transplanted mouse prostate organoids with human-relevant driver mutations (Rb1-/-; Trp53-/-; cMyc+ or Pten-/-; Trp53-/-; cMyc+) develop adenocarcinomas, but only those with Rb1 deletion advance to aggressive, ASCL1+ neuroendocrine prostate cancer (NEPC) resistant to androgen receptor signaling inhibitors. Notably, this transition requires an in vivo microenvironment not replicated by conventional organoid culture. Using multiplexed immunofluorescence and spatial transcriptomics, we reveal that ASCL1+ cells arise from KRT8+ luminal cells, progressing into transcriptionally heterogeneous ASCL1+;KRT8- NEPC. Ascl1 loss in established NEPC causes transient regression followed by recurrence, but its deletion before transplantation abrogates lineage plasticity, resulting in castration-sensitive adenocarcinomas. This dynamic model highlights the importance of therapy timing and offers a platform to identify additional lineage plasticity drivers.

Current uses and resistance mechanisms of enzalutamide in prostate cancer treatment

INTRODUCTION

Prostate cancer continues to be a major cause of morbidity and mortality for men worldwide. Enzalutamide, a second-generation non-steroidal antiandrogen that blocks androgen receptor (AR) transcriptional activity, is a treatment for biochemically recurrent, metastatic, castration-sensitive, and castration-resistant tumors. Unfortunately, most patients ultimately develop resistance to enzalutamide, making long-term treatment with this agent challenging.

AREAS COVERED

We performed a literature search of PubMed without date restrictions to investigate the literature surrounding enzalutamide and discuss the current uses of enzalutamide, proposed mechanisms driving resistance, and summarize current efforts to mitigate this resistance.

EXPERT OPINION

Enzalutamide is an effective prostate cancer therapy that is currently used in biochemically recurrent and metastatic disease and for both castration-sensitive and castration-resistant tumors. Unfortunately, resistance to enzalutamide occurs in each of these scenarios. In the clinical setting, enzalutamide-resistant tumors are either AR-driven or AR-indifferent. AR-dependent resistance mechanisms include genomic or epigenomic events that result in enhanced AR signaling. Tumors that do not require AR signaling instead may depend on alternative oncogenic pathways. There are numerous strategies to mitigate enzalutamide resistance, including concurrent use of PARP inhibitors or immune therapies. Additional work is required to uncover novel approaches to treat patients in the enzalutamide-resistant setting.

Acetate utilization promotes hormone therapy resistance in prostate cancer through neuroendocrine differentiation

AIMS

Tumor fatty acid (FA) metabolic plasticity plays a pivotal role in resistance to therapy and poses limitations to anticancer strategies. In this study, our aim is to uncover the role of acetate metabolism in neurodifferentiation (NED)-mediated castration-resistant prostate cancer (CRPC).

METHODS

We conducted analyses using LC-MS/MS on clinical prostate cancer tissue before and after hormone therapy. We established tumor xenograft mouse models, primary tumor cells, and human-derived organoids to detect the novel mechanism of NED and to identify potential therapies.

RESULTS

The hormone therapy-induced upregulation of acetate metabolism was mediated by acyl-CoA synthetase short-chain family member 2 (ACSS2), which increased c-MYC expression for NED induction. Notably, combined treatment with an ACSS2 inhibitor and enzalutamide significantly reduced the xenograft tumor volume.

CONCLUSION

Our findings uncovered the critical role of acetate metabolism in NED-mediated CRPC and suggest that ACSS2 inhibitors may represent a novel, low-toxicity strategy when combined with hormone therapy for treating patients with NED-mediated CRPC.

Unmasking Neuroendocrine Prostate Cancer with a Machine Learning-Driven Seven-Gene Stemness Signature That Predicts Progression

Prostate cancer (PCa) poses a significant global health challenge, particularly due to its progression into aggressive forms like neuroendocrine prostate cancer (NEPC). This study developed and validated a stemness-associated gene signature using advanced machine learning techniques, including Random Forest and Lasso regression, applied to large-scale transcriptomic datasets. The resulting seven-gene signature (KMT5C, DPP4, TYMS, CDC25B, IRF5, MEN1, and DNMT3B) was validated across independent cohorts and patient-derived xenograft (PDX) models. This signature demonstrated strong prognostic value for progression-free, disease-free, relapse-free, metastasis-free, and overall survival. Importantly, the signature not only identified specific NEPC subtypes, such as large-cell neuroendocrine carcinoma, which is associated with very poor outcomes, but also predicted a poor prognosis for PCa cases that exhibit this molecular signature, even when they were not histopathologically classified as NEPC. This dual prognostic and classifier capability makes the seven-gene signature a robust tool for personalized medicine, providing a valuable resource for predicting disease progression and guiding treatment strategies in PCa management.

Unraveling molecular characteristics and tumor microenvironment dynamics of neuroendocrine prostate cancer

Prostate cancer (PCa) is the most prevalent malignancy and the second leading cause of cancer-related deaths among men. While adenocarcinoma of the prostate (adeno-PCa) is well-characterized, neuroendocrine prostate cancer (NEPC) remains poorly understood. Generally, NEPC is a rare but highly aggressive histological variant, however its limited patho-physiological understanding leads to insufficient treatment options associated with low survival rates for NEPC patients. Current treatments for NEPC, including platinum-based therapies, offer some efficacy, but there is a significant need for more targeted approaches. This review summarizes the molecular characteristics of NEPC in contrast to adeno-PCa, providing a comprehensive comparison. A significant portion of the discussion is dedicated to the tumor microenvironment (TME), which has recently been identified as a key factor in tumor progression. The TME includes various cells, signaling molecules, and the extracellular matrix surrounding the tumor, all of which play critical roles in cancer development and response to treatment. Understanding the TME's influence on NEPC could uncover new avenues for innovative treatment strategies, potentially improving outcomes for patients with this challenging variant of PCa.

Ubiquitin C-terminal hydrolase L1 is a regulator of tumor growth and metastasis in double-negative prostate cancer

Prostate cancer is the second leading cause of cancer-related deaths among men worldwide. With heavy androgen deprivation therapies, prostate cancer may shift to androgen receptor negative and neuroendocrine negative subtype of castration resistant prostate cancer, defined as double-negative prostate cancer. Double-negative prostate cancer is associated with poor prognosis and disease mortality. The molecular mechanisms underlying the emergence of double-negative prostate cancer remain poorly understood. Here, we demonstrate that Ubiquitin C-Terminal Hydrolase L1 (UCH-L1), is negatively correlated with androgen receptor levels in prostate cancer patients. UCH-L1 plays a functional role in tumorigenesis and metastasis in double-negative prostate cancer. Knock-down of UCH-L1 decreases double-negative prostate cancer colony formation in vitro and tumor growth in vivo. Moreover, decrease of UCH-L1 significantly delays cell migration in vitro and spontaneous metastasis and metastatic colonization in vivo. Proteomic analysis revealed that mTORC1 signaling, androgen response signaling and MYC targets are the top three decreased pathways upon UCH-L1 decrease. Further, treatment with LDN-57444, a UCH-L1 small molecule inhibitor, impairs double-negative prostate cancer cell colony formation, migration in vitro, and metastatic colonization in vivo. Our study reveals that UCH-L1 is an important regulator of double-negative prostate cancer tumor growth and progression, providing a promising therapeutic target for this subtype of metastatic prostate cancer.

Neuroendocrine transdifferentiation in human cancer: molecular mechanisms and therapeutic targets

Neuroendocrine transdifferentiation (NEtD), also commonly referred to as lineage plasticity, emerges as an acquired resistance mechanism to molecular targeted therapies in multiple cancer types, predominately occurs in metastatic epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer treated with EGFR tyrosine kinase inhibitors and metastatic castration-resistant prostate cancer treated with androgen receptor targeting therapies. NEtD tumors are the lethal cancer histologic subtype with unfavorable prognosis and limited treatment. A comprehensive understanding of molecular mechanism underlying targeted-induced plasticity could greatly facilitate the development of novel therapies. In the past few years, increasingly elegant studies indicated that NEtD tumors share key the convergent genomic and phenotypic characteristics irrespective of their site of origin, but also embrace distinct change and function of molecular mechanisms. In this review, we provide a comprehensive overview of the current understanding of molecular mechanism in regulating the NEtD, including genetic alterations, DNA methylation, histone modifications, dysregulated noncoding RNA, lineage-specific transcription factors regulation, and other proteomic alterations. We also provide the current management of targeted therapies in clinical and preclinical practice.

Unmasking Neuroendocrine Prostate Cancer with a Machine Learning-Driven 7-Gene Stemness Signature that Predicts Progression

Prostate cancer (PCa) poses a significant global health challenge, particularly due to its progression into aggressive forms like neuroendocrine prostate cancer (NEPC). This study developed and validated a stemness-associated gene signature using advanced machine learning techniques, including Random Forest and Lasso regression, applied to large-scale transcriptomic datasets. The resulting 7-gene signature (KMT5C, MEN1, TYMS, IRF5, DNMT3B, CDC25B and DPP4) was validated across independent cohorts and patient-derived xenograft (PDX) models. The signature demonstrated strong prognostic value for progression-free, disease-free, relapse-free, metastasis-free, and overall survival. Importantly, the signature not only identified specific NEPC subtypes, such as large-cell neuroendocrine carcinoma, which is associated with very poor outcomes, but also predicted a poor prognosis for PCa cases that exhibit this molecular signature, even when they were not histopathologically classified as NEPC. This dual prognostic and classifier capability makes the 7-gene signature a robust tool for personalized medicine, providing a valuable resource for predicting disease progression and guiding treatment strategies in PCa management.

Structural Optimization of Isoquinoline Derivatives from Lycobetaine and Their Inhibitory Activity against Neuroendocrine Prostate Cancer Cells

Neuroendocrine prostate cancer (NEPC) is a highly aggressive cancer that is resistant to hormone therapy and characterized by poor prognosis, as well as limited therapeutic options. Since the natural product lycobetaine was reported to exhibit good antitumor activities against various types of cancers, we initially simplified the scaffold of lycobetaine to obtain the active compound 1, an isoquinoline derivative with an aryl moiety substitution at the 4-position, which showed apparent antiproliferative activities against NPEC cell line LASCPC-01 in vitro. Subsequently, we carried out structural optimization and systematic structure-activity relationship (SAR) studies on compound 1, leading to the discovery of compound 46, which demonstrated potent inhibitory activities against the LASCPC-01 cell line with an IC50 value of 0.47 μM. Moreover, compound 46 displayed remarkable selectivity over prostate cancer cell line PC-3 with a selectivity index greater than 190-fold. Further cell-based mechanism studies revealed that compound 46 and lycobetaine can effectively induce G1 cell cycle arrest and apoptosis dose dependently. However, lycobetaine inhibited the expression of neuroendocrine markers, while compound 46 slightly upregulated these proteins. This suggested that compound 46 might exert its antitumor activities through a different mechanism than lycobetaine, warranting further study.

A Genome Wide CRISPR Screen Reveals That HOXA9 Promotes Enzalutamide Resistance in Prostate Cancer

Androgen receptor inhibitors are commonly used for prostate cancer treatment, but acquired resistance is a significant problem. Codeletion of RB and p53 is common in castration resistant prostate cancers, however they are difficult to target pharmacologically. To comprehensively identify gene loss events that contribute to enzalutamide response, we performed a genome-wide CRISPR knockout screen in LNCaP prostate cancer cells. This revealed novel genes implicated in resistance that are largely unstudied. Gene loss events that confer enzalutamide sensitivity are enriched for GSEA categories related to stem cell and epigenetic regulation. We investigated the myeloid lineage stem cell factor HOXA9 as a candidate gene whose loss promotes sensitivity to enzalutamide. Cancer genomic data reveals that HOXA9 overexpression correlates with poor prognosis and characteristics of advanced prostate cancer. In cell culture, HOXA9 depletion sensitizes cells to enzalutamide, whereas overexpression drives enzalutamide resistance. Combination of the HOXA9 inhibitor DB818 with enzalutamide demonstrates synergy. This demonstrates the utility of our CRISPR screen data in discovering new approaches for treating enzalutamide resistant prostate cancer.

Heat shock transcription factor 1 facilitates liver cancer progression by driving super-enhancer-mediated transcription of MYCN

BACKGROUND

Heat shock transcription factors (HSFs) play crucial roles in the development of malignancies. However, the specific roles of HSFs in hepatocellular carcinoma (HCC) have yet to be fully elucidated.

AIMS

To explore the involvement of the HSF family, particularly HSF1, in the progression and prognosis of HCC.

MATERIALS & METHODS

We conducted a thorough analysis of HSF expression and copy number variations across various cancer datasets. Specifically focusing on HSF1, we examined its expression levels and prognostic implications in HCC. In vitro and in vivo experiments were carried out to evaluate the impact of HSF1 on liver cancer cell proliferation. Additionally, we utilized CUT&Tag, H3K27 acetylation enrichment, and RNA sequencing (RNA-seq) to investigate the super-enhancer (SE) regulatory landscapes of HSF1 in liver cancer cell lines.

RESULTS

HSF1 expression is elevated in HCC and is linked to poor prognosis in several datasets. HSF1 stimulates liver cancer cell proliferation both in vitro and in vivo, partly through modulation of H3K27ac levels, influencing enhancer distribution. Mechanistically, our findings demonstrate that HSF1 transcriptionally activates MYCN expression by binding to its promoter and SE elements, thereby promoting liver cancer cell proliferation. Moreover, increased MYCN expression was detected in HCC tumors and correlated with unfavorable patient outcomes.

DISCUSSION

Our study sheds light on previously unexplored aspects of HSF1 biology, identifying it as a transcription factor capable of shaping the epigenetic landscape in the context of HCC. Given HSF1's potential as an epigenetic regulator, targeting the HSF1-MYCN axis could open up new therapeutic possibilities for HCC treatment.

CONCLUSION

The HSF1-MYCN axis constitutes a transcription-dependent regulatory mechanism that may function as both a prognostic indicator and a promising therapeutic target in liver cancer. Further exploration of this axis could yield valuable insights into novel treatment strategies for HCC.

A forward genetic screen identifies Sirtuin1 as a driver of neuroendocrine prostate cancer

Although localized prostate cancer is relatively indolent, advanced prostate cancer manifests with aggressive and often lethal variants, including neuroendocrine prostate cancer (NEPC). To identify drivers of aggressive prostate cancer, we leveraged Sleeping Beauty (SB) transposon mutagenesis in a mouse model based on prostate-specific loss-of-function of Pten and Tp53 . Compared with control mice, SB mice developed more aggressive prostate tumors, with increased incidence of metastasis. Notably, a significant percentage of the SB prostate tumors display NEPC phenotypes, and the transcriptomic features of these SB mouse tumors recapitulated those of human NEPC. We identified common SB transposon insertion sites (CIS) and prioritized associated CIS-genes differentially expressed in NEPC versus non-NEPC SB tumors. Integrated analysis of CIS-genes encoding for proteins representing upstream, post-translational modulators of master regulators controlling the transcriptional state of SB -mouse and human NEPC tumors identified sirtuin 1 ( Sirt1 ) as a candidate mechanistic determinant of NEPC. Gain-of-function studies in human prostate cancer cell lines confirmed that SIRT1 promotes NEPC, while its loss-of-function or pharmacological inhibition abrogates NEPC. This integrative analysis is generalizable and can be used to identify novel cancer drivers for other malignancies.

Summary

Using an unbiased forward mutagenesis screen in an autochthonous mouse model, we have investigated mechanistic determinants of aggressive prostate cancer. SIRT1 emerged as a key regulator of neuroendocrine prostate cancer differentiation and a potential target for therapeutic intervention.

An identity crisis for lung cancer cells

Omic analysis of clinical specimens undergoing histological transformation defines targetable drivers to prevent plasticity and treatment resistance.

Promising therapy for neuroendocrine prostate cancer: current status and future directions

Neuroendocrine prostate cancer (NEPC) is a highly aggressive variant of castration-resistant prostate cancer. It is characterized by low or no expression of the androgen receptor (AR), activation of AR-independent signaling, and increased neuroendocrine phenotype. Most of NEPC is induced by treatment of androgen deprivation therapy and androgen receptor pathway inhibitors (ARPIs). Currently, the treatment of NEPC follows the treatment strategy for small-cell lung cancer, lacking effective drugs and specific treatment options. This review summarizes potential novel targets and therapies for NEPC treatment, including epigenetic regulators (zeste homolog 2 inhibitors, lysine-specific demethylase 1 inhibitors), aurora kinase A inhibitors, poly-ADP-ribose polymerase inhibitors, delta-like ligand 3 targeted therapies, a combination of immunotherapies, etc. Other promising targets and future directions are also discussed in this review. These novel targets and therapies may provide new opportunities for the treatment of NEPC.

ZNF397 Deficiency Triggers TET2-Driven Lineage Plasticity and AR-Targeted Therapy Resistance in Prostate Cancer

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.

Notch signaling suppresses neuroendocrine differentiation and alters the immune microenvironment in advanced prostate cancer

Notch signaling can have either an oncogenic or tumor-suppressive function in cancer depending on the cancer type and cellular context. While Notch can be oncogenic in early prostate cancer, we identified significant downregulation of the Notch pathway during prostate cancer progression from adenocarcinoma to neuroendocrine (NE) prostate cancer, where it functions as a tumor suppressor. Activation of Notch in NE and Rb1/Trp53-deficient prostate cancer models led to phenotypic conversion toward a more indolent, non-NE state with glandular features and expression of luminal lineage markers. This was accompanied by upregulation of MHC and type I IFN and immune cell infiltration. Overall, these data support Notch signaling as a suppressor of NE differentiation in advanced prostate cancer and provide insights into how Notch signaling influences lineage plasticity and the tumor microenvironment (TME).

Diverse landscape of genetically engineered mouse models: Genomic and molecular insights into prostate cancer

Prostate cancer (PCa) is a significant health concern for men worldwide and is particularly prevalent in the United States. It is a complex disease presenting different molecular subtypes and varying degrees of aggressiveness. Transgenic/genetically engineered mouse models (GEMMs) greatly enhanced our understanding of the intricate molecular processes that underlie PCa progression and have offered valuable insights into potential therapeutic targets for this disease. The integration of whole-exome and whole-genome sequencing, along with expression profiling, has played a pivotal role in advancing GEMMs by facilitating the identification of genetic alterations driving PCa development. This review focuses on genetically modified mice classified into the first and second generations of PCa models. We summarize whether models created by manipulating the function of specific genes replicate the consequences of genomic alterations observed in human PCa, including early and later disease stages. We discuss cases where GEMMs did not fully exhibit the expected human PCa phenotypes and possible causes of the failure. Here, we summarize the comprehensive understanding, recent advances, strengths and limitations of the GEMMs in advancing our insights into PCa, offering genetic and molecular perspectives for developing novel GEMM models.

Discovery of a peptide proteolysis-targeting chimera (PROTAC) drug of p300 for prostate cancer therapy

BACKGROUND

The E1A-associated protein p300 (p300) has emerged as a promising target for cancer therapy due to its crucial role in promoting oncogenic signaling pathways in various cancers, including prostate cancer. This need is particularly significant in prostate cancer. While androgen deprivation therapy (ADT) has demonstrated promising efficacy in prostate cancer, its long-term use can eventually lead to the development of castration-resistant prostate cancer (CRPC) and neuroendocrine prostate cancer (NEPC). Notably, p300 has been identified as an important co-activator of the androgen receptor (AR), highlighting its significance in prostate cancer progression. Moreover, recent studies have revealed the involvement of p300 in AR-independent oncogenes associated with NEPC. Therefore, the blockade of p300 may emerge as an effective therapeutic strategy to address the challenges posed by both CRPC and NEPC.

METHODS

We employed AI-assisted design to develop a peptide-based PROTAC (proteolysis-targeting chimera) drug that targets p300, effectively degrading p300 in vitro and in vivo utilizing nano-selenium as a peptide drug delivery system.

FINDINGS

Our p300-targeting peptide PROTAC drug demonstrated effective p300 degradation and cancer cell-killing capabilities in both CRPC, AR-negative, and NEPC cells. This study demonstrated the efficacy of a p300-targeting drug in NEPC cells. In both AR-positive and AR-negative mouse models, the p300 PROTAC drug showed potent p300 degradation and tumor suppression.

INTERPRETATION

The design of peptide PROTAC drug targeting p300 is feasible and represents an efficient therapeutic strategy for CRPC, AR-negative prostate cancer, and NEPC.

FUNDING

The funding details can be found in the Acknowledgements section.

Epigenetic regulation of androgen dependent and independent prostate cancer

Prostate cancer is one of the most common malignancies among men worldwide. Besides genetic alterations, epigenetic modulations including DNA methylation, histone modifications and miRNA mediated alteration of gene expression are the key driving forces for the prostate tumor development and cancer progression. Aberrant expression and/or the activity of the epigenetic modifiers/enzymes, results in aberrant expression of genes involved in DNA repair, cell cycle regulation, cell adhesion, apoptosis, autophagy, tumor suppression and hormone response and thereby disease progression. Altered epigenome is associated with prostate cancer recurrence, progression, aggressiveness and transition from androgen-dependent to androgen-independent phenotype. These epigenetic modifications are reversible and various compounds/drugs targeting the epigenetic enzymes have been developed that are effective in cancer treatment. This chapter focuses on the epigenetic alterations in prostate cancer initiation and progression, listing different epigenetic biomarkers for diagnosis and prognosis of the disease and their potential as therapeutic targets. This chapter also summarizes different epigenetic drugs approved for prostate cancer therapy and the drugs available for clinical trials.