SOX2 promotes lineage plasticity and antiandrogen resistance in TP53- and RB1-deficient prostate cancer

Molecular Landscape of Aggressive Histologic Subtypes of Localized Prostate Cancer

Despite incredible progress in describing the molecular underpinnings of prostate cancer over the last decades, pathologic examination remains indispensable for predicting aggressive behavior in the localized setting. Beyond pathologic grade, specific histologic findings have emerged as critical prognostic or predictive indicators. Here, the authors review molecular correlates of aggressive histologic subtypes of prostate cancer in the localized setting, demonstrating that many of the signature molecular alterations found in metastatic disease-such as tumor suppressor gene loss and DNA repair defects-are enriched in primary disease with adverse histologic features, presaging aggressive behavior, and presenting opportunities for earlier germline screening or targeted therapies.

Identification of selective SWI/SNF dependencies in enzalutamide-resistant prostate cancer

Enzalutamide is a potent second-generation antiandrogen commonly used to treat hormone-sensitive and castration-resistant prostate cancer (CRPC) patients. While initially effective, the disease almost always develops resistance. Given that many enzalutamide-resistant tumors lack specific somatic mutations, there is strong evidence that epigenetic factors can cause enzalutamide resistance. To explore how resistance arises, we systematically test all epigenetic modifiers in several models of castration-resistant and enzalutamide-resistant prostate cancer with a custom epigenetic CRISPR library. From this, we identify and validate SMARCC2, a core component of the SWI/SNF complex, that is selectivity essential in enzalutamide-resistant models. We show that the chromatin occupancy of SMARCC2 and BRG1 is expanded in enzalutamide resistance at regions that overlap with CRPC-associated transcription factors that are accessible in CRPC clinical samples. Overall, our study reveals a regulatory role for SMARCC2 in enzalutamide-resistant prostate cancer and supports the feasibility of targeting the SWI/SNF complex in late-stage PCa.

Framework for the Pathology Workup of Metastatic Castration-Resistant Prostate Cancer Biopsies

Lineage plasticity and histologic transformation from prostate adenocarcinoma to neuroendocrine (NE) prostate cancer (NEPC) occur in up to 15% to 20% of patients with castration-resistant prostate cancer (CRPC) as a mechanism of treatment resistance and are associated with aggressive disease and poor prognosis. NEPC tumors typically display small cell carcinoma morphology with loss of androgen receptor (AR) expression and gain of NE lineage markers. However, there is a spectrum of phenotypes that are observed during the lineage plasticity process, and the clinical significance of mixed histologies or those that co-express AR and NE markers or lack all markers is not well defined. Translational research studies investigating NEPC have used variable definitions, making clinical trial design challenging. In this manuscript, we discuss the diagnostic workup of metastatic biopsies to help guide the reproducible classification of phenotypic CRPC subtypes. We recommend classifying CRPC tumors based on histomorphology (adenocarcinoma, small cell carcinoma, poorly differentiated carcinoma, other morphologic variant, or mixed morphology) and IHC markers with a priority for AR, NK3 homeobox 1, insulinoma-associated protein 1, synaptophysin, and cell proliferation based on Ki-67 positivity, with additional markers to be considered based on the clinical context. Ultimately, a unified workup of metastatic CRPC biopsies can improve clinical trial design and eventually practice.

Epigenomics-guided precision oncology: Chromatin variants in prostate tumor evolution

Prostate cancer is a common malignancy that in 5%-30% leads to treatment-resistant and highly aggressive disease. Metastasis-potential and treatment-resistance is thought to rely on increased plasticity of the cancer cells-a mechanism whereby cancer cells alter their identity to adapt to changing environments or therapeutic pressures to create cellular heterogeneity. To understand the molecular basis of this plasticity, genomic studies have uncovered genetic variants to capture clonal heterogeneity of primary tumors and metastases. As cellular plasticity is largely driven by non-genetic events, complementary studies in cancer epigenomics are now being conducted to identify chromatin variants. These variants, defined as genomic loci in cancer cells that show changes in chromatin state due to the loss or gain of epigenomic marks, inclusive of histone post-translational modifications, DNA methylation and histone variants, are considered the fundamental units of epigenomic heterogeneity. In prostate cancer chromatin variants hold the promise of guiding the new era of precision oncology. In this review, we explore the role of epigenomic heterogeneity in prostate cancer, focusing on how chromatin variants contribute to tumor evolution and therapy resistance. We therefore discuss their impact on cellular plasticity and stochastic events, highlighting the value of single-cell sequencing and liquid biopsy epigenomic assays to uncover new therapeutic targets and biomarkers. Ultimately, this review aims to support a new era of precision oncology, utilizing insights from epigenomics to improve prostate cancer patient outcomes.

The Homeobox Transcription Factor NKX3.1 Displays an Oncogenic Role in Castration-Resistant Prostate Cancer Cells

BACKGROUND/OBJECTIVES

Prostate cancer (PCa) is the second leading cause of cancer-related death in men. The increase in incidence rates of more advanced and aggressive forms of the disease year-to-year fuels urgency to find new therapeutic interventions and bolster already established ones. PCa is a uniquely targetable disease in that it is fueled by male hormones (androgens) that drive tumorigenesis via the androgen receptor or AR. Current standard-of-care therapies directly target AR and its aberrant signaling axis but resistance to these therapies commonly arises, and the mechanisms behind the onset of therapy-resistance are still elusive. Research has shown that even with resistant disease, AR remains the main driver of growth and survival of PCa, and AR target genes and cofactors may help mediate resistance to therapy. Here, we focused on a homeobox transcription factor that exhibits a close relationship with AR-NKX3.1. Though NKX3.1 is traditionally thought of as a tumor suppressor, it has been previously reported to promote cancer cell survival by cooperating with AR. The role of NKX3.1 as a tumor suppressor perhaps in early-stage disease also contradicts its profile as a diagnostic biomarker for advanced prostate cancer.

METHODS

We investigated the physical interaction between NKX3.1 and AR, a modulated NKX3.1 expression in prostate cancer cells via overexpression and knockdown and assayed subsequent viability and downstream target gene expression.

RESULTS

We find that the expression of NKX3.1 is maintained in advanced PCa, and it is often elevated because of aberrant AR activity. Transient knockdown experiments across various PCa cell line models reveal NKX3.1 expression is necessary for survival. Similarly, stable overexpression of NKX3.1 in PCa cell lines reveals an androgen insensitive phenotype, suggesting NKX3.1 is sufficient to promote growth in the absence of an AR ligand.

CONCLUSIONS

Our work provides new insight into NKX3.1's oncogenic influence on PCa and the molecular interplay of these transcription factors in models of late-stage prostate cancer.

Neuroendocrine Transformation as a Mechanism of Resistance to Targeted Lung Cancer Therapies: Emerging Mechanisms and Their Therapeutic Implications

Lung cancer is the leading cause of cancer-related deaths worldwide, highlighting a major clinical challenge. Lung cancer is broadly classified into two histologically distinct subtypes, termed small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC). Identification of various oncogenic drivers of NSCLC has facilitated the development of targeted therapies that have dramatically improved patient outcomes. However, acquired resistance to these targeted therapies is common, which ultimately results in patient relapse. Several on-target and off-target resistance mechanisms have been described for targeted therapies in NSCLC. One common off-target mechanism of resistance to these therapies is histological transformation of the initial NSCLC into SCLC, a highly aggressive form of lung cancer that exhibits neuroendocrine histology. This mechanism of resistance presents a significant clinical challenge, since there are very few treatments available for these relapsed patients. Although the phenomenon of NSCLC-to-SCLC transformation was described almost 20 years ago, only recently have we begun to understand the mechanisms underlying this therapy-driven response. These recent discoveries will be key to identifying novel biomarkers and therapeutic strategies to improve outcomes of patients that undergo NSCLC-to-SCLC transformation. Here, we highlight these recent advances and discuss the potential therapeutic strategies that they have uncovered to target this mechanism of resistance.

Epigenomic heterogeneity as a source of tumour evolution

In the past decade, remarkable progress in cancer medicine has been achieved by the development of treatments that target DNA sequence variants. However, a purely genetic approach to treatment selection is hampered by the fact that diverse cell states can emerge from the same genotype. In multicellular organisms, cell-state heterogeneity is driven by epigenetic processes that regulate DNA-based functions such as transcription; disruption of these processes is a hallmark of cancer that enables the emergence of defective cell states. Advances in single-cell technologies have unlocked our ability to quantify the epigenomic heterogeneity of tumours and understand its mechanisms, thereby transforming our appreciation of how epigenomic changes drive cancer evolution. This Review explores the idea that epigenomic heterogeneity and plasticity act as a reservoir of cell states and therefore as a source of tumour evolution. Best practices to quantify epigenomic heterogeneity and explore its various causes and consequences are discussed, including epigenomic reprogramming, stochastic changes and lasting memory. The design of new therapeutic approaches to restrict epigenomic heterogeneity, with the long-term objective of limiting cancer development and progression, is also addressed.

The Emerging Predictive and Prognostic Role of Aggressive-Variant-Associated Tumor Suppressor Genes Across Prostate Cancer Stages

Aggressive variant prostate cancer (AVPC) is characterized by a molecular signature involving combined defects in TP53, RB1, and/or PTEN (AVPC-TSGs), identifiable through immunohistochemistry or genomic analysis. The reported prevalence of AVPC-TSG alterations varies widely, reflecting differences in assay sensitivity, treatment pressure, and disease stage evolution. Although robust clinical evidence is still emerging, the study of AVPC-TSG alterations in prostate cancer (PCa) is promising. Alterations in TP53, RB1, and PTEN, as well as the combined loss of AVPC-TSGs, may have significant implications for prognosis and treatment. These biomarkers might help predict responses to various therapies, including hormonal treatments, cytotoxic agents, radiotherapy, and targeted therapies. Understanding the impact of these molecular alterations in patients with PCa is crucial for personalized management. In this review, we provide a comprehensive overview of the emerging prognostic and predictive roles of AVPC-TSG alterations across PCa stages. Moreover, we discuss the implications of different methods used for detecting AVPC-TSG alterations and summarize factors influencing their prevalence. As our comprehension of the genomic landscape of PCa disease deepens, incorporating genomic profiling into clinical decision making will become increasingly important for improving patient outcomes.

Single-Cell RNA Sequencing Reveals the Cellular Origin and Evolution of Small-Cell Neuroendocrine Carcinoma of the Cervix

Small-cell neuroendocrine cancer (SCNEC) of the uterine cervix is an exceedingly rare, highly aggressive tumor with an extremely poor prognosis. The cellular heterogeneity, origin, and tumorigenesis trajectories of SCNEC of the cervix remain largely unclear. We performed single-cell RNA sequencing and whole-exome sequencing on tumor tissues and adjacent normal cervical tissues from two patients diagnosed with SCNEC of the cervix. Here, we provide the first comprehensive insights into the cellular composition, HPV infection-related features, and gene expression profiles of SCNEC of the cervix at single-cell resolution. Correlation analyses suggested that SCNEC of the cervix may originate from squamous epithelial cells, and this observation was validated with bulk RNA-seq data from external cervical neuroendocrine cancer. Furthermore, sex-determining region Y-box 2 (SOX2), a key transcription factor that functions in direct neural differentiation, was located in the copy number gain region and highly expressed in neuroendocrine tumor cells from both patients. Notable, the distributions of the HPV-infected epithelium and SOX2 highly expressed epithelium were consistent with each other. Therefore, we supposed that high-risk HPV infection and amplification of SOX2 in the squamous epithelium may contribute to the progression of small-cell neuroendocrine tumorigenesis in the cervix.

Prostate Luminal Cell Plasticity and Cancer

Cellular plasticity in prostate cancer promotes treatment resistance. Several independent studies have used mouse models, single-cell RNA sequencing, and genetic lineage tracing approaches to characterize cellular differentiation and plasticity during prostate organogenesis, homeostasis and androgen-mediated tissue regeneration. We review these findings and recent work using immune-competent genetically-engineered mouse models to characterize cellular plasticity and clonal dynamic changes during prostate cancer progression. Collectively these studies highlight the influence of the tumor microenvironment and the function of epigenetic regulators in promoting cellular plasticity. How the epigenetic alternations that promote cell plasticity affect tumor immunogenicity remains an active area of research with implications for disease treatment.

Exosome-delivered NR2F1-AS1 and NR2F1 drive phenotypic transition from dormancy to proliferation in treatment-resistant prostate cancer via stabilizing hormonal receptors

Cancer cells acquire the ability to reprogram their phenotype in response to targeted therapies, yet the transition from dormancy to proliferation in drug-resistant cancers remains poorly understood. In prostate cancer, we utilized high-plasticity mouse models and enzalutamide-resistant (ENZ-R) cellular models to elucidate NR2F1 as a key factor in lineage transition and ENZ resistance. Depletion of NR2F1 drives ENZ-R cells into a relative dormancy state, characterized by reduced proliferation and heightened drug resistance, while NR2F1 overexpression yields contrasting outcomes. Transcriptional sequencing analysis of NR2F1-silenced prostate cancer cells and tissues from the Cancer Genome Atlas-prostate cancer and SU2C cohorts indicated exosomes as the most enriched cell component, with pathways implicated in steroid hormone biosynthesis and drug metabolism. Moreover, NR2F1-AS1 forms a complex with SRSF1 to upregulate NR2F1 expression, facilitating its binding with ESR1 to sustain hormonal receptor expression and enhance proliferation in ENZ-R cells. Furthermore, HnRNPA2B1 interacts with NR2F1 and NR2F1-AS1, assisting their packaging into exosomes, wherein exosomal NR2F1 and NR2F1-AS1 promote the proliferation of dormant ENZ-R cells. Our works offer novel insights into the reawaking of dormant drug-resistant cancer cells governed by NR2F1 upregulation triggered by exosome-derived NR2F1-AS1 and NR2F1, suggesting therapeutic potential for phenotype reversal.

Mitochondrial unfolded protein response-dependent β-catenin signaling promotes neuroendocrine prostate cancer

The mitochondrial unfolded protein response (UPRmt) maintains mitochondrial quality control and proteostasis under stress conditions. However, the role of UPRmt in aggressive and resistant prostate cancer is not clearly defined. We show that castration-resistant neuroendocrine prostate cancer (CRPC-NE) harbored highly dysfunctional oxidative phosphorylation (OXPHOS) Complexes. However, biochemical and protein analyses of CRPC-NE tumors showed upregulation of nuclear-encoded OXPHOS proteins and UPRmt in this lethal subset of prostate cancer suggestive of compensatory upregulation of stress signaling. Genetic deletion and pharmacological inhibition of the main chaperone of UPRmt heat shock protein 60 (HSP60) reduced neuroendocrine prostate cancer (NEPC) growth in vivo as well as reverted NEPC cells to a more epithelial-like state. HSP60-dependent aggressive NEPC phenotypes was associated with upregulation of β-catenin signaling both in cancer cells and in vivo tumors. HSP60 expression rendered enrichment of aggressive prostate cancer signatures and metastatic potential were inhibited upon suppression of UPRmt. We discovered that UPRmt promoted OXPHOS functions including mitochondrial bioenergetics in CRPC-NE via regulation of β-catenin signaling. Mitochondrial biogenesis facilitated cisplatin resistance and inhibition of UPRmt resensitizes CRPC-NE cells to cisplatin. Together, our findings demonstrated that UPRmt promotes mitochondrial health via upregulating β-catenin signaling and UPRmt represents viable therapeutic target for NEPC.

SOX2 control activation of dormant prostate cancer cells in bone metastases by promoting CCNE2 gene expression

BACKGROUND

Cancer stem cells (CSCs) have a powerful tumor initiation ability, which can promote the early dissemination of single disseminated tumor cells (DTCs), leading to tumor progression. SOX2, a pluripotent inducible transcription factor, is key to maintaining self-renewal and pluripotency of prostate cancer stem cells. However, there is a lack of comprehensive understanding of how SOX2 regulates DTCs dormancy and proliferation in the bone marrow microenvironment.

METHODS AND RESULTS

By constructing a mouse bone metastasis model to simulate the progression of prostate cancer with bone metastasis, the bone tissue immunofluorescence showed that SOX2 expression increased with the progression of prostate cancer in the bone marrow microenvironment. We validated this phenomenon with publicly available single-cell and transcriptome datasets and found that SOX2 is involved in multiple phenotypes associated with prostate cancer dormancy, proliferation, and invasion. Further, CCNE2, a potential target downstream of SOX2, was identified through multiple transcription factor databases and protein interaction networks.

CONCLUSION

The expression of SOX2 affects multiple phenotypes related to dormancy, proliferation and invasion of prostate cancer, and may indirectly activate the dormant prostate cancer cells through the downstream target gene CCNE2, thus affecting the progression and bone metastasis of prostate cancer.

Impact of cell plasticity on prostate tumor heterogeneity and therapeutic response

Epithelial-mesenchymal transition (EMT) is a dynamic process of lineage plasticity in which epithelial cancer cells acquire mesenchymal traits, enabling them to metastasize to distant organs. This review explores the current understanding of how lineage plasticity and phenotypic reprogramming drive prostate cancer progression to lethal stages, contribute to therapeutic resistance, and highlight strategies to overcome the EMT phenotype within the prostate tumor microenvironment (TME). Emerging evidence reveals that prostate tumor cells can undergo lineage switching, adopting alternative growth pathways in response to anti-androgen therapies and taxane-based chemotherapy. These adaptive mechanisms support tumor survival and growth, underscoring the need for deeper insights into the processes driving prostate cancer differentiation, including neuroendocrine differentiation and lineage plasticity. A comprehensive understanding of these mechanisms will pave the way for innovative therapeutic strategies. Effectively targeting prostate cancer cells with heightened plasticity and therapeutic vulnerability holds promise for overcoming treatment resistance and preventing tumor recurrence. Such advancements are critical for developing effective approaches to prostate cancer treatment and improving patient survival outcomes.

Triplet therapy for metastatic castration-sensitive prostate cancer: Rationale and clinical evidence

Prostate cancer (PC) growth is hormone-dependent and it frequently develops distant metastases as disease progresses. Patients with metastatic castration-sensitive prostate cancer (mCSPC) initially respond to androgen deprivation therapy (ADT) but eventually become refractory and develop metastatic castration-resistant prostate cancer (mCRPC). Castration-resistance is associated with high lethality and metastases confer poor prognosis, therefore unmet needs in treatment for mCSPC remain high. So far, improvements in survival in mCSPC have been achieved by doublet combination therapy such as docetaxel or an androgen-receptor signaling inhibitor (ARSI) in addition to ADT. Further, recent phase 3 trials have shown that triplet therapy-a combination of ARSI, docetaxel, and ADT improves prognosis compared with docetaxel plus ADT in mCSPC. PC tumors manifest intra- and inter-tumoral heterogeneity at both the genetic and phenotypic level. As heterogeneity increases during sequential treatment and disease progression, it is reasonable to initiate combination therapy using drugs with different mechanisms of action early in the course of disease, such as mCSPC. Previous research about tumor heterogeneity and drug resistant mechanism support this rationale, as well as preclinical studies and real-world data provide the scientific evidence of benefit by combining ARSI and docetaxel. Here, we review the rationale and clinical evidence for triplet therapy in patients with mCSPC.

PGC-1α drives small cell neuroendocrine cancer progression toward an ASCL1-expressing subtype with increased mitochondrial capacity

Adenocarcinomas from multiple tissues can converge to treatment-resistant small cell neuroendocrine (SCN) cancers composed of ASCL1, POU2F3, NEUROD1, and YAP1 subtypes. We investigated how mitochondrial metabolism influences SCN cancer (SCNC) progression. Extensive bioinformatics analyses encompassing thousands of patient tumors and human cancer cell lines uncovered enhanced expression of proliferator-activatedreceptor gamma coactivator 1-alpha (PGC-1α), a potent regulator of mitochondrial oxidative phosphorylation (OXPHOS), across several SCNCs. PGC-1α correlated tightly with increased expression of the lineage marker Achaete-scute homolog 1, (ASCL1) through a positive feedback mechanism. Analyses using a human prostate tissue-based SCN transformation system showed that the ASCL1 subtype has heightened PGC-1α expression and OXPHOS activity. PGC-1α inhibition diminished OXPHOS, reduced SCNC cell proliferation, and blocked SCN prostate tumor formation. Conversely, PGC-1α overexpression enhanced OXPHOS, validated by small-animal Positron Emission Tomography mitochondrial imaging, tripled the SCN prostate tumor formation rate, and promoted commitment to the ASCL1 lineage. These results establish PGC-1α as a driver of SCNC progression and subtype determination, highlighting metabolic vulnerabilities in SCNCs across different tissues.

Reciprocal inhibition of NOTCH and SOX2 shapes tumor cell plasticity and therapeutic escape in triple-negative breast cancer

Cancer cell plasticity contributes significantly to the failure of chemo- and targeted therapies in triple-negative breast cancer (TNBC). Molecular mechanisms of therapy-induced tumor cell plasticity and associated resistance are largely unknown. Using a genome-wide CRISPR-Cas9 screen, we investigated escape mechanisms of NOTCH-driven TNBC treated with a gamma-secretase inhibitor (GSI) and identified SOX2 as a target of resistance to Notch inhibition. We describe a novel reciprocal inhibitory feedback mechanism between Notch signaling and SOX2. Specifically, Notch signaling inhibits SOX2 expression through its target genes of the HEY family, and SOX2 inhibits Notch signaling through direct interaction with RBPJ. This mechanism shapes divergent cell states with NOTCH positive TNBC being more epithelial-like, while SOX2 expression correlates with epithelial-mesenchymal transition, induces cancer stem cell features and GSI resistance. To counteract monotherapy-induced tumor relapse, we assessed GSI-paclitaxel and dasatinib-paclitaxel combination treatments in NOTCH inhibitor-sensitive and -resistant TNBC xenotransplants, respectively. These distinct preventive combinations and second-line treatment option dependent on NOTCH1 and SOX2 expression in TNBC are able to induce tumor growth control and reduce metastatic burden.

L1CAM mediates neuroendocrine phenotype acquisition in prostate cancer cells

BACKGROUND

A specific type of prostate cancer (PC) that exhibits neuroendocrine (NE) differentiation is known as NEPC. NEPC has little to no response to androgen deprivation therapy and is associated with the development of metastatic castration-resistant PC (CRPC), which has an extremely poor prognosis. Our understanding of genetic drivers and activated pathways in NEPC is limited, which hinders precision medicine approaches. L1 cell adhesion molecule (L1CAM) is known to play an oncogenic role in metastatic cancers, including CRPC. However, the impact of L1CAM on NEPC progression remains elusive.

METHODS

L1CAM expression level was investigated using public gene expression databases of PC cohorts and patient-derived xenograft models. L1CAM knockdown was performed in different PC cells to study in vitro cell functions. A subline of CRPC cell line CWR22Rv1 was established after long-term exposure to abiraterone to induce NE differentiation. The androgen receptor-negative cell line PC3 was cultured under the tumor sphere-forming condition to enrich cancer stemness features. Several oxidative stress inducers were tested on PC cells to observe L1CAM-mediated gene expression and cell death.

RESULTS

L1CAM expression was remarkably high in NEPC compared to CRPC or adenocarcinoma tumors. L1CAM was also correlated with NE marker expressions and associated with the adenocarcinoma-to-NEPC progression in gene expression databases and CRPC cells with NE differentiation. L1CAM also promoted cancer stemness and NE phenotypes in PC3 cells under cancer stemness enrichment. L1CAM was also identified as a reactive oxygen species-induced gene, by which L1CAM counteracted CRPC cell death triggered by ionizing radiation.

CONCLUSIONS

Our results unveiled a new role of L1CAM in the acquisition of the NE phenotype in PC, contributing to the NE differentiation-related therapeutic resistance of CRPC.

JAK/STAT signaling maintains an intermediate cell population during prostate basal cell fate determination

Unipotent basal and luminal stem cells maintain prostate homeostasis, with an intermediate cell population emerging during prostate inflammation or cancer. However, the identities of basal stem cell and intermediate cell population remain unclear. Here we identified a rare intermediate cell population expressing luminal markers (termed Basal-B) with enhanced organoid formation capacity, and a larger basal population (termed Basal-A). Genetic lineage tracing revealed Basal-B cells represented a transient basal stem cell state during prostate homeostasis and androgen-mediated regeneration. Activated JAK/STAT signaling was identified in Basal-B cells, and its inhibition significantly reduced Basal-B markers expression. Inflammation increased Basal-B-to-luminal cell transdifferentiation, but JAK/STAT inhibition notably attenuated this effect. Pten gene deletion increased Nkx3.1-expressing Basal-B-like cell population and led to neoplasia. In humans, h-Basal-B cells were more prevalent in benign prostate hyperplasia. This study reveals the identities of intermediate Basal-B cells and underscores the role of JAK/STAT signaling in prostate cell fate determination.

Integrative analysis identifies the atypical repressor E2F8 as a targetable transcriptional activator driving lethal prostate cancer

Acquired resistance to androgen receptor (AR)-targeted therapies underscores the need to identify alternative therapeutic targets for treating lethal prostate cancer. In this study, we evaluated the prognostic significance of 1635 human transcription factors (TFs) by analyzing castration-resistant prostate cancer (CRPC) datasets from the West and East Stand Up to Cancer (SU2C) cohorts. Through this screening approach, we identified E2F8, a putative transcriptional repressor, as a TF consistently associated with poorer patient outcomes in both cohorts. Notably, E2F8 is highly expressed and active in AR-negative CRPC compared to AR-positive CRPC. Integrative profiling of E2F8 cistromes and transcriptomes in AR-negative CRPC cells revealed that E2F8 directly and non-canonically activates target oncogenes involved in cancer-associated pathways. To target E2F8 in CRPC, we employed the CRISPR/CasRx system to knockdown E2F8 mRNA, resulting in effective and specific downregulation of E2F8 and its target oncogenes, as well as significant growth inhibition in AR-negative CRPC in both cultured cells and xenograft models. Our findings identify and characterize E2F8 as a targetable transcriptional activator driving CRPC, particularly the growth of AR-negative CRPC.

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.

Low tristetraprolin expression activates phenotypic plasticity and primes transition to lethal prostate cancer in mice

Phenotypic plasticity is a hallmark of cancer and is increasingly realized as a mechanism of resistance to androgen receptor-targeted (AR-targeted) therapy. Now that many prostate cancer (PCa) patients are treated upfront with AR-targeted agents, it is critical to identify actionable mechanisms that drive phenotypic plasticity, to prevent the emergence of resistance. We showed that loss of tristetraprolin (TTP; gene ZFP36) increased NF-κB activation, and was associated with higher rates of aggressive disease and early recurrence in primary PCa. We also examined the clinical and biological impact of ZFP36 loss with co-loss of PTEN, a known driver of PCa. Analysis of multiple independent primary PCa cohorts demonstrated that PTEN and ZFP36 co-loss was associated with increased recurrence risk. Engineering prostate-specific Zfp36 deletion in vivo induced prostatic intraepithelial neoplasia, and, with Pten codeletion, resulted in rapid progression to castration-resistant adenocarcinoma. Zfp36 loss altered the cell state driven by Pten loss, as demonstrated by enrichment of epithelial-mesenchymal transition (EMT), inflammation, TNF-α/NF-κB, and IL-6-JAK/STAT3 gene sets. Additionally, our work revealed that ZFP36 loss also induced enrichment of multiple gene sets involved in mononuclear cell migration, chemotaxis, and proliferation. Use of the NF-κB inhibitor dimethylaminoparthenolide (DMAPT) induced marked therapeutic responses in tumors with PTEN and ZFP36 co-loss and reversed castration resistance.

The long noncoding RNA MIR4435-2HG enhances the migration, promotion, and glycolysis of nonsmall cell lung cancer cells by targeting the miR-371a-5p/SOX2/PI3K/Akt axis

Background

Nonsmall cell lung cancer is a leading cause of cancer-related death worldwide. The long noncoding RNA MIR4435-2HG has been shown to play a carcinogenic role in various cancers. The purpose of this study was to explore the role and regulatory mechanism of MIR4435-2HG in non-small cell lung cancer.

Methods

Quantitative real-time polymerase chain reaction was used to detect MIR4435-2HG and SRY-box transcription factor 2 in nonsmall cell lung cancer cells. Gain- or loss-of-function assays of MIR4435-2HG and SRY-box transcription factor 2 were subsequently conducted. Cell proliferation, apoptosis, migration, glycolysis, and invasion were tested. A nude mouse tumor model was constructed to determine the role of MIR4435-2HG and SRY-box transcription factor 2 in the growth of tumor cells in vivo. Furthermore, the interactions between MIR4435-2HG, miR-371a-5p and SRY-box transcription factor 2 were analyzed via a dual-luciferase reporter gene assay.

Results

Quantitative real-time polymerase chain reaction revealed that MIR4435-2HG and SRY-box transcription factor 2 were upregulated in nonsmall cell lung cancer cells. Forced MIR4435-2HG overexpression led to increased cell proliferation, migration, invasion, and glycolysis and repressed cell apoptosis. Overexpressing MIR4435-2HG promoted SRY-box transcription factor 2 expression and PI3K/Akt/mTOR pathway activation. Downregulating MIR4435-2HG had antitumor effects both in vitro and in vivo. SRY-box transcription factor 2 overexpression mostly reversed the suppressive effects of MIR4435-2HG downregulation. Mechanistic studies revealed that MIR4435-2HG, a competitive endogenous RNA, directly targeted and inhibited miR-371a-5p. Rescue assays revealed that miR-371a-5p overexpression or SRY-box transcription factor 2 downregulation significantly inhibited MIR4435-2HG-mediated oncogenic effects.

Conclusion

MIR4435-2HG promotes nonsmall cell lung cancer cell malignant behaviors and glycolysis by regulating the miR-371a-5p/SOX2 axis.

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.

Neuroendocrine Differentiation in Prostate Cancer Requires ASCL1

Most patients with prostate adenocarcinoma develop resistance to therapies targeting the androgen receptor (AR). Consequently, a portion of these patients develop AR-independent neuroendocrine (NE) prostate cancer (NEPC), a rapidly progressing cancer with limited therapies and poor survival outcomes. Current research to understand the progression to NEPC suggests a model of lineage plasticity whereby AR-dependent luminal-like tumors progress toward an AR-independent NEPC state. Genetic analysis of human NEPC identified frequent loss of RB1 and TP53, and the loss of both genes in experimental models mediates the transition to a NE lineage. Transcriptomics studies have shown that lineage transcription factors ASCL1 and NEUROD1 are present in NEPC. In this study, we modeled the progression of prostate adenocarcinoma to NEPC by establishing prostate organoids and subsequently generating subcutaneous allograft tumors from genetically engineered mouse models harboring Cre-induced loss of Rb1 and Trp53 with Myc overexpression (RPM). These tumors were heterogeneous and displayed adenocarcinoma, squamous, and NE features. ASCL1 and NEUROD1 were expressed within NE-defined regions, with ASCL1 being predominant. Genetic loss of Ascl1 in this model did not decrease tumor incidence, growth, or metastasis; however, there was a notable decrease in NE identity and an increase in basal-like identity. This study provides an in vivo model to study progression to NEPC and establishes the requirement for ASCL1 in driving NE differentiation in prostate cancer. Significance: Modeling lineage transitions in prostate cancer and testing dependencies of lineage transcription factors have therapeutic implications, given the emergence of treatment-resistant, aggressive forms of neuroendocrine prostate cancer. See related commentary by McQuillen and Brady, p. 3499.

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.

SOX10 mediates glioblastoma cell-state plasticity

Phenotypic plasticity is a cause of glioblastoma therapy failure. We previously showed that suppressing the oligodendrocyte-lineage regulator SOX10 promotes glioblastoma progression. Here, we analyze SOX10-mediated phenotypic plasticity and exploit it for glioblastoma therapy design. We show that low SOX10 expression is linked to neural stem-cell (NSC)-like glioblastoma cell states and is a consequence of temozolomide treatment in animal and cell line models. Single-cell transcriptome profiling of Sox10-KD tumors indicates that Sox10 suppression is sufficient to induce tumor progression to an aggressive NSC/developmental-like phenotype, including a quiescent NSC-like cell population. The quiescent NSC state is induced by temozolomide and Sox10-KD and reduced by Notch pathway inhibition in cell line models. Combination treatment using Notch and HDAC/PI3K inhibitors extends the survival of mice carrying Sox10-KD tumors, validating our experimental therapy approach. In summary, SOX10 suppression mediates glioblastoma progression through NSC/developmental cell-state transition, including the induction of a targetable quiescent NSC state. This work provides a rationale for the design of tumor therapies based on single-cell phenotypic plasticity analysis.

Mechanisms governing lineage plasticity and metabolic reprogramming in cancer

Dynamic alterations in cellular phenotypes during cancer progression are attributed to a phenomenon known as 'lineage plasticity'. This process is associated with therapeutic resistance and involves concurrent shifts in metabolic states that facilitate adaptation to various stressors inherent in malignant growth. Certain metabolites also serve as synthetic reservoirs for chromatin modification, thus linking metabolic states with epigenetic regulation. There remains a critical need to understand the mechanisms that converge on lineage plasticity and metabolic reprogramming to prevent the emergence of lethal disease. This review attempts to offer an overview of our current understanding of the interplay between metabolic reprogramming and lineage plasticity in the context of cancer, highlighting the intersecting drivers of cancer hallmarks, with an emphasis on solid tumors.

Integrated single-cell transcriptomic analyses identify a novel lineage plasticity-related cancer cell type involved in prostate cancer progression

BACKGROUND

Cancer cell plasticity is the ability of neoplastic cells to alter their identity and acquire new biological properties under microenvironmental pressures. In prostate cancer (PCa), lineage plasticity often results in therapy resistance and trans-differentiation to neuroendocrine (NE) lineage. However, identifying the cancer cells harboring lineage plasticity-related status remains challenging.

METHODS

Based on 13 multi-center human PCa bulk transcriptomic cohorts (samples = 3314) and 9 bulk transcriptomic datasets derived from PCa experimental models, we established an integrated lineage plasticity-related gene signature, termed LPSig. Leveraging this gene signature, AUCell enrichment analysis was applied to identify the cell population with high lineage plasticity from a comprehensive single-cell RNA-sequencing (scRNA-seq) meta-atlas assembled by us, which consisted of 10 public human PCa scRNA-seq datasets (samples = 93, cells = 222,529). Moreover, additional scRNA-seq dataset of human PCa, multiplex immunohistochemistry staining for human PCa tissues, in vitro and in vivo functional experiments, as well as qPCR and Western blot analyses were employed to validate our findings.

FINDINGS

We found that LPSig could finely capture the dynamics of tumor lineage plasticity throughout the progression of PCa, accurately estimating the status of lineage plasticity. Based on LPSig, we identified a previously undefined minority population of lineage plasticity-related PCa cells (LPCs) from the human PCa scRNA-seq meta-atlas assembled by this study. Furthermore, in-depth dissection revealed pivotal roles of LPCs in trans-differentiation, tumor recurrence, and poor patient survival during PCa progression. Furthermore, we identified HMMR as a representative cell surface marker for LPCs, which was validated using additional scRNA-seq datasets and multiplexed immunohistochemistry. Moreover, HMMR was transcriptionally inhibited by androgen receptor (AR), and was required for the aggressive adenocarcinoma features and NE phenotype.

INTERPRETATION

Our study uncovers a novel population of lineage plasticity-related cells with low AR activity, stemness-like traits, and elevated HMMR expression, that may facilitate poor prognosis in PCa.

FUNDING

This work was supported by National Key R&D Program of China (2022YFA0807000), National Natural Science Foundation of China (82160584), Advanced Prostate Cancer Diagnosis and Treatment Technology Innovation Team of Kunming Medical University (CXTD202216), and Reserve Talents of Young and Middle-aged Academic Leaders in Yunnan Province (202105AC160013).

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.

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.

Identification of key genes participating in copper-diethyldithiocarbamate-related cell death process and predicting the development of prostate cancer

Copper (Cu) is used as a cofactor in all organisms, and yet it can be toxic at high intracellular concentrations, causing cell death. Diethyldithiocarbamate (DDC) is a Cu ionophore that can transport Cu effectively into the cell. Copper-diethyldithiocarbamate (Cu-DDC) can treat prostate cancer (PCa) and may correlate with the cell death process. However, the specific Cu-DDC-related cell death genes in PCa are still unknown. Information about the Cu-DDC-related cell death genes was obtained from a previous study. Concurrently, the RNA expression profiles and clinical data were downloaded from public databases such as GEO, TCGA, and CPGEA. Using data from TCGA database, the logistic and lasso regression models were generated using R software. The influence of these genes in affecting PCa progression and prognosis was analyzed. Finally, the expression of these genes was verified in clinical samples. We found five Cu-DDC-related cell death genes associated with the occurrence of PCa from GSE35988, a gene dataset, namely, CDKN2A, PRC1, CDK1, SOX2, and ZNF365. CDKN2A, PRC1, and CDK1 are known to influence PCa patients' disease-free survival (DFS) status and were overexpressed, whereas SOX2 and ZNF365 were under-expressed in PCa in the different databases. Some of these genes can affect PCa progression. Consistent with the database results, the mRNA and protein expression of CDKN2A, PRC1, and CDK1 was also higher in clinical samples. In conclusion, we identified five hub genes which are important for Cu-DDC-related cell death process that can predict the development of PCa.

TRIB3 inhibition by palbociclib sensitizes prostate cancer to ferroptosis via downregulating SOX2/SLC7A11 expression

Palbociclib is a CDK4/6 inhibitor approved for the treatment of breast cancer by suppressing cell proliferation. However, monotherapy with palbociclib was discouraging in prostate cancer, calling for a mechanism-based effective therapy. In this study, we reported in prostate cancer that palbociclib is a potent sensitizer of ferroptosis, which is worked out by downregulating the expression of TRIB3, a gene highly expressed in prostate cancer. Specifically, TRIB3 knockdown augmented the response of prostate cancer cells to ferroptosis inducers, whereas, TRIB3 overexpression rescued prostate cancer cells from palbociclib-induced ferroptosis. Mechanistically, TRIB3 inhibition by palbociclib resulted in downregulation of SOX2, which subsequently led to compromised expression of SLC7A11, a cystine/glutamate antiporter that counteracts ferroptosis. Functionally, a combined treatment of palbociclib with ferroptosis inducer significantly suppressed prostate cancer growth in a xenograft tumor model. Together, these results uncover an essential role of TRIB3/SOX2/SLC7A11 axis in palbociclib-induced ferroptosis, suggesting palbociclib a promising targeted therapy in combine with ferroptosis induction for the treatment of 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.

Small cell lung cancer profiling: an updated synthesis of subtypes, vulnerabilities, and plasticity

Small cell lung cancer (SCLC) is a devastating disease with high proliferative and metastatic capacity. SCLC has been classified into molecular subtypes based on differential expression of lineage-defining transcription factors. Recent studies have proposed new subtypes that are based on both tumor-intrinsic and -extrinsic factors. SCLC demonstrates substantial intratumoral subtype heterogeneity characterized by highly plastic transcriptional states, indicating that the initially dominant subtype can shift during disease progression and in association with resistance to therapy. Strategies to promote or constrain plasticity and cell fate transitions have nominated novel targets that could prompt the development of more durably effective therapies for patients with SCLC. In this review, we describe the latest advances in SCLC subtype classification and their biological and clinical implications.

Wnt-deficient and hypoxic environment orchestrates squamous reprogramming of human pancreatic ductal adenocarcinoma

Human pancreatic cancer is characterized by the molecular diversity encompassing native duct-like and squamous cell-like identities, but mechanisms underlying squamous transdifferentiation have remained elusive. To comprehensively capture the molecular diversity of human pancreatic cancer, we here profiled 65 patient-derived pancreatic cancer organoid lines, including six adenosquamous carcinoma lines. H3K27me3-mediated erasure of the ductal lineage specifiers and hijacking of the TP63-driven squamous-cell programme drove squamous-cell commitment, providing survival benefit in a Wnt-deficient environment and hypoxic conditions. Gene engineering of normal pancreatic duct organoids revealed that GATA6 loss and a Wnt-deficient environment, in concert with genetic or hypoxia-mediated inactivation of KDM6A, facilitate squamous reprogramming, which in turn enhances environmental fitness. EZH2 inhibition counterbalanced the epigenetic bias and curbed the growth of adenosquamous cancer organoids. Our results demonstrate how an adversarial microenvironment dictates the molecular and histological evolution of human pancreatic cancer and provide insights into the principles and significance of lineage conversion in human cancer.

Prostate Cancer: A Review of Genetics, Current Biomarkers and Personalised Treatments

BACKGROUND

Prostate cancer is the second leading cause of cancer deaths in men, second only to lung cancer. Despite this, diagnosis and prognosis methods remain limited, with effective treatments being few and far between. Traditionally, prostate cancer is initially tested for through a prostate serum antigen (PSA) test and a digital rectum examination (DRE), followed by confirmation through an invasive prostate biopsy. The DRE and biopsy are uncomfortable for the patient, so less invasive, accurate diagnostic tools are needed. Current diagnostic tools, along with genes that hold possible biomarker uses in diagnosis, prognosis and indications for personalised treatment plans, were reviewed in this article.

RECENT FINDINGS

Several genes from multiple families have been identified as possible biomarkers for disease, including those from the MYC and ETS families, as well as several tumour suppressor genes, Androgen Receptor signalling genes and DNA repair genes. There have also been advances in diagnostic tools, including MRI-targeted and liquid biopsies. Several personalised treatments have been developed over the years, including those that target metabolism-driven prostate cancer or those that target inflammation-driven cancer.

CONCLUSION

Several advances have been made in prostate cancer diagnosis and treatment, but the disease still grows year by year, leading to more and more deaths annually. This calls for even more research into this disease, allowing for better diagnosis and treatment methods and a better chance of patient survival.

Integrated multi-omics assessment of lineage plasticity in a prostate cancer patient with brain and dural metastases

Metastases to the brain are rare in prostate cancer. Here, we describe a patient with two treatment-emergent metastatic lesions, one to the brain with neuroendocrine prostate cancer (NEPC) histology and one to the dural membrane of adenocarcinoma histology. We performed genomic, transcriptomic, and proteomic characterization of these lesions and the primary tumor to investigate molecular features promoting these metastases. The two metastatic lesions had high genomic similarity, including TP53 mutation and PTEN deletion, with the most striking difference being the additional loss of RB1 in the NEPC lesion. Interestingly, the dural lesion expressed both androgen receptor and neuroendocrine markers, suggesting amphicrine carcinoma (AMPC). When analyzing pioneer transcription factors, the AMPC lesion exhibited elevated FOXA1 activity while the brain NEPC lesion showed elevated HOXC10, NFYB, and OTX2 expression suggesting novel roles in NEPC formation or brain tropism. Our results highlight the utility of performing multi-omic characterization, especially in rare cancer subtypes.

Enhanced desmosome assembly driven by acquired high-level desmoglein-2 promotes phenotypic plasticity and endocrine resistance in ER+ breast cancer

Acquired resistance to endocrine treatments remains a major clinical challenge. In this study, we found that desmoglein-2 (DSG2) plays a major role in acquired endocrine resistance and cellular plasticity in ER+ breast cancer (BC). By analysing the well-established fulvestrant-resistant ER+ BC model using single-cell RNA-seq, we revealed that ER inhibition leads to a specific increase in DSG2 in cancer cell populations, which in turn enhances desmosome formation in vitro and in vivo and cell phenotypic plasticity that promotes resistance to treatment. DSG2 depletion reduced tumorigenesis and metastasis in fulvestrant-resistant xenograft models and promoted fulvestrant efficiency. Mechanistically, DSG2 forms a desmosome complex with JUP and Vimentin and triggers Wnt/PCP signalling. We showed that elevated DSG2 levels, along with reduced ER levels and an activated Wnt/PCP pathway, predicted poor survival, suggesting that a DSG2high signature could be exploited for therapeutic interventions. Our analysis highlighted the critical role of DSG2-mediated desmosomal junctions following antiestrogen treatment.

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.

Evidence of the Link between Stroma Remodeling and Prostate Cancer Prognosis

Prostate cancer (PCa), the most commonly diagnosed cancer in men worldwide, is particularly challenging for oncologists when a precise prognosis needs to be established. Indeed, the entire clinical management in PCa has important drawbacks, generating an intense debate concerning the possibility to individuate molecular biomarkers able to avoid overtreatment in patients with pathological indolent cancers. To date, the paradigmatic change in the view of cancer pathogenesis prompts to look for prognostic biomarkers not only in cancer epithelial cells but also in the tumor microenvironment. PCa ecology has been defined with increasing details in the last few years, and a number of promising key markers associated with the reactive stroma are now available. Here, we provide an updated description of the most biologically significant and cited prognosis-oriented microenvironment biomarkers derived from the main reactive processes during PCa pathogenesis: tissue adaptations, inflammatory response and metabolic reprogramming. Proposed biomarkers include factors involved in stromal cell differentiation, cancer-normal cell crosstalk, angiogenesis, extracellular matrix remodeling and energy metabolism.

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.

BCL2 expression is enriched in advanced prostate cancer with features of lineage plasticity

The widespread use of potent androgen receptor signaling inhibitors (ARSIs) has led to an increasing emergence of AR-independent castration-resistant prostate cancer (CRPC), typically driven by loss of AR expression, lineage plasticity, and transformation to prostate cancers (PCs) that exhibit phenotypes of neuroendocrine or basal-like cells. The anti-apoptotic protein BCL2 is upregulated in neuroendocrine cancers and may be a therapeutic target for this aggressive PC disease subset. There is an unmet clinical need, therefore, to clinically characterize BCL2 expression in metastatic CRPC (mCRPC), determine its association with AR expression, uncover its mechanisms of regulation, and evaluate BCL2 as a therapeutic target and/or biomarker with clinical utility. Here, using multiple PC biopsy cohorts and models, we demonstrate that BCL2 expression is enriched in AR-negative mCRPC, associating with shorter overall survival and resistance to ARSIs. Moreover, high BCL2 expression associates with lineage plasticity features and neuroendocrine marker positivity. We provide evidence that BCL2 expression is regulated by DNA methylation, associated with epithelial-mesenchymal transition, and increased by the neuronal transcription factor ASCL1. Finally, BCL2 inhibition had antitumor activity in some, but not all, BCL2-positive PC models, highlighting the need for combination strategies to enhance tumor cell apoptosis and enrich response.

Human intermediate prostate cancer stem cells contribute to the initiation and development of prostate adenocarcinoma

BACKGROUND

Intermediate cells are present in the early stages of human prostate development and adenocarcinoma. While primary cells isolated from benign human prostate tissues or tumors exhibit an intermediate phenotype in vitro, they cannot form tumors in vivo unless genetically modified. It is unclear about the stem cell properties and tumorigenicity of intermediate cells.

METHODS

We developed a customized medium to culture primary human intermediate prostate cells, which were transplanted into male immunodeficient NCG mice to examine tumorigenicity in vivo. We treated the cells with different concentrations of dihydrotestosterone (DHT) and enzalutamide in vitro and surgically castrated the mice after cell transplantation in vivo. Immunostaining, qRT-PCR, RNA sequencing, and western blotting were performed to characterize the cells in tissues and 2D and 3D cultures.

RESULTS

We found intermediate cells expressing AR+PSA+CK8+CK5+ in the luminal compartment of human prostate adenocarcinoma by immunostaining. We cultured the primary intermediate cells in vitro, which expressed luminal (AR+PSA+CK8+CK18+), basal (CK5+P63+), intermediate (IVL+), and stem cell (CK4+CK13+PSCA+SOX2+) markers. These cells resisted castration in vitro by upregulating the expression of AR, PSA, and proliferation markers KI67 and PCNA. The intermediate cells had high tumorigenicity in vivo, forming tumors in immunodeficient NCG mice in a month without any genetic modification or co-transplantation with embryonic urogenital sinus mesenchyme (UGSM) cells. We named these cells human castration-resistant intermediate prostate cancer stem cells or CriPCSCs and defined the xenograft model as patient primary cell-derived xenograft (PrDX). Human CriPCSCs resisted castration in vitro and in vivo by upregulating AR expression. Furthermore, human CriPCSCs differentiated into amplifying adenocarcinoma cells of luminal phenotype in PrDX tumors in vivo, which can dedifferentiate into CriPCSCs in vitro.

CONCLUSIONS

Our study identified and established methods for culturing human CriPCSCs, which had high tumorigenicity in vivo without any genetic modification or UGSM co-transplantation. Human CriPCSCs differentiated into amplifying adenocarcinoma cells of luminal phenotype in the fast-growing tumors in vivo, which hold the potential to dedifferentiate into intermediate stem cells. These cells resisted castration by upregulating AR expression. The human CriPCSC and PrDX methods hold significant potential for advancing prostate cancer research and precision medicine.

Castration-resistant prostate cancer monitoring by cell-free circulating biomarkers

Background

Prostate cancer is the second leading cause of male cancer-related deaths in Western countries, which is predominantly attributed to the metastatic castration-resistant stage of the disease (CRPC). There is an urgent need for better prognostic and predictive biomarkers, particularly for androgen receptor targeted agents and taxanes.

Methods

We have searched the PubMed database for original articles and meta-analyses providing information on blood-based markers for castration-resistant prostate cancer monitoring, risk group stratification and prediction of therapy response.

Results

The molecular markers are discussed along with the standard clinical parameters, such as prostate specific antigen, lactate dehydrogenase or C-reactive protein. Androgen receptor (AR) alterations are commonly associated with progression to CRPC. These include amplification of AR and its enhancer, point mutations and splice variants. Among DNA methylations, a novel 5-hydroxymethylcytosine activation marker of TOP2A and EZH2 has been identified for the aggressive disease. miR-375 is currently the most promising candidate among non-coding RNAs and sphingolipid analysis has recently emerged as a novel approach.

Conclusions

The promising biomarkers have the potential to improve the care of metastatic prostate cancer patients, however, they need further validation for routine implementation.

Cancer plasticity in therapy resistance: Mechanisms and novel strategies

Therapy resistance poses a significant obstacle to effective cancer treatment. Recent insights into cell plasticity as a new paradigm for understanding resistance to treatment: as cancer progresses, cancer cells experience phenotypic and molecular alterations, corporately known as cell plasticity. These alterations are caused by microenvironment factors, stochastic genetic and epigenetic changes, and/or selective pressure engendered by treatment, resulting in tumor heterogeneity and therapy resistance. Increasing evidence suggests that cancer cells display remarkable intrinsic plasticity and reversibly adapt to dynamic microenvironment conditions. Dynamic interactions between cell states and with the surrounding microenvironment form a flexible tumor ecosystem, which is able to quickly adapt to external pressure, especially treatment. Here, this review delineates the formation of cancer cell plasticity (CCP) as well as its manipulation of cancer escape from treatment. Furthermore, the intrinsic and extrinsic mechanisms driving CCP that promote the development of therapy resistance is summarized. Novel treatment strategies, e.g., inhibiting or reversing CCP is also proposed. Moreover, the review discusses the multiple lines of ongoing clinical trials globally aimed at ameliorating therapy resistance. Such advances provide directions for the development of new treatment modalities and combination therapies against CCP in the context of therapy resistance.

Mechanisms of resistance to tyrosine kinase inhibitor-targeted therapy and overcoming strategies

Tyrosine kinase inhibitor (TKI)-targeted therapy has revolutionized cancer treatment by selectively blocking specific signaling pathways crucial for tumor growth, offering improved outcomes with fewer side effects compared with conventional chemotherapy. However, despite their initial effectiveness, resistance to TKIs remains a significant challenge in clinical practice. Understanding the mechanisms underlying TKI resistance is paramount for improving patient outcomes and developing more effective treatment strategies. In this review, we explored various mechanisms contributing to TKI resistance, including on-target mechanisms and off-target mechanisms, as well as changes in the tumor histology and tumor microenvironment (intrinsic mechanisms). Additionally, we summarized current therapeutic approaches aiming at circumventing TKI resistance, including the development of next-generation TKIs and combination therapies. We also discussed emerging strategies such as the use of dual-targeted antibodies and PROteolysis Targeting Chimeras. Furthermore, we explored future directions in TKI-targeted therapy, including the methods for detecting and monitoring drug resistance during treatment, identification of novel targets, exploration of dual-acting kinase inhibitors, application of nanotechnologies in targeted therapy, and so on. Overall, this review provides a comprehensive overview of the challenges and opportunities in TKI-targeted therapy, aiming to advance our understanding of resistance mechanisms and guide the development of more effective therapeutic approaches in cancer treatment.

Single-cell analysis revealing the metabolic landscape of prostate cancer

ABSTRACT

Tumor metabolic reprogramming is a hallmark of cancer development, and targeting metabolic vulnerabilities has been proven to be an effective approach for castration-resistant prostate cancer (CRPC) treatment. Nevertheless, treatment failure inevitably occurs, largely due to cellular heterogeneity, which cannot be deciphered by traditional bulk sequencing techniques. By employing computational pipelines for single-cell RNA sequencing, we demonstrated that epithelial cells within the prostate are more metabolically active and plastic than stromal cells. Moreover, we identified that neuroendocrine (NE) cells tend to have high metabolic rates, which might explain the high demand for nutrients and energy exhibited by neuroendocrine prostate cancer (NEPC), one of the most lethal variants of prostate cancer (PCa). Additionally, we demonstrated through computational and experimental approaches that variation in mitochondrial activity is the greatest contributor to metabolic heterogeneity among both tumor cells and nontumor cells. These results establish a detailed metabolic landscape of PCa, highlight a potential mechanism of disease progression, and emphasize the importance of future studies on tumor heterogeneity and the tumor microenvironment from a metabolic perspective.