Epithelial-Mesenchymal Transition Signaling and Prostate Cancer Stem Cells: Emerging Biomarkers and Opportunities for Precision Therapeutics

CD133-targeted multifunctional nanomicelles for dual-modality imaging and synergistic high-intensity focus ultrasound (HIFU) ablation on pancreatic cancer in nude mice

Pancreatic cancer is an aggressive and highly fatal malignant tumor. Recent studies have shown that cancer stem cells (CSCs) play an important role in resisting current therapeutic modalities. Furthermore, CD133 is highly expressed in CSCs. High-intensity focused ultrasound (HIFU) is a promising non-invasive therapeutic strategy for unresectable pancreatic cancers. In our study, we synthesized targeted CD133 organosilane nanomicelles by encapsulating perfluorohexane (PFH). The CD133 antibody on the surface could specifically bind to CD133-positive pancreatic cancer cells and selectively concentrate in pancreatic cancer tumor tissues. PFH was introduced to improve the ablation effect of HIFU due to its liquid-gas phase transition properties. By combining with the dorsal skinfold window chamber model (DSWC) of pancreatic cancer in nude mice, multiphoton fluorescence microscopy was used to evaluate the targeting effect of nanomicelles on pancreatic cancer tumor tissue. These multifunctional nanomicelles synergistically affected HIFU treatment of pancreatic cancer, providing an integrated research platform for diagnosing and treating pancreatic cancer with HIFU.

Differences in Tumor Gene Expression Profiles Between De Novo Metastatic Castration-sensitive Prostate Cancer and Metastatic Relapse After Prior Localized Therapy

BACKGROUND AND OBJECTIVE

It has been reported that patients with de novo metastatic castration-sensitive prostate cancer (dn-mCSPC) have worse prognosis and outcomes than those whose cancer relapses after prior local therapy (PLT-mCSPC). Our aim was to interrogate and validate underlying differences in tumor gene expression profiles between dn-mCSPC and PLT-mCSPC.

METHODS

The inclusion criteria were histologically confirmed prostate adenocarcinoma and the availability of RNA sequencing data for treatment-naïve primary prostate tissue. RNA sequencing was performed by Tempus or Caris Life Sciences, both of which have Clinical Laboratory Improvement Amendments certification. The Tempus cohort was used for interrogation, while the Caris cohort was used for validation. Differential gene expression analysis between the cohorts was conducted using the DEseq2 pipeline. The resulting gene expression profiles were further analyzed using Gene Set Enrichment software to identify pathways with enrichment in each cohort.

KEY FINDINGS AND LIMITATIONS

Overall, 128 patients were eligible, of whom 78 were in the Tempus cohort (dn-mCSPC 37, PLT-mCSPC 41) and 50 were in the Caris cohort (dn-mCSPC 30, PLT-mCSPC 20). Tumor tissues from patients with dn-mCSPC had higher expression of genes associated with inflammation pathways, while tissues from patients with PLT-mCSPC had higher expression of genes involved in oxidative phosphorylation, fatty acid metabolism, and androgen response pathways.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Our study revealed upregulation of distinct genomic pathways in dn-mCSPC in comparison to PLT-mCSPC. These hypothesis-generating data could guide personalized therapy for men with prostate cancer and explain different survival outcomes for dn-mCSPC and PLT-mCSPC.

PATIENT SUMMARY

We measured gene expression levels in tumors from patients with metastatic castration-sensitive prostate cancer. In patients with metastatic disease at first diagnosis, inflammatory pathways were upregulated. In patients whose metastasis occurred on relapse after treatment, androgen response pathways were upregulated. These findings could help in personalizing therapy for prostate cancer and explaining differences in survival.

Epithelial-mesenchymal transition dysregulation in prostate cancer: Insights from molecular unraveling and epidemiological analyses in Tunisia, North Africa

INTRODUCTION

The progression of prostate cancer (PCa) has been linked worldwide, including in African populations, to the dysregulation of the epithelial-mesenchymal transition (EMT).

METHODS

To clarify the connection among EMT markers, clinicopathological parameters, and epidemiological factors, we analyzed 35 PCa specimens from patients in Tunisia, a country in North Africa, arranged by stages. We also carried out extensive molecular and epidemiological analyses.

RESULTS

Significant dysregulation of EMT genes was found, with an overexpression of ZEB-1, Twist, Snail-1, and Vimentin (p < 0.05) and underexpression of E-cadherin and β-catenin (p < 0.05). Positive correlations were observed between transcription factors and the mesenchymal marker Vimentin (p < 0.001, r = 0.574; p = 0.029, r = 0.411; and p < 0.001; r = 0.506) according to Spearman correlation analyses, whereas negative correlations were found between epithelial markers (E-cadherin, β-catenin) and Vimentin (p < 0.05; r < 0). Higher PSA, Gleason scores, and metastasis were all correlated with the dysregulation of EMT (p < 0.05). Notably, there was a positive correlation between higher consumption of tobacco (≥20 Packets per year) and Vimentin expression (p < 0.001, r = 0.854), suggesting a relationship between smoking and EMT activation in the Tunisian population. Moreover, Twist showed a positive correlation with diabetes (p < 0.001, r = 0.385), whereas no significant correlations were found between EMT markers and comorbidities such as hypertension and coronary insufficiency. These results demonstrate the intricate connection between molecular changes, epidemiological factors, and disease progression, and they emphasize the crucial role that EMT plays in promoting PCa aggressiveness in African populations, particularly in Tunisia.

CONCLUSION

In summary, understanding these correlations could help develop focused treatment plans and enhance patient outcomes for PCa management in African settings.

PRMT6-mediated transcriptional activation of ythdf2 promotes glioblastoma migration, invasion, and emt via the wnt-β-catenin pathway

BACKGROUND

Protein arginine methyltransferase 6 (PRMT6) plays a crucial role in various pathophysiological processes and diseases. Glioblastoma (GBM; WHO Grade 4 glioma) is the most common and lethal primary brain tumor in adults, with a prognosis that is extremely poor, despite being less common than other systemic malignancies. Our current research finds PRMT6 upregulated in GBM, enhancing tumor malignancy. Yet, the specifics of PRMT6's regulatory processes and potential molecular mechanisms in GBM remain largely unexplored.

METHODS

PRMT6's expression and prognostic significance in GBM were assessed using glioma public databases, immunohistochemistry (IHC), and immunoblotting. Scratch and Transwell assays examined GBM cell migration and invasion. Immunoblotting evaluated the expression of epithelial-mesenchymal transition (EMT) and Wnt-β-catenin pathway-related proteins. Dual-luciferase reporter assays and ChIP-qPCR assessed the regulatory relationship between PRMT6 and YTHDF2. An in situ tumor model in nude mice evaluated in vivo conditions.

RESULTS

Bioinformatics analysis indicates high expression of PRMT6 and YTHDF2 in GBM, correlating with poor prognosis. Functional experiments show PRMT6 and YTHDF2 promote GBM migration, invasion, and EMT. Mechanistic experiments reveal PRMT6 and CDK9 co-regulate YTHDF2 expression. YTHDF2 binds and promotes the degradation of negative regulators APC and GSK3β mRNA of the Wnt-β-catenin pathway, activating it and consequently enhancing GBM malignancy.

CONCLUSIONS

Our results demonstrate the PRMT6-YTHDF2-Wnt-β-Catenin axis promotes GBM migration, invasion, and EMT in vitro and in vivo, potentially serving as a therapeutic target for GBM.

Investigating the Role of SNAI1 and ZEB1 Expression in Prostate Cancer Progression and Immune Modulation of the Tumor Microenvironment

Prostate cancer (PCa) is an immunologically cold tumor and the molecular processes that underlie this behavior are poorly understood. In this study, we investigated a primary cohort of intermediate-risk PCa (n = 51) using two NanoString profiling panels designed to study cancer progression and immune response. We identified differentially expressed genes (DEGs) and pathways associated with biochemical recurrence (BCR) and clinical risk. Confirmatory analysis was performed using the TCGA-PRAD cohort. Noteworthy DEGs included collagens such as COL1A1, COL1A2, and COL3A1. Changes in the distribution of collagens may influence the immune activity in the tumor microenvironment (TME). In addition, immune-related DEGs such as THY1, IRF5, and HLA-DRA were also identified. Enrichment analysis highlighted pathways such as those associated with angiogenesis, TGF-beta, UV response, and EMT. Among the 39 significant DEGs, 11 (28%) were identified as EMT target genes for ZEB1 using the Harmonizome database. Elevated ZEB1 expression correlated with reduced BCR risk. Immune landscape analysis revealed that ZEB1 was associated with increased immunosuppressive cell types in the TME, such as naïve B cells and M2 macrophages. Increased expression of both ZEB1 and SNAI1 was associated with elevated immune checkpoint expression. In the future, modulation of EMT could be beneficial for overcoming immunotherapy resistance in a cold tumor, such as PCa.

Nuclear receptor NURR1 functions to promote stemness and epithelial-mesenchymal transition in prostate cancer via its targeting of Wnt/β-catenin signaling pathway

Dysregulated activation of Wnt/β-catenin signaling pathway is a frequent or common event during advanced progression of multiple cancers. With this signaling activation, it enhances their tumorigenic growth and facilitates metastasis and therapy resistance. Advances show that this signaling pathway can play dual regulatory roles in the control of cellular processes epithelial-mesenchymal transition (EMT) and cancer stemness in cancer progression. Aberrant activation of Wnt/β-catenin signaling pathway is shown to be common in prostate cancer and also castration-resistant prostate cancer (CRPC). However, the transcriptional regulators of this pathway in prostate cancer are still not well characterized. NURR1 (NR4A2) is an orphan nuclear receptor and plays an important role in the development of dopaminergic neurons. Previously, we have shown that NURR1 exhibits an upregulation in isolated prostate cancer stem-like cells (PCSCs) and a xenograft model of CRPC. In this study, we further confirmed that NURR1 exhibited an upregulation in prostate cancer and also enhanced expression in prostate cancer cell lines. Functional and molecular analyses showed that NURR1 could act to promote both in vitro (cancer stemness and EMT) and also in vivo oncogenic growth of prostate cancer cells (metastasis and castration resistance) via its direct transactivation of CTNNB1 (β-catenin) and activation of β-catenin to mediate the activation of Wnt/β-catenin signaling pathway. Moreover, we also demonstrated that NURR1 activity in prostate cancer cells could be modulated by small molecules, implicating that NURR1 could be a potential therapeutic target for advanced prostate cancer management.

Biomolecular fingerprints of the effect of zoledronic acid on prostate cancer stem cells: Comparison of 2D and 3D cell culture models

Revealing the potential of candidate drugs against different cancer types without disrupting normal cells depends on the drug mode of action. In the current study, the drug response of prostate cancer stem cells (PCSCs) to zoledronic acid (ZOL) grown in two-dimensional (2D) and three-dimensional (3D) culture systems was compared using Fourier transform-infrared (FT-IR) spectroscopy which is a vibrational spectroscopic technique, supporting by biochemical assays and imaging techniques. Based on our data, in 2D cell culture conditions, the ZOL treatment of PCSCs isolated according to both C133 and CD44 cell surface properties induced early/late apoptosis and suppressed migration ability. The CD133 gene expression and protein levels were altered, depending on culture systems. CD133 expression was significantly reduced in 2D cells upon ZOL treatment. FT-IR data revealed that the integrity, fluidity, and ordering/disordering states of the cell membrane and nucleic acid content were altered in both 2D and 3D cells after ZOL treatment. Regular protein structures decrease in 2D cells while glycogen and protein contents increase in 3D cells, indicating a more pronounced cytotoxic effect of ZOL for 2D cells. Untreated 3D PCSCs exhibited an even different spectral profile associated with IR signals of lipids, proteins, nucleic acids, and glycogen in comparison to untreated 2D cells. Our study revealed significant differences in the drug response and cellular constituents between 2D and 3D cells. Exploring molecular targets and/or drug-action mechanisms is significant in cancer treatment approaches; thus, FT-IR spectroscopy can be successfully applied as a novel drug-screening method in clinical research.

Epithelial-Mesenchymal Transition: A Fundamental Cellular and Microenvironmental Process in Benign and Malignant Prostate Pathologies

Epithelial-mesenchymal transition (EMT) is a crucial and fundamental mechanism in many cellular processes, beginning with embryogenesis via tissue remodulation and wound healing, and plays a vital role in tumorigenesis and metastasis formation. EMT is a complex process that involves many transcription factors and genes that enable the tumor cell to leave the primary location, invade the basement membrane, and send metastasis to other tissues. Moreover, it may help the tumor avoid the immune system and establish radioresistance and chemoresistance. It may also change the normal microenvironment, thus promoting other key factors for tumor survival, such as hypoxia-induced factor-1 (HIF-1) and promoting neoangiogenesis. In this review, we will focus mainly on the role of EMT in benign prostate disease and especially in the process of establishment of malignant prostate tumors, their invasiveness, and aggressive behavior. We will discuss relevant study methods for EMT evaluation and possible clinical implications. We will also introduce clinical trials conducted according to CONSORT 2010 that try to harness EMT properties in the form of circulating tumor cells to predict aggressive patterns of prostate cancer. This review will provide the most up-to-date information to establish a keen understanding of the cellular and microenvironmental processes for developing novel treatment lines by modifying or blocking the pathways.

Transcending frontiers in prostate cancer: the role of oncometabolites on epigenetic regulation, CSCs, and tumor microenvironment to identify new therapeutic strategies

Prostate cancer, as one of the most prevalent malignancies in males, exhibits an approximate 5-year survival rate of 95% in advanced stages. A myriad of molecular events and mutations, including the accumulation of oncometabolites, underpin the genesis and progression of this cancer type. Despite growing research demonstrating the pivotal role of oncometabolites in supporting various cancers, including prostate cancer, the root causes of their accumulation, especially in the absence of enzymatic mutations, remain elusive. Consequently, identifying a tangible therapeutic target poses a formidable challenge. In this review, we aim to delve deeper into the implications of oncometabolite accumulation in prostate cancer. We center our focus on the consequential epigenetic alterations and impacts on cancer stem cells, with the ultimate goal of outlining novel therapeutic strategies.

Tumor protein D52 (isoform 3) induces NF-κB - STAT3 mediated EMT driving neuroendocrine differentiation of prostate cancer cells

In prostate cancer (PCa) patients, a proto-oncogene Tumor protein D52 (TPD52) is overexpressed, and it is involved in different cellular functions. In this study, we report that TPD52 expression is positively associated with the emergence of neuroendocrine PCa (NEPC). With overexpression of TPD52 in LNCaP cells, we found neuroendocrine differentiation (NED) of cells in in-vitro and distinct NED features confirmed by NE markers neuron-specific enolase (NSE) and chromogranin A (CHR-A). Further, we investigated the molecular mechanisms involved in TPD52 mediated NED of PCa cells. We found that TPD52 activates the NF- κB - STAT3 axis for the induction of NED in LNCaP cells. Indeed, inhibition of NF-κB - STAT3 attenuated the progression of NED in TPD52 positive LNCaP cells. Importantly, silencing of TPD52 expression or inhibition of NF-κB - STAT3 activity in a neuroendocrine cell line NCI-H660 showed a marked decrease in the expression of NSE and CHR-A, confirming the reversal of the NE properties. Notably, TPD52 overexpression in LNCaP cells induced expression of N-cadherin, Vimentin, ZEB1, and Snail1 indicating that TPD52 positively regulates epithelial to mesenchymal transition (EMT) of PCa cells towards NED. Moreover, silencing of Snail1 in TPD52 positive cells blocked the progression of NED and, in NCI-H660 cells reversed NE properties as expected. Of the few requirements of TPD52, activation of NF-κB - STAT3 is essential for promoting EMT compelling NED of LNCaP cells. Collectively, these results reveal that TPD52 is associated with the progression of NEPC and emphasizes the need for therapeutic targeting of TPD52 in PCa.

FOXS1 promotes prostate cancer progression through the Hedgehog/Gli1 pathway

BACKGROUND

Prostate cancer (PCa) remains the most common malignant tumor in men, and the clinical treatment still faces many challenges. Several molecular biomarkers of PCa progression have been reported, however, whether FOXS1 can serve as a new biomarker in PCa remains unknown.

METHODS

FOXS1 and Gli1 expression was assessed by RT-qPCR and western blot. The binding and regulation roles between FOXS1 and Gli1 were confirmed by Co-IP and ubiquitination assays. Cell viability, proliferation, apoptosis, migration, invasion and EMT progress were assessed through CCK-8, colony formation, flow cytometry, wound-healing, transwell and western blot assays, respectively. In vivo nude mice tumorigenesis model was also conducted to verify PCa growth.

RESULTS

FOXS1 was upregulated in the PCa TCGA dataset and cells. High FOXS1 level was correlated with PCa patients' worse tumor stage and shorter survival. FOXS1 knockdown inhibited PCa cell proliferation, invasion, migration, EMT and tumor growth while increased cell apoptosis. Furthermore, FOXS1 knockdown decreased the inactivation of Hedgehog (Hh) pathway. FOXS1 bind to Gli1 and decreased the ubiquitination of Gli1, which resulted in the upregulation of Gli1. Besides, both Gil1 overexpression and Hh signal activation reversed the suppression function of FOXS1 silencing on PCa growth and metastasis.

CONCLUSION

FOXS1 bind and stabilized Gli1 by blocking Gli1 ubiquitination, thereby activating Hh signaling to promote PCa cell growth and metastasis.

Periprostatic adipose tissue thromboinflammation triggers prostatic neoplasia in early metabolic impairment: Interruption by rivaroxaban

AIMS

Prostate cancer is among the highest incidence malignancies in men with a prevalence rate increasing in parallel to the rising global trends in metabolic disorders. Whereas a sizeable body of evidence links metabolic impairment to negative prognosis of prostate cancer, the molecular mechanism underlying this connection has not been thoroughly examined. Our previous work showed that localized adipose tissue inflammation occurring in select adipose depots in early metabolic derangement instigated significant molecular, structural, and functional alterations in neighboring tissues underlying the complications observed at this stage. In this context, the periprostatic adipose tissue (PPAT) constitutes an understudied microenvironment with potential influence on the prostatic milieu.

MAIN METHODS AND RESULTS

We show that PPAT inflammation occurs in early prediabetes with signs of increased thrombogenic activity including enhanced expression and function of Factor X. This was mirrored by early neoplastic alterations in the prostate with fibrosis, increased epithelial thickness with marked luminal cellular proliferation and enhanced formation of intraepithelial neoplasia. Significantly, interruption of the procoagulant state in PPAT by a 10-day anticoagulant rivaroxaban treatment not only mitigated PPAT inflammation, but also reduced signs of prostatic neoplastic changes. Moreover, rivaroxaban decreased the murine PLum-AD epithelial prostatic cell viability, proliferation, migration, and colony forming capacity, while increasing oxidative stress. A protease-activated receptor-2 agonist reversed some of these effects.

SIGNIFICANCE

We provide some evidence of a molecular framework for the crosstalk between PPAT and prostatic tissue leading to early neoplastic changes in metabolic impairment mediated by upregulation of PPAT thromboinflammation.

Mechanistic Insights on Localized to Metastatic Prostate Cancer Transition and Therapeutic Opportunities

Prostate cancer is the most common non-cutaneous cancer among American men. Multiple mechanisms are involved in tumorigenesis and progression to metastases. While androgen deprivation therapy remains the cornerstone of treatment, progression to castration-resistant disease becomes inevitable. Aberrant pathway activations of PI3K/AKT due to PTEN loss, epithelial-mesenchymal transition pathways, homologous recombination repair, and DNA repair pathway mechanisms of resistance and cross-talk lead to opportunities for therapeutic targeting in metastatic castration-resistant prostate cancer. This review focuses on mechanisms of progression and key trials that evaluate the drugs and combinations that exploit these pathways.

Exploring the promising potential of induced pluripotent stem cells in cancer research and therapy

The advent of iPSCs has brought about a significant transformation in stem cell research, opening up promising avenues for advancing cancer treatment. The formation of cancer is a multifaceted process influenced by genetic, epigenetic, and environmental factors. iPSCs offer a distinctive platform for investigating the origin of cancer, paving the way for novel approaches to cancer treatment, drug testing, and tailored medical interventions. This review article will provide an overview of the science behind iPSCs, the current limitations and challenges in iPSC-based cancer therapy, the ethical and social implications, and the comparative analysis with other stem cell types for cancer treatment. The article will also discuss the applications of iPSCs in tumorigenesis, the future of iPSCs in tumorigenesis research, and highlight successful case studies utilizing iPSCs in tumorigenesis research. The conclusion will summarize the advancements made in iPSC-based tumorigenesis research and the importance of continued investment in iPSC research to unlock the full potential of these cells.

RCC2 promotes prostate cancer cell proliferation and migration through Hh/GLI1 signaling pathway and cancer stem-like cells

BACKGROUND

Regulator of chromosome condensation 2 (RCC2) was a telophase disk-binding protein on mitosis, and functions as an oncogene in many human cancers. However, its role on prostate cancer (PCa) was unknown. The goal of this study is to explore the function of RCC 2 on PCa development.

METHODS

The expression of RCC2 and its methylation level, its correlation with lymph node metastasis or disease-free survival (DFS) was analyzed using TCGA database. The effect of RCC2 on PCa cell proliferation, migration and invasion were detected using CCK-8, cell colony formation, Transwell and wood healing assays. RNA-seq and GSEA analysis were used to search the downstream genes and pathways of RCC2 in mediated PCa progression. Western blot was used to detect the proteins in PCa cells transfected with indicated siRNAs or plasmids.

RESULTS

RCC2 had high expression and low promoter methylation level in PCa, and its expression was correlated with regional node metastasis and disease-free survival. Cell proliferation, migration, invasion and EMT of PCa cells in vitro were greatly enhanced after RCC2 overexpression, while the RCC2 knockdown suppressed these processes. RNA-seq and GSEA results showed the Hedgehog signaling regulator Gli1 and Gli3 were involved in RCC2 knockdown DU145 cells. Gli1 was also a marker of cancer stem-like cells (CSCs). Mechanistically, RCC2 induced cell growth, EMT, CSCs markers through Gli1; inhibiting Gli1 expression using siGli1 or GLI inhibitor suppressed cell progression in vitro and tumor growth in vivo.

CONCLUSION

In summary, RCC2 promoted PCa development through Hh/Gli1 signaling pathway via regulating EMT and CSCs.

Concurrent Targeting of HDAC and PI3K to Overcome Phenotypic Heterogeneity of Castration-resistant and Neuroendocrine Prostate Cancers

Castration-resistant prostate cancer (CRPC) consists of multiple phenotypic subtypes including androgen receptor (AR)-active prostate cancer (ARPC) and neuroendocrine prostate cancer (NEPC). Tumor cells with these phenotypes can coexist between metastases within a patient and within an individual tumor. Treatments that are effective across CRPC subtypes are currently lacking. Histone deacetylation is crucial for the regulation of chromatin structure and maintenance of cancer cell state and activation of the PI3K/AKT/mTOR signaling cascade is a tumor growth-promoting pathway. We therefore investigated combined targeting of histone deacetylase (HDAC) and PI3K using a rationally designed dual inhibitor, fimepinostat, in CRPC subtypes in vitro and in vivo. Dual HDAC1/2 and PI3K/AKT pathway inhibition by fimepinostat led to robust tumor growth inhibition in both ARPC and NEPC models including cell line- and patient-derived xenografts. HDAC1/2 inhibition combined with PI3K/AKT inhibition was more effective than targeting each pathway alone, producing growth inhibitory effects through cell-cycle inhibition and apoptosis. Molecular profiling revealed on-target effects of combined HDAC1/2 and PI3K/AKT inhibition independent of tumor phenotype. Fimepinostat therapy was also associated with the suppression of lineage transcription factors including AR in ARPC and Achaete-scute homolog 1 (ASCL1) in NEPC. Together, these results indicate that fimepinostat represents a novel therapeutic that may be effective against both ARPC and NEPC through CRPC subtype-dependent and -independent mechanisms.

SIGNIFICANCE

CRPC is a heterogeneous disease constituting multiple phenotypic subtypes that often co-occur within tumors or across metastases in patients. Existing targeted therapies for CRPC do not take this into account. Here we show that fimepinostat, a dual HDAC1/2 and PI3K/AKT inhibitor investigated clinically in other cancer types but not prostate cancer, may overcome this heterogeneity by effectively inhibiting both ARPC and NEPC subtypes of CRPC.

Microbiota and the landscape of the prostate tumor microenvironment

Prostate cancer remains one of the most common causes of cancer-related death in men globally. Progression of prostate cancer to lethal metastatic disease is mediated by multiple contributors. The role of prostate microbiota and their metabolites in metastasis, therapeutic resistance to castration resistant prostate cancer (CRPC), and tumor relapse has yet to be fully investigated. Characterization of microflora can provide new mechanistic insights into the functional significance in the emergence of therapeutic resistance, identification of novel effective targeted therapies, and development of biomarkers during prostate cancer progression. The tumor microenvironment (TME) and its components work concurrently with the prostate microbiota in promoting prostate cancer development and progression to metastasis. In this article, we discuss the growing evidence on the functional contribution of microbiota to the phenotypic landscape of the TME and its effect on prostate cancer therapeutic targeting and recurrent disease.

Polyploid Giant Cancer Cells Generated from Human Cytomegalovirus-Infected Prostate Epithelial Cells

BACKGROUND

Prostate cancer is the most commonly diagnosed malignancy and the sixth leading cause of cancer death in men worldwide. Chromosomal instability (CIN) and polyploid giant cancer cells (PGCCs) have been considered predominant hallmarks of cancer. Recent clinical studies have proven the association of CIN, aneuploidy, and PGCCs with poor prognosis of prostate cancer (PCa). Evidence of HCMV transforming potential might indicate that HCMV may be involved in PCa.

METHODS

Herein, we underline the role of the high-risk HCMV-DB and -BL clinical strains in transforming prostate epithelial cells and assess the molecular and cellular oncogenic processes associated with PCa.

RESULTS

Oncogenesis parallels a sustained growth of "CMV-Transformed Prostate epithelial cells" or CTP cells that highly express Myc and EZH2, forming soft agar colonies and displaying stemness as well as mesenchymal features, hence promoting EMT as well as PGCCs and a spheroid appearance.

CONCLUSIONS

HCMV-induced Myc and EZH2 upregulation coupled with stemness and EMT traits in IE1-expressing CTP might highlight the potential role of HCMV in PCa development and encourage the use of anti-EZH2 and anti-HCMV in PCa treatment.

Novel signatures of prostate cancer progression and therapeutic resistance

INTRODUCTION

The extensive heterogeneity of prostate cancer (PCa) and multilayered complexity of progression to castration-resistant prostate cancer (CRPC) have contributed to the challenges of accurately monitoring advanced disease. Profiling of the tumor microenvironment with large-scale transcriptomic studies have identified gene signatures that predict biochemical recurrence, lymph node invasion, metastases, and development of therapeutic resistance through critical determinants driving CRPC.

AREAS COVERED

This review encompasses understanding of the role of different molecular determinants of PCa progression to lethal disease including the phenotypic dynamic of cell plasticity, EMT-MET interconversion, and signaling-pathways driving PCa cells to advance and metastasize. The value of liquid biopsies encompassing circulating tumor cells and extracellular vesicles to detect disease progression and emergence of therapeutic resistance in patients progressing to lethal disease is discussed. Relevant literature was added from PubMed portal.

EXPERT OPINION

Despite progress in the tumor-targeted therapeutics and biomarker discovery, distant metastasis and therapeutic resistance remain the major cause of mortality in patients with advanced CRPC. No single signature can encompass the tremendous phenotypic and genomic heterogeneity of PCa, but rather multi-threaded omics-derived and phenotypic markers tailored and validated into a multimodal signature.

Oxidative stress induced by Pollonein-LAAO, a new L-amino acid oxidase from Bothrops moojeni venom, prompts prostate tumor spheroid cell death and impairs the cellular invasion process in vitro

Cancer cells produce abnormal levels of reactive oxygen species (ROS) that contribute to promote their malignant phenotype. In this framework, we hypothesized that the change in ROS concentration above threshold could impair key events of prostate cancer cells (PC-3) progression. Our results demonstrated that Pollonein-LAAO, a new L-amino acid oxidase obtained from Bothrops moojeni venom, was cytotoxic to PC-3 cells in two-dimensional and in tumor spheroid assays. Pollonein-LAAO was able to increase the intracellular ROS generation that culminates in cell death from apoptosis by both intrinsic and extrinsic pathways due to the up-regulation of TP53, BAX, BAD, TNFRSF10B and CASP8. Additionally, Pollonein-LAAO reduced mitochondrial membrane potential and caused G0/G1 phase to delay, due to the up-regulation of CDKN1A and the down-regulation of the expression of CDK2 and E2F. Interestingly, Pollonein-LAAO inhibited critical steps of the cellular invasion process (migration, invasion and adhesion), due to the down-regulation of SNAI1, VIM, MMP2, ITGA2, ITGAV and ITGB3. Furthermore, the Pollonein-LAAO effects were associated with the intracellular ROS production, since the presence of catalase restored the invasiveness of PC-3 cells. In this sense, this study contributes to the potential use of Pollonein-LAAO as ROS-based agent to enhance the current understanding of cancer treatment strategies.

Epithelial-to-Mesenchymal Transition-Related Markers in Prostate Cancer: From Bench to Bedside

Prostate cancer (PCa) is the second most frequent type of cancer in men worldwide, with 288,300 new cases and 34,700 deaths estimated in the United States in 2023. Treatment options for early-stage disease include external beam radiation therapy, brachytherapy, radical prostatectomy, active surveillance, or a combination of these. In advanced cases, androgen-deprivation therapy (ADT) is considered the first-line therapy; however, PCa in most patients eventually progresses to castration-resistant prostate cancer (CRPC) despite ADT. Nonetheless, the transition from androgen-dependent to androgen-independent tumors is not yet fully understood. The physiological processes of epithelial-to-non-epithelial ("mesenchymal") transition (EMT) and mesenchymal-to-epithelial transition (MET) are essential for normal embryonic development; however, they have also been linked to higher tumor grade, metastatic progression, and treatment resistance. Due to this association, EMT and MET have been identified as important targets for novel cancer therapies, including CRPC. Here, we discuss the transcriptional factors and signaling pathways involved in EMT, in addition to the diagnostic and prognostic biomarkers that have been identified in these processes. We also tackle the various studies that have been conducted from bench to bedside and the current landscape of EMT-targeted therapies.

Epigenetic mechanism of therapeutic resistance and potential of epigenetic therapeutics in chemorefractory prostate cancer

Prostate cancer is the second leading cause of cancer death among men in the United States. Depending upon the histopathological subtypes of prostate cancers, various therapeutic options, such as androgen deprivation therapy (ADT), androgen receptor signaling inhibitors (ARSI), immunotherapy, and chemotherapy, are available to treat prostate cancer. While these therapeutics are effective in the initial stages during treatments, the tumors subsequently develop resistance to these therapies. Despite all the progress made so far, therapeutic resistance remains a major challenge in the treatment of prostate cancer. Although various mechanisms have been reported for the resistance development in prostate cancer, altered expression of genes either directly or indirectly involved in drug response pathways is a common event. In addition to the genetic basis of gene regulation such as mutations and gene amplifications, epigenetic alterations involved in the aberrant expression of genes have frequently been shown to be associated not only with cancer initiation and progression but also with therapeutic resistance development. There are several review articles compiling reports on genetic mechanisms involved in therapeutic resistance in prostate cancer. However, epigenetic mechanisms for the therapeutic resistance development in prostate cancer have not yet been summarized in a review article. Therefore, the objective of this article is to compile various reports and provide a comprehensive review of the epigenetic aberrations, and aberrant expression of genes by epigenetic mechanisms involved in CRPCs and therapeutic resistance development in prostate cancer. Additionally, the potential of epigenetic-based therapeutics in the treatment of chemorefractory prostate cancer as evidenced by clinical trials has also been discussed.

Heterogeneity and plasticity of epithelial-mesenchymal transition (EMT) in cancer metastasis: Focusing on partial EMT and regulatory mechanisms

Epithelial-mesenchymal transition (EMT) or mesenchymal-epithelial transition (MET) plays critical roles in cancer metastasis. Recent studies, especially those based on single-cell sequencing, have revealed that EMT is not a binary process, but a heterogeneous and dynamic disposition with intermediary or partial EMT states. Multiple double-negative feedback loops involved by EMT-related transcription factors (EMT-TFs) have been identified. These feedback loops between EMT drivers and MET drivers finely regulate the EMT transition state of the cell. In this review, the general characteristics, biomarkers and molecular mechanisms of different EMT transition states were summarized. We additionally discussed the direct and indirect roles of EMT transition state in tumour metastasis. More importantly, this article provides direct evidence that the heterogeneity of EMT is closely related to the poor prognosis in gastric cancer. Notably, a seesaw model was proposed to explain how tumour cells regulate themselves to remain in specific EMT transition states, including epithelial state, hybrid/intermediate state and mesenchymal state. Additionally, this article also provides a review of the current status, limitations and future perspectives of EMT signalling in clinical applications.

Adipose Tissue-Derived Extracellular Vesicles Contribute to Phenotypic Plasticity of Prostate Cancer Cells

Metastatic prostate cancer is one of the leading causes of male cancer deaths in the western world. Obesity significantly increases the risk of metastatic disease and is associated with a higher mortality rate. Systemic chronic inflammation can result from a variety of conditions, including obesity, where adipose tissue inflammation is a major contributor. Adipose tissue endothelial cells (EC) exposed to inflammation become dysfunctional and produce a secretome, including extracellular vesicles (EV), that can impact function of cells in distant tissues, including malignant cells. The aim of this study was to explore the potential role of EVs produced by obese adipose tissue and the ECs exposed to pro-inflammatory cytokines on prostate cancer phenotypic plasticity in vitro. We demonstrate that PC3ML metastatic prostate cancer cells exposed to EVs from adipose tissue ECs and to EVs from human adipose tissue total explants display reduced invasion and increased proliferation. The latter functional changes could be attributed to the EV miRNA cargo. We also show that the functional shift is TWIST1-dependent and is consistent with mesenchymal-to-epithelial transition, which is key to establishment of secondary tumor growth. Understanding the complex effects of EVs on prostate cancer cells of different phenotypes is key before their intended use as therapeutics.

Protein Kinase D3 (PKD3) Requires Hsp90 for Stability and Promotion of Prostate Cancer Cell Migration

Prostate cancer metastasis is a significant cause of mortality in men. PKD3 facilitates tumor growth and metastasis, however, its regulation is largely unclear. The Hsp90 chaperone stabilizes an array of signaling client proteins, thus is an enabler of the malignant phenotype. Here, using different prostate cancer cell lines, we report that Hsp90 ensures PKD3 conformational stability and function to promote cancer cell migration. We found that pharmacological inhibition of either PKDs or Hsp90 dose-dependently abrogated the migration of DU145 and PC3 metastatic prostate cancer cells. Hsp90 inhibition by ganetespib caused a dose-dependent depletion of PKD2, PKD3, and Akt, which are all involved in metastasis formation. Proximity ligation assay and immunoprecipitation experiments demonstrated a physical interaction between Hsp90 and PKD3. Inhibition of the chaperone-client interaction induced misfolding and proteasomal degradation of PKD3. PKD3 siRNA combined with ganetespib treatment demonstrated a specific involvement of PKD3 in DU145 and PC3 cell migration, which was entirely dependent on Hsp90. Finally, ectopic expression of PKD3 enhanced migration of non-metastatic LNCaP cells in an Hsp90-dependent manner. Altogether, our findings identify PKD3 as an Hsp90 client and uncover a potential mechanism of Hsp90 in prostate cancer metastasis. The molecular interaction revealed here may regulate other biological and pathological functions.

Radioresistance Mechanisms in Prostate Cancer Cell Lines Surviving Ultra-Hypo-Fractionated EBRT: Implications and Possible Clinical Applications

The use of a higher dose per fraction to overcome the high radioresistance of prostate cancer cells has been unsuccessfully proposed. Herein, we present PC3 and DU-145, castration-resistant prostate cancer cell lines that survived a clinically used ultra-higher dose per fraction, namely, radioresistant PC3 and DU-145 cells (PC3RR and DU-145RR). Compared to PC3, PC3RR showed a higher level of aggressive behaviour, with enhanced clonogenic potential, DNA damage repair, migration ability and cancer stem cell features. Furthermore, compared to PC3, PC3RR more efficiently survived further radiation by increasing proliferation and down-regulating pro-apoptotic proteins. No significant changes of the above parameters were described in DU-145RR, suggesting that different prostate cancer cell lines that survive ultra-higher dose per fraction do not display the same grade of aggressive phenotype. Furthermore, both PC3RR and DU-145RR increased antioxidant enzymes and mesenchymal markers. Our data suggest that different molecular mechanisms could be potential targets for future treatments plans based on sequential strategies and synergistic effects of different modalities, possibly in a patient-tailored fashion. Moreover, PC3RR cells displayed an increase in specific markers involved in bone remodeling, indicating that radiotherapy selects a PC3 population capable of migrating to secondary metastatic sites. Finally, PC3RR cells showed a better sensitivity to Docetaxel as compared to native PC3 cells. This suggests that a subset of patients with castration-resistant metastatic disease could benefit from upfront Docetaxel treatment after the failure of radiotherapy.

GPX2 predicts recurrence-free survival and triggers the Wnt/β-catenin/EMT pathway in prostate cancer

Objective

This study aimed to establish a prognostic model related to prostate cancer (PCa) recurrence-free survival (RFS) and identify biomarkers.

Methods

The RFS prognostic model and key genes associated with PCa were established using Least Absolute Shrinkage and Selection Operator (LASSO) and Cox regression from the Cancer Genome Atlas (TCGA)-PRAD and the Gene Expression Omnibus (GEO) GSE46602 datasets. The weighted gene co-expression network (WGCNA) was used to analyze the obtained key modules and genes, and gene set enrichment analysis (GSEA) was performed. The phenotype and mechanism were verified in vitro.

Results

A total of 18 genes were obtained by LASSO regression, and an RFS model was established and verified (TCGA, AUC: 0.774; GSE70768, AUC: 0.759). Three key genes were obtained using multivariate Cox regression. WGCNA analysis obtained the blue module closely related to the Gleason score (cor = -0.22, P = 3.3e - 05) and the unique gene glutathione peroxidase 2 (GPX2). Immunohistochemical analysis showed that the expression of GPX2 was significantly higher in patients with PCa than in patients with benign prostatic hyperplasia (P < 0.05), but there was no significant correlation with the Gleason score (GSE46602 and GSE6919 verified), which was also verified in the GSE46602 and GSE6919 datasets. The GSEA results showed that GPX2 expression was mainly related to the epithelial-mesenchymal transition (EMT) and Wnt pathways. Additionally, GPX2 expression significantly correlated with eight kinds of immune cells. In human PCa cell lines LNCaP and 22RV1, si-GPX2 inhibited proliferation and invasion, and induced apoptosis when compared with si-NC. The protein expression of Wnt3a, glycogen synthase kinase 3β (GSK3β), phosphorylated (p)-GSK3β, β-catenin, p-β-catenin, c-myc, cyclin D1, and vimentin decreased; the expression of E-cadherin increased; and the results for over-GPX2 were opposite to those for over-NC. The protein expression of GPX2 decreased, and β-catenin was unchanged in the si-GPX2+ SKL2001 group compared with the si-NC group.

Conclusion

We successfully constructed the PCa RFS prognostic model, obtained RFS-related biomarker GPX2, and found that GPX2 regulated PCa progression and triggered Wnt/β-catenin/EMT pathway molecular changes.

Spheroid-induced heterogeneity and plasticity of uveal melanoma cells

PURPOSE

The mechanism underlying cancer heterogeneity and plasticity remains elusive, in spite of the fact that multiple hypotheses have been put forward. We intended to clarify this heterogeneity in uveal melanoma (UM) by looking for evidence of cancer stem cell involvement and a potential role of ZEB1 in cancer cell plasticity.

METHODS

Spheroids derived from human UM cells as well as xenograft tumors in nude mice were dissected for signs of heterogeneity and plasticity. Two human UM cell lines were studied: the epithelioid type C918 cell line and the spindle type OCM1 cell line. We knocked down ZEB1 in both cell lines to investigate its involvement in the regulation of stem-like cell formation and vascularization by qRT-PCR, immunohistochemistry, flow cytometry, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assays.

RESULTS

We found that a small side population (SP) in OCM1 showed stem cell-like properties such as heterogeneity, remote dissemination and nuclear dye exclusion after spheroid formation in vitro. ZEB1 regulated UM stem cell generation indirectly by promoting cell proliferation to form large size tumors in vivo and spheroid in vitro, and directly by binding to stemness genes such as TERT and ABCB1. In addition, we found that ZEB1 participates in vasculogenic mimicry system formation through the regulation of CD34 and VE-cadherin expression.

CONCLUSIONS

From our data we conclude that cancer stem cells may contribute to UM heterogeneity and plasticity and that ZEB1 may play a regulatory role in it.