Single-cell analysis revealing the metabolic landscape of prostate cancer.

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.

Heat shock factor 1 directly regulates transsulfuration pathway to promote prostate cancer proliferation and survival.

There are limited therapeutic options for patients with advanced prostate cancer (PCa). We previously found that heat shock factor 1 (HSF1) expression is increased in PCa and is an actionable target. In this manuscript, we identify that HSF1 regulates the conversion of homocysteine to cystathionine in the transsulfuration pathway by altering levels of cystathionine-ß-synthase (CBS). We find that HSF1 directly binds the CBS gene and upregulates CBS mRNA levels. Targeting CBS decreases PCa growth and induces tumor cell death while benign prostate cells are largely unaffected. Combined inhibition of HSF1 and CBS results in more pronounced inhibition of PCa cell proliferation and reduction of transsulfuration pathway metabolites. Combination of HSF1 and CBS knockout decreases tumor size for a small cell PCa xenograft mouse model. Our study thus provides new insights into the molecular mechanism of HSF1 function and an effective therapeutic strategy against advanced PCa.

Targeting glutamine dependence with DRP-104 inhibits proliferation and tumor growth of castration-resistant prostate cancer.

BACKGROUND: Prostate cancer (PCa) continues to be one of the leading causes of cancer deaths in men. While androgen deprivation therapy is initially effective, castration-resistant PCa (CRPC) often recurs and has limited treatment options. Our previous study identified glutamine metabolism to be critical for CRPC growth. The glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON) blocks both carbon and nitrogen pathways but has dose-limiting toxicity. The prodrug DRP-104 is expected to be preferentially converted to DON in tumor cells to inhibit glutamine utilization with minimal toxicity. However, CRPC cells' susceptibility to DRP-104 remains unclear. METHODS: Human PCa cell lines (LNCaP, LAPC4, C4-2/MDVR, PC-3, 22RV1, NCI-H660) were treated with DRP-104, and effects on proliferation and cell death were assessed. Unbiased metabolic profiling and isotope tracing evaluated the effects of DRP-104 on glutamine pathways. Efficacy of DRP-104 in vivo was evaluated in a mouse xenograft model of neuroendocrine PCa, NCI-H660. RESULTS: DRP-104 inhibited proliferation and induced apoptosis in CRPC cell lines. Metabolite profiling showed decreases in the tricarboxylic acid cycle and nucleotide synthesis metabolites. Glutamine isotope tracing confirmed the blockade of both carbon pathway and nitrogen pathways. DRP-104 treated CRPC cells were rescued by the addition of nucleosides. DRP-104 inhibited neuroendocrine PCa xenograft growth without detectable toxicity. CONCLUSIONS: The prodrug DRP-104 blocks glutamine carbon and nitrogen utilization, thereby inhibiting CRPC growth and inducing apoptosis. Targeting glutamine metabolism pathways with DRP-104 represents a promising therapeutic strategy for CRPC.

Oncofetal protein glypican-3 is a biomarker and critical regulator of function for neuroendocrine cells in prostate cancer.

Neuroendocrine (NE) cells comprise ~1% of epithelial cells in benign prostate and prostatic adenocarcinoma (PCa). However, they become enriched in hormonally treated and castration-resistant PCa (CRPC). In addition, close to 20% of hormonally treated tumors recur as small cell NE carcinoma (SCNC), composed entirely of NE cells, which may be the result of clonal expansion or lineage plasticity. Since NE cells do not express androgen receptors (ARs), they are resistant to hormonal therapy and contribute to therapy failure. Here, we describe the identification of glypican-3 (GPC3) as an oncofetal cell surface protein specific to NE cells in prostate cancer. Functional studies revealed that GPC3 is critical to the viability of NE tumor cells and tumors displaying NE differentiation and that it regulates calcium homeostasis and signaling. Since our results demonstrate that GPC3 is specifically expressed by NE cells, patients with confirmed SCNC may qualify for GPC3-targeted therapy which has been developed in the context of liver cancer and displays minimal toxicity due to its tumor-specific expression. © 2023 The Pathological Society of Great Britain and Ireland.

The role of glutamine metabolism in castration-resistant prostate cancer.

Reprogramming of metabolism is a hallmark of tumors, which has been explored for therapeutic purposes. Prostate cancer (PCa), particularly advanced and therapy-resistant PCa, displays unique metabolic properties. Targeting metabolic vulnerabilities in PCa may benefit patients who have exhausted currently available treatment options and improve clinical outcomes. Among the many nutrients, glutamine has been shown to play a central role in the metabolic reprogramming of advanced PCa. In addition to amino acid metabolism, glutamine is also widely involved in the synthesis of other macromolecules and biomasses. Targeting glutamine metabolic network by maximally inhibiting glutamine utilization in tumor cells may significantly add to treatment options for many patients. This review summarizes the metabolic landscape of PCa, with a particular focus on recent studies of how glutamine metabolism alterations affect therapeutic resistance and disease progression of PCa, and suggests novel therapeutic strategies.

Ectopic JAK-STAT activation enables the transition to a stem-like and multilineage state conferring AR-targeted therapy resistance.

Emerging evidence indicates that various cancers can gain resistance to targeted therapies by acquiring lineage plasticity. Although various genomic and transcriptomic aberrations correlate with lineage plasticity, the molecular mechanisms enabling the acquisition of lineage plasticity have not been fully elucidated. We reveal that Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling is a crucial executor in promoting lineage plasticity-driven androgen receptor (AR)-targeted therapy resistance in prostate cancer. Importantly, ectopic JAK-STAT activation is specifically required for the resistance of stem-like subclones expressing multilineage transcriptional programs but not subclones exclusively expressing the neuroendocrine-like lineage program. Both genetic and pharmaceutical inhibition of JAK-STAT signaling resensitizes resistant tumors to AR-targeted therapy. Together, these results suggest that JAK-STAT are compelling therapeutic targets for overcoming lineage plasticity-driven AR-targeted therapy resistance.

Reprogramming hormone-sensitive prostate cancer to a lethal neuroendocrine cancer lineage by mitochondrial pyruvate carrier (MPC).

Cell lineage reprogramming is the main approach for cancer cells to acquire drug resistance and escape targeted therapy. The use of potent targeted therapies in cancers has led to the development of highly aggressive carcinoma, including neuroendocrine prostate cancer (NEPC). Although metabolic reprogramming has been reported to be essential for tumor growth and energy production, the relationship between metabolic reprogramming and lineage differentiation which can cause hormone therapy resistance has never been reported in prostate cancer (PCa). Moreover, as there is still no efficient therapy for NEPC, it is urgent to reverse this lineage differentiation during the hormone therapy. Here for the first time, we used in vitro and in vivo human PCa models to study the effect of metabolic reprogramming on the lineage differentiation from the androgen receptor (AR)-dependent adenocarcinoma to AR-independent NEPC. This lineage differentiation leads to antiandrogen drug resistance and tumor development. This phenotype is enabled by the loss of mitochondrial pyruvate carrier (MPC), the gate for mitochondrial pyruvate influx, and can be reversed by MPC overexpression. Morphologic and cellular studies also demonstrate that the pyruvate kinase M2 (PKM2) involved epithelium-mesenchymal transition process mediated this lineage alteration. Its inhibition is a potential treatment for MPC-lo tumors. All of these results suggest that metabolic rewiring can act as a starter for increased cellular plasticity which leads to antiandrogen therapy resistance through lineage differentiation. This study provides us with a potent treatment target for therapy-induced, enzalutamide-resistant NE-like prostate cancer.

Targeting glutamine metabolism network for the treatment of therapy-resistant prostate cancer.

Advanced and aggressive prostate cancer (PCa) depends on glutamine for survival and proliferation. We have previously shown that inhibition of glutaminase 1, which catalyzes the rate-limiting step of glutamine catabolism, achieves significant therapeutic effect; however, therapy resistance is inevitable. Here we report that while the glutamine carbon is critical to PCa survival, a parallel pathway of glutamine nitrogen catabolism that actively contributes to pyrimidine assembly is equally important for PCa cells. Importantly, we demonstrate a reciprocal feedback mechanism between glutamine carbon and nitrogen pathways which leads to therapy resistance when one of the two pathways is inhibited. Combination treatment to inhibit both pathways simultaneously yields better clinical outcome for advanced PCa patients.

Characterization of a castrate-resistant prostate cancer xenograft derived from a patient of West African ancestry.

BACKGROUND: Prostate cancer is a clinically and molecularly heterogeneous disease, with highest incidence and mortality among men of African ancestry. To date, prostate cancer patient-derived xenograft (PCPDX) models to study this disease have been difficult to establish because of limited specimen availability and poor uptake rates in immunodeficient mice. Ancestrally diverse PCPDXs are even more rare, and only six PCPDXs from self-identified African American patients from one institution were recently made available. METHODS: In the present study, we established a PCPDX from prostate cancer tissue from a patient of estimated 90% West African ancestry with metastatic castration resistant disease, and characterized this model's pathology, karyotype, hotspot mutations, copy number, gene fusions, gene expression, growth rate in normal and castrated mice, therapeutic response, and experimental metastasis. RESULTS: This PCPDX has a mutation in TP53 and loss of PTEN and RB1. We have documented a 100% take rate in mice after thawing the PCPDX tumor from frozen stock. The PCPDX is castrate- and docetaxel-resistant and cisplatin-sensitive, and has gene expression patterns associated with such drug responses. After tail vein injection, the PCPDX tumor cells can colonize the lungs of mice. CONCLUSION: This PCPDX, along with others that are established and characterized, will be useful pre-clinically for studying the heterogeneity of prostate cancer biology and testing new therapeutics in models expected to be reflective of the clinical setting.

Outcomes of Robot-Assisted Laparoscopic Isthmus Division Using Endoscopic Transection Equipment in the Treatment of Symptomatic Horseshoe Kidney.

Background: The surgical treatment of horseshoe kidney (HSK) remains a huge challenge because of the complex anatomy and abnormal blood vessel distribution. Therefore, this study aimed to evaluate the surgical technique and outcomes of robot-assisted laparoscopic isthmus division using endoscopic transection equipment (endoscopic linear stapler; Ethicon, ECHELON 60 FLEX™) in the treatment of symptomatic HSK and to conduct a literature review. Materials and Methods: Patients with HSK who underwent robot-assisted laparoscopic isthmus division using endoscopic transection equipment from August 2015 to August 2019 at the First Affiliated Hospital of Anhui Medical University in China were recruited. Isthmus division was conducted using an endoscopic linear stapler. Results: All 10 surgeries were performed successfully. Major organs and large blood vessels were effectively protected. Only 1 patient presented with postoperative perinephric effusion. The mean operative time was 179 minutes, and the mean length of the postoperative hospital stay was 6 days. During the 1- to 5-year follow-up, all patients were cured with mitigated symptoms and improved renal function, except for 1 patient with transitional cell carcinoma who died of multiple metastases 18 months postoperatively. Conclusion: Robot-assisted laparoscopic isthmus division using endoscopic transection equipment is a safe and effective method to manage patients with symptomatic HSK and to help them have few complications and quick recovery. Clinical Trial Registration No: Quick-PJ 2021-03-18.

ELOVL5-Mediated Long Chain Fatty Acid Elongation Contributes to Enzalutamide Resistance of Prostate Cancer.

Prostate cancer (PCa) exhibits an elevated level of de novo lipogenesis that provides both energy and basic metabolites for its malignant development. Long-chain polyunsaturated fatty acids (PUFAs) are elongated and desaturated from palmitate but their effects on PCa progression remain largely unknown. Here, we showed that PUFAs were significantly upregulated by androgen deprivation therapy (ADT) and elevated in neuroendocrine (NE)-like PCa cells. The key enzyme of PUFA elongation, ELOVL5, was overexpressed in NE-like PCa cells as well. Furthermore, we demonstrated that knocking down ELOVL5 in enzalutamide resistant NE-like PCa cells diminished the neuroendocrine phenotypes and enzalutamide resistance, while overexpressing ELOVL5 augmented the enzalutamide resistance of PCa cells in vitro and in vivo. Mechanistically, ELOVL5-mediated PUFA elongation enhanced the lipid raft-associated AKT-mTOR signaling activation and therefore contributes to the enzalutamide resistance. These findings suggest that ELOLV5-mediated PUFA elongation may be a potential novel target for the treatment of enzalutamide resistant NE-like PCa.

Cistrome analysis of YY1 uncovers a regulatory axis of YY1:BRD2/4-PFKP during tumorigenesis of advanced prostate cancer.

Castration-resistant prostate cancer (CRPC) is a terminal disease and the molecular underpinnings of CRPC development need to be better understood in order to improve its treatment. Here, we report that a transcription factor Yin Yang 1 (YY1) is significantly overexpressed during prostate cancer progression. Functional and cistrome studies of YY1 uncover its roles in promoting prostate oncogenesis in vitro and in vivo, as well as sustaining tumor metabolism including the Warburg effect and mitochondria respiration. Additionally, our integrated genomics and interactome profiling in prostate tumor show that YY1 and bromodomain-containing proteins (BRD2/4) co-occupy a majority of gene-regulatory elements, coactivating downstream targets. Via gene loss-of-function and rescue studies and mutagenesis of YY1-bound cis-elements, we unveil an oncogenic pathway in which YY1 directly binds and activates PFKP, a gene encoding the rate-limiting enzyme for glycolysis, significantly contributing to the YY1-enforced Warburg effect and malignant growth. Altogether, this study supports a master regulator role for YY1 in prostate tumorigenesis and reveals a YY1:BRD2/4-PFKP axis operating in advanced prostate cancer with implications for therapy.

A glutaminase isoform switch drives therapeutic resistance and disease progression of prostate cancer.

Cellular metabolism in cancer is significantly altered to support the uncontrolled tumor growth. How metabolic alterations contribute to hormonal therapy resistance and disease progression in prostate cancer (PCa) remains poorly understood. Here we report a glutaminase isoform switch mechanism that mediates the initial therapeutic effect but eventual failure of hormonal therapy of PCa. Androgen deprivation therapy inhibits the expression of kidney-type glutaminase (KGA), a splicing isoform of glutaminase 1 (GLS1) up-regulated by androgen receptor (AR), to achieve therapeutic effect by suppressing glutaminolysis. Eventually the tumor cells switch to the expression of glutaminase C (GAC), an androgen-independent GLS1 isoform with more potent enzymatic activity, under the androgen-deprived condition. This switch leads to increased glutamine utilization, hyperproliferation, and aggressive behavior of tumor cells. Pharmacological inhibition or RNA interference of GAC shows better treatment effect for castration-resistant PCa than for hormone-sensitive PCa in vitro and in vivo. In summary, we have identified a metabolic function of AR action in PCa and discovered that the GLS1 isoform switch is one of the key mechanisms in therapeutic resistance and disease progression.

N-cadherin inhibitor creates a microenvironment that protect TILs from immune checkpoints and Treg cells.

BACKGROUND: Few patients with prostate cancer benefit from current immunotherapies. Therefore, we aimed to explore new strategies to change this paradigm. METHODS: Human tissues, cell lines and in vivo experiments were used to determine whether and how N-cadherin impacts the production of programmed death ligand-1 (PD-L1) and indole amine 2,3-dioxygenase (IDO-1) and whether N-cadherin can increase the production of effector (e)Treg cells. Then, we used PC3-bearing humanized non-obese diabetic/severe combined immunodeficiency IL2Rγnull (hNSG) mice with an intravenous injection of human CD34+ hematopoietic stem cells into the tail vein to evaluate whether the N-cadherin antagonist N-Ac-CHAVC-NH2 (designated ADH-1) could improve the therapeutic effect of tumor-infiltrating lymphocyte (TIL)-related treatment. RESULTS: N-cadherin dramatically upregulated the expression of PD-L1 and IDO-1 through IFN-γ (interferongamma) signaling and increasing the production of free fatty acids that could promote the generation of eTreg cells. In preclinical experiments, immune reconstitution mediated by TILs slowed tumor growth and extended the survival time; however, this effect disappeared after immune system suppression by PD-L1, IDO-1 and eTreg cells. Furthermore, ADH-1 effectively reduced immunosuppression and enhanced TIL-related therapy. CONCLUSIONS: These data show that the N-cadherin antagonist ADH-1 promotes TIL antitumor responses. This important hurdle must be overcome for tumors to respond to immunotherapy.

Identifying the role of apolipoprotein A-I in prostate cancer.

Although localized prostate cancer (PCa) can be cured by prostatectomy and radiotherapy, the development of effective therapeutic approaches for advanced prostate cancer, including castration-resistant PCa (CRPC) and neuroendocrine PCa (NEPC), is lagging far behind. Identifying a novel prognostic and diagnostic biomarker for early diagnosis and intervention is an urgent clinical need. Here, we report that apolipoprotein A-I (ApoA-I), the major component of high-density lipoprotein (HDL), is upregulated in PCa based on both bioinformatics and experimental evidence. The fact that advanced PCa shows strong ApoA-I expression reflects its potential role in driving therapeutic resistance and disease progression by reprogramming the lipid metabolic network of tumor cells. Molecularly, ApoA-I is regulated by MYC, a frequently amplified oncogene in late-stage PCa. Altogether, our findings have revealed a novel indicator to predict prognosis and recurrence, which would benefit patients who are prone to progress to metastasis or even NEPC, which is the lethal subtype of PCa.

Long Non-Coding RNA SNHG1 Regulates the Wnt/ß-Catenin and PI3K/AKT/mTOR Signaling Pathways via EZH2 to Affect the Proliferation, Apoptosis, and Autophagy of Prostate Cancer Cell.

BACKGROUND: Prostate cancer (PCa) is the most common malignant cancer in western developed countries, which has seriously threatened the life style and life quality of men. Its pathogenesis and causes remain indistinct. Currently, it is found that lncRNA-SNHG1 (SNHG1) is highly expressed in multiple tumors with proto-oncogene effect, but its function and mechanism in PCa need to be further studied. METHODS: The expression of SNHG1 and EZH2 was detected by RT-qPCR in the 20 pairs of PCa tissue, adjacent tissue and PCa cell lines. They were transfected with siRNA NC, SNHG1 siRNA, EZH2 siRNA, SNHG1 siRNA+empty, and SNHG1 siRNA+EZH2 overexpression. Then, MTT and colony formation assay were used to detect the proliferation and cloning ability of PCa cells LNCaP and PC3. Transwell and flow cytometry were used to measure cell migration and invasion ability and apoptosis level respectively. Immunofluorescence was used to detect the LC3 spot formation. Western blot was used to detect the expression of the autophagy-related proteins, and PI3K/AKT/mTOR and Wnt/ß-catenin signaling pathway related proteins. Finally, in vivo nude mice tumorigenesis experiment to explore the effect of SNHG1 expression on PCa. RESULTS: We found that SNHG1 and EZH2 were up-regulated in PCa tissue and cells. The expression of SNHG1 and EZH2 was positively correlated. RNA pull down and RNA IP assay further confirmed that SNHG1 bound to EZH2. The proliferation, colony formation, migration and invasion of LNCaP and PC3 cells were significantly reduced with the interference with SNHG1or EZH2 compared with the control group. The related proteins of Wnt/ß-catenin and PI3K/AKT/mTOR signaling pathway were significantly reduced after the interference with SNHG1 or EZH2; after simultaneous interference with SNHG1 and overexpression of EZH2, the functional effects on LNCaP and PC3 cells interfered with SNHG1 were reversed. These results were also confirmed in vivo nude mice tumor formation experiments. CONCLUSIONS: This study reveals that lncRNA-SNHG1 regulates Wnt/ß-catenin and PI3K/AKT/mTOR signaling pathways via EZH2 gene to affect proliferation, apoptosis and autophagy of PCa cells. This experiment provides ideas and experimental basis for the improvement and treatment of PCa.

N­Myc induces the tumor progression of prostate cancer by regulating FSCN1.

The oncoprotein N­Myc has a carcinogenic effect in numerous types of cancer, and it can cause castration resistance in prostate cancer (PCa), and leads to the development of small cell neuroendocrine cancer by regulating multiple target genes. Immunohistochemical staining, RT­qPCR, western blotting, wound healing and CCK­8 assays were used to detect the expression of N­Myc and FSCN1 as well as AR and CgA at the human level and cell level. The immunohistochemical results revealed that the protein levels of N­Myc proto­oncogene protein (N­Myc) and fascin (FSCN1) in PCa were significantly higher than that of hyperplastic tissues (P<0.05), and there was a weak correlation between them (P=0.002). In vitro, N­Myc and FSCN1 were overexpressed in LNCaP and C4­2 cell lines. The results revealed the promoting effect of N­Myc and FSCN1 on malignant progression of PCa. In addition, the endogenous FSCN1 was knocked down in the C4­2 cell line, and the results revealed that the silencing of FSCN1 enhanced the expression of N­Myc and weakened the expression of the neuroendocrine marker CgA. Therefore, the present findings indicated that N­Myc may promote the malignant process of PCa by regulating FSCN1 and FSCN1 may have a reverse regulatory effect on N­Myc.

Therapeutic potential of ReACp53 targeting mutant p53 protein in CRPC.

BACKGROUNDS: p53 is a tumor suppressor that prevents cancer onset and progression, and mutations in the p53 gene cause loss of the tumor suppressor function of the protein. The mutant p53 protein in tumor cells can form aggregates which contribute to the dominant-negative effect over the wild-type p53 protein, causing loss of p53 tumor suppression or gain of novel oncogenic functions. Mutations in p53 have been implicated in the pathogenesis of primary prostate cancer (PCa), and are often detected in recurrent and metastatic disease. Thus, targeting mutant p53 may constitute an alternative therapeutic strategy for advanced PCa for which there are no other viable options. METHODS: In this study, we used immunoprecipitation, immunofluorescence, clonogenic survival, and cell proliferation assays, flow cytometric analysis and in vivo xenograft to investigate the biological effects of ReACp53, a cell-permeable peptide inhibitor of p53 aggregation, on mutant p53-carrying PCa cells. RESULTS: Our results show that ReACp53 targets amyloid aggregates of mutant p53 protein and restores the p53 nuclear function as transcriptional factor, induces mitochondrial cell death and reduces DNA synthesis of mutant p53-carrying PCa cells; ReACp53 also inhibits xenograft tumor growth in vivo. CONCLUSIONS: The data presented here suggest a therapeutic potential of targeting mutant p53 protein in advanced PCa setting, which has a clinical impact for aggressive PCa with transforming how such tumors are managed.

Targeting cellular heterogeneity with CXCR2 blockade for the treatment of therapy-resistant prostate cancer.

Hormonal therapy targeting androgen receptor (AR) is initially effective to treat prostate cancer (PCa), but it eventually fails. It has been hypothesized that cellular heterogeneity of PCa, consisting of AR+ luminal tumor cells and AR- neuroendocrine (NE) tumor cells, may contribute to therapy failure. Here, we describe the successful purification of NE cells from primary fresh human prostate adenocarcinoma based on the cell surface receptor C-X-C motif chemokine receptor 2 (CXCR2). Functional studies revealed CXCR2 to be a driver of the NE phenotype, including loss of AR expression, lineage plasticity, and resistance to hormonal therapy. CXCR2-driven NE cells were critical for the tumor microenvironment by providing a survival niche for the AR+ luminal cells. We demonstrate that the combination of CXCR2 inhibition and AR targeting is an effective treatment strategy in mouse xenograft models. Such a strategy has the potential to overcome therapy resistance caused by tumor cell heterogeneity.