Progression Of Advanced Prostate Cancer Research Articles

Abstract 396: Effects of hypoxia on cell proliferation and lipidome profile in treatment-resistant prostate cancer cells

Abstract Background: Low tissue content of oxygen i.e. hypoxia is typical in prostate cancer (PCa) tumor microenvironment. Hypoxia is also associated with PCa progression and treatment resistance. Modulation of lipid and cholesterol metabolism seems to be one way how tumor cells adapt to hypoxia. However, not much is known about lipidomic profiles in hypoxic condition in advanced PCa and treatment resistance. Aim: The aim of this study was to evaluate the impact of hypoxia on treatment-resistant PCa cells and investigate alterations in the lipidome under hypoxic conditions. Material and Methods: Testosterone (T)-sensitive, T-independent (castration-resistant), and enzalutamide (enza)-resistant VCaP PCa cells were cultured for three days under hypoxia (1% O2) and compared with cells grown under normoxia (21% O2). Additionally, cells were treated with the drugs SREBP-inhibitor fatostatin and mevalonate-pathway inhibitor simvastatin to examine the effects of modulating lipid and cholesterol production on hypoxia responses. Relative cell growth by crystal violet staining and live/dead cell ratio were evaluated after each treatment. Intracellular lipidome was measured using liquid chromatography coupled with MS/MS method. Random forest classification was used of the selection of the lipids. Based on the classification, concentration differences between the groups were calculated. Results: Growth of the T-sensitive and castration-resistant cells was decreased under hypoxia compared to normoxia. However, enza-resistant cells tolerated hypoxic conditions. Lipid-modifying drugs exhibited similar inhibitory effects on cell growth in both normoxia and hypoxia. Based on live/dead cell ratio, hypoxia induced cell death. Lipidome profiles varied markedly by oxygen content and cellular treatment resistance profile. Simvastatin treatment also influenced lipidome profiles. Conclusions: Enza-resistant advanced PCa cells tolerated hypoxic conditions better compared to T-sensitive and T-independent cells. Lipidome was different between cell lines but also in hypoxia compared to normoxia, supporting its importance for PCa cells under varying conditions. Interference with lipid metabolism leads to growth inhibition regardless of hypoxia. These findings could be used in identifying potential markers for predicting or delaying disease progression in advanced PCa. Future studies should explore the efficacy of various lipidome-modulating drugs in delaying disease progression in PCa. Citation Format: Aino Siltari, Kalle Välitalo, Tomas Laamanen, Kaisa Tornberg, Alvar Saarinen, Joose Kreuzer, Heimo Syvälä, Teuvo L. Tammela, Pauliina Ilmonen, Pasi Kallio, Teemu J. Murtola. Effects of hypoxia on cell proliferation and lipidome profile in treatment-resistant prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 396.

Decoding the intermolecular recognition mode of a potent anticancer drug, abiraterone with human serum albumin: Assessments through spectroscopic and computational techniques

Abiraterone (ABR) is an FDA-approved anticancer drug that possesses repressing properties against the progression of advanced prostate cancer. The combination of bioactive molecules with proteins in blood circulation is the primary determinant of their potential therapeutic effectiveness. Therefore, the interaction characteristics of ABR with the leading carrier protein, human serum albumin (HSA) was evaluated using multi-spectroscopic and computational techniques. The obtained results showed enhancement of HSA fluorescence upon ABR addition through a static process, and affirmed the complexation between ABR and HSA. Whereas a moderate binding strength in ABR–HSA complexation was manifested, the complex was predicted to be stabilized through hydrophobic interactions, van der Waals forces and hydrogen bonding. Inclusion of ABR to HSA appreciably guarded temperature-induced destabilization of the protein, however, it altered the encompassing medium near Trp and Tyr residues of HSA. ABR was detected to favor binding at subdomain IIIA (Sudlow's site II) of HSA and the constancy of the ABR–HSA complex was revealed.

UP51 - HSD3B1 genotyping and advanced prostate cancer progression and therapy

UP51 - HSD3B1 genotyping and advanced prostate cancer progression and therapy

Advances in Research on Risk Factors for Disease Progression in Advanced Prostate Cancer

Advanced prostate cancer has mostly lost the chance of surgery, and has a low 5-year survival rate and high mortality rate. Therefore, exploring the risk factors for advanced prostate cancer disease progression can help formulate scientific and standardized treatment plans and strategies for advanced prostate cancer disease progression. Intervention measures provide evidence to improve the quality of life and survival rate of patients. Based on the existing research reports at home and abroad, I reviewed the risk factors related to the progression of advanced prostate cancer.

Intratumoral Restoration of miR-137 Plus Cholesterol Favors Homeostasis of the miR-137/Coactivator p160/AR Axis and Negatively Modulates Tumor Progression in Advanced Prostate Cancer.

MicroRNAs (miRNAs) have gained a prominent role as biomarkers in prostate cancer (PCa). Our study aimed to evaluate the potential suppressive effect of miR-137 in a model of advanced PCa with and without diet-induced hypercholesterolemia. In vitro, PC-3 cells were treated with 50 pmol of mimic miR-137 for 24 h, and gene and protein expression levels of SRC-1, SRC-2, SRC-3, and AR were evaluated by qPCR and immunofluorescence. We also assessed migration rate, invasion, colony-forming ability, and flow cytometry assays (apoptosis and cell cycle) after 24 h of miRNA treatment. For in vivo experiments, 16 male NOD/SCID mice were used to evaluate the effect of restoring miR-137 expression together with cholesterol. The animals were fed a standard (SD) or hypercholesterolemic (HCOL) diet for 21 days. After this, we xenografted PC-3 LUC-MC6 cells into their subcutaneous tissue. Tumor volume and bioluminescence intensity were measured weekly. After the tumors reached 50 mm3, we started intratumor treatments with a miR-137 mimic, at a dose of 6 μg weekly for four weeks. Ultimately, the animals were killed, and the xenografts were resected and analyzed for gene and protein expression. The animals' serum was collected to evaluate the lipid profile. The in vitro results showed that miR-137 could inhibit the transcription and translation of the p160 family, SRC-1, SRC-2, and SRC-3, and indirectly reduce the expression of AR. After these analyses, it was determined that increased miR-137 inhibits cell migration and invasion and impacts reduced proliferation and increased apoptosis rates. The in vivo results demonstrated that tumor growth was arrested after the intratumoral restoration of miR-137, and proliferation levels were reduced in the SD and HCOL groups. Interestingly, the tumor growth retention response was more significant in the HCOL group. We conclude that miR-137 is a potential therapeutic miRNA that, in association with androgen precursors, can restore and reinstate the AR-mediated axis of transcription and transactivation of androgenic pathway homeostasis. Further studies involving the miR-137/coregulator/AR/cholesterol axis should be conducted to evaluate this miR in a clinical context.

Dynamics of antioxidant heme oxygenase-1 and pro-oxidant p66Shc in promoting advanced prostate cancer progression.

The castration-resistant (CR) prostate cancer (PCa) is lethal and is the second leading cause of cancer-related deaths in U.S. males. To develop effective treatments toward CR PCa, we investigated reactive oxygen species (ROS) signaling pathway for its role involving in CR PCa progression. ROS can regulate both cell growth and apoptosis: a moderate increase of ROS promotes proliferation; its substantial rise results in cell death. p66Shc protein can increase oxidant species production and its elevated level is associated with the androgen-independent (AI) phenotype of CR PCa cells; while heme oxygenase-1 (HO-1) is an antioxidant enzyme and elevated in a sub-group of metastatic PCa cells. In this study, our data revealed that HO-1 and p66Shc protein levels are co-elevated in various AI PCa cell lines as well as p66Shc cDNA-transfected cells. Knockdown and/or inhibition of either p66Shc or HO-1 protein leads to reduced tumorigenicity as well as a reduction of counterpart protein. Knockdown of HO-1 alone results in increased ROS levels, nucleotide and protein oxidation and induction of cell death. Together, our data indicate that elevated HO-1 protein levels protect PCa cells from otherwise apoptotic conditions induced by aberrant p66Shc/ROS production, which thereby promotes PCa progression to the CR phenotype. p66Shc and HO-1 can serve as functional targets for treating CR PCa.

RNF8 up-regulates AR/ARV7 action to contribute to advanced prostate cancer progression

Androgen receptor (AR) signaling drives prostate cancer (PC) progression. Androgen deprivation therapy (ADT) is temporally effective, whereas drug resistance inevitably develops. Abnormal expression of AR/ARV7 (the most common AR splicing variant) is critical for endocrine resistance, while the detailed mechanism is still elusive. In this study, bioinformatics and immunohistochemical analyses demonstrate that RNF8 is high expressed in PC and castration-resistant PC (CRPC) samples and the expression of RNF8 is positively correlated with the Gleason score. The high expression of RNF8 in PCs predicts a poor prognosis. These results provide a potential function of RNF8 in PC progression. Furthermore, the mRNA expression of RNF8 is positively correlated with that of AR in PC. Mechanistically, we find that RNF8 upregulates c-Myc-induced AR transcription via altering histone modifications at the c-Myc binding site within the AR gene. RNF8 also acts as a co-activator of AR, promoting the recruitment of AR/ARV7 to the KLK3 (PSA) promoter, where RNF8 modulates histone modifications. These functions of RNF8 are dependent on its E3 ligase activity. RNF8 knockdown further reduces AR transactivation and PSA expression in CRPC cells with enzalutamide treatment. RNF8 depletion restrains cell proliferation and alleviates enzalutamide resistance in CRPC cells. Our findings indicate that RNF8 may be a potential therapeutic target for endocrine resistance in PC.

Natural Products for the Management of Castration-Resistant Prostate Cancer: Special Focus on Nanoparticles Based Studies.

Prostate cancer is the most common type of cancer among men and the second most frequent cause of cancer-related mortality around the world. The progression of advanced prostate cancer to castration-resistant prostate cancer (CRPC) plays a major role in disease-associated morbidity and mortality, posing a significant therapeutic challenge. Resistance has been associated with the activation of androgen receptors via several mechanisms, including alternative dehydroepiandrosterone biosynthetic pathways, other androgen receptor activator molecules, oncogenes, and carcinogenic signaling pathways. Tumor microenvironment plays a critical role not only in the cancer progression but also in the drug resistance. Numerous natural products have shown major potential against particular or multiple resistance pathways as shown by in vitro and in vivo studies. However, their efficacy in clinical trials has been undermined by their unfavorable pharmacological properties (hydrophobic molecules, instability, low pharmacokinetic profile, poor water solubility, and high excretion rate). Nanoparticle formulations can provide a way out of the stalemate, employing targeted drug delivery, improved pharmacokinetic drug profile, and transportation of diagnostic and therapeutic agents via otherwise impermeable biological barriers. This review compiles the available evidence regarding the use of natural products for the management of CRPC with a focus on nanoparticle formulations. PubMed and Google Scholar search engines were used for preclinical studies, while ClinicalTrials.gov and PubMed were searched for clinical studies. The results of our study suggest the efficacy of natural compounds such as curcumin, resveratrol, apigenin, quercetin, fisetin, luteolin, kaempferol, genistein, berberine, ursolic acid, eugenol, gingerol, and ellagic acid against several mechanisms leading to castration resistance in preclinical studies, but fail to set the disease under control in clinical studies. Nanoparticle formulations of curcumin and quercetin seem to increase their potential in clinical settings. Using nanoparticles based on betulinic acid, capsaicin, sintokamide A, niphatenones A and B, as well as atraric acid seems promising but needs to be verified with preclinical and clinical studies.

MP33-06 MACROPHAGE INHIBITORY CYTOKINE-1 INDUCED BY A HIGH-FAT DIET PROMOTES PROSTATE CANCER PROGRESSION BY STIMULATING TUMOR-PROMOTING CYTOKINE PRODUCTION FROM TUMOR STROMAL CELLS

You have accessJournal of UrologyProstate Cancer: Basic Research & Pathophysiology I (MP33)1 Sep 2021MP33-06 MACROPHAGE INHIBITORY CYTOKINE-1 INDUCED BY A HIGH-FAT DIET PROMOTES PROSTATE CANCER PROGRESSION BY STIMULATING TUMOR-PROMOTING CYTOKINE PRODUCTION FROM TUMOR STROMAL CELLS Mingguo Huang, Shintaro Narita, Atsushi Koizumi, Taketoshi Nara, Kazuyuki Numakura, and Tomonori Habuchi Mingguo HuangMingguo Huang More articles by this author , Shintaro NaritaShintaro Narita More articles by this author , Atsushi KoizumiAtsushi Koizumi More articles by this author , Taketoshi NaraTaketoshi Nara More articles by this author , Kazuyuki NumakuraKazuyuki Numakura More articles by this author , and Tomonori HabuchiTomonori Habuchi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002042.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Recent studies have indicated that a high-fat diet (HFD) and/or HFD-induced obesity may influence prostate cancer (PCa) progression, but the role of HFD in PCa microenvironment is unclear. This study aimed to delineate the molecular mechanisms of PCa progression under HFD milieus and define the stromal microenvironment focusing on macrophage inhibitory cytokine-1 (MIC-1) activation. METHODS: We investigated the effects of HFD on PCa stromal microenvironment and MIC-1 signaling activation using PC-3M-luc-C6 PCa model mice fed with HFD or control diet. Further, we explored the effect of periprostatic adipocytes derived from primary PCa patients on activation and cytokine secretion of prostate stromal fibroblasts. Expression patterns and roles of MIC-1 signaling on human PCa stroma activation and progression were also investigated. RESULTS: HFD stimulated PCa cell growth and invasion as a result of upregulated MIC-1 signaling and subsequently increased the secretion of interleukin (IL)-8 and IL-6 from prostate stromal fibroblasts in PC-3M-luc-C6 PCa mouse model. In addition, periprostatic adipocytes directly stimulated MIC-1 production from PC-3 cells and IL-8 secretion in prostate stromal fibroblasts through the upregulation of adipose lipolysis and free fatty acid release. The increased serum MIC-1 was significantly correlated with human PCa stroma activation, high serum IL-8, IL-6, and lipase activity, advanced PCa progression, and high body mass index of the patients. Glial-derived neurotrophic factor receptor α-like (GFRAL), a specific receptor of MIC-1, was highly expressed in both cytoplasm and membrane of PCa cells and surrounding stromal fibroblasts, and the expression level was decreased by androgen deprivation therapy and chemotherapy. CONCLUSIONS: HFD-mediated activation of the PCa stromal microenvironment through metabolically upregulated MIC-1 signaling by increased available free fatty acids may be a critical mechanism of HFD and/or obesity-induced PCa progression. Source of Funding: This work was supported by the Japan Society for the Promotion of Science (JSPS, Grant No.: 16H02679, 16K10992, 19K09663) and AMED-CREST, Japan Agency for Medical Research and Development (AMED) © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e608-e608 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mingguo Huang More articles by this author Shintaro Narita More articles by this author Atsushi Koizumi More articles by this author Taketoshi Nara More articles by this author Kazuyuki Numakura More articles by this author Tomonori Habuchi More articles by this author Expand All Advertisement Loading ...

Macrophage inhibitory cytokine-1 induced by a high-fat diet promotes prostate cancer progression by stimulating tumor-promoting cytokine production from tumor stromal cells.

BackgroundRecent studies have indicated that a high‐fat diet (HFD) and/or HFD‐induced obesity may influence prostate cancer (PCa) progression, but the role of HFD in PCa microenvironment is unclear. This study aimed to delineate the molecular mechanisms of PCa progression under HFD milieus and define the stromal microenvironment focusing on macrophage inhibitory cytokine‐1 (MIC‐1) activation.MethodsWe investigated the effects of HFD on PCa stromal microenvironment and MIC‐1 signaling activation using PC‐3M‐luc‐C6 PCa model mice fed with HFD or control diet. Further, we explored the effect of periprostatic adipocytes derived from primary PCa patients on activation and cytokine secretion of prostate stromal fibroblasts. Expression patterns and roles of MIC‐1 signaling on human PCa stroma activation and progression were also investigated.ResultsHFD stimulated PCa cell growth and invasion as a result of upregulated MIC‐1 signaling and subsequently increased the secretion of interleukin (IL)‐8 and IL‐6 from prostate stromal fibroblasts in PC‐3M‐luc‐C6 PCa mouse model. In addition, periprostatic adipocytes directly stimulated MIC‐1 production from PC‐3 cells and IL‐8 secretion in prostate stromal fibroblasts through the upregulation of adipose lipolysis and free fatty acid release. The increased serum MIC‐1 was significantly correlated with human PCa stroma activation, high serum IL‐8, IL‐6, and lipase activity, advanced PCa progression, and high body mass index of the patients. Glial‐derived neurotrophic factor receptor α‐like (GFRAL), a specific receptor of MIC‐1, was highly expressed in both cytoplasm and membrane of PCa cells and surrounding stromal fibroblasts, and the expression level was decreased by androgen deprivation therapy and chemotherapy.ConclusionHFD‐mediated activation of the PCa stromal microenvironment through metabolically upregulated MIC‐1 signaling by increased available free fatty acids may be a critical mechanism of HFD and/or obesity‐induced PCa progression.

Discovery of JNJ-63576253: A Clinical Stage Androgen Receptor Antagonist for F877L Mutant and Wild-Type Castration-Resistant Prostate Cancer (mCRPC).

Persistent androgen receptor (AR) activation drives therapeutic resistance to second-generation AR pathway inhibitors and contributes to the progression of advanced prostate cancer. One resistance mechanism is point mutations in the ligand binding domain of AR that can transform antagonists into agonists. The AR F877L mutation, identified in patients treated with enzalutamide or apalutamide, confers resistance to both enzalutamide and apalutamide. Compound 4 (JNJ-pan-AR) was identified as a pan-AR antagonist with potent activity against wild-type and clinically relevant AR mutations including F877L. Metabolite identification studies revealed a latent bioactivation pathway associated with 4. Subsequent lead optimization of 4 led to amelioration of this pathway and nomination of 5 (JNJ-63576253) as a clinical stage, next-generation AR antagonist for the treatment of castration-resistant prostate cancer (CRPC).

Aspergillus fumigatus-derived demethoxyfumitremorgin C inhibits proliferation of PC3 human prostate cancer cells through p53/p21-dependent G1 arrest and apoptosis induction

Human prostate cancer is the second most frequently diagnosed cancer worldwide, and its incidence rate continues to increase. Advanced prostate cancer is more difficult to treat than early forms due to its chemotherapy resistance. There is need for more effective agents that can inhibit the progression of advanced prostate cancer. Demethoxyfumitremorgin C (DMFTC) was isolated from the fermentation extract of the marine fungus Aspergillus fumigatus. Antiproliferative activity of DMFTC against human prostate cancer PC3 cells was examined through cell cycle analysis by flow cytometry, the fluorescent nuclear imaging analysis with propidium iodide (PI), and proteins expression related to cell cycle arrest and apoptosis were investigated via Western blotting. DMFTC inhibited PC3 cells growth through G1 phase cell cycle arrest and apoptosis induction. It activated the tumor suppressor p53 and the Cdk inhibitor p21, which regulate the cell progression into the G1 phase. Additionally, PI-positive late apoptotic non-viable cells were increased and the expression levels of the G1-positive downstream regulators cyclin D, cyclin E, Cdk2, and Cdk4 were decreased by DMFTC treatment. These results suggest that DMFTC induces G1 arrest and apoptosis induction through regulation of p53/p21-dependent cyclin-Cdk complexes, and it may be a useful therapeutic agent for the treatment of human advanced prostate cancer.

The PTEN Conundrum: How to Target PTEN-Deficient Prostate Cancer.

Loss of the tumor suppressor phosphatase and tensin homologue deleted on chromosome 10 (PTEN), which negatively regulates the PI3K–AKT–mTOR pathway, is strongly linked to advanced prostate cancer progression and poor clinical outcome. Accordingly, several therapeutic approaches are currently being explored to combat PTEN-deficient tumors. These include classical inhibition of the PI3K–AKT–mTOR signaling network, as well as new approaches that restore PTEN function, or target PTEN regulation of chromosome stability, DNA damage repair and the tumor microenvironment. While targeting PTEN-deficient prostate cancer remains a clinical challenge, new advances in the field of precision medicine indicate that PTEN loss provides a valuable biomarker to stratify prostate cancer patients for treatments, which may improve overall outcome. Here, we discuss the clinical implications of PTEN loss in the management of prostate cancer and review recent therapeutic advances in targeting PTEN-deficient prostate cancer. Deepening our understanding of how PTEN loss contributes to prostate cancer growth and therapeutic resistance will inform the design of future clinical studies and precision-medicine strategies that will ultimately improve patient care.

Abstract 3520: Immunogenomic landscape of grade group 5 prostate cancer predicts risk of lethal outcomes and may inform treatment response

Abstract Introduction Prognostic and therapeutic implications of the immunogenomic landscape in poorly differentiated Grade Group 5 (GG5) prostate cancer (PCa) remains largely unknown. While novel treatment strategies including immuno-radiotherapy have been hypothesized to attenuate disease progression in advanced PCa, limited data exist to show underlying mechanisms related to immunogenomcis and its role in the management of GG5 PCa. Method This retrospective analysis includes 822 PCa patients who underwent radical prostatectomy (RP) with pathologic GG5 disease. Immunogenomic interaction between the immune content score (ICS) and Decipher score was used to predict the metastasis and Prostate cancer specific mortality (PCSM). Immunogenomic interaction categories were used to assess patient response to radiation therapy, measured by the PORTOS score. Additionally, 135 biopsy based tumor samples were also used to validate the immunogenomic correlation between ICS and Decipher as well as the association with PORTOS score. A Kruskal-Wallis test was used to compare median scores whereas methods of survival analysis were used for time dependent endpoints. Principal component analysis (PCA) was used to show sample clustering based on PORTOS score. Results Among GG5 patients 64.8% had high Decipher risk score (> 0.60) whereas 35.5% had low-average risk score (≤ 0.60). When comparing Decipher risk categories with ICS, a linear association was observed with the highest ICS quartile showing the highest Decipher score (Spearman's correlation 0.23, p < 2.4e−11). In a multivariable model, high Decipher score was associated with risk metastasis (HR = 1.63, 95% CI: 1.12 - 2.37, p = 0.01) and PCSM (HR = 1.61, 95% CI: 0.93 – 2.78, p = 0.08) whereas high ICS did not show significant effect on lethal outcomes. However, in the interaction model, effect of decipher on lethal outcomes was augmented in relation with higher ICS. Patients with ICSHigh and DecipherHigh showed significantly higher risk of metastasis (HR = 3.29, 95% CI: 1.53 - 7.07, p = 0.002) and PCSM (HR = 4.15, 95% CI: 1.55 - 11.0, p = 0.004). Additionally, ICSHigh and DecipherHigh also showed higher PORTOS score compared to those with ICSLow and DecipherLow (p < 2.2e−16). Similar to RP cases, in the validation biopsy data Decipher score and ICS were associated (p = 0.01). Likewise, the association of immunogenomic categories with PORTOS score was also consistent in the validation dataset (p = 0.0002). PCA in both RP and validation data using other T cells (i.e. CD4+, CD8+ and Treg) along with ICS, showed separation of high and low PORTOS score categories in relation to immune cells. Conclusions The immunogenomic landscape of GG5 disease has major prognostic and therapeutic implications in aggressive PCa. Immunogenomic interaction between immune content and genomic risk classifiers can be used to identify subsets of patients who are at increased risk of metastasis and PCSM, and may have enhanced response to radiotherapy. Citation Format: Kosj Yamoah, Shivanshu Awasthi, Brandon Mahal, Shuang G. Zhao, Julieta Abraham-Miranda, Travis A. Gerke, Elai Davicioni, Robert J. Rounbehler, Anders E. Berglund, Daniel G. Grass, Jong Y. Park, Julio M. Pow-Sang, Daniel Fernandez, Rohit K. Jain, Edward M. Schaeffer, Stephen Freedland, Daniel E. Spratt, Robert B. Den, Manish Kohli, Timothy R. Rebbeck, Felix Y. Fang. Immunogenomic landscape of grade group 5 prostate cancer predicts risk of lethal outcomes and may inform treatment response [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3520.

BRD4 Regulates Metastatic Potential of Castration-Resistant Prostate Cancer through AHNAK.

The inevitable progression of advanced prostate cancer to castration resistance, and ultimately to lethal metastatic disease, depends on primary or acquired resistance to conventional androgen deprivation therapy (ADT) and accumulated resistance strategies to evade androgen receptor (AR) suppression. In prostate cancer cells, AR adaptations that arise in response to ADT are not singular, but diverse, and include gene amplification, mutation, and even complete loss of receptor expression. Collectively, each of these AR adaptations contributes to a complex, heterogeneous, ADT-resistant tumor. Here, we examined prostate cancer cell lines that model common castration-resistant prostate cancer (CRPC) subtypes, each with different AR composition, and focused on novel regulators of tumor progression, the Bromodomain and Extraterminal (BET) family of proteins. We found that BRD4 regulates cell migration across all models of CRPC, regardless of aggressiveness and AR status, whereas BRD2 and BRD3 only regulate migration and invasion in less aggressive models that retain AR expression or signaling. BRD4, a coregulator of gene transcription, controls migration and invasion through transcription of AHNAK, a large scaffolding protein linked to promotion of metastasis in a diverse set of cancers. Furthermore, treatment of CRPC cell lines with low doses of MZ1, a small-molecule, BRD4-selective degrader, inhibits metastatic potential. Overall, these results reveal a novel BRD4-AHNAK pathway that may be targetable to treat metastatic CRPC (mCRPC). IMPLICATIONS: BRD4 functions as the dominant regulator of CRPC cell migration and invasion through direct transcriptional regulation of AHNAK, which together offer a novel targetable pathway to treat metastatic CRPC.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/8/1627/F1.large.jpg.

Abstract 4285: p66Shc/ROS enhances the progression of androgen-sensitive towards castration-resistant prostate cancer cells

Abstract Purpose and Background: Prostate cancer (PCa) is the second leading cause of cancer-related death in United States men. Androgen deprivation therapy is the standard-of-care treatment for metastatic PCa; most patients eventually relapse and develop castration-resistant (CR) tumors that currently have no effective treatment. Thus, a useful cell model for analysis of the molecular mechanism of PCa progression is required for developing targeted therapies for CR PCa. In this study, we established a PCa cell progressive model in three independent cell lines, of which androgen-independent (AI) cells were derived from respective androgen-sensitive (AS) cells, recapitulating clinical PCa progression. Experimental Methods: AS and AI human prostate adenocarcinoma cell lines LNCaP, MDA PCa2b and VCaP were utilized in this study to demonstrate the molecular and signaling alterations seen in CR PCa. Stable p66Shc cDNA transfected subclones were established from LNCaP-AS cells. The tumorigenicity of AS and AI cells as well as AS PCa cells treated with H2O2 and NAC were evaluated via trypan blue exclusion, transwell migration, clonogenic assays and xenograft mouse models. The signaling profiles including phosphoprotein microarray and immunoblotting were conducted. Results: AI PCa cells have enhanced tumorigenicity, recapitulating the clinical CR phenotype, including AR expression, proliferation and tumorigenicity under androgen-deprived conditions. Further, AI cells exhibit increased ROS levels as well as enhanced signaling of proliferation and survival pathways. We further identified oxidase p66Shc as one of the potential sources of the ROS-mediated phenotypic and cell signaling alterations in AI PCa cells. LNCaP-AI cells and p66Shc subclones have a greater oxidative environment compared to LNCaP-AS cells. Increased ROS via H2O2 enhanced AS cell growth and migration, which was counteracted by antioxidant NAC. Treatment of LNCaP-AS cells with H2O2 resulted in a similar signaling profile to that of LNCaP-AI or p66Shc subclone cells. Further, the ROS-driven alterations of p66Shc subclone cell signaling can be mitigated via p66Shc knockdown or inactive p66Shc mutant. Moreover, LNCaP-AI cells and p66Shc subclones, but not LNCaP-AS cells, develop xenograft tumors with metastatic nodules. Molecular profiling showed that alterations of signaling in LNCaP-AI cells and p66Shc subclones attributed to p66Shc/ROS. Conclusions: We report the establishment of a PCa cell progression model in three commonly used PCa cell lines that replicates clinical PCa progression from the AS to the AI/CR phenotype. Altogether, the data shows ROS produced by p66Shc promotes PCa tumorigenicity and progression to the CR phenotype. Further characterization of the PCa progressive model will aid in the understanding of advanced PCa progression to help in treatment of this lethal disease. Citation Format: Dannah Miller, Matthew Ingersoll, Arpita Chatterjee, Rebecca Oberley-Deegan, Ming-Fong Lin. p66Shc/ROS enhances the progression of androgen-sensitive towards castration-resistant prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4285.

Progress in the study about androgen receptor splicing variants 7 and the drug resistant of prostate cancer

Prostate cancer is an urogenital malignancy which is common in older men. Androgen deprivation therapy is an usual treatment for metastatic prostate cancer significantly inhibiting the progression of advanced prostate cancer via blocking androgen synthesis, or competitive binding to androgen receptors. Nevertheless, most of the patients end up with metastatic castration-resistant prostate cancer (mCRPC) on the account of androgen resistance. It has been shown that androgen receptor splice variant 7 is strongly associated with the development of mCRPC and its drug resistance to androgen receptor signal transduction inhibitors (enzalutamide and abiraterone) in studies of recent years. Key words: Metastatic castration-resistant prostate cancer; Androgen-receptor splice variant 7; Drug resistance to androgen deprivation therapy

ErbB-2 signaling in advanced prostate cancer progression and potential therapy

Currently, prostate cancer (PCa) remains the most commonly diagnosed solid tumor and the second leading cause of cancer-related deaths in US men. Most of these deaths are attributed to the development of castration-resistant (CR) PCa. ErbB-2 and ErbB family members have been demonstrated to contribute to the progression of this lethal disease. In this review, we focus on updating the role of ErbB-2 in advanced PCa progression and its regulation, including its regulation via ligand activation, miRNAs and protein phosphorylation. We also discuss its downstream signaling pathways, including AKT, ERK1/2 and STATs, involved in advanced PCa progression. Additionally, we evaluate the potential of ErbB-2, focusing on its protein hyper-phosphorylation status, as a biomarker for aggressive PCa as well as the effectiveness of ErbB-2 as a target for the treatment of CR PCa via a multitude of approaches, including orally available inhibitors, intratumoral expression of cPAcP, vaccination and immunotherapy.

MicroRNA-126 inhibits proliferation and metastasis in prostate cancer via regulation of ADAM9.

The aberrant expression of microRNAs (miRs) has been identified to serve a crucial role in tumor progression. The present study aimed to evaluate the role of miR-126 in human prostate cancer (PCa). Firstly, miR-126 expression in prostate cancer tissues and cell lines was analyzed. A luciferase reporter assay and a rescue assay were performed, which identified ADAM metalloproteinase domain 9 (ADAM9) as the target gene of miR-126. Subsequently, Kaplan-Meier and log-rank analyses were used to investigate the association between ADAM9 expression and PCa prognosis. The results revealed that miR-126 expression was significantly downregulated in PCa tissues and cell lines. miR-126 overexpression was demonstrated to reduce PCa cell proliferation and metastasis, and to reverse the epithelial-mesenchymal transition process in vitro. In addition, as the target gene of miR-126, the upregulation of ADAM9 reestablished cell functions, including cell proliferation, migration and invasion. Patients with high ADAM9 expression levels exhibited a shorter biochemical recurrence-free survival time. In summary, miR-126 serves a role in the proliferation and metastasis of PCa cells, indicating that miR-126 and ADAM9 may represent potential biomarkers in the progression of advanced PCa, in addition to therapeutic targets.

Transcriptomic features of primary prostate cancer and their prognostic relevance to castration-resistant prostate cancer.

Although various mechanisms of castration-resistant prostate cancer (CRPC) have been discovered, reliable biomarkers for monitoring CRPC progression are lacking. We sought to identify molecules that predict the progression of advanced prostate cancer (AdvPC) into CRPC. The study used primary-site samples (N=45 for next-generation sequencing (NGS); N=243 for real-time polymerase chain reaction) from patients with prostate cancer (PC). Five public databases containing microarray data of AdvPC and CRPC samples were analyzed. The NGS data showed that each progression step in PC associated with distinct gene expression profiles. Androgen receptor (AR) associated with tumorigenesis, advanced progression, and progression into CRPC. Analysis of the paired and unpaired AdvPC and CRPC samples in the NGS cohort showed that 15 genes associated with progression into CRPC. This was validated by cohort-1 and public database analyses. Analysis of the third cohort with AdvPC showed that higher serine peptidase inhibitor, Kazal type 1 (SPINK1) and lower Sp8 transcription factor (SP8) expression associated with progression into CRPC (log-rank test, both P<0.05). Multivariate regression analysis showed that higher SPINK1 (Hazard Ratio (HR)=4.506, 95% confidence intervals (CI)=1.175–17.29, P=0.028) and lower SP8 (HR=0.199, 95% CI=0.063–0.632, P=0.006) expression independently predicted progression into CRPC. Gene network analysis showed that CRPC progression may be mediated through the AR-SPINK1 pathway by a HNF1A-based gene network. Taken together, our results suggest thatSPINK1 and SP8 may be useful for classifying patients with AdvPC who have a higher risk of progressing to CRPC.