Treatment Of PCa Research Articles

Simultaneous Autophagy and Androgen Receptor Inhibition in a Prostate Cancer Xenograft Model

Objective: Abi, when used in conjunction with prednisone, is an established treatment for advanced PCa. Our goal was to explore the level of autophagy induced by Abi treatment, both alone and in combination with the autophagy inhibitor Chl, in a castrated mouse xenograft model. Methods: LNCaP cells were injected into the left and right sides of the back of nude mice that had been previously castrated. Mice were divided into four groups and treated daily with intraperitoneal injections of vehicle (control), Abi (10 mg/kg), Abi (10 mg/kg) combined with Chl (10 mg/kg), or Chl (10 mg/kg), and were monitored for periods of 2 and 3 weeks. Results: A significant reduction in tumor weight was observed in mice treated with the combination therapy, as opposed to those receiving vehicle control, Abi, or Chl alone. Mice receiving Abi + Chl exhibited reduced expression of ATG5, Beclin 1, and LC3 punctuations, along with an increase in P62, as determined by immunofluorescence and WES analysis. AR expression decreased significantly in all treatment groups compared to the control. PSMA expression was highest in the vehicle and combined treatment groups after 3 weeks, with a significant reduction observed with Chl treatment. Conclusions: These findings demonstrate that Abi + Chl treatment lowers autophagy levels and suppresses tumors more effectively than Abi alone.

Identification and validation of diagnostic and prognostic biomarkers in prostate cancer based on WGCNA

BackgroundProstate cancer (PCa) represents a significant health challenge for men, and the advancement of the disease often results in a grave prognosis for patients. Therefore, the identification of biomarkers associated with the diagnosis and prognosis of PCa holds paramount importance in patient health management.MethodsThe datasets pertaining to PCa were retrieved from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was conducted to investigate the modules specifically associated with the diagnosis of PCa. The hub genes were identified using the LASSO regression analysis. The expression levels of these hub genes were further validated by qRT-PCR experiments. Receiver operating characteristic (ROC) curves and nomograms were employed as evaluative measures for assessing the diagnostic value.ResultsThe blue module identified by WGCNA exhibited a strong association with PCa. Six hub genes (SLC14A1, COL4A6, MYOF, FLRT3, KRT15, and LAMB3) were identified by LASSO regression analysis. Further verification confirmed that these six genes were significantly downregulated in tumor tissues and cells. The six hub genes and the nomogram demonstrated substantial diagnostic value, with area under the curve (AUC) values ranging from 0.754 to 0.961. Moreover, patients with low expression levels of these six genes exhibited elevated T/N pathological stage and Gleason score, implying a more advanced disease state. Meanwhile, their progression-free survival (PFS) was observed to be potentially poorer. Finally, a significant association could be observed between the expression of these genes and the dysregulation of immune cells, along with drug sensitivity.ConclusionsIn summary, our study identified six hub genes, namely SLC14A1, COL4A6, MYOF, FLRT3, KRT15, and LAMB3, which can be utilized to establish a diagnostic model for PCa. The discovery may offer potential molecular targets for clinical diagnosis and treatment of PCa.

Salvage local treatment for recurrent prostate cancer after focal therapy: A systematic review and meta-analysis

ObjectivesTo evaluate the role of salvage local treatment in managing recurrent PCa following FT, focusing on oncological and functional outcomes. MethodsA systematic review and meta-analysis were performed following the PRISMA framework. A comprehensive literature search using the PubMed/MEDLINE and EMBASE databases was performed until July 2023. Eligible studies included patients with clinically localised PCa initially treated with FT, who experienced relapse during surveillance and subsequently underwent salvage radical prostatectomy (sRP), salvage external beam radiation therapy (sEBRT) or salvage focal therapy (sFT). The primary endpoint was the biochemical recurrence rate post-salvage treatment. The secondary endpoints were functional outcomes, including urinary incontinence and erectile dysfunction rates. ResultsIn 26 retrospective studies including 990 patients, the overall pooled biochemical recurrence rate postsalvage treatment was 26%. The subgroup analysis revealed a biochemical recurrence rate of 20%, 22%, and 42% after sRP, sEBRT, and sFT, respectively. The overall pooled rate of urinary incontinence was 20%. Salvage FT had the lowest prevalence of urinary incontinence, followed by sRP and sEBRT. The overall pooled rate of erectile dysfunction was 43%. Salvage RP had the highest prevalence of erectile dysfunction, followed by sFT and sEBRT. Substantial heterogeneity was observed among the studies, primarily due to different sample sizes. Meta-regression analysis revealed no to low contributions of salvage treatment modalities, extent of ablation, age, prostatic specific antigen level before salvage treatment, proportion of patients with Gleason score ≥7 at recurrence, and time between the primary and salvage therapies to heterogeneity. ConclusionSalvage local treatment for recurrent PCa after FT is feasible, and it provides acceptable oncological and functional outcomes. Among all treatment modalities, sRP and sEBRT appeared to have the lowest biochemical recurrence rates, whereas sFT was associated with improved functional outcomes.

Prognostic and immunological implications of heterogeneous cell death patterns in prostate cancer

BackgroundProstate cancer is one of the most common cancers in men with a significant proportion of patients developing biochemical recurrence (BCR) after treatment. Programmed cell death (PCD) mechanisms are known to play critical roles in tumor progression and can potentially serve as prognostic and therapeutic biomarkers in PCa. This study aimed to develop a prognostic signature for BCR in PCa using PCD-related genes.Materials and methodsWe conducted an analysis of 19 different modes of PCD to develop a comprehensive model. Bulk transcriptomic, single-cell transcriptomic, genomic, and clinical data were collected from multiple cohorts, including TCGA-PRAD, GSE58812, METABRIC, GSE21653, and GSE193337. We analyzed the expression and mutations of the 19 PCD modes and constructed, evaluated, and validated the model.ResultsTen PCD modes were found to be associated with BCR in PCa, with specific PCD patterns exhibited by various cell components within the tumor microenvironment. Through Lasso Cox regression analysis, we established a Programmed Cell Death Index (PCDI) utilizing an 11-gene signature. High PCDI values were validated in five independent datasets and were found to be associated with an increased risk of BCR in PCa patients. Notably, older age and advanced T and N staging were associated with higher PCDI values. By combining PCDI with T staging, we constructed a nomogram with enhanced predictive performance. Additionally, high PCDI values were significantly correlated with decreased drug sensitivity, including drugs such as Docetaxel and Methotrexate. Patients with lower PCDI values demonstrated higher immunophenoscores (IPS), suggesting a potentially higher response rate to immune therapy. Furthermore, PCDI was associated with immune checkpoint genes and key components of the tumor microenvironment, including macrophages, T cells, and NK cells. Finally, clinical specimens validated the differential expression of PCDI-related PCDRGs at both the gene and protein levels.ConclusionIn conclusion, we developed a novel PCD-based prognostic feature that successfully predicted BCR in PCa patients and provided insights into drug sensitivity and potential response to immune therapy. These findings have significant clinical implications for the treatment of PCa.

Radiation therapy and IRreversible electroporation for intermediate risk prostate cancer (RTIRE)

IntroductionRadiation Therapy and IRreversible Electroporation for Intermediate Risk Prostate Cancer (RTIRE) is a phase II clinical trial testing combination of radiation therapy and irreversible electroporation for intermediate risk prostate cancerBackgroundPCa is the most common non-cutaneous cancer in men and the second leading cause of cancer death in men. PCa treatment is associated with long term side effects including urinary, sexual, and bowel dysfunction. Management of PCa is based on risk stratification to prevent its overtreatment and associated treatment-related toxicity. There is increasing interest in novel treatment strategies, such as focal therapy, to minimize treatment associated morbidity. Focal therapy alone has yet to be included in mainstream guidelines, given ongoing concerns with potentially higher risk of recurrence. We hypothesize combining focal therapy with whole gland, reduced dose radiotherapy will provide acceptable oncologic efficacy with minimal treatment associated morbidity. RTIRE is a phase II single institution, investigator-initiated study combining a local ablative technique though local irreversible electroporation (IRE) with MR guided RT (MRgRT) to treat the entire prostate. The goal is to provide excellent oncologic outcomes and minimize treatment related side effects through leveraging benefits of locally ablative therapy with established radiation treatment techniques.MethodsA total of 42 men with intermediate risk PCa per NCCN guidelines and focal grade group (GG) 2 or 3, Gleason Score (GS) 3 + 4 or GS 4 + 3, cancer in an MRI target will be enrolled. Patients with MRI visible foci of GG2/GG3 will undergo focal therapy with IRE of this lesion. Following successful focal therapy, patients will then undergo a course of reduced dose, whole gland MRgRT with either 32.5 Gy in 5 Fractions or 22 Gy in 2 fractions. The primary objective of the study is to determine safety. Secondary outcomes include evaluation of oncologic efficacy (as measured by the proportion of patients free of clinically significant cancer as defined as > Grade Group 1 at 1-year follow-up biopsy), imaging characteristics of patients pre and post RTIRE, impact on quality of life (QoL), and PSA kinetics.DiscussionCombining IRE with a reduced dose radiotherapy may offer a new treatment paradigm for PCa by both reducing treatment effects of full dose radiotherapy and minimizing the risk of recurrence observed with focal therapy.Trial RegistrationClinicaltrials.gov identifier: NCT05345444. Date of registration: April 25, 2022. Protocol Version: 6.0, July 7, 2023.

Saikosaponin-d mediates FOXG1 to reverse docetaxel resistance in prostate cancer through oxidative phosphorylation

BackgroundProstate cancer (PCa), a prevalent malignancy worldwide, is frequently identified in advanced stages due to the absence of distinctive early symptoms, thereby culminating in the development of chemotherapy-induced drug resistance. Exploring novel resistance mechanisms and identifying new therapeutic agents can facilitate the advancement of more efficacious strategies for PCa treatment. MethodsBioinformatics analysis was employed to investigate the expression of FOXG1 in PCa tissues. Subsequently, qRT-PCR was utilized to validate FOXG1 mRNA expression levels in corresponding PCa cell lines. FOXG1 knockdown was performed, and cell proliferation was assessed using CCK-8 assays, while cell migration and invasion capabilities were evaluated through wound healing and Transwell assays. Western blot and Seahorse analyzer were used to measure oxidative phosphorylation (OXPHOS) levels. Additionally, to explore potential approaches to alleviate PCa drug resistance, this study assessed the impact of biologically active saikosaponin-d (SSd) on PCa malignant progression and resistance by regulating FOXG1 expression. ResultsFOXG1 exhibited high expression in PCa tissues and cell lines. Knockdown of FOXG1 inhibited the proliferation, migration, and invasion of PCa cells, while FOXG1 overexpression had the opposite effect and promoted OXPHOS levels. The addition of an OXPHOS inhibitor prevented this outcome. Finally, SSd was shown to suppress FOXG1 expression and reverse docetaxel resistance in PCa cells through the OXPHOS pathway. ConclusionThis work demonstrated that SSd mediated FOXG1 to reverse malignant progression and docetaxel resistance in PCa through OXPHOS.

A black phosphorus nanosheet-based RNA delivery system for prostate cancer therapy by increasing the expression level of tumor suppressor gene PTEN via CeRNA mechanism

BackgroundProstate cancer (PCa) has a high incidence in men worldwide, and almost all PCa patients progress to the androgen-independent stage which lacks effective treatment measures. PTENP1, a long non-coding RNA, has been shown to suppress tumor growth through the rescuing of PTEN expression via a competitive endogenous RNA (ceRNA) mechanism. However, PTENP1 was limited to be applied in the treatment of PCa for the reason of rapid enzymatic degradation, poor intracellular uptake, and excessively long base sequence to be synthesized. Considering the unique advantages of artificial nanomaterials in drug loading and transport, black phosphorus (BP) nanosheet was employed as a gene-drug carrier in this study.ResultsThe sequence of PTENP1 was adopted as a template which was randomly divided into four segments with a length of about 1000 nucleotide bases to synthesize four different RNA fragments as gene drugs, and loaded onto polyethyleneimine (PEI)-modified BP nanosheets to construct BP-PEI@RNA delivery platforms. The RNAs could be effectively delivered into PC3 cells by BP-PEI nanosheets and elevating PTEN expression by competitive binding microRNAs (miRNAs) which target PTEN mRNA, ultimately exerting anti-tumor effects.ConclusionsTherefore, this study demonstrated that BP-PEI@RNAs is a promising gene therapeutic platform for PCa treatment.Graphical

2391: Longitudinal assessment of the impact of pelvic nodal radiotherapy on lymphopenia in PCa treatment

2391: Longitudinal assessment of the impact of pelvic nodal radiotherapy on lymphopenia in PCa treatment

Development and first-in-human study of PSMA-targeted PET tracers with improved pharmacokinetic properties.

A series of new 68Ga-labeled tracers based on [68Ga]Ga-PSMA-617 were developed to augment the tumor-to-kidney ratio and reduce the activity accumulation in bladder, ultimately minimize radiation toxicity to the urinary system. We introduced quinoline group, phenylalanine and decanoic acid into different tracers to enhance their lipophilicity, strategically limiting their metabolic pathway through the urinary system. Their binding affinity onto LNCaP cells was determined through in vitro saturation assays and competition binding assays. In vivo metabolic study, PET imaging and biodistribution experiment were performed in LNCaP tumor-bearing B-NSG male mice. The most promising tracer was selected for first-in-human study. Four radiotracers were synthesized with radiochemical purity (RCP) > 95% and molar activity in a range of 20.0-25.5GBq/μmol. The binding affinities (Ki) of TWS01, TWS02 to PSMA were in the low nanomolar range (< 10nM), while TWS03 and TWS04 exhibited binding affinities with Ki > 20nM (59.42nM for TWS03 and 37.14nM for TWS04). All radiotracers exhibited high stability in vivo except [68Ga]Ga-TWS03. Micro PET/CT imaging and biodistribution analysis revealed that [68Ga]Ga-TWS02 enabled clear tumor visualization in PET images at 1.5h post-injection, with higher tumor-to-kidney ratio (T/K, 0.93) and tumor-to-muscle ratio (T/M, 107.62) compared with [68Ga]Ga-PSMA-617 (T/K: 0.39, T/M: 15.01) and [68Ga]Ga-PSMA-11 (T/K: 0.15, T/M: 24.00). In first-in-human study, [68Ga]Ga-TWS02 effectively detected PCa-associated lesions including primary and metastatic lesions, with lower accumulation in urinary system, suggesting that [68Ga]Ga-TWS02 might be applied in the detection of bladder invasion, with minimized radiation toxicity to the urinary system. Introduction of quinoline group, phenylalanine and decanoic acid into different tracers can modulate the binding affinity and pharmacokinetics of PSMA in vivo. [68Ga]Ga-TWS02 showed high binding affinity to PSMA, excellent pharmacokinetic properties and clear imaging of PCa-associated lesions, making it a promising radiotracer for the clinical diagnosis of PCa. Moreover, TWS02 with a chelator DOTA could also label 177Lu and 225Ac, which could be used for PCa treatment without significant side effects. The clinical evaluation of this study was registered On October 30, 2021 at https://www.chictr.org.cn/ (No: ChiCTR2100052545).

Development of risk-score model in patients with negative surgical margin after robot-assisted radical prostatectomy

A total of 739 patients underwent RARP as initial treatment for PCa from November 2011 to October 2018. Data on BCR status, clinical and pathological parameters were collected from the clinical records. After excluding cases with neoadjuvant and/or adjuvant therapies, presence of lymph node or distant metastasis, and positive SM, a total of 537 cases were eligible for the final analysis. The median follow-up of experimental cohort was 28.0 (interquartile: 18.0–43.0) months. We identified the presence of International Society of Urological Pathology grade group (ISUP-GG) ≥ 4 (Hazard ratio (HR) 3.20, 95% Confidence Interval (95% CI) 1.70–6.03, P < 0.001), lymphovascular invasion (HR 2.03, 95% CI 1.00–4.12, P = 0.049), perineural invasion (HR 10.7, 95% CI 1.45–79.9, P = 0.020), and maximum tumor diameter (MTD) > 20 mm (HR 1.9, 95% CI 1.01–3.70, P = 0.047) as significant factors of BCR in the multivariate analysis. We further developed a risk model according to these factors. Based on this model, 1-year, 3-year, and 5-year BCR-free survival were 100%, 98.9%, 98.9% in the low-risk group; 99.1%, 94.1%, 86.5% in the intermediate-risk group; 93.9%, 84.6%, 58.1% in the high-risk group. Internal validation using the bootstrap method showed a c-index of 0.742 and an optimism-corrected c-index level of 0.731. External validation was also carried out using an integrated database derived from 3 other independent institutions including a total of 387 patients for the final analysis. External validation showed a c-index of 0.655. In conclusion, we identified risk factors of biochemical failure in patients showing negative surgical margin after RARP and further developed a risk model using these risk factors.

Predicting prostate cancer recurrence: Introducing PCRPS, an advanced online web server

BackgroundProstate cancer (PCa) is one of the leading causes of cancer death in men. About 30% of PCa will develop a biochemical recurrence (BCR) following initial treatment, which significantly contributes to prostate cancer-related deaths. In clinical practice, accurate prediction of PCa recurrence is crucial for making informed treatment decisions. However, the development of reliable models and biomarkers for predicting PCa recurrence remains a challenge. In this study, the aim is to establish an effective and reliable tool for predicting the recurrence of PCa. MethodsWe systematically screened and analyzed potential datasets to predict PCa recurrence. Through quality control analysis, low-quality datasets were removed. Using meta-analysis, differential expression analysis, and feature selection, we identified key genes associated with recurrence. We also evaluated 22 previously published signatures for PCa recurrence prediction. To assess prediction performance, we employed nine machine learning algorithms. We compared the predictive capabilities of models constructed using clinical variables, expression data, and their combinations. Subsequently, we implemented these machine learning models into a user-friendly web server freely accessible to all researchers. ResultsBased on transcriptomic data derived from eight multicenter studies consisting of 733 PCa patients, we screened 23 highly influential genes for predicting prostate cancer recurrence. These genes were used to construct the Prostate Cancer Recurrence Prediction Signature (PCRPS). By comparing with 22 published signatures and four important clinicopathological features, the PCRPS exhibited a robust and significantly improved predictive capability. Among the tested algorithms, Random Forest demonstrated the highest AUC value of 0.72 in predicting PCa recurrence in the testing dataset. To facilitate access and usage of these machine learning models by all researchers and clinicians, we also developed an online web server (https://urology1926.shinyapps.io/PCRPS/) where the PCRPS model can be freely utilized. The tool can also be used to (1) predict the PCa recurrence by clinical information or expression data with high accuracy. (2) provide the possibility of PCa recurrence by nine machine learning algorithms. Furthermore, using the PCRPS scores, we predicted the sensitivity of 22 drugs from GDSC2 and 95 drugs from CTRP2 to the samples. These predictions provide valuable insights into potential drug sensitivities related to the PCRPS score groups. ConclusionOverall, our study provides an attractive tool to further guide the clinical management and individualized treatment for PCa.

Abstract 5834: The GR-LEDGF/p75 transcriptional network promotes therapy cross-resistance in prostate cancer cells

Abstract Prostate cancer (PCa) is the second leading cause of cancer mortality for men in the U.S. Patients who develop advanced PCa ultimately acquire therapy resistance and succumb to the disease. An emerging challenge in the treatment of advanced PCa is the development of therapy cross-resistance, in which molecular pathways promoting resistance to a particular drug or treatment also promote resistance to subsequent treatments. Although the mechanisms driving PCa therapy cross-resistance are not clearly understood, recent studies from our group and others implicate the glucocorticoid receptor (GR), a transcription factor, in resistance to both androgen receptor signaling inhibitors such enzalutamide (ENZ), and taxane drugs such as docetaxel (DTX). Our studies also showed that GR upregulates and interacts with the lens epithelium derived growth factor of 75 kD (LEDGF/p75) in a large panel of PCa cell lines. LEDGF/p75 is a stress transcription co-activator and oncoprotein that promotes cancer cell resistance to DTX and DNA-damaging drugs. GR and LEDGF/p75 are part of a large transcriptional network that include other oncogenic transcription factors linked to cancer chemoresistance such as β-catenin, Menin, MLL, JPO2, and c-Myc. We hypothesized that this transcriptional network plays a role in PCa therapy cross-resistance and could be a promising therapeutic target. We observed by Western blotting (WB) that both GR and LEDGF/p75 proteins are upregulated in ENZ-resistant and DTX-resistant PCa cell lines, and that GR silencing in both contexts abrogated LEDGF/p75 expression. MTT viability assays showed that ENZ-resistant PCa cells also exhibited cross-resistance to DTX. Bioinformatics studies, using publicly available RNA-seq datasets, identified overlapping differentially expressed genes (DEGs) between ENZ-resistant and DTX-resistant PCa cells. Individual silencing of GR and LEDGF/p75 in two DTX-resistant PCa cell lines followed by RNA-seq analysis also identified an overlap between DEGs regulated by GR and LEDGF/p75 with DEGs associated with both ENZ and DTX resistance in PCa. GSEA analysis of DEGs targeted by both GR and LEDGF/p75 in DTX-resistant PCa cells revealed enriched pathways associated with stress responses, androgen responses, and regulation of cell death and cell cycle. Further, we initiated studies to evaluate the efficacy of small molecule inhibitors targeting multiple components of the GR-LEDGF/p75 transcriptional network in sensitizing therapy-resistant PCa cells to DTX and ENZ. In conclusion, our results implicate the GR-LEDGF/p75 axis in promoting resistance to both ENZ and DTX in PCa cells. Further mining of RNA-seq data will identify potential molecular targets associated with PCa therapy cross-resistance, leading to the design of novel therapeutic strategies to attenuate this resistance. Citation Format: Pedro T. Ochoa, Evelyn S. Sanchez-Hernandez, Kai Wen Cheng, Isaac Kremsky, Charles Wang, Carlos A. Casiano. The GR-LEDGF/p75 transcriptional network promotes therapy cross-resistance in 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 5834.

Abstract 4150: Development of a three-dimensional spatialomics map of lethal prostate cancer driven by clinical imaging

Abstract Prostate adenocarcinoma (PCa) is the most common malignancy and the second leading cause of cancer-related mortality in United States men. Following treatment for localized PCa, up to 50% of these men can experience disease recurrence, with subsequent metastasis and death. This indicates that there is suboptimal identification of lethal PCa at the time of diagnosis, despite advancements in imaging, genomics, and biomarkers. To improve the noninvasive diagnosis of lethal PCa at initial diagnosis, we have developed a novel magnetic resonance imaging (MRI) method, diffusion basis spectrum imaging (DBSI), that noninvasively measures cancer, stromal, and immune cell contributions to the prostate tumor microenvironment (TME). To validate DBSI for PCa, we have applied novel technologies to matched prostatectomy specimens that include (i) fully automated tissue section processing with serial 2-photon tomographic (STP) imaging of the sections to generate 3D volumetric structural maps of the tumor tissue and (ii) multiplex MALDI mass spectrometry imaging of untargeted glycans and extracellular matrix (ECM) peptides and of proteins targeted with novel photocleavable-mass-tagged antibodies (MALDI-IHC) to spatially resolve hundreds of biomolecules from the TME. To establish the feasibility of this approach, we recruited a patient with an unusually aggressive prostate cancer consisting of Gleason 5+4 acinar adenocarcinoma histology with intraductal growth that was locally invasive and lymph node positive at prostatectomy (stage T3bN1). This patient also had the unusual finding of low activity on prostate specific membrane antigen positron emission tomography (PSMA-PET). Following gross sectioning of the prostate with MRI-guided 3D printed molds to co-register clinical DBSI with histology, a 5-mm thick tissue cross-section containing tumor and normal prostate was imaged with high resolution ex vivo DBSI followed by 3D structural mapping with STP imaging. Selected slides in the 3D stack were subject to multiplexed MALDI imaging to identify relationships between cellular and molecular heterogeneity with tumor structure identified with DBSI and STP imaging. We discovered unique structural differences in the prostate tumor compared with the surrounding stroma based upon collagen and glycan modifications to the ECM that were recapitulated with second harmonic maps of collagen from STP imaging as well as stromal maps generated from DBSI imaging. Additional novel protein and glycan ECM components were expressed in this tumor known to be associated with poor patient outcomes. Together, these data represent the first evidence successfully linking noninvasive in vivo clinical imaging and de novo spatialomics technologies with potential to improve PCa diagnostics. This advanced imaging workflow can be applied to any tissue type, underscoring its relevance to translational cancer research. Citation Format: Joseph E. Ippolito, David H. Ballard, Karla Bergeron, Ritesh Chidambaram, Anusha Elumalai, Tyler J. Fraum, Huaping Jing, Peter Kamelin, Eric H. Kim, Catherine Kita, Aleksandra Klim, Anthony Knesis, Mark Lim, José Marcio Luna, Hani Nakhoul, Timothy Ragan, Kenneth J. Rothschild, Sheng-Kwei Song, Kainen Utt, Cody Weimholt, Gargey Yagnik, Elijah Yew, Peggi M. Angel, Richard R. Drake. Development of a three-dimensional spatialomics map of lethal prostate cancer driven by clinical imaging [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 4150.

Abstract 1678: Docetaxel induces Rac1 and Cdc42 Rho GTPase activation in prostate cancer cells

Abstract Prostate cancer (PCa) is a major health burden that affects the quality of life of men worldwide. In the United States, PCa is the second leading cause of mortality among cancers that affect men. Treatment of advanced PCa aims to suppress androgen signaling and proliferation in cancer cells using anti-androgens and chemotherapy. However, the development of drug resistance is a major limitation to curing advanced prostate cancer and strategies to block mechanisms of therapy resistance would enhance treatment efficacy and potentially improve patient prognosis. Cdc42 and Rac1, members of the family of Rho GTPases, have been associated with the progression of different types of hormone-associated cancer, such as breast, ovary, and prostate, among others. The current study was designed to evaluate the role of Cdc42 and Rac1 in chemoresistant prostate cancer cells, including under castration-resistant and androgen-independent conditions. We did not observe significant differences in active (Rac-GTP) or total Rac1 levels in chemoresistant compared to parental PC3 or DU145 cells; similar findings were observed for Ccd42. Treatment of drug-naïve cells with a sublethal dose of docetaxel (10uM) induced gradual increases in Rac1-GTP up to 30 minutes in 22rv1, 60 minutes in LNCaP and DU145, and 24 hours in PC3 cells. Cdc42-GTP levels also increased with subacute docetaxel treatment up to 24 hours in 22rv1 and DU145. Chemoresistant 22rv1, PC3, and DU145 exhibited similar sensitivity to Rac1 and Ccd42 inhibitors including MB1-167, MBQ-168, EHop-097, with an IC50 of about 1uM for each compound and line. Ongoing studies are evaluating the role of these Rho-GTPases in 3-dimensional growth and survival. Citation Format: Andrea Paola López González, Jessica Colón González, María C. Santa María Fuentes, Surangani Dharmawardhane, Carlos J. Diaz Osterman. Docetaxel induces Rac1 and Cdc42 Rho GTPase activation in 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 1678.

Abstract 6045: Development and characterization of ATC-324: An AUTOTAC-based androgen receptor degrader for prostate cancer treatment

Abstract Prostate cancer (PCa) progression is largely driven by the androgen receptor (AR), making it a prime target for therapy. However, therapy resistance often arises due to AR mutations and splice variants, such as AR-v7. AUTOTAC (AUTOphagy-TArgeting Chimera) is a novel protein degradation platform that utilizes the autophagy-lysosomal pathway to selectively degrade disease-causing proteins. In this study, we characterize ATC-324, an AUTOTAC-based AR degrader designed for the treatment of PCa. ATC-324 comprises enzalutamide linked to YT 6-2, a small molecule activator of the autophagy receptor p62/SQSTM1. ATC-324 induces the formation of the AR/p62 complex while activating autophagic flux, leading to the autophagy-lysosomal degradation of AR. To characterize ATC-324, we employed various AR-dependent, AR-null, and enzalutamide-resistant PCa cell lines. Given that bone metastasis is a major clinical complication of castrate-resistant PCa associated with greater morbidity and mortality, we utilized the bone-in-culture array (BICA) assay, an ex vivo bones culture model, to investigate the impact of ATC-324 on PCa cell survival and growth in the bone microenvironment. We demonstrated that ATC-324 effectively degrades wild-type, mutant, and splice variants of AR. In addition, ATC-324 induces AR-dependent apoptosis and cytotoxicity. Importantly, ATC-324 maintains its potency in enzalutamide-resistant PCa cells. Utilizing the BICA assay, we showed that ATC-324 exhibits cytotoxicity against 22Rv1 bone micrometastases at even lower concentrations than in 2D cell culture. In conclusion, our study demonstrates the successful development and characterization of ATC-324 as a potent and selective degrader of various forms of AR. Furthermore, its effectiveness against enzalutamide-resistant cells indicates its capability to overcome therapy resistance. The observed cytotoxicity against bone micrometastases suggests a therapeutic potential for combating bone metastasis, a major complication of castration-resistant PCa. Our study underscores the potential of the AUTOTAC platform to selectively degrade disease-causing proteins Citation Format: Tri Pham, Tae Hyun Bae, Ki Woon Sung, Abdo Najy, Alaleh Zamiri, Hyejeong Jang, Su Ran Mun, Seongho Kim, Dongping Shi, Steven Kregel, Elizabeth Heath, Michael Cher, Yong Tae Kwon, Hyeong-Reh Kim. Development and characterization of ATC-324: An AUTOTAC-based androgen receptor degrader for prostate cancer treatment [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 6045.

Abstract 3690: Monitoring prostate specific membrane antigen or androgen receptor expression on circulating stromal cells in advanced prostate cancer patients and their correlation with patient response

Abstract Background: Metastatic Prostate cancer (mPCa) mortality rates are high despite numerous treatment options against various mechanisms of action, including targeted therapies, i.e. prostate specific membrane antigen (PSMA)-targeted therapy (Pluvicto) or anti-androgen receptor (AR) (Enzulamide, Biculamide). Further, tumor biomarkers (i.e. PSMA and AR) can change over time and with resistance mechanisms that develop after treatments. This suggests that primary biopsies may not represent later PCa tumors necessitating a way to identify patients that may respond to later line therapies. Blood based biopsies can be used to monitor PCa treatment, which can include circulating tumor cells (CTCs) and the newly discovered cancer associated macrophage like cells (CAMLs), a cancer specific circulating phagocytic stromal cells. Interestingly, while PSMA &amp; AR have been identified in CTCs, they have not been evaluated in CAMLs, nor have PSMA &amp; AR expressions in CTCs &amp; CAMLs been evaluated in anti-AR therapy settings. We measured CAMLs &amp; CTCs in mPCa to evaluate their PSMA &amp; AR expression, including in patients treated with anti-AR therapy. Methods: We evaluated CAMLs &amp; CTCs in a multi-institutional prospective pilot study using n=30 mPCa patients with progressive disease, prior to starting a new line of therapy (T0). Whole peripheral blood (7.5mL) was filtered for CAMLs &amp; CTCs and stained for PSMA (n=15) &amp; AR (n=15). In addition, 15 patients were treated with anti-AR therapy as standard of care and responses by PET/CT were compared against AR expression. When possible, follow up samples (T1) were also procured. Results: CTCs were identified in 16% (n=5/30) of patients and CAMLs were identified in 96% (n=29/30), with 53% of patients having hyperengorged CAMLs ≥50 μm (n=16/30). CTCs in patients were not statistically significant for worse outcomes PFS HR= 0.1748, p=0.546 nor OS (HR= 1.303, p=0.865), nor were CAMLs prognostic for PFS or OS. However, patients with ≥50 μm CAMLs did have significantly worse PFS (HR= 5.9, CI95% 2.2-16.3, p=0.001) and worse OS (HR= 3.1, CI95% 1.3-7.1, p=0.016). Further, PSMA CAML/CTC expression was high in 60% (n=9/15) of patients and AR CAML/CTC expression was high in 53% (n=8/15). Of the n=15 patients who received anti-AR therapy after T0, high AR expressing CAMLs/CTCs (n=8/15) had a ~250% better mPFS of 10.3 months (mons) (progressing at 2.2-32.6 mons) vs low AR CAMLs/CTCs mPFS of 4 mons (progressing at 0.2-7.2 mons). Additional mOS analysis from T1 samples and 2-year survival is ongoing. Conclusion: We utilized liquid biopsies to monitor the expression of two common cell surface receptors (PSMA &amp; AR) in CAMLs and CTCs in mPCa. Further, in a small subset of patients treated with AR therapy, high AR CTC/CAML expression appeared to correlate with better response rates, though larger prospective studies are needed. Citation Format: Dimpal M. Kasabwala, Raymond C. Bergan, R. Katherine Alpaugh, Daniel C. Danila, Tuan L. Chuang, Brenda Y. Hurtado, Daniel L. Adams. Monitoring prostate specific membrane antigen or androgen receptor expression on circulating stromal cells in advanced prostate cancer patients and their correlation with patient response [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 3690.

Abstract 1475: Investigating the carcinogenic effects and the mechanism of cadmium exposure on WPMY-1 prostate myofibroblast cell line

Abstract Prostate cancer (PCa) is the second most common cancer among males with an incidence rate of PCa is 288,300 new cases annually. Risk factors include age, genetics, and lifestyle, but the underlying stimuli remain largely uncertain. One potential emerging cause of PCa is exposure to metal carcinogens as cadmium (Cd) which is now classified as a group I human carcinogen. Chronic exposure to Cd on epithelial cells has been extensively shown to induce carcinogenesis, making it a likely contributor to PCa development. In this study, we expand this information by examining how chronic Cd exposure affects prostate-derived myofibroblast (WPMY-1) cells transforming into a cancer-associated fibroblast like phenotype. To study the transformation, WPMY-1 cells were treated with 500nM of Cd for a period of 11 months establishing the WPMY-1 Cd model. Fibroblasts are a crucial tumor microenvironment (TME) component and potentially contribute to PCa progression when transformed and activated into cancer-associated fibroblasts (CAFs). To begin, we used an MTT assay to measure the effect of Cd toxicity on normal prostate myofibroblasts versus WPMY-1 Cd. The data showed that 10µM Cd solution was toxic to WPMY-1 cells, but WPMY-Cd cells depicted high cell viability at 50 µM dose, conferring to chronic Cd exposure improved resiliency to Cd toxicity. We analyzed the expression of CAF-specific markers in WPMY-Cd cells, such as vimentin, FAP, α-SMA, and PDGFR-β. WPMY-Cd cells showed a distinct upregulation for these markers when compared to untreated WPMY-1 cells, suggesting that chronic exposure to Cd promotes CAF-like phenotypic transformation in WPMY-Cd. To further ascertain the cancer-promoting properties of WPMY-Cd, an in vitro 3-D spheroid assay was performed by growing the cells on a Matrigel scaffold. The WPMY-Cd cells formed many more tumor-like spheroid structures than WPMY-1 and exhibited sprouting. The sprouting spheroids displayed lamellipodium and filopodium-like structures, demonstrating the initiation of migratory phenotype in WPMY-Cd. Additionally, previous research suggests that CAFs may play a role in PCa progression by promoting tumor growth via the secretion of cytokines and growth factors. We tested this theory by exposing Cd-treated epithelial (BPH-Cd) cells to conditioned media containing secretions from CAFs and WPMY-Cd. WPMY-1 Cd conditioned media in conferring cell migration on epithelial BPH-Cd cells was confirmed by a wound healing assay wherein BPH-Cd cells treated with WPMY-1 Cd conditioned media led to complete wound closure in 24 hours as compared to WPMY-1 and CAF conditioned media. Overall, there is considerable evidence that Cd exposure in fibroblasts may play a crucial role in PCa disease progression and is a promising area for researching PCa treatment strategies against a crucial component of the tumor microenvironment. Citation Format: Sakshi V. Bansod, Gnanasekar Munarithinam. Investigating the carcinogenic effects and the mechanism of cadmium exposure on WPMY-1 prostate myofibroblast cell line [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 1475.

PSA-density, DRE, and PI-RADS 5: potential surrogates for omitting biopsy?

ObjectiveIn contrast to other malignancies, histologic confirmation prior treatment in patients with a high suspicion of clinically significant prostate cancer (csPCA) is common. To analyze the impact of extracapsular extension (ECE), cT-stage defined by digital rectal examination (DRE), and PSA-density (PSA-D) on detection of csPCA in patients with at least one PI-RADS 5 lesion (hereinafter, “PI-RADS 5 patients”).Materials and methodsPI-RADS 5 patients who underwent MRI/Ultrasound fusion biopsy (Bx) between 2016 and 2020 were identified in our institutional database. Uni- and multivariable logistic-regression models were used to identify predictors of csPCA-detection (GGG ≥ 2). Risk models were adjusted for ECE, PSA-D, and cT-stage. Corresponding Receiver Operating Characteristic (ROC) curves and areas under the curve (AUC) were calculated.ResultsAmong 493 consecutive PI-RADS 5 patients, the median age and PSA was 69 years (IQR 63–74) and 8.9 ng/ml (IQR 6.0–13.7), respectively. CsPCA (GGG ≥ 2) was detected in 405/493 (82%); 36/493 patients (7%) had no cancer. When tabulating for PSA-D of > 0.2 ng/ml/cc and > 0.5 ng/ml/cc, csPCA was found in 228/253 (90%, PI-RADS5 + PSA-D > 0.2 ng/ml/cc) and 54/54 (100%, PI-RADS5 + PSA-D > 0.5 ng/ml/cc). Finally, a model incorporating PSA-D and cT-stage achieved an AUC of 0.79 (CI 0.74–0.83).ConclusionIn PI-RADS 5 patients, PSA-D and cT-stage emerged as strong predictors of csPCA at biopsy. Moreover, when adding the threshold of PSA-D > 0,5 ng/ml/cc, all PI-RADS 5 patients were diagnosed with csPCA. Therefore, straight treatment for PCA can be considered, especially if risk-factors for biopsy-related complications such as obligatory dual platelet inhibition are present.

Investigating the structural basis of piperine targeting AKT1 against prostate cancer through in vitro and molecular dynamics simulations

AkT1, significantly impacts many tumours cell functions, like transcription, apoptosis, glucose metabolism, cell proliferation, and cell migration. For tumours to develop and spread, aberrant activation of AKT1 is essential. Therefore, a major focus of molecularly targeted PCa treatment is AKT1. The present study investigates the effect of piperine compared to SDF using in-vitro studies, viz colony formation assay, comet assay and AKT1 gene expression studies using human PCa cell line PC3. A cluster of approximately at least 50 cells constitutes a colony. The clonogenic assay showed that the number and size of colonies significantly decreased when treated with compounds (SDF and piperine) in comparison to the untreated cells which effectively proliferated to form more colonies. Piperine treatment showed significant inhibition of colony formation than SDF. Effective genotoxicity was observed in piperine-treated PC3 cells with an increased Tail length of 120 µm and it was moderately observed in SDF with a Tail length of 30 µm treated on PC3 cells. The control group did not show any considerable genotoxicity with a Tail length of 6 µm. Our data, both in vitro and in silico, suggested that piperine would be a good starting point for developing novel drugs for the treatment of PCa. The downstream functions of Akt1 may be inhibited by these effects, which could impede the proliferation of PCa cells. High stability of the piperine-AKT1 complex was found by the MD simulation. Higher hydrophilic residues like Lys268 and Ser205 at the active pocket may be the cause of the binding stability. Overall, the observed results confirmed the anti-PCa effect of piperine by causing effective DNA damage and proved to be genotoxic in nature against the human PCa. These effects may impede the downstream activities of Akt1 and result in PCa cell growth regression. Communicated by Ramaswamy H. Sarma

The Efficacy of Prostatic Artery Embolization (PAE) as Palliative Therapy in Prostate Cancer

Introduction: Prostate cancer, the primary contributor to cancer-related fatalities in Western countries, predominantly impacts individuals between the ages of 45 and 60. The World Health Organization (WHO) has documented 1,414,259 new cases worldwide. Diagnosis methods include prostate biopsy, PSA testing, and MRI, with risk factors such as age, weight, race, and family history contributing to the varied epidemiology of the disease. Treatment alternatives such as surgery and radiation therapy come with notable side effects, prompting ongoing research into alternatives like prostate artery embolization (PAE) for benign prostatic obstruction. However, the role of PAE in patients with prostate cancer remains uncertain. Aim: The purpose of this systematic review is to determine the efficacy of Prostatic Artery Embolization as one of the palliative management strategies for clinical outcomes in prostate cancer. Method: We searched for English-language full-text literature from Pubmed, Cochrane, Wiley Library, Proquest, SpringerLink, and ScienceDirect databases from January 2013 to Desember 2023. Based on the 1442 journals identified in this study, the number of evaluated articles is 6. Results: In six studies, PAE induces tissue ischemia through femoral artery embolization, offering promise for localized prostate cancer treatment. Administered under local anesthesia, PAE has shorter hospital stays and is well-tolerated compared to TURP. After PAE treatment, significant IPSS reduction occurred, with improved outcomes reported at 1 and 6 months. Histopathology showed necrotic zones, but viable cancer cells persisted. PAE is a valuable adjunctive therapy for reducing organ-at-risk doses in exclusive prostate radiation therapy. Conclusion: PAE is a minimally invasive treatment for LUTS related to BPH and its potential in managing PCa. PAE, utilizing femoral artery occlusion, shows significant short and medium-term reductions in IPSS. While there's notable success in PCa management and reduced radiation doses, further research is essential for a comprehensive understanding of PAE's efficacy in localized PCa treatment.