PCa Therapy Research Articles

Терапевтически индуцированная нейроэндокринная дифференцировка рака предстательной железы.

Introduction. The use of selective highly effective antiandrogen drugs in castration-resistant prostate cancer (CRPC) gradually leads to cellular transformation. Objective. To study current concepts of the prevalence of neuroendocrine differentiation (NED) in patients with CRPC, as well as the treatment of this aggressive variant of PCa. Materials and methods. The results of a search in the scientific databases PubMed, in the scientific electronic library eLibrary.ru were analyzed for the following queries - keywords: treatment-induced neuroendocrine prostate cancer, treatment-emergent neuroendocrine prostate cancer, androgen receptor resistance PCa therapy, neuroendocrine prostate cancer treatment. More than 100 scientific papers published in the last 10 years were found, of which 38 were selected for this review based on the objective of the review. Results. In a number of publications, the linear plasticity of prostate adenocarcinoma (PG) in NE tumor was designated as therapy-induced prostate carcinoma (t-NEPCs). The number of observations of NED PCa is growing, including due to the widespread use of powerful aromatase inhibitors. According to a number of studies, NED PCa is observed in 10-20% of patients with metastatic CRPCa, detected after androgen deprivation therapy and therapy with newgeneration antiandrogens, and the condition is characterized by a highly aggressive course and is accompanied by low survival rates. Conclusion. The high prevalence of NED in patients with CRPC, as well as the lack of effective treatment methods, indicate the need to concentrate efforts on studying this clinically relevant, but insufficiently studied condition. The search for new treatment options for NED PCa based on a patho- genetic complex approach is promising and in demand.

Abstract 61: A novel immunotherapy for metastatic prostate cancer: A monoclonal antibody that can bind both STEAP1 and STEAP2

Abstract Prostate cancer (PCa) is the second most prevalent cancer among males, and the 5-year survival rate for patients with metastatic PCa (mPCa) is ~30%. Although significant progress has been made in improving survival in mPCa patients, many of these patients experience relapse or systemic toxicities. Protein expression of prostate-specific membrane antigen (PSMA), a common PCa antigen often targeted in PCa therapy, is unfortunately lost in the later stages of mPCa. In contrast, six transmembrane epithelial antigen of the prostate 1 and 2 (STEAP1 and STEAP2) are both overexpressed in most PCa compared to normal and vital organs and has emerged as a next-generation target in mPCa. We hypothesize that an antibody that binds to both STEAP1 and STEAP2 via their second extracellular domain (60% homology) could be useful therapeutically. Using an immunogen of this second extracellular domain, we raised several antibody clones that appear to have an affinity towards both STEAP1 and STEAP2 (STEAP1/2). The specificity and affinity of these antibody clones were successfully determined by immunofluorescence, flow cytometry and ELISA. Immunofluorescence results in PCa cell lines and those that overexpress STEAP1 and STEAP2 demonstrate the potential specificity of one clone for human STEAP1 and STEAP2. In addition, ELISA data revealed that the binding affinity of this clone to STEAP1 and STEAP2 is in the low nanomolar and low micromolar range, respectively. This monoclonal STEAP1/2 antibody has been sequenced and will become the basis for future development of immunotherapies thus expanding the therapeutic armamentarium for mPCa. Citation Format: Minzhi Sheng, Gobi Thillainadesan, Amanda Sparkes, Boyang Su, Esther Matus, Jessica Wright, Stanley Liu, Jean Gariepy, Hon S. Leong. A novel immunotherapy for metastatic prostate cancer: A monoclonal antibody that can bind both STEAP1 and STEAP2 [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 61.

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.

Bioinformatics-Assisted Extraction of All PCa miRNAs and their Target Genes.

To retrieve, and classify PCa miRNAs and identify the functional relationship between miRNAs and their targets through literature collection with computational analysis. MicroRNAs play a role in gene regulation, which can either repress or activate the gene. Hence, the functions of miRNAs are dependent on the target gene. This study will be the first of its kind to combine computational analysis with corpus PCa data. Effectively, our study reported the huge number of miRNAs associated with PCa along with functional information. The identification and classification of previously known full PCa miRNAs and their targets were made possible by mining the literature data. Systems Biology and curated data mining assisted in identifying optimum miRNAs and their target genes for PCa therapy. PubMed database was used to collect the PCa literature up to December 2021. Pubmed. mineR package was used to extract the microRNAs associated articles and manual curation was performed to classify the microRNAs based on the function in PCa. PPI was constructed using the STRING database. Pathway analysis was performed using PANTHER and ToppGene Suite Software. Functional analysis was performed using ShinyGO software. Cluster analysis was performed using MCODE 2.0, and Hub gene analysis was performed using cytoHubba. The genemiRNA network was reconstructed using Cytoscape. Unique PCa miRNAs were retrieved and classified from mined PCa literature. Six hundred and five unique miRNAs from 250 articles were considered as oncomiRs to trigger PCa. One hundred and twenty unique miRNAs from 118 articles were considered Tumor Suppressor miRNAs to suppress the PCa. Twenty-four unique miRNAs from 22 articles were utilized as treatment miRNAs to treat PCa. miRNAs target genes and their significant pathways, functions and hub genes were identified. miR-27a, miR-34b, miR-495, miR-23b, miR-100, miR-218, Let-7a family, miR-27a- 5p, miR-34c, miR-34a, miR-143/-145, miR-125b, miR-124 and miR-205 with their target genes AKT1, SRC, CTNNB1, HRAS, MYC and TP53 are significant PCa targets.

Abstract 1455: The glucocorticoid receptor-LEDGFp75 interaction in prostate cancer therapy cross-resistance

Abstract Prostate cancer (PCa) is the second leading cause of cancer deaths in the U.S., disproportionally affecting African American (AA) men. PCa patients with recurrent disease develop therapy resistance and fail to respond to both anti-androgen receptor signaling (ARSI) therapy and taxane-based chemotherapy. Glucocorticoid receptor, a transcription factor, has been implicated in resistance to ARSI (via the GR bypass), and docetaxel (DTX) therapies. However, the mechanisms underlying this GR-mediated therapy cross-resistance are poorly understood. Previously, we demonstrated that glucocorticoids, which are co-administered with current PCa therapies and activate GR signaling, upregulate the chemoresistance-associated transcription coactivator LEDGFp75 in PCa cells. We also identified consensus GR binding sites in the promoter region of the gene encoding LEDGFp75, suggesting it is a GR target gene. We hypothesized that GR transcriptionally upregulates LEDGFp75 and then interacts with this protein in the nucleus to promote DTX resistance in PCa cells. Genetic silencing of GR in a panel of DTX-sensitive and -resistant PCa cell lines decreased the expression of LEDGFp75 at both the protein and transcript levels, confirming its status as a candidate GR target gene. However, genetic silencing of LEDGFp75 had no effects on GR protein expression. Pharmacological inhibition of GR also decreased LEDGFp75 in DTX-sensitive cells. The effects of Exicorilant and Relacorilant (Corcept Therapeutics) were evaluated on LEDGFp75 protein expression levels. Immunoprecipitation and confocal microscopy studies revealed that GR and LEDGFp75 interact in the nucleus of PCa cells. Interestingly, upregulation of GR in enzalutamide resistant LNCaP cells correlated with LEDGFp75 upregulation, and GR silencing in these cells decreased this upregulation. These results suggested a possible role for GR and LEDGFp75 in PCa therapy cross-resistance. Further studies are underway to determine if co-targeting these two proteins genetically and pharmacologically attenuates both enzalutamide resistance and DTX resistance and other aggressive properties of PCa cells. In addition, RNAseq studies have been initiated to determine the degree of transcriptional overlap between GR and LEDGFp75 in chemoresistant PCa cells. Our goal is to link mechanistically the GR-LEDGFp75 transcriptional network to ARSI/taxane cross-resistance in PCa and target this network to attenuate therapy resistance. Citation Format: Evelyn S. Sanchez-Hernandez, Pedro T. Ochoa, Greisha L. Ortiz-Hernandez, Shannalee Martinez, Carlos Casiano. The glucocorticoid receptor-LEDGFp75 interaction in prostate cancer therapy cross-resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1455.

Cuproptosis illustrates tumor micro-environment features and predicts prostate cancer therapeutic sensitivity and prognosis

BackgroundProstate cancer (PCA) is a common malignant genitourinary tumor that significantly impacts patient survival. Cuproptosis, a copper-dependent programmed cell death mechanism, plays a vital role in tumor development, therapy resistance, and immune microenvironment regulation in PCA. However, research on cuproptosis in prostate cancer is still in its early stages. MethodsUsing the publicly available datasets TCGA and GEO, we first acquired the transcriptome and clinical information of PCA patients. The expression of cuprotosis-related genes (CRG) was identified and a prediction model was established based on LASSO-COX method. The predictive performance of this model was evaluated based on Kaplan-Meier method. Using GEO datasets, we further confirmed the critical genes level in the model. Tumor responses to immune checkpoint (ICP) inhibitors were predicted based on Tumor Immune Dysfunction and Exclusion (TIDE) score. The Genomics of Drug Sensitivity in Cancer (GDSC) was utilized to forecast drug sensitivity in cancer cells, whereas the GSVA was employed to analyze enriched pathways related to the cuproptosis signature. Subsequently, the function of PDHA1 gene in PCA was verified. ResultsA predictive risk model on basis of five cuproptosis-related genes (ATP7B, DBT, LIPT1, GCSH, PDHA1) were established. The progression free survival of low-risk group was obviously longer than the high-risk group, and exhibit better response to ICB therapy.Furthermore,PDHA1 is very important in the pathological process of PCA according to regressions analysis result, and the validation of external data sets were conducted. High PDHA1 expression patients with PCA not only had a shorter PFS and were less likely to benefit from ICB treatment, but they were also less responsive to multiple targeted therapeutic drugs. In preliminary research, PDHA1 knockdown significantly decreased the proliferation and invasion of PCA cells. ConclusionThis study established a novel cuproptosis-related gene-based prostate cancer prediction model that accurately predicts the prognosis of PCA patients. The model benefits individualized therapy and can assist clinicians in making clinical decisions for PCA patients. Furthermore, our data show that PDHA1 promotes PCA cell proliferation and invasion while modulating the susceptibility to immunotherapy and other targeted therapies. PDHA1 can be regarded as an important target for PCA therapy.

A novel L-phenylalanine dipeptide inhibits prostate cancer cell proliferation by targeting TNFSF9

In the present study, a series of novel L-phenylalanine dipeptides were designed and synthesized by a multi-step sequence of reactions, including carbodiimide-mediated condensation, hydrolysis, mixed anhydride condensation, and nucleophilic substitution. Among them, compound 7c exhibited potent antitumor activity against prostate cancer cell PC3 in vitro and in vivo via inducing apoptosis. We investigated the significantly differentially expressed proteins in the cells caused by the compound 7c to unravel the molecular mechanisms underlying the regulation of PCa cell growth, which indicated that 7c mainly regulated the protein expression of apoptosis-related transcription factors, including c-Jun, IL6, LAMB3, OSMR, STC1, OLR1, SDC4 and PLAU; and 7c also regulated the protein expression of inflammatory cytokines including IL6, CXCL8, TNFSF9, TNFRSF12A and OSMR, and the phosphorylation levels of RelA. The action target confirmed that TNFSF9 protein is the critical binding target of 7c. These findings suggested that 7c could regulate the apoptosis and inflammatory response related signaling pathways for the inhibition of the proliferation of PC3 cells, implying that 7c could be considered a promising therapeutic candidate for PCa therapy.

NRF2: A crucial regulator for mitochondrial metabolic shift and prostate cancer progression.

Metabolic alterations are a common survival mechanism for prostate cancer progression and therapy resistance. Oxidative stress in the cellular and tumor microenvironment dictates metabolic switching in the cancer cells to adopt, prosper and escape therapeutic stress. Therefore, regulation of oxidative stress in tumor cells and in the tumor-microenvironment may enhance the action of conventional anticancer therapies. NRF2 is the master regulator for oxidative stress management. However, the overall oxidative stress varies with PCa clinical stage, metabolic state and therapy used for the cancer. In agreement, the blanket use of NRF2 inducers or inhibitors along with anticancer therapies cause adverse effects in some preclinical cancer models. In this review, we have summarized the levels of oxidative stress, metabolic preferences and NRF2 activity in the different stages of prostate cancer. We also propose condition specific ways to use NRF2 inducers or inhibitors along with conventional prostate cancer therapies. The significance of this review is not only to provide a detailed understanding of the mechanism of action of NRF2 to regulate oxidative stress-mediated metabolic switching by prostate cancer cells to escape the radiation, chemo, or hormonal therapies, and to grow aggressively, but also to provide a potential therapeutic method to control aggressive prostate cancer growth by stage specific proper use of NRF2 regulators.

Abstract 6319: Defense mechanism against oxidative damage in metastatic prostate cancer: Adipocyte-mediated modulation of mTOR and ferroptosis pathways

Abstract Prostate cancer (PCa) is the most common cancer amongst males and becomes incurable once it advances to the secondary site. The most common site of metastasis from PCa is the adipocyte-rich bone marrow. Adipocytes are metabolically active cells capable of secreting a variety of adipokines and free fatty acids, which can be utilized by tumor cells to enhance proliferation and cause resistance to chemotherapies. Our lab has shown that adipocytes promote PCa progression and therapy evasion through modulation of tumor metabolism and activation of pro-survival signaling; however, the molecular mechanisms behind tumor-promoting effects of fat cells are not understood. It is well known that high levels of iron within the tumor microenvironment help the growth of PCa cells. However, since iron overload can cause an increase in reactive oxygen species (ROS), which are harmful to cell structure, tumor cells have developed defense mechanisms to protect them from this oxidative damage. Intriguingly, our data show that the expression of ferritin, an iron storing protein, is reduced in PC3 and ARCaP(M) cells in co-culture with adipocytes. Since low ferritin levels have been associated with induction of ferroptosis, an iron and oxidative stress-regulated cell death process, we examined protein levels of ferroptosis markers GPX4 and NCOA4 in PCa cells. Surprisingly, our data show that interaction with adipocytes increases GPX4 and reduces NCOA4 expression in PCa cells suggesting an adipocyte-mediated defense mechanism against ferroptosis. The aim of the present study was to establish that adipocytes promote a defense mechanism against ferroptosis in PCa cells by the upregulation of GPX4 activity via the mTOR pathway. GPX4 is known to be an essential antioxidant enzyme that utilizes glutathione (GSH) to reduce lipid-peroxidation-induced ROS. We demonstrate that PCa cells exposed to adipocytes have reduced lipid-peroxidation induced ROS, which can be reversed with ferroptosis inducers. We also show that exposure of PC3 and ARCaP(M) cells to adipocytes leads to depletion of GSH, which may be indicative of higher GPX4 activity. It has been suggested that an increase in GPX4 can result from an interplay between ferroptosis and mTOR pathways, specifically mTORC1, which may mediate cysteine-induced GPX4 protein synthesis. Surprisingly, treatment of PCa cells co-cultured with adipocytes with mTORC1 inhibitor Everolimus (EVO) increases the protein and gene levels of GPX4. This coincides with reduced mRNA and protein expression of SLC7A11, transporter involved in the cysteine/glutamate antiporter system, which typically fuels GPX4 activity by bringing in the GSH precursor cysteine. Understanding the mechanisms of fat cell contribution to dysregulation of the mTOR pathway and escape from ferroptosis may have therapeutic implications for metastatic PCa. Citation Format: Alexis Wilson, Shane Mecca, Mackenzie Herroon, Laimar Garmo, Izabela Podgorski. Defense mechanism against oxidative damage in metastatic prostate cancer: Adipocyte-mediated modulation of mTOR and ferroptosis pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6319.

PELO facilitates PLK1-induced the ubiquitination and degradation of Smad4 and promotes the progression of prostate cancer.

PLK1 and Smad4 are two important factors in prostate cancer initiation and progression. They have been reported to play the opposite role in Pten-deleted mice, one is an oncogene, the other is a tumor suppressor. Moreover, they could reversely regulate the PI3K/AKT/mTOR pathway and the activation of MYC. However, the connections between PLK1 and Smad4 have never been studied. Here, we showed that PLK1 could interact with Smad4 and promote the ubiquitination and degradation of Smad4 in PCa cells. PLK1 and PELO could bind to different domains of Smad4 and formed a protein complex. PELO facilitated the degradation of Smad4 through cooperating with PLK1, thereby resulting in proliferation and metastasis of prostate cancer cell. Changes in protein levels of Smad4 led to the alteration of biological function that caused by PLK1 in prostate cancer cells. Further studies showed that PELO upregulation was positively associated with high grade PCa and knockdown of PELO expression significantly decreased PCa cell proliferation and metastasis in vitro and vivo. PELO knockdown in PCa cells could enhance the tumor suppressive role of PLK1 inhibitor. In addition, blocking the interaction between PELO and Smad4 by using specific peptide could effectively inhibit PCa cell metastasis ability in vitro and vivo. Overall, these findings identified a novel regulatory relationship among PLK1, Smad4 and PELO, and provided a potential therapeutic strategy for advanced PCa therapy by co-targeting PLK1 and PELO.

Factors Associated With Inflatable Penile Prosthesis Underutilization After Prostate Cancer Treatment

ABSTRACT Introduction Penile Prosthesis (IPP) is an effective treatment for men with ED that significantly improves quality of life but is likely being underutilized in men who were treated for prostate cancer (Pca). Objective To better characterize the utilization of IPP treatment after Pca therapy, we explored the relationship between timing of ED diagnosis (before vs after treatment), treatment modality (radiation vs. prostatectomy), and various sociodemographic factors in a national cohort. Methods We performed a retrospective review of SEER-Medicare patients who were diagnosed with local/regional Pca between 2006 and 2011.Using ICD9/CPT/HCPCS codes, we created a subset of patients who were diagnosed with ED 12 months prior to their Pca treatment, until 5 years after. Chi-square/Wilcoxon tests were used to detect significant differences between the use of IPP among those with ED prior to Pca treatment compared to after. In addition, various sociodemographic factors were examined. Results Of the 31,854 patients in our cohort, 14,482 (45.5%) were diagnosed with ED within 12 months prior to Pca diagnosis or 5 years after diagnosis. Among those diagnosed with ED prior to treatment (4366, 30.1%), 119 (2.7%) received IPP while among the 10,116 patients (69.9%) with ED diagnosis after treatment, 232 (2.3%) received IPP. Among patients with ED, factors decreasing the likelihood of receiving an IPP were diagnosis of ED prior to Pca treatment (OR=1.33, 95% CI: 1.06-1.66), relationship status of single (OR=1.88, 95% CI: 1.28-2.77) or divorced/separated (OR=2.13, 95% CI: 1.46-3.10), and identifying as Non-Hispanic Black (OR=1.72, 95% CI:1.24-2.37) or Hispanic (OR=1.81, 95% CI: 1.22-2.67) as compared to Non-Hispanic White men. Factors decreasing the likelihood of receiving an IPP were being treated with radiation therapy as opposed to prostatectomy (OR=0.38, 95% CI: 0.29-0.49), and increased age (OR=0.75 95% CI: 0.63-0.88). Conclusions Although more men have their ED treated with an IPP if they received their diagnosis prior to Pca treatment (2.7% vs. 2.3%), IPPs appear to be underutilized in all patients with ED after Pca therapy. This data suggests that factors (i.e. prior ED diagnosis, being single, Black or Hispanic) outside of the typically accepted medical indications may influence IPP selection as a treatment option for ED. Conversely, counseling pertaining to IPP surgery after Pca treatment may be lacking in men with newly diagnosed ED, married men, white men, older men, and men who received radiation therapy. More thorough evaluation of these demographic factors is warranted. Disclosure No

Long Noncoding RNA SNHG12 Promotes Prostate Tumor Occurrence and Progression via AKT Regulation.

The small nucleolar RNA host gene 12 (SNHG12) has been reported to play an important role in the tumorigenesis and progression of PCa, but the functional underlying mechanism has not been studied clearly. We detected the expression level of SNHG12 in PCa tissues and matched adjacent normal tissues that were collected from 85 patients. Then, colony formation assays, MTT experiments, and flow cytometry were used to examine the effect of SNHG12 on proliferation, cell cycle distribution, and apoptosis of DU145 cells. Further, Transwell invasion assay was utilized to assess whether SNHG12 participates in PCa cell invasion and affects the secretion of VEGF secretion in DU145 cells. Finally, we investigated the effect of SNHG12 on tumor growth in vivo. We found that SNHG12 promoted cell proliferation and suppressed apoptosis in PCa cells, which suggests that SNHG12 is probably a novel PCa biomarker and therapy target of PCa.

LINC01006 facilitates cell proliferation, migration and invasion in prostate cancer through targeting miR-34a-5p to up-regulate DAAM1

BackgroundProstate cancer (PCa) is a kind of malignancy occurring in the prostate gland. Substantial researches have proved the major role of long noncoding RNAs (lncRNAs) in PCa. However, the role of long intergenic non-protein coding RNA 1006 (LINC01006) in PCa has not been investigated yet.MethodsRT-qPCR was used to examine the expression levels of LINC01006 and its downstream targets. The function of LINC01006 in PCa was tested by in vitro and in vivo assays. With application of RNA pull down, RNA immunoprecipitation (RIP) and luciferase reporter assays, the interaction among LINC01006, miR-34a-5p and disheveled associated activator of morphogenesis 1 (DAAM1) were verified.ResultsLINC01006 expression presented high in PCa cell lines. LINC01006 silencing suppressed cell proliferative, migratory, invasive capacities while accelerated apoptotic rate. Besides, LINC01006 knockdown also suppressed tumor growth and metastasis in vivo. Furthermore, miR-34a-5p, a tumor suppressor in PCa, was sponged by LINC01006. Moreover, DAAM1 was targeted by miR-34a-5p and promoted PCa progression. More intriguingly, rescue assays suggested that the inhibitory effect of LINC01006 knockdown on PCa development was offset by DAAM1 overexpression.ConclusionsLINC01006 promoted PCa progression by sponging miR-34a-5p to up-regulate DAAM1, providing a novel target for PCa therapy.

Poly(ADP-Ribose) Polymerase Inhibitors in Prostate Cancer: Molecular Mechanisms, and Preclinical and Clinical Data.

Genomic instability is one of the hallmarks of cancer. The incidence of genetic alterations in homologous recombination repair genes increases during cancer progression, and 20% of prostate cancers (PCas) have defects in DNA repair genes. Several somatic and germline gene alterations drive prostate cancer tumorigenesis, and the most important of these are BRCA2, BRCA1, ATM and CHEK2. There is a group of BRCAness tumours that share phenotypic and genotypic properties with classical BRCA-mutated tumours. Poly(ADP-ribose) polymerase inhibitors (PARPis) show synthetic lethality in cancer cells with impaired homologous recombination genes, and patients with these alterations are candidates for PARPi therapy. Androgen deprivation therapy is the mainstay of PCa therapy. PARPis decrease androgen signalling by interaction with molecular mechanisms of the androgen nuclear complex. The PROFOUND phase III trial, comparing olaparib with enzalutamide/abiraterone therapy, revealed increased radiological progression-free survival (rPFS) and overall survival (OS) among patients with metastatic castration-resistant prostate cancer (mCRPC) with BRCA1, BRCA2 or ATM mutations. The clinical efficacy of PARPis has been confirmed in ovarian, breast, pancreatic and recently also in a subset of PCa. There is growing evidence that molecular tumour boards are the future of the oncological therapeutic approach in prostate cancer. In this review, we summarise the data concerning the molecular mechanisms and preclinical and clinical data of PARPis in PCa.

S1348 Triple Therapy for Primary Treatment of Helicobacter pylori: A 19-Year U.S. Single Center Experience

INTRODUCTION: Helicobacter pylori (H.pylori) is an important worldwide cause of peptic ulcer disease, gastric cancer and upper gastrointestinal symptoms. Triple therapy with a proton pump inhibitor, clarithromycin, and amoxicillin (PCA) or metronidazole (PCM) for 14 days remains the mainstay of first-line therapy for H. pylori infection in the US, however, there is evidence that antibiotic resistance, particularly to macrolides, is increasing in the United States (US). Aim: (i) Determine the effectiveness of PCA & PCM for eradicating H.pylori infection over the past 19 years (ii) Determine the impact of compliance on eradication rates with PCA & PCM. METHODS: A retrospective analysis was performed on all patients (pts) referred for a 13C urea breath test (UBT) following first line PCA or PCM therapy for H. pylori at a single US medical center between January 2001 – October 2019. Patients included in this analysis had H. pylori infection documented by gastric biopsy, UBT or fecal antigen test. All patients were treated with PCA or PCM for 10-14 days. Time frames for comparison included a cure rate over the entire 19-year study period and sub-divided into four 5-year blocks (2001-2005, 2006-2010, 2011-2015, and 2016-2019). Cure rates & 95% confidence intervals were calculated for PCA & PCM combined and each regimen separately. Logistic regression was conducted to determine if therapy compliance influenced H.pylori eradication. RESULTS: Data was analyzed on 1058 pts (mean age 51.1 (SD = 15.4; Range:18-90), 61.8% female, and 49.5% Caucasian). H.pylori eradications rates using PCA or PCM was 78.1%. PCA (79.1%) and PCM yielded similar eradication rates (79.1% vs. 77.8%, NS). Eradication rates for PCA & PCM divided into 5-year time blocks were similar [Table 1]. Therapy compliance did not significantly influence eradication rates. CONCLUSION: Real world eradication rates of PCA & PCM at a large midwestern US medical center have remained stable over almost 2 decades. The eradication rates of < 80% raise questions about whether these regimens deserve to be the preferred first-line therapies for H. pylori in the US.Table 1.: Cumulative Eradication Rates (2001-2019)Table 2.: Five Year Interval Eradication Rates

P18 Provocation of paediatric hearts – a safe and smart solution

AimsProvocation challenges are used to diagnose certain inherited life-threatening cardiac conditions; treatment can prevent malignant arrhythmias and sudden death. Provocation medications are administered to unmask pathognomic conduction characteristics on real-time electrocardiography. Pre-prepared rescue medications are administered should a ventricular arrhythmia be unintentionally provoked. These high-risk medications, in line with safety agency recommendations, should be delivered using smart-pump technology.1 They are also often unlicensed and expensive.2 We investigated the utilisation of smart-pumps and development of a guideline to optimise medicines management and safety of these procedures in an Irish tertiary paediatric hospital.MethodsPublished literature and current practices, including those in other paediatric and adult hospitals in Ireland and the UK, were reviewed to ascertain appropriate dosing and administration in the paediatric population.3 4 Multi-disciplinary input from nursing, cardiology, pharmacy and biomedical engineering was sought in guideline development.ResultsEvidence for such challenges in paediatrics is sparse. Suitable dosing was agreed and an indication-specific smart-pump drug library created. The ‘PCA Therapy’ module was employed to deliver repeated weight-based doses of the provocation medication (Ajmaline) in a controlled and timely manner; the rescue medication (Isoprenaline) was programmed as a continuous infusion. An auxillary calculator was developed in Microsoft Excel® to direct staff on preparation of both infusion solutions and bolus doses of medications to be manually administered (Magnesium and Isoprenaline). In 2017, relevant staff were trained, and the ‘Ajmaline Challenge’ guideline was approved and implemented in the Cardiac Catherisation Laboratory (CCL) and Cardiac Day Unit. Estimated cost savings of €19,400 were realised between January 2017 - October 2018 due to reduced wastage of unused medications. Further savings are likely due to decreased utilisation of the CCL.ConclusionMulti-disciplinary collaboration and health technology can improve the safety and cost-effectiveness of high-risk cardiac diagnostic procedures in the paediatric setting. Similar processes for other provocation challenges are under development.ReferencesInstitute for Safe Medication Practices, ISMP. 2018–2019 Targeted Medication Safety Best Practices for Hospitals 2018 [Available from: https://www.ismp.org/sites/default/files/attachments/2017-12/TMSBP-for-Hospitalsv2.pdf [Accessed: June 2019]European Commission. State of Paediatric Medicines in the EU - 10 years of the EU Paediatric Regulation 2017 [Available from: https://ec.europa.eu/health/sites/health/files/files/paediatrics/docs/2017_childrensmedicines_report_en.pdf [Accessed: June 2019]McMillan MR, Day TG, Bartsota M, et al. Feasibility and outcomes of ajmaline provocation testing for Brugada syndrome in children in a specialist paediatric inherited cardiovascular diseases centre. Open Heart 2014;1:e000023.Rolf S, Bruns HJ, Wichter T, et al. The ajmaline challenge in Brugada syndrome: diagnostic impact, safety, and recommended protocol. Eur Heart J. 2003;24:1104–12.

Abstract D116: Glucocorticoid receptor interacts with beta-catenin to promote stemness and therapy resistance in prostate cancer cells

Abstract Prostate cancer (PCa) is the most commonly diagnosed male cancer, with men of African ancestry showing a disproportionately high incidence and mortality. There is increasing evidence that glucocorticoid signaling through glucocorticoid receptor (GR) is amplified in African American men due to cumulative life stress, and that GR signaling is a key driver of resistance to androgen-targeted therapy, radiotherapy, and taxane chemotherapy in advanced PCa. Recent studies indicate that GR also promotes in PCa cells the formation of tumorspheres, a property of cancer stem cells (CSC); however, the mechanisms remain unclear. CSCs are intrinsically resistant to therapies due to their low-frequency, expression of transporters and efflux pumps, quiescent cell cycle and metabolic profile. Our previous studies demonstrated that docetaxel (DTX)-resistant PCa cells exhibit increased capacity for CSC-like properties, suggesting that these properties contribute to chemoresistance. Like GR, beta-catenin is overexpressed in metastatic and therapy-resistant tumors, and is considered a key regulator of cancer stemness and androgen-targeted therapy resistance. Thus, we hypothesized that GR may interact with beta-catenin in PCa cells to support stemness and chemoresistance. Using whole-cell and nuclear co-immunoprecipitation, we demonstrated the interaction between GR and beta-catenin in several DTX-sensitive and -resistant PCa cell line pairs. Pharmacological inhibition of GR using the selective inhibitor CORT-108297 with concomitant inhibition of beta-catenin using the small molecule inhibitor MSAB significantly enhanced DTX cytotoxicity in resistant PCa cells grown in both adherent and spheroid cultures. The BET bromodomain inhibitor JQ1, an antagonist of enhancer-mediated GR upregulation, also significantly reduced tumorsphere formation and stemness in DTX-resistant PCa cells. In order to gain insights into transcriptomic profiles activated by GR signaling that may contribute to stemness and therapy resistance, we performed RNA sequencing in a racially diverse panel of PCa cell lines (MDA-PCa-2b, VCaP, 22RV1, and PC3) treated with and without dexamethasone, a potent glucocorticoid. We observed that the African American cell line MDA-PCa-2b yielded the largest number of differentially regulated genes, perhaps due to the ability of dexamethasone to signal through both AR and GR in this particular cell line. RNAseq data is currently being mined and validated in cellular models treated with glucocorticoids or androgens, in the presence or absence of anti-GR or anti-androgen inhibitors, in order to identify GR-regulated genes. Our results offer novel insights into mechanisms by which GR signaling may influence tumorsphere formation and stemness, and suggest that combinatorial targeting of GR and beta-catenin could be a promising therapeutic strategy to overcome PCa therapy resistance and consequently reduce PCa mortality and its racial disparities. Citation Format: Shannalee R Martinez, Evelyn S Sanchez-Hernandez, Xin Chen, Alfonso M Duran, Charles H Wang, Carlos A Casiano. Glucocorticoid receptor interacts with beta-catenin to promote stemness and therapy resistance in prostate cancer cells [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D116.

Radical prostatectomy versus brachytherapy for clinically localized prostate cancer on oncological and functional outcomes: a meta-analysis.

BackgroundProstate cancer (PCa) is a form of malignancy that harms the health status of elderly men worldwide. It is unclear which of radical prostatectomy (RP) or brachytherapy (BT) is the more effective treatment for PCa. This study presents the first highly comprehensive and up-to-date comparative analysis of the overall outcomes of RP versus BT.MethodsWe conducted a systematic literature search for studies published on PubMed, EMBASE, and the Cochrane Library on the outcomes of RP versus BT in clinically localized PCa. The cumulative analysis was performed using Review Manager Version 5.3 software, and the Chi-square test was employed to test the statistical heterogeneity. The summary odds ratio (OR) and standard mean difference (SMD) was estimated using random effects models at 95% confidence intervals (CIs).ResultsIn total, 2 randomized, 2 prospective, and 21 retrospective comparative studies were included. No significant differences in biochemical recurrence rate (BCR) (OR: 1.24; 95% CI: 0.91, 1.68) and prostate cancer-specific mortality (PCSM) (OR: 1.62; 95% CI: 0.86, 3.04) between RP and BT were noted. With erectile dysfunction and urinary incontinence, BT was more protective than RP in both short-term post-operative reports (OR: 2.06; 95% CI: 1.15, 3.70 and OR: 4.62; 95% CI: 2.33, 9.16) and long-term patient outcome reports (SMD: −5.62; 95% CI: −13.81, 2.57 and SMD: −11.52; 95% CI: −18.32, −4.72).ConclusionsBT and RP for PCa therapy pose comparable risks of PCSM and BCR, while BT is associated with a lower incidence of erectile dysfunction and urinary incontinence. This study tentatively confirms that BT is an alternative to RP for patients seeking a curative treatment with minimal risks of urinary incontinence and sexual dysfunction.

Polymer Nanoplatforms at Work in Prostate Cancer Therapy

AbstractProstate cancer (PCa) is the most common male urogenital malignancy worldwide. Surgery, endocrine therapy, radiotherapy, and chemotherapy are the main clinical management options for PCa. However, these three therapies each have limitations. For example, surgery is not suitable for the advanced PCa patients with extensive metastases, and radiotherapy causes serious side effects. Primary endocrine therapy promotes the progression of hormone‐sensitive PCa into the castration‐resistant prostate cancer. Therefore, considering these drawbacks, chemotherapy has become an effective and extensive treatment for PCa. Among the modern therapeutic strategies against advanced PCa, polymer‐nanocarrier‐incorporated formulations have gradually emerged due to their well‐controlled release profiles and improved tumor targeting abilities. The drug delivery systems based on polymer nanoplatforms passively target tumors via the enhanced permeability and retention effect. Simultaneously, stimuli‐responsive polymer nanoplatforms unload cargoes in response to certain stimuli in the tumor area. Furthermore, the active targeting ligand‐conjugated polymer nanoformulations against PCa‐specific markers have also achieved great success in PCa therapies. Herein, the advanced polymer nanoplatforms for PCa therapy are reviewed, while the future development of polymer nanoplatforms for PCa therapy is also predicted.

Abstract 5043: Glucocorticoids trigger GR-mediated expression of the chemoresistance-associated oncoproteins LEDGF/p75 and Clusterin: Implications for prostate cancer health disparities

Abstract Prostate cancer (PCa) is more aggressive in African American (AA) men compared to European American (EA) men, resulting in increased incidence and mortality disparities. There is a critical need to identify biological determinants contributing to these disparities. Glucocorticoids—a type of stress hormone—have recently been implicated as biological factors driving PCa progression and response to therapy. The underlying mechanism involves endogenous glucocorticoid binding to its receptor (GR), prompting GR to transcriptionally activate genes that are typically androgen-regulated and that promote tumor aggressiveness and therapy resistance. However, a clinical dilemma exists as glucocorticoids, necessary in the palliative care of PCa patients, are now emerging as accelerators of disease progression. In addition, AA men have chronically elevated levels of glucocorticoids linked to stressful life events, and are also hypersensitive to glucocorticoid exposure. We examined the effects of glucocorticoids on the activation of the stress oncoproteins LEDGF/p75 (Lens Epithelium Derived Growth Factor of 75kd) and CLU (Clusterin), linked by our group and others to prostate tumor aggressivenes and taxane resistance. Our goal is to establish the interplay between glucocorticoids and the expression of these proteins in the context of PCa health disparities. We hypothesized that LEDGF/p75 and CLU may be induced by glucocorticoids through GR in PCa cells. Treatment of a racially diverse panel PCa cell lines (MDA-PCa-2b [AA], 22Rv1 [AA/EA], PC3 [EA], and DU145 [EA]) with 10nM cortisol or dexamethasone for up to 48h significantly upregulated both transcript and protein levels of LEDGF/p75 and CLU. This upregulation was more robust in the AA cell lines. Depletion of GR with siRNAs abrogated dexamethasone-induced upregulation of LEDGF/p75 and CLU. Pharmacological inhibition of GR with mifepristone, in the presence of dexamethasone, also abrogated the induction of these proteins in a cell type-dependent manner. We also observed that dexamethasone exposure increased cell migration, a characteristic of tumor aggressiveness. Furthermore, using an ELISA platform we detected increased serum levels of LEDGF/p75 in AA PCa patients, as well as increased levels of CLU in non-PCa AA men, compared to EA patients and controls. These findings show that glucocorticoids induce the expression of oncoproteins associated with PCa aggressiveness and therapy resistance, and this upregulation may occur more robustly in AA men, priming them to develop highly aggressive PCa tumors. Citation Format: Leanne Woods-Burnham, Christina K. Cajigas-Du Ross, Anamika Basu, Evelyn S. Sanchez, Arthur Love, Carlos A. Casiano. Glucocorticoids trigger GR-mediated expression of the chemoresistance-associated oncoproteins LEDGF/p75 and Clusterin: Implications for prostate cancer health disparities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5043.