Androgen Receptor Target Research Articles

Targeting androgen receptor (AR) with a synthetic peptide increases apoptosis in triple negative breast cancer and AR-expressing prostate cancer cell lines.

The androgen receptor (AR) has been studied as an approach to cancer therapy. We used human breast cancer-derived cells with high, low, and very low expression levels of AR, in addition to prostate cancer-derived LNCaP and DU-145 cells as a positive and negative controls to examine apoptosis caused by a synthetic peptide that targets ARs. The peptide was produced to inhibit AR transactivation in breast cancer cell lines. We then measured cell viability, caspase-3 activity, and the ratio of Bax/Bcl-2. The findings indicated that the peptide (100-500 nM) in the presence of dihydrotestosterone (DHT) reduced cell growth in cells with high and low expression level of AR (p < .001), but not in cells with very low levels of AR. Treatment with 100-500 nM of peptide activated caspase-3 and increased the ratio of Bax/Bcl-2 in cells with high and low expression levels of AR. Also, increasing concentrations of the peptide (100-500 nM) reduced BrdU incorporation in the presence of DHT and promoted apoptosis in cells with high and low expression levels of AR (p < .001). The findings indicate the peptide significantly increased apoptosis in cancer cells.

Introduction of Androgen Receptor Targeting shRNA Inhibits Tumor Growth in Patient-Derived Prostate Cancer Xenografts.

Patient-derived xenograft (PDX) models have been established as important preclinical cancer models, overcoming some of the limitations associated with the use of cancer cell lines. The utility of prostate cancer PDX models has been limited by an inability to genetically manipulate them in vivo and difficulties sustaining PDX-derived cancer cells in culture. Viable, short-term propagation of PDX models would allow in vitro transfection with traceable reporters or manipulation of gene expression relevant to different studies within the prostate cancer field. Here, we report an organoid culture system that supports the growth of prostate cancer PDX cells in vitro and permits genetic manipulation, substantially increasing the scope to use PDXs to study the pathobiology of prostate cancer and define potential therapeutic targets. We have established a short-term PDX-derived in vitro cell culture system which enables genetic manipulation of prostate cancer PDXs LuCaP35 and BM18. Genetically manipulated cells could be re-established as viable xenografts when re-implanted subcutaneously in immunocompromised mice and were able to be serially passaged. Tumor growth of the androgen-dependent LuCaP35 PDX was significantly inhibited following depletion of the androgen receptor (AR) in vivo. Taken together, this system provides a method to generate novel preclinical models to assess the impact of controlled genetic perturbations and allows for targeting specific genes of interest in the complex biological setting of solid tumors.

Discovery of dolutegravir-1,2,3-triazole derivatives against prostate cancer via inducing DNA damage

Prostate cancer (PCa) is the second most frequently diagnosed cancer among men, causing a huge number of deaths each year. Traditional chemotherapy for PCa mostly focused on targeting androgen receptors. However, some of the patients would develop resistance to hormonal therapy. In these cases, it is suggested for these patients to administer treatments in combination with other chemotherapeutics. Current chemotherapeutics for metastatic castration-resistant PCa could hardly reach satisfying effects, therefore it is crucial to explore novel agents with low cytotoxicity. Herein, a common drug against the human immunodeficiency virus (HIV), the dolutegravir (DTG) was modified to become a series of dolutegravir-1,2,3-triazole derivatives. Among these compounds, the 4d and 4q derivatives were verified with high anti-tumor efficiency, suppressing the proliferation of the prostate cancer cells PC3 and DU145. These compounds function by binding to the poly (adenosine diphosphate-ribose) polymerase (PARP), inactivating the PARP and inducing DNA damage in cancer cells. It is noteworthy that the 4d and 4q derivatives showed almost no impact on normal cells and mice. Thereby, the results reveal that these dolutegravir-1,2,3-triazole compounds are potential chemotherapeutics for PCa treatment.

Making the Case for Autophagy Inhibition as a Therapeutic Strategy in Combination with Androgen-Targeted Therapies in Prostate Cancer.

Androgen receptor targeting remains the primary therapeutic strategy in prostate cancer, encompassing androgen biosynthesis inhibitors and androgen receptor antagonists. While both androgen-receptor-positive and "castration-resistant" prostate cancer are responsive to these approaches, the development of resistance is an almost inevitable outcome leading to the castration-resistant form of the disease. Given that "cytoprotective" autophagy is considered to be a predominant mechanism of resistance to various chemotherapeutic agents as well as to radiation in the cancer literature, the purpose of this review is to evaluate whether autophagy plays a central role in limiting the utility of androgen deprivation therapies in prostate cancer. Unlike most of our previous reports, where multiple functional forms of autophagy were identified, making it difficult if not impossible to propose autophagy inhibition as a therapeutic strategy, the cytoprotective form of autophagy appears to predominate in the case of androgen deprivation therapies. This opens a potential pathway for improving the outcomes for prostate cancer patients once effective and reliable pharmacological autophagy inhibitors have been developed.

SAT634 The Androgen Receptor Does Not Directly Regulate The Transcription Of DNA Damage Response Genes

Abstract Disclosure: S. Hasterok: None. T.G. Scott: None. D.G. Roller: None. A. Spencer: None. A.B. Dutta: None. K. Sathyan: None. D.E. Frigo: None. M.J. Guertin: None. D. Gioeli: None. The clinical success of combined androgen deprivation therapy (ADT) and radiation therapy (RT) in prostate cancer (PCa) created interest in understanding the mechanistic links between androgen receptor (AR) signaling and the DNA damage response (DDR). Convergent data have led to a model where AR both regulates, and is regulated by, the DDR. Integral to this model is that the AR regulates the transcription of DDR genes both at steady state and in response to ionizing radiation (IR). In this study, we sought to determine which immediate transcriptional changes are induced by IR in an AR-dependent manner. Using PRO-seq to quantify changes in nascent RNA transcription in response to IR, the AR antagonist enzalutamide, or the combination of the two, we find that enzalutamide treatment significantly decreased expression of canonical AR target genes but had no effect on DDR gene sets in PCa cells. Surprisingly, we also found that the AR is not a primary regulator of DDR genes either in response to IR or at steady state in asynchronously growing PCa cells. Our data indicate that the clinical benefit of ADT and RT is not due to the direct regulation of DDR gene transcription by AR and that the clinical benefit of this therapeutic combination is instead likely due to both treatments independently reducing tumor cell fitness. Presentation: Saturday, June 17, 2023

Targeted Therapy for Cancers: From Ongoing Clinical Trials to FDA-Approved Drugs.

The development of targeted therapies has revolutionized cancer treatment, offering improved efficacy with reduced side effects compared with traditional chemotherapy. This review highlights the current landscape of targeted therapy in lung cancer, colorectal cancer, and prostate cancer, focusing on key molecular targets. Moreover, it aligns with US Food and Drug Administration (FDA)-approved drugs and drug candidates. In lung cancer, mutations in the epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) gene rearrangements have emerged as significant targets. FDA-approved drugs like osimertinib and crizotinib specifically inhibit these aberrant pathways, providing remarkable benefits in patients with EGFR-mutated or ALK-positive lung cancer. Colorectal cancer treatment has been shaped by targeting the vascular endothelial growth factor (VEGF) and EGFR. Bevacizumab and cetuximab are prominent FDA-approved agents that hinder VEGF and EGFR signaling, significantly enhancing outcomes in metastatic colorectal cancer patients. In prostate cancer, androgen receptor (AR) targeting is pivotal. Drugs like enzalutamide, apalutamide, and darolutamide effectively inhibit AR signaling, demonstrating efficacy in castration-resistant prostate cancer. This review further highlights promising targets like mesenchymal-epithelial transition (MET), ROS1, BRAF, and poly(ADP-ribose) polymeras (PARP) in specific cancer subsets, along with ongoing clinical trials that continue to shape the future of targeted therapy.

Peptides disrupting TM4SF3 interaction with AR or AR-V7 block prostate cancer cell proliferation.

Androgen receptor (AR) plays a vital role in the development and progression of prostate cancer from the primary stage to the usually lethal stage known as castration-resistant prostate cancer (CRPC). Constitutively active AR splice variants (AR-Vs) lacking the ligand-binding domain are partially responsible for the abnormal activation of AR and may be involved in resistance to AR-targeting drugs occurring in CRPC. There is increasing consensus on the potential of drugs targeting protein-protein interactions. Our lab has recently identified transmembrane 4 superfamily 3 (TM4SF3) as a critical interacting partner for AR and AR-V7 and mapped the minimal interaction regions. Thus, we hypothesized that these interaction domains can be used to design peptides that can disrupt the AR/TM4SF3 interaction and kill prostate cancer cells. Peptides TA1 and AT1 were designed based on the TM3SF3 or AR interaction domain, respectively. TA1 or AT1 was able to decrease AR/TM4SF3 protein interaction and protein stability. Peptide TA1 reduced the recruitment of AR and TM4SF3 to promoters of androgen-regulated genes and subsequent activation of these AR target genes. Peptides TA1 and AT1 were strongly cytotoxic to prostate cancer cells that express AR and/or AR-V7. Peptide TA1 inhibited the growth and induced apoptosis of both enzalutamide-sensitive and importantly enzalutamide-resistant prostate cancer cells. TA1 also blocked the migration and malignant transformation of prostate cancer cells. Our data clearly demonstrate that using peptides to target the important interaction AR has with TM4SF3 provides a novel method to kill enzalutamide-resistant prostate cancer cells that can potentially lead to new more effective therapy for CRPC.

Development and Validation of a New BAG-1L–Specific Antibody to Quantify BAG-1L Protein Expression in Advanced Prostate Cancer

BCL-2–associated athanogene-1L (BAG-1L) is a critical co-regulator that binds to and enhances the transactivation function of the androgen receptor, leading to prostate cancer development and progression. Studies investigating the clinical importance of BAG-1L protein expression in advanced prostate cancer have been limited by the paucity of antibodies that specifically recognize the long isoform. In this study, we developed and validated a new BAG-1L–specific antibody using multiple orthogonal methods across several cell lines with and without genomic manipulation of BAG-1L and all BAG-1 isoforms. Following this, we performed exploratory immunohistochemistry to determine BAG-1L protein expression in normal human, matched castration-sensitive prostate cancer (CSPC) and castration-resistant prostate cancer (CRPC), unmatched primary and metastatic CRPC, and early breast cancer tissues. We demonstrated higher BAG-1L protein expression in CRPC metastases than in unmatched, untreated, castration-sensitive prostatectomies from men who remained recurrence-free for 5 years. In contrast, BAG-1L protein expression did not change between matched, same patient, CSPC and CRPC biopsies, suggesting that BAG-1L protein expression may be associated with more aggressive biology and the development of castration resistance. Finally, in a cohort of patients who universally developed CRPC, there was no association between BAG-1L protein expression at diagnosis and time to CRPC or overall survival, and no association between BAG-1L protein expression at CRPC biopsy and clinical outcome from androgen receptor targeting therapies or docetaxel chemotherapy. The limitations of this study include the requirement to validate the reproducibility of the assay developed, the potential influence of pre-analytical factors, timing of CRPC biopsies, relatively small patient numbers, and heterogenous therapies on BAG-1L protein expression, and the clinical outcome analyses performed. We describe a new BAG-1L–specific antibody that the research community can further develop to elucidate the biological and clinical significance of BAG-1L protein expression in malignant and nonmalignant diseases.

Discovery of BWA-522, a First-in-Class and Orally Bioavailable PROTAC Degrader of the Androgen Receptor Targeting N-Terminal Domain for the Treatment of Prostate Cancer.

We report small molecular PROTAC compounds targeting the androgen receptor N-terminal domain (AR-NTD), which were obtained by tethering AR-NTD antagonists and different classes of E3 ligase ligands through chemical linkers. A representative compound, BWA-522, effectively induces degradation of both AR-FL and AR-V7 and is more potent than the corresponding antagonist against prostate cancer (PC) cells in vitro. We have shown that the degradation of AR-FL and AR-V7 proteins by BWA-522 can suppress the expression of AR downstream proteins and induce PC cell apoptosis. BWA-522 achieves 40.5% oral bioavailability in mice and 69.3% in beagle dogs. In a LNCaP xenograft model study, BWA-522 was also proved to be an efficacious PROTAC degrader, resulting in 76% tumor growth inhibition after oral administration of a dose of 60 mg/kg. This study indicates that BWA-522 is a promising AR-NTD PROTAC for the treatment of AR-FL- and AR-V7-dependent tumors.

IU1 and enzalutamide combination yields synergistic effects on castration-resistant prostate cancer.

Androgen deprivation therapy (ADT) is one of the main treatment modalities for prostate cancer (PCa); however, almost all patients treated with ADT eventually progress into castration-resistant PCa (CRPC). Although second-generation androgen receptor (AR) antagonists, such as enzalutamide, have been approved for CRPC treatment, AR signaling in CRPC cells is reactivated through multiple mechanisms, resulting in resistance to treatment and tumor progression with a very poor prognosis. The present study aimed to explore the anticancer effect of a treatment combining AR antagonist enzalutamide with AR degrader IU1 on PCa cells. The joint effects of enzalutamide and IU1 on PCa cell proliferation and apoptosis and associated cell signaling were evaluated in vitro. Mechanistically, the ubiquitination level and half-life of AR were examined under the combination treatment. The binding of IU1 and enzalutamide to AR was further verified using cellular thermal shift analysis and isothermal dose-response curve fingerprinting. The combination of IU1 and three AR antagonists showed synergistic effects in different prostate cell lines. IU1 and enzalutamide synergistically promoted the degradation of AR and AR-V7 proteins, as well as suppressed the expression levels of AR and AR-V7 downstream target genes at the transcriptional and protein levels. The combination also synergistically blocked the PCa cell cycle and promoted apoptosis in PCa cell lines. Mechanistically, the combination promoted increased levels of AR ubiquitination. In CRPC cell lines and in the presence of increased androgen concentrations, enzalutamide was still able to bind AR competitively with androgens, reducing the stability of AR and thus promoting the degradation effect of IU1 on AR, synergistically producing an inhibitory effect on PCa cells. Taken together, our findings suggest that the combination of AR degrader and enzalutamide potentially represents a new therapeutic strategy for CRPC.

Approaches to Prevent and Manage Cardiovascular Disease in Patients Receiving Therapy for Prostate Cancer.

Prostate cancer (PCa) is amongst the most common cancers in men worldwide. Cardiovascular (CV) risk factors and CV disease (CVD) are common comorbidities in this patient population, posing a challenge for PCa-directed therapies which can cause or worsen CVRFs and CVDs. Herein, we summarize the approaches to prevent and manage CVD in patients with PCa receiving therapy. While patients with locally advanced and metastatic PCa benefit from hormonal therapy, these treatments can potentially cause CV toxicity. Androgen receptor targeting therapies, such as androgen deprivation therapy (ADT), can induce metabolic changes and directly impact cardiovascular function, thereby reducing cardiorespiratory fitness and increasing CV mortality. Moreover,more than half of the PCa patients have poorly controlled CV risk factors at baseline. Hence, there is an urgent need to address gaps in preventing and managing CVD in PCa patients. Screening and optimizing CV risk factors and CVD in patients undergoing ADT are essential to reduce CV mortality, the leading non-cancer cause of death in PCa survivors. The risk of CV morbidity and mortality can be further mitigated by considering the patient's cardiovascular risk profile when deciding the choice and duration of ADT. A multidisciplinary team-based approach is crucial to achieve the best outcomes for PCa patients undergoing therapy.

Targeting the Androgen Signaling Axis in Prostate Cancer.

Activation of the androgen receptor (AR) and AR-driven transcriptional programs is central to the pathophysiology of prostate cancer. Despite successful translational efforts in targeting AR, therapeutic resistance often occurs as a result of molecular alterations in the androgen signaling axis. The efficacy of next-generation AR-directed therapies for castration-resistant prostate cancer has provided crucial clinical validation for the continued dependence on AR signaling and introduced a range of new treatment options for men with both castration-resistant and castration-sensitive disease. Despite this, however, metastatic prostate cancer largely remains an incurable disease, highlighting the need to better understand the diverse mechanisms by which tumors thwart AR-directed therapies, which may inform new therapeutic avenues. In this review, we revisit concepts in AR signaling and current understandings of AR signaling-dependent resistance mechanisms as well as the next frontier of AR targeting in prostate cancer.

Spermine is a natural suppressor of AR signaling in castration-resistant prostate cancer

In castration-resistant prostate cancer (CRPC), clinical response to androgen receptor (AR) antagonists is limited mainly due to AR-variants expression and restored AR signaling. The metabolite spermine is most abundant in prostate and it decreases as prostate cancer progresses, but its functions remain poorly understood. Here, we show spermine inhibits full-length androgen receptor (AR-FL) and androgen receptor splice variant 7 (AR-V7) signaling and suppresses CRPC cell proliferation by directly binding and inhibiting protein arginine methyltransferase PRMT1. Spermine reduces H4R3me2a modification at the AR locus and suppresses AR binding as well as H3K27ac modification levels at AR target genes. Spermine supplementation restrains CRPC growth invivo. PRMT1 inhibition also suppresses AR-FL and AR-V7 signaling and reduces CRPC growth. Collectively, we demonstrate spermine as an anticancer metabolite by inhibiting PRMT1 to transcriptionally inhibit AR-FL and AR-V7 signaling in CRPC, and we indicate spermine and PRMT1 inhibition as powerful strategies overcoming limitations of current AR-based therapies in CRPC.

Abstract A056: AR/FOXA1-mediated active gene repression as a mechanism of prostate carcinogenesis

Abstract The identity of the prostate gland is defined by transcription factors (TF) like the androgen receptor (AR), FOXA1, and NKX3.1 that bind regulatory elements early in development to activate the lineage gene program. For instance, KLK3, is a canonical target gene activated by AR. While the mechanistic interactions between pioneer factors, chromatin remodelers, and epigenetic proteins required for gene activation is well understood, repressive activity of lineage-defining TFs remain largely uncharacterized. Here, we document and mechanistically describe the active, repressive transcriptional functions of AR and FOXA1 in the context of prostate tumorigenesis.We identified a shared repertoire of repressed gene targets of AR and FOXA1 by using transcriptomic profiles (RNA-seq) of PCa cells treated with dihydrotestosterone (DHT) or TF targeting siRNA. Chromatin binding of AR and/or FOXA1 (ChIPseq) at cis-regulatory elements (dCREs) within the gene’s topologically-associated domain was used as primary evidence for direct regulation. Here, the KLK3 and DEPTOR gene loci emerged as candidate-activated or repressed AR/FOXA1 targets in PCa cells. DEPTOR, a tumor suppressor gene, negatively regulates the mTORC1/2 complexes by inhibiting their kinase activity. In contrast to the passive model of repression, where sequestration of co-activators ensues in transcriptional down-regulation of genes, we found ligand-bound AR and FOXA1 bind CREs within DEPTORs’ TAD establishing looping interactions (H3K3me3 HiChIP-seq) with the DEPTOR gene promoter. Functional inactivation of AR or FOXA1 led to a 2-4 fold upregulation of DEPTOR in VCaP, LNCaP, and 22RV1 cells. Instead, DHT-stimulation of AR led to DEPTOR downregulation. To assess the rapidness of this effect, we used a SWI/SNF ATPase PROTAC, AU15330, which triggers instant compaction of CREs and dislodges AR/FOXA1 from the chromatin. Treatment of PCa cells with AU15330 for 4 hours led to an immediate and significant upregulation of DEPTOR, substantiating the direct transcriptional repression by the AR/FOXA1 complex. Consistently, AU-15330 treatment also abolished FOXA1 and AR binding and 3D loop formation into the DEPTOR promoter. Using an orthogonal genetic approach, CRISPR-KRAB-targeted heterochromatinization of the AR/FOXA1 repressive CREs led to increased production of the nascent DEPTOR transcript. Finally, monoclones devoid of the CRE had elevated DEPTOR levels. Altogether, our findings position DEPTOR as an actively repressed target of the AR/FOXA1 transcriptional complex, suggesting the “silencer” duties of driver TF oncogenes to play a critical role in prostate tumorigenesis. Furthermore, the repertoire of activated and repressed gene targets identified in this study serve as exciting loci to study differences in the co-factor machinery and/or other cis or trans-attributes of the encompassing TADs that regulate downstream transcriptional outcomes. We posit the active mode of gene repression plays a driver role in prostate carcinogenesis. Citation Format: Sanjana Eyunni, Abhijit Parolia, Eleanor Young, James George, Mustapha Jaber, Lanbo Xiao, Fengyun Su, Rui Wang, Xuhong Cao, Arul Chinnaiyan. AR/FOXA1-mediated active gene repression as a mechanism of prostate carcinogenesis [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr A056.

Abstract A059: Epigenetic remodelling by class I HDAC inhibitors increases response to androgen signalling inhibitors in prostate cancer

Abstract Prostate cancer (PCa) is one of the most prevalent cancers in the male population with approximately 1 in 8 men diagnosed with the disease during their lifetime. The treatment options available varies depending on individual circumstances, with surgery or radiotherapy employed as first-line treatments for locally advanced PCa whilst hormone therapies are employed as the disease progresses toward castrate-resistant prostate cancer. Despite the advances in therapies and initial treatment effectiveness, tumours develop resistance and overcoming this resistance proves a major challenge for the treatment of the disease. Dysregulation of chromatin regulatory proteins and the epigenetic landscape are key factors contributing to the development, progression and persistence of PCa. Histone deacetylases (HDACs) are a family of chromatin-modifying proteins which assemble into various transcriptional repressor complexes and mediate gene repression through the removal of acetyl groups from histone tails, subsequently compacting the chromatin landscape impacting on cell proliferation, transcription, replication and DNA repair. Overexpression of HDACs in prostate cancer has been shown to shift the balance of acetylation, resulting in improper gene silencing. Therefore, we hypothesise that restoration of the acetylation homeostasis through HDAC inhibition is a potential therapy to overcome resistance in PCa. Here, we show that the class I HDAC inhibitor Entinostat as a single agent promotes anti-tumour effects in PCa by impairing cell proliferation and inducing apoptosis in a panel of PCa cell lines. Interestingly, we found that combination with the androgen signalling inhibitors (ASIs), Enzalutamide or Abiraterone, further enhances these anti-tumour effects. In vitro analysis of matched parental and Enzalutamide-/Abiraterone-resistant C4-2B and CWRR-1 cells further revealed an enhanced reduction in cell survival following combined Entinostat and ASIs treatments in the resistant models compared to parental. Genomic and transcriptomic analyses uncovered distinct molecular signatures of these resistant models. Treatment with Entinostat alone downregulated androgen receptor (AR) expression and combination with ASI further suppressed AR expression and downstream AR target genes. Taken together, these results demonstrate the potential for Entinostat to synergise with current standard-of-care therapies to target ASI resistance in PCa. In conclusion, this study provides strong evidence suggesting the effectiveness of class I HDAC inhibition by Entinostat in the treatment of castration-resistant prostate cancer and opens the door for further research into combinatorial therapies in targeting resistance. Citation Format: Rachel McCole, Ben McCullough, Judith M. Manley, Nicholas Forsythe, Simon S. McDade, Melissa LaBonte Wilson. Epigenetic remodelling by class I HDAC inhibitors increases response to androgen signalling inhibitors in prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr A059.

Abstract B008: Tumor-stromal 3D co-cultures to study the role of cancer-associated fibroblasts in the acquisition of androgen-deprivation therapy resistance in prostate cancer

Abstract Introduction and Objective Several studies have shown that cancer-associated fibroblasts (CAFs), the most abundant component in prostate cancer (PCa) microenvironment, promote resistance to androgen deprivation therapies, and metastatic development. The aim of this study is to elucidate the mechanisms of CAF-induced therapy resistance through the establishment of in vitro 3D co-cultures. Methods In this study, the androgen-dependent PNPCa patient-derived xenograft (PDX) model (derived from soft tissue metastasis), and the androgen-independent LAPC9 PDX model (bone metastasis) are used. Epithelial and stromal cells (human and mouse origin, respectively) are separated through magnetic-associated cell sorting to generate PDX-derived organoids and fibroblasts. Fibroblast RNA and protein expression is assessed through RT-qPCR, Western Blot, and Immunofluorescence. Direct 3D co-cultures are obtained by combining fluorescently labelled organoids and fibroblasts in ultra-low attachment plates in defined media. In indirect co-cultures, organoids are cultured in Spherical Plates (Kugelmeiers) with fibroblasts on transwell inserts. Organoid viability is measured after 9 days by CellTiter-Glo 3D Assay. Results PDX-derived fibroblasts express typical CAF genes (e.g. α-smooth muscle actin and Tenascin C), and androgen receptor (AR), both at RNA and protein level. AR protein expression (as well as RNA expression of the AR target gene Fkbp5) is increased in CAFs upon treatment with dyhydrotestosterone (DHT) 10nM, while co-treatment with the AR inhibitor Enzalutamide 10mM abrogates this effect, suggestive of functional AR signaling. These CAFs can organize into tumor/CAF organoid 3D structures upon combination with PDX-derived tumor epithelial cells, providing an in vitro functional model to study tumor-stromal interactions. In indirect (transwell) co-cultures, CAFs increase the viability of the androgen dependent PNPCa organoids, but not that of androgen independent LAPC9. This growth-promoting effect is observed even upon culturing of PNPCa organoids in non-optimal growth conditions, at low DHT concentrations (DHT 0.5nM and 0.25nM versus the standard DHT 1nM). The factors mediating this process will be identified by gene expression profiling of CAFs and organoids in transwell co-cultures and/or monoculture. Conclusions Our data indicate that PCa metastatic cells modify the properties of neighbor stromal cells to support tumorigenesis, since PDX-derived fibroblasts, originally part of the mouse dermal stroma, display CAF features and active AR signaling. 3D co-cultures represent a useful tool to study the tumor-stromal interactions. Our transwell co-culture experiments suggest that CAFs play an important role in supporting the viability and growth of early metastatic androgen dependent PCa cells (PNPCa) by secreting pro-tumorigenic factors. The possibility that CAFs exert different effects depending on the tumor stage setting (early vs advanced) will be subsequently investigated. Citation Format: Francesco Bonollo, Natalie Sampson, George Thalmann, Sofia Karkampouna, Marianna Kruithof-de Julio. Tumor-stromal 3D co-cultures to study the role of cancer-associated fibroblasts in the acquisition of androgen-deprivation therapy resistance in prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B008.

Androgen receptor–specific CD8+ T cells with tumor cell cytotoxicity in patients with prostate cancer in Taiwan.

e17069 Background: Classical androgen receptor (AR) target is the new “tumor-specific” antigen for prostate cancer vaccine development to delay progression and castration-resistant disease. HLA-A2-restricted AR ligand-binding domain (LBD) has been demonstrated to stimulate cytotoxic T lymphocytes (CTL) in HLA-A2+ prostate cancer patients. Although the prevalence of HLA-A2 serotype and LBD-specific CD8+ T cells among Caucasians are known, their frequencies in the Taiwan patients have not been established. In this study, we performed HLA-A2 genotyping, HLA-A2+ LNCaP stimulation of autologous T cell, and CTL tumor cell cytotoxicity from 25 castration-sensitive prostate cancer patients using blood samples collected from a single hospital center. Methods: 20ml whole blood samples are collected in EDTA tube from non-metastatic, castration-sensitive prostate cancer patients. PBMCs are subjected to HLA-A2 allele sequencing, separated by CD3 magnetic bead column, and expanded and activated ex vivo using CD3/CD8 polymeric beads. Autologous T cells are then isolated by CD8 magnetic bead column, stimulated by HLA-A2+ lentivirus-transduced LNCaP (AR+), and targeted against transduced (HLA-A2+) and non-transduced (HLA-A2-) LNCaP (AR+) by Chromium-51 Release Assay. We identified and correlated their frequencies with patient’s age at diagnosis, Gleason grades, PSA level, and family history. Results: A total of 25 blood samples were tested and analyzed for HLA-A2 genotype with 44% (11/25) positive for the HLA-A2 [28% (7/25) heterozygotes, 16% (4/25) homozygotes]. Among the 11 HLA-A2+ patients, 72% (8/11) were HLA-A*02:07 allele, 100% (11/11) CD8+ T cells were successfully stimulated with HLA-A2+ transduced LNCaP (AR+) and 45% (5/11) patients demonstrated HLA-A2+ AR-specific CTL tumor cell lysis. No clinical association with patient age (54-86 y.o.), Gleason grades (6-9), PSA level (3.84-62.8 ng/ml), and family history (1/25). Conclusions: In this single hospital center study, we observed a similar prevalence of HLA-A2 alleles in Taiwan prostate cancer patient cohort with a predominant HLA-A2*02:07 allele, and higher frequencies of HLA-A2-restricted CD8+ T cell stimulation and HLA-A2+ AR-specific tumor cell cytotoxicity. Our findings support the application of AR LBD as tumor antigen for prostate cancer vaccine development for Taiwan prostate cancer patients.

Network pharmacology analysis of the pharmacological mechanism of Artemisia lavandulaefolia DC. in rheumatoid arthritis

ObjectiveThe traditional She medicine is a notable type of traditional Chinese medicine, which has been applied for a long history despite the lack of sufficient mechanistic understanding. Our study revealed the possible molecular mechanism of sesquiterpene 5α-Hydroxycostic acid, active ingredient of traditional She medicine Artemisia lavandulaefolia DC., in the treatment of rheumatoid arthritis (RA). MethodsRA-fibroblast like synoviocytes (RA-FLSs) were treated with 5α-Hydroxycostic acid, Anthemidin, and methotrexate (MTX). CCK-8 and ELISA were used to measure the resultant viability of RA-FLSs and to quantify pro-inflammatory cytokines. Target genes of 5α-Hydroxycostic acid and Anthemidin, RA-related differentially expressed genes, and RA-related genes were retrieved by bioinformatics analyses, results of which were further intersected to identify candidate genes. The protein-protein interaction network was constructed to develop the pharmacophore model. The molecular docking was simulated to determine the core target androgen receptor (AR) for subsequent molecular mechanism investigation in vitro. ResultsThe 5ɑ-Hydroxycostic acid, Anthemidin, or MTX of different concentrations inhibited the viability of RA-FLSs, and downregulated the levels of proinflammatory cytokines. The pharmacophore model and molecular docking of 10 candidate targets with 5α-Hydroxycostic acid were successfully established. In vitro experiments provided evidence confirming that 5α-Hydroxycostic acid elevated AR expression to inhibit inflammatory responses of RA-FLSs and degradation of extracellular matrix. ConclusionTherefore, this study reveals the active ingredient sesquiterpene 5α-Hydroxycostic acid of traditional She medicine Artemisia lavandulaefolia DC., and illustrates potential molecular mechanism in RA treatment by upregulating AR expression. This study is the first to report the effect of the active ingredient sesquiterpenes in traditional She medicine A.lavandulaefolia DC on RA and elucidate the underlying molecular mechanism associated with up-regulated AR expression. This study provides new insights into the mechanistic understanding of traditional She medicine in the treatment of RA.

Inhibition of Wnt/β-catenin pathway overcomes therapeutic resistance to abiraterone in castration-resistant prostate cancer.

Abiraterone acetate has been clinically approved for the treatment of patients with advanced-stage prostate cancer. It reduces testosterone production by blocking the enzyme cytochrome P450 17 alpha-hydroxylase. Despite improved survival outcomes with abiraterone, almost all patients develop therapeutic resistance and disease recurrence, progressing to a more aggressive and lethal phenotype. Bioinformatics analyses predicted activation of canonical Wnt/β-catenin and involvement of stem cell plasticity in abiraterone-resistant prostate cancer. Increased expression of androgen receptor (AR) and β-catenin and their crosstalk causes activation of AR target genes and regulatory networks for which overcoming acquired resistance remains a major challenge. Here we show that co-treatment with abiraterone and ICG001, a β-catenin inhibitor, overcomes therapeutic resistance and significantly inhibited markers of stem cell and cellular proliferation in abiraterone-resistant prostate cancer cells. Importantly, this combined treatment abrogated the association between AR and β-catenin; diminished SOX9 expression from the complex more prominently in abiraterone-resistant cells. In addition, combined treatment inhibited tumor growth in an in vivo abiraterone-resistant xenograft model, blocked stemness, migration, invasion, and colony formation ability of cancer cells. This study opens new therapeutic opportunity for advanced-stage castration-resistant prostate cancer patients.

GC-MS Characterization and Computational Assessment of Phytochemicals in Heliotropium indicum Ethanolic Leaves Extract

Heliotropium indicum (Indian heliotrope) belongs to family Boraginaceae, which has wide ethnopharmacological applications such as antiulcer, antirheumatism and anti-cholera. The aim of this study was to characterize the phytochemicals in H. indicum ethanolic leaves extract using Gas chromatography-mass spectrometry (GC-MS), and computationally assessed its pharmacokinetics profiles, molecular targets and infer overall medicinal application. The results showed twenty-nine (29) identified constituents of H. indicum in its ethanolic leaves extract from GC-MS, many of which are poorly soluble and have low gastrointestinal absorption (GIA). However, some of them are soluble with high GIA and could permeate blood brain barrier (BBB). The results showed that (+)-Isomenthol, and Ergost-22-en-3-ol are the two most active constituents of ethanolic leaves extract of H. indicum; targeting androgen receptor (AR) and transient receptor potential cation channel subfamily M member 8 (TRPM8), which have implication in prostate cancer. Thus, H. indicum plant extract is a potential anti-PCa medicinal plants. However, there is need for in vivo and in vitro studies to validate these results, hence promoting these active compounds optimization and clinical evaluations in H. indicum.