PCa Cell Lines Research Articles

CDR1as/miR-7-5p/IGF1R axis contributes to the suppression of cell viability in prostate cancer

Abstract Background Prostate cancer is the most frequently diagnosed male cancer and the fifth highest cause of cancer mortality in men. CDR1as has played an essential role in the growth of several malignancies. However, its significance in the progression of prostate cancer has not been investigated. We aimed to investigate the role and mechanism of CDR1as in the development of prostate cancer and identify a new target for diagnostics and treatment. Methods CDR1as siRNA and miR-7-5p mimic were transfected into PC3 and DU145 PCa cell lines and their effects on cellular processes were investigated. Cell viability was measured by WST-8 assay. The role of CDR1as and/or miR-7-5p on PCa cell migration was detected using the scratch-wound assay. The apoptotic capacity of the cells was evaluated using the Caspase-3 kit. The potential targets of miR-7-5p were defined via in silico tools. mRNA and protein expression levels of IGF1R and EIF4E were detected by qRT-PCR and western blot assays, respectively. The matching between miR-7-5p and IGF1R was defined via luciferase reporter assay. Results Inhibiting CDR1as or restoring miR-7-5p reduced prostate cancer cell proliferation and migration while increasing apoptosis. Silencing CDR1as elevated the expression of miR-7-5p while decreasing IGF1R. Conclusions CDR1as functions as a miR-7-5p sponge, increasing IGF1R expression and promoting tumor development.

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.

CircDUSP22 Attenuates the Ferroptosis of Prostate Cancer Cells via miR-18a-5p/SLC7A11/GPX4 Signaling.

According to current worldwide cancer data, Prostate Cancer (PC) ranks as the second most common type of cancer and is the fifth leading cause of cancer-related mortality among men worldwide. PC in China has the 10th highest number of new cases and the 13th highest fatality rate, both of which show an ongoing annual increase. One of the significant challenges with prostate cancer is the difficulty in early detection, often resulting in diagnosis at intermediate or late stages, complicating treatment. Although hormonal therapy is initially successful in controlling the progression of prostate cancer, almost all tumors that respond to hormones eventually transform into Castration-resistant Prostate Cancer (CRPC) within 18-24 months of hormonal therapy. This poses clinical difficulties due to an absence of successful therapeutic approaches. Therefore, understanding the fundamental mechanisms of prostate cancer development, identifying effective therapeutic targets, and discovering reliable molecular biomarkers are crucial objectives. CircRNA expression in plasma was assessed in 4 samples obtained from patients with Benign Prostatic Hyperplasia (BPH), and PC was detected through microarray probes. Statistical analysis of the expression of circDUSP22 and clinicopathological features was conducted. The investigation of target genes was conducted using luciferase reporter assays and bioinformatics analysis. The expression levels of circDUSP22, miR-18a-5p, and Solute Carrier Family 7 member 11 (SLC7A11) were assessed using a quantitative Real-time Polymerase Chain Reaction (qRT-PCR) assay. Cell invasion, migration, colony formation, and proliferation were evaluated using Transwell, wound healing, colony formation, and CCK-8 assays, respectively. RNA Immunoprecipitation (RIP) and dual-luciferase reporter assays were used to examine the connections among circDUSP22, miR-18a-5p, and SLC7A11. The impact of circDUSP22 on the expression of ferroptosis-related proteins, specifically SLC7A11, as well as its effects on Fe2+ and ROS were also examined. In both plasma samples and PCa cell lines, there was a substantial elevation of circDUSP22 and SLC7A11 expression and a decline in miR-18a-5p expression. Suppression of circDUSP22 significantly impeded the migration, invasion, and proliferation of PC cells in vitro. The target gene of miR-18a-5p, SLC7A11, was found to be upregulated as an effect of circDUSP22's competitive binding to miR-18a-5p. Cellular experiments demonstrated that interference with circDUSP22 expression in DU145 and PC-3 cells led to increased ferroptosis and decreased SLC7A11 expression. The modulation of prostate cancer cell proliferation was reversed by either overexpressing SLC7A11 or inhibiting miR-18a-5p in response to the silencing of circDUSP22. The circDUSP22 has been found to have a substantial effect on the development of ferroptosis in PC. It has been observed to influence the formation and evolution of this disorder by affecting the miR-18a-5p/SLC7A11 signaling pathway.

Hsa_circ_0070440 mediates the prognosis and progress of human prostate cancer.

This study was designed to explore whether hsa_circ_0070440 was dysregulated in prostate cancer (PCa), and assess the effects of hsa_circ_0070440 alteration on PCa prognosis and cell function. The expression levels of hsa_circ_0070440 were assessed in PCa tissues and cell lines. After the classification of patients with PCa based on mean hsa_circ_0070440 level in 138 cases, Chi-square test and survival analyses (Kaplan-Meier method and multivariable Cox proportional hazards analysis) were performed to assess the predictive value of hsa_circ_0070440 in treatment failure (TTF), time to PSA progression (TTPP) and overall survival time. To examine the function of hsa_circ_0070440 in PCa cells, 22Rv1 and C4-2B cells were used for CCK-8 proliferation and Transwell migration assays. Hsa_circ_0070440- and TXNDC5-specific bindings with miR-382/383-5p were validated by bioinformatic analysis and luciferase gene reporter assay. An increased expression of hsa_circ_0070440 was found in PCA tissues and cell lines, associated with clinical T stage (p=0.021) and lymph node metastasis. Hsa_circ_0070440 predicted poor overall survival, TTPP, and TTF, acting as independent prognostic factors for overall survival, TTPP, and TTF in patients with PCa. Knockdown of hsa_circ_0070440 inhibited cell proliferation and migration in vitro. Furthermore, hsa_circ_0070440 could sponge miR-382/383-5p. TXNDC5 was a common target gene for miR-382/383-5p in PCa cells. This study demonstrated that hsa_circ_0070440 can predict the prognosis of PCa patients. Hsa_circ_0070440 can facilitate the proliferation and migration of PCa cells, possibly by sponging miR-382/383-5p.

Interference with mitochondrial metabolism could serve as a potential therapeutic strategy for advanced prostate cancer.

Metabolic reprogramming has been defined as a hallmark of malignancies. Prior studies have focused on the single nucleotide polymorphism (SNP) of POLG2 gene, which is reportedly responsible for encoding mitochondrial DNA genes and is implicated in the material and energy metabolism of tumor cells, whereas its function in prostate cancer has been elusive. Gene expression profile matrix and clinical information were downloaded from TCGA (The Cancer Genome Atlas) data portal, and GSE3325 and GSE8511 were retrieved from GEO (Gene Expression Omnibus) database. We conducted analysis of the relative expression of POLG2, clinical characterization, survival analysis, GO / KEGG and GSEA (Gene Set Enrichment Analysis) enrichment analysis in R and employed STRING portal to acquaint ourselves with the protein-protein interaction (PPI). IHC (Immunohistochemical) profiles of POLG2 protein between normal and cancerous tissues were consulted via HPA (Human protein atlas) database and the immunohistochemical POLG2 were verified between para-cancerous and cancerous tissues in tissue array. At the cellular level, Mitochondrial dysfunction assay, DNA synthesis test, wound healing assay, and invasion assay were implemented to further validate the phenotype of POLG2 knockdown in PCa cell lines. RT-qPCR and western blotting were routinely adopted to verify variations of molecular expression within epithelial mesenchymal transition (EMT). Results showed that POLG2 was over-expressed in most cancer types, and the over-expression of POLG2 was correlated with PCa progression and suggested poor OS (Overall Survival) and PFI (Progress Free Interval). Multivariate analysis showed that POLG2 might be an independent prognostic factor of prostate cancer. We also performed GO/KEGG, GSEA analysis, co-expression genes, and PPI, and observed the metabolism-related gene alterations in PCa. Furthermore, we verified that POLG2 knockdown had an inhibitory effect on mitochondrial function, proliferation, cell motility, and invasion, we affirmed POLG2 could affect the prognosis of advanced prostate cancer via EMT. In summary, our findings indicate that over-expressed POLG2 renders poor prognosis in advanced prostate cancer. This disadvantageous factor can serve as a potential indicator, making it possible to target mitochondrial metabolism to treat advanced prostate cancer.

Abstract 1274: Investigating PLOD2 as a therapeutic target to overcome metastasis in radiorecurrent prostate cancer

Abstract Prostate cancer (PCa) is the second most common cancer in males, with 1 in 8 men developing the disease in their lifetime. For PCa, a common treatment strategy is external beam radiation therapy to the prostate. However, when cancer recurs (radiorecurrent PCa), it often behaves aggressively by invading into surrounding organs or spreading distantly. Radiorecurrent PCa metastasis is therefore a significant cause of morbidity and mortality that must be overcome to improve survival of advanced PCa patients. Proteomic analysis revealed the procollagen enzyme Lysyl Hydroxylase 2 (PLOD2) to be upregulated in our radiorecurrent, and highly aggressive, conventionally fractionated DU145 (DU145-CF) PCa cell line. Given its established function as a mediator of invasion in various other cancers, we sought to characterize the role of PLOD2 in the aggressive phenotype of our radiorecurrent PCa cells. Bioinformatic analysis of clinical data revealed PLOD2 genomic amplification to be significantly associated with biochemical recurrence in PCa patients. Upon further examination in vitro, it was revealed that PLOD2 knockdown significantly reduces matrigel invasion and migration in our radiorecurrent DU145-CF cell line, in addition to numerous other PCa cell lines, including primary cells we derived directly from PCa patients. Using the in vivo chick Chorioallantoic Membrane (CAM) model, we confirmed that PLOD2 knockdown significantly reduces the ability of DU145-CF cells to extravasate from the CAM vasculature into the surrounding stroma, a critical step of the metastatic cascade. To explore mechanisms of metastatic cellular reprogramming downstream of PLOD2, RNA sequencing of DU145-CF cells was conducted; a total of 681 genes were discovered to be dysregulated by PLOD2 knockdown, with their functional analysis suggesting changes in cellular metabolism and respiration. Finally, since PLOD2 is known to be regulated by hypoxia-induced protein HIF1α, we explored whether PLOD2 expression could be inhibited by the HIF1α inhibitor, PX-478. Treatment with PX-478 reduced both HIF1α and PLOD2 protein expression, and significantly reduced invasion, migration, and in vivo extravasation in DU145-CF cells, thereby indicating its potential as a pharmacological inhibitor of HIF1α-associated PLOD2 in radiorecurrent PCa. Together, our results demonstrate for the first time the role of PLOD2 in radiorecurrent PCa invasiveness, and point towards its potential as a therapeutic target to reduce metastasis and improve survival outcomes in PCa patients. Citation Format: Gavin Frame, Hon Leong, Roni Haas, Xiaoyong Huang, Jessica Wright, Paul C. Boutros, Thomas Kislinger, Stanley K. Liu. Investigating PLOD2 as a therapeutic target to overcome metastasis in radiorecurrent prostate cancer [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 1274.

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 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 466: microRNA regulators of neuroendocrine differentiation in metastatic castration-resistant prostate cancer

Abstract Therapy-induced neuroendocrine prostate cancer (NEPC), an extremely aggressive variant of castration-resistant prostate cancer (CRPC), is increasing in incidence with the widespread use of highly potent androgen receptor (AR)-pathway inhibitors (APIs) via a reversible trans-differentiation process, referred to as neuroendocrine differentiation (NED). The molecular basis of NED is not completely understood leading to a lack of effective molecular markers for its diagnosis. We hypothesized that alterations in key miRNAs drive NED, leading to lineage switching and emergence of NEPC. The aims of our study are: (i) identify key miRNA alterations that occur as PCa cells undergo neuroendocrine differentiation; (ii) develop a miRNA-based classifier for predicting/diagnosing NEPC; (iii) understand the functional role of key miRNA alterations. To systematically investigate the key miRNAs alterations driving therapy induced NED, we performed small RNA-NGS in a retrospective cohort of human metastatic CRPC clinical samples + PDX models with adenocarcinoma features (CRPC-adeno) vs those with neuroendocrine features (CRPC-NE). Further, with the application of machine learning algorithms to sequencing data, we trained a ‘miRNA classifier’ that could robustly classify ‘CRPC-NE’ from ‘CRPC-Adeno’ cases. The performance of classifier was validated in additional cohorts of mCRPC patients acquired from independent sites by employing single model prediction algorithm. We further sought to understand the functional role of these miRNAs by overexpessing in PCa cell lines followed by functional assays. In vivo xenograft studies were performed using PC3 cells overexpressing miR-28/control miRNA. We demonstrate for the first time, that lineage switching to NE states is accompanied by key miRNA alterations. Our analysis, measured using receiver operating characteristic (ROC) curves, demonstrated an area under the curve (AUC) value of 0.8318, confirming the robustness of our classifier in distinguishing CRPC-NE from CRPC-Adeno. Furthermore, we identified a select group of 5 miRNAs that were pivotal in distinguishing between these two prostate cancer subtypes. We focused on miR-28-3p, little studied miRNA in prostate cancer. Our in vitro and in vivo data with prostate cancer cell lines and xenograft model suggests that miR-28-3p acts as a tumor suppressor miRNA in advanced stage prostate cancer. We further found mesenchymal gene Vimentin to be a direct miR-28-3p target. We propose that loss of miR-28-3p promotes epithelial-to-mesenchymal transition (EMT), thereby favoring NED. Our study has important clinical implications and transformative potential as our 'miRNA classifier' can be used as a molecular tool to stratify mCRPC patients into those with/without NED and guide treatment decisions. Further, we identify novel miRNA NED drivers that can be exploited for NEPC therapeutic targeting. Citation Format: Diana Asante, Sandip Nathani, Tae Jin Lee, Ashok Sharma, Sharanjot Saini. microRNA regulators of neuroendocrine differentiation in metastatic castration-resistant prostate cancer [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 466.

Abstract 7116: Targeting the CBP/p300 axis in lethal prostate cancer impacts DNA repair

Abstract Prostate cancer (PCa) is the 2nd leading cause of cancer related deaths in US men. PCa is an androgen dependent disease driven by the androgen receptor (AR). Currently, androgen-deprivation therapy (ADT) is the standard of care first-line therapy for metastatic PCa. Resistance to ADT uniformly leads to lethal disease, termed castration-resistant prostate cancer (CRPC). Thus, there is an unmet clinical need to identify and develop novel strategies to treat CRPC. CBP/p300 are potent co-activators for AR. High expression of CBP/p300 is associated with locally advanced disease and castration resistant function of AR, resulting in poor patient outcomes and further highlighting the need to discern the role of CBP/p300 to potentially develop therapeutic targets for precision medicine. Previous studies have relied on non-specific compounds and genetic silencing to target CBP/p300. In this study, CBP/p300 mediated bromodomain activity is targeted by CCS1477 (inobrodib), a first-in-class bromodomain inhibitor developed by Cell Centric. CCS1477 treatment demonstrated effective inhibition in growth and clonogenicity assays. Inhibition of the CBP/p300 bromodomain with CCS1477 resulted in significant downregulation of AR-FL, AR-V7, and its targets’ mRNA expression in addition to inhibition of associated factors such as c-MYC and its downstream targets in PCa cell lines as well as patient derived xenograft (PDX) models. This study shows that CBP and p300 are highly expressed and correlate closely with AR gene expression and AR activity score in primary PCa and CRPC patient samples. The clinical significance of CBP/p300 expression in PCa has been investigated via elucidation of CBP/p300 transcriptional reprogramming and its role in DNA damage response (DDR) pathways. Specifically, findings revealed that CBP/p300 bromodomain suppression sensitizes to AR-dependent DNA-repair. Transcriptional mapping identified CBP/p300 as regulators of cell proliferation and DNA repair processes, which were functionally confirmed across several PCa model systems. To assess relevance, exogenous challenge with radiation revealed that CBP/p300 are required for AR-mediated DNA repair, and CBP/p300 expression is linked to DNA repair capacity in the clinical setting. Molecular analyses revealed that CBP/p300 facilitate double-strand break (DSB) repair efficiency via homologous recombination (HR) mediated DDR. Congruently, CBP/p300 strongly correlated with HR gene expression in PCa patient tissue. These collective findings reveal that CBP/p300 govern repair of DNA DSBs by regulating HR, thus modulating genome integrity and promoting CRPC growth. These studies identify CBP/p300 as a driver of PCa tumorigenesis through coordinated control of critical transcriptional events and lay the groundwork to optimize therapeutic strategies for advanced PCa via CBP/p300 inhibition, potentially in combination with AR-directed therapies. Citation Format: Sumaira Sardar, Lakshmi Ravindranath, Christopher McNair, Saswati N. Chand, Wei Yuan, Denisa Bogdan, Jonathan Welti, Adam Sharp, Matthew Schiewer, Lisa Butler, Johann de Bono, Kris Frese, Nigel Brooks, Neil Pegg, Karen Knudsen, Ayesha A. Shafi. Targeting the CBP/p300 axis in lethal prostate cancer impacts DNA repair [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 7116.

Abstract 2954: Androgen deprivation therapy (ADT) and senescence-associated secretory phenotype (SASP) in vitro: Correlation with SASP in tumor specimens as well as in the serum of patients after ADT

Abstract Introduction: Androgen Deprivation Therapy (ADT) is a highly effective treatment for prostate cancer. However, resistance to ADT develops in most patients, leading to a lethal state of castration-resistant prostate cancer (CRPC). Senescent prostate cancer (SPC) cells can arise after ADT and contribute to therapy resistance. SPCs can restore replicative function and alter the tumor microenvironment through pro-tumorigenic senescence-associated secretory phenotype (SASP). We aimed to characterize changes in SASP in prostate cancer cell lines and serum samples from patients receiving ADT. Methods: SASP factors (Luminex 100/200 System, xMAP Instruments) were analyzed in patients undergoing ADT. To correlate SASP with the sensitivity to ADT, we sought to evaluate the regulation of SASP in vitro using PCa cell lines. The PC3 (AR resistant) and LNCaP (AR sensitive) cell lines were used in the experiments. We performed an analysis of archival tumor tissue (paired) from 18 patients with or without alterations in DNA repair genes (BRCA1, BRCA2, and CDK12). We performed immunohistochemical (IHC) staining of known SASP markers, such as P16, uPAR, gamma-H2AX, and Lamin B1. Results: In a cohort of patients (n=8) with pre and post-ADT matched status, we demonstrate increased levels of SASP factors such as IL-6 (pre-ADT: 1.54±0.24 pg/ml, post-ADT: 5.23±1.3 pg/ml p=0.001), IL-7 (pre-ADT: 3.11±0.6 pg/ml, post-ADT: 13.5±2.7 pg/ml p=0.01), IL-1 alpha (pre-ADT: 1.06±0.3 pg/ml, post-ADT: 15.3±3.5 pg/ml p=0.001), IL-15 (pre-ADT: 15.6±3.1 pg/ml, post-ADT: 37.1±4.8 pg/ml p=0.002), MIF (pre-ADT: 1036±67.6pg/ml, post-ADT: 2362±55.5 pg/ml p=0.003), and IL-15 (pre-ADT: 5±2.1 pg/ml, post-ADT: 37.5±5.1 pg/ml p=0.002). In vitro, the AR-responsive LNCaP cell line, exposed to AR blockade, showed similar findings in upregulating IL-6, IL-7, and IL-15 but not the PC3 cell line. We also demonstrate measurable differences between the expression of u-PAR, gamma-2AX, p16, and loss of Lamin B1 expression in tumor specimens from patients with advanced castration-resistant prostate cancer (n=18). The expression of p16 was significantly upregulated post-treatment irrespective of DDR status (p=0.0417). Other SASP factors showed a trend in upregulation but were insignificant (u-PAR p=0.056, gamma-H2AX p=0.62, Lamin B1 p=0.72) Conclusion: These results provide evidence of systemic increases in SASP-related cytokines following treatment with ADT. The in vitro results suggest that secretion of SASP is promoted by an AR-mediated mechanism. Preliminary results from tumor specimens suggest increased senescence marker p16 expression induced by therapy. Ongoing experiments are further characterizing the senescence markers in prostate tumor specimens and correlated to treatment effect. Citation Format: Maximilian Schwermann, Matthew Hadfield, Shaolei Lu, Praveen Srinivasan, Vida Tajiknia, William MacDonald, Andrew George, Shengliang Zhang, Leiqing Zhang, Kimberly Meza, Andre De Souza, Dragan Golijanin, Elias Hyams, Galina Lagos, Sheldon Holder, Anthony Mega, John Sedivy, Howard Safran, Wafik El-Deiry, Benedito Carneiro. Androgen deprivation therapy (ADT) and senescence-associated secretory phenotype (SASP) in vitro: Correlation with SASP in tumor specimens as well as in the serum of patients after ADT [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 2954.

Abstract 1562: HMGA2 regulates GPX4 expression and oxidative stress

Abstract Prostate cancer (PCa) is a leading cause of mortality, primarily due to its ability to metastasize to the bone. The High Mobility Group AT-Hook 2 (HMGA2) plays a crucial role in regulating gene expression and has been implicated in tumorigenesis and the metastatic process. Our recent study revealed that overexpression of the wild-type/full-length HMGA2 isoform in PCa cells promotes cancer progression by triggering epithelial mesenchymal transition (EMT), whereas truncated HMGA2 isoform promotes progression through oxidative stress signaling. We hypothesize that HMGA2 regulates GPX4 expression and oxidative stress in PCa. We studied the expression of HMGA2 and GPX4 in various PCa cell lines including enzalutamide resistant cell line (C4-2B MDVR), LNCaP cells overexpressing HMGA2 isoforms (wild type and truncated HMGA2). Our analysis of HMGA2 and GPX4 expression in diverse PCa cell lines, shows an inverse relationship between HMGA2 and GPX4 levels. Elevated HMGA2 expression coincides with reduced GPX4 expression, leading to heightened oxidative stress and susceptibility to ferroptosis. Moreover, treatment of enzalutamide resistant cell line C4-2B MDVR with ferroptosis inducer RSL3, further suppresses GPX4 expression, resulting in decreased cell proliferation. Our results unveils the intricate relationship between HMGA2, GPX4 regulation and oxidative stress in the context of prostate cancer progression. Exploiting this oxidative stress pathway offers a promising therapeutic approach for cancer treatment, especially for enzalutamide-resistant cancer cells. Acknowledgements: These studies were supported by NIH/NIGMS/RISE SR25GM060414 and NIH/NIMHD 2U54MD007590; 5U54MD013376. Citation Format: Precious Elechi Dike, Taaliah Campbell, Mojisoluwa Awolowo, Valerie Odero-Marah. HMGA2 regulates GPX4 expression and oxidative stress [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 1562.

Abstract 2984: Prostate cancer associated glycosylated RNAs: Who are you and where are you hiding

Abstract Glycosylated RNA (glycoRNA) is an emerging field. Carbohydrate modifications are vital for biomolecule (proteins and lipids) stability, transport, and localization. Glycosylation influences cell functions like differentiation, apoptosis, and immune response, potentially impacting human disease. The Bertozzi lab initially discovered that RNAs can carry sugar modifications when they metabolically labeled mammalian cultured cells using bioorthogonal chemistry methods normally employed for glycosylated protein and lipid enrichment. Our lab wanted to investigate the translational potential of glycoRNAs and determine if these modifications could be developed as novel clinical targets for aggressive prostate cancer. (PCa). As advanced forms of PCa often lead to poor prognoses, it is imperative that better screening biomarkers and therapeutic treatment options are developed to increase patient survivorship. We predicted that glycoRNA expression would correlate with malignancy, metastatic status, and hormone sensitivity in prostate cells. Our lab used the sialic acid metabolic precursor Ac4ManNAz and click chemistry to label a panel of human prostate cancer cell lines representing the spectrum of prostate disease followed by rigorous RNA isolation procedures and northern blot analysis. We found that human prostate cell lines with no (RWPE-1) or low malignancy (LNCaP) expressed higher levels of glycoRNA belonging to the small <200 nt (but not large) noncoding RNA class compared to aggressive, metastatic PCa cell lines. Our glycosidase studies and lectin northern blot analysis indicated that RNA carries both N-linked and O-linked modifications. Based on these findings, we hypothesized that glycosylated RNA plays an important role in maintaining prostate homeostasis and in cancer protection. To better profile these glycoRNAs, we aimed to: 1) Test a wider range of metabolic labeling regents to characterize the glycoRNA populations using a panel of human prostate cell lines; 2) Perform cellular fractionation studies to determine localization of glycoRNA in prostate cells; and 3) Explore glycoRNAs in a genetic animal model. These studies focused on LNCaP PCa cell lines, which express high levels of glycoRNA. We found that small glycoRNA expression was noted when LNCaP cells were metabolically labeled with Ac4GalNAz (predominantly O-linked) and Ac4ManNAz (predominantly N-linked), verifying glycoRNA heterogeneity. Cellular fractionation studies indicated glycoRNA localization was enriched in the membrane fraction of LNCaP cells using these metabolic labels. Furthermore, we verified that C. elegans grown on Ac4GalNAz plates expressed small glycoRNA, indicating biological conservation. We are now characterizing these glycoRNAs using RNA sequencing and LC-MS/MS glycomics. Our findings will provide novel insights into cancer-associated glycoRNA, leading to improved clinical tools for PCa. Citation Format: Samantha McGuire, Esther Jones, Spencer Moen, Aurora Esquela-Kerscher. Prostate cancer associated glycosylated RNAs: Who are you and where are you hiding [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 2984.

Abstract 7228: In-vitro efficacy of Dordaviprone/GSK126 combination therapy on castration resistant and neuroendocrine prostate cancer

Abstract Neuroendocrine prostate cancer (NEPC) is an aggressive histologic subtype associated with poor prognosis that commonly arises in later stages as a mechanism of treatment resistance. Activation of oncogenic drivers, in combination with epigenetic changes (such as EZH2 overexpression and DNA methylation) further promotes tumor proliferation and expression of downstream neuroendocrine lineage pathways (in part controlled by transcription factors, including SOX2, ASCL1, and BRN2). Importantly, EZH2 inhibitors (EZH2i) can restore AR expression in CRPC (Ku et al., 2017). Imipridones, including Dordaviprone (ONC201), show promise in treating neuroendocrine tumors by interacting with DRD2 and CLpP (Anderson et al., 2022). These results warrant investigation into the potential for synergism in imipridone/EZH2i combination therapies. In the PCa cell lines LNCap, PC3, 22Rv1, and DU145 the combination of ONC201 and EZH2i GSK126 was assessed. Cell viability data after treatment with ONC201 and GSK126 reveals several dose ranges with potential synergistic activity after 72h. Preliminary western blots after 72 hours of GSK126 treatment indicate modulation of proteins relevant to the mechanism of action of imipridones, specifically DR5 and CLpP, in LNCap, PC3, and 22Rv1. Notably, the decrease in DR5 expression warrants investigation into the effects of EZH2i on TRAIL sensitivity and whether imipridones may rescue DR5 expression to maintain TRAIL sensitivity. Subsequent experiments will investigate dosing and time point-based effects on viability and protein expression, in addition to assessing the synergy of other imipridones and EZH2i’s. Further, while the cell lines PC3, 22Rv1, and DU145 are castration-resistant, the neuroendocrine prostate cell line NCI-H660 will be used as a positive control as it expresses higher neuroendocrine features, including DRD2. Additionally, the modulation in DR5 expression warrants inquiry into the effects of combination therapy on tumor-immune cell interactions. Further, we will manipulate the expression of neuroendocrine transcription factors to assess changes in therapy sensitivity. Citation Format: Connor Purcell, Praveen Srinivasan, Maximilian Pinho-Schwermann, William MacDonald, Elizabeth C. Ding, Vida Tajiknia, Wafik El-Deiry. In-vitro efficacy of Dordaviprone/GSK126 combination therapy on castration resistant and neuroendocrine prostate cancer [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 7228.

Abstract 462: Developing the miR-888 cluster as a therapeutic target for prostate cancer

Abstract Prostate Cancer (PCa) is a serious health crisis in the United States. 20% of men diagnosed with PCa will progress to fast-growing, advanced disease. There are no curative treatment options for PCa that has spread to distant sites and the 5-year survival rate for metastatic disease remains 30%. Recognizing the need for better PCa therapeutics, we are developing novel anti-microRNA delivery reagents targeted against the noncoding RNA miR-888 cluster to block prostate tumor progression. Our lab identified these oncomiRs in a biomarker discovery screen as elevated in human metastatic PCa cell lines and prostatic fluids from patients with high-grade PCa. We noted that over-expression of miR-888 cluster members (miR-888, miR-891a) promoted prostate cell growth and induced invasiveness in vitro. miR-888 and miR-891a also accelerated xenograft tumor growth in mice. Treatment of aggressive PCa cells in culture with synthetic antisense inhibitors against individual cluster members reversed these growth and invasion phenotypes, highlighting their clinical potential. We are testing pH Low Insertion Peptide (pHLIP)-Peptide Nucleic Acid (PNA)-based antimiR conjugates against miR-888 and miR-891a. The delivery vehicle pHLIP is a 36-amino acid peptide that at low pH (< pH 6.5) adopts an alpha-helical conformational change and facilitates the insertion of its C-terminus across lipid bilayers to transport conjugated anti-miRNA cargo into cells. When administered systemically, pHLIP effectively targets solid tumors with acidic microenvironments. We found that these reagents are readily internalized by human PCa cells cultured at pH 6.0 and in prostate xenograft tumors when delivered systemically in mice. Treatment significantly repressed miR-888 and miR-891a and acted to slow prostate cell growth in vitro. We are currently moving these studies into mouse prostate models. Furthermore, we are investigating the downstream signaling pathways for the miR-888 cluster. Our work indicates that the miR-888 cluster network coordinates the repression of the Tissue Inhibitors of Metalloproteinase (TIMP) and SMAD4 anti-metastatic pathways to drive extracellular matrix degradation and prostate cell invasion, and as a consequence, induces matrix metalloproteinase (MMP) activity. Expression profiling arrays and luciferase reporter assays indicated that multiple members of the miR-888 cluster co-suppress TIMPs in the prostate and similarly elevate multiple MMPs as well as cadherins, fibronectin and heparinase, and co-modulated several immune response genes. We are currently studying the consequence of various CRISPR-mediated miR-888 cluster deletions to understand how this non-coding RNA cluster functionally overlaps to promote aggressive PCa. This work will establish new clinical tools for aggressive PCa and optimize patient treatment management. Citation Format: Katherine Routon, Trevor Fachko, Vishal Kasina, Raman Bahal, Aurora Esquela Kerscher. Developing the miR-888 cluster as a therapeutic target for prostate cancer [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 462.

Abstract 4697: Surface localization of enolase-1 (ENO-1) as an attractive theranostic target in docetaxel-resistant neuroendocrine-like prostate cancer cells

Abstract Prostate cancer (PCa) is American men's second most common cancer. Although taxane-based chemotherapy is the last line of defense for Metastatic Castration Resistant Prostate Cancer (mCRPC), it invariably fails due to chemoresistance. The protein-specific membrane antigen (PSMA) has been an effective target for the imaging and therapy of mCRPC. Although PSMA radioligand therapy (PSMA-RLT) is a theranostics option for men with advanced PCa, about 30% have a limited response due to neuroendocrine-like PCa (NEPC), which lacks PSMA expression. Enolase (ENO) is a promising theranostic alternative due to its cell surface localization in many human tumors. We observed that chemosensitive PCa cell lines expressing NEPC markers express both ENO-1 and ENO-2; however, docetaxel-resistant NEPC-like cells only express ENO-1 and have a metabolic vulnerability due to the loss of ENO-2. We hypothesize that ENO-1 is expressed on the surface of NEPC-like cell lines and can be targeted with small molecule inhibitors (SMIs) that could potentially be used as theranostics agents. Additionally, we have observed changes in the expression and localization of ENO-1 in NEPC-like cell lines under different glucose concentrations. Our data show that under high glucose conditions, found on metabolically active metastatic tumors, ENO-1 is highly expressed on the cell surface, making it a promising candidate target for theranostics. However, low glucose conditions inhibit the activity of the c-MYC oncogene resulting in ENO-1 downregulation and upregulation of MBP1, the small splice variant of ENO1 that blocks the transcriptional activity of c-MYC. Our efforts to confirm ENO-1 surface expression on NEPC-like cell lines entailed using confocal microscopy, cell fractionation analysis followed by Western blotting, and Flow cytometric cell surface staining. We also evaluated the cytotoxicity of SMIs designed to target ENO-1 in chemoresistant NEPC-like cell lines using MTT viability assays, clonogenic assays, and Hoffman Modulation microscopy imaging. Our long-term goal is to identify an alternative treatment for patients with NEPC by establishing ENO-1 as a novel theranostics target. Citation Format: Krystal Rubi Santiago Torres, Carlos A. Casiano, Frankis Almaguel, Alfonso Duran, Kristen Whitley. Surface localization of enolase-1 (ENO-1) as an attractive theranostic target in docetaxel-resistant neuroendocrine-like 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 4697.

Abstract 408: NEK1 phosphorylation modulates ERCC6 in transcription coupled nucleotide excision repair with implications for prostate cancer

Abstract NER operates through two distinct pathways: global genome repair (GGR) and transcription-coupled repair (TC-NER). TC-NER, as its name suggests, is specifically dedicated to rectifying lesions that obstruct the progression of RNA polymerase during active transcription. This process is imperative for the maintenance of cellular homeostasis, as lesions encountered by the transcription machinery can lead to stalling, erroneous transcription, and ultimately, deleterious cellular outcomes. At the heart of the TC-NER pathway lies ERCC6, a helicase orchestrating the repair of DNA lesions within transcribed regions of the genome. ERCC6 (AKA CS-B) plays a pivotal role in detecting and coordinating the repair of transcription-blocking lesions and has been implicated in a plethora of cellular processes underscoring its multifaceted nature and its broader impact on genome stability and cellular health, as exemplified by the severity of syndromes in individuals with loss-of-function mutations. In the US, compared to Caucasians (CC), AA are at higher risk for developing PCa and have more aggressive disease that is refractory to treatment, to some extent explained by genetic differences in some cases attributed to alterations of their “Repairome”. GWAS revealed that, unlike CC, 89% of AA-PCa have at least one mutation in NER pathway genes. A defect in ERCC6 activity, either through reduced expression or mutation (e.g., M1097V found frequently in AA) may result in impaired TC-NER. This may be compounded by aging or obesity-related oxidative stress, resulting in progressive accumulation of damaged bases (e.g., 8-OG) and consequent (cancer-propensity) mutations, the correction of which involves BER or NER. This was investigated in part with PCa cell lines engineered via CRISPR-SDM to carry that particular genomic mutation, by studying their sensitivity to UV and the efficiency of removal of CPDs in vivo. In addition, we have begun investigation of its function in the variants (engineered and naturally found in PCa. Lines) in vitro, after IP from cells, by studying its intrinsic ATPase activity. We have also identified the kinase NEK1 as an important novel interactor and regulator of ERCC6. We previously identified NEK1 as being an early regulator of the adaptive response of PCa cells to ADT. Citation Format: Oluwatobi M. Ogundepo, Arrigo De Benedetti. NEK1 phosphorylation modulates ERCC6 in transcription coupled nucleotide excision repair with implications for prostate cancer [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 408.

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 5897: Understanding and targeting fatty acid CoA ligase ACSL4 in human prostate cancer

Abstract Prostate cancer (PCa) is the most common non-cutaneous malignancy among men. Although localized prostate cancer is curable, recurrence of metastatic castration-resistant prostate cancer (mCRPC) is almost inevitable and is the major cause of death in human PCa. Recent findings from our lab and others demonstrate that RB1 loss drives lineage plasticity, metastasis, and lethality of prostate tumors initiated by PTEN loss. A downstream target upregulated by RB1 loss is acyl CoA synthetase long chain family member 4 (ACSL4), a fatty acid ligase with an essential role in utilization of long chain fatty acids. ACSL4 has been reported to be upregulated in cancers of various histological origins, including prostate cancer, and its high expression is correlated with aggressiveness of cancer. We hypothesize that ACSL4 is a critical downstream effector of RB1 loss-driven prostate tumorigenesis and pharmacological inhibition of ACSL4 could represent a novel therapeutic approach to the treatment of lethal RB1 deficient or ACSL4 overexpressing prostate cancer. Here we aim to develop novel ACSL4 inhibitors for preclinical studies. Through a structure based virtual screening that targeted ATP binding domains of ACSL4, we successfully identified 15 potential ACSL4 inhibitors. To validate the result, we performed an in vitro screening using various parental and isogenic human PCa cell lines, and found that 4 out of 15 compounds effectively inhibited PCa cell proliferation in a dose-response manner and their inhibitory effects positively correlated with cellular levels of ACSL4. Next, we will perform isotope-labeling enzyme activity assays to determine the specificity of the 4 candidate drugs, and PDPK analyses followed by characterizing their in vivo efficacies in preclinical studies, with a final goal to develop a well-validated ACSL4 inhibitor. Successful completion of this work will provide great insights into contributions of ACSL4 to prostate tumorigenesis as well as preclinical data of ACSL4 inhibitors to treat lethal prostate cancer. Citation Format: Jinjin Wu, Mu-En Wang, Ming Chen, Pyeong Hwa Jeong, Jiyong Hong, Lixin Wan. Understanding and targeting fatty acid CoA ligase ACSL4 in human prostate cancer [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 5897.

O140: How clinically relevant are prostate cancer cell lines? A comprehensive multiomics analysis.

Abstract Introduction Cell lines remain a heavily used resource in cancer research despite their questionable clinical relevance, mainly due to their feasibility and affordability. A range of in silico, in vivo and ex vivo approaches are gaining popularity to potentially replace cell lines, however, we cannot ignore the plethora of historical data from cell lines, nor write off their future use. Therefore, we question if and how cell lines hold clinical relevance. Methods The clinical characteristics of 45 PCa cell lines were compared against worldwide data and the biological features of seven cell lines were compared to over 10,000 well-characterised cases from 23 studies in eight countries. Clinical comparisons included age, race, Gleason grade, cancer type and multiomics variables included mutations, copy number alterations, structural variants, microsatellite instability, mRNA and protein expression, and tumour mutational burden. Using this, cell-line-like patients were identified and characterised. Results The most used cell lines were derived from metastases over 40 years ago and accurately represented very few patients. The most common alterations in clinical datasets were not necessarily altered in cell lines and 24% of key PCa gene alterations were not altered in any cell line. From the seven cell lines analysed, the greatest number of patients were found to be biologically similar to VCaP. Conclusion Cell lines are valuable in cancer research, but they must hold biological and clinical relevance. PCa cell lines should either be applicable to typical PCa patients or representative of specific cancer subtypes to increase the relevance of translational research.