Androgen-independent Cells Research Articles

NFYA-mediated promotion of castration-resistant prostate cancer progression through EGR4 regulation

This research investigates the intricate involvement of nuclear Transcription Factor Y Subunit Alpha (NFYA) in the advancement of castration-resistant prostate cancer (CRPC) and its consequential impact on early Growth Response 4 (EGR4) expression. NFYA demonstrates a significant elevation in CRPC tissues and cell lines, displaying robust upregulation in metastatic prostate cancer (mPCa) samples, closely associated with the Gleason score. Immunohistochemistry validates heightened nuclear staining of NFYA in CRPC patients, highlighting its crucial role in the progression of advanced prostate cancer. Silencing NFYA through siRNA in androgen-independent cell lines markedly impedes cell growth and migration, emphasizing NFYA’s pivotal role in promoting CRPC behavior. RNA-seq analysis identifies EGR4 as a downstream target of NFYA, with both genes consistently upregulated in CRPC. Validating this finding, heightened expression of EGR4 is observed in CRPC samples. In vivo studies utilizing a mouse model demonstrate that NFYA silencing substantially inhibits LNCaP-AI/22RV1shNFYA xenograft tumor growth, accompanied by reduced expression of EGR4 and Ki67. This comprehensive study reveals the multifaceted role of NFYA in CRPC progression, elucidates its downstream impact on EGR4, and underscores the therapeutic potential of targeting NFYA to inhibit CRPC growth in vivo. These findings contribute valuable insights into potential therapeutic strategies for managing CRPC.

A joint-threshold Filippov model describing the effect of intermittent androgen-deprivation therapy in controlling prostate cancer

Intermittent androgen-deprivation therapy (IADT) can be beneficial to delay the occurrence of treatment resistance and cancer relapse compared to the standard continuous therapy. To study the effect of IADT in controlling prostate cancer, we developed a Filippov prostate cancer model with a joint threshold function: therapy is implemented once the total population of androgen-dependent cells (AC-Ds) and androgen-independent cells (AC-Is) is greater than the threshold value ET, and it is suspended once the population is less than ET. As the parameters vary, our model undergoes a series of sliding bifurcations, including boundary node, focus, saddle, saddle-node and tangency bifurcations. We also obtained the coexistence of one, two or three real equilibria and the bistability of two equilibria. Our results demonstrate that the population of AC-Is can be contained at a predetermined level if the initial population of AC-Is is less than this level, and we choose a suitable threshold value.

From Androgen Dependence to Independence in Prostate Cancer: Unraveling Therapeutic Potential and Proteomic Landscape of Hydroxychloroquine as an Autophagy Inhibitor.

Prostate cancer is a major planetary health challenge wherein new ways of thinking drug discovery and therapeutics innovation are much needed. Numerous studies have shown that autophagy inhibition holds a significant role as an adjunctive intervention in prostate cancer. Hydroxychloroquine (HCQ) has gained considerable attention due to its established role as an autophagy inhibitor across diverse cancer types, but its proteomics landscape and systems biology in prostate cancer are currently lacking in the literature. This study reports the proteomic responses to HCQ in prostate cancer cells, namely, androgen-dependent LNCaP and androgen-independent PC3 cells. Differentially expressed proteins and proteome in HCQ-treated cells were determined by label-free quantification with nano-high-performance liquid chromatography and tandem mass spectrometry (nHPLC-MS/MS), and harnessing bioinformatics tools. In PC3 cells, there was a marked shift toward metabolic reprogramming, highlighted by an upregulation of mitochondrial proteins in oxidative phosphorylation and tricarboxylic acid cycle, suggesting an adaptive mechanism to maintain energy production under therapeutic stress. In contrast, LNCaP cells prioritized proteostasis and cell cycle regulation, indicating a more conservative adaptation strategy. To the best of our knowledge, this study is the first to demonstrate the differential responses of prostate cancer cells to autophagy inhibition by HCQ, suggesting that a combination therapy approach, targeting distinct pathways in androgen-independent and androgen-dependent cells, could represent a promising treatment strategy. Moreover, the varied proteomic responses observed between these cell lines underscore the importance of personalized medicine in cancer therapy. Future translational and clinical research on HCQ and prostate cancer are called for.

Identification of ferroptosis related genes and pathways in prostate cancer cells under erastin exposure

BackgroundFew studies are focusing on the mechanism of erastin acts on prostate cancer (PCa) cells, and essential ferroptosis-related genes (FRGs) that can be PCa therapeutic targets are rarely known.MethodsIn this study, in vitro assays were performed and RNA-sequencing was used to measure the expression of differentially expressed genes (DEGs) in erastin-induced PCa cells. A series of bioinformatic analyses were applied to analyze the pathways and DEGs.ResultsErastin inhibited the expression of SLC7A11 and cell survivability in LNCaP and PC3 cells. After treatment with erastin, the concentrations of malondialdehyde (MDA) and Fe2+ significantly increased, whereas the glutathione (GSH) and the oxidized glutathione (GSSG) significantly decreased in both cells. A total of 295 overlapping DEGs were identified under erastin exposure and significantly enriched in several pathways, including DNA replication and cell cycle. The percentage of LNCaP and PC3 cells in G1 phase was markedly increased in response to erastin treatment. For four hub FRGs, TMEFF2 was higher in PCa tissue and the expression levels of NRXN3, CLU, and UNC5B were lower in PCa tissue. The expression levels of SLC7A11 and cell survivability were inhibited after the knockdown of TMEFF2 in androgen-dependent cell lines (LNCaP and VCaP) but not in androgen-independent cell lines (PC3 and C4-2). The concentration of Fe2+ only significantly increased in TMEFF2 downregulated LNCaP and VCaP cells.ConclusionTMEFF2 might be likely to develop into a potential ferroptosis target in PCa and this study extends our understanding of the molecular mechanism involved in erastin-affected PCa cells.

Abstract 4656: Novel mitochondria-based targeting overcomes resistance in prostate cancer

Abstract Background: Prostate cancer (PC) is a major contributor to cancer-related mortality in men, with metastatic castration-resistant PC (mCRPC) presenting a significant obstacle due to its resistance to standard treatments. Current therapies, including nonsteroidal antiandrogens and chemotherapy drugs, provide limited effectiveness and are often accompanied by severe side effects. Recently, statins have gained attention as antitumor agents, demonstrating chemopreventive effects on a range of human cancers while maintaining a well-established safety profile. However, the use of statins as standalone treatment is limited by insufficient cancer cell targeting. Methods: We synthesized a DZ-simvastatin (DZ-SIM) conjugate that combines a near-infrared heptamethine carbocyanine dye (DZ) with simvastatin for selective tumor cell targeting. Cancer cell survival was measured by crystal violet and MTT assay. Co-localization of DZ-SIM with mitochondria and lysosome in cells was detected under confocal microscope using Mitotracker and Lysotracker. Cellular and mitochondrial cholesterol levels were detected by LC-MS. Male nude mice were inoculated subcutaneously with 22Rv1-Luc cells as a prostate cancer xenograft mouse model. We used Swiss-PDB and Rosetta algorithms to model the structure of the OATP1B3 channel. Oxygen consumption rate and extracellular acidification rate were measured by Seahorse assay. After treatment with DZ-SIM, differentially expressed genes profiling of prostate cancer cells was performed using RNAseq. Results: Our research demonstrates the conjugate's ability to effectively kill androgen-independent and metastatic PC cells without harming normal cells. Furthermore, DZ-SIM has been shown to kill multiple human PC cell lines, regardless of androgen receptor status or therapeutic resistance. DZ-SIM has been shown to inhibit growth in human prostate cancer cell line xenograft models. NIR fluorescence imaging showed specific localization of DZ-SIM to cancer, but not to normal cells and tissues. It could localize into cancer cells by binding the transmembrane transporter OATP to primarily target subcellular organelle mitochondria, decreasing the OCR and ECAR of cancer cells. DZ-SIM can bind to multiple cytosolic and mitochondrial proteins as detected by NIRF imaging. Cholesterol levels also decrease in whole cells and mitochondria. Ingenuity Pathway Analysis (IPA) of RNAseq showed that the four signaling pathways in the DZ-SIM treatment group are significantly enriched in genes related to cholesterol synthesis. Conclusion: DZ-SIM specifically targets PC cells and their mitochondria, resulting in loss of mitochondrial function and consequent cell death. With a unique subcellular targeting strategy, the conjugate holds the potential to outperform existing chemotherapeutic drugs. Citation Format: Yan Ou, Adrian Lim, Ning Zhai, Mouad Edderkaoui, Stephen Pandol, Ruoxiang Wang, Yi Zhang. Novel mitochondria-based targeting overcomes resistance in 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 4656.

Aloe-emodin exhibits growth-suppressive effects on androgen-independent human prostate cancer DU145 cells via inhibiting the Wnt/β-catenin signaling pathway: an in vitro and in silico study.

At the molecular level, several developmental signaling pathways, such as Wnt/β-catenin, have been associated with the initiation and subsequent progression of prostate carcinomas. The present report elucidated the anti-cancerous attributes of an anthraquinone, aloe-emodin (AE), against androgen-independent human prostate cancer DU145 cells. The cytotoxicity profiling of AE showed that it exerted significant cytotoxic effects and increased lactose dehydrogenase levels in DU145 cells (p < 0.01 and p < 0.001). AE also induced considerable reactive oxygen species (ROS)-mediated oxidative stress, which escalated at higher AE concentrations of 20 and 25μM. AE also efficiently instigated nuclear fragmentation and condensation concomitantly, followed by the activation of caspase-3 and -9 within DU145 cells. AE further reduced the viability of mitochondria with increased cytosolic cytochrome-c levels (p < 0.01 and p < 0.001) in DU145 cells. Importantly, AE exposure was also correlated with reduced Wnt2 and β-catenin mRNA levels along with their target genes, including cyclin D1 and c-myc. Furthermore, the molecular mechanism of AE was evaluated by performing molecular docking studies with Wnt2 and β-catenin. Evidently, AE exhibited good binding energy scores toward Wnt2 and β-catenin comparable with their respective standards, CCT036477 (Wnt2 inhibitor) and FH535 (β-catenin inhibitor). Thus, it may be considered that AE was competent in exerting anti-growth effects against DU145 androgen-independent prostate cancer cells plausibly by modulating the expression of Wnt/β-catenin signaling.

Oridonin attenuated human PC-3 cell activity by modulating the Wnt/β-catenin signaling.

Prostate cancer (PC) prevention is effectively achieved through its inhibition. Oridonin (ORD), an active diterpenoid isolated from Rabdosia rubescens, has been shown to have an inhibitory effect on PC cells, although its impact on PC is unknown. The present work investigated the actions and probable mechanisms of ORD on cellular proliferation, apoptosis, PC, and the wingless-type MMTV integration site family member 2 (Wnt)/β-catenin signaling pathway using the androgen-independent PC-3 cell line. In this study, cell viability was analyzed with MTT assay method, apoptotic morphology determined using DAPI dye method, while protein (CD1333, OCT-4, Nanog, SOX-2 & Aldh1A1) and mRNA expressions were analyzed with western blotting and real time polymerase chain reaction (PCR). We demonstrated a concentration-dependent ORD inhibition of PC-3 cell proliferation and inhibition of induction apoptosis. Furthermore, ORD decreased PC-3 Wnt-2, phosphorylated glycogen synthase kinase-3 (p-GSK3), and β-catenin protein levels and downregulated cyclin-D1 and c-myc messenger ribonucleic acid (mRNA). Oridonin inhibited proliferation and induced apoptosis in PC-3 cells, with the findings suggesting that it acted via the Wnt/β-catenin pathway to exert its effects. This study demonstrates that ORD may impact PC.

THE EFFECT OF PARGILINE, SPERMINE AND THEIR COMBINATIONS ON ANDROGEN-DEPENDENT AND ANDROGEN-INDEPENDENT HUMAN PROSTATE CANCER CELLS in vitro

Summary. A series of studies on enhancing the cytotoxic effect of spermine on human prostate cells by affecting the enzymes of its metabolism has been continued. Aim: to investigate effects of pargyline, spermine and their combinations the survival, ζ-potential and surface charge and cytomorphological properties of human prostate cancer cells in culture. Object and methods: studies were conducted on cell cultures: differentiated androgen-dependent LNCaP cell line and low-differentiated androgen-independent DU-145 cell line. Cell survival was determined in the trypan blue assay. The effect of the investigated compounds, both individually and in combination, on the viability and proliferative activity of cells was assessed by the colorimetric method – by staining living cells with a solution of crystal violet in methanol. Biophysical parameters (ζ-potential and surface electric charge density) were determined according to the method cellular microelectrophoresis. Cytomorphological characteristics were studied on preparations of cells grown on coverslips, fixed and stained with hematoxylin and eosin (magnification 1000×). Results: for LNCaP cells, the IC50 of pargyline was 2.2 mM, and the IC50 of spermine was 1.5 mM. For DU-145 cells, the IC50 of pargyline was 2.35 mM, the IC50 of spermine was 5.0 mM. According to biophysical indicators, spermine caused an inversion of the sign of the electric charge in cells of the LNCaP line. Pargyline did not exert such an effect, the charge remained negative, demonstrating an inverse dependence on its concentration. The combination of pargyline and spermine increased the cytotoxic effect of spermine on LNCaP cells, but did not affect the value of their ζ-potential and surface charge density, the positive sign of which, caused by the effect of spermine, was preserved. At the same time, pargyline completely eliminated spermine-induced inversion of the sign of the total surface charge of DU-145 cells, returning it to the normal negative values. Conclusions: it is shown that the differentiated androgen-dependent cells of the LNCaP line with the combined use of pargyline and spermine demonstrated an enhancement of the cytotoxic effect of spermine. At the same time, low-differentiated cells of the DU-145 line, which do not have androgen receptors, were more resistant to the effects of both pargyline and pargyline in combination with spermine. Pargyline also reversed spermine-induced inversion of the sign of the total surface charge of DU-145 cells, returning it to normal negative values. Cytomorphological changes that occurred under the influence of both pargyline alone and in its combination with spermine demonstrate mainly the apoptotic pathway of cell death in the androgen-independent DU-145 line, while in the androgen-dependent LNCaP line, a smaller proportion of cells were in a state of apoptosis.

Simvastatin Enhances the Radiosensitivity of Androgen-independent Prostate Cancer Cells via Inhibition of RAD51 Expression.

Statins exert antitumor effects via various mechanisms. Additionally, the recurrence rate of prostate cancer after radiation therapy is lower in patients taking statins. This study investigated the efficacy of combination therapy with statins and irradiation in androgen-independent prostate cancer cells. PC-3 and LNCaP human prostate cancer cell lines were used in this study. We developed androgen-independent LNCaP cells (LNCaP-LA) by gradually replacing fetal bovine serum (FBS) with charcoal-stripped FBS. Microarray analysis was performed, followed by Ingenuity Pathway Analysis. Cell viability was determined using the MTS assay. Simvastatin alters gene expressions in PC-3 cells. Microarray data showed that the number of differentially expressed genes was the highest in the pathway of "Role of BRCA1 in DNA Damage Response". In the validation, the expression of RAD51, listed in "Role of BRCA1 in DNA Damage Response", decreased significantly by simvastatin in PC-3 cells. Reduction in RAD51 expression following siRNA transfection increased the cytocidal effects of X-ray therapy in PC-3 and LNCaP-LA cells. The combination of simvastatin and irradiation further inhibited cell proliferation compared with monotherapy with either therapy in PC-3 or LNCaP-LA cells. In addition, compared with X-ray monotherapy, the combination of simvastatin and irradiation further enhanced the expression of γH2AX, which is reported to be one of the accurate markers of DNA damage in PC-3 cells. Simvastatin decreased the expression of RAD51 in androgen-independent prostate cancer cells. The combination of irradiation and drugs that reduce RAD51 expression can potentially affect androgen-independent prostate cancer growth.

Integrative analysis of transcriptomic and metabolomic profiles reveals enhanced arginine metabolism in androgen-independent prostate cancer cells

BackgroundProstate cancer is a common solid tumor that affects a significant number of men worldwide. Conventional androgen deprivation therapy (ADT) increases the risk of developing castration-resistant prostate cancer (CRPC). Effective clinical management of patients with CRPC is challenging due to the limited understanding.MethodsIn this study, transcriptomic and metabolomic profiles of androgen-dependent prostate cancer cell line LNCaP and the androgen-independent cells developed from LNCaP cells (LNCaP-ADR) were investigated using RNA-sequencing and LC-MS/MS, respectively. The differentially expressed genes and metabolites were analyzed, and integrative analysis of transcriptomic and metabolomic data was further conducted to obtain a comprehensive understanding of the metabolic characteristics in LNCaP-ADR cells. Quantitative real-time PCR (QPCR) was employed to ascertain the mRNA expression levels of the selected differentially expressed genes.ResultsThe arginine and proline metabolism pathway was identified as a commonly altered pathway at both the transcriptional and metabolic levels. In the LNCaP-ADR cells, significant upregulation was observed for metabolites including 5-Aminopentanoic acid, L-Arginine, L-Glutamic acid, N-Acetyl-L-alanine, and Pyrrole-2-carboxylic acid at the metabolic level. At the transcriptional level, MAOA, ALDH3A2, ALDH2, ARG1, CKMT2, and CNDP1 were found to be significantly upregulated in the LNCaP-ADR cells. Gene set enrichment analysis (GSEA) identified various enriched gene sets in the LNCaP-ADR cells, encompassing inflammatory response, 9plus2 motile cilium, motile cilium, ciliary plasm, cilium or flagellum-dependent cell motility, cilium movement, cilium, response to endoplasmic reticulum stress, PTEN DN.V1 DN, SRC UP.V1 UP, IL15 UP.V1 DN, RB DN.V1 DN, AKT UP MTOR DN.V1 UP, VEGF A UP.V1 UP, and KRAS.LUNG.BREAST UP.V1 UP.ConclusionsThese findings highlight the substantial association between the arginine and proline metabolism pathway and CRPC, emphasizing the need to prioritize strategies that target dysregulated metabolites and differentially expressed genes as essential interventions in the clinical management of CRPC.

Targeting Metabolic Vulnerabilities to Overcome Prostate Cancer Resistance: Dual Therapy with Apalutamide and Complex I Inhibition

Prostate cancer (PCa) often becomes drug-treatment-resistant, posing a significant challenge to effective management. Although initial treatment with androgen deprivation therapy can control advanced PCa, subsequent resistance mechanisms allow tumor cells to continue growing, necessitating alternative approaches. This study delves into the specific metabolic dependencies of different PCa subtypes and explores the potential synergistic effects of combining androgen receptor (AR) inhibition (ARN with mitochondrial complex I inhibition (IACS)). We examined the metabolic behaviors of normal prostate epithelial cells (PNT1A), androgen-sensitive cells (LNCaP and C4-2), and androgen-independent cells (PC-3) when treated with ARN, IACS, or a combination. The results uncovered distinct mitochondrial activities across PCa subtypes, with androgen-dependent cells exhibiting heightened oxidative phosphorylation (OXPHOS). The combination of ARN and IACS significantly curbed cell proliferation in multiple PCa cell lines. Cellular bioenergetics analysis revealed that IACS reduced OXPHOS, while ARN hindered glycolysis in certain PCa cells. Additionally, galactose supplementation disrupted compensatory glycolytic mechanisms induced by metabolic reprogramming. Notably, glucose-deprived conditions heightened the sensitivity of PCa cells to mitochondrial inhibition, especially in the resistant PC-3 cells. Overall, this study illuminates the intricate interplay between AR signaling, metabolic adaptations, and treatment resistance in PCa. The findings offer valuable insights into subtype-specific metabolic profiles and propose a promising strategy to target PCa cells by exploiting their metabolic vulnerabilities.

Cell Plasticity in a Mouse Model of Benign Prostate Hyperplasia Drives Amplification of Androgen-Independent Epithelial Cell Populations Sensitive to Antioxidant Therapy

Benign prostate hyperplasia (BPH) is caused by the nonmalignant enlargement of the transition zone of the prostate gland, leading to lower urinary tract symptoms. Although current medical treatments are unsatisfactory in many patients, the limited understanding of the mechanisms driving disease progression prevents the development of alternative therapeutic strategies. The probasin-prolactin (Pb-PRL) transgenic mouse recapitulates many histopathological features of human BPH. Herein, these alterations parallel urodynamic disturbance reminiscent of lower urinary tract symptoms. Single-cell RNA-sequencing analysis of Pb-PRL mouse prostates revealed that their epithelium mainly includes low-androgen signaling cell populations analogous to Club/Hillock cells enriched in the aged human prostate. These intermediate cells are predicted to result from the reprogramming of androgen-dependent luminal cells. Pb-PRL mouse prostates exhibited increased vulnerability to oxidative stress due to reduction of antioxidant enzyme expression. One-month treatment of Pb-PRL mice with anethole trithione (ATT), a specific inhibitor of mitochondrial ROS production, reduced prostate weight and voiding frequency. In human BPH-1 epithelial cells, ATT decreased mitochondrial metabolism, cell proliferation, and stemness features. ATT prevented the growth of organoids generated by sorted Pb-PRL basal and LSCmed cells, the two major BPH-associated, androgen-independent epithelial cell compartments. Taken together, these results support cell plasticity as a driver of BPH progression and therapeutic resistance to androgen signaling inhibition, and identify antioxidant therapy as a promising treatment of BPH.

LB10 - Cell plasticity in a mouse model of benign prostate hyperplasia drives amplification of androgen-independent epithelial cell populations sensitive to antioxidant therapy

LB10 - Cell plasticity in a mouse model of benign prostate hyperplasia drives amplification of androgen-independent epithelial cell populations sensitive to antioxidant therapy

In Silico Bioinformatics Analysis on the Role of Long Non-Coding RNAs as Drivers and Gatekeepers of Androgen-Independent Prostate Cancer Using LNCaP and PC-3 Cells.

Prostate cancer (PCa) is the leading cancer in men globally. The association between PCa and long non-coding RNAs (lncRNAs) has been reported. Aberrantly expressed lncRNAs have been documented in each of the cancer "hallmarks". Androgen signaling plays an important role in PCa progression. This study aimed to profile the aberrantly expressed lncRNAs in androgen-dependent (LNCaP) PCa compared to androgen-independent (PC-3) PCa cells. This was achieved by using a 384-well plate of PCa lncRNA gene panel. Differential expression of ±2 up or downregulation was determined using the CFX Maestro software v2.1. LncSEA and DIANA-miRPath were used to identify the enriched pathways. Telomerase RNA component (TERC) lncRNA was illustrated to participate in various tumourigenic classes by in silico bioinformatics analysis and was thus selected for validation using RT-qPCR. Further bioinformatics analysis revealed the involvement of differentially expressed lncRNAs in oncogenic pathways. Some lncRNAs undergo hypermethylation, others are encapsulated by exosomes, while others interact with several microRNAs (miRNAs), favouring tumourigenic pathways. Notably, TERC lncRNA was shown to interact with tumour-suppressor miRNAs hsa-miR-4429 and hsa-miR-320b. This interaction in turn activates TGF-β-signaling and ECM-receptor interaction pathways, favouring the progression of PCa. Understanding lncRNAs as competitive endogenous RNA molecules and their interactions with miRNAs may aid in the identification of novel prognostic PCa biomarkers and therapeutic targets.

Effects of IL-6 and TNF-α Cytokines on Cell Proliferation in Androgen Dependent/Independent Prostate Cancer Cell Lines

Prostate cancer is one of the most common types of cancer worldwide. Prostate cancer, caused by abnor-mal and uncontrolled growth of the cells that make up the prostate tissue, is second only to relalated deaths in men. Cytokines, which have a significant impact on the response of the immune system, play an active role in the development of prostate cancer. This study determined the effect of proinflammatory cytokines, IL-6 and TNF-a on the proliferation of prostate cancer cell lines. MTT test was used for the effect of cytokines applied at different doses and hours on cell viability. According to our results, IL-6 cytokine caused a high increase in proliferation in androgen-dependent LNCaP cells, while androgen-independent PC-3 cells showed different proliferative effects in time and dose-dependent manner. TNF-α cytokine had a negative effect on the proliferation of androgen-dependent LNCaP cells, while it increased the proliferation level of androgen-independent PC-3 cells. These results show that the effects of cell lines-on the proliferation of cells are different depending on their androgen sensitivity, which will be used in different cytokinetic studies to determine the inflammatory response to treat prostate cancer. It is espe-cially important to consider this condition during the development of prostate cancer treatment strategies.

Taraxasterol suppresses the proliferation and tumor growth of androgen-independent prostate cancer cells through the FGFR2-PI3K/AKT signaling pathway

Prostate cancer (PCa) is prevalent among older men and difficult to survive after metastasis. It is urgent to find new drugs and treatments. Several studies show that taraxasterol (TAX) has important anti-inflammatory, anti-oxidative and anti-tumor effects. However, the function and mechanisms of TAX in PCa remain unclear. Here, we found that TAX could significantly suppress the viability and growth of androgen-independent PCa cells and down-regulate the expression of c-Myc and cyclin D1 in vitro. Mechanistically, PI3K/AKT signaling pathway was weakened and the expression of FGFR2 was reduced after TAX treatment in androgen-independent PCa cells. Moreover, TAX evidently inhibited the tumor growth in nude mice and the expression of c-Myc, cyclin D1, p-AKT and FGFR2 were down-regulated in xenograft tumor. These results indicate that TAX suppresses the proliferation of androgen-independent PCa cells via inhibiting the activation of PI3K/AKT signaling pathway and the expression of FGFR2, which means TAX may be a novel anti-tumor agent for later PCa treatment.

3,5,7-trihydroxyflavone restricts proliferation of androgen-independent human prostate adenocarcinoma cells by inducing ROS-mediated apoptosis and reducestumour growth.

Flavonoids are among the largest groups of secondary metabolites. Studies suggestthat dietary intake of flavonoids reducesthe risk of cancer. 3,5,7-trihydroxyflavone (THF) belongs to the flavone class of flavonoids and potentially inhibits the growth of many cancers; however, it is unexplored in prostate cancer. This study reports the antiproliferative potential of THF in prostate cancer cell line via reactive oxygen species (ROS)-mediated cascades and examines the tumour reduction potential in swiss albino mice. The potency of THF was evaluated by employing cytotoxicity assays and wound healing assays. Cell cycle, ROS, mitochondrial membrane potential (MMP), and Annexin-V-FITC assay were performed using a flow cytometer. In vivo, anticancer potential was achieved using the mice Ehrlich Ascites Carcinoma (EAC) model. THF inhibits cell growth with IC50 of 64.30 µM (MTT), 81.22 µM (NRU) and 25.81 µM (SRB), substantiated by cell migration assay. Cell-cycle analysis revealed that THF increases the subdiploid population. Furthermore, the Annexin-V-FITC assay evoked a significant induction of late apoptosis at a higher concentration of THF. THF also disrupts MMP, caused by an increased generation of ROS. In the EAC model, THF significantly inhibits tumour growth and increases the percent survival of mice and ROS levels in EAC cells. Hence, it may be concluded that THF might execute its antiproliferative effect via inducing ROS generation and could be a promising lead for preclinical and clinical validations.

Novel α-Trifluoromethyl Chalcone Exerts Antitumor Effects Against Prostate Cancer Cells.

Despite treating advanced prostate cancer (PCa) with androgen deprivation therapy, it eventually progresses to castration-resistant PCa. Subsequently, taxanes are administered, but when PCa becomes resistant to taxanes, another treatment is needed, which has not yet been established. We previously synthesized a novel α-trifluoromethyl chalcone, YS71, and reported its antitumor effects against PCa cells. In this study, we confirmed its efficacy against androgen-sensitive, androgen-independent, and taxane-resistant PCa cells. The PCa cell lines used were LNCaP, PC-3, DU145, PC-3-TxR (paclitaxel-resistant), PC-3-TxR/CxR (paclitaxel- and cabazitaxel-resistant), DU145-TxR, and DU145-TxR/CxR. The antiproliferative effects of YS71 were evaluated using proliferation assay. The reverse transcriptase transcription-polymerase chain reaction and western blot were performed to determine the expression level of androgen receptor (AR), whereas luciferase assay was performed to determine the AR activity. Furthermore, TUNEL assay and western blot were performed to investigate the mechanism of the antiproliferative effect. YS71 exerted a dose-dependent antitumor effect, inhibited AR activity, and induced apoptosis in all PCa cells in a dose-dependent manner. Western blot showed that YS71 increased the levels of apoptosis-related proteins, cleaved caspase-3, and cleaved PARP, and decreased the levels of the antiapoptotic proteins, Bcl-xL and Bcl-2. In addition, microarray analysis revealed that YS71 decreased several cancer-related genes. YS71 exhibits antitumor activity by inducing apoptosis in PCa cells, including taxane-resistant cells. It could be a potential future therapeutic option for hormone- and chemotherapy-resistant PCa.

Chronic hypoxia favours adoption to a castration-resistant cell state in prostate cancer

Predicting and treating recurrence in intermediate-risk prostate cancer patients remains a challenge despite having identified genomic instability [1] and hypoxia [2, 3] as risk factors. This underlies challenges in assigning the functional impact of these risk factors to mechanisms promoting prostate cancer progression. Here we show chronic hypoxia (CH), as observed in prostate tumours [4], leads to the adoption of an androgen-independent state in prostate cancer cells. Specifically, CH results in prostate cancer cells adopting transcriptional and metabolic alterations typical of castration-resistant prostate cancer cells. These changes include the increased expression of transmembrane transporters for the methionine cycle and related pathways leading to increased abundance of metabolites and expression of enzymes related to glycolysis. Targeting of the Glucose Transporter 1 (GLUT1) identified a dependency on glycolysis in androgen-independent cells. Overall, we identified a therapeutically targetable weakness in chronic hypoxia and androgen-independent prostate cancer. These findings may offer additional strategies for treatment development against hypoxic prostate cancer.

Abstract 5047: PSMA-targeted actinium-225 conjugate (225Ac-pelgifatamab) potentiates the antitumor efficacy of darolutamide in androgen-dependent and -independent prostate cancer models

Abstract Patients with advanced prostate cancer have few treatment options. While androgen receptor (AR) inhibitors are the standard of care for the systemic treatment, patients often develop resistance despite an initial response. Thus, novel therapeutic approaches are required. Prostate-specific membrane antigen (PSMA; FOLH1) is highly expressed in prostate cancer with limited expression in normal tissues. Therefore, PSMA presents an attractive target for radionuclide therapy and PSMA-targeted therapies have already shown efficacy in the clinical setting. Here, we evaluated the efficacy of 225Ac-pelgifatamab, a PSMA-targeted actinium-225 conjugate, in combination with the AR inhibitor darolutamide in androgen-dependent and -independent prostate cancer models. AR inhibitors are known to upregulate PSMA expression, therefore providing a rationale for combining 225Ac-pelgifatamab with darolutamide and potentially resulting in an enhanced treatment effect. In vitro, darolutamide induced the expression of PSMA in androgen-dependent VCaP and androgen-independent 22Rv1 cells by more than 10-fold and 2-fold, respectively. The efficacy of darolutamide in combination with 225Ac-pelgifatamab was synergistic in these cells with combination indexes of 0.12 and 0.47, respectively. In the androgen-dependent, patient-derived ST1273 model, a single i.v. injection of 225Ac-pelgifatamab at 75 kBq/kg resulted in a treatment/control (T/C) ratio of 0.22 on day 30, while twice daily (BID) oral (p.o.) treatment with 100 mg/kg darolutamide showed a T/C ratio of 0.29. However, the combination of darolutamide and 225Ac-pelgifatamab resulted in enhanced antitumor efficacy with a T/C ratio of 0.008. Furthermore, 5/10 mice remained tumor-free 86 days after the 225Ac-pelgifatamab injection. In the androgen-independent cell line-derived 22Rv1 model, darolutamide (100 mg/kg, p.o., BID) monotherapy was not efficacious with a T/C of 0.84 on day 16 but a single i.v. dose of 225Ac-pelgifatamab at 150 kBq/kg resulted in a T/C ratio of 0.69. Remarkably, the combination of darolutamide and 225Ac-pelgifatamab resulted in further enhanced efficacy with a T/C ratio of 0.34. Flow cytometric analysis of isolated 22Rv1 tumors showed a 50-fold increase in PSMA expression upon darolutamide treatment compared with vehicle. Taken together, these results suggest that upregulation of PSMA expression contributes to the higher efficacy observed when darolutamide is combined with 225Ac-pelgifatamab. In conclusion, our results provide a proof of concept for investigating the combination of 225Ac-pelgifatamab with darolutamide in the clinical setting. Citation Format: Christoph A. Schatz, Bernard Haendler, Sabine Zitzmann-Kolbe, Aasmund Larsen, Hartwig Hennekes, Carsten H. Nielsen, Maria Z. Alfsen, Alan Cuthbertson, Stefanie Hammer, Arne Scholz, Urs B. Hagemann. PSMA-targeted actinium-225 conjugate (225Ac-pelgifatamab) potentiates the antitumor efficacy of darolutamide in androgen-dependent and -independent prostate cancer models. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5047.