Inhibits Prostate Cancer Growth Research Articles

Green formulation of copper nanoparticles by Pistacia khinjuk leaf aqueous extract: Introducing a novel chemotherapeutic drug for the treatment of prostate cancer

Abstract Prostate cancer is a cancer prevalent form characterized by serious clinical symptoms. The discovery of a novel supplement or medication for prostate cancer within the realm of chemotherapeutic drugs holds significant value. Our research involved the synthesis of copper nanoparticles (CuNPs) infused with Pistacia khinjuk leaf extract to explore their potential anti-prostate cancer, cytotoxic, and antioxidant properties. The green-formulated CuNPs were characterized by TEM, UV-Vis spectrophotometry, FE-SEM, FTIR. The FE-SEM and TEM findings prove the spherical structure with a size of 10–70 nm. The DPPH assay was carried out to examine the effectiveness of antioxidants. CuNPs exhibited the ability to inhibit 50% of DPPH at 215 µg/mL. To assess the anti-prostate cancer properties of CuNPs, an MTT assay was performed on NCI-H660, DU 145, LNCaP clone FGC, and LNCaP clone FGC-Luc2 cells. CuNPs exhibited remarkable efficacy in inhibiting prostate cancer growth, while demonstrating negligible toxicity towards normal cells. The LNCaP clone FGC cell line displayed the most potent anti-prostate cancer effects of CuNPs. IC50 of CuNPs was 322, 365, 247, and 273 on NCI-H660, DU 145, LNCaP clone FGC, and LNCaP clone FGC-Luc2 prostate cancer cells. CuNPs containing Pistacia khinjuk were found to possess noteworthy anti-prostate carcinoma characteristics and presented excellent antioxidant potentials, as highlighted by this study.

High-dose vitamin D to attenuate bone loss in patients with prostate cancer on androgen deprivation therapy: A phase 2 RCT.

Androgen deprivation therapy (ADT) inhibits prostate cancer growth. However, ADT causes loss of bone mineral density (BMD) and an increase in fracture risk; effective interventions for ADT-induced bone loss are limited. A phase 2 randomized controlled trial investigated the feasibility, safety, and preliminary efficacy of high-dose weekly vitamin D (HDVD, 50,000 IU/week) versus placebo for 24 weeks in patients with prostate cancer receiving ADT, with all subjects receiving 600 IU/day vitamin D and 1000 mg/day calcium. Participants were ≥60 years (mean years, 67.7), had a serum 25-hydroxyvitamin D level <32 ng/mL, and initiated ADT within the previous 6 months. At baseline and after intervention, dual-energy x-ray absorptiometry was used to assess BMD, and levels of bone cell, bone formation, and resorption were measured. The HDVD group (N=29) lost 1.5% BMD at the total hip vs. 4.1% for the low-dose group (N=30; p=.03) and 1.7% BMD at the femoral neck vs. 4.4% in the low-dose group (p=.06). Stratified analyses showed that, for those with baseline 25-hydroxyvitamin D level <27 ng/mL, the HDVD group lost 2.3% BMD at the total hip vs 7.1% for the low-dose group (p<.01). Those in the HDVD arm showed significant changes in parathyroid hormone (p<.01), osteoprotegerin (p<0.01), N-terminal telopeptide of type 1 collagen (p<0.01) and C-terminal telopeptide of type 1 collagen (p<0.01). No difference in adverse events or toxicity was noted between the groups. HDVD supplementation significantly reduced hip and femoral neck BMD loss, especially for patients with low baseline serum 25-hydroxyvitamin D levels, although demonstrating safety and feasibility in prostate cancer patients on ADT.

Abstract 7300: Synergistic inhibition of prostate cancer growth by the combination of xanthohumol and ursolic acid

Abstract Within the United States, prostate cancer (PCa) is the most commonly diagnosed non-cutaneous cancer, and approximately 1 in 8 men will receive a diagnosis in their lifetime. As the second leading cause of cancer deaths in American men, about 1 in 41 will die because of prostate cancer. The World Health Organization has suggested that approximately one-third of all cancer deaths are preventable, and one of the suggested means of prevention is through the increased consumption of fruits and vegetables. Fruits and vegetables contain natural compounds known as phytochemicals which possess biological activity including some anti-cancer effects. By adapting the ATP-bioluminescence assay for cell viability, our laboratory screened a natural compound library to find combinations of these compounds that may synergistically inhibit PCa cell viability. One of the combinations to emerge from this screening process was xanthohumol (XAN) and ursolic acid (UA). We examined the ability of the combination to inhibit tumor growth in a mouse HMVP2 PCa allograft tumor model. Mice were fed diets supplemented with either XAN (0.2%) or UA (0.2%) alone or the combination. Mice on the combination diet showed a significant inhibition of HMVP2 PCa tumor growth compared to mice on the single-agent diets. In addition, in vitro studies were performed to support the allograft tumor study and to further examine the mechanism of action of the combination. A cell survival assay utilizing six different PCa cell lines indicated that the combination of XAN and UA synergistically inhibited the survival of all cell lines as calculated by the Bliss index. Mechanistic studies performed in PCa cells indicate that the combination of XAN and UA inhibits oncogenic signaling better than either agent alone. Additionally, unbiased metabolomics revealed that the tumors from mice fed the combination diet had significantly less S-adenosyl-L-methionine compared to all other groups. Overall, 13 metabolic pathways were significantly different in the tumors from mice fed the combination diet compared to all other groups. The current data suggest that using a combination of XAN and UA may be a valuable chemopreventive strategy for PCa in humans. Funding: This work was supported by NIH Grant CA228404. Citation Format: Rachel Clark, Achinto Saha, Chelsea A. Friedman, Ruggiero Gorgoglione, Stefano Tiziani, John DiGiovanni. Synergistic inhibition of prostate cancer growth by the combination of xanthohumol and ursolic acid [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 7300.

Sanguinarine chloride induces ferroptosis by regulating ROS/BACH1/HMOX1 signaling pathway in prostate cancer

BackgroundSanguinarine chloride (S.C) is a benzophenanthrine alkaloid derived from the root of sanguinaria canadensis and other poppy-fumaria species. Studies have reported that S.C exhibits antioxidant, anti-inflammatory, proapoptotic, and growth inhibitory effects, which contribute to its anti-cancer properties. Recent studies suggested that the antitumor effect of S.C through inducing ferroptosis in some cancers. Nevertheless, the precise mechanism underlying the regulation of ferroptosis by S.C remains poorly understood.MethodsA small molecule library was constructed based on FDA and CFDA approved small molecular drugs. CCK-8 assay was applied to evaluate the effects of the small molecule compound on tumor cell viability. Prostate cancer cells were treated with S.C and then the cell viability and migration ability were assessed using CCK8, colony formation and wound healing assay. Reactive oxygen species (ROS) and iron accumulation were quantified through flow cytometry analysis. The levels of malondialdehyde (MDA) and total glutathione (GSH) were measured using commercially available kits. RNA-seq analysis was performed to identify differentially expressed genes (DEGs) among the treatment groups. Western blotting and qPCR were utilized to investigate the expression of relevant proteins and genes. In vivo experiments employed a xenograft mice model to evaluate the anti-cancer efficacy of S.C.ResultsOur study demonstrated that S.C effectively inhibited the viability of various prostate cancer cells. Notably, S.C exhibited the ability to enhance the cytotoxicity of docetaxel in DU145 cells. We found that S.C-induced cell death partially relied on the induction of ferroptosis, which was mediated through up-regulation of HMOX1 protein. Additionally, our investigation revealed that S.C treatment decreased the stability of BACH1 protein, which contributed to HMOX1expression. We further identified that S.C-induced ROS caused BACH1 instability by suppressing USP47expression. Moreover, In DU145 xenograft model, we found S.C significantly inhibited prostate cancer growth, highlighting its potential as a therapeutic strategy. Collectively, these findings provide evidence that S.C could induce regulated cell death (RCD) in prostate cancer cells and effectively inhibit tumor growth via triggering ferroptosis. This study provides evidence that S.C effectively suppresses tumor progression and induces ferroptosis in prostate cancer cells by targeting ROS/USP47/BACH1/HMOX1 axis.ConclusionThis study provides evidence that S.C effectively suppresses tumor progression and induces ferroptosis in prostate cancer cells by targeting the ROS/USP47/BACH1/HMOX1 axis. These findings offer novel insights into the underlying mechanism by which S.C inhibits the progression of prostate cancer. Furthermore, leveraging the potential of S.C in targeting ferroptosis may present a new therapeutic opportunity for prostate cancer. This study found that S.C induces ferroptosis by targeting the ROS/USP47/BACH1/HMOX1 axis in prostate cancer cells.Graphical

27-hydroxycholesterol and DNA damage repair: implication in prostate cancer.

We previously reported that cholesterol homeostasis in prostate cancer (PC) is regulated by 27-hydroxycholesterol (27HC) and that CYP27A1, the enzyme that converts cholesterol to 27HC, is frequently lost in PCs. We observed that restoring the CYP27A1/27HC axis inhibited PC growth. In this study, we investigated the mechanism of 27HC-mediated anti-PC effects. We employed in vitro models and human transcriptomics data to investigate 27HC mechanism of action in PC. LNCaP (AR+) and DU145 (AR-) cells were treated with 27HC or vehicle. Transcriptome profiling was performed using the Affymetrix GeneChip™ microarray system. Differential expression was determined, and gene set enrichment analysis was done using the GSEA software with hallmark gene sets from MSigDB. Key changes were validated at mRNA and protein levels. Human PC transcriptomes from six datasets were analyzed to determine the correlation between CYP27A1 and DNA repair gene expression signatures. DNA damage was assessed via comet assays. Transcriptome analysis revealed 27HC treatment downregulated Hallmark pathways related to DNA damage repair, decreased expression of FEN1 and RAD51, and induced "BRCAness" by downregulating genes involved in homologous recombination regulation in LNCaP cells. Consistently, we found a correlation between higher CYP27A1 expression (i.e., higher intracellular 27HC) and decreased expression of DNA repair gene signatures in castration-sensitive PC (CSPC) in human PC datasets. However, such correlation was less clear in metastatic castration-resistant PC (mCRPC). 27HC increased expression of DNA damage repair markers in PC cells, notably in AR+ cells, but no consistent effects in AR- cells and decreased expression in non-neoplastic prostate epithelial cells. While testing the clinical implications of this, we noted that 27HC treatment increased DNA damage in LNCaP cells via comet assays. Effects were reversible by adding back cholesterol, but not androgens. Finally, in combination with olaparib, a PARP inhibitor, we showed additive DNA damage effects. These results suggest 27HC induces "BRCAness", a functional state thought to increase sensitivity to PARP inhibitors, and leads to increased DNA damage, especially in CSPC. Given the emerging appreciation that defective DNA damage repair can drive PC growth, future studies are needed to test whether 27HC creates a synthetic lethality to PARP inhibitors and DNA damaging agents in CSPC.

Cyclosporin A inhibits prostate cancer growth through suppression of E2F8 transcription factor in a MELK‑dependent manner.

The treatment of advanced prostate cancer remains a formidable challenge due to the limited availability of effective treatment options. Therefore, it is imperative to identify promising druggable targets that provide substantial clinical benefits and to develop effective treatment strategies to overcome therapeutic resistance. Cyclosporin A (CsA) showed an anticancer effect on prostate cancer in cultured cell and xenograft models. E2F8 was identified as a master transcription factor that regulated a clinically significant CsA specific gene signature. The expression of E2F8 increased during prostate cancer progression and high levels of E2F8 expression are associated with a poor prognosis in patients with prostate cancer. MELK was identified as a crucial upstream regulator of E2F8 expression through the transcriptional regulatory network and Bayesian network analyses. Knockdown of E2F8 or MELK inhibited cell growth and colony formation in prostate cancer cells. High expression levels of E2F8 and androgen receptor (AR) are associated with a worse prognosis in patients with prostate cancer compared with low levels of both genes. The inhibition of E2F8 improved the response to AR blockade therapy. These results suggested that CsA has potential as an effective anticancer treatment for prostate cancer, while also revealing the oncogenic role of E2F8 and its association with clinical outcomes in prostate cancer. These results provided valuable insight into the development of therapeutic and diagnostic approaches for prostate cancer.

Total flavonoids of Litchi chinensis Sonn. seed inhibit prostate cancer growth in bone by regulating the bone microenvironment via inactivation of the HGFR/NF-κB signaling pathway

Ethnopharmacological relevanceLitchi chinensis Sonn. (Litchi) seed, a traditional Chinese medicine, is habitually used in the clinical treatment of prostate cancer (PCa)-induced bone pain. In our previous study, flavonoids have been identified as the active ingredient of litchi seed against PCa. However, its anti-tumor activities in bone and associated molecular mechanisms are still unclear. Aim of the studyTo investigate the effects and underlying mechanisms of total flavonoids of litchi seed (TFLS) on the growth of PCa in bone. Materials and methodsThe effect of TFLS on the growth of PCa in bone was observed using a mouse model constructed with tibial injection of luciferase-expressing RM1−luc cells. Conditioned medium (CM) from bone marrow stromal cells OP9 and CM treated with TFLS (T-CM) was used to investigate the effect on the proliferation, colony formation, and apoptosis of PCa cells (LNCaP, PC3, RM1). An antibody microarray was performed to detect cytokine expression in the supernatant fraction of OP9 cell cultures treated with TFLS or left untreated. Western blot assay was employed to determine the expression and activity of HGFR and its key downstream proteins, Akt, mTOR, NF-κB, and Erk, in PCa cells. The potential target was further verified using immunofluorescence and immunohistochemistry assays. ResultsTreatment with TFLS (80 mg/kg, 24 days) significantly suppressed the growth of RM1 cells in bone. CM from bone marrow stromal cells OP9 stimulated the proliferation and colony formation of the PCa cells as well as inhibited the apoptosis of PC3 cells, while T-CM reversed the effects mediated by OP9 cells in vitro. In an antibody array assay, TFLS regulated the majority of cytokines in OP9 cell culture supernatant, among which HGF, HGFR, IGF-1R, and PDGF-AA showed the greatest fold changes. Mechanistically, CM upregulated HGFR and promoted phosphorylation of NF-κB while T-CM induced reduction of HGFR and dephosphorylation of NF-κB in PC3 cells. Moreover, T-CM inhibited NF-κB entry into PC3 cell nuclei. Data from in vivo experiments further confirmed the inhibitory effects of TFLS on NF-κB. ConclusionTFLS suppresses the growth of PCa in bone through regulating bone microenvironment and the underlying mechanism potentially involves attenuation of the HGFR/NF-κB signaling axis.

A Pharmacological Investigation of Eph-Ephrin Antagonism in Prostate Cancer: UniPR1331 Efficacy Evidence.

The Eph kinases are the largest receptor tyrosine kinases (RTKs) family in humans. PC3 human prostate adenocarcinoma cells are a well-established model for studying Eph-ephrin pharmacology as they naturally express a high level of EphA2, a promising target for new cancer therapies. A pharmacological approach with agonists did not show significant efficacy on tumor growth in prostate orthotopic murine models, but reduced distal metastasis formation. In order to improve the comprehension of the pharmacological targeting of Eph receptors in prostate cancer, in the present work, we investigated the efficacy of Eph antagonism both in vitro and in vivo, using UniPR1331, a small orally bioavailable Eph-ephrin interaction inhibitor. UniPR1331 was able to inhibit PC3 cells' growth in vitro in a dose-dependent manner, affecting the cell cycle and inducing apoptosis. Moreover, UniPR1331 promoted the PC3 epithelial phenotype, downregulating epithelial mesenchymal transition (EMT) markers. As a consequence, UniPR1331 reduced in vitro PC3 migration, invasion, and vasculomimicry capabilities. The antitumor activity of UniPR1331 was confirmed in vivo when administered alone or in combination with cytotoxic drugs in PC3-xenograft mice. Our results demonstrated that Eph antagonism is a promising strategy for inhibiting prostate cancer growth, especially in combination with cytotoxic drugs.

Wnt Signaling and Therapeutic Resistance in Castration-Resistant Prostate Cancer.

Castration-resistant prostate cancer (CRPC) is a lethal form of prostate cancer (PCa) due to the development of resistance to androgen deprivation therapy and anti-androgens. Here, we review the emerging role of Wnt signaling in therapeutic resistance of CRPC. Convincing evidence have accumulated that Wnt signaling is aberrantly activated through genomic alterations and autocrine and paracrine augmentations. Wnt signaling plays a critical role in a subset of CRPC and in resistance to anti-androgen therapies. Wnt signaling navigates CRPC through PCa heterogeneity, neuroendocrine differentiation, DNA repair, PCa stem cell maintenance, epithelial-mesenchymal-transition and metastasis, and immune evasion. Components of Wnt signaling can be harnessed for inhibiting PCa growth and metastasis and for developing novel therapeutic strategies to manage metastatic CRPC. There are many Wnt pathway-based potential drugs in different stages of pre-clinical development and clinical trials but so far, no Wnt signaling-specific drug has been approved by FDA for clinical use in CRPC.

The SGLT2 inhibitor canagliflozin suppresses growth and enhances prostate cancer response to radiotherapy

Radiotherapy is a non-invasive standard treatment for prostate cancer (PC). However, PC develops radio-resistance, highlighting a need for agents to improve radiotherapy response. Canagliflozin, an inhibitor of sodium-glucose co-transporter-2, is approved for use in diabetes and heart failure, but is also shown to inhibit PC growth. However, whether canagliflozin can improve radiotherapy response in PC remains unknown. Here, we show that well-tolerated doses of canagliflozin suppress proliferation and survival of androgen-sensitive and insensitive human PC cells and tumors and sensitize them to radiotherapy. Canagliflozin blocks mitochondrial respiration, promotes AMPK activity, inhibits the MAPK and mTOR-p70S6k/4EBP1 pathways, activates cell cycle checkpoints, and inhibits proliferation in part through HIF-1α suppression. Canagliflozin mediates transcriptional reprogramming of several metabolic and survival pathways known to be regulated by ETS and E2F family transcription factors. Genes downregulated by canagliflozin are associated with poor PC prognosis. This study lays the groundwork for clinical investigation of canagliflozin in PC prevention and treatment in combination with radiotherapy.

Targeted inhibition of mTOR by BML-275 induces mitochondrial-mediated apoptosis and autophagy in prostate cancer

Prostate cancer (PCa) is the most frequently diagnosed cancer among men and the second leading cause of death in Western countries. Clinically, screening drugs and develop developing new therapeutics to treat PCa is of great significance. In this study, BML-275 was demonstrated to exert potent antitumor effects in PCa by antagonizing mTOR activity. In cultured PCa cells, BML-275 treatment reduced the expression levels of c-Myc and survivin, promoted the activation of p53, and thereby induced p21/cyclin D1/CDK4/6-dependent cell cycle G1/S arrest. As a result, BML-275 inhibited cellular proliferation and induced mitochondrial-mediated apoptosis. In addition, BML-275 treatment triggered autophagy. Interestingly, EACC-mediated suppression of autophagy did not affect BML-275-induced proliferation and apoptosis. Nude mouse tumorigenic experiments also confirmed that BML-275 inhibited PCa growth, induced PCa cell apoptosis and autophagy. Mechanistically, the activities of PI3K/AKT and AMPK pathways were downregulated by BML-275 treatment in vitro and in vivo. Importantly, mTOR, a common downstream negative protein of PI3K/AKT and AMPK signaling, was induced to inactivate, which may be associated with the induction of apoptosis and autophagy. The pharmacological activation of mTOR by MHY1485 abolished the induction of apoptosis and autophagy of BML-275. Molecular docking results showed that BML-275 can bind to the FKRP12-rapamycin binding site on mTOR protein, and thereby may have the same inhibitory activity on mTOR as rapamycin. Thus, these findings indicated that BML-275 induces mitochondrial-mediated apoptosis and autophagy in PCa by targeting mTOR inhibition. BML-275 may be a potential candidate for the treatment of PCa.

SHOX2 promotes prostate cancer proliferation and metastasis through disruption of the Hippo-YAP pathway

The transcription factor SHOX2 gene is critical in regulating gene expression and the development of tumors, but its biological role in prostate cancer (PCa) remains unclear. In this study, we found that SHOX2 expression was significantly raised in PCa tissues and was associated with clinicopathological features as well as disease-free survival (DFS) of PCa patients. Phenotypic tests showed that the absence of SHOX2 inhibited PCa growth and invasion, while SHOX2 overexpression promoted these effects. Mechanistically, SHOX2 was found to activate the transcription of nephronophthisis type 4 (NPHP4), a gene located downstream of SHOX2. Further analysis revealed that SHOX2 could potentially interfere with the Hippo-YAP signaling pathway through NPHP4 activation, facilitating the oncogenic behavior of PCa cells. These findings highlight SHOX2 as an oncogene in PCa and provide a basis for developing potential therapeutic approaches against this disease.

Saw Palmetto may fight prostate cancer.

Saw Palmetto may fight prostate cancer.

DNA Methyltransferase 1 Targeting Using Guadecitabine Inhibits Prostate Cancer Growth by an Apoptosis-Independent Pathway.

Epigenetic alterations such as DNA methylation and histone modifications are implicated in repressing several tumor suppressor genes in prostate cancer progression. In this study, we determined the anti-prostate cancer effect of a small molecule drug guadecitabine (gDEC) that inhibits/depletes the DNA methylation writer DNA methyltransferase 1 (DNMT1). gDEC inhibited prostate cancer cell growth and proliferation in vitro without activating the apoptotic cascade. Molecular studies confirmed DNMT1 depletion and modulated epithelial-mesenchymal transition markers E-cadherin and β-catenin in several prostate cancer cell lines (LNCaP, 22Rv1, and MDA PCa 2b). gDEC treatment also significantly inhibited prostate tumor growth in vivo in mice (22Rv1, MDA PCa 2b, and PC-3 xenografts) without any observed toxicities. gDEC did not impact the expression of androgen receptor (AR) or AR-variant 7 (AR-V7) nor sensitize the prostate cancer cells to the anti-androgen enzalutamide in vitro. In further investigating the mechanism of cytoreduction by gDEC, a PCR array analyses of 84 chromatin modifying enzymes demonstrated upregulation of several lysine-specific methyltransferases (KMTs: KMT2A, KMT2C, KMT2E, KMT2H, KMT5A), confirmed by additional expression analyses in vitro and of harvested xenografts. Moreover, gDEC treatment increased global histone 3 lysine 4 mono-and di-methylation (H3K4me1 and H3K4me2). In sum, gDEC, in addition to directly depleting the corepressor DNMT1, upregulated KMT activating epigenetic enzymes, activating terminal epithelial program activation, and prostate cancer cell cycling exits independent of apoptosis.

Abstract 2475: Bromodomain inhibitor: MT1 and its potential role in modulation of prostate cancer progression

Abstract Bromodomains (BD) are epigenetic readers of histone acetylation involved in chromatin remodeling and transcriptional regulation of protooncogene cellular myelocytomatosis (c- Myc) and other genes. Because c-Myc cannot be directly targeted by small molecular inhibitors due to disordered alpha helical structure, epigenetic targeting of c-Myc by BD inhibitors is an attractive therapeutic strategy for diseases such as prostate cancer (PC) associated with increased c-Myc upregulation with advancing disease. We studied the efficacy of MT1, a novel bivalent BD inhibitor that is 100-fold more potent than the first in class BD inhibitor JQ1, at inhibiting PC growth. We tested the effect on viability by MT-1 on PC cell lines, 3D spheroids derived from clinically annotated drug resistant patient derived xenografts (PDX), mice PDX models and corroborated the molecular mechanism of MT1 down regulation of Myc leading to downstream Myc-dependent up regulation of Protein Kinase D1 (PrKD) substrate phosphorylation by western blot. MT-1 inhibited growth of PC in castration sensitive (LNCaP) and resistant PC cells (PC-3). MT-1 treatment upregulated PrKD expression and phosphorylation of known PrKD substrates: threonine 120 (Thr-120) residues in beta-catenin and the serine 216 in Cell Division Cycle 25 (CDC25C) in PC-3 cells. Moreover, MT-1 was effective in inhibition of 3D spheroids growth at IC 50 between 0.27-0.92µM in Abiraterone, Enzalutamide, Docetaxel, Cabazitaxel metastatic castrate resistant PCa patient-derived tumor 3D spheroids. Additionally, MT1 was effective in inhibiting the tumor growth in PDX mice model. A combined intra-peritoneal administration of MT-1 with another c-Myc inhibitor (3JC48-3), an obligate c-Myc and MYC-associated protein X (MAX) heterodimerization inhibitor, increased the efficacy of inhibiting the PDX growth in mice. This study provides strong pre-clinical in vitro and in vivo evidence for advancing MT- 1 as a novel c-Myc targeting drug in PC. The MT-1 drug development will likely be highly impactful as c-Myc is dysregulated in three fourths of men with advanced PC. Citation Format: Sanjeev Shukla, Mohammed Al-Toubat, Allison H. Feibus, Ahmed Elshafei, Carlos Riveros, Nathalie Meurice, Justyna Gleba, Jonathan Chardon-Robles, Adam M. Kase, John A. Copland III, Joachim L. Petit, Teruko Osumi, K.C. Balaji. Bromodomain inhibitor: MT1 and its potential role in modulation of prostate cancer progression [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 2475.

Abstract 3441: A multivalent peptoid conjugate that inhibits therapy-resistant prostate cancer cell proliferation by modulating androgen receptor transcriptional activity

Abstract Prostate cancers adapt to androgen receptor (AR) pathway inhibitors and progress to castration resistance despite the continued expression and function of the AR. We developed a new approach to antagonize the proliferative activity of AR and inhibit castration-resistant prostate cancer (CRPC) growth using multivalent peptoid conjugates (MPCs). Our strategy is to display multiple copies of the AR antagonist, ethisterone, on a peptoid scaffold. Such a multivalent display increases the ligand’s effective local concentration, thus targeting AR with high affinity and affecting AR interactions with coregulators. Here, we report a new potent MPC called MPC309, which displays three ethisterone groups and binds to AR with nanomolar affinity. MPC309 reduces the proliferation of enzalutamide-resistant prostate cancer cells, including those harboring AR splice variants, AR ligand binding mutations, and non-canonical AR gene expression programs. We provide evidence that MPC309 enters cells via macropinocytosis, which facilitates the fluid-phase uptake of extracellular macromolecules. Macropinocytotic uptake of MPC309 enhances cancer cell-specific delivery, thus limiting systemic toxicities. MPC309 displays favorable pharmacological properties and produced significantly greater tumor suppression in xenograft studies than enzalutamide, the standard of care anti-androgen in clinical use. Mechanistically, MPC309 inhibits prostate cancer growth by eliciting a unique gene expression program through alterations in AR chromatin occupancy compared to dihydrotestosterone (DHT) or enzalutamide. Thus, MPC309 represents a novel AR antagonist that activates an AR anti-proliferative program to repress the growth of CRPC and supports further investigation of the MPC compound class for treating CRPC. Citation Format: Justine Habault, Jeffrey A. Schneider, Susan Ha, Rachel Ruoff, Joseph Puccini, Dafna Bar-Sagi, Kwok-Kin Wong, Amina Zoubeidi, Frank Claessens, David R. Wise, Susan K. Logan, Kent Kirshenbaum, Michael J. Garabedian. A multivalent peptoid conjugate that inhibits therapy-resistant prostate cancer cell proliferation by modulating androgen receptor transcriptional activity [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 3441.

Abstract 2564: Targeting IGF-1/STAT3 signaling crosstalk to inhibit prostate cancer growth and metastasis

Abstract Introduction: Prostate cancer is the most prevalent cancer in American men with unknown etiology. Signal transducer and activator of transcription 3 (STAT3) is a transcription factor, which has been implicated in the growth and metastasis of prostate cancer. Activation of STAT3 through phosphorylation modulates the expression of miR-21, an oncomir, by directly binding to their promoter region in response to various cytokines and growth factors. One such growth factor is insulin-like growth factor (IGF)-1, whose elevated levels are linked to the growth of prostate cancer. IGF-1 exerts its mitogenic effect by binding to its receptor, IGF-1R, whose expression on prostate cancer cells is also increased during neoplastic transformation. There is limited information concerning the crosstalk between IGF-1/IGF-1R and STAT3 signaling pathways which could explain their oncogenic roles in prostate cancer. In this study, we examined whether STAT3-mediated increase of miR-21 is critical for the proliferative effects of IGF-1. We further show that resveratrol, a polyphenolic antioxidant, attenuates prostate cancer growth and invasiveness through regulation of IGF-1/STAT3 pathway. Methods: In vitro studies were performed on DU145 cells, which are androgen receptor negative human prostate cancer cells. Cell viability was assessed by MTS assays, while invasion and migration of cells were tested by Boyden chamber assay and wound healing assay, respectively. Modulation of protein expression was determined by Western blotting. MiR-21 levels were determined by TaqMan assay. SiRNA transfections were performed to suppress the expression of specific proteins in order to elucidate the molecular mechanisms underlying the actions of IGF-1, STAT3 and resveratrol. Results: Acute IGF-1 treatment of DU145 cells increased phosphorylation of Akt which was correlated with the activation of STAT3. This effect of IGF-1 was through activation of IGF-1R, as siRNA-mediated knockdown of IGF-1R attenuated STAT3 activation and Akt phosphorylation. IGF-1 treatment also increased miR-21 levels and decreased the expression of its downstream protein, programmed cell death 4 (PDCD4). Effects of IGF-1 were completely attenuated by resveratrol. Furthermore, knockdown of IGF-1R and STAT3 mimicked the actions of resveratrol on DU145 cells suggesting that a signaling crosstalk exists between IGF-1 and STAT3 pathways which can be targeted to inhibit prostate cancer. Conclusion: This study demonstrates, for the first time, that IGF-1 treatment significantly activates STAT3 pathway and increases miR-21 expression in prostate cancer cells. Targeted inhibition of IGF-1-induced activation of STAT3 by resveratrol holds the promise for the development of novel therapeutic agents against prostate cancer. Citation Format: Sandeep Sheth, Raheem Al-Aameri, Vickram Ramkumar. Targeting IGF-1/STAT3 signaling crosstalk to inhibit prostate cancer growth and metastasis [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 2564.

PD04-07 THE BIVALENT BROMODOMAIN INHIBITOR; MT-1 INHIBITS PROSTATE CANCER GROWTH

You have accessJournal of UrologyCME1 Apr 2023PD04-07 THE BIVALENT BROMODOMAIN INHIBITOR; MT-1 INHIBITS PROSTATE CANCER GROWTH Sanjeev Shukla, Mohammed Al-Toubat, Carlos Riveros, Allison H. Feibus, Ahmed El-shafie, Adam M. Kase, John A. Copland, Joachim L. Petit, Nathalie Meurice, Justyna Gleba, Jonathan Chardon-Robles, Teruko Osumi, and K. C. Balaji Sanjeev ShuklaSanjeev Shukla More articles by this author , Mohammed Al-ToubatMohammed Al-Toubat More articles by this author , Carlos RiverosCarlos Riveros More articles by this author , Allison H. FeibusAllison H. Feibus More articles by this author , Ahmed El-shafieAhmed El-shafie More articles by this author , Adam M. KaseAdam M. Kase More articles by this author , John A. CoplandJohn A. Copland More articles by this author , Joachim L. PetitJoachim L. Petit More articles by this author , Nathalie MeuriceNathalie Meurice More articles by this author , Justyna GlebaJustyna Gleba More articles by this author , Jonathan Chardon-RoblesJonathan Chardon-Robles More articles by this author , Teruko OsumiTeruko Osumi More articles by this author , and K. C. BalajiK. C. Balaji More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003228.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Bromodomains (BD) are epigenetic readers of histone acetylation involved in chromatin remodeling and transcriptional regulation of protooncogene cellular myelocytomatosis (c-Myc) and other genes. Because c-Myc cannot be directly targeted by small molecular inhibitors due to disordered alpha helical structure, epigenetic targeting of c-Myc by BD inhibitors is an attractive therapeutic strategy for advanced prostate cancer (PC) associated with increased c-Myc upregulation . We studied the efficacy of MT1, a novel bivalent BD inhibitor that is 100-fold more potent than the first in class BD inhibitor JQ1, at inhibiting PC growth METHODS: We tested the effect on viability by MT-1 on PC cell lines, 3D spheroids derived from clinically annotated drug resistant patient derived xenografts (PDX), mice PDX models and corroborated the molecular mechanism of MT1 down regulation of Myc leading to downstream Myc-dependent up regulation of Protein Kinase D1 (PrKD) substrate phosphorylation by western blot. RESULTS: MT-1 inhibited growth of PC in castration sensitive (LNCaP) and resistant PC cells (PC-3). MT-1 treatment upregulated PrKD expression and phosphorylation of known PrKD substrates: threonine 120 (Thr-120) residues in beta-catenin and the serine 216 in Cell Division Cycle 25 (CDC25C) in PC-3 cells. Moreover, MT-1 was effective in inhibition of 3D spheroids growth at IC50 between 0.27-0.92µM in Abiraterone, Enzalutamide, Docetaxel, Cabazitaxel metastatic castrate resistant PCa patient-derived tumor 3D spheroids. Additionally, MT1 was effective in inhibiting the tumor growth in PDX mice model. A combined intra-peritoneal administration of MT-1 with another c-Myc inhibitor (3JC48-3), an obligate c-Myc and MYC-associated protein X (MAX) heterodimerization inhibitor, increased the efficacy of inhibiting the PDX growth in mice. CONCLUSIONS: This study provides strong pre-clinical in vitro and in vivo evidence for advancing MT-1 as a novel c-Myc targeting drug in PC. The MT-1 drug development will likely be highly impactful as c-Myc is dysregulated in three fourths of men with advanced PC. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e144 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sanjeev Shukla More articles by this author Mohammed Al-Toubat More articles by this author Carlos Riveros More articles by this author Allison H. Feibus More articles by this author Ahmed El-shafie More articles by this author Adam M. Kase More articles by this author John A. Copland More articles by this author Joachim L. Petit More articles by this author Nathalie Meurice More articles by this author Justyna Gleba More articles by this author Jonathan Chardon-Robles More articles by this author Teruko Osumi More articles by this author K. C. Balaji More articles by this author Expand All Advertisement PDF downloadLoading ...

The Journal of Urology® Home Study Course 2023 Volume 209/210.

The Journal of Urology® Home Study Course 2023 Volume 209/210.

CircDHRS3 inhibits prostate cancer cell proliferation and metastasis through the circDHRS3/miR-421/MEIS2 axis

ABSTRACT Prostate cancer is the most prevalent type of cancer among men worldwide. The importance of circular RNA (circRNA) in prostate cancer and its connection to malignancy has been steadily recognized. circRNA expression was obtained by circRNA sequencing of prostate cancer. circRNA and its function were further analysed. The results were verified by qRT-PCR, RIP assay, FISH, RNA pulldown, WB, CCK-8, colony formation assay and wound-healing assay. BALB/c Nude mice were used for xenograft hosts. Low expression of circDHRS3 was assessed in prostate cancer. Overexpression of circDHRS3 inhibited prostate cancer growth and migration in vitro. Additionally, miR-421 was shown to be the downstream target of circDHRS3, as shown by fluorescence in situ hybridization and dual-luciferase experiments. The rescue assay results for the PC3 and Du145 cell lines demonstrated that circDHRS3 inhibits prostate cancer cell lines’ ability to proliferate and metastasize by modulating MEIS2 expression through the circDHRS3/miR-421/MEIS2 axis. In vivo investigations confirmed that the overexpression of circDHRS3 could inhibit both the lung and bone metastasis of prostate cancer cells. circDHRS3 has the potential to become a biomarker and a targeted therapeutic site for prostate cancer, particularly in the malignant stage. Our study indicates that circDHRS3 inhibits prostate cancer cell proliferation and metastasis through the circDHRS3/miR-421/MEIS2 axis.