Drugs For Castration-resistant Prostate Cancer Research Articles

Lysine methyltransferase SMYD2 enhances androgen receptor signaling to modulate CRPC cell resistance to enzalutamide.

Androgen receptors (ARs) play key roles in prostate cancer (PCa) progression and castration-resistant prostate cancer (CRPC) resistance to drug therapy. SET and MYND domain containing protein 2 (SMYD2), a lysine methyltransferase, has been reported to promote tumors by transcriptionally methylating important oncogenes or tumor repressor genes. However, the role of SMYD2 in CRPC drug resistance remains unclear. In this study, we found that SMYD2 expression was significantly upregulated in PCa tissues and cell lines. High SMYD2 expression indicated poor CRPC-free survival and overall survival in patients. SMYD2 knockdown dramatically inhibited the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) potential of 22Rv1 and C4-2 cells. Conversely, ectopic overexpression of SMYD2 promoted these effects in 22Rv1 and C4-2 cells. Mechanistically, SMYD2 methylated and phosphorylated ARs to affect AR ubiquitination and proteasome degradation, which further alters the AR transcriptome in CRPC cells. Importantly, the SMYD2 inhibitor AZ505 had a synergistic therapeutic effect with enzalutamide in CRPC cells and mouse models; however, it could also re-sensitize resistant CRPC cells to enzalutamide. Our findings demonstrated that SMYD2 enhances the methylation and phosphorylation of ARs and affects AR ubiquitination and proteasome degradation to modulate CRPC cell resistance to enzalutamide, indicating that SMYD2 serves as a crucial oncogene in PCa and is an ideal therapeutic target for CRPC.

Newly developed preclinical models reveal broad-spectrum CDK inhibitors as potent drugs for CRPC exhibiting primary resistance to enzalutamide.

Androgen-deprivation therapy is a standard treatment for advanced prostate cancer. However, most patients eventually acquire resistance and progress to castration-resistant prostate cancer (CRPC). In this study, we established new CRPC cell lines, AILNCaP14 and AILNCaP15, from LNCaP cells under androgen-deprived conditions. Unlike most pre-existing CRPC cell lines, both cell lines expressed higher levels of androgen receptor (AR) and prostate-specific antigen (PSA) than parental LNCaP cells. Moreover, these cells exhibited primary resistance to enzalutamide. Since AR signaling plays a significant role in the development of CRPC, PSA promoter sequences fused with GFP were introduced into AILNCaP14 cells to conduct GFP fluorescence-based chemical screening. We identified flavopiridol, a broad-spectrum CDK inhibitor, as a candidate drug that could repress AR transactivation of CRPC cells, presumably through the inhibition of phosphorylation of AR on the serine 81 residue (pARSer81 ). Importantly, this broad-spectrum CDK inhibitor inhibited the proliferation of AILNCaP14 cells both in vitro and in vivo. Moreover, a newly developed liver metastatic model using AILNCaP15 cells revealed that the compound attenuated tumor growth of CRPC harboring highly metastatic properties. Finally, we developed a patient-derived xenograft (PDX) model of CRPC and DCaP CR from a patient presenting therapeutic resistance to enzalutamide, abiraterone, and docetaxel. Flavopiridol successfully suppressed the tumor growth of CRPC in this PDX model. Since ARSer81 was found to be phosphorylated in clinical CRPC samples, our data suggested that broad-spectrum CDK inhibitors might be a potent candidate drug for the treatment of CRPC, including those exhibiting primary resistance to enzalutamide.

LncRNA SNHG4 promotes prostate cancer cell survival and resistance to enzalutamide through a let-7a/RREB1 positive feedback loop and a ceRNA network

BackgroundProstate cancer threatens the health of men over sixty years old, and its incidence ranks first among all urinary tumors among men. Enzalutamide remains the first-line drug for castration-resistant prostate cancer, however, tumors inevitably become resistant to enzalutamide. Hence, it is of great importance to investigate the mechanisms that induce enzalutamide resistance in prostate cancer cells.MethodsBioinformatic analyzing approaches were used to identified the over-expressed genes in prostate cancer tumor tissues from three GEO datasets. qRT-PCR, western blotting and immunochemistry/In situ hybridization staining assays were performed to assess the expression of SNHG4, RRM2, TK1, AURKA, EZH2 and RREB1. Cell cycle was measured by flow cytometry. CCK-8, plate colony formation and EdU assays were performed to assess the cell proliferation. Senescence-associated β-Gal assay was used to detect the cell senescence level. γ-H2AX staining assay was performed to assess the DNA damages of PCa cells. Luciferase reporter assay and RNA immunoprecipitation assay were performed to verify the RNA-RNA interactions. Chromatin immunoprecipitation assay was performed to assess the bindings between protein and genomic DNA.ResultsWe found that RRM2 and NUSAP1 are highly expressed in PCa tumors and significantly correlated with poor clinical outcomes in PCa patients. Bioinformatic analysis as well as experimental validation suggested that SNHG4 regulates RRM2 expression via a let-7 miRNA-mediated ceRNA network. In addition, SNHG4 or RRM2 knockdown significantly induced cell cycle arrest and cell senescence, and inhibited DNA damage repair and cell proliferation, and the effects can be partially reversed by let-7a knockdown or RRM2 reoverexpression. In vitro and in vivo experiments showed that SNHG4 overexpression markedly enhanced cell resistance to enzalutamide. RREB1 was demonstrated to transcriptionally regulate SNHG4, and RREB1 was also validated to be a target of let-7a and thereby regulated by the SNHG4/let-7a feedback loop.ConclusionOur study uncovered a novel molecular mechanism of lncRNA SNHG4 in driving prostate cancer progression and enzalutamide resistance, revealing the critical roles and therapeutic potential of RREB1, SNHG4, RRM2 and let-7 miRNAs in anticancer therapy.

Comprehensive analysis of the progression mechanisms of CRPC and its inhibitor discovery based on machine learning algorithms.

Background: Almost all patients treated with androgen deprivation therapy (ADT) eventually develop castration-resistant prostate cancer (CRPC). Our research aims to elucidate the potential biomarkers and molecular mechanisms that underlie the transformation of primary prostate cancer into CRPC. Methods: We collected three microarray datasets (GSE32269, GSE74367, and GSE66187) from the Gene Expression Omnibus (GEO) database for CRPC. Differentially expressed genes (DEGs) in CRPC were identified for further analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA). Weighted gene coexpression network analysis (WGCNA) and two machine learning algorithms were employed to identify potential biomarkers for CRPC. The diagnostic efficiency of the selected biomarkers was evaluated based on gene expression level and receiver operating characteristic (ROC) curve analyses. We conducted virtual screening of drugs using AutoDock Vina. In vitro experiments were performed using the Cell Counting Kit-8 (CCK-8) assay to evaluate the inhibitory effects of the drugs on CRPC cell viability. Scratch and transwell invasion assays were employed to assess the effects of the drugs on the migration and invasion abilities of prostate cancer cells. Results: Overall, a total of 719 DEGs, consisting of 513 upregulated and 206 downregulated genes, were identified. The biological functional enrichment analysis indicated that DEGs were mainly enriched in pathways related to the cell cycle and metabolism. CCNA2 and CKS2 were identified as promising biomarkers using a combination of WGCNA, LASSO logistic regression, SVM-RFE, and Venn diagram analyses. These potential biomarkers were further validated and exhibited a strong predictive ability. The results of the virtual screening revealed Aprepitant and Dolutegravir as the optimal targeted drugs for CCNA2 and CKS2, respectively. In vitro experiments demonstrated that both Aprepitant and Dolutegravir exerted significant inhibitory effects on CRPC cells (p < 0.05), with Aprepitant displaying a superior inhibitory effect compared to Dolutegravir. Discussion: The expression of CCNA2 and CKS2 increases with the progression of prostate cancer, which may be one of the driving factors for the progression of prostate cancer and can serve as diagnostic biomarkers and therapeutic targets for CRPC. Additionally, Aprepitant and Dolutegravir show potential as anti-tumor drugs for CRPC.

KIF14 mediates cabazitaxel-docetaxel cross-resistance in advanced prostate cancer by promoting AKT phosphorylation

Docetaxel is a first-line chemotherapy drug for castration-resistant prostate cancer (CRPC); yet, some CRPC patients develop docetaxel drug resistance. Cabazitaxel is approved in the post-docetaxel treatment setting. However, recent studies suggested cross-resistance between the development of drug resistance and current treatments. In this study, we used docetaxel-resistant cell lines DU145/DTX50 and PC-3/DTX30 to measure the responses to cabazitaxel. Our findings demonstrated that docetaxel resistance could lead to cross-resistance to cabazitaxel. After docetaxel-resistant cells were treated with cabazitaxel, transcriptome analysis was performed, and the results were analyzed in combination with survival analysis and correlation analysis with Gleason score to screen the cross-resistance genes. The continuously increased expression of kinesin family member 14 (KIF14) was identified as the main cause of cross-resistance to cabazitaxel in docetaxel-resistant cells. Silencing the expression of KIF14 could restore the sensitivity of resistant PCa cells to docetaxel and cabazitaxel, attenuate proliferation and promote apoptosis of the resistant PCa cells. Notably, the depressed expression of KIF14 inhibited the phosphorylation of Akt located downstream. In summary, KIF14 mediates the cross-resistance between docetaxel and cabazitaxel, and targeting KIF14 could be an effective measurement for reversing docetaxel or cabazitaxel chemotherapy failure or enhancing the anti-tumor effects of docetaxel or cabazitaxel.

Recent advances in prostate cancer: WNT signaling, chromatin regulation, and transcriptional coregulators.

Prostate cancer is one of the most common diseases in men worldwide. Surgery, radiation therapy, and hormonal therapy are effective treatments for early-stage prostate cancer. However, the development of castration-resistant prostate cancer has increased the mortality rate of prostate cancer. To develop novel drugs for castration-resistant prostate cancer, the molecular mechanisms of prostate cancer progression must be elucidated. Among the signaling pathways regulating prostate cancer development, recent studies have revealed the importance of noncanonical wingless-type MMTV integration site family (WNT) signaling pathways, mainly that involving WNT5A, in prostate cancer progression and metastasis; however, its role remains controversial. Moreover, chromatin remodelers such as the switch/sucrose nonfermentable (SWI/SNF) complex and chromodomain helicase DNA-binding proteins 1 also play important roles in prostate cancer progression through genome-wide gene expression changes. Here, we review the roles of noncanonical WNT signaling pathways, chromatin remodelers, and epigenetic enzymes in the development and progression of prostate cancer.

Synthesis and evaluation of 7-(3-aminopropyloxy)-substituted flavone analogue as a topoisomerase IIα catalytic inhibitor and its sensitizing effect to enzalutamide in castration-resistant prostate cancer cells

Prostate cancer patients primarily receive androgen receptor (AR)-targeted drugs as a primary treatment option because prostate cancer is associated with highly activated AR signaling. AR amplification made prostate cancer cells viable under treatment of AR-targeted therapy, leading to castration resistance. AR amplification was more common in enzalutamide-resistant patients. As a strategy to overcome castration resistance and to improve the efficacy of enzalutamide, second-generation nonsteroidal antiandrogen drugs for castration-resistant prostate cancer (CRPC) including topoisomerase II (topo II) poisons such as etoposide and mitoxantrone, have been administered in combination with enzalutamide. In the present study, it was confirmed that amplification of topo IIα, but not I and IIβ, was directly and proportionally associated with poor clinical outcome of Prostate cancer. Among a novel series of newly designed and synthesized 7-(3-aminopropyloxy)-substituted flavone analogues, compound 6, the most potent derivative, was further characterized and identified as a topo IIα catalytic inhibitor that intercalates into DNA and binds to the DNA minor groove with better efficacy and less genotoxicity than etoposide, a topo II poison. Compound 6 showed remarkable efficacy in inhibiting AR-negative CRPC cell growth and sensitizing activity to enzalutamide in AR-positive CRPC cells, thus confirming the potential of topo IIα catalytic inhibitor to overcome resistance to androgen deprivation therapy.

Antiandrogenic Effects of a Polyphenol in Carex kobomugi through Inhibition of Androgen Synthetic Pathway and Downregulation of Androgen Receptor in Prostate Cancer Cell Lines.

Prostate cancer (PC) represents the most common cancer disease in men. Since high levels of androgens increase the risk of PC, androgen deprivation therapy is the primary treatment; however this leads to castration-resistant PC (CRPC) with a poor prognosis. The progression to CRPC involves ectopic androgen production in the adrenal glands and abnormal activation of androgen signaling due to mutations and/or amplification of the androgen receptor (AR) as well as activation of androgen-independent proliferative pathways. Recent studies have shown that adrenal-derived 11-oxygenated androgens (11-ketotestosterone and 11-ketodihydrotestosterone) with potencies equivalent to those of traditional androgens (testosterone and dihydrotestosterone) are biomarkers of CRPC. Additionally, dehydrogenase/reductase SDR family member 11 (DHRS11) has been reported to be a 17β-hydroxysteroid dehydrogenase that catalyzes the production of the 11-oxygenated and traditional androgens. This study was conducted to evaluate the pathophysiological roles of DHRS11 in PC using three LNCaP, C4-2 and 22Rv1 cell lines. DHRS11 silencing and inhibition resulted in suppression of the androgen-induced expression of AR downstream genes and decreases in the expression of nuclear AR and the proliferation marker Ki67, suggesting that DHRS11 is involved in androgen-dependent PC cell proliferation. We found that 5,7-dihydroxy-8-methyl-2-[2-(4-hydroxyphenyl)ethenyl]-4H-1-benzopyran-4-one (Kobochromone A, KC-A), an ingredient in the flowers of Carex kobomugi, is a novel potent DHRS11 inhibitor (IC50 = 0.35 μM). Additionally, KC-A itself decreased the AR expression in PC cells. Therefore, KC-A suppresses the androgen signaling in PC cells through both DHRS11 inhibition and AR downregulation. Furthermore, KC-A enhanced the anticancer activity of abiraterone, a CRPC drug, suggesting that it may be a potential candidate for the development of drugs for the prevention and treatment of CRPC.

RETRACTED ARTICLE: Targeting KDM4A-AS1 represses AR/AR-Vs deubiquitination and enhances enzalutamide response in CRPC

Castration-resistant prostate cancer (CRPC) is a highly malignant type of advanced cancer resistant to androgen deprivation therapy. One of the important mechanisms for the development of CRPC is the persistent imbalanced regulation of AR and AR splice variants (AR/AR-Vs). In this study, we reported KDM4A-AS1, a recently discovered lncRNA, as a tumor promoter that was significantly increased in CRPC cell lines and cancer tissues. Depletion of KDM4A-AS1 significantly reduced cell viability, proliferation, migration in vitro, and tumor growth in vivo. We found that by binding to the NTD domain, KDM4A-AS1 enhances the stability of USP14-AR/AR-Vs complex, and promoted AR/AR-Vs deubiquitination to protect it from MDM2-mediated ubiquitin-proteasome degradation. Moreover, KDM4A-AS1 was found to enhance CRPC drug resistance to enzalutamide by repressing AR/AR-Vs degradation; antisense oligonucleotide drugs targeting KDM4A-AS1 significantly reduced the growth of tumors with enzalutamide resistance. Taken together, our results indicated that KDM4A-AS1 played an important role in the progression of CRPC and enzalutamide resistance by regulating AR/AR-Vs deubiquitination; targeting KDM4A-AS1 has broad clinical application potential.

LncRNA PCBP1-AS1-mediated AR/AR-V7 deubiquitination enhances prostate cancer enzalutamide resistance

The refractory of castration-resistant prostate cancer (CRPC) is mainly reflected in drug resistance. The current research on the resistance mechanism of CRPC is still in its infancy. In this study, we revealed for the first time the key role of LncRNA PCBP1-AS1 in CRPC drug resistance. Through detailed in vivo and in vitro studies, we found that PCBP1-AS1 may enhance the deubiquitination of AR/AR-V7 by stabilizing the USP22-AR/AR-V7 complex, thereby preventing AR/AR-V7 from being degraded through the ubiquitin–proteasome pathway. Targeting PCBP1-AS1 can significantly restore the drug sensitivity of enzalutamide-resistant tumors in vivo and in vitro. Our research further expands the function of LncRNA in castration-resistant prostate cancer, which may provide new potential for clinical diagnosis and targeted therapy.

COST ANALYSIS OF ANDROGEN DEPRIVATION THERAPY AND DRUGS FOR CASTRATION-RESISTANT PROSTATE CANCER

(Purpose) Recently, new effective drugs for the treatment of castration-resistant prostate cancer (CRPC) have been developed. Although they are expected to prolong the survival time of patients with advanced prostate cancer, they may result in an economic burden. In this study, we determined the treatment results and the cost of CRPC drugs. (Methods) From 2014 to 2017, patients who were unfit for curative therapy were enrolled in this study. First, they received androgen deprivation therapy (ADT) by surgical or chemical castration. Once castration-sensitive cancer progressed to castration-resistant cancer, CRPC drugs, such as docetaxel, cabazitaxel, abiraterone and enzalutamide, were administered sequentially. In elderly or fragile patients, drug doses were often reduced to minimize their toxicity. The total costs of drugs for castration-sensitive and castration-resistant cancers were calculated, and the results were evaluated. (Results) Prostate biopsies detected prostate cancer in 257 patients. Eighty-one patients were treated with ADT, and 56 of the cancers were metastatic or showed a high prostate specific antigen level (>100 ng/ml). Thirty patients out of the 56 with advanced cancers developed CRPC, and the median time to CRPC was 10 months (range, 3-39). Drugs targeting CRPC were administered in 25 patients for a median duration of 20 months (range, 3-50). During the median observation period of 48 months (range, 13-75), 15 patients died of prostate cancer. The median annual cost of drugs for castration-sensitive cancer was 234,000 Japanese yen (2,187 US dollars) [range, 50,000-315,000 yen (467-2,943 US dollars) ]. In contrast, the median annual cost of drugs for CRPC was 2,041,000 yen (19,075 US dollars) [range, 346,000-5,017,000 yen (3,230-46,886 US dollars) ]. (Conclusions) Advanced prostate cancer tended to rapidly progress to CRPC, which required a sequence of expensive drugs for treatment. Early diagnosis preventing the development of advanced prostate cancer is desirable to reduce the economic burden for the health insurance system.

Sequential therapy of abiraterone and enzalutamide in castration-resistant prostate cancer: a systematic review and meta-analysis.

This systematic review and meta-analysis aimed to assess the prognostic value of sequential of abiraterone (ABI) and enzalutamide (ENZ) therapy in patients with castration-resistant prostate cancer (CRPC). PUBMED, Web of Science, Cochrane Library, and Scopus databases were searched for articles published prior to December 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. Studies were deemed eligible if they compared overall survival (OS), combined progression-free survival (PFS), combined prostate specific antigen (PSA)-PFS, and PSA response rates in CRPC patients receiving sequential ABI/ENZ or vice versa. PSA response to both the first and second agents was defined as a >50% decrease in PSA achieved with each of these agents. Formal meta-analyses were performed for these outcomes. Ten studies with 1096 patients were eligible for the systematic review and eight studies with 643 patients for the meta-analysis. The ABI-to-ENZ sequence was significantly associated with better PFS (pooled hazard ratio (HR): 0.62, 95% confidential interval (CI): 0.49-0.78, P < 0.001), and PSA-PFS (pooled HR: 0.48, 95% CI: 0.38-0.61, P < 0.001) than the ENZ-to-ABI sequence. PSA response rates of both agents were significantly better with the ABI-to-ENZ sequence (risk ratio: 0.21, 95% CI: 0.09-0.47, P < 0.001). In contrast, treatment sequence was not significantly associated with OS (pooled HR: 0.77, 95% CI: 0.59-1.01, P = 0.055). ABI-to-ENZ sequential therapy in patients with CRPC was associated with better PFS, PSA-PFS, and PSA response rates. Regardless of sequencing, response to drug therapy was transient for both ABI and ENZ when either agent was used as a secondary therapy. Despite this, treatment sequencing is important to achieve the maximum possible benefit from available drugs in CRPC.

Identification of Core Genes and Potential Drugs for Castration-Resistant Prostate Cancer Based on Bioinformatics Analysis.

Prostate cancer (PCa) is a common malignant tumor in elderly men worldwide. Most primary PCas inevitably progress into castration-resistant prostate cancer (CRPC) after androgen deprivation therapy. The mechanisms contributing to this progression are still controversial. In this study, functional module genes, DNA methylations, core regulators, and potential drugs in primary PCa and CRPC were explored by integrating a series of bioinformatics analyses. First, 588 differentially expressed genes (DEGs) were identified. Combined with related genes, protein-protein interaction networks were constructed, and 22 and 14 significant modules were identified in primary PCa and CRPC, respectively. More DEGs were identified in differentially methylated genes in CRPC modules. The hub genes in CRPC included CDC20 and CDK1. Moreover, core noncoding RNAs and transcription factors that significantly regulate CRPC modules were identified, including TUG1, MALAT1, E2F3, and MED1. Finally, the prediction of potential drugs for primary PCa and CRPC was also performed. Exisulind and phosphodiesterase-4 inhibitors were predicted as potential drugs for CRPC. The results of this study provide a new way for biologists and pharmacists to understand the potential molecular mechanisms of CRPC and also provide valuable references for drug redirection and new drug development for PCa.

Regression of castration-resistant prostate cancer by a novel compound QW07 targeting androgen receptor N-terminal domain.

Androgen deprivation therapy (ADT) via surgical or chemical castration frequently fails to halt lethal castration-resistant prostate cancer (CRPC), which is induced by multiple mechanisms involving constitutive androgen receptor (AR) splice variants, AR mutation, and/or de novo androgen synthesis. The AR N-terminal domain (NTD) possesses most transcriptional activity and is proposed as a potential target for CRPC drug development. We constructed a screening system targeting AR-NTD transcription activity to screening a compound library and identified a novel small molecule compound named QW07. The function evaluation and mechanism investigation of QW07 were carried out in vitro and in vivo. QW07 bound to AR-NTD directly, blocked the transactivation of AR-NTD, blocked interactions between co-regulatory proteins and androgen response elements (AREs), inhibited the expression of genes downstream of AR, and inhibited prostate cancer growth in vitro and in vivo. QW07 was demonstrated as an AR-NTD-specific antagonist with the potential to inhibit both canonical and variant-mediated AR signaling to regress the CRPC xenografts and is proposed as a lead compound for a specific antagonist targeting AR-NTD.

PCN248 - USE OF CANCER DRUGS IN THE END-OF-LIFE IN MEN DYING OF CASTRATION-RESISTANT PROSTATE CANCER: POPULATION-BASED STUDY

Several new drug therapies have been approved in castration-resistant prostate cancer (CRPC) in the past decade. However little is known about their potential overuse at the end-of-life, particularly expensive novel oral drugs such as abiraterone. Cancer drug therapy use at the end-of-life has been considered an indicator of overtreatment. The study objective was to describe CRPC drug use in the last month of life of CRPC patients in Quebec. Using administrative databases from the province of Quebec in Canada, we identified patients that received medical/surgical castration treatment, received one or more CRPC drugs (chemotherapy, abiraterone, or bone-targeted therapy) and died between 2001 and 2013. CRPC drug use in the last month of life was the primary outcome. The cohort consists of 1148 CRPC patients. A total of 316 men (27.5%) received a CRPC drug in the last month of life. For those who received chemotherapy, abiraterone and bone-targeted therapy, 10.2 %, 27.8% and 31.8% received them in the last month of life, respectively. In multivariable analyses, age over 75 (odds ratio (OR) 0.75, 95% confidence interval (95%CI) 0.57-0.99), and prostate cancer diagnosis less than 12 months (OR 0.43, 95%CI 0.26-0.72) were associated with less CRPC drug use. Relative to dying in 2005-2011, dying in 2012-2013 (OR 1.60, 95%CI 1.18-2.18) was associated with CRPC drug use. In this population-based cohort, the usage of CRPC cancer drugs decreased throughout the last year of life but remained high in the last month of life. Further work needs to be done to firmly establish if this constitutes appropriate care and if it negatively impacts patient quality of life in their last days. Persistent chemotherapy, abiraterone, bone-targeted therapies, and medical castration drugs in the last month of life may be an indicator of inappropriate and expensive end-of-life care.

Understanding how prostate cancer patients value the current treatment options for metastatic castration resistant prostate cancer

Several new compounds are now available for castration resistant prostate cancer (CRPC). Individual costs range between $40,000 and $93,000 with mean survival extensions from 2.4 to 4.8 months. Currently, it remains unclear how patients with prostate cancer (PCa) value the effect of these therapies in the setting of CRPC. ObjectiveTo assess patient understanding of core cancer concepts, opinions on the cost and overall benefit of CRPC drugs, whether out-of-pocket costs would change opinions and whether patients would ultimately opt out of CRPC drug treatment for an end-of-life (EOL) premium. Patients and methodsWe conducted a qualitative survey among patients with various PCa states ranging from active surveillance to CRPC and from various familial, financial and educational demographics. Through a series of hypothetical scenarios, we extrapolated opinions on CRPC drug value, efficacy and monetary worth. We assessed patient willingness to accept an EOL ($50,000) premium in lieu of CRPC drug treatment. Statistically, chi-squared analysis and Fisher’s exact test were used when appropriate. ResultsIn total, 103 patients completed the questionnaire, one-half of whom did not understand “advanced PCa” state and more than one-third of the concept of palliative care despite multiple meetings with Urologists. Patients willingness-to-pay and proposed drug value was higher than that accepted by government when government funded, with costs exceeding $250,000 per person, but lower than that accepted by government when self-funded. A majority (60%) would accept/consider the EOL premium in the setting of CRPC. Patients with higher education were more skeptical about CRPC drug value and more likely to accept the EOL premium (P = 0.003.) ConclusionPatients have an incomplete understanding of their own disease prognosis and its therapeutic options. This ultimately influences patient decision-making. Education, income and out-of-pocket costs diminished opinion of CRPC drugs considerably. As such, an EOL premium should be considered in subsets of patients.

Additive naftopidil treatment synergizes docetaxel-induced apoptosis in human prostate cancer cells.

Docetaxel (DTX) is a standard chemotherapeutic drug for castration-resistant prostate cancer (CRPC), although adverse events are common. To overcome this problem, researchers have evaluated the efficacy of DTX treatment in combination with other drugs. Naftopidil is a tubulin-binding drug with fewer adverse events, implying the usefulness of this drug in clinical applications when combined with DTX. Here, we investigated the efficacy of additive naftopidil treatment in combination with DTX on prostate cancer (PCa) cells. The effects of combination treatment with DTX plus naftopidil were analyzed using two animal models of LNCaP cells plus PrSC xenografts (sub-renal capsule grafting) and PC-3 xenografts (intratibial injection). Combination treatment with DTX plus naftopidil significantly inhibited cell growth in LNCaP cells compared with DTX alone. Analysis of the cooperativity index (CI) showed that combination treatment exhibited additive effects on DTX-induced growth inhibition in LNCaP cells. In contrast, combination treatment showed more than an additive (synergistic) effect on DTX-induced apoptosis in LNCaP and PC-3 cells. In LNCaP cells plus PrSC xenografts, combination treatment showed synergistic effects on DTX-induced apoptosis. The synergistic effects of naftopidil on DTX-induced apoptosis were also observed in PC-3 xenografts. Our results demonstrated that additive naftopidil treatment in combination with DTX increased the efficacy of DTX for the treatment of LNCaP and PC-3 tumors in vivo. Thus, additive naftopidil treatment showed a synergistic effect on DTX-induced apoptosis in PCa cells in vitro and in vivo, suggesting that this treatment approach may yield improved clinical benefits compared with DTX alone.

SY7-3 - Treatment strategy for prostate cancer patients with bone metastases

Bone metastasis leads to bone-related events (SRE) such as pain as well as functional impairment due to fractures, and thus loss of autonomy, leading to a decrease in QOL and ADL. Among urological cancers, prostate cancer has a high frequency of bone metastasis and, coupled with a decrease in bone mineral density by androgen ablation therapy (ADT), is also an important cancer of management against <bone health>. In the current situation that several novel drugs for castration-resistant prostate cancer (CRPC) have appeared, the necessity and importance of bone management (for osteoporosis and SRE) of prostate cancer is increasing. Prostate cancer develops bone metastases in many cases as its progression. There are also many cases that exhibit only bone metastasis, and such a condition is called “bone-dominant disease” and it is indicated by Radium-223. Bone metastasis of prostate cancer is characterized by osteoblastic bone metastasis (sometimes mixed or osteolytic). There is also a very excellent blood marker called PSA in monitoring the progression of cancer. For monitoring of patients with bone metastasis, monitoring with ALP, NTx, LDH together with the PSA is important. With the advent of novel life-prolonging drugs (abiraterone/enzalutamide/Cabazitaxel), improvement of the treatment outcome of CRPC has been recognized and long-term survival is becoming possible. Bone treatment strategies such as bone modifying agents (BMA: i.e., bisphosphonate and denosumab) and Radium-223 have been developed and remarkably advanced for the treatment of bone metastasis in addition to conventional analgesics, palliative radiotherapy. In particular, BMA has been shown to be able to suppress the occurrence of SRE and it is widely used in daily practice. Early intervention to bone microenvironment may prevent visceral metastasis, which is the terminal image of prostate cancer.

Clinical development of immunotherapy for prostate cancer.

Prostate cancer is the most common cancer in men, and the second leading cause of cancer-related death in Western countries. Prostate cancer-related death occurs in patients with metastatic castration-resistant prostate cancer. Although several new drugs for castration-resistant prostate cancer have been approved, each of these has prolonged survival by just a few months. Consequently, new therapies are sorely needed. Recently, it has been recognized that immunotherapy is an effective treatment for prostate cancer patients. Several strategies, such as cancer vaccines and immune checkpoint inhibitors, have been investigated in clinical studies for prostate cancer patients. In the present review, the results of the most recent clinical studies investigating immunotherapy in prostate cancer patients are reported, and the future clinical development of immunotherapy for prostate cancer is discussed.

Abstract A35: Drug repurposing for castration resistant prostate cancer based on disease-disease relationships

Abstract Prostate cancer (PCa) ranks second in terms of cancer-related deaths among men in the United States. The primary cause is the emergence of castration resistant prostate cancer (CRPC) and subsequent metastasis and chemoresistance. There is no known cure for CRPC with a median survival rate of about 18 months. CRPC tumors are either intrinsically resistant or rapidly develop resistance to chemotherapy. Traditional approaches to drug discovery are highly specific to single targets (molecules and indications) and are time-consuming trial-and-error approaches, which are often ineffective and unsafe for humans. This approach has resulted in a dearth of novel drugs (currently less than thirty are approved each year) and the time and costs to develop and bring one to market are prohibitive ($2.6 billion in 2013). A solution is to repurpose existing drugs with known safety profiles that interact with therapeutic targets and can be rapidly deployed for use in mono and multi-drug therapies. However, there is a problem in consistently identifying high-confidence drugs for CRPC. Many computational tools have been developed for analyses of high-throughput genomics data, and these methods have led to improved understanding of cancer biology. However, despite the generation of enormous amounts of data, improved treatments and diagnostics take a long time, and a substantial amount of research is needed to translate a genomic discovery to the bedside. We have developed an integrated drug discovery/repurposing platform that analyzes compound-protein structural interaction signatures across multiple proteomes to determine drug behavior, in contrast to traditional single (or few) target approaches. The platform implements a modeling pipeline that generates an interaction between ‘all’ (currently 3,733) human approved drugs and ‘all’ (currently 48,278) proteins using our interactome docking with dynamics program to compute ~ 1 billion proteome-compound interactions. We have prospectively validated our predictions with in vitro and in vivo preclinical studies for more than 10 different diseases including immunological, metabolic, infectious and genetic indications. Recently, we applied our integrated drug discovery pipeline and found strong relationship between CRPC with breast cancer, hypertension and inflammation to repurpose human approved drugs for CRPC. We have newly identified an FDA approved drug with IC50 less than 10nM activity on LnCaP and C4-2 cell proliferation. The repurposed lead is tissue specific and its toxicity is very less compared to other chemotherapeutic agents used for cancer. Using our computational design approach of taking into account target and anti-target binding profile we are modifying and synthesizing new analogues of this potent anti-cancer human approved drug for immunomodulation without effecting anti-cancer potency. We conclude that compared to traditional single target drug discovery that is slow and error prone, interactome based drug discovery that takes into account cancer as a heterogeneous combination of other diseases will help bring anticancer drugs faster to the clinic. Citation Format: Joydeb Majumder, Travis Lantz, Jonathan Fine, Gaurav Chopra. Drug repurposing for castration resistant prostate cancer based on disease-disease relationships. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A35.