Search Results (116)

Background: Second-generation androgen receptor signaling inhibitors are one of the main treatment options in metastatic castration-resistant prostate cancer (mCRPC). Nonetheless, a considerable proportion show limited response to treatment, which indicates the need for convenient, easily accessible predictor biomarkers, a role suited for liquid biopsy. Methods: We conducted a PRISMA-compliant systematic review of four databases (Embase, Medline, Scopus, Web of Science) to identify all studies (observational studies and clinical trials) investigating cell-free DNA, circulating tumor cells, exosomes, and circulating RNAs as prognostic markers in metastatic castration-resistant patients starting androgen receptor signaling inhibitors. We excluded studies that evaluated combination therapies, rare histological subtypes or included nonmetastatic or castrate-sensitive disease. We also evaluated whether published papers followed reporting guidelines (REMARK, STROBE, or CONSORT for abstracts). Results: We identified a total of 123 reports, from which we identified only a few well-studied and consistent biomarkers: androgen receptor overexpression/copy number gain and splice variant 7, as well as disease burden markers (circulating tumor DNA fraction and circulating tumor cell concentration). Alterations or copy number loss in tumor suppressors PTEN, RB1, and TP53 were second in terms of quantity and consistency of evidence. However, a large majority of identified biomarkers were relatively understudied or inconsistent. We identified two potential vulnerabilities: inconsistent adherence to reporting guidelines and the under-inclusion of patients of non-Western European ancestry. Conclusions: A large number of biomarkers were linked to worse outcomes in prostate cancer; nonetheless, in most cases, the evidence is limited or inconsistent, or even contradictory. The main exceptions pertain to androgen receptor signaling and disease burden, and, to a smaller extent, to certain tumor suppressor genes. Further studies are needed to confirm their clinical utility, using clear and consistent methodologies and including patients from currently understudied populations. Full article

Background/Objective: The expression of human steroid sulfatase (STS) is upregulated in castration-resistant prostate cancer (CRPC) and is associated with resistance to anti-androgen drugs, such as enzalutamide (Enza) and abiraterone (Abi). Despite the known link between STS overexpression and therapeutic unresponsiveness, the mechanism by which STS confers this phenotype remains incompletely understood. In this study, we sought to understand how STS induces treatment resistance in advanced prostate cancer (PCa) cells by exploring its role in altering mitochondrial activity. Methods: To examine the effects of increased STS expression on mitochondrial respiration and programming, we performed RNA sequencing (RNA-seq) analysis, the Seahorse XF Mito Stress Test, and a mitochondrial Complex I enzyme activity assay in STS-overexpressing cells (C4-2B STS) and in enzalutamide-resistant CPRC cells (C4-2B MDVR). We employed SI-2, the specific chemical inhibitor of STS, on C4-2B STS and C4-2B MDVR cells and evaluated STS activity inhibition on mitochondrial molecular pathways and mitochondrial respiration. Lastly, we examined the effects of dehydroepiandrosterone sulfate (DHEAS) supplementation on C4-2B STS organoids. Results: We present evidence from the transcriptomic profiling of C4-2B STS cells that there are enriched metabolic pathway signatures involved in oxidative phosphorylation, the electron transport chain, and mitochondrial organization. Moreover, upon STS inhibition, signaling in the electron transport chain and mitochondrial organization pathways is markedly attenuated. Findings from the Seahorse XF Mito Stress Test and mitochondrial Complex I enzyme activity assay demonstrate that STS overexpression increases mitochondrial respiration, whereas the inhibition of STS by SI-2 significantly reduces the oxygen consumption rate (OCR) and Complex I enzyme activity in C4-2B STS cells. Similarly, an increased OCR and electron transport chain Complex I enzymatic activity are observed in C4-2B MDVR cells and a decreased OCR upon SI-2 inhibition. Lastly, we show that STS overexpression promotes organoid growth upon DHEAS treatment. Conclusions: Our study demonstrates STS as a key driver of metabolic reprogramming and flexibility in advanced prostate cancer. Disrupting enhanced mitochondrial respiration via STS presents a promising strategy in improving CRPC treatment. Full article

Background. Antagonists of GHRH have experimental therapeutic value, but as single agents are not likely to improve clinical outcomes, especially in advanced prostate cancer resistant to androgen deprivation therapy. Our objective is to identify anti-cancer drugs that, in combination with MIA-602 or -690 GHRH antagonists, increase cell death in all types of prostate cancer. Methods/Results. We identified inhibitors of PI3Kα or PI3Kβ that consistently increased cell death when combined with MIA-602/690. The PI3K family is critical in mediating upstream signals from receptors to downstream AKT/mTOR signaling pathways and has an important role in cancer progression. The results revealed that MIA-602/690 alone decreased androgen receptors and likely enhanced PI3K (negative feedback), which was then countered by the addition of PI3K inhibitors. Furthermore, the MIA-602/690 + PI3K inhibitor combination affected multiple signaling pathways, including apoptosis (anti-apoptotic Mcl-1L switching to pro-apoptotic Mcl-1S), proliferation (E2F1, cyclin A), PI3Kα/β, AKT, and ERK. Similar results were obtained with a more clinically relevant acetate salt form of MIA-602/690. The identification of PI3K as a drug target for prostate cancer is significant because PTEN (negative regulator of PI3K) loss of function occurs in 40–50% and PIK3CA mutation/amplification occurs in 60% of prostate cancer patients, leading to a poor prognosis. Conclusion. The ability of the MIA-602/690 + PI3K inhibitor combination to alter multiple signaling pathways may weaken the activation of adaptive mechanisms resulting from each drug and improve efficacy. Full article

Background: Metastatic prostate cancer (mPCa) is marked by heterogeneity and therapy resistance, which arise from prolonged therapy regimens. This heterogeneity is reflected in various morphologic and genetic characteristics, biomarker expression, and other molecular mechanisms, thereby contributing to the complexity of the disease. Methods: To investigate tumor heterogeneity, the effects of androgen targeting therapy (ADT) on single-cell PSA secretion was assessed by analyzing the prostate cancer cell lines using a modified ELISpot platform. The FACS and cytospin techniques were employed to understand the influence of the cell cycle on PSA secretion patterns. Additionally, a proteome array was used to identify potential biomarkers from different PCa cell lines with varying metastatic potential. Results: Among the various PCa cell lines examined, PSA expression and secretion could be visualized only from the LNCaPs. PSA secretion from circulating tumor cells (CTCs) further confirmed the validity of this assay. These LNCaPs exhibited heterogeneity in single-cell intracellular and extracellular PSA expression and in their ADT responses. LNCaPs in the G1 phase showed higher PSA secretion than in the S or G2/M phase. Apart from PSA, Cathepsin D, Progranulin, IL-8, Serpin E1, and Enolase 2 were identified as secretome markers from the metastatic PCa cell lines. Conclusions: We observed variability in PSA secretion in LNCaP in response to anti-androgen treatment and a cell cycle-dependent secretion pattern. The notable presence of Progranulin and Cathepsin D in metastatic cell lines makes them promising candidates for use in multiplexing and single-cell platforms, potentially advancing our understanding and treatment of this disease. Full article

The use of supraphysiologic testosterone, particularly when alternated with an anti-androgen agent in men with metastatic castration-resistant prostate cancer (CRPC), has demonstrated promising results in clinical trials. As the use of this therapy in clinical practice is more widely adopted, there will be a growing need to understand the mechanisms of resistance. To that end, we independently derived three separate cell models of testosterone-sensitive CRPC. From each CRPC line, high dose testosterone-resistance (HTR) lines were selected. We demonstrated the differential response of the three CRPC lines to a high dose of testosterone in vitro and in vivo. We subsequently demonstrated the resistance of the HTR lines to testosterone and varying responses to testosterone withdrawal in vivo. The heterogeneity in responses to hormonal manipulation is correlated with varying levels of androgen receptor expression within the population. Overall, we show that we have developed three models of HTR that can be used to study the mechanisms of high dose testosterone resistance and identify potential therapeutic targets. Full article

Background/Objectives: Androgen receptor (AR) expression and signaling are critical for the progression of prostate cancer and have been the therapeutic focus of prostate cancer for over 50 years. While a variety of agents have been developed to target this axis, many of these fail due to the emergent expression of AR RNA splice variants, such as AR-V7, that can signal independently of ligand binding. Other therapies, such as vaccination against prostate-specific antigens, have achieved FDA approvals but have fallen short of being incorporated as standard-of-care therapies for advanced prostate cancer. This may be due to the elevated level of immunosuppression observed in prostate cancer, which remains largely refractory to immune checkpoint blockade. Methods: We developed a vaccine targeting AR-V7, a common isoform associated with treatment resistance, and demonstrated its ability to elicit AR-V7-specific immunity and enable anti-tumor responses against AR-V7+ cancers in subcutaneous tumor models. Results: Our studies also revealed that AR-V7 expression conferred an immune suppressive phenotype that was significant in a non-AR-dependent prostate cancer model. Notably, in this model, we found that vaccination in combination with enzalutamide, an AR antagonist, suppressed these aggressive immune suppressive cancers and resulted in enhanced survival in comparison to control vaccinated and enzalutamide-treated mice. While anti-PD-1 immune checkpoint inhibition (ICI) alone slowed tumor growth, the majority of vaccinated mice that received anti-PD-1 therapy showed complete tumor elimination. Conclusions: Collectively, these results validate the importance of AR signaling in prostate cancer immune suppression and suggest the potential of AR-V7-specific vaccines as therapeutic strategies against prostate cancer, offering significant protective and therapeutic anti-tumor responses, even in the presence of androgen signaling inhibitors. Full article

Background/Objectives: Patients with non-metastatic castration-resistant prostate cancer (nmCRPC) and high-risk features frequently have progression to life-threatening metastasis without second-generation antiandrogens. This study investigated nmCRPC patients for the survival and prognostic factors from a cohort before the approved use of second-generation antiandrogens. Methods: From March 2016 to January 2021, 326 patients treated with second-generation antiandrogens for metastatic castration-resistant prostate cancer (mCRPC) or metastatic castration-sensitive prostate cancer were retrieved. Forty-four patients experiencing nmCRPC with no use of second-generation antiandrogens were reviewed. The prognostic factors, at initial diagnosis or at nmCRPC, associated with metastasis-free survival (MFS) and overall survival (OS) were analyzed. Results: The median follow-up time after nmCRPC was 46 months. The median PSA level at nmCRPC was 2.7 ng/mL. Thirty-eight of forty-four patients with nmCRPC had a PSA doubling time (PSADT) of 10 months or shorter, and the median PSADT was 4 months. The median OS from nmCRPC was 53 months, and the median interval for nmCRPC patients progressing to mCRPC was 20 months. Upon univariate analysis, PSADT < 10 months (p = 0.049) and the very-high-risk group at the initial diagnosis (p = 0.043) were associated with significantly shorter post-nmCRPC MFS. The very-high-risk group (p = 0.031) was associated with significantly worse post-nmCRPC OS. In terms of survivals from the initial diagnosis of prostate cancer, Gleason grade ≥ 8 was the only independent factor with MFS and OS. Conclusions: Without second-generation antiandrogens, nmCRPC patients with PSADT <10 months and in the initial very-high-risk group developed subsequent mCRPC in a significantly faster fashion. Patients of the very-high-risk group had shorter survival rates after nmCRPC. Full article

Castration-resistant prostate cancer (CRPC) remains a significant therapeutic challenge due to its resistance to standard androgen deprivation therapy (ADT). The emergence of androgen receptor splice variant 7 (AR-V7) has been implicated in CRPC progression, contributing to treatment resistance. Current treatments, including first-generation chemotherapy, androgen receptor blockers, radiation therapy, immune therapy, and PARP inhibitors, often come with substantial side effects and limited efficacy. Natural compounds, particularly those derived from herbal medicine, have garnered increasing interest as adjunctive therapeutic agents against CRPC. This review explores the role of AR-V7 in CRPC and highlights the promising benefits of natural compounds as complementary treatments to conventional drugs in reducing CRPC and overcoming therapeutic resistance. We delve into the mechanisms of action underlying the anti-CRPC effects of natural compounds, showcasing their potential to enhance therapeutic outcomes while mitigating the side effects associated with conventional therapies. The exploration of natural compounds offers promising avenues for developing novel treatment strategies that enhance therapeutic outcomes and reduce the adverse effects of conventional CRPC therapies. These compounds provide a safer, more effective approach to managing CRPC, representing a significant advancement in improving patient care. Full article

Metastatic prostate cancer (mPCa) is a leading cause of mortality, partly due to its resistance to anti-androgens like enzalutamide. Snail can promote this resistance by increasing full-length AR and AR-V7. High Mobility Group AT-hook 2 (HMGA2), a DNA-binding protein upstream of Snail, is crucial in proliferation and epithelial–mesenchymal transition (EMT). This study examines HMGA2’s role in enzalutamide resistance. LNCaP and 22Rv1 cells overexpressing wild-type HMGA2, but not truncated HMGA2, showed EMT. Both variants led to a decreased sensitivity to enzalutamide but not alisertib compared to Neo control cells. The overexpression of HMGA2 did not alter AR expression. Enzalutamide-resistant C4-2B cells (C4-2B MDVR) had higher HMGA2 and AR/AR variant expression than enzalutamide-sensitive C4-2B cells but remained sensitive to alisertib. The HMGA2 knockdown in C4-2B MDVR cells increased sensitivity to both enzalutamide and alisertib without changing AR expression. A clinical analysis via cBioPortal revealed HMGA2 alterations in 3% and AR alterations in 59% of patients. The HMGA2 changes were linked to treatments like enzalutamide, abiraterone, or alisertib, with amplifications more prevalent in bone, lymph node, and liver metastases. Conclusively, HMGA2 is a potential biomarker for enzalutamide resistance in mPCa, independent of Snail and AR signaling, and alisertib may be an effective treatment for mPCa that expresses HMGA2. Full article

Antiandrogen is part of the standard-of-care treatment option for metastatic prostate cancer. However, prostate cancers frequently relapse, and the underlying resistance mechanism remains incompletely understood. This study seeks to investigate whether long non-coding RNAs (lncRNAs) contribute to the resistance against the latest antiandrogen drug, darolutamide. Our RNA sequencing analysis revealed significant overexpression of LOC730101 in darolutamide-resistant cancer cells compared to the parental cells. Elevated LOC730101 levels were also observed in clinical samples of metastatic castration-resistant prostate cancer (CRPC) compared to primary prostate cancer samples. Silencing LOC730101 with siRNA significantly impaired the growth of darolutamide-resistant cells. Additional RNA sequencing analysis identified a set of genes regulated by LOC730101, including key players in the cell cycle regulatory pathway. We further demonstrated that LOC730101 promotes darolutamide resistance by competitively inhibiting microRNA miR-1-3p. Moreover, by Hi-C sequencing, we found that LOC730101 is located in a topologically associating domain (TAD) that undergoes specific gene induction in darolutamide-resistant cells. Collectively, our study demonstrates the crucial role of the lncRNA LOC730101 in darolutamide resistance and its potential as a target for overcoming antiandrogen resistance in CRPC. Full article

Androgen deprivation therapy (ADT) is the primary treatment for advanced prostate cancer (PCa). However, prolonged ADT inevitably results in therapy resistance with the emergence of the castration-resistant PCa phenotype (CRPC). Hence, there is an urgent need to explore new treatment options capable of delaying PCa progression. Hispidin (HPD) is a natural polyketide primarily derived from plants and fungi. HPD has been shown to have a diverse pharmacological profile, exhibiting anti-inflammatory, antiviral, cardiovascular and neuro-protective activities. However, there is currently no research regarding its properties in the context of PCa treatment. This research article seeks to evaluate the anti-cancer effect of HPD and determine the underlying molecular basis in both androgen-sensitive PCa and CRPC cells. Cell growth, migration, and invasion assays were performed via the MTS method, a wound healing assay and the transwell method. To investigate if HPD affected the expression of proteins, Western blot analysis was conducted. Furthermore, apoptosis was assessed by Annexin V-FITC/PI staining and Western blot analyses. HPD exhibited a favorable pharmaceutical profile to inhibit cell growth; disrupt the cell cycle; attenuate wound healing, migration and invasion; and induce apoptosis in PCa cells in vitro. The mechanistic results demonstrated that HPD reduced AR, MMP-2 and MMP-9 expression and activated the caspase-related pathway, leading to programmed cell death in PCa cells. We showed the anti-cancer effect of HPD on PCa cells and confirmed its feasibility as a novel therapeutic agent. This study provides significant insights into the delineation of the molecular mechanism of HPD in PCa cells and the development of an effective and safe therapy using HPD to eliminate PCa progression. Full article

Prostate cancer (PC) is the most common cancer diagnosed in men worldwide. Currently, castration-resistant prostate cancer (CRPC), which is resistant to androgen deprivation therapy, has a poor prognosis and is a therapeutic problem. We investigated the antitumor effects on PC of an antibody neutralizing secreted disintegrin and metalloproteinase domain-containing protein 9 (sADAM9), which is a blood-soluble form. We performed proliferation assays, wound healing assays, invasion assays, Western blot (WB), and an in vivo study in which a sADAM9 neutralizing antibody was administered intratumorally to PC-bearing mice. In invasion assays, the sADAM9 neutralizing antibody significantly inhibited invasion in all cell lines (TRAMP-C2: p = 0.00776, LNCaP: p = 0.000914, PC-3: p = 0.0327, and DU145: p = 0.0254). We examined epithelial–mesenchymal transition (EMT) markers, one of the metastatic mechanisms, in WB and showed downregulation of Slug in TRAMP-C2, LNCaP, and DU145 and upregulation of E-cadherin in TRAMP-C2 and PC-3 by sADAM9 neutralization. In mouse experiments, the sADAM9 neutralizing antibody significantly suppressed tumor growth compared to controls (1.68-fold in TRAMP-C2, 1.89-fold in LNCaP, and 2.67-fold in PC-3). These results suggested that the sADAM9 neutralizing antibody inhibits invasion, migration, and tumor growth in PC. Previous studies examined the anti-tumor effect of knockdown of total ADAM9 or sADAM9, but this study used the new technology of neutralizing antibodies for sADAM9. This may be novel because there was no animal study using a neutralizing antibody for sADAM9 to see the relationship between ADAM9 expression and prostate cancer. Full article

Background: Although metastatic hormone-sensitive prostate cancer (mHSPC) treatments have evolved, androgen deprivation therapy (ADT) remains a widely used regimen. Therefore, this study sought patients who did not progress to castration-resistant prostate cancer (CRPC) but received ADT monotherapy and factors affecting overall survival (OS) in de novo mHSPC. Methods: De novo mHSPC patients who received ADT treatment were included. ADT included luteinizing hormone-releasing hormone agonists with or without anti-androgen. The total cohort was divided into two groups relative to CRPC progression within two years. Logistic analysis was used to identify factors that did not progress CRPC within two years. Cox regression was used to assess the independent predictors for OS. Results: The total cohort was divided into the no-CRPC within two years group (n = 135) and the CRPC within two years group (n = 126). Through multivariate logistic analysis, the life expectancy (odds ratio [OR] 0.95, 95% CI 0.91–0.99, p = 0.014) and Gleason scores (≥9 vs. ≤8; OR 0.43, 95% CI 0.24–0.75, p = 0.003) were associated with the group without castration-resistant prostate cancer progression within two years. The multivariate Cox model revealed that life expectancy (hazard ratio [HR] 0.951, 95% CI 0.904–0.999, p = 0.0491), BMI (HR 0.870, 95% CI 0.783–0.967, p = 0.0101), and CCI (≥2 vs. <2; HR 2.018, 95% CI 1.103–3.693, p = 0.0227) were significant predictive factors for OS. Conclusions: Patients with long life expectancy and a Gleason score of 9 or more were more likely to develop mCRPC while alive. Patients with short life expectancy, low BMI, and worsening comorbidity were more likely to die before progressing to CRPC. Although intensified treatment is essential for oncologic outcomes in mHSPC, shared decision making is integral for patients who may not benefit from this treatment. Full article

Advanced localized prostate cancers (PC) recur despite chemotherapy, radiotherapy and/or androgen deprivation therapy. We recently reported HOXB13 lysine (K)13 acetylation as a gain-of-function modification that regulates interaction with the SWI/SNF chromatin remodeling complex and is critical for anti-androgen resistance. However, whether acetylated HOXB13 promotes PC cell survival following treatment with genotoxic agents is not known. Herein, we show that K13-acetylated HOXB13 is induced rapidly in PC cells in response to DNA damage induced by irradiation (IR). It colocalizes with the histone variant γH2AX at sites of double strand breaks (DSBs). Treatment of PCs with the Androgen Receptor (AR) antagonist Enzalutamide (ENZ) did not suppress DNA-damage-induced HOXB13 acetylation. In contrast, HOXB13 depletion or loss of acetylation overcame resistance of PC cells to ENZ and synergized with IR. HOXB13K13A mutants show diminished replication fork progression, impaired G2/M arrest with significant cell death following DNA damage. Mechanistically, we found that amino terminus regulates HOXB13 nuclear puncta formation that is essential for proper DNA damage response. Therefore, targeting HOXB13 acetylation with CBP/p300 inhibitors in combination with DNA damaging therapy may be an effective strategy to overcome anti-androgen resistance of PCs. Full article

Androgen deprivation therapy (ADT) is a primary treatment for advanced prostate cancer (PCa), but resistance often leads to castration-resistant PCa (CRPC). CRPC remains androgen receptor (AR)-dependent, and AR overexpression causes vulnerability to high doses of androgen in CRPC. Bipolar androgen therapy (BAT) refers to the periodic administration of testosterone, resulting in oscillation between supraphysiologic and near-castrate serum testosterone levels. In this study, we evaluated the efficacy of BAT against CRPC in a preclinical setting. To emulate CRPC characteristics, PCa cell lines (LNCaP, VCaP, and 22Rv1) were cultured in phenol red-free RPMI-1640 medium supplemented with 10% dextran-coated charcoal treated FBS (A− cell line). Cell viability, AR, and AR-V7 expression were evaluated using the Cell Counting Kit-8 and Western blotting. In vivo studies involved 12 castrated NOG mice injected with LNCaP/A− cells, treated with testosterone pellets or controls in 2-week cycles. Tumor sizes were measured post a 6-week treatment cycle. Bicalutamide inhibited PCa cell viability but not in the adapted cell lines. Supraphysiologic androgen levels suppressed AR-expressing PCa cell growth in vitro. In vivo, high AR-expressing LNCaP cells proliferated under castrate conditions, while BAT-treated xenografts exhibited significant growth inhibition with low Ki-67 and mitotic indexes and a high cell death index. This study provides preliminary evidence that BAT is effective for the treatment of CRPC through rapid cycling between supraphysiologic and near-castrate serum testosterone levels, inducing an anti-tumor effect. Full article