Gleason Pattern 5 May Be a Prognostic Factor in Radium-223 Treatment.

Background/Aim: Radium-223 treatment reduces the risk of death in patients with metastatic castration-resistant prostate cancer (CRPC). This study analyzed the prognostic factors in patients treated with radium-223 dichloride. Patients and Methods: Patients who received radium-223 dichloride were retrospectively analyzed. Prostate-specific antigen (PSA) response and alkaline phosphatase (ALP) decline rates were analyzed. Overall survival (OS) was evaluated using Kaplan-Meier curves, and prognostic factors for OS were assessed using Cox proportional hazards analysis. Results: Fifty-six patients were included in the study. The five-year OS rate in patients after diagnosis of CRPC was 62.2% [95% confidence interval (CI)=27.55-112.45], while the five-year OS rate in patients at the initiation of radium-223 treatment was 21.3% (95%CI=17.20-36.79). Six patients (11.1%) had a >50% PSA decline rate, and 10 (17.9%) had a >50% ALP decline rate. Cox proportional hazards analysis showed that PSA levels at the initiation of radium-223 treatment [hazard ratio (HR)=1.00; 95%CI=1.00-1.00; p=0.0054] and Gleason Pattern (GP) 5 (HR=5.42; 95%CI=1.08-27.27; p=0.0400) were associated with OS. Patients with GP 5 had a significantly poorer prognosis compared with patients with a GP ≤4. Early administration of radium-223 as a first- or second-line treatment was not associated with OS compared with late administration of radium-223 as a third-line or later treatment. Conclusion: GP 5 and high PSA levels at radium-223 initiation were associated with worse OS. Radium-223 as first- or second-line treatment was not associated with OS. Therefore, a treatment strategy for CRPC based on GP 5 is needed.

Feasibility of Indirect Treatment Comparisons Between Niraparib Plus Abiraterone Acetate and Other First-Line Poly ADP-Ribose Polymerase Inhibitor Treatment Regimens for Patients with BRCA1/2 Mutation-Positive Metastatic Castration-Resistant Prostate Cancer.

INTRODUCTION: Poly(ADP-ribose) polymerase inhibitors (PARPi) are a novel option to treat patients with metastatic castration-resistant prostate cancer (mCRPC). Niraparib plus abiraterone acetate and prednisone (AAP) is indicated for BRCA1/2 mutation-positive mCRPC. Niraparib plus AAP demonstrated safety and efficacy in the phase 3 MAGNITUDE trial (NCT03748641). In the absence of head-to-head studies comparing PARPi regimens, the feasibility of conducting indirect treatment comparisons (ITC) to inform decisions for patients with first-line BRCA1/2 mutation-positive mCRPC has been explored. METHODS: A systematic literature review was conducted to identify evidence from randomized controlled trials on relevant comparators to inform the feasibility of conducting ITCs via network meta-analysis (NMA) or population-adjusted indirect comparisons (PAIC). Feasibility was assessed based on network connectivity, data availability in the BRCA1/2 mutation-positive population, and degree of within- and between-study heterogeneity or bias. RESULTS: NMAs between niraparib plus AAP and other PARPi regimens (olaparib monotherapy, olaparib plus AAP, and talazoparib plus enzalutamide) were inappropriate due to the disconnected network, differences in trial populations related to effect modifiers, or imbalances within BRCA1/2 mutation-positive subgroups. The latter issue, coupled with the lack of a common comparator (except for olaparib plus AAP), also rendered anchored PAICs infeasible. Unanchored PAICs were either inappropriate due to lack of population overlap (vs. olaparib monotherapy) or were restricted by unmeasured confounders and small sample size (vs. olaparib plus AAP). PAIC versus talazoparib plus enzalutamide was not possible due to lack of published arm-level baseline characteristics and sufficient efficacy outcome data in the relevant population. CONCLUSION: The current randomized controlled trial evidence network does not permit robust comparisons between niraparib plus AAP and other PARPi regimens for patients with 1L BRCA-positive mCRPC. Decision-makers should scrutinize any ITC results in light of their limitations. Real-world evidence combined with clinical experience should inform treatment recommendations in this indication.

The correlation between TRIM28 expression and immune checkpoints in CRPC.

This study delves into the unexplored realm of castration-resistant prostate cancer (CRPC) by investigating the role of TRIM28 and its intricate molecular mechanisms using high-throughput single-cell transcriptome sequencing and advanced bioinformatics analysis. Our comprehensive examination unveiled dynamic TRIM28 expression changes, particularly in immune cells such as macrophages and CD8+ T cells within CRPC. Correlation analyses with TCGA data highlighted the connection between TRIM28 and immune checkpoint expression and emphasized its pivotal influence on the quantity and functionality of immune cells. Using TRIM28 knockout mouse models, we identified differentially expressed genes and enriched pathways, unraveling the potential regulatory involvement of TRIM28 in the cGAS-STING pathway. In vitro, experiments further illuminated that TRIM28 knockout in prostate cancer cells induced a notable anti-tumor immune effect by inhibiting M2 macrophage polarization and enhancing CD8+ T cell activity. This impactful discovery was validated in an in situ transplant tumor model, where TRIM28 knockout exhibited a deceleration in tumor growth, reduced proportions of M2 macrophages, and enhanced infiltration of CD8+ T cells. In summary, this study elucidates the hitherto unknown anti-tumor immune role of TRIM28 in CRPC and unravels its potential regulatory mechanism via the cGAS-STING signaling pathway. These findings provide novel insights into the immune landscape of CRPC, offering promising directions for developing innovative therapeutic strategies.

Genetically Engineered Membrane-Coated Nanoparticles for Enhanced Prostate-Specific Membrane Antigen Targeting and Ferroptosis Treatment of Castration-Resistant Prostate Cancer.

Conventional androgen deprivation therapy (ADT) targets the androgen receptor (AR) inhibiting prostate cancer (PCa) progression; however, it can eventually lead to recurrence as castration-resistant PCa (CRPC), which has high mortality rates and lacks effective treatment modalities. The study confirms the presence of high glutathione peroxidase 4 (GPX4) expression, a key regulator of ferroptosis (i.e., iron-dependent program cell death) in CRPC cells. Therefore, inducing ferroptosis in CRPC cells might be an effective therapeutic modality for CRPC. However, nonspecific uptake of ferroptosis inducers can result in undesirable cytotoxicity in major organs. Thus, to precisely induce ferroptosis in CRPC cells, a genetic engineering strategy is proposed to embed a prostate-specific membrane antigen (PSMA)-targeting antibody fragment (gy1) in the macrophage membrane, which is then coated onto mesoporous polydopamine (MPDA) nanoparticles to produce a biomimetic nanoplatform. The results indicate that the membrane-coated nanoparticles (MNPs) exhibit high specificity and affinity toward CRPC cells. On further encapsulation with the ferroptosis inducers RSL3 and iron ions, MPDA/Fe/RSL3@M-gy1 demonstrates superior synergistic effects in highly targeted ferroptosis therapy eliciting significant therapeutic efficacy against CRPC tumor growth and bone metastasis without increased cytotoxicity. In conclusion, a new therapeutic strategy is reported for the PSMA-specific, CRPC-targeting platform for ferroptosis induction with increased efficacy and safety.

Comparison of oncological outcomes of upfront androgen receptor signaling inhibitors and combined androgen blockade in Japanese patients with metastatic castration-sensitive prostate cancer.

In recent years, randomized controlled trials have demonstrated that upfront androgen receptor signaling inhibitors (ARSIs) prolong overall survival (OS) compared with androgen deprivation therapy (ADT) alone or combined androgen blockade (CAB) in patients with metastatic castration-sensitive prostate cancer (mCSPC). However, it remains unclear whether upfront ARSI is superior to CAB in Asian populations, among which the efficacy of ADT/CAB is considered relatively high. In this study, we compared the oncological outcomes of upfront ARSI and CAB in Japanese patients with mCSPC. Patients with mCSPC who underwent systemic therapy between May 2009 and October 2023 were enrolled retrospectively. Propensity score matching (PSM) was performed to compare the castration-resistant prostate cancer-free survival (CRPC-FS), cancer-specific survival (CSS), and OS between patients treated with upfront ARSI (ARSI group) and those treated with CAB (CAB group). In total, 30 and 142 patients were enrolled in the ARSI and CAB groups, respectively. After PSM (25 patients in each group), CRPC-FS was significantly longer in the ARSI group than in the CAB group (median: 36.7 vs. 12.3 months, hazard ratio: 0.44, 95% confidence interval: 0.20-0.97, p = 0.035). No significant differences were observed in CSS or OS between the two groups. In conclusion, when compared to CAB, upfront ARSI might have the potential to extend CRPC-FS among individuals in the Japanese population.

A vitamin D-based strategy overcomes chemoresistance in prostate cancer.

BACKGROUND AND PURPOSE: Castration-resistant prostate cancer (CRPC) is a common male malignancy that requires new therapeutic strategies due to acquired resistance to its first-line treatment, docetaxel. The benefits of vitamin D on prostate cancer (PCa) progression have been previously reported. This study aimed to investigate the effects of vitamin D on chemoresistance in CRPC. EXPERIMENTAL APPROACH: Structure function relationships of potent vitamin D analogues were determined. The combination of the most potent analogue and docetaxel was explored in chemoresistant primary PCa spheroids and in a xenograft mouse model derived from a patient with a chemoresistant CRPC. KEY RESULTS: Here, we show that Xe4MeCF3 is more potent than the natural ligand to induce vitamin D receptor (VDR) transcriptional activities and that it has a larger therapeutic window. Moreover, we demonstrate that VDR agonists restore docetaxel sensitivity in PCa spheroids. Importantly, Xe4MeCF3 reduces tumour growth in a chemoresistant CRPC patient-derived xenograft. In addition, this treatment targets signalling pathways associated with cancer progression in the remaining cells. CONCLUSION AND IMPLICATIONS: Taken together, these results unravel the potency of VDR agonists to overcome chemoresistance in CRPC and open new avenues for the clinical management of PCa.

Impact of proton pump inhibitors on the efficacy of androgen receptor signaling inhibitors in metastatic castration-resistant prostate cancer patients.

BACKGROUND: Proton pump inhibitors (PPIs) are widely used due to their affordability and minimal severe side effects. However, their influence on the efficacy of cancer treatments, particularly androgen receptor signaling inhibitors (ARSIs), remains unclear. This study investigates the impact of PPI usage on the treatment outcomes in patients with metastatic castration-resistant prostate cancer (mCRPC). METHODS: A total of 117 mCRPC patients were retrospectively analyzed and divided into two groups based on the concomitant use of PPI at the initiation of ARSI treatment: PPI+ (n = 38) and PPI- (n = 79). Patient characteristics, including age at ARSI treatment administered, prostate-specific antigen (PSA) value at ARSI treatment administered, International Society of Urological Pathology grade group at prostate biopsy, metastatic site at ARSI treatment administered, prior docetaxel (DTX) treatment, and type of ARSI (abiraterone acetate or enzalutamide) were recorded. Progression-free survival (PFS), overall survival (OS), and PSA response rates were compared between the two groups. Patients were further stratified by clinical background to compare PFS and OS between the two groups. RESULTS: The PPI- group exhibited significantly extended PFS and a trend toward improved OS. For PSA response (reduction of 50% or more from baseline), the rates were 62.3% and 45.9% in the PPI- group and the PPI+ group, respectively. For deep PSA response (reductions of 90% or more from baseline), the rates were 36.4% and 24.3% in the PPI- group and the PPI+ group, respectively. The effects were consistent across subgroups divided by prior DTX treatment and type of ARSI administered. CONCLUSIONS: The administration of PPIs appears to diminish the therapeutic efficacy of ARSIs in mCRPC patients. Further prospective studies are needed to confirm these findings and explore the biological mechanisms involved.

Mechanism of baicalein in treatment of castration-resistant prostate cancer based on network pharmacology and cell experiments.

Objective: Baicalein, one of the most abundant flavonoids found in Chinese herb Scutellaria baicalensis Georgi, exhibits pharmacological activities against various cancers. However, the precise pharmacological mechanism of baicalein in treating castration-resistant prostate cancer (CRPC) remains elusive. This study aimed to elucidate the potential mechanism of baicalein against CRPC through a combination of network pharmacology and experimental approaches, thereby providing new avenues for research in CRPC treatment. Methods: The pharmacological and molecular properties of baicalein were obtained using the TCMSP database. Baicalein-related targets were collected from multiple sources including SwissTargetPrediction, PharmMapper and CTD. Targets related to CRPC were acquired from DisGeNET, GeneCards, and CTD. The protein-protein interaction (PPI) was analyzed using STRING 11.5, and Cytoscape 3.7.2 software was utilized to explore the core targets of baicalein on CRPC. GO and KEGG pathway enrichment analysis were performed using DAVID database. Cell experiments were carried out to confirm the validity of the targets. Results: A total of 131 potential targets of baicalein for the treatment of CRPC were obtained. Among them, TP53, AKT1, ALB, CASP3, and HSP90AA1, etc., were recognized as core targets by Cytoscape 3.7.2. GO function enrichment analysis yielded 926 entries, including 703 biological process (BP) terms, 84 cellular component (CC) terms and 139 molecular function (MF) terms. The KEGG pathway enrichment analysis unveiled 159 signaling pathways, mainly involved in Pathways in cancer, prostate cancer, AGE-RAGE signaling pathway in diabetic complications, TP53 signaling pathway, and PI3K-Akt signaling pathway, etc. Cell experiments confirmed that baicalein may inhibit the proliferation of CRPC cells and induce cell cycle arrest in the G1 phase. This effect could be associated with the TP53/CDK2/cyclin E1 pathway. In addition, the results of CETSA suggest that baicalein may directly bind to TP53. Conclusion: Based on network pharmacology analysis and cell experiments, we have predicted and validated the potential targets and related pathways of baicalein for CRPC treatment. This comprehensive approach provides a scientific basis for elucidating the molecular mechanism underlying the action of baicalein in CRPC treatment. Furthermore, these findings offer valuable insights and serve as a reference for the research and development of novel anti-CRPC drugs.

Analysis of the immune-inflammatory indices for patients with metastatic hormone-sensitive and castration-resistant prostate cancer.

BACKGROUND: Inflammation plays a pivotal role in the progression of prostate cancer (PCa). Several immune-inflammatory indices, including neutrophil to lymphocyte ratio (NLR), derived neutrophil to lymphocyte ratio (dNLR), lymphocyte to monocyte ratio (LMR) and platelet to lymphocyte ratio (PLR), lung immune prognostic index (LIPI), systemic inflammation response index (SIRI) and systemic immune inflammation index (SII), have demonstrated their prognostic values in several solid malignancies. However, Comparisons of superiority with these seven indices' predictive efficacy within metastatic hormone-sensitive PCa (mHSPC) and metastatic castration-resistant PCa (mCRPC) remain uncertain. METHODS: We retrospectively included 407 patients diagnosed with mHSPC and 158 patients with mCRPC at West China Hospital from 2005 to 2022. The seven immune-inflammatory indices were computed based on hematological data of mHSPC at initial diagnosis and mCRPC at progression to CRPC. Prognostic value for castration-resistant prostate cancer-free survival (CFS), overall survival (OS), prostate-specific antigen progression-free survival (PSA-PFS) and prostate-specific antigen (PSA) response was assessed using Kaplan-Meier curves, Cox regression models, and chi-square tests. The predictive performance of each immune-inflammatory index was assessed using the area under the curve (AUC) in time-dependent receiver operating characteristic curve (ROC) analysis and C-index calculation. RESULTS: All seven immune-inflammatory indices were significantly associated with CFS and OS in the mHSPC cohort, as well as with PSA response, PSA-PFS, and OS in the mCRPC cohort. In the mHSPC cohort, LIPI consistently exhibited higher AUC values compared to NLR, dNLR, LMR, PLR, SII, and SIRI for predicting CFS and OS. This indicates that LIPI had a superior discriminative ability compared to the other indices (C-index of LIPI: 0.643 and 0.686 for CFS and OS, respectively). Notably, the predictive advantage of LIPI over other indices in the mHSPC stage diminished in the mCRPC stage. CONCLUSIONS: This study firstly confirmed the prognostic value of SII, SIRI and LIPI in mHSPC and mCRPC, and revealed that LIPI had a higher predictive power than NLR, dNLR, LMR, PLR, SII and SIRI in mHSPC. These non-invasive indices can enable clinicians to quickly assess the prognosis of patients.

Molecular landscape for risk prediction and personalized therapeutics of castration-resistant prostate cancer: at a glance.

Prostate cancer (PCa) is commonly occurred with high incidence in men worldwide, and many patients will be eventually suffered from the dilemma of castration-resistance with the time of disease progression. Castration-resistant PCa (CRPC) is an advanced subtype of PCa with heterogeneous carcinogenesis, resulting in poor prognosis and difficulties in therapy. Currently, disorders in androgen receptor (AR)-related signaling are widely acknowledged as the leading cause of CRPC development, and some non-AR-based strategies are also proposed for CRPC clinical analyses. The initiation of CRPC is a consequence of abnormal interaction and regulation among molecules and pathways at multi-biological levels. In this study, CRPC-associated genes, RNAs, proteins, and metabolites were manually collected and integrated by a comprehensive literature review, and they were functionally classified and compared based on the role during CRPC evolution, i.e., drivers, suppressors, and biomarkers, etc. Finally, translational perspectives for data-driven and artificial intelligence-powered CRPC systems biology analysis were discussed to highlight the significance of novel molecule-based approaches for CRPC precision medicine and holistic healthcare.

Efficacy of Enzalutamide Rechallenge for Metastatic Castration-Resistant Prostate Cancer.

OBJECTIVE: There have been several reports on rechallenge with docetaxel, cabazitaxel, abiraterone acetate, or ethinylestradiol for metastatic castration-resistant prostate cancer (mCRPC). However, the efficacy of enzalutamide rechallenge for mCRPC has not been evaluated. METHODS: We retrospectively reviewed 63 consecutive patients who received enzalutamide for mCRPC at our institution between 2014 and 2022. Eight of these patients underwent rechallenge with enzalutamide after disease progression on prior enzalutamide and other therapy and were the focus of this study. The prostate-specific antigen (PSA) response (PSA decrease >50%), PSA progression-free survival, treatment duration, overall survival (OS) after CRPC, and treatment-related adverse events were evaluated. RESULTS: PSA decline to enzalutamide rechallenge was observed in 6 patients (75%), of which 2 patients had a PSA response. The median treatment duration was 4 months (range 1-12) and median PSA progression-free survival was 3 months (range 1-7). Median OS after CRPC was 41 months. OS after CRPC was not increased in patients with a PSA response. No toxicities were worse than grade ≥3. CONCLUSION: Enzalutamide rechallenge achieved a PSA response in a quarter of our patients with mCRPC after disease progression on prior enzalutamide. However, no improvement of OS was identified in these patients.

A phase II study (AARDVARC) of AZD4635 in combination with durvalumab and cabazitaxel in patients with progressive, metastatic, castration-resistant prostate cancer.

BACKGROUND: This phase II nonrandomized study evaluated the efficacy and safety of AZD4635 in combination with durvalumab (Arm A) or durvalumab plus cabazitaxel (Arm B) in patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with docetaxel and ≥1 novel hormonal agent. PATIENTS AND METHODS: The primary endpoint was radiographic progression-free survival (rPFS) per RECIST v1.1 (soft tissue) or the Prostate Cancer Clinical Trials Working Group 3 (bone). Secondary endpoints included safety, tolerability, overall survival, confirmed prostate-specific antigen (PSA50) response, pharmacokinetics, and objective response rate. Enrollment in Arm A was stopped following a sponsor decision unrelated to safety. The study was stopped based on the planned futility analysis due to low PSA50 response in Arm B. RESULTS: In the final analysis (1 November 2021), 30 patients were treated (Arm A, n = 2; Arm B, n = 28). The median rPFS in Arm B was 5.8 months (95% confidence interval 4.2-not calculable). Median rPFS was 5.8 months versus 4.2 months for patients with high versus low blood-based adenosine signature. The most common treatment-related adverse events in Arm B were nausea (50.0%), diarrhea (46.4%), anemia and neutropenia (both 35.7%), asthenia (32.1%), and vomiting (28.6%). Overall, AZD4635 in combination with durvalumab or AZD4635 in combination with cabazitaxel and durvalumab showed limited efficacy in patients with mCRPC. CONCLUSIONS: Although the safety profile of both combinations was consistent with known safety data of the individual agents, the results of this trial do not support further development of the combinations.

GD2 and its biosynthetic enzyme GD3 synthase promote tumorigenesis in prostate cancer by regulating cancer stem cell behavior.

While better management of loco-regional prostate cancer (PC) has greatly improved survival, advanced PC remains a major cause of cancer deaths. Identification of novel targetable pathways that contribute to tumor progression in PC could open new therapeutic options. The di-ganglioside GD2 is a target of FDA-approved antibody therapies in neuroblastoma, but the role of GD2 in PC is unexplored. Here, we show that GD2 is expressed in a small subpopulation of PC cells in a subset of patients and a higher proportion of metastatic tumors. Variable levels of cell surface GD2 expression were seen on many PC cell lines, and the expression was highly upregulated by experimental induction of lineage progression or enzalutamide resistance in CRPC cell models. GD2high cell fraction was enriched upon growth of PC cells as tumorspheres and GD2high fraction was enriched in tumorsphere-forming ability. CRISPR-Cas9 knockout (KO) of the rate-limiting GD2 biosynthetic enzyme GD3 Synthase (GD3S) in GD2high CRPC cell models markedly impaired the in vitro oncogenic traits and growth as bone-implanted xenograft tumors and reduced the cancer stem cell and epithelial-mesenchymal transition marker expression. Our results support the potential role of GD3S and its product GD2 in promoting PC tumorigenesis by maintaining cancer stem cells and suggest the potential for GD2 targeting in advanced PC.

An Antibody of the Secreted Isoform of Disintegrin and Metalloprotease 9 (sADAM9) Inhibits Epithelial-Mesenchymal Transition and Migration of Prostate Cancer Cell Lines.

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.

Rare histologic transformation of a CTNNB1 (ß-catenin) mutated prostate cancer with aggressive clinical course.

BACKGROUND: Catenin (Cadherin-Associated Protein), Beta 1 (CTNNB1) genomic alterations are rare in prostate cancer (PCa). Gain-of-function mutations lead to overexpression of ß-catenin, with consequent hyperactivation of the Wnt/ß-catenin signaling pathway, implicated in PCa progression and treatment resistance. To date, successful targeted treatment options for Wnt/ß-catenin - driven PCa are lacking. METHODS: We report a rare histologic transformation of a CTNNB1 (ß-catenin) mutated metastatic castration resistant prostate cancer (mCRPC), clinically characterized by highly aggressive disease course. We histologically and molecularly characterized the liver metastatic tumor samples, as well as successfully generated patient-derived organoids (PDOs) and patient-derived xenograft (PDX) from a liver metastasis. We used the generated cell models for further molecular characterization and drug response assays. RESULTS: Immunohistochemistry of liver metastatic biopsies and PDX tumor showed lack of expression of typical PCa (e.g., AR, PSA, PSAP, ERG) or neuroendocrine markers (synaptophysin), compatible with double-negative CRPC, but was positive for nuclear ß-catenin expression, keratin 7 and 34ßE12. ERG rearrangement was confirmed by fluorescent in situ hybridization (FISH). Drug response assays confirmed, in line with the clinical disease course, lack of sensitivity to common drugs used in mCRPC (e.g., enzalutamide, docetaxel). The casein kinase 1 (CK1) inhibitor IC261 and the tankyrase 1/2 inhibitor G700-LK showed modest activity. Moreover, despite harbouring a CTNNB1 mutation, PDOs were largely insensitive to SMARCA2/4- targeting PROTAC degraders and inhibitor. CONCLUSIONS: The reported CTNNB1-mutated mCRPC case highlights the potential challenges of double-negative CRPC diagnosis and underlines the relevance of further translational research to enable successful targeted treatment of rare molecular subtypes of mCRPC.

A Real World Observational Study Characterizing Patients With Advanced Prostate Cancer Treated With or Without Androgen Receptor-Pathway-Inhibitor Therapies in Alberta, Canada.

BACKGROUND: Data are needed to improve the current understanding of clinical management and characteristics of patients with advanced prostate cancer (PC) treated with androgen receptor pathway inhibition (ARPI) therapy. METHODS: This retrospective cohort study using real-world, population-level data from Alberta, Canada included all individuals diagnosed in 2017-2020 with de novo metastatic castration-sensitive PC (mCSPC) or nonmetastatic castration-resistant PC (nmCRPC) who initiated androgen deprivation therapy (ADT). For mCSPC, patients were classified as ARPI-exposed if they received an ARPI within 180 days of initiating ADT, while patients with nmCRPC were classified as ARPI-exposed if they received an ARPI within 2 years of diagnosis. RESULTS: This study included 976 patients with mCSPC and 233 with nmCRPC of which 33.5% and 25.3% received an ARPI, respectively. The proportion of patients with mCSPC treated with an ARPI increased considerably for patients diagnosed in 2020 compared to 2017 (56.2% vs. 6.0%). In contrast, the use of ARPI to treat nmCRPC only increased marginally from 2017 to 2019/2020 (19.7% vs. 28.9%). Patients with mHSPC who were ARPI-exposed had longer median survival than patients who were ARPI-naive (38.47 (95% CI = 32.84-NA) vs. 34.19 (95% CI = 33.33-38.83; P = .03)), with a higher proportion of patients surviving to 2-years. For nmCRPC, survival was similar between ARPI-exposed and ARPI-naive. In multivariable analyses, receiving ARPI for mCSPC was associated with younger patient age, more recent diagnoses, fewer comorbidities, a higher number of metastatic sites, referral to a medical oncologist as well as receiving surgery and radiation before ADT. Receiving ARPI for nmCRPC was associated with referral to a medical oncologist, younger age, and more recent diagnoses. CONCLUSIONS: Outcome analyses in this population suggest a continued unmet clinical need and complex clinical management pathways. Given that treatment pathways have evolved considerably, continued follow-up to understand the impact of these advancements on patient outcomes are warranted.

First-Strike Rapid Predictive Dosimetry and Dose Response for 177Lu-PSMA Therapy in Metastatic Castration-Resistant Prostate Cancer.

We devised and clinically validated a schema of rapid personalized predictive dosimetry for 177Lu-PSMA-I&T in metastatic castration-resistant prostate cancer. It supersedes traditional empiric prescription by providing clinically meaningful predicted absorbed doses for first-strike optimization. Methods: Prostate-specific membrane antigen PET was conceptualized as a simulation study that captures the complex dosimetric interplay between tumor, marrow, and kidneys at a single time point. Radiation principles of fractionation, heterogeneity, normal-organ constraints (marrow, kidney), absorbed dose, and dose rate were introduced. We created a predictive calculator in the form of a free, open-source, and user-friendly spreadsheet that can be completed within minutes. Our schema achieves speed and accuracy by sampling tissue radioconcentrations (kBq/cm3) to be analyzed in conjunction with clinical input from the user that reflect dosimetric preconditions. The marrow-absorbed dose constraint was 0.217 Gy (dose rate, ≤0.0147 Gy/h) per fraction with an interfraction interval of at least 6 wk. Results: Our first 10 patients were analyzed. The first-strike mean tumor-absorbed dose threshold for any prostate-specific antigen (PSA) response was more than 10 Gy (dose rate, >0.1 Gy/h). The metastasis with the lowest first-strike tumor-absorbed dose correlated the best with the percentage decrease of PSA; its threshold to achieve hypothetical zero PSA was 20 Gy or more. Each patient's PSA doubling time can be used to personalize their unique absorbed dose-response threshold. The predicted mean first-strike prescription constrained by marrow-absorbed dose rate per fraction was 11.0 ± 4.0 GBq. Highly favorable conditions (tumor sink effect) were dosimetrically expressed as the combination of tumor-to-normal-organ ratios of more than 150 for marrow and more than 4 for kidney. Our schema obviates the traditional role of the SUV as a predictive parameter. Conclusion: Our rapid schema is feasible to implement in any busy real-world theranostics unit and exceeds today's best practice standards. Our dosimetric thresholds and predictive parameters can radiobiologically rationalize each patient's first-strike prescription down to a single becquerel. Favorable tumor-to-normal-organ ratios can be prospectively exploited by predictive dosimetry to optimize the first-strike prescription. The scientific framework of our schema may be applied to other systemic radionuclide therapies.

Increased circulating polymorphonuclear myeloid-derived suppressor cells are associated with prognosis of metastatic castration-resistant prostate cancer.

Introduction: Myeloid-derived suppressor cell (MDSC) exhibits immunosuppressive functions and affects cancer progression, but its relationship with prostate cancer remains unclear. We elucidated the association of polymorphonuclear MDSC (PMN-MDSC) and monocytic MDSC (M-MDSC) levels of the total peripheral blood mononuclear cells (PBMCs) with prostate cancer progression and evaluated their roles as prognostic indicators. Methods: We enrolled 115 patients with non-metastatic hormone-sensitive prostate cancer (nmHSPC, n = 62), metastatic hormone-sensitive prostate cancer (mHSPC, n = 23), and metastatic castration-resistant prostate cancer (mCRPC, n = 30). Subsequently, the proportions of MDSCs in each disease progression were compared. Log-rank tests and multivariate Cox regression analyses were performed to ascertain the associations of overall survival. Results: The patients with mCRPC had significantly higher PMN-MDSC percentage than those with nmHSPC and mHSPC (P = 7.73 × 10-5 and 0.0014). Significantly elevated M-MDSC levels were observed in mCRPC patients aged <70 years (P = 0.016) and with a body mass index (BMI) <25 kg/m2 (P = 0.043). The high PMN-MDSC group had notably shorter median survival duration (159 days) than the low PMN-MDSC group (768 days, log-rank P = 0.018). In the multivariate analysis including age, BMI, and MDSC subset, PMN-MDSC was significantly associated with prognosis (hazard ratios, 3.48; 95% confidence interval: 1.05-11.56, P = 0.042). Discussion: PMN-MDSC levels are significantly associated with mCRPC prognosis. Additionally, we highlight the remarkable associations of age and BMI with M-MDSC levels in mCRPC, offering novel insights into MDSC dynamics in prostate cancer progression.

Physician preferences for nonmetastatic castration-resistant prostate cancer treatment in China.

Introduction: The treatment preferences of Chinese physicians who treat nonmetastatic castration-resistant prostate cancer (nmCRPC) and how they weigh the benefits and risks of nmCRPC treatment are still unknown. This study aimed to evaluate Chinese physicians' benefit-risk treatment preferences for nmCRPC and assist in setting nmCRPC treatment goals. Methods: A paper-based discrete choice experiment (DCE) survey was administered to 80 nmCRPC-treating physicians. DCE responses were analyzed to produce the preference weight and the relative importance score for each attribute level. The marginal rate of substitution (MRS) was used to quantify the amount of overall survival (OS) physicians were willing to trade for a reduction in treatment-related adverse events (AEs). We further conducted the exploratory analysis, stratifying physicians from 5 perspectives into different subgroups and examining the treatment preferences and OS trade-off in each subgroup. Results: In terms of efficacy attributes, physicians placed greater emphasis on OS than time to pain progression. With regard to safety attributes, serious fracture was perceived as the most important AE by physicians, followed by serious fall, cognitive problems, skin rash, and fatigue. In the exploratory analysis, we found generally that physicians with less clinical practice experience and those from more economically developed regions placed more emphasis on AEs and were willing to give up more of their patients' OS to reduce the risk of AEs. Conclusion: Physicians from mainland China value the importance of minimizing treatment-related AEs when considering different treatment options for patients with nmCRPC, and they are willing to trade a substantial amount of OS to avoid AEs.

PSMA-targeted radiotheranostics in modern nuclear medicine: then, now, and what of the future?

In 1853, the perception of prostate cancer (PCa) as a rare ailment prevailed, was described by the eminent Londoner surgeon John Adams. Rapidly forward to 2018, the landscape dramatically altered. Currently, men face a one-in-nine lifetime risk of PCa, accentuated by improved diagnostic methods and an ageing population. With more than three million men in the United States alone grappling with this disease, the overall risk of succumbing to stands at one in 39. The intricate clinical and biological diversity of PCa poses serious challenges in terms of imaging, ongoing monitoring, and disease management. In the field of theranostics, diagnostic and therapeutic approaches that harmoniously merge targeted imaging with treatments are integrated. A pivotal player in this arena is radiotheranostics, employing radionuclides for both imaging and therapy, with prostate-specific membrane antigen (PSMA) at the forefront. Clinical milestones have been reached, including FDA- and/or EMA-approved PSMA-targeted radiodiagnostic agents, such as [18F]DCFPyL (PYLARIFY®, Lantheus Holdings), [18F]rhPSMA-7.3 (POSLUMA®, Blue Earth Diagnostics) and [68Ga]Ga-PSMA-11 (Locametz®, Novartis/ ILLUCCIX®, Telix Pharmaceuticals), as well as PSMA-targeted radiotherapeutic agents, such as [177Lu]Lu-PSMA-617 (Pluvicto®, Novartis). Concurrently, ligand-drug and immune therapies designed to target PSMA are being advanced through rigorous preclinical research and clinical trials. This review delves into the annals of PSMA-targeted radiotheranostics, exploring its historical evolution as a signature molecule in PCa management. We scrutinise its clinical ramifications, acknowledge its limitations, and peer into the avenues that need further exploration. In the crucible of scientific inquiry, we aim to illuminate the path toward a future where the enigma of PCa is deciphered and where its menace is met with precise and effective countermeasures. In the following sections, we discuss the intriguing terrain of PCa radiotheranostics through the lens of PSMA, with the fervent hope of advancing our understanding and enhancing clinical practice.