Castration-resistant Prostate Cancer Research Articles

Management of Dry Mouth Toxicity Following 177Lu-PSMA-617 Radioligand Therapy

Treatment options for patients with metastatic castration-resistant prostate cancer include use of radioligand therapy with 177Lu-PSMA-617. While 177Lu-PSMA-617 can be used to selectively target prostate cancer cells, salivary glands express PSMA on the apical lumen of the acinar epithelium. Xerostomia resulting from the use of radioligand therapy is common. Herein, we report on a case of a Common Terminology Criteria for Adverse Events version 5 grade 2 dry mouth event after administration of 177Lu-PSMA-617. The patient was managed with oral hygiene and xerostomia mitigation strategies using oral rinses.

FAP and PSMA Expression by Immunohistochemistry and PET Imaging in Castration-Resistant Prostate Cancer: A Translational Pilot Study.

Prostate-specific membrane antigen (PSMA) is a theranostic target for metastatic prostate cancer (PCa). However, castration-resistant PCa (CRPC) may lose PSMA expression after systemic therapy. Fibroblast activation protein (FAP), expressed by carcinoma-associated fibroblasts in various cancer types, including PCa, has the potential to be an alternative target. In this study, we evaluated FAP expression in CRPC to assess its potential, using PSMA as a comparison. Methods: FAP expression was assessed using immunohistochemistry in 116 CRPC tumors: 78 adenocarcinomas, 11 small cell carcinomas, and 27 anaplastic carcinomas. Correlation analysis between manual scoring and automated scoring was performed on 54 whole-slide sections of metastatic CRPC. Paired FAP and PSMA stains were assessed in tissue microarray cores of CRPC (n = 62), consisting of locally advanced CRPC (n = 9) and metastatic CRPC (n = 53). FAP and PSMA positivity was defined by an immunohistochemistry score of at least 10. To explore the correlation of PSMA and FAP inhibitor (FAPi) PET imaging and immunohistochemistry, a preliminary analysis of 4 patients included in a [68Ga]-FAPi-46 imaging trial (NCT04457232) was conducted. Results: Manual and automated scoring of FAP yielded results with strong correlations. Overall, FAP expression in CRPC was notably lower than PSMA expression (median immunoscores, 14 vs. 72; P < 0.001). Different histologic subtypes of CRPC demonstrated distinct levels of PSMA expression, whereas their FAP expression levels were comparable. Among the 19 PSMA-negative tumors, 11 (58%) exhibited FAP positivity. FAP expression levels in lymph node metastases were significantly lower than those in nonnodal metastases (P = 0.021). Liver metastases showed significant enrichment of tumors with strong FAP expression compared with nonliver lesions (P = 0.016). In the 4 clinical trial patients, the biopsied metastatic lesions showed lower uptake on FAPi PET than on PSMA PET (median SUVmax, 9.6 vs. 14.5), consistent with FAP expression that was lower than PSMA expression in the corresponding tumor biopsy samples (median immunoscores, 30 vs. 160). Conclusion: Because of the low FAP expression levels in CRPC, the utility of FAPi PET imaging may be limited. Although FAPi PET imaging may be further tested in PSMA-negative CRPC, such as small cell carcinoma, other molecular imaging modalities should be evaluated as alternative choices.

PARP inhibitors in prostate cancer: clinical applications.

Despite recent advancements in the treatment of metastatic castrate-resistant prostate cancer (mCRPC), this disease remains lethal. A novel family of targeted pharmaceuticals known as poly-ADP-ribose polymerase (PARP) inhibitors has been developed to treat mCRPC patients with homologous recombination repair (HRR) gene alterations. The FDA recently approved olaparib and rucaparib for treating mCRPC patients with HRR gene alterations. Ongoing trials are investigating combination therapies involving PARP inhibitors combined with radiation, chemotherapy, immunotherapy, and androgen receptor signaling inhibitors (ARSIs) to improve the effectiveness of PARP inhibitors and broaden the range of patients who can benefit from the treatment. This review provides an overview of the development of PARP inhibitors in prostate cancer and analyzes the mechanisms underlying their resistance.

Cutaneous and Subcutaneous Prostate-Specific Membrane Antigen-Avid Lesions.

We report the case of a 62-year-old man with metastatic castration-resistant prostate cancer with subcutaneous involvement being treated with 177Lu-prostate-specific membrane antigen (PSMA). Before treatment, he was diagnosed with 2 subcutaneous nodules in the chest wall and soft tissue edema in the pubic and inguinal regions showing PSMA avidity. Biopsy and immunohistochemistry assessment confirmed cutaneous metastases from prostate cancer. He received 3 cycles of 177Lu-PSMA, resulting in a decline in PSA levels and resolution of symptoms. This case underscores the challenging diagnosis of cutaneous metastasis from prostate cancer, especially in atypical presentations. We also reviewed all causes of PSMA-avid lesions in the skin and subcutaneous tissues.

Dysphasia: metastatic prostate cancer to the leptomeninges: a case report

BackgroundLeptomeningeal metastasis occurs in 5% of patients with prostate cancer and indicates a very poor prognosis.Case presentationA 60-year-old Caucasian male patient diagnosed with metastatic castration-resistant prostate cancer with sclerotic bone metastases and soft tissue metastases underwent multiple courses of chemotherapy and hormone therapy. The diagnosis of prostate cancer is based on elevated prostate-specific antigen levels and tissue biopsy. He subsequently presented with expressive aphasia. Nonspecific, diffuse irregular dural/pachymeningeal thickening enhancement was noted on magnetic resonance imaging. Upon evaluation by neurology, electroencephalogram was negative for an epileptiform correlate. The workup included a lumbar puncture to rule out infectious etiology. The patient’s neurological status stabilized, and he was discharged home with a plan for continued therapy with abiraterone and prednisone. Due to advanced malignancy, the patient enrolled in hospice and died 3 weeks after hospital discharge.ConclusionsCentral nervous system metastasis occurs very rarely in prostate cancer. With the increase in life expectancy and advances in oncologic therapy for prostate cancer, physicians should be aware of and consider central nervous system metastasis in men aged 50 years and above.

Abiraterone and Galeterone, Powerful Tools Against Prostate Cancer: Present and Perspective

Due to the high prostate cancer incidence worldwide, the development of different methods of treatment continues to be a hot research topic. Since its first clinical application at the beginning of the 2010s, abiraterone in the form of prodrug abiraterone acetate continues to be the most used hormone derivative in the treatment of castration-resistant prostate cancer. This is the reason behind the publication of many scientific results regarding its synthesis, biological activity, metabolism, novel designed steroid derivatives based on its structure, etc. A similar steroid compound with a heterocycle in the C17 position, called galeterone, also designed to treat prostate cancer, continues to be in clinical studies, which provides further proof of the importance of these steroid derivatives. Besides prostate cancer treatment, abiraterone showed indications for possible clinical application in the treatment of breast, ovarian, lung, kidney, salivary gland, and adrenocortical cancer, congenital adrenal hyperplasia, Cushing’s syndrome, and COVID-19, while galeterone is investigated for its use against prostate, pancreatic, and breast cancer. Herein, we report a review comprising methods of synthesis, possible clinical applications, and mechanisms of action, as well as structures and bioactivities of derivatives of these two important steroids.

Enhancing Effects of Olaparib by Alpha- and Beta-Emitting Radionuclides, X-Rays, and Ultraviolet A Light in Combination with Ortho-IodoHoechst in a Prostate Cancer Cell Model

Background: New therapeutic strategies for metastatic castration-resistant prostate cancer (mCRPC) have been developed in the past to achieve the best response rates. Most recently, the use of combination therapies has been explored to optimize patient outcomes. Poly(ADP-ribose) polymerase inhibitors (PARPi) may help to treat mCRPC more effectively. Objectives: This study aimed to determine whether the combination of a PARPi with different radiation qualities results in different levels of radiosensitization of PC-3 cells. Methods: The radiosensitizing potential of Olaparib in combination with 177Lu, 223Ra, X-rays and photodynamic therapy (PDT) using the UVA light-activated photosensitizer ortho-iodoHoechst33258 (oIH) was evaluated by determining the clonogenic survival, DNA damage and cell cycle analysis. Results: Here, we show that this combination strategy differentially sensitized PC-3 cells to different radiation qualities. The combination of 177Lu with Olaparib increased the numbers of persistent double-strand breaks (DSBs) by a factor of 3.3 and cell death in PC-3 cells. Overall, the β-emitter 177Lu indicated a higher radiosensitization efficacy compared to 223Ra, with X-rays corresponding to dose modification factors (DMF) of 1.77, 1.17 and 1.16 respectively. Even in the case of the α-emitter 223Ra, the effects were much less pronounced than for 177Lu. PARPi also showed a slight potentiation of the cytotoxic effects both in co-treatment with X-rays and with PDT. Conclusions: The results of our study indicate a potential role for Olaparib in further optimizing the PSMA radioligand therapy (PRLT) outcomes. However, further evaluation of the combination of PARPi with PRLT is needed to gain more insights into improving the benefit to patients suffering from mCRPC.

Outcomes for Patients with Metastatic Castration-Resistant Prostate Cancer and Liver Metastasis Receiving [177Lu]Lu-PSMA-617.

It is well known that patients with liver metastasis from metastatic castration-resistant prostate cancer have poor or only transient responses to many forms of systemic therapy. Data on outcomes after treatment with [177Lu]Lu-PSMA-617 (LuPSMA) are scarce. The VISION trial reports a hazard ratio for overall survival (OS) in the subgroup of patients with liver metastasis without disclosing the absolute duration of survival. Using real-world clinical data, we examined this important subgroup of patients, describing prostate-specific antigen (PSA) response and OS. Methods: A single-institution database was assembled to include all patients receiving LuPSMA at Mayo Clinic in Rochester, Minnesota, for whom treatment was initiated between March 2022 and March 2023. Baseline clinicopathologic and imaging characteristics were abstracted. Patients were then categorized by presence or absence of liver metastasis on pretreatment prostate-specific membrane antigen (PSMA) PET. PSA response and OS for the 2 groups (liver metastasis vs. no liver metastasis) were compared using χ2 testing and the Kaplan-Meier method, respectively. A multivariate Cox regression analysis was performed, including established prognostic factors. Finally, those with pretreatment circulating tumor DNA as determined in an 83-gene panel were assessed for the presence of pathogenic and likely pathogenic alterations. These findings were summarized using descriptive statistics and compared between the 2 cohorts using the Fisher exact test. Results: The overall cohort consisted of 273 patients, including 43 (15.75%) with liver metastasis on pretreatment PSMA PET/CT. The median number of cycles received was 3 (range, 1-6) for patients with liver metastasis and 5 (range, 1-6) for those without hepatic involvement. The 50% or greater reduction in PSA from baseline response rate was lower for those with liver metastasis than for those without (30.23% [13/43] vs 49.77% [106/213], P = 0.019). At a median follow-up of 10 mo (interquartile range, 9-13 mo), there was a significant difference in median OS (8.35 mo vs. not reached, P < 0.001). On multivariate analysis, the presence of liver metastasis was independently associated with shorter survival (hazard ratio, 4.06; P < 0.001). Conclusion: Our data suggest that the presence of liver metastasis predicts poorer outcomes in patients receiving LuPSMA treatment. Alternative and combination approaches should be explored to maximize the antitumor activity of radiopharmaceutical therapy in the liver.

Genetic Variations in TP53, RB1, and PTEN in a Selected Sample of Slovak Patients With Metastatic Castration-resistant Prostate Cancer.

This report aimed to present identified variants with pathogenic potential in three genes - TP53, PTEN, and RB1 - in a selected sample of patients with metastatic castration-resistant prostate cancer (mCRPC) with or without the presence of circulating tumor cells (CTCs) and splice variant AR-V7. Next generation sequencing was performed on an Illumina platform to analyse the genetic profiles of 50 patients with mCRPC. Identified variants were validated using the Integrative Genomic Viewer, and the correlation between these variants and the presence of CTC/AR-V7 was subjected to statistical analysis. The study revealed a total of 15 genetic alterations in the three examined genes. The presence of rs1042522 (TP53) in mCRPC patients was associated with a significantly reduced likelihood of AR-V7 occurrence (p<0.001), indicating a protective effect. Additionally, patients with AR-V7 showed a marked increase in prostate-specific antigen (PSA) levels. Higher PSA levels were correlated with an increased risk of AR-V7 presence. The identified genetic mutations and PSA levels have a moderate predictive ability for determining AR-V7 status.

Bone-Targeting Radionuclides in the Treatment of Metastatic Castration-Resistant Prostate Cancer: A Review on Radium-223 Chloride (Alpharadin) in Combination with Other Therapies.

Recent advances have broadened the range of therapeutic options for mCRPC, with several new treatments, including novel hormonal therapies (enzalutamide, abiraterone), chemotherapeutic agents (docetaxel, cabazitaxel), immunotherapies (sipuleucel-T), and bone targeting radiopharmaceuticals (radium-223) showing improved clinical outcomes and receiving U.S. Food and Drug Administration approval. These new treatments provide new avenues for improving patient survival and quality of life. Radium-223, a targeted alpha-emitter, specifically targets bone metastases, offering palliative benefits and a potential increase in life expectancy. The integration of radium-223 with other treatments shows promise for managing mCRPC. However, the optimal sequencing and combination of radium-223 with other therapies are still being explored, with various clinical trials investigating new therapeutic approaches. The integration of these therapies, especially to provide more effective, personalized treatment strategies, requires further investigation. A thorough literature review was conducted on current treatments for mCRPC, including chemotherapeutic agents, oral hormonal therapies targeting the androgen receptor axis, immunotherapies, and radium-223. Ongoing clinical trials investigating radium-233 in the context of other therapies for the treatment of mCRPC patients were also reviewed. Further studies should focus on determining the optimal sequencing and dosing and identifying biomarkers that predict treatment response to enhance outcomes of mCRPC patients. This review underlines the rational strategies of combining radium-223 with other therapies, investigating their impact on bone in terms of delaying skeletal-related events, and managing bone disease progression in mCRPC patients.

Effects of Concurrent Administration of Spironolactone in Veterans with Metastatic Prostate Cancer Receiving Abiraterone: A Real-World Retrospective Study.

Prostate cancer is the most common cancer in men in the United States with low survival rates once metastasized. Abiraterone is approved for use in castrate-sensitive and castrate-resistant prostate cancer and is used extensively in the Veterans Affairs (VA) healthcare system. Spironolactone, a diuretic used to treat heart failure, edema, ascites, and hypertension, may increase androgen levels and reduce effectiveness of abiraterone when used concurrently to treat prostate cancer patients. While previous case studies support this, no large epidemiology studies have been conducted. The current study utilizes the large, VA prostate cancer data core and evaluates the effect of concomitant spironolactone on efficacy of abiraterone treatment in metastatic prostate cancer patients. The study selected 18,943 veterans with metastatic prostate cancer on abiraterone treatment. Of these, 581 patients (3.1%) were also on concomitant spironolactone. The concomitant treatment group, abiraterone + spironolactone, significantly differed from the abiraterone-only group in body mass index, prevalence rates of heart failure and liver disease, and being previously treated with docetaxel. A 1:1 propensity score matching method was used to balance sample sizes and baseline traits between the two treatment groups, abiraterone versus abiraterone + spironolactone. Kaplan-Meier curves and Cox proportional hazard model were used to compare 5-year overall survival and all-cause mortality outcomes, respectively, between the two groups. After propensity score matched, the abiraterone + spironolactone group was treated with abiraterone significantly longer than the abiraterone-only group (mean ± standard deviation days 549.0 ± 552.3 vs. 435.5 ± 474.1; p = 0.0002) and had a higher 5-year overall survival rate (44% vs. 37%; p = 0.0116). Veterans with metastatic prostate cancer treated with abiraterone + spironolactone also had a lower 5-year all-cause mortality compared to those only on abiraterone (hazard ratio 0.80, 95% confidence intervals 0.61-0.96; p = 0.012). This large VA observational study suggests that concomitant use of spironolactone does not compromise cancer control or survival of metastatic prostate cancer patients treated with abiraterone.

Insufficient Effective Time of Suberanilohydroxamic Acid, a Deacetylase Inhibitor, Treatment Promotes PC3 Cell Growth.

Castration-resistant prostate cancer (CRPC) contributes mostly to prostate cancer-specific mortality, and conventional castration therapy is almost ineffective, new therapies are needed. As a new potential anti-cancer drug, histone deacetylases (HDACs) inhibitors were demonstrated to be effective in inhibiting drug-resistance cancers in preclinical studies, but the results from clinical trials on CRPC patients were disappointing, and the reasons are unknown. In this study, we investigated the effect of suberanilohydroxamic acid (SAHA), a broad-spectrum pan-HDAC inhibitor, on proliferation, apoptosis, cell cycle progression in PC3 cells, and found that, unlike significant inhibiting effects at high-dose, low-dose SAHA significantly promoted PC3 cell growth. Further colony formation assay showed that the inhibitory effect of SAHA is also dependent on the treatment time, high-dose SAHA also exhibited promoting effect on PC3 cells when the treatment time was insufficient. However, this effect was not observed in another CRPC cell line, DU145, or another HDAC inhibitor, Trichostatin A (TSA). Our results indicate that, instead of inhibitory effect, SAHA would promote PC3 cell growth if the dose is low or the treatment time is insufficient, but this effect has not been observed in other CRPC cell line or HDAC inhibitors.

Functional assessment in patients with castration-resistant prostate cancer treated with darolutamide: results from the DaroAcT study.

Androgen receptor inhibitors (ARIs) are approved for the treatment of advanced prostate cancer; however, some patients may experience symptoms and side effects that hinder their physical functioning. The Timed Up and Go (TUG) and Short Physical Performance Battery (SPPB) tests are used to assess physical functioning in older adults and are recommended assessments for patients with prostate cancer, despite lacking validation in this setting. DaroAct (NCT04157088) was an open-label, multicenter, phase 2b study designed to evaluate the effects of the ARI darolutamide (lead-in phase) and darolutamide vs enzalutamide (randomized phase) on physical functioning in men with castration-resistant prostate cancer (CRPC). Only the lead-in phase, in which participants received darolutamide 600mg twice daily, was completed. The TUG and SPPB tests were used to assess physical functioning. The lead-in phase enrolled 30 participants. During 24 weeks of treatment, 8 (32.0%) of 25 evaluable participants exhibited clinically meaningful worsening in TUG from baseline (primary endpoint). At the week 24 visit, 5 (21.7%) of 23 participants had worsening in TUG time, and 8 (33.3%) of 24 participants had worsening in SPPB score. Because only 48% of participants had the same outcome on the TUG and SPPB tests, the study was terminated without initiating the randomized comparison. Most participants showed no clinically meaningful worsening in physical functioning after 24 weeks of darolutamide treatment, but poor agreement between tests was observed. Tools to accurately and consistently measure the impact of ARIs on physical functioning in patients with CRPC are needed.

Prostate Cancer, Pathophysiology and Recent Developments in Management: A Narrative Review.

Prostate cancer is the second most common cancer in men. The different stages of prostate cancer which include localised (low, intermediate, and high risk) disease, locally advanced, non-metastatic castration-resistant prostate cancer (M0 CRPCa), and metastatic disease. The main treatment of locally advanced disease is external beam radiotherapy with hormonal therapy which are associated with good prognosis. Current treatments for M0 CRPCa include androgen deprivation therapy in combination with apalutamide, darolutamide or enzalutamide, all of which are associated with good metastatic-free survival rates in clinical trials. Hormone-naive metastatic prostate cancer comprises the same treatments as M0 CRPCa, whereas further treatment includes docetaxel and abiraterone. Metastatic castration-resistant prostate cancer treatments include sipuleucel-T, radium-223, abiraterone, enzalutamide and cabazitaxel, which aim to slow down the progression of the disease and to prolong life. This article also provides insight into the development of new drugs recently approved for metastatic castration prostate cancer, which include PARP inhibitors and Lutetium-177 which have shown to have significantly good overall survival and to improve radiographic progression-free survival. In addition, new clinical trials are ongoing to test new medications such as cabozantinb and chimeric-antigen receptor T-cell therapy for the treatment of advanced prostate cancer. With the aim to slow down the progression of the disease and to prolong life, new drug developments are underway to hopefully provide a positive impact on overall survival and improve progression-free survival, especially in advanced prostate cancer.

Assessment of the therapeutic efficacy of [177Lu]Lu-PSMA-X compared to taxane chemotherapy in taxane-chemo-naïve patients with metastatic castration-resistant prostate cancer: A systematic review and meta-analysis.

Radioligand therapy (RLT) with 177Lu-labelled prostate specific membrane antigen ([177Lu]Lu-PSMA-X, referring with "PSMA-X" to a generic PSMA chemical compound) inhibitors has emerged as a viable treatment option in metastatic castration resistant prostate cancer patients having previously progressed on taxane and androgen receptor inhibitors. The aim of this study was to perform a systematic review and meta-analysis to assess the therapeutic efficacy of [177Lu]Lu-PSMA-X compared to taxane chemotherapy in taxane-chemo-naïve patients with metastatic castration-resistant prostate cancer. Searches in several bibliographic databases were made using relevant key words, and articles published up to March 2024 were included. The endpoints included prostate specific antigen (PSA) response rate (RR), progression-free survival, and overall survival. Individual patient data were pooled when feasible. PSA50 was defined as the median proportion of patients achieving at least a 50% decline in serum PSA from baseline. A meta-analysis of the PSA50 response rate (proportion meta-analysis) was performed, generating pooled estimates and 95% confidence intervals (95% CI). From the initially selected 8,414 studies published between 2019 and 2023, 24 were included in the [177Lu]Lu-PSMA-X treated group and 17 in the taxane treated group. Our findings show that [177Lu]Lu-PSMA-X RLT yielded comparable PSA50 responses in taxane-naïve patients versus those receiving taxane chemotherapy, despite considerable study heterogeneity. Notably, the taxane-naïve group had more extensive pretreatment. This meta-analysis combines the largest cohorts of taxane-naïve mCRPC patients treated with [177Lu]Lu-PSMA-X RLT and taxane-treated mCRPC. It underscores similar PSA50 response rates in both groups, suggesting a potential role for [177Lu]Lu-PSMA-X RLT in taxane-naïve patients who cannot or choose not to undergo chemotherapy.

The Current Status of Comprehensive Genomic Profiling in the Management of Metastatic Castration-Resistant Prostate Cancer: A Study from a Cooperative Hospital for Cancer Genomic Medicine in Japan.

Several effective treatment modalities against metastatic castration-resistant prostate cancer (mCRPC) are available; however, an unmet clinical need persists for mCRPC treatment because resistance to these therapies is inevitable. This study aimed to evaluate the status of comprehensive genomic profiling (CGP) and its impact on subsequent treatments for patients with mCRPC at our hospital. Between December 2020 and August 2023, we assessed 41 patients with mCRPC who underwent CGP testing at the Nippon Medical School Hospital. The testing comprised FoundationOne® CDx for 30 patients and FoundationOne® Liquid CDx for 11 patients, following the procedures outlined by the Japanese Urological Association. CGP testing was successfully conducted in 40 out of 41 patients (97.6%), which resulted in the identification of 140 actionable genomic alterations. The most common alteration was TP53 in 12 patients (30.0%). Twenty-three patients (57.5%) with druggable gene alterations were identified; 21 were recommended for clinical trials, four for patient-proposed healthcare services, and six for insurance-covered drugs. Consequently, genotype-matched therapy with insurance-covered drugs was administered to five patients (12.5%) with a BRCA2 mutation. Notably, none of the patients underwent clinical or prospective trials based on patient-suggested medical services. Our results offer insights into the real-world application of CGP testing for patients with mCRPC at a cooperative hospital for cancer genomic medicine in Japan. Thus, urologists require a comprehensive understanding of the current status of CGP testing to enhance mCRPC management.

Germline DNA damage repair variants and prognosis of patients with high-risk or metastatic prostate cancer.

Deleterious germline variants in certain DNA repair genes are risk factors for developing aggressive prostate cancer. The objective was to quantify their prognostic impact after prostate cancer diagnosis. Men with prostate cancer, predominantly of European ancestry, were included from four cohorts with long-term follow-up. Pathogenic or likely pathogenic germline variants in 26 DNA repair genes were assessed in relation to metastasis-free survival in high-risk, localized prostate cancer and to overall survival in metastatic castration-sensitive prostate cancer (mCSPC) and metastatic castration-resistant prostate cancer (mCRPC). Among 3,525 patients initially diagnosed with non-metastatic prostate cancer, 2,594 had high-risk localized prostate cancer, 429 mCSPC, and 502 mCRPC at inclusion. BRCA2 variant carriers did not have worse metastasis-free survival in high-risk localized prostate cancer (hazard ratio [HR] 1.01, 95% confidence interval [CI] 0.69, 1.46) or overall survival in mCSPC (HR 0.46, 95% CI 0.14, 1.45) or mCRPC (HR 0.60, 95% CI 0.31, 1.17) compared to non-carriers of DNA repair variants. Among 868 additional patients with de novo metastatic (M1) prostate cancer, BRCA2 variant carriers tended to have worse overall survival (HR 1.59, 95% CI 1.01, 2.51). BRCA2 prognostic associations were not explained by radiation, PARP inhibitor, or platinum therapy. Results for other genes were limited in precision because variants were less common. Among patients with high-risk or metastatic prostate cancer who were initially diagnosed with and treated for non-metastatic tumors, germline DNA repair variants in BRCA2 do not confer a substantially worse prognosis.

MYO6 contributes to tumor progression and enzalutamide resistance in castration-resistant prostate cancer by activating the focal adhesion signaling pathway

BackgroundEnzalutamide (Enz) resistance is a poor prognostic factor for patients with castration-resistant prostate cancer (CRPC), which often involves aberrant expression of the androgen receptor (AR). Myosin VI (MYO6), one member of the myosin family, plays an important role in regulating cell survival and is highly expressed in prostate cancer (PCa). However, whether MYO6 is involved in Enz resistance in CRPC and its mechanism remain unclear.MethodsMultiple open-access databases were utilized to examine the relationship between MYO6 expression and PCa progression, and to screen differentially expressed genes (DEGs) and potential signaling pathways associated with the MYO6-regulated Enz resistance. Both in vitro and in vivo tumorigenesis assays were employed to examine the impact of MYO6 on the growth and Enz resistance of PCa cells. Human PCa tissues and related clinical biochemical data were utilized to identify the role of MYO6 in promoting PCa progression and Enz resistance. The molecular mechanisms underlying the regulation of gene expression, PCa progression, and Enz resistance in CRPC by MYO6 were investigated.ResultsMYO6 expression increases in patients with PCa and is positively correlated with AR expression in PCa cell lines and tissues. Overexpression of AR increases MYO6 expression to promote PCa cell proliferation, migration and invasion, and to inhibit PCa cell apoptosis; whereas knockdown of MYO6 expression reverses these outcomes and enhances Enz function in suppressing the proliferation of the Enz- sensitive and resistant PCa cells both in vitro and in vivo. Mechanistically, AR binds directly to the promoter region (residues − 503 to − 283 base pairs) of MYO6 gene and promotes its transcription. Furthermore, MYO6 activates focal adhesion kinase (FAK) phosphorylation at tyrosine-397 through integrin beta 8 (ITGB8) modulation to promote PCa progression and Enz resistance. Notably, inhibition of FAK activity by Y15, an inhibitor of FAK, can resensitize CRPC cells to Enz treatment in cell lines and mouse xenograft models.ConclusionsMYO6 has pro-tumor and Enz-resistant effects in CRPC, suggesting that targeting MYO6 may be beneficial for ENZ-resistant CRPC therapy through the AR/MYO6/FAK signaling pathway.

PINK1-Mediated Mitochondrial Activity Confers Olaparib Resistance in Prostate Cancer Cells.

Olaparib, a PARP inhibitor, is a targeted therapy used in treating various cancers including castration-resistant prostate cancer (CRPC). Despite its efficacy, resistance to Olaparib remains a significant challenge. Understanding the molecular mechanisms underpinning this resistance is crucial for developing more effective treatment strategies. This study focuses on elucidating the role of mitochondrial alterations and the PINK1 gene in conferring Olaparib resistance in CRPC cells. We investigated the transcriptomic and functional differences in mitochondrial activity between Olaparib-resistant (2B-OlapR, LN-OlapR) and treatment naïve prostate cancer (PCa) cells (C4-2B, LNCaP) in both castration sentitive and resistant settings. Through RNA sequencing and Gene Set Enrichment Analysis (GSEA), we identified significant enrichment of mitochondrial and oxidative phosphorylation-related gene sets in Olaparib Resistant derived cell lines. Resistant lines exhibited enhanced mitochondrial functionality including increased basal and maximal respiration rates, as well as elevated ATP production and spare respiratory capacity compared to parental cells. Subsequent investigations revealed a substantial increase in mitochondrial mass and electron transport chain complex I activity in Olaparib-resistant cells. Furthermore, overexpression of the PINK1 gene was observed in resistant cells, which was correlated with resistance to Olaparib and poor clinical outcomes in prostate cancer patients. Inhibition of PINK1 expression significantly reduced mitochondrial function and mass, impaired cell growth, and decreased resistance to Olaparib. These findings suggest that PINK1 plays a crucial role in modulating mitochondrial dynamics that confer therapeutic resistance, highlighting its potential as a therapeutic target for overcoming Olaparib resistance in PCa.

Predicting Response to [177Lu]Lu-PSMA Therapy in mCRPC Using Machine Learning

Background/Objectives: Radioligandtherapy (RLT) with [177Lu]Lu-PSMA has been newly introduced as a routine treatment for metastatic castration-resistant prostate cancer (mCRPC). However, not all patients can tolerate the entire therapeutic sequence, and in some cases, the treatment may prove ineffective. In real-world conditions, the aim is to distinguish between patients who fully benefit from treatment (those who respond effectively and tolerate the entire therapeutic sequence) and those who do not respond or cannot tolerate the entire sequence. This study explores predictive factors to distinguish between fully beneficial RLT treatment patients (FBTP) and not fully beneficial RLT treatment patients (NFBTP). The objective was to enhance the understanding of predictive factors influencing RLT effectiveness and to highlight the significance of machine learning in optimizing patient selection for treatment planning. Methods: Data from 25 mCRPC patients, categorized as FBTP (11) or NFBTP (14) to RLT, were analyzed. The dataset included clinical, imaging, and biological parameters. Data analysis techniques, including exploratory data analysis and feature engineering, were used to develop machine learning models for predicting patient outcomes. Results: Imaging data analysis revealed statistically significant differences in the renal uptake intensity of Choline between the two groups. A discordance of FDG+ and PSMA− was identified as a potential indicator of NFBTP. The integration of biological data enhanced the model’s predictive capability, achieving an accuracy of 0.92, a sensitivity of 0.96, and a precision of 0.96. Adding blood parameters like neutrophils, leukocytes, and alkaline phosphatase greatly increased prediction accuracy. Conclusions: This study emphasizes the significance of an integrated approach that merges imaging and biological data, thereby augmenting the predictive accuracy of patient outcomes in RLT with [177Lu]Lu-PSMA. In particular, including Choline PET among the imaging parameters provides unique insights into the predictive factors affecting RLT efficacy. This approach not only deepens the understanding of predictive factors but also underscores the utility of machine learning in refining the patient selection process for optimized treatment planning.