Synthesis and new DNA targeting activity of 6- and 7-tert-butylfascaplysins.

Fascaplysin is a red cytotoxic pigment with anticancer properties isolated from the marine sponge Fascaplysinopsis sp. Recently, structure-activity relationship analysis reported by our group suggested that selective cytotoxicity of fascaplysin derivatives towards tumor cells negatively correlates with their ability to intercalate into DNA. To validate this hypothesis, we synthesized 6- and 7-tert-butylfascaplysins which reveal mitigated DNA-intercalating properties. These derivatives were found to be strongly cytotoxic to drug-resistant human prostate cancer cells, albeit did not demonstrate improved selectivity towards cancer cells when compared to fascaplysin. At the same time, kinome analysis suggested an activation of CHK1/ATR axis in cancer cells shortly after the drug exposure. Further experiments revealed induction of replication stress that is eventually converted to the toxic DNA double-strand breaks, resulting in caspase-independent apoptosis-like cell death. Our observations highlight new DNA-targeting effect of some fascaplysin derivatives and indicate more complex structure-activity relationships within the fascaplysin family, suggesting that cytotoxicity and selectivity of these alkaloids are influenced by multiple factors. Furthermore, combination with clinically-approved inhibitors of ATR/CHK1 as well as testing in tumors particularly sensitive to the DNA damage should be considered in further studies.

A Combined Cyto- and Histopathological Diagnostic Approach Reduces Time to Diagnosis and Time to Therapy in First Manifestation of Metastatic Spinal Disease: A Cohort Study.

Malignant spinal lesions (MSLs) are frequently the first manifestation of malignant disease. Spinal care, diagnostic evaluation, and the initiation of systemic therapy are crucial for outcomes in patients (pts) with advanced cancer. However, histopathology (HP) may be time consuming. The additional evaluation of spinal lesions using cytopathology (CP) has the potential to reduce the time to diagnosis (TTD) and time to therapy (TTT). CP and HP specimens from spinal lesions were evaluated in parallel in 61 pts (CP/HP group). Furthermore, 139 pts in whom only HP was performed were analyzed (HP group). We analyzed the TTD of CP and HP within the CP/HP group. Furthermore, we compared the TTD and TTT between the groups. The mean TTD in CP was 1.7 ± 1.7 days (d) and 8.4 ± 3.6 d in HP (p < 0.001). In 13 pts in the CP/HP group (24.1%), specific therapy was initiated based on the CP findings in combination with imaging and biomarker results before completion of HP. The mean TTT in the CP/HP group was 21.0 ± 15.8 d and was significantly shorter compared to the HP group (28.6 ± 23.3 d) (p = 0.034). Concurrent CP for MSLs significantly reduces the TTD and TTT. As a result, incorporating concurrent CP for analyzing spinal lesions suspected of malignancy might have the potential to enhance pts' quality of life and prognosis in advanced cancer. Therefore, we recommend implementing CP as a standard procedure for the evaluation of MSLs.

Limited prognostic role of routine serum markers (AP, CEA, LDH and NSE) in oligorecurrent prostate cancer patients undergoing PSMA-radioguided surgery.

INTRODUCTION: We evaluated the prognostic role of pre-salvage prostate-specific membrane antigen-radioguided surgery (PSMA-RGS) serum levels of alkaline phosphatase (AP), carcinoembryonic antigen (CEA), lactate dehydrogenase (LDH), and neuron-specific enolase (NSE). MATERIALS AND METHODS: Patients who consecutively underwent PSMA-RGS for prostate cancer (PCa) oligorecurrence between January 2019 and January 2022 were selected. Biomarkers were assessed one day before surgery. Cox regression and logistic regression models tested the relationship between biochemical recurrence-free survival (BFS), 6- and 12-month biochemical recurrence (BCR), and several independent variables, including biomarkers. RESULTS: 153 consecutive patients were analyzed. In the univariable Cox regression analysis, none of the biomarkers achieved predictor status (AP: hazard ratio [HR] = 1.03, 95% CI 0.99, 1.01; p = 0.19; CEA: HR = 1.73, 95% CI 0.94, 1.21; p = 0.34; LDH: HR = 1.01, 95% CI 1.00, 1.01; p = 0.05; NSE: HR = 1.02, 95% CI 0.98, 1.06; p = 0.39). The only independent predictor of BFS was the number of positive lesions on PSMA PET (HR = 1.17, 95% CI 1.02, 1.30; p = 0.03). The number of positive lesions was confirmed as independent predictor for BCR within 6 and 12 months (BCR < 6 months: odds ratio [OR] = 1.1, 95% CI 1.0, 1.3; p = 0.04; BCR < 12 months: OR = 1.1, 95% CI 1.0, 1.3; p = 0.04). CONCLUSION: The assessment of AP, CEA, LDH, and NSE before salvage PSMA-RGS showed no prognostic impact. Further studies are needed to identify possible predictors that will optimize patient selection for salvage PSMA-RGS.

[Molecular testing of prostate cancer: timing, methods and consequences]. / Molekulare Testung des Prostatakarzinoms: wann, wie und mit welcher Konsequenz?

Metastatic prostate cancer is a heterogeneous disease. To date, however, treatment decisions are often based on the extent and symptom burden of the tumour, concomitant diseases, and the patient's wishes. Molecular pathology aspects are rarely taken into account. Declining costs and the increasing use of next-generation sequencing (NGS) have led to an increase in molecular testing and a better understanding of the significance of molecular alterations for the development and spread of prostate cancer. More consistent germline testing reveals hereditary predispositions. Following the approval of olaparib for the treatment of BRCA1/2 mutated, castration-resistant prostate cancer, further targeted therapeutic approaches are currently under development. In our review article, we provide an overview of current molecular testing in prostate cancer and discuss possible consequences.

[Advanced renal cell carcinoma - an overview of current systemic therapy]. / Das fortgeschrittene Nierenzellkarzinom ­ Aktuelle Systemtherapie im Überblick.

Renal cell carcinoma (RCC) is one of the more common tumor diseases in older adults. The only curative treatment method is surgical resection in the localized stage. Based on current study data, drug (combination) therapy in the metastatic stage is the most effective treatment option for non-resectable/metastatic RCC (mRCC). Immuno-oncological combinations of 2 Checkpoint-Inhibitors (CPI) or CPIs and Tyrosine kinase inhibitors (TKI) are now standard in the first-line treatment of metastatic RCC. Since the results of foundational combination therapy studies are not fully comparable due to different study design and patient populations, additional clinical and patient-related criteria are required when making individual treatment decisions. The systemic therapy of advanced RCC is therefore based on tumor extent, treatment pressure, concomitant diseases, and personal circumstances. A decision on first-line therapy should be made individually as part of a "shared decision" with the patient. The selection of a second-line systemic therapy is based on individual criteria; the data available for a well-founded classification of a possible therapy sequence after progression to first-line therapy is sparse. Further investigations to optimize systemic therapy (expansion of combination therapy to triple combination of CPI+CPI+TKI) or evaluation of therapy in other histological subtypes of renal cell carcinoma are the subject of ongoing clinical studies.

[Androgen deprivation therapy and cardiovascular morbidity in prostate cancer: a narrative review]. / Androgendeprivationstherapie und kardiovaskuläre Morbidität beim Prostatakarzinom: ein narratives Review.

Prostate cancer is the most common malignancy in men, mostly affecting older men who harbor an increased prevalence of cardiovascular disease and metabolic syndrome. Androgen deprivation therapy (ADT), the standard therapy for various stages of prostate cancer, further increases the risk for cardiovascular disease and for metabolic syndrome. Therefore, screening for cardiovascular risk factors should be performed prior to the initiation of ADT, and, if necessary, cardiological evaluation and interdisciplinary management should be provided during and after completion of ADT. Moreover, the use of a gonadotropin-releasing hormone (GnRH) antagonist may help reduce cardiovascular risk in patients with cardiovascular disease.

PSMA PET-directed surgical metastasis-directed therapy in metachronous prostate cancer.

We present the case of a patient who underwent an open radical prostatectomy with pelvic lymph node dissection (Gleason 4+3, pT3a pN1 R0) in March 2017. In November 2020, prostate-specific membrane antigen (PSMA)-radioguided salvage lymph node dissection was planned due to a single left para-rectal lymph node at a [68Ga] Ga-PSMA-I&T PET. In January 2022, the [68Ga] Ga-PSMA-I&T PET showed an isolated liver lesion. Biopsy confirmed prostate adenocarcinoma. A liver segmentectomy was performed. A complete biochemical response was reported until the last follow-up (December 2022). Prostate-specific membrane antigen positron emission tomography (PSMA PET)-directed metastasis-directed therapy may be an effective treatment in selected cases, allowing a benefit in the oncological outcome.

Preclinical Comparison of the 64Cu- and 68Ga-Labeled GRPR-Targeted Compounds RM2 and AMTG, as Well as First-in-Humans [68Ga]Ga-AMTG PET/CT.

Despite the recent success of prostate-specific membrane antigen (PSMA)-targeted compounds for theranostic use in prostate cancer (PCa), alternative options for the detection and treatment of PSMA-negative lesions are needed. We have recently developed a novel gastrin-releasing peptide receptor (GRPR) ligand with improved metabolic stability, which might improve diagnostic and therapeutic efficacy and could be valuable for PSMA-negative PCa patients. Our aim was to examine its suitability for theranostic use. We performed a comparative preclinical study on [64Cu]Cu-/[68Ga]Ga-AMTG ([64Cu]Cu-/[68Ga]Ga-α-Me-l-Trp8-RM2) using [64Cu]Cu-/[68Ga]Ga-RM2 ([64Cu]Cu-/[68Ga]Ga-DOTA-Pip5-Phe6-Gln7-Trp8-Ala9-Val10-Gly11-His12-Sta13-Leu14-NH2) as a reference compound and investigated [68Ga]Ga-AMTG in a proof-of-concept study in a PCa patient. Methods: Peptides were labeled with 64Cu (80 °C, 1.0 M NaOAc, pH 5.50) and 68Ga (90 °C, 0.25 M NaOAc, pH 4.50). GRPR affinity (half-maximal inhibitory concentration, room temperature, 2 h) and GRPR-mediated internalization (37 °C, 60 min) were examined on PC-3 cells. Biodistribution studies were performed at 1 h after injection in PC-3 tumor-bearing mice. For a first-in-humans application, 173 MBq of [68Ga]Ga-AMTG were administered intravenously and whole-body PET/CT scans were acquired at 75 min after injection. Results: 64Cu- and 68Ga-labeling proceeded almost quantitatively (>98%). All compounds revealed similarly high GRPR affinity (half-maximal inhibitory concentration, 1.5-4.0 nM) and high receptor-bound fractions (79%-84% of cell-associated activity). In vivo, high activity levels (percentage injected dose per gram) were found in the PC-3 tumor (14.1-15.1 %ID/g) and the pancreas (12.6-30.7 %ID/g), whereas further off-target accumulation was low at 1 h after injection, except for elevated liver uptake observed for both 64Cu-labeled compounds. Overall biodistribution profiles and tumor-to-background ratios were comparable but slightly enhanced for the 68Ga-labeled analogs in most organs. [68Ga]Ga-AMTG confirmed the favorable pharmacokinetics-as evident from preclinical studies-in a patient with metastasized castration-resistant PCa showing intense uptake in several lesions. Conclusion: AMTG is eligible for theranostic use, as labeling with 64Cu and 68Ga, as well as 177Lu (known from previous study), does not have a negative influence on its favorable biodistribution pattern. For this reason, further clinical evaluation is warranted.

[Metastatic castration-resistant prostate cancer-emerging trends in therapy]. / Metastasiertes kastrationsresistentes Prostatakarzinom ­ Was kommt neues.

BACKGROUND: An increasing understanding of the cellular processes involved in growth, metastasis and development of resistance enable the development of new treatment strategies for advanced prostate cancer. OBJECTIVES: Using selected examples, the aim of this report is to present current developments to the reader and to give an outlook on possible upcoming changes in the treatment of advanced prostate cancer. MATERIALS AND METHODS: Narrative report based on expert consensus, supported by a literature search in PubMed (MEDLINE) and the abstract databases of the American Society of Clinical Oncology (ASCO) and European Society of Medical Oncology (ESMO). Examples were selected to illustrate current developments without claiming completeness. RESULTS: The androgen receptor (AR) signal transduction pathway remains a focus of scientific interest. Androgen synthesis inhibitors and AR degraders are promising new approaches to overcome resistance mediated by AR mutations or splice variants. Inhibition of key switch sites of alternative signaling pathways such as AKT or CDK4/6 provide additional treatment options, including combinational strategies through a tight linkage with the AR signaling pathway. A better understanding of tumor microenvironment and immune response is required for novel immunotherapeutic strategies using bispecific T­cell engagers (BiTEs) and chimeric antigen receptor (CAR) T cells. CONCLUSION: New treatment strategies give hope that we will be able to intervene even more effectively in the course of disease of advanced prostate cancer in the future. However, a major challenge, especially for the implementation of targeted treatment approaches, is likely to be the heterogeneity of tumor progression not only inter- but also intrapersonally.

Biweekly vs Triweekly Cabazitaxel in Older Patients With Metastatic Castration-Resistant Prostate Cancer: The CABASTY Phase 3 Randomized Clinical Trial.

Importance: Many patients 65 years or older with metastatic castration-resistant prostate cancer (mCRPC) are denied taxane chemotherapy because this treatment is considered unsuitable. Objective: To determine whether biweekly cabazitaxel (CBZ), 16 mg/m2 (biweekly CBZ16), plus prophylactic granulocyte colony-stimulating factor (G-CSF) at each cycle reduces the risk of grade 3 or higher neutropenia and/or neutropenic complications (eg, febrile neutropenia, neutropenic infection, or sepsis) compared with triweekly CBZ, 25 mg/m2 (triweekly CBZ25), plus G-CSF (standard regimen). Design, Setting, and Participants: A total of 196 patients 65 years or older with progressive mCRPC were enrolled in this prospective phase 3 randomized clinical trial conducted in France (18 centers) and Germany (7 centers) between May 5, 2017, and January 7, 2021. All patients had received docetaxel and at least 1 novel androgen receptor-targeted agent. Interventions: Patients were randomly assigned 1:1 to receive biweekly CBZ16 plus G-CSF and daily prednisolone (experimental group) or triweekly CBZ25 plus G-CSF and daily prednisolone (control group). Main Outcome and Measures: The primary end point was the occurrence of grade 3 or higher neutropenia measured at nadir and/or neutropenic complications. Results: Among 196 patients (97 in the triweekly CBZ25 group and 99 in the biweekly CBZ16 group), the median (IQR) age was 74.6 (70.4-79.3) years, and 181 (92.3%) had an Eastern Cooperative Oncology Group performance status of 0 or 1. The median (IQR) follow-up duration was 31.3 (22.5-37.5) months. Relative dose intensities were comparable between groups (median [IQR], 92.7% [83.7%-98.9%] in the triweekly CBZ25 group vs 92.8% [87.0%-98.9%] in the biweekly CBZ16 group). The rate of grade 3 or higher neutropenia and/or neutropenic complications was significantly higher with triweekly CBZ25 vs biweekly CBZ16 (60 of 96 [62.5%] vs 5 of 98 [5.1%]; odds ratio, 0.03; 95% CI, 0.01-0.08; P < .001). Grade 3 or higher adverse events were more common with triweekly CBZ25 (70 of 96 [72.9%]) vs biweekly CBZ16 (55 of 98 [56.1%]). One patient (triweekly CBZ25 group) died of a neutropenic complication. Conclusions and Relevance: In this randomized clinical trial, compared with the standard regimen, biweekly CBZ16 plus G-CSF significantly reduced by 12-fold the occurrence of grade 3 or higher neutropenia and/or neutropenic complications, with comparable clinical outcomes. The findings suggest that biweekly CBZ16 regimen should be offered to patients 65 years or older with mCRPC for whom the standard regimen is unsuitable. Trial Registration: ClinicalTrials.gov Identifier: NCT02961257.

Rhizochalinin Exhibits Anticancer Activity and Synergizes with EGFR Inhibitors in Glioblastoma In Vitro Models.

Rhizochalinin (Rhiz) is a recently discovered cytotoxic sphingolipid synthesized from the marine natural compound rhizochalin. Previously, Rhiz demonstrated high in vitro and in vivo efficacy in various cancer models. Here, we report Rhiz to be highly active in human glioblastoma cell lines as well as in patient-derived glioma-stem like neurosphere models. Rhiz counteracted glioblastoma cell proliferation by inducing apoptosis, G2/M-phase cell cycle arrest, and inhibition of autophagy. Proteomic profiling followed by bioinformatic analysis suggested suppression of the Akt pathway as one of the major biological effects of Rhiz. Suppression of Akt as well as IGF-1R and MEK1/2 kinase was confirmed in Rhiz-treated GBM cells. In addition, Rhiz pretreatment resulted in a more pronounced inhibitory effect of γ-irradiation on the growth of patient-derived glioma-spheres, an effect to which the Akt inhibition may also contribute decisively. In contrast, EGFR upregulation, observed in all GBM neurospheres under Rhiz treatment, was postulated to be a possible sign of incipient resistance. In line with this, combinational therapy with EGFR-targeted tyrosine kinase inhibitors synergistically increased the efficacy of Rhiz resulting in dramatic inhibition of GBM cell viability as well as a significant reduction of neurosphere size in the case of combination with lapatinib. Preliminary in vitro data generated using a parallel artificial membrane permeability (PAMPA) assay suggested that Rhiz cannot cross the blood brain barrier and therefore alternative drug delivery methods should be used in the further in vivo studies. In conclusion, Rhiz is a promising new candidate for the treatment of human glioblastoma, which should be further developed in combination with EGFR inhibitors.

A New Mild Method for Synthesis of Marine Alkaloid Fascaplysin and Its Therapeutically Promising Derivatives.

Fascaplysin is a marine alkaloid which is considered to be a lead drug candidate due to its diverse and potent biological activity. As an anticancer agent, fascaplysin holds a great potential due to the multiple targets affected by this alkaloid in cancer cells, including inhibition of cyclin-dependent kinase 4 (CDK4) and induction of intrinsic apoptosis. At the same time, the studies on structural optimization are hampered by its rather high toxicity, mainly caused by DNA intercalation. In addition, the number of methods for the syntheses of its derivatives is limited. In the current study, we report a new two-step method of synthesis of fascaplysin derivatives based on low temperature UV quaternization for the synthesis of thermolabile 9-benzyloxyfascaplysin and 6-tert-butylfascaplysin. 9-Benzyloxyfascaplysin was used as the starting compound to obtain 9-hydroxyfascaplysin. However, the latter was found to be chemically highly unstable. 6-tert-Butylfascaplysin revealed a significant decrease in DNA intercalation when compared to fascaplysin, while cytotoxicity was only slightly reduced. Therefore, the impact of DNA intercalation for the cytotoxic effects of fascaplysin and its derivatives needs to be questioned.

Enfortumab Vedotin in Metastatic Urothelial Carcinoma: Survival and Safety in a European Multicenter Real-world Patient Cohort.

Background: Treatment options for patients with urothelial cancer (UC) refractory to platinum and immunotherapy are limited and survival is short. Enfortumab vedotin (EV) is a monoclonal anti-NECTIN4 antibody conjugated to monomethyl auristatin. It was recently approved because of superior survival in comparison to standard-of-care (SOC) chemotherapy. Real-world patients, however, often have worse characteristics than patients included in clinical trials. Objective: To analyze the efficacy and safety of EV in a cohort of real-world patients. Design setting and participants: Retrospective data were collected from 23 hospitals and private practices for patients with metastatic and previously treated UC who received EV either when reimbursed by their insurance company before European Medicines Agency (EMA) approval, within a compassionate use program, or as SOC treatment after EMA approval. Imaging and therapy management were in accordance with local standards. Outcome measurements and statistical analysis: Adverse events (AEs) were reported according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 criteria. Objective responses were evaluated according to Response Evaluation Criteria in Solid Tumors version 1.1. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Results and limitations: The median age for the 125 eligible patients was 66 yr (range 31-89). The Eastern Cooperative Oncology Group performance status (ECOG PS) was 0-1 for 76.0%, 2-4 for 13.6%, and unknown for 10.4% of patients. EV was administered in the fourth or later line for 44.8% of patients. The overall response rate was 41.6% (partial response 39.2%, complete response 2.4%). Median OS was 10.0 months (mo) (95% confidence interval 7.20-12.80) and median PFS was 5.0 mo (95% confidence interval 4.34-5.67). For patients with ECOG PS of 0-1, median OS was 14 mo. Any-grade AEs were observed in 67.2% and CTCAE grade ≥3 AEs in 30.4%. The most common AEs were peripheral sensory neuropathy and skin toxicity. Three fatal events (pneumonia, pneumonitis) occurred. Limitations include the retrospective design and short follow-up. Conclusions: Administration of EV for real-world patients was feasible with an acceptable toxicity profile. No new safety signals were reported. Antitumor activity in our cohort was comparable to data previously reported for trials. In summary, our results support the use of EV in patients with metastatic UC. Patient summary: Enfortumab vedotin is a medication that improved the survival of patients with bladder cancer in comparison to standard chemotherapy in clinical trials. However, patients included in clinical trials are highly selected and results for toxicities and improvements in survival do not always transfer to the real-world setting. We analyzed data for 125 patients who were treated with enfortumab vedotin. Our results are comparable to the outcomes from clinical trials regarding the safety and efficacy of this treatment.

[Sequential therapy of advanced bladder cancer after prior perioperative systemic treatment : Recommendations from the Interdisciplinary Bladder Carcinoma Working Group (IABC) of the DKG e. V.] / Sequenztherapie des fortgeschrittenen Urothelkarzinoms der Harnblase nach vorheriger perioperativer Systembehandlung : Empfehlungen aus der Interdisziplinären Arbeitsgruppe BlasenCarcinom (IABC) der Deutschen Krebsgesellschaft e. V. (DKG).

Guidelines can only give treatment recommendations for defined patient groups if high quality and meaningful evidence is available. However, patients included in clinical trials for the treatment of metastatic and/or locally advanced bladder cancer (mUC) are generally not representative for the spectrum of patients encountered in daily clinical practice. In particular, patients with different systemic pretreatments, variable prestudy responses or variable time to tumor progression are not sufficiently considered in trials and guideline recommendations. Accordingly, recommendations for the treatment of mUC patients with previous perioperative systemic therapy are lacking. To provide some guidance for daily uro-oncological practice despite the limited evidence, we sought to develop expert opinion-based treatment recommendations. These recommendations focus on palliative first-line therapy of mUC. Both perioperative pretreatment with classical cisplatin-based systemic therapy and/or immunotherapy, as well as the time to tumor recurrence have been considered.

New Bioactive ß-Resorcylic Acid Derivatives from the Alga-Derived Fungus Penicillium antarcticum KMM 4685.

Five new ß-resorcylic acid derivatives, 14-hydroxyasperentin B (1), ß-resoantarctines A-C (3, 5, 6) and 8-dehydro-ß-resoantarctine A (4), together with known 14-hydroxyasperentin (5'-hydroxyasperentin) (2), were isolated from the ethyl acetate extract of the fungus Penicillium antarcticum KMM 4685 associated with the brown alga Sargassum miyabei. The structures of the compounds were elucidated by spectroscopic analyses and modified Mosher's method, and the biogenetic pathways for compounds 3-6 were proposed. For the very first time, the relative configuration of the C-14 center of a known compound 2 was assigned via analyses of magnitudes of the vicinal coupling constants. The new metabolites 3-6 were biogenically related to resorcylic acid lactones (RALs); however, they did not possess lactonized macrolide elements in their structures. Compounds 3, 4 and 5 exhibited moderate cytotoxic activity in LNCaP, DU145 and 22Rv1 human prostate cancer cells. Moreover, these metabolites could inhibit the activity of p-glycoprotein at their noncytotoxic concentrations and consequently synergize with docetaxel in p-glycoprotein-overexpressing drug-resistant cancer cells.

Randomized Phase II Cabazitaxel Dose Individualization and Neutropenia Prevention Trial in Patients with Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: There is ongoing controversy about the recommended dose of cabazitaxel in patients with metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: This multicenter phase II open-label, randomized, parallel-group study compared 3-weekly cabazitaxel at 25 mg/m2 (conventional arm A) with cabazitaxel therapeutic drug monitoring (experimental arm B) in mCRPC. The primary objective was to improve the clinical feasibility rate (CFR), defined as the absence of grade 4 neutropenia or thrombocytopenia, any thrombocytopenia with bleeding, febrile neutropenia, severe nonhematologic toxicity, withdrawal for cabazitaxel-related toxicity, or death. A total of 60 patients had to be randomized to detect a difference in CFR of 35% (power 80%, two-sided alpha 10%). RESULTS: A total of 40 patients were randomized to arm A and 33 patients to arm B. CFR was 69.4% in arm A and 64.3% in arm B (P = 0.79). Week-12 PSA response was 38.5% in both arms. A radiological response by RECIST v.1.1 was seen in 3 (9.7%) patients in arm A versus 6 (23.1%) patients in arm B (P = 0.28), disease progression was higher in arm A compared with arm B (61.3% vs. 30.8%, P = 0.05). Median progression-free survival was longer in arm B compared with arm A (9.5 vs. 4.4 months; HR = 0.46; P = 0.005). Median overall survival was higher in arm B compared with arm A (16.2 vs. 7.3 months; HR = 0.33; P < 0.0001). CONCLUSIONS: Pharmacokinetic-guided dosing of cabazitaxel in patients with mCRPC is feasible and improves clinical outcome due to individual dose escalations in 55% of patients.

New Marine Fungal Deoxy-14,15-Dehydroisoaustamide Resensitizes Prostate Cancer Cells to Enzalutamide.

Marine fungi serve as a valuable source for new bioactive molecules bearing various biological activities. In this study, we report on the isolation of a new indole diketopiperazine alkaloid deoxy-14,15-dehydroisoaustamide (1) from the marine-derived fungus Penicillium dimorphosporum KMM 4689 associated with a soft coral. The structure of this metabolite, including its absolute configuration, was determined by HR-MS, 1D and 2D NMR as well as CD data. Compound 1 is a very first deoxyisoaustamide alkaloid possessing two double bonds in the proline ring. The isolated compound was noncytotoxic to a panel of human normal and cancer cell lines up to 100 µM. At the same time, compound 1 resensitized prostate cancer 22Rv1 cells to androgen receptor (AR) blocker enzalutamide. The mechanism of this phenomenon was identified as specific drug-induced degradation of androgen receptor transcription variant V7 (AR-V7), which also resulted in general suppression of AR signaling. Our data suggest that the isolated alkaloid is a promising candidate for combinational therapy of castration resistant prostate cancer, including drug-resistant subtypes.

Preclinical patient-derived modeling of castration-resistant prostate cancer facilitates individualized assessment of homologous recombination repair deficient disease.

The use of mutation analysis of homologous recombination repair (HRR) genes to estimate PARP-inhibition response may miss a larger proportion of responding patients. Here, we provide preclinical models for castration-resistant prostate cancer (CRPC) that can be used to functionally predict HRR defects. In vitro, CRPC LNCaP sublines revealed an HRR defect and enhanced sensitivity to olaparib and cisplatin due to impaired RAD51 expression and recruitment. Ex vivo-induced castration-resistant tumor slice cultures or tumor slice cultures derived directly from CRPC patients showed increased olaparib- or cisplatin-associated enhancement of residual radiation-induced γH2AX/53BP1 foci. We established patient-derived tumor organoids (PDOs) from CRPC patients. These PDOs are morphologically similar to their primary tumors and genetically clustered with prostate cancer but not with normal prostate or other tumor entities. Using these PDOs, we functionally confirmed the enhanced sensitivity of CRPC patients to olaparib and cisplatin. Moreover, olaparib but not cisplatin significantly decreased the migration rate in CRPC cells. Collectively, we present robust patient-derived preclinical models for CRPC that recapitulate the features of their primary tumors and enable individualized drug screening, allowing translation of treatment sensitivities into tailored clinical therapy recommendations.

Experimental in vitro, ex vivo and in vivo models in prostate cancer research.

Androgen deprivation therapy has a central role in the treatment of advanced prostate cancer, often causing initial tumour remission before increasing independence from signal transduction mechanisms of the androgen receptor and then eventual disease progression. Novel treatment approaches are urgently needed, but only a fraction of promising drug candidates from the laboratory will eventually reach clinical approval, highlighting the demand for critical assessment of current preclinical models. Such models include standard, genetically modified and patient-derived cell lines, spheroid and organoid culture models, scaffold and hydrogel cultures, tissue slices, tumour xenograft models, patient-derived xenograft and circulating tumour cell eXplant models as well as transgenic and knockout mouse models. These models need to account for inter-patient and intra-patient heterogeneity, the acquisition of primary or secondary resistance, the interaction of tumour cells with their microenvironment, which make crucial contributions to tumour progression and resistance, as well as the effects of the 3D tissue network on drug penetration, bioavailability and efficacy.

Anticancer Activity of the Marine Triterpene Glycoside Cucumarioside A2-2 in Human Prostate Cancer Cells.

Despite recent advances in the treatment of metastatic castration-resistant prostate cancer (CRPC), treatment is inevitably hampered by the development of drug resistance. Thus, new drugs are urgently needed. We investigated the efficacy, toxicity, and mechanism of action of the marine triterpene glycoside cucumarioside A2-2 (CA2-2) using an in vitro CRPC model. CA2-2 induced a G2/M-phase cell cycle arrest in human prostate cancer PC-3 cells and caspase-dependent apoptosis executed via an intrinsic pathway. Additionally, the drug inhibited the formation and growth of CRPC cell colonies at low micromolar concentrations. A global proteome analysis performed using the 2D-PAGE technique, followed by MALDI-MS and bioinformatical evaluation, revealed alterations in the proteins involved in cellular processes such as metastatic potential, invasion, and apoptosis. Among others, the regulation of keratin 81, CrkII, IL-1ß, and cathepsin B could be identified by our proteomics approach. The effects were validated on the protein level by a 2D Western blotting analysis. Our results demonstrate the promising anticancer activity of CA2-2 in a prostate cancer model and provide insights on the underlying mode of action.