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.

[Androgen deprivation therapy and cardiovascular morbidity in prostate cancer: a narrative 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.

[Advanced renal cell carcinoma - an overview of current systemic therapy]

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.

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-1β, 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.

[Metastatic castration-resistant prostate cancer-emerging trends in therapy]

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 T‑cell 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.

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.

[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.]

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.

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.

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.

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.

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.

Abstract 1447: Retinoic acid-induced 2 driven polymerization of c-terminal binding proteins sustains epithelial differentiation in castration-resistant prostate cancer

Previously, we found that increased Retinoic acid-induced 2 (RAI2) protein concentration in primary tumors predicts early biochemical relapse of prostate cancer patients and described a co-repressor function of RAI2 related to androgen receptor activity (1). The presence of a non-canonical tandem ALDLS motif on RAI2 protein prompted the present investigation on a possible role of a dual interaction of RAI2 with C-terminal binding proteins (CtBPs) in relation to prostate cancer progression.

We analyzed RAI2 gene expression as well as CtBP1 protein localization and constitution in circulating tumors cells (CTCs) isolated from metastatic prostate cancer patients by semi-quantitative PCR analysis and immune-fluorescence staining. We employed an integrated structural biology approach combining biophysical techniques like isothermal calorimetry, circular dichroism, size exclusion chromatography with high-resolution structural biology techniques including X-ray crystallography and single particle cryo-electron microscopy. We established RAI2-depleted VCaP cells and used this model for validation of the obtained results.

RAI2 gene expression is significantly increased in CTCs isolated from patients with castration-resistant disease in comparison to CTCs isolated from patients with hormone-sensitive, aggressive or neuroendocrine variant prostate cancer. We detected CtBP1 protein foci in the nuclei of individual CTCs. We show that RAI2 induces CtBP polymerization. Using single particle cryo-electron microscopy, we obtained crucial insights into the structural organization of this filament. RAI2 inactivation in VCaP cells caused a significant reduction of both CtBP proteins, which is accompanied by the disappearance of CtBP protein aggregates in nuclei. In addition, we observed the induction of neuroendocrine features, marked by the induction of Synaptophysin and Chromogranin A, a higher nucleus to cytoplasm ratio and smaller cell size of RAI2-depleted cells.

In summary, we report tandem motifs-induced polymerization of CtBP’s for the first time. We found that elevated RAI2 gene expression is a characteristic of castration-resistant prostate cancer. Because RAI2 depletion resulted in loss of CtBP aggregates and the induction of neuroendocrine traits, we conclude that RAI2-driven CtBP polymerization sustains epithelial differentiation in castration-resistant prostate cancer. These findings holds potential for the diagnosis of castration-resistant disease and inhibiting the progression from castration-resistant to neuroendocrine prostate cancer.

1. Besler K, Weglarz A, Keller L, von Amsberg G, Bednarz-Knoll N, Offermann A, et al. Expression Patterns and Corepressor Function of Retinoic Acid-induced 2 in Prostate Cancer. Clin Chem 2022;68:973-83

Citation Format: Stefan Werner, Nishit Goradia, Edukondalu Mullapudi, Lina Merkens, Sarah Greimeier, Aleksandra Węglarz, Gunhild von Amsberg, Harriet Wikman, Klaus Pantel, Matthias Wilmanns. Retinoic acid-induced 2 driven polymerization of c-terminal binding proteins sustains epithelial differentiation in castration-resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1447.

Abstract 3370: Liquid biopsy approaches to determine tumor cell heterogeneity in advanced prostate cancer

Aggressive variants of prostate cancer (AVPC) emerge from prostate adenocarcinoma following enduring therapeutic pressure. They grow independent of the androgen receptor, progress rapidly and can show traits of neuroendocrine (NE) differentiation. As progression to AVPC is not well detected by prostate specific antigen monitoring, new biomarkers are urgently needed. The aim of this study is to evaluate the detection of circulating tumor cells (CTCs) in combination with gene expression analysis of NE genes to identify AVPC patients with neuroendocrine traits.

Blood samples were collected from patients suffering from AVPC (n=78, including 25 patients with histological evidence of NEPC) as well as from patients with hormone-sensitive prostate cancer (HSPC) as controls (n=12) at the University Medical Center Hamburg-Eppendorf. CTC counts were determined by CellSearch analysis. In parallel, CTCs were immuno-magnetically enriched using the AdnaTest and bulk gene expression of prostate-specific and NE genes was analyzed by semi-quantitative PCR. From a subset of patients, CTCs were additionally enriched by Parsortix to compare gene expression of CTCs with EpCAM-based or size-based CTC enrichment.

Using CellSearch analysis, CTCs were found in 88.9 % of AVPC patients. CTC counts ranged between 0 – 20,000 CTCs/7.5 ml of blood with a median of 32 CTCs/7.5 ml. Similarly, 81.8 % of NEPC patients were positive for CTCs with a median count of 35 CTCs/7.5 ml (range 0-13,000). In contrast, CTCs were found in only 50 % of HSPC patients at lower concentrations (median count of 0.5 CTCs/7.5 ml, range 0-34). CTC counts were significantly elevated in AVPC and NEPC patients compared to HSPC (p = 0.002, p = 0.012), but no significant differences were found between AVPC and NEPC samples.In 93.8 % of AVPC samples, CTCs expressed prostate-specific genes such as KLK3 or PSMA. At least one of the NE transcripts was detected in 37.5 % of AVPC patients. In CTCs from NEPC patients, the positivity for prostate markers was significantly reduced to 66.6 % (p = 0.01) and the positivity for NE markers was increased to 61.1 %. A random Forrest model trained on all analyzed transcripts allowed for a distinction of HSPC and NEPC with an AUC of 79.5 %. Comparison of CTC enrichment strategies in a subset of 13 patients showed similar NE marker detection by size-based enrichment (53.8 % NE-positive) compared to the AdnaTest (61.5 % NE-positive).

AVPC and NEPC patients show a high CTC burden that will allow subsequent molecular analyses, and CTC counts allowed a distinction between blood samples from HSPC and NEPC patients. Gene expression analysis revealed a high degree of inter-patient heterogeneity for neuroendocrine-specific transcripts with a reduction of prostate markers in NEPC patients. Future molecular characterization and longitudinal monitoring of CTCs will shed more light on the evolution of AVPC and NEPC.

Citation Format: Lina Merkens, Sarah Greimeier, Sabine Riethdorf, Klaus Pantel, Gunhild von Amsberg, Stefan Werner. Liquid biopsy approaches to determine tumor cell heterogeneity in advanced prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3370.

Randomized phase 2 Cabazitaxel dose individualization and Neutropenia prevention Trial (CAINTA) 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).

EXPERIMENTAL DESIGN

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 (TDM) (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 non-hematological toxicity, withdrawal for cabazitaxel-related toxicity or death. 60 patients had to be randomized to detect a difference in CFR of 35% (power 80%, 2-sided alpha 10%).

RESULTS

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 to Arm B (61.3% versus 30.8%, P = 0.05). Median PFS was longer in Arm B compared to Arm A (9.5 versus 4.4 months, HR = 0.46, P = 0.005). Median OS was higher in Arm B compared to Arm A (16.2 versus 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.

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.

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.

Meroantarctines A-C, Meroterpenoids with Rearranged Skeletons from the Alga-Derived Fungus Penicillium antarcticum KMM 4685 with Potent p-Glycoprotein Inhibitory Activity

New meroterpenoids, meroantarctines A-C (1-3), with unique 6/5/6/6, 6/5/6/5/6, and 6/5/6/5 polycyclic systems were isolated from the alga-derived fungus Penicillium antarcticum KMM 4685. Their structures were elucidated by spectroscopic methods, X-ray diffraction, and quantum chemical calculations. A biogenetic pathway for 1-3 was proposed. Meroantarctines A-C (1-3) inhibited p-glycoprotein activity and could resensitize drug-resistant cancer cells to docetaxel.

Salvage Chemotherapy with Cisplatin, Ifosfamide, and Paclitaxel in Aggressive Variant of Metastatic Castration-Resistant Prostate Cancer

Significant progress has been achieved in the treatment of metastatic castration-resistant prostate cancer (mCRPC). However, results in patients with aggressive variant prostate cancer (AVPC) have been disappointing. Here, we report retrospectively collected data from intensively pretreated AVPC patients (n = 17; 88.2% visceral metastases; 82% elevation of neuroendocrine markers) treated with salvage chemotherapy consisting of cisplatin, ifosfamide, and paclitaxel (TIP). At the interim analysis, 60% of patients showed radiographic response or stable disease (PFS = 2.5 months; OS = 6 months). In men who responded to chemotherapy, an OS > 15 months was observed. Preclinical analyses confirmed the high activity of the TIP regimen, especially in docetaxel-resistant prostate cancer cells. This effect was primarily mediated by increased cisplatin sensitivity in the emergence of taxane resistance. Proteomic and functional analyses identified a lower DNA repair capacity and cell cycle machinery deficiency to be causative. In contrast, paclitaxel showed inconsistent effects, partially antagonizing cisplatin and ifosfamide in some AVPC models. Consequently, paclitaxel has been excluded from the TIP combination for future patients. In summary, we report for the first time the promising efficacy of TIP as salvage therapy in AVPC. Our preclinical data indicate a pivotal role for cisplatin in overcoming docetaxel resistance.

Cytotoxic N-Methylpretrichodermamide B Reveals Anticancer Activity and Inhibits P-Glycoprotein in Drug-Resistant Prostate Cancer Cells

N-methylpretrichodermamide B (NB) is a biologically active epidithiodiketopiperazine isolated from several strains of the algae-derived fungus Penicillium sp. Recently, we reported the first data on its activity in human cancer cells lines in vitro. Here, we investigated the activity, selectivity, and mechanism of action of NB in human prostate cancer cell lines, including drug-resistant subtypes. NB did not reveal cross-resistance to docetaxel in the PC3-DR cell line model and was highly active in hormone-independent 22Rv1 cells. NB-induced cell death was stipulated by externalization of phosphatidylserine and activation of caspase-3. Moreover, inhibition of caspase activity by z-VAD(OMe)-fmk did not affect NB cytotoxicity, suggesting a caspase-independent cell death induced by NB. The compound has a moderate p-glycoprotein (p-gp) substrate-like affinity and can simultaneously inhibit p-gp at nanomolar concentrations. Therefore, NB resensitized p-gp-overexpressing PC3-DR cells to docetaxel. A kinome profiling of the NB-treated cells revealed, among other things, an induction of mitogen-activated protein kinases JNK1/2 and p38. Further functional analysis confirmed an activation of both kinases and indicated a prosurvival role of this biological event in the cellular response to the treatment. Overall, NB holds promising anticancer potential and further structure-activity relationship studies and structural optimization are needed in order to improve its biological properties.

The Treatment of Metastatic, Hormone-Sensitive Prostatic Carcinoma

BACKGROUND

For many years, the standard treatment of metastatic, hormone-sensitive prostatic carcinoma (mHSPC) was androgen deprivation therapy (ADT) alone. By lowering the testosterone level into the castration range, ADT deprives the tumor of a key growth factor.

METHODS

For this article, we evaluated the treatment recommendations contained in national and international guidelines (German S3 guidelines and those of the European Society for Medical Oncology [ESMO], European Association of Urology [EAU], and National Comprehensive Cancer Network [NCCN]), as well as pertinent publications revealed by a PubMed search and the congress abstracts of the ESMO and of the American Society of Clinical Oncology [ASCO].

RESULTS

The past few years have witnessed fundamental changes in the treatment of mHSPC. Treatment intensification with docetaxel or with the new drugs directed against the androgen receptor signal pathway (abiraterone, apalutamide and enzalutamide) has been found to lower mortality by 19-40% and is now an integral component of first-line therapy. Relevant new findings have also been obtained with threefold combinations of ADT, docetaxel, and abiraterone or darolutamide. For patients with a light tumor burden, local radiotherapy of the primary tumor improves the probability of survival at 3 years by 8% (45.4 versus 49.1 months, difference 3.6 months; 95% confidence interval, 1.0 to 6.2 months).

CONCLUSION

The treatment of mHSPC is constantly changing. Phase III trials that are now in the recruitment stage, as well as our continually improving understanding of the underlying molecular-pathological mechanisms, will be altering the treatment landscape still further in the years to come.

New diterpenes from the marine sponge Spongionella sp. overcome drug resistance in prostate cancer by inhibition of P-glycoprotein

Spongian diterpenes are a group of marine natural compounds possessing various biological activities. However, their anticancer activity is still poorly studied and understood. We isolated six spongian diterpenes from the marine sponge Spongionella sp., including one new spongionellol A and five previously known molecules. The structures were elucidated using a detailed analysis MS and NMR spectra as well as by comparison with previously reported data. Two of them, namely, spongionellol A and 15,16-dideoxy-15α,17β-dihydroxy-15,17-oxidospongian-16-carboxylate-15,17-diacetate exhibited high activity and selectivity in human prostate cancer cells, including cells resistant to hormonal therapy and docetaxel. The mechanism of action has been identified as caspase-dependent apoptosis. Remarkably, both compounds were able to suppress expression of androgen receptor (AR) and AR-splice variant 7, as well as AR-dependent signaling. The isolated diterpenes effectively inhibited drug efflux mediated by multidrug-resistance protein 1 (MDR1; p-glycoprotein). Of note, a synergistic effect of the compounds with docetaxel, a substrate of p-glycoprotein, suggests resensitization of p-glycoprotein overexpressing cells to standard chemotherapy. In conclusion, the isolated spongian diterpenes possess high activity and selectivity towards prostate cancer cells combined with the ability to inhibit one of the main drug-resistance mechanism. This makes them promising candidates for combinational anticancer therapy.

1-O-Alkylglycerol Ethers from the Marine Sponge Guitarra abbotti and Their Cytotoxic Activity

The cytotoxicity-bioassay-guided fractionation of the ethanol extract from the marine sponge Guitarra abbotti, whose 1-O-alkyl-sn-glycerol ethers (AGEs) have not been investigated so far, led to the isolation of a complex lipid fraction containing, along with previously known compounds, six new lipids of the AGE type. The composition of the AGE fraction as well as the structures of 6 new and 22 previously known compounds were established using ¹H and ¹³C NMR, GC/MS, and chemical conversion methods. The new AGEs were identified as: 1-O-(Z-docos-15-enyl)-sn-glycerol (1), 1-O-(Z-docos-17-enyl)-sn-glycerol (2), 1-O-(Z-tricos-15-enyl)-sn-glycerol (3), 1-O-(Z-tricos-16-enyl)-sn-glycerol (4), 1-O-(Z-tricos-17-enyl)-sn-glycerol (5), and 1-O-(Z-tetracos-15-enyl)-sn-glycerol (6). The isolated AGEs show weak cytotoxic activity in THP-1, HL-60, HeLa, DLD-1, SNU C4, SK-MEL-28, and MDA-MB-231 human cancer cells. A further cytotoxicity analysis in JB6 P⁺ Cl41 cells bearing mutated MAP kinase genes revealed that ERK2 and JNK1 play a cytoprotective role in the cellular response to the AGE-induced cytotoxic effects.

New Antibacterial Chloro-Containing Polyketides from the Alga-Derived Fungus Asteromyces cruciatus KMM 4696

Six new polyketides acrucipentyns A–F (1–6) were isolated from the alga-derived fungus Asteromyces cruciatus KMM 4696. Their structures were established based on spectroscopic methods. The absolute configurations of acrucipentyn A was assigned by the modified Mosher’s method and ROESY data analysis. Acrucipentyns A–E were identified to be the very first examples of chlorine-containing asperpentyn-like compounds. The cytotoxic and antimicrobial activities of the isolated compounds were examined. Acrucipentyns A–F were found as antimicrobial agents, which inhibited sortase A enzyme activity, bacterial growth and biofilm formation of Staphylococcus aureus and decreased LDH release from human keratinocytes HaCaT in S. aureus skin infection in an in vitro model.

[Update on systemic treatment of urothelial cancer: therapy in transition]

The systemic treatment of locally advanced and metastatic urothelial carcinoma has been changing at a breathtaking pace for a few years. However, platinum-based chemotherapy continues to be the central component of perioperative therapies and first-line treatment in the metastatic stage. Immunotherapies with immune checkpoint inhibitors are now an integral part of therapy algorithms. New targeted forms of chemotherapy are about to be approved. Advances in understanding the molecular genetic analysis of tumour tissue will soon enable personalised therapy options. This article is intended to provide an overview of current systemic therapy options and the underlying database. New developments are identified by presenting ongoing phase III trials. After reading this article, the reader should feel informed about the current status of systemic therapy for urothelial carcinoma.

Aggressive variants of prostate cancer: underlying mechanisms of neuroendocrine transdifferentiation

Prostate cancer is a hormone-driven disease and its tumor cell growth highly relies on increased androgen receptor (AR) signaling. Therefore, targeted therapy directed against androgen synthesis or AR activation is broadly used and continually improved. However, a subset of patients eventually progresses to castration-resistant disease. To date, various mechanisms of resistance have been identified including the development of AR-independent aggressive variant prostate cancer based on neuroendocrine transdifferentiation (NED). Here, we review the highly complex processes contributing to NED. Genetic, epigenetic, transcriptional aberrations and posttranscriptional modifications are highlighted and the potential interplay of the different factors is discussed. Background Aggressive variant prostate cancer (AVPC) with traits of neuroendocrine differentiation emerges in a rising number of patients in recent years. Among others, advanced therapies targeting the androgen receptor axis have been considered causative for this development. Cell growth of AVPC often occurs completely independent of the androgen receptor signal transduction pathway and cells have mostly lost the typical cellular features of prostate adenocarcinoma. This complicates both diagnosis and treatment of this very aggressive disease. We believe that a deeper understanding of the complex molecular pathological mechanisms contributing to transdifferentiation will help to improve diagnostic procedures and develop effective treatment strategies. Indeed, in recent years, many scientists have made important contributions to unravel possible causes and mechanisms in the context of neuroendocrine transdifferentiation. However, the complexity of the diverse molecular pathways has not been captured completely, yet. This narrative review comprehensively highlights the individual steps of neuroendocrine transdifferentiation and makes an important contribution in bringing together the results found so far.

[CARD study: relevance for the treatment of advanced prostate cancer]

BACKGROUND

 Various life-prolonging therapy options are available for the treatment of metastatic castration-resistant prostate cancer (mCRPC).

OBJECTIVE

 The optimal therapy sequence for mCRPC has been discussed for years. With the final results of the CARD study, important prospective data are available to enlighten the discussion about the therapy sequence.

MATERIAL AND METHOD

 CARD is a randomised phase IV trial in patients with mCRPC who were previously treated with docetaxel and an anti-androgen receptor (ARTA). The study showed significant efficacy benefits in favour of further treatment with cabazitaxel versus a second ARTA therapy. The study results are presented and discussed in the context of previous study data with regard to their importance for everyday clinical practice.

RESULTS

 The CARD study data confirm cabazitaxel as an effective therapy option for mCRPC patients previously treated with docetaxel and an ARTA. Cabazitaxel was safe to apply. The study results confirm the cross resistance between the two ARTAs Abiraterone and Enzalutamide.

CONCLUSION

In mCRPC patients eligible for chemotherapy, the therapy sequence should be chosen so that the patients also receive cabazitaxel. A direct therapy sequence with two ARTAs should be avoided or, at least, only considered if other substances are contraindicated.

[Metastatic urothelial carcinoma-guideline-based therapy and new options]

Due to the approval of immuno-oncological therapies with immune checkpoint inhibitors, the treatment of metastatic urothelial carcinoma has become more complex in all lines of therapy. Thus, in first-line treatment, immunotherapy alone or immune maintenance therapy following platinum-based chemotherapy can be applied in addition to treatment with platinum-based combination therapies alone. In addition to the approval status and guideline recommendation, patient-specific factors such as comorbidities as well as patient preference must always be considered when choosing a therapy. In the following, we summarize the current data on treatment options in the first-line therapy of metastatic urothelial carcinoma and illustrate their practical application using a patient example.

[Cardiovascular side effects in patients undergoing androgen deprivation therapy: superiority of gonadotropin-releasing hormone antagonists? An update]

BACKGROUND

Androgen deprivation therapy (ADT) plays a crucial role in treatment of advanced prostate cancer (PCa). The additional application of new drugs results in prolonged overall survival, both in the hormone sensitive and castration resistant state. Consequently, the long-term use of ADT moves potential side effects into the focus of interest. In this context special consideration must be given to cardiovascular events.

OBJECTIVES

Review of current evidence on potential differences regarding the cardiovascular risk profile of gonadotropin-releasing hormone (GnRH) agonists compared to GnRH antagonists.

METHODS

Narrative review based on an expert consensus supported by a literature search in PubMed (MEDLINE) and the abstract databases of ASCO and ESMO was conducted for publications published between January 2015 and January 2021. Significant meta-analyses, randomized controlled trials (RCTs) and real-world data (RWD) revealing relevant results for clinical practice were taken into account. Selection of studies was performed based on the clinical relevance for everyday practice.

RESULTS

The search yielded three relevant meta-analyses, two prospective RCTs as well as three RWD publications that are of importance for clinical practice. Overall, a decreased incidence of cardiovascular events was reported for GnRH antagonists compared to GnRH agonists. Only one RWD publication described comparable rates of complications for both drug classes.

CONCLUSION

GnRH antagonists have a lower risk of treatment related cardiovascular events compared to GnRH agonists. Risks should be minimized by taking known cardiovascular risk factors into account before initiating therapy.

Activity of New Synthetic (2-Chloroethylthio)-1,4-naphthoquinones in Prostate Cancer Cells

Development of resistance to currently available standard therapies in advanced prostate cancer (PCa) emphasizes the need for novel therapeutic options. Here, we report the synthesis of new hybrid molecules consisting of 2-chloroethylthio and 1,4-naphthoquinone pharmacophores and describe their activity in PCa. In screening analyses, the introduction of one 2-chloroethylthio group improved the anticancer properties of 1,4-naphthoquinones, whereas the introduction of a second 2-chloroethylthio moiety rather decreased activity. Two most promising of the synthesized compounds, 30 and 32, were highly active in different human PCa cell lines harboring varying resistance profiles at nanomolar concentrations. The generated data suggest that the compounds are capable of mitochondria targeting, cytotoxic ROS induction, and DNA damage, which resulted in apoptosis presumably executed in a caspase-dependent manner. The substances synergized with the clinically approved PARP inhibitor olaparib and resensitized AR-V7-expressing PCa cells to antiandrogen enzalutamide, as well as to a combination of enzalutamide and an AKT inhibitor. This was at least in part exerted via down-regulation of AR-V7 expression and inhibition of AR signaling. Mild antagonism was observed in combination with platinum- or taxane-based chemotherapy, which was putatively related to treatment-induced activation of p38, JNK1/2, ERK1/2, MEK1/2, and AKT, functioning as potential pro-survival factors. Thus, the synthesized (2-chloroethylthio)-1,4-naphthoquinone derivatives exhibit promising anticancer properties in vitro, suggesting their further development as potential therapeutics for the treatment of castration-resistant PCa.

Cytotoxic Marine Alkaloid 3,10-Dibromofascaplysin Induces Apoptosis and Synergizes with Cytarabine Resulting in Leukemia Cell Death

Myeloid leukemia is a hematologic neoplasia characterized by a clonal proliferation of hematopoietic stem cell progenitors. Patient prognosis varies depending on the subtype of leukemia as well as eligibility for intensive treatment regimens and allogeneic stem cell transplantation. Although significant progress has been made in the therapy of patients including novel targeted treatment approaches, there is still an urgent need to optimize treatment outcome. The most common therapy is based on the use of chemotherapeutics cytarabine and anthrayclines. Here, we studied the effect of the recently synthesized marine alkaloid 3,10-dibromofascaplysin (DBF) in myeloid leukemia cells. Unsubstituted fascaplysin was early found to affect cell cycle via inhibiting CDK4/6, thus we compared the activity of DBF and other brominated derivatives with known CDK4/6 inhibitor palbociclib, which was earlier shown to be a promising candidate to treat leukemia. Unexpectedly, the effect DBF on cell cycle differs from palbociclib. In fact, DBF induced leukemic cells apoptosis and decreased the expression of genes responsible for cancer cell survival. Simultaneously, DBF was found to activate the E2F1 transcription factor. Using bioinformatical approaches we evaluated the possible molecular mechanisms, which may be associated with DBF-induced activation of E2F1. Finally, we found that DBF synergistically increase the cytotoxic effect of cytarabine in different myeloid leukemia cell lines. In conclusion, DBF is a promising drug candidate, which may be used in combinational therapeutics approaches to reduce leukemia cell growth.

A real-world comparison of docetaxel versus abiraterone acetate for metastatic hormone-sensitive prostate cancer

Background

Docetaxel (D) or secondary hormonal therapy (SHT) each combined with androgen deprivation therapy (ADT) represent possible treatment options in males with metastasized hormone‐sensitive prostate cancer (mHSPC). Real‐world data comparing different protocols are lacking yet. Thus, our objective was to compare the efficacy and safety of abiraterone acetate (AA)+ADT versus D+ADT in mHSPC.

Methods

In a retrospective multicenter analysis including males with mHSPC treated with either of the aforementioned protocols, overall survival (OS), progression‐free survival 1 (PFS1), and progression‐free survival 2 (PFS2) were assessed for both cohorts. Median time to event was tested by Kaplan–Meier method and log‐rank test. The Cox‐proportional hazards model was used for univariate and multivariate regression analyses.

Results

Overall, 196 patients were included. The AA+ADT cohort had a longer PFS1 in the log‐rank testing (23 vs. 13 mos., p < 0.001), a longer PFS2 (48 vs. 33 mos., p = 0.006), and longer OS (80 vs. 61 mos., p = 0.040). In the multivariate analyses AA+ADT outperformed D+ADT in terms of PFS1 (HR = 0.34, 95% CI = 0.183–0.623; p = 0.001) and PFS2 (HR = 0.33 95% CI = 0.128–0.827; p = 0.018), respectively, while OS and toxicity rate were similar between both groups.

Conclusions

AA+ADT is mainly associated with a similar efficacy and overall toxicity rate as D+ADT. Further prospective research is required for validation of the clinical value of the observed benefit of AA+ADT for progression‐free end‐points.

Cytoreductive radical prostatectomy after chemohormonal therapy in patients with primary metastatic prostate cancer

Objective

Methods

Results

Conclusion

New Deoxyisoaustamide Derivatives from the Coral-Derived Fungus Penicillium dimorphosporum KMM 4689

Seven new deoxyisoaustamide derivatives (1-7) together with known compounds (8-10) were isolated from the coral-derived fungus Penicillium dimorphosporum KMM 4689. Their structures were established using spectroscopic methods, X-ray diffraction analysis and by comparison with related known compounds. The absolute configurations of some alkaloids were determined based on CD and NOESY data as well as biogenetic considerations. The cytotoxic and neuroprotective activities of some of the isolated compounds were examined and structure-activity relationships were pointed out. New deoxyisoaustamides 4-6 at concentration of 1 µM revealed a statistical increase of PQ(paraquat)-treated Neuro-2a cell viability by 30-39%.

Sea Anemone Heteractis crispa Actinoporin Demonstrates In Vitro Anticancer Activities and Prevents HT-29 Colorectal Cancer Cell Migration

Actinoporins are the most abundant group of sea anemone cytolytic toxins. Their membranolytic activity is of high interest for the development of novel anticancer drugs. However, to date the activity of actinoporins in malignant cells has been poorly studied. Here, we report on recombinant analog of Hct-S3 (rHct-S3), belonging to the combinatory library of Heteractis crispa actinoporins. rHct-S3 exhibited cytotoxic activity against breast MDA-MB-231 (IC₅₀ = 7.3 µM), colorectal HT-29 (IC₅₀ = 6.8 µM), and melanoma SK-MEL-28 (IC₅₀ = 8.3 µM) cancer cells. The actinoporin effectively prevented epidermal growth factor -induced neoplastic transformation of JB6 Cl41 cells by 34% ± 0.2 and decreased colony formation of HT-29 cells by 47% ± 0.9, MDA-MB-231 cells by 37% ± 1.2, and SK-MEL-28 cells by 34% ± 3.6. Moreover, rHct-S3 decreased proliferation and suppressed migration of colorectal carcinoma cells by 31% ± 5.0 and 99% ± 6.4, respectively. The potent anti-migratory activity was proposed to mediate by decreased matrix metalloproteinases-2 and -9 expression. In addition, rHct-S3 induced programmed cell death by cleavage of caspase-3 and poly (ADP-ribose) polymerase, as well as regulation of Bax and Bcl-2. Our results indicate rHct-S3 to be a promising anticancer drug with a high anti-migratory potential.

Efficacy and Mechanism of Action of Marine Alkaloid 3,10-Dibromofascaplysin in Drug-Resistant Prostate Cancer Cells

Efficacy and mechanism of action of marine alkaloid 3,10-dibromofascaplysin (DBF) were investigated in human prostate cancer (PCa) cells harboring different levels of drug resistance. Anticancer activity was observed across all cell lines examined without signs of cross-resistance to androgen receptor targeting agents (ARTA) or taxane based chemotherapy. Kinome analysis followed by functional investigation identified JNK1/2 to be one of the molecular targets of DBF in 22Rv1 cells. In contrast, no activation of p38 and ERK1/2 MAPKs was observed. Inhibition of the drug-induced JNK1/2 activation or of the basal p38 activity resulted in increased cytotoxicity of DBF, whereas an active ERK1/2 was identified to be important for anticancer activity of the alkaloid. Synergistic effects of DBF were observed in combination with PARP-inhibitor olaparib most likely due to the induction of ROS production by the marine alkaloid. In addition, DBF intensified effects of platinum-based drugs cisplatin and carboplatin, and taxane derivatives docetaxel and cabazitaxel. Finally, DBF inhibited AR-signaling and resensitized AR-V7-positive 22Rv1 prostate cancer cells to enzalutamide, presumably due to AR-V7 down-regulation. These findings propose DBF to be a promising novel drug candidate for the treatment of human PCa regardless of resistance to standard therapy.

Consensus paper: current state of first- and second-line therapy in advanced clear-cell renal cell carcinoma

The therapy of advanced (clear-cell) renal cell carcinoma (RCC) has recently experienced tremendous changes. Several new treatments have been developed, with PD-1 immune-checkpoint inhibition being the backbone of therapy. Diverse immunotherapy combinations change current first-line standards. These changes also require new approaches in subsequent lines of therapy. In an expert panel, we discussed the new treatment options and how they change clinical practice. While first-line immunotherapies introduce a new level of response rates, data on second-line therapies remains poor. This scenario poses a challenge for clinicians as guideline recommendations are based on historical patient cohorts and agents may lack the appropriate label for their in guidelines recommended use. Here, we summarize relevant clinical data and consider appropriate treatment strategies.

Influence of Androgens on Immunity to Self and Foreign: Effects on Immunity and Cancer

It is well-known that sex hormones can directly and indirectly influence immune cell function. Different studies support a suppressive role of androgens on different components of the immune system by decreasing antibody production, T cell proliferation, NK cytotoxicity, and stimulating the production of anti-inflammatory cytokines. Androgen receptors have also been detected in many different cells of hematopoietic origin leading to direct effects of their ligands on the development and function of the immune system. The immunosuppressive properties of androgens could contribute to gender dimorphisms in autoimmune and infectious disease and thereby also hamper immune surveillance of tumors. Consistently, females generally are more prone to autoimmunity, while relatively less susceptible to infections, and have lower incidence and mortality of the majority of cancers compared to males. Some studies show that androgen deprivation therapy (ADT) can induce expansion of naïve T cells and increase T-cell responses. Emerging clinical data also reveal that ADT might enhance the efficacy of various immunotherapies including immune checkpoint blockade. In this review, we will discuss the potential role of androgens and their receptors in the immune responses in the context of different diseases. A particular focus will be on cancer, highlighting the effect of androgens on immune surveillance, tumor biology and on the efficacy of anti-cancer therapies including emerging immune therapies.

Leptogorgins A-C, Humulane Sesquiterpenoids from the Vietnamese Gorgonian Leptogorgia sp

Leptogorgins A-C (1-3), new humulane sesquiterpenoids, and leptogorgoid A (4), a new dihydroxyketosteroid, were isolated from the gorgonian Leptogorgia sp. collected from the South China Sea. The structures were established using MS and NMR data. The absolute configuration of 1 was confirmed by a modification of Mosher's method. Configurations of double bonds followed from NMR data, including NOE correlations. This is the first report of humulane-type sesquiterpenoids from marine invertebrates. Sesquiterpenoids leptogorgins A (1) and B (2) exhibited a moderate cytotoxicity and some selectivity against human drug-resistant prostate cancer cells 22Rv1.

Inspired by Sea Urchins: Warburg Effect Mediated Selectivity of Novel Synthetic Non-Glycoside 1,4-Naphthoquinone-6S-Glucose Conjugates in Prostate Cancer

The phenomenon of high sugar consumption by tumor cells is known as Warburg effect. It results from a high glycolysis rate, used by tumors as preferred metabolic pathway even in aerobic conditions. Targeting the Warburg effect to specifically deliver sugar conjugated cytotoxic compounds into tumor cells is a promising approach to create new selective drugs. We designed, synthesized, and analyzed a library of novel 6-S-(1,4-naphthoquinone-2-yl)-d-glucose chimera molecules (SABs)—novel sugar conjugates of 1,4-naphthoquinone analogs of the sea urchin pigments spinochromes, which have previously shown anticancer properties. A sulfur linker (thioether bond) was used to prevent potential hydrolysis by human glycoside-unspecific enzymes. The synthesized compounds exhibited a Warburg effect mediated selectivity to human prostate cancer cells (including highly drug-resistant cell lines). Mitochondria were identified as a primary cellular target of SABs. The mechanism of action included mitochondria membrane permeabilization, followed by ROS upregulation and release of cytotoxic mitochondrial proteins (AIF and cytochrome C) to the cytoplasm, which led to the consequent caspase-9 and -3 activation, PARP cleavage, and apoptosis-like cell death. These results enable us to further clinically develop these compounds for effective Warburg effect targeting.

Evaluation of PD-L1 expression on circulating tumor cells (CTCs) in patients with advanced urothelial carcinoma (UC)

Immune checkpoint inhibition (ICI) of the PD-1/PD-L1 axis shows durable responses in a subset of patients with metastatic urothelial carcinoma (UC). However, PD-L1 expression in tumor biopsies does not necessarily correlate with response to PD-1/PD-L1 inhibitors. Thus, a reliable predictive biomarker is urgently needed. Here, the expression of PD-L1 on circulating tumor cells (CTCs) in blood from patients with advanced UC was analyzed. For this purpose, an assay to test PD-L1 expression on CTCs using the CellSearch® system was established using cells of five UC cell lines spiked into blood samples from healthy donors and applied to a heterogeneous cohort of UC patients. Enumeration of CTCs was performed in blood samples from 49 patients with advanced UC. PD-L1 expression in ≥1 CTC was found in 10 of 16 CTC-positive samples (63%). Both intra- and inter-patient heterogeneity regarding PD-L1 expression of CTCs were observed. Furthermore, vimentin-expressing CTCs were detected in 4 of 15 CTC-positive samples (27%), independently of PD-L1 analysis. Both CTC detection and presence of CTCs with moderate or strong PD-L1 expression correlated with worse overall survival. Analyses during disease course of three individual patients receiving ICI suggest that apart from CTC numbers also PD-L1 expression on CTCs might potentially indicate disease progression.

This is the first study demonstrating the feasibility to detect CTC-PD-L1 expression in patients with advanced UC using the CellSearch® system. This assay is readily available for clinical application and could be implemented in future clinical trials to evaluate its relevance for predicting and monitoring response to ICI.

Detection of Androgen Receptor Variant 7 (ARV7) mRNA Levels in EpCAM-Enriched CTC Fractions for Monitoring Response to Androgen Targeting Therapies in Prostate Cancer

Expression of the androgen receptor splice variant 7 (ARV7) in circulating tumor cells (CTCs) has been associated with resistance towards novel androgen receptor (AR)-targeting therapies. While a multitude of ARV7 detection approaches have been developed, the simultaneous enumeration of CTCs and assessment of ARV7 status and the integration of validated technologies for CTC enrichment/detection into their workflow render interpretation of the results more difficult and/or require shipment to centralized labs. Here, we describe the establishment and technical validation of a novel ARV7 detection method integrating the CellSearch^® technology, the only FDA-cleared CTC-enrichment method for metastatic prostate cancer available so far. A highly sensitive and specific qPCR-based assay was developed, allowing detection of ARV7 and keratin 19 transcripts from as low as a single ARV7⁺/K19⁺ cell, even after 24 h of sample storage. Clinical feasibility was demonstrated on blood samples from 26 prostate cancer patients and assay sensitivity and specificity was corroborated. Our novel approach can now be included into prospective clinical trials aimed to assess the predictive values of CTC/ARV7 measurements in prostate cancer.

[50 years of systemic therapy of urinary bladder cancer]

This review summarises the treatment strategies of the last five decades for metastatic urothelial cancer. The introduction of combination chemotherapy in the mid-1980s led to clinically significant response rates and prolonged survival. Two years ago, the results of a phase-3 clinical trial with the PD1 inhibitor pembrolizumab for second-line treatment of metastatic urothelial carcinoma were published. These data were the first to show an overall survival benefit in comparison with a conventional chemotherapy with vinflunine, docetaxel or paclitaxel. Currently, PD1/PD-L1 inhibitors are also tested within randomized phase-3-trials for first-line treatment using different approaches either as a monotherapy or a combination with conventional chemotherapy or CTLA-4 inhibitors. Whereas data from single-arm phase-2 clinical trials have already been published, first phase-3 data are expected in 2019.

Naphto-Γ-pyrones from the marine-derived fungus Aspergillus foetidus

Nine naphto-γ-pyrones rubrofusarine B (1), TMC 256 A1 (2), fansecinones A (3) and B (4), aurasperones A (5), B (6) and F (7), dianhydro-aurasperone C (8) and asperpyrone B (9) were isolated from the marine-derived fungus Aspergillus foetidus KMM 4694. Their structures were established based on spectroscopic methods. The effect of the substances on viability and colony formation of human drug-resistant prostate cancer 22Rv1 cell was evaluated.

Response to olaparib in a PALB2 germline mutated prostate cancer and genetic events associated with resistance

Prostate cancers harboring DNA repair gene alterations are particularly sensitive to PARP inhibitor treatment. We report a case of an advanced prostate cancer patient profiled within the NCT-MASTER (Molecularly Aided Stratification for Tumor Eradication Research) precision oncology program using next-generation sequencing. Comprehensive genomic and transcriptomic analysis identified a pathogenic germline PALB2 variant as well as a mutational signature associated with disturbed homologous recombination together with structural genomic rearrangements. A molecular tumor board identified a potential benefit of targeted therapy and recommended PARP inhibition and platinum-based chemotherapy. Single-agent treatment with the PARP inhibitor olaparib as well as subsequent combination with platinum-based chemotherapy resulted in disease stabilization and substantial improvement of clinical symptoms. Upon progression, we performed whole-exome and RNA sequencing of a liver metastasis, which demonstrated up-regulation of several genes characteristic for the neuroendocrine prostate cancer phenotype as well as a novel translocation resulting in an in-frame, loss-of-function fusion of RB1. We suggest that multidimensional genomic characterization of prostate cancer patients undergoing PARP inhibitor therapy will be necessary to capture and understand predictive biomarkers of PARP inhibitor sensitivity and resistance.

Citriperazines A-D produced by a marine algae-derived fungus Penicillium sp. KMM 4672

Four new diketopiperazine alkaloids, citriperazines A-D were isolated from algae-derived Penicillium sp. KMM 4672. The structures of compounds 1-4 were determined using spectroscopic methods. The absolute configurations of compounds 1 and 4 were established by comparison of calculated and experimental ECD spectra. The cytotoxicity of compounds 1-4 against several human prostate cell lines was evaluated.

Auroglaucin-related neuroprotective compounds from Vietnamese marine sediment-derived fungus Aspergillus niveoglaucus

Two new auroglaucin-derived compounds, niveoglaucins A (1) and B (2), together with four known related compounds were isolated from extract of the marine sediment-derived strain of Aspergillus niveoglaucus. The structures of these compounds were determined by 1D and 2D NMR spectroscopy and high resolution MS. The plausible biosynthetic pathway was proposed for new compounds 1 and 2. The neuroprotective activity in 6-OHDA-induced Parkinson's disease cell model was shown for niveoglaucin A (1).

Cost-effectiveness analyses and cost analyses in castration-resistant prostate cancer: A systematic review

Background

Treatment of metastatic prostate cancer is associated with high personal and economic burden. Recently, new treatment options for castration-resistant prostate cancer became available with promising survival advantages. However, cost-effectiveness of those new treatment options is sometimes ambiguous or given only under certain circumstances. The aim of this study was to systematically review studies on the cost-effectiveness of treatments and costs of castration-resistant prostate cancer (CRPC) and metastasizing castration-resistant prostate cancer (mCRPC) on their methodological quality and the risk of bias.

Methods

A systematic literature search was performed in the databases PubMed, CINAHL Complete, the Cochrane Library and Web of Science Core Collection for costs-effectiveness analyses, model-based economic evaluations, cost-of-illness analyses and budget impact analyses. Reported costs were inflated to 2015 US$ purchasing power parities. Quality assessment and risk of bias assessment was performed using the Consolidated Health Economic Evaluation Reporting Standards checklist and the Bias in Economic Evaluations checklist, respectively.

Results

In total, 38 articles were identified by the systematic literature search. The methodological quality of the included studies varied widely, and there was considerable risk of bias. The cost-effectiveness treatments for CRPC and mCRPC was assessed with incremental cost-effectiveness ratios ranging from dominance for mitoxantrone to $562,328 per quality-adjusted life year gained for sipuleucel-T compared with prednisone alone. Annual costs for the treatment of castration-resistant prostate cancer ranged from $3,067 to $77,725.

Conclusion

The cost-effectiveness of treatments of CRPC strongly depended on the willingness to pay per quality-adjusted life year gained/life-year saved throughout all included costs-effectiveness analyses and model-based economic evaluations. High-quality cost-effectiveness analyses based on randomized controlled trials are needed in order to make informed decisions on the management of castration-resistant prostate cancer and the resulting financial impact on the healthcare system.