Preclinical knowledge of dysregulated pathways and potential biomarkers for urological cancers has undergone limited translation into the clinic. Moreover, the low approval rate of new anticancer ...drugs and the heterogeneous drug responses in patients indicate that current preclinical models do not always reflect the complexity of malignant disease. Patient-derived tumour models used in preclinical uro-oncology research include 3D culture systems, organotypic tissue slices and patient-derived xenograft models. Technological innovations have enabled major improvements in the capacity of these tumour models to reproduce the clinical complexity of urological cancers. Each type of patient-derived model has inherent advantages and limitations that can be exploited, either alone or in combination, to gather specific knowledge on clinical challenges and address unmet clinical needs. Nevertheless, few opportunities exist for patients with urological cancers to benefit from personalized therapeutic approaches. Clinical validation of experimental data is needed to facilitate the translation and implementation of preclinical knowledge into treatment decision making.
The androgen receptor (AR) is a crucial player in various aspects of male reproduction and has been associated with the development and progression of prostate cancer (PCa). Therefore, the protein is ...the linchpin of current PCa therapies. Despite great research efforts, the AR signaling pathway has still not been deciphered, and the emergence of resistance is still the biggest problem in PCa treatment. To discuss the latest developments in AR research, the "1st International Androgen Receptor Symposium" offered a forum for the exchange of clinical and scientific innovations around the role of the AR in prostate cancer (PCa) and to stimulate new collaborative interactions among leading scientists from basic, translational, and clinical research. The symposium included three sessions covering preclinical studies, prognostic and diagnostic biomarkers, and ongoing prostate cancer clinical trials. In addition, a panel discussion about the future direction of androgen deprivation therapy and anti-AR therapy in PCa was conducted. Therefore, the newest insights and developments in therapeutic strategies and biomarkers are discussed in this report.
Repurposing FDA‐approved, antipsychotic cationic amphiphilic drugs like penfluridol dose‐dependently decreased viability of human bladder cancer cells, significantly reduced tumor progression and ...metastasis in an orthotopic human bladder cancer xenograft model, and induced significant antitumor responses in patient‐derived, ex vivo cultured bladder cancer tissue. Clinically approved penfluridol is a promising antineoplastic agent for bladder cancer patients for which effective therapy is currently lacking.
More effective therapy for patients with either muscle‐invasive or high‐risk non‐muscle‐invasive urothelial carcinoma of the bladder (UCB) is an unmet clinical need. For this, drug repositioning of clinically approved drugs represents an interesting approach. By repurposing existing drugs, alternative anticancer therapies can be introduced in the clinic relatively fast, because the safety and dosing of these clinically approved pharmacological agents are generally well known. Cationic amphiphilic drugs (CADs) dose‐dependently decreased the viability of a panel of human UCB lines in vitro. CADs induced lysosomal puncta formation, a hallmark of lysosomal leakage. Intravesical instillation of the CAD penfluridol in an orthotopic mouse xenograft model of human UCB resulted in significantly reduced intravesical tumor growth and metastatic progression. Furthermore, treatment of patient‐derived ex vivo cultured human UCB tissue caused significant partial or complete antitumor responses in 97% of the explanted tumor tissues. In conclusion, penfluridol represents a promising treatment option for bladder cancer patients and warrants further clinical evaluation.
Urological malignancies, including prostate and bladder carcinoma, represent a major clinical problem due to the frequent occurrence of therapy resistance and the formation of incurable distant ...metastases. As a result, there is an urgent need for versatile and predictive disease models for the assessment of the individualized drug response in urological malignancies. Compound testing on
cultured patient-derived tumor tissues could represent a promising approach. In this study, we have optimized an
culture system of explanted human prostate and bladder tumors derived from clinical specimens and human cancer cell lines xenografted in mice. The explanted and cultured tumor slices remained viable and tissue architecture could be maintained for up to 10 days of culture. Treatment of
cultured human prostate and bladder cancer tissues with docetaxel and gemcitabine, respectively, resulted in a dose-dependent anti-tumor response. The dose-dependent decrease in tumor cells upon administration of the chemotherapeutic agents was preceded by an induction of apoptosis. The implementation and optimization of the tissue slice technology may facilitate the assessment of anti-tumor efficacies of existing and candidate pharmacological agents in the complex multicellular neoplastic tissues from prostate and bladder cancer patients. Our model represents a versatile "near-patient" tool to determine tumor-targeted and/or stroma-mediated anti-neoplastic responses, thus contributing to the field of personalized therapeutics.
To isolate, culture, and characterize primary human choroidal endothelial cells, and to assess their responsiveness to corticosteroids, in order to enable knowledge gain on the pathogenesis of ...central serous chorioretinopathy.
Choroidal endothelial cells were isolated from cadaveric human donors. Magnetic-activated cell sorting with anti-human CD31 was performed for choroidal endothelial cell isolation. Primary cultures of purified choroidal endothelial cells were treated with several regimens of corticosteroids and analyzed for effects on primary corticosteroid responsive genes.
Isolated choroidal endothelial cell cultures had a cobblestone appearance in monolayer cultures and stained positive for vascular endothelial cadherin. Moreover, on a 3D-Matrigel matrix, these cells formed capillary-like structures, characteristic of in vitro endothelial cells. Primary cultures of purified choroidal endothelial cells treated with several regimens of corticosteroids demonstrated significant transcriptional upregulation of primary corticosteroid responsive genes (FKBP5, PER1, GILZ, and SGK1). Further pharmacologic analysis using specific agonists (dexamethasone, aldosterone) and antagonists (mifepristone, spironolactone) for either the glucocorticoid receptor or the mineralocorticoid receptor showed that this response was exclusively mediated by the glucocorticoid receptor in our model.
With this optimized choroidal endothelial cell isolation and culturing protocol, we have established an in vitro model that appears very suitable for research on both central serous chorioretinopathy and other diseases in which corticosteroids and choroidal endothelial cells are involved. Our model proves to be suitable for studying effects mediated through the glucocorticoid receptor. The role of mineralocorticoid receptor-mediated effects needs further research, both in vivo and in cell model development.
Transformed epithelial cells can activate programs of epithelial plasticity and switch from a sessile, epithelial phenotype to a motile, mesenchymal phenotype. This process is linked to the ...acquisition of an invasive phenotype and the formation of distant metastases. The development of compounds that block the acquisition of an invasive phenotype or revert the invasive mesenchymal phenotype into a more differentiated epithelial phenotype represent a promising anticancer strategy. In a high-throughput assay based on E-cadherin (re)induction and the inhibition of tumor cell invasion, 44,475 low molecular weight (LMW) compounds were screened. The screening resulted in the identification of candidate compounds from the PROAM02 class. Selected LMW compounds activated E-cadherin promoter activity and inhibited cancer cell invasion in multiple metastatic human cancer cell lines. The intraperitoneal administration of selected LMW compounds reduced the tumor burden in human prostate and breast cancer in vivo mouse models. Moreover, selected LMW compounds decreased the intra-bone growth of xenografted human prostate cancer cells. This study describes the identification of the PROAM02 class of small molecules that can be exploited to reduce cancer cell invasion and metastases. Further clinical evaluation of selected candidate inhibitors is warranted to address their safety, bioavailability and antitumor efficacy in the management of patients with aggressive cancers.
Treatment of castration-resistant prostate cancer remains a challenging clinical problem. Despite the promising effects of immunotherapy in other solid cancers, prostate cancer has remained largely ...unresponsive. Oncolytic viruses represent a promising therapeutic avenue, as oncolytic virus treatment combines tumour cell lysis with activation of the immune system and mounting of effective anti-tumour responses. Mammalian Orthoreoviruses are non-pathogenic human viruses with a preference of lytic replication in human tumour cells. In this study, we evaluated the oncolytic efficacy of the bioselected oncolytic reovirus mutant jin-3 in multiple human prostate cancer models. The jin-3 reovirus displayed efficient infection, replication, and anti-cancer responses in 2D and 3D prostate cancer models, as well as in ex vivo cultured human tumour slices. In addition, the jin-3 reovirus markedly reduced the viability and growth of human cancer cell lines and patient-derived xenografts. The infection induced the expression of mediators of immunogenic cell death, interferon-stimulated genes, and inflammatory cytokines. Taken together, our data demonstrate that the reovirus mutant jin-3 displays tumour tropism, and induces potent oncolytic and immunomodulatory responses in human prostate cancer models. Therefore, jin-3 reovirus represents an attractive candidate for further development as oncolytic agent for treatment of patients with aggressive localised or advanced prostate cancer.
Abstract
The acquisition of therapy resistance and the formation of distant metastases represent major problems in prostate cancer. To date, immunotherapeutic approaches have been relatively ...disappointing in the treatment of prostate cancer. Therapies based on oncolytic viruses are being exploited for several tumor entities and have been studied in multiple clinical trials. Mammalian orthoreovirus is a non-enveloped double stranded RNA virus that has not been linked to serious disease in humans. Reovirus is relatively safe to use and several clinical trials are currently ongoing to study the oncolytic effect of reovirus in various tumor types. Type 3 Dearing (T3D) is a promising candidate for the use as an oncolytic agent. Besides wildtype T3D reovirus (R124), spontaneous mutants Jin1, 2 and 3 were generated which harbor mutations in spike protein Sigma-1. In this way, Jin mutants are able to infect cells independently of the Junction Adhesion Molecule-A (JAM-A) entry receptor on the tumor cell surface, which is often downregulated in different types of cancer.
In this study, the direct oncolytic effect of wildtype (R124) and Jin mutant reovirus was examined in human prostate cancer cells in vitro and in our ‘near-patient’ model of ex vivo cultured human prostate cancer tissue slices. Both R124 and Jin3 dose-dependently induced prostate cancer cell death in PC-3M-Pro4luc2, DU145 and 22Rv1 cells in vitro. Interestingly, JAM-A negative cancer cells were insensitive for R124, but were effectively killed by Jin1 mutant, indicating the beneficial effects of the Jin mutant in JAM-A low/negative tumors. Moreover, tumor tissue slices were generated from explanted patient prostate cancer tissues and patient-derived xenografts (PDX) and cultured with reovirus. Oncolytic effects were observed in ex vivo cultured tumor slices upon viral replication and subsequent stimulation of apoptosis. Therefore, ex vivo culture of patient-derived tumor tissue allows the assessment of individual anti-tumor response of the oncolytic virotherapy (i.e. personalized therapeutics). Taken together, our results indicate that both wildtype R124 virus and mutant Jin reovirus can infect and replicate in human prostate cancer cells and patient-derived prostate cancer tissues. The Jin mutants are of particular interest in JAM-A negative tumors. The indirect immunomodulatory effects of reovirus in human prostate cancer are currently ongoing.
In conclusion, our selected oncolytic reoviruses may represent a promising novel treatment strategy in human prostate cancer alone or combined with immunostimulatory agents.
Citation Format: Arjanneke F. van de Merbel, Geertje van der Horst, Maaike H. van der Mark, Diana J. van den Wollenberg, Jack A. Schalken, Anne Collins, Norman J. Maitland, Rob C. Hoeben, Gabri van der Pluijm. Oncolytic reovirus variants induce direct oncolysis in human prostate cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 349.
Abstract
Urothelial carcinoma of the bladder (UCB) is the fifth most common cancer in the western world. UCB present either as non-muscle-invasive BC (NMIBC) or as muscle-invasive carcinomas (MIBC). ...NMIBC is characterized by a high risk of recurrence and even progression to MIBC based on clinicopathological risk factors. Despite radical surgery and extensive chemotherapy, the outcome of MIBC patients is poor. High-risk NMIBC is treated with adjuvant intravesical instillations with Bacillus Calmette-Guérin (BCG). However, a substantial number of patients do not tolerate BCG or do not respond. Novel therapy for patients who do not tolerate BCG or in who are BCG unresponsive is a clear unmet clinical need. Drug repositioning of existing FDA-approved drugs could be a promising opportunity. Recently, cationic amphiphilic drugs (CADs), including commonly used antidepressants, antihistamines and antipsychotics were found to preferentially induce lysosomal cell death in transformed cells. In this study, we evaluated the potential anti-tumor efficacy and toxicity of these drugs in in vitro assays, in vivo preclinical models, and in and ex-vivo cultured patient-derived bladder cancer tissue slices. Treatment with CADs resulted in a significant dose-dependent decrease in proliferation and viability of multiple human UCB cell lines (a.o. RT4, TCC-SUP, and UM-UC-3) in vitro. Consistent with previous data regarding the ability of CADs to induce lysosomal membrane permeabilization in other solid cancer cells, we observed lysosomal puncta formation, which is a hallmark of lysosomal leakage. Strikingly, instillation of CADs in preclinical in vivo models of orthotopically growing human UM-UC-3 UCB resulted in a significant reduction in orthotopic as well as metastatic tumor burden. In line with these data, treatment of 39 patient-derived ex vivo cultured UCB slices with penfluridol resulted in significant anti-tumor responses ranging from complete regression to a significant reduction of the tumor.In vivo experiments revealed that normal mouse urothelium is not affected upon bladder instillation of CADs (weekly instillation of penfluridol for 5 weeks) in non-tumor bearing nude mice. In addition, penfluridol treatment of ex vivo cultured normal human urothelium only marginally affected the tissue. In conclusion, we demonstrated that CADs can target UCB cells and might be a promising novel approach for treatment of UCB.
Citation Format: Geertje van der Horst, Arjanneke F. van de Merbel, Eline Ruigrok, Maaike H. van der Mark, Emily Ploeg, Marja Jäätelä, Janneke van Uhm, Rob C. Pelger, Chris H. Bangma, Joost Boormans, Gabri van der Pluijm, Ellen C. Zwarthoff. Cationic amphiphilic drugs as a potential new treatment option for patients with high risk non-muscle invasive bladder cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1932.
Abstract
Immunotherapy, including the use of immune checkpoint inhibitors, has emerged as an attractive strategy for treatment of various cancers. Unfortunately, less than half of the bladder cancer ...patients demonstrate clinical benefit from immune checkpoint inhibitors. Novel therapeutic approaches such as oncolytic virotherapy may unleash the full potential of immunotherapy. Oncolytic viruses display tumor-lysing properties, while leaving normal cells unharmed. Besides the direct oncolytic effects, oncolytic viruses are capable of inducing systemic anti-tumor immune responses, thereby representing a promising anti-cancer therapy. In our multi-center oncolytic viro-immunotherapy (OVIT) consortium we evaluate and compare the oncolytic and immunomodulatory properties of several oncolytic viruses (reoviruses, novel non-human primate Adenoviruses, Newcastle disease virus), develop tools to predict oncolytic virus efficacy and design strategies to personalize oncolytic virus therapy. In this study we evaluated and compared the direct oncolytic and indirect immunostimulatory effects of wildtype reovirus R124 and mutant reovirus jin-3 in human bladder cancer. Mutant reovirus jin-3 harbors mutations in the spike protein Sigma-1 and can infect cells independently of junction adhesion molecule A (JAM-A) expression on the tumor cell surface. For this, we exploited multiple preclinical bladder cancer models, including patient-derived tumor models (e.g. 3D cultures) and ex-vivo cultured tumor tissue slices. Both R124 and jin-3 reoviruses could infect, replicate and induce cell death in a panel of 2D and 3D cultured bladder cancer cells lines with a basal, luminal or mixed phenotype. Furthermore, the viruses were capable of infecting the tumor cells and induced cell death in ex-vivo cultured tumor tissue slices. Reovirus mutant jin-3, and to a lesser extent R124, strongly induced immunogenic cell death markers (HMGB1, cell surface expression of calreticulin, HSP90), interferon-stimulated genes, and inflammatory cytokines (IFNβ, CXCL10, TNFα) in human bladder cancer cells. Co-culture of reovirus-infected murine bladder cancer cells MB-49 with murine splenocytes resulted in increased activation markers of dendritic cells and NK cells. In conclusion, reoviruses display oncolytic properties in multiple preclinical models of human bladder cancer. Mutant reovirus jin-3 displays more potent immunomodulatory responses in preclinical bladder cancer models compared with wildtype reovirus R124. Therefore, jin-3 represents an attractive candidate for clinical translation.
Citation Format: Arjanneke F. Van De Merbel, Maaike H. van der Mark, Thijs J. Janssen, Lobke C. Hensen, Diana J. van den Wollenberg, Rob C. Hoeben, Rob F. Bevers, Rob C. Pelger, Gabri van der Pluijm, Geertje van der Horst. Mammalian orthoreoviruses R124 and jin-3 demonstrate oncolytic and immune-stimulatory effects in human preclinical bladder cancer models 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 1845.
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