Preclinical and 'near-patient' models for the evaluation of experimental therapy in prostate and bladder cancer

In this thesis, different preclinical strategies were explored aiming at the identification of putative novel therapies for prostate and bladder cancer. The first part of this thesis (Chapter 2 and Chapter 3) describes the generationof preclinical, patient-derived model systems of prostate and bladder cancer. In Chapter 2, an overview is provided of the most commonly used patient-derived model systems for urological tumors, and a framework on how these patient derived tumor models can be employed to address preclinical and clinical unmet needs is presented. In Chapter 3, we developed and optimized the culture of ex vivo tumor tissue slices and employed this model to detect anti-tumor responses of chemotherapeutic agents Docetaxel and Gemicitabin. Subsequently in Chapters 4, 5 and 6, we describe the use of multiple preclinical translational models, including patient-derived tumor models. In Chapter 4 and 5 the translational potential of the approved antipsychotic drug penfluridol was determined in bladder and prostate cancer. In Chapter 6, the use of oncolytic reovirus jin-3 as putative novel therapeutic strategy for the treatment of prostate is investigated. Finally, in Chapter 7, we describe a novel preclinical screening strategy based on E-cadherin (re)induction and inhibition of invasion for the identification of a new class of small molecules for the treatment of aggressive epithelial cancers.LUMC / Geneeskund

The identification of small molecule inhibitors that reduce invasion and metastasis of aggressive cancers

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.Prostatic carcinom

Reovirus mutant jin-3 exhibits lytic and immune-stimulatory effects in preclinical human prostate cancer models

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.Experimental cancer immunology and therap

Cationic amphiphilic drugs as potential anticancer therapy for bladder cancer

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 amp

miR-25 is a key regulator of prostate cancer invasiveness by modulation of the cross-talk between Notch and TGF-beta signaling

Prostatic carcinom

miR-25 Modulates Invasivenessand Dissemination of Human Prostate Cancer Cells via Regulation of alpha(v)- and alpha(6)-Integrin Expression

Prostatic carcinom

The Effect of Corticosteroids on Human Choroidal Endothelial Cells: A Model to Study Central Serous Chorioretinopathy

Vascular Surger