The use of T-cell receptor (TCR) gene transfer for the treatment of both hematological and solid tumors is increasing. Using TCR gene transfer T cells can be redirected to target tumor or lineage... Show moreThe use of T-cell receptor (TCR) gene transfer for the treatment of both hematological and solid tumors is increasing. Using TCR gene transfer T cells can be redirected to target tumor or lineage-specific antigens. Especially for poor immunogenic tumors this offers the potential to circumvent limitations of the endogenous T-cell repertoire. Still, the broad use of TCR-based therapy is hampered by a limited number of targeted antigens and HLA class I binding restrictions of TCRs. Furthermore, several of the pioneering T-cell based therapies have demonstrated that the balance between therapeutic efficacy and safety remains a challenge as T-cell mediated toxicities have occurred. In this thesis we identified novel targets, peptides and TCRs in order to treat a broader patient population, among others ovarian and prostate cancer patients. We stringently selected appropriate tumor- and lineage-specific targets using a differential gene expression analysis, and identified naturally expressed peptides from the HLA class I associated ligandome. We isolated peptide-specific T cells, sequenced their TCRs and carefully selected the most promising TCRs. Overall, we selected ten TCRs that demonstrated an effective and safe reactivity pattern based on the performed T-cell reactivity screenings. These TCRs demonstrated reactivity against broad panels of patient-derived tumor samples and/or tumor cell lines, without reactivity against a broad variety of healthy cell subsets or other antigen negative cells. Furthermore, in this thesis we set up human induced pluripotent stem cell (hiPSC)-derived models to additionally examine toxicity risks of T cells against vital organs or specialized cell subsets. We demonstrated added value of these models in determining toxicity risks in the preclinical pipeline of TCRs. Show less
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... Show moreIn 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. Show less
Prostate cancer (PCa) is one of the most prevalent cancer in males. Although the majority of the patients can benefit from the present clinical treatments, 20%-30% of the patients who originally... Show moreProstate cancer (PCa) is one of the most prevalent cancer in males. Although the majority of the patients can benefit from the present clinical treatments, 20%-30% of the patients who originally respond to the therapy still develop incurable, castration-resistance bone metastases, which is a main cause of death in PCa . In this thesis, I combined an advanced zebrafish xenograft model with in vitro cellular approaches and mice xenografts to study the early stage of PCa metastasis. Using this comprehensive esearch platform, I identified multiple key signaling pathways that play essential roles in promoting the onset of PCa metastatis. The pathways I discovered include Cripto-associated EMT plasticity, CDC-42-N-Wasp-Cortactin associated mechanosensing and mechanotransduction, microenvironment dependent NF-ĸB-Activin A signaling pathway, and AMPK-Autophagy dependent metabolic stress coping pathway. Show less
Once prostate cancer has spread to the skeleton, patients cannot be cured from their disease. Identification of the cell(s) of origin of prostate cancer as well as the neoplastic cell(s) involved... Show moreOnce prostate cancer has spread to the skeleton, patients cannot be cured from their disease. Identification of the cell(s) of origin of prostate cancer as well as the neoplastic cell(s) involved in the formation of distant metastases is, therefore, fundamental to understanding of carcinogenesis and metastasis. The functional identification of metastasis-initiating cells is a prerequisite for properly targeted therapy of metastatic disease in advanced prostate cancer. In chapter 2 of this thesis, the possible use of aldehyde dehydrogenase (ALDH) as marker for the identification and isolation of tumor-initiating and metastasis-initiating cells in prostate cancer is studied. In chapter 3, the functional role of a single ALDH isoform (ALDH7A1) in metastatic prostate cancer is investigated by knockdown studies in vitro and in vivo. In chapter 4, the functional involvement of _v integrins in the formation of a metastatic stem/progenitor prostate cancer phenotype is studied. Subsequently, in chapter 5, the targeting of integrins by a novel non-peptide integrin antagonist is evaluated in vitro and in preclinical models of prostate cancer progression and metastasis. Finally, general conclusions and discussions are described in chapter 6. Show less
