Current sexual health care has not yet succeeded to guide men and their partners sufficiently when it comes to dealing with the consequences of prostate cancer (PCa) diagnosis and treatment. The... Show moreCurrent sexual health care has not yet succeeded to guide men and their partners sufficiently when it comes to dealing with the consequences of prostate cancer (PCa) diagnosis and treatment. The majority of men need a standardized consultation with a specialized healthcare provider (HCP) to discuss sexual health issues preferably within three months after treatment. Although current written information provision coming from urology departments discusses sexual health more often than radiotherapy departments; sexual dysfunction (SD) is still not routinely addressed. Focus during consultations is mostly on men while most of the partners also experience difficulties when dealing with sexual side effects. Regarding HCPs, urology residents experience lack of knowledge and competence to treat SD after PCa treatment and an unmet need exists for additional education and training. A symposium on sexual health care in PCa led to an increase of awareness to discuss SD more often during consultations. In case HCPs feel lack of knowledge, competence, time or tools to discuss sexual health after PCa treatment, referral to a specialized HCP should occur; according to the needs and preferences of men and their partners. However, management of outpatient clinics and availability of referral options are still in need of melioration. Show less
Wang, W.; Nier, C.R. de; Wuhrer, M.; Lageveen-Kammeijer, G.S.M. 2023
Prostate-specific antigen (PSA) is a well-known clinical biomarker in prostate cancer (PCa) diagnosis, but a better test is still needed, as the serum-level-based PSA quantification exhibits... Show moreProstate-specific antigen (PSA) is a well-known clinical biomarker in prostate cancer (PCa) diagnosis, but a better test is still needed, as the serum-level-based PSA quantification exhibits limited specificity and comes with poor predictive value. Prior to PSA, prostatic acid phosphatase (PAP) was used, but it was replaced by PSA because PSA improved the early detection of PCa. Upon revisiting PAP and its glycosylation specifically, it appears to be a promising new biomarker candidate. Namely, previous studies have indicated that PAP glycoforms differ between PCa and non-PCa individuals. However, an in-depth characterization of PAP glycosylation is still lacking. In this study, we established an in-depth glycoproteomic assay for urinary PAP by characterizing both the micro- and macroheterogeneity of the PAP glycoprofile. For this purpose, PAP samples were analyzed by capillary electrophoresis coupled to mass spectrometry after affinity purification from urine and proteolytic digestion. The developed urinary PAP assay was applied on a pooled DRE (digital rectal examination) urine sample from nine individuals. Three glycosylation sites were characterized, namely N-94, N-220, and N-333, via N-glycopeptide analysis. Taking sialic acid linkage isomers into account, a total of 63, 27, and 4 N-glycan structures were identified, respectively. The presented PAP glycoproteomic assay will enable the determination of potential glycomic biomarkers for the early detection and prognosis of PCa in cohort studies. Show less
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
Schepens, M.H.J.; Hooff, M.L. van; Galien, O. van der; Plantes, C.M.P.Z. des; Somford, D.M.; Leeuwen, P.J. van; ... ; Limbeek, J. van 2023
BackgroundOn the basis of previous analyses of the incidence of urinary incontinence (UI) after radical prostatectomy (RP), the hospital RP volume threshold in the Netherlands was gradually... Show moreBackgroundOn the basis of previous analyses of the incidence of urinary incontinence (UI) after radical prostatectomy (RP), the hospital RP volume threshold in the Netherlands was gradually increased from 20 per year in 2017, to 50 in 2018 and 100 from 2019 onwards.ObjectiveTo evaluate the impact of hospital RP volumes on the incidence and risk of UI after RP (RP-UI).Design, setting, and participantsPatients who underwent RP during 2016–2020 were identified in the claims database of the largest health insurance company in the Netherlands. Incontinence was defined as an insurance claim for ≥1 pads/d.Outcome measurements and statistical analysisThe relationship between hospital RP volume (HV) and RP-UI was assessed via multivariable analysis adjusted for age, comorbidity, postoperative radiotherapy, and lymph node dissection.Results and limitationsRP-UI incidence nationwide and by RP volume category did not decrease significantly during the study period, and 5-yr RP-UI rates varied greatly among hospitals (19–85%). However, low-volume hospitals (≤120 RPs/yr) had a higher percentage of patients with RP-UI and higher variation in comparison to high-volume hospitals (>120 RPs/yr). In comparison to hospitals with low RP volumes throughout the study period, the risk of RP-UI was 29% lower in hospitals shifting from the low-volume to the high-volume category (>120 RPs/yr) and 52% lower in hospitals with a high RP volume throughout the study period (>120 RPs/yr for 5 yr).ConclusionsA focus on increasing hospital RP volumes alone does not seem to be sufficient to reduce the incidence of RP-UI, at least in the short term. Measurement of outcomes, preferably per surgeon, and the introduction of quality assurance programs are recommended.Patient summaryIn the Netherlands, centralization of surgery to remove the prostate (RP) because of cancer has not yet improved the occurrence of urinary incontinence (UI) after surgery. Hospitals performing more than 120 RP operations per year had better UI outcomes. However, there was a big difference in UI outcomes between hospitals. Show less
In prostate (PCa) and colorectal (CRC) cancer, there is a need to improve patient stratification techniques that aid diagnostic and prognostic decision-making. To fulfill this unmet clinical need,... Show moreIn prostate (PCa) and colorectal (CRC) cancer, there is a need to improve patient stratification techniques that aid diagnostic and prognostic decision-making. To fulfill this unmet clinical need, the measurement of disease-related biological parameters known as “biomarkers” from biofluids is an approach with the potential to develop noninvasive tests as well as achieve greater clinical accuracy and personalized medicine. Thus, this thesis focused on developing a better understanding of biomarkers relevant to PCa and CRC as well as advancing analytical methodology and achieving methodological advancements for the purpose of biomarker discovery. In chapters two and three, a large diversity of prostate-specific antigen (PSA) cleaved and non-cleaved proteoforms (PCa) with different N-glycosylation patterns were determined in urine and seminal fluid using capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS), some of which are relevant for PCa patient stratification. In addition, the data processing workflow was improved in chapter three in order to enable larger studies of intact proteoforms to be performed. Furthermore, chapter four developed a reversed phase-liquid chromatography (RPLC)-MS method whereby it was possible to determine sialic acid linkages and positional isomers in released N-glycans following fluorescent labeling and sialic acid derivatization. This method was applied in chapter five to study serum N-glycosylation profiles in CRC and it was demonstrated that specific N-glycan isomers are implicated in the disease and differences between histological types were eradicated following surgery. 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
Dassen, M.G.; Janssen, T.; Kusters, M.; Pos, F.; Kerkmeijer, L.G.W.; Heide, U.A. van der; Bijl, E. van der 2023
PurposeTo quantify the difference in accuracy of adapt-to-position (ATP), adapt-to-rotation (ATR) and adapt-to-shape (ATS) workflows used in MRI-guided online adaptive radiotherapy for prostate... Show morePurposeTo quantify the difference in accuracy of adapt-to-position (ATP), adapt-to-rotation (ATR) and adapt-to-shape (ATS) workflows used in MRI-guided online adaptive radiotherapy for prostate carcinoma (PCa) by evaluating the margins required to accommodate intra-fraction motion of the clinical target volumes for prostate (CTVpros), prostate including seminal vesicles (CTVpros + sv) and gross tumor volume (GTV).Materials and methodsClinical delineations of the CTVpros, CTVpros + sv and GTV of 24 patients with intermediate- and high-risk PCa, treated using ATS on a 1.5 T MR-Linac, were used for analysis. Delineations were available pre- and during beam-on. To simulate ATP and ATR workflows, we automatically generated the structures associated with these workflows using rigid transformations from the planning-MRI to the daily online MRIs. Clinical GTVs were analyzed as ATR GTVs and only ATP GTVs were simulated. Planning target volumes (PTVs) were generated with isotropic margins ranging 0.0–5.0 mm. The volumetric overlap was calculated between these PTVs and their corresponding clinical delineation on the MRI acquired during beam-on and averaged over all treatment fractions.ResultsThe PTV margin required to cover > 95% of the CTVpros was equal (2.5 mm) for all workflows. For the CTVpros + sv, this margin increased to 5.0, 4.0 and 3.5 mm in the ATP, ATR and ATS workflow, respectively. GTV coverage improved from ATP to ATR for margins up to 4.0 mm.ConclusionATP, ATR and ATS workflows ensure equal coverage of the CTVpros for the current clinical margins. For the CTVpros + sv, ATS showed optimal performance. GTV coverage improves by additional adaptations to prostate rotations. Show less
Non-metastatic prostate cancer (PCa) patients are at increased risk for osteoporosis and fractures mainly due to androgen deprivation therapy (ADT)-associated hypogonadism, but this remains largely... Show moreNon-metastatic prostate cancer (PCa) patients are at increased risk for osteoporosis and fractures mainly due to androgen deprivation therapy (ADT)-associated hypogonadism, but this remains largely underdiagnosed and untreated. In this study, we examine the value of pre-screening calcaneal QUS in identifying patients who should be referred for screening for osteoporosis using dual-energy X-Ray absorptiometry (DXA). In a single-center retrospective cross-sectional cohort study, we analysed data on DXA and calcaneal QUS measurements systematically collected between 2011 and 2013 in all non-metastatic PCa patients attending our Uro-Oncological Clinic at the Leiden University Medical Center. Receiver operating characteristic curves were used to assess the positive (PPV) and negative (NPV) predictive values of QUS T-scores of 0, -1.0, and - 1.8 in identifying DXAdiagnosed osteoporosis (T-scores < - 2.5 and < -2) at lumbar spine and/or femoral neck. Complete sets of data were available in 256 patients, median age 70.9 (53.6-89.5) years; 93.0 % had received local treatment, 84.4 % with additional ADT. Prevalence of osteoporosis and osteopenia was respectively 10.5 % and 53 %. Mean QUS Tscore was -0.54 +/- 1.58. Whereas PPV at any QUS T-score was <25 %, precluding the use of QUS as surrogate for DXA in screening for osteoporosis, QUS T-scores of -1.0 to 0.0 had a NPV of >= 94.5 % for DXA T-scores < 2.5 and < -2 at any site, confidently identifying patients least likely to have osteoporosis, thereby significantly reducing the number of patients requiring DXA screening for diagnosing osteoporosis by up to two-third. Osteoporosis screening is a significant unmet need in non-metastatic prostate cancer patients treated with ADT, and QUS may represent a valuable alternative pre-screening strategy to overcome logistics, time demands, and economic barriers encountered with current strategies for osteoporosis screening in these patients. Summary: Osteoporosis and associated increased fracture risk are common in non-metastatic prostate carcinoma, mainly due to androgen deprivation therapy, but these often remain underdiagnosed and untreated. We demonstrate that QUS is a safe, less costly pre-screen tool that reduces by up to two-third the number of patients requiring referral for DXA for osteoporosis screening. Show less
Wit, E.M.K.; KleinJan, G.H.; Berrens, A.C.; Vliet, R. van; Leeuwen, P.J. van; Buckle, T.; ... ; Poel, H.G. van der 2023
ObjectiveTo determine the diagnostic accuracy of the hybrid tracer indocyanine green (ICG)-Technetium-99 m(Tc-99m)-nanocolloid compared to sequential tracers of Tc-99m-nanocolloid and free-ICG in... Show moreObjectiveTo determine the diagnostic accuracy of the hybrid tracer indocyanine green (ICG)-Technetium-99 m(Tc-99m)-nanocolloid compared to sequential tracers of Tc-99m-nanocolloid and free-ICG in detecting tumor-positive lymph nodes (LN) during primary surgery in prostate cancer (PCa) patients.IntroductionImage-guided surgery strategies can help visualize individual lymphatic drainage patterns and sentinel lymph nodes (SLNs) in PCa patients. For lymphatic mapping radioactive, fluorescent and hybrid tracers are being clinically exploited. In this prospective randomized phase II trial, we made a head-to-head comparison between ICG-Tc-99m-nanocolloid (hybrid group) and Tc-99m-nanocolloid and subsequent free-ICG injection (sequential group).MethodsPCa patients with a >5% risk of lymphatic involvement according to the 2012 Briganti nomogram and planned for prostatectomy were included and randomized (1:1) between ultrasound-guided intraprostatic tracer administration of ICG-Tc-99m-nanocolloid (n = 69) or Tc-99m-nanocolloid (n = 69) 5 h before surgery. Preoperative lymphoscintigraphy and SPECT/CT were performed to define the locations of the SLNs. Additionally, all participants in the sequential group received an injection of free-ICG at time of surgery. Subsequently, all (S)LNs were dissected using fluorescence guidance followed by an extended pelvic lymph node dissection (ePLND). The primary outcome was the total number of surgically removed (S)LNs and tumor-positive (S)LNs.ResultsThe total number of surgically removed (S)LN packages was 701 and 733 in the hybrid and sequential groups, respectively (p = 0.727). The total number of fluorescent LNs retrieved was 310 and 665 nodes in the hybrid and sequential groups, respectively (p < 0.001). However, no statistically significant difference was observed in the corresponding number of tumor-positive nodes among the groups (44 vs. 33; p = 0.470). Consequently, the rate of tumor-positive fluorescent LNs was higher in the hybrid group (7.4%) compared to the sequential group (2.6%; p = 0.002), indicating an enhanced positive predictive value for the hybrid approach. There was no difference in complications within 90 days after surgery (p = 0.78).ConclusionsThe hybrid tracer ICG-Tc-99m-nanocolloid improved the positive predictive value for tumor-bearing LNs while minimizing the number of fluorescent nodes compared to the sequential tracer approach. Consequently, the hybrid tracer ICG-Tc-99m-nanocolloid enables the most reliable and minimal invasive method for LN staging in PCa patients. Show less
Mehra, N.; Kloots, I.; Vlaming, M.; Aluwini, S.; Dewulf, E.; Oprea-Lager, D.E.; ... ; Ausems, M. 2023
Background: Germline and tumour genetic testing in prostate cancer (PCa) is becoming more broadly accepted, but testing indications and clinical consequences for carriers in each disease stage are... Show moreBackground: Germline and tumour genetic testing in prostate cancer (PCa) is becoming more broadly accepted, but testing indications and clinical consequences for carriers in each disease stage are not yet well defined.Objective: To determine the consensus of a Dutch multidisciplinary expert panel on the indication and application of germline and tumour genetic testing in PCa.Design, setting, and participants: The panel consisted of 39 specialists involved in PCa management. We used a modified Delphi method consisting of two voting rounds and a virtual consensus meeting.Outcome measurements and statistical analysis: Consensus was reached if >75% of the panellists chose the same option. Appropriateness was assessed by the RAND/UCLA appropriateness method.Results and limitations: Of the multiple-choice questions, 44% reached consensus. For men without PCa having a relevant family history (familial PCa/BRCA-related hered-itary cancer), follow-up by prostate-specific antigen was considered appropriate. For patients with low-risk localised PCa and a family history of PCa, active surveil-lance was considered appropriate, except in case of the patient being a BRCA2 germ -line pathogenic variant carrier. Germline and tumour genetic testing should not be done for nonmetastatic hormone-sensitive PCa in the absence of a relevant family history of cancer. Tumour genetic testing was deemed most appropriate for the identification of actionable variants, with uncertainty for germline testing. For tumour genetic testing in metastatic castration-resistant PCa, consensus was not reached for the timing and panel composition. The principal limitations are as fol-lows: (1) a number of topics discussed lack scientific evidence, and therefore the recommendations are partly opinion based, and (2) there was a small number of experts per discipline.Conclusions: The outcomes of this Dutch consensus meeting may provide further guidance on genetic counselling and molecular testing related to PCa.Patient summary: A group of Dutch specialists discussed the use of germline and tumour genetic testing in prostate cancer (PCa) patients, indication of these tests (which patients and when), and impact of these tests on the management and treatment of PCa.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of European Association of Urology. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4.0/). Show less
The work included in this thesis is aimed at developing novel tools to advance our understanding of prostate cancer. The clinical problem of prostate cancer is presented and discussed in the wider... Show moreThe work included in this thesis is aimed at developing novel tools to advance our understanding of prostate cancer. The clinical problem of prostate cancer is presented and discussed in the wider context of the current clinical knowledge, highlighting the genetic mechanisms at its base. A dedicated chapter focuses on bone metastases, highly morbid feature of advanced prostate cancer, discussing the known mechanisms and the available models to study it in translational research. Then, moving from the molecular analysis of clinical specimens of bone metastasis, a biochemical pathway is identified and further studied in vitro, ex vivo and in vivo, validating the initial findings. A novel, early-stage prostate cancer patient-derived xenograft is presented and extensively characterized and implemented in a drug screening. This allowed to screen the effect of over 70 known drugs on prostate cancer models, using three-dimensional cultures and a semi-automated platform. As all research builds on previously established findings, a bibliometric analysis tool is presented, to assist in the generation of a knowledge network arranged by topic and impact of research. All these aspects and findings are then discussed in the context of the current direction of prostate cancer research, its emerging tools and its long-known challenges. 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
In the past decade it became increasingly clear that tumor heterogeneity represents one of the major problems for cancer treatment, also in prostate cancer. The identification of the molecular... Show moreIn the past decade it became increasingly clear that tumor heterogeneity represents one of the major problems for cancer treatment, also in prostate cancer. The identification of the molecular properties of highly aggressive cells (Cancer Stem Cells, CSCs) dispersed within the tumor represents a challenge for the identification of new efficient therapies. In most of the cases, current treatments are indeed successful in eradicating the primary tumor. However, the clinical evidence of relapse and the occurrence of therapy resistance, suggest the presence of subpopulation of cells within the tumor, that can survive such treatments and can perpetuate the cancer. In this thesis we investigated the molecular properties of selected highly aggressive CSCs and indentified novel modulators responsible for the maintenance of their aggressive behavior. Collectively, the studies described in this thesis have increased our insights into the molecular properties of highly metastatic and tumorigenic prostate cancer stem-like cells and provided new targets for possible diagnostic and therapeutic applications. Show less
Cancer and fibrosis are devastating diseases of high mortality rate and with limited curative therapies available. A better understanding of the biological drivers of these diseases is fundamental... Show moreCancer and fibrosis are devastating diseases of high mortality rate and with limited curative therapies available. A better understanding of the biological drivers of these diseases is fundamental in order to develop effective therapeutics. At the molecular level, signaling pathways control cell growth, differentiation or apoptosis during development and adult life of the organism ensuring homeostasis. Paradoxically, the same signals are often implicated or even drive disease progression. One of the signaling pathways with key regulatory functions in homeostasis, tissue fibrosis and cancer in many organs is the TGFβ/BMP pathway. In this thesis we addressed the role and therapeutic potential of TGFβ/BMP pathway inhibition using different drug compounds that are currently towards the clinic or being tested in clinical trials. Three distinct types of inhibitors were used; small molecule inhibitors of the ALK4, 5 and 7 TGFβ receptor kinases, an antisense oligonucleotide interfering with ALK5 mRNA splicing and an ALK1 ligand trap; a peptide that contains the extracellular domain of ALK1 fused to Fc and sequesters BMP9 and BMP10. These inhibitors were used in an ex vivo human fibrosis model and in vivo mouse models of various human diseases (acute liver failure/ liver regeneration, Dupuytren's fibrosis) and cancer (prostate, liver). Show less
We have developed novel fluorescence bio-imaging based automated models to screen for novel candidate targets involved in prostate cancer metastasis. Utilizing these models and adopting a... Show moreWe have developed novel fluorescence bio-imaging based automated models to screen for novel candidate targets involved in prostate cancer metastasis. Utilizing these models and adopting a functional genomics based approach; we identified SYK as a novel regulator of prostate cancer progression. We also identified functional involvement of MST1R in regulating the progression of prostate cancer. For both of these targets, there is supporting human clinical data to validate our results in prostate cancer. Show less
The aim of this work was to develop methods to measure structural changes in the skeleton using MicroCT. In addition, these new methods should be able to quantify biologically relevant changes. In... Show moreThe aim of this work was to develop methods to measure structural changes in the skeleton using MicroCT. In addition, these new methods should be able to quantify biologically relevant changes. In order to do this, normalized methods to analyse MicroCT scans and perform quantitative measurements within these datasets are described in this thesis. These techniques were combined with a biological angiogenesis assay and used as research tools in a study comparing various different combination treatments of bone metastases. 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
The skeleton is one of the most common organs to be affected by metastatic disease. However, only a restricted number of solid cancers, especially those of the breast and prostate, are responsible... Show moreThe skeleton is one of the most common organs to be affected by metastatic disease. However, only a restricted number of solid cancers, especially those of the breast and prostate, are responsible for the majority of the bone metastases. Bone metastases are a major cause of morbidity, characterized by severe pain and high incidence of fractures, spinal cord compression and bone marrow aplasia requiring hospitalization. Despite the high frequency of skeletal metastases, the molecular mechanisms underlying the predisposition for tumors to colonize bone are poorly understood and treatment options are often unsatisfactory. The focus of this thesis was to better understand the processes that contribute to the formation of distant metastasis (chapter 2), particularly to bone (chapter 4__7), as well as to explore new treatment strategies with conventional (chapter 4 and 5) and novel therapeutic molecules (chapter 6 and 7) using optical imaging to sensitively monitor growth, dissemination and metastasis in mouse models (chapter 3__7). Show less
