The dissertation is focused on the study of intercellular interactions in skin tumors. It is based on 5 original publications that cover several topics. We studied the origin of tumor-associated fibroblasts concerning the primary tumor population. We demonstrated using a mouse model that tumor-associated fibroblasts are produced from the host organism and thus did not arise from transformation directly from tumor cells. We also investigated the relationship between tumor-associated fibroblasts and keratinocytes. We have shown that tumor-associated melanoma fibroblasts affect keratinocytes which, under their influence, acquire the features typically observed in migrating cells and cells undergoing epithelial-mesenchymal transition. We studied the interactions between healthy fibroblasts and tumor cells. We have demonstrated that fibroblasts acquired from healthy skin from a patient suffering from melanoma are significantly different from control fibroblasts of healthy donors in the expression profile. Changes in distal fibroblasts support the view of melanoma as a systemic disease. We have further demonstrated that melanoma-associated fibroblasts do not carry a BRAF mutation, in contrast to BRAF positivity of melanoma cells. And therefore, they did not arise from the transition from melanoma. The...

Die Entwicklung der neuen Systemtherapien führte in den letzten Jahren zu einer bedeutenden Verbesserung des Langzeitüberlebens bei Patienten mit metastasiertem Melanom. Die verschiedenen Therapieoptionen mit ihren entsprechenden jeweiligen Toxizitäten sowie die Unterschiede im Therapieansprechen auf die differenten Therapieformen machen es erforderlich, anhand von prädiktiven Faktoren und Biomarkern Therapieentscheidungen zu treffen, um individuell die beste Therapie für den Patienten auszuwählen. Die Tumorwachstumskinetik wird dabei immer wieder als relevanter Faktor genannt. Ihr genauer Einfluss sowie die genaue Definition einer schnellen Tumorkinetik ist jedoch bis heute nicht klar definiert. Diese Arbeit soll dazu beitragen, die prognostische Wertigkeit der Metastasenwachstumsrate (MGR) als prädiktiven Marker vor dem Start einer Systemtherapie zu untersuchen. Konkret soll die Hypothese geprüft werden, ob eine schnelle MGR vor Therapiebeginn einen negativen Einfluss auf das Therapieansprechen sowie das klinische Outcome hat. Vor diesem Hintergrund wurde retrospektiv ein Patientenkollektiv von insgesamt 115 Patienten, aufgeteilt in drei Kohorten (Monotherapie mit PD-1-Antikörpern: n = 33, Kombinationstherapie mit PD-1- und CTLA-4-Antikörpern: n = 34, zielgerichtete Therapie mit BRAF- +/- MEK-Inhibitoren: n = 48), untersucht. Die Erhebung der Dresdner Daten war dabei Teil eines Verbundprojekts mit 12 teilnehmenden Kliniken, sodass zusätzlich zur Dresdner Auswertung für die Monotherapie aus PD-1-Antikörpern auch eine multizentrische Gesamtanalyse der Daten stattfinden konnte. Für die Datenerhebung wurden alle Patienten in Betracht gezogen, die seit Zulassung der einzelnen Therapieformen aufgrund eines kutanen, uvealen, mucosalen oder okkulten Melanoms im Stadium IIIB oder höher am Universitätsklinikum Dresden mit einer entsprechenden Systemtherapie behandelt wurden und eine messbare Metastasierung (CT/MRT/PET-CT) im Baseline-Staging sowie einem Pre-Baseline-Staging aufwiesen. Bei fehlenden Follow-Up-Daten sowie einer adjuvanten Therapiesituation wurden die Patienten aus der Datenerhebung ausgeschlossen. Die MGR wurde für den Zeitraum zwischen Pre-Baseline-Staging und dem Baseline-Staging bestimmt. Mittels Kaplan-Meier-Überlebenskurven sowie univariater und multivariater Cox-Regression wurde der prognostische Einfluss der MGR analysiert. Die Untersuchung des Einflusses der MGR auf das Therapieansprechen erfolgte mithilfe des Fisher-Tests und des Mann-Whitney-U-Tests. In der Dresdner Studie war eine hohe MGR (>3,9 mm/Monat) mit einem signifikant schlechteren progressionsfreien Überleben (PFS) für Patienten unter einer zielgerichteten Therapie verbunden. Zusätzlich zeigten diese Patienten ein signifikant schlechteres Ansprechen auf die Therapie mit BRAF- und MEK-Inhibitoren, im Vergleich zu Patienten, die eine MGR < 3,9 mm/Monat aufwiesen. Für das Gesamtüberleben (OS) zeigte sich trotz geringer Fallzahl sowohl in der Kohorte der zielgerichteten Therapie als auch in der Kohorte der kombinierten Immuntherapie mit Ipilimumab und Nivolumab ein Trend zu einem kürzeren OS, wenn eine hohe MGR vorlag. Dieser Trend konnte für die kombinierte Immuntherapie zusätzlich auch für das PFS festgestellt werden. Für die PD-1-Antikörper-Monotherapie konnte anhand der Dresdner Daten kein signifikanter Unterschied für das OS und PFS zwischen Patienten mit niedriger und hoher MGR festgestellt werden. In der Gesamtbetrachtung stellt die MGR einen prognostischen Marker für Patienten unter einer zielgerichteten Therapie mit BRAF- und MEK-Inhibitoren sowie in Zusammenschau mit den Ergebnissen der Gesamtstudie auch für Patienten unter einer PD-1-Antikörper-Monotherapie dar. Zusätzlich ergaben sich innerhalb dieser Arbeit Hinweise darauf, dass dies auch für die Immunkombinationstherapie mit Ipilimumab und Nivolumab zutrifft. Um die prognostische Wertigkeit der MGR für die unterschiedlichen Systemtherapien gleichermaßen beurteilen zu können, sind weitere Untersuchungen an größeren Patientenkollektiven notwendig. / The development of new system therapies has resulted in an important improvement in the long term survival of patients with a metastatic melanoma. Different therapy options with their respective individual toxicity, as well as differences in the reactions to different forms of therapy, require therapeutic decisions on the basis of predictive factors and bio markers in order to choose individually the best therapy for the patient. Tumor growth kinetics is often considered to be a relevant factor. Its specific influence as well as the exact definition of fast tumor kinetics has, however, not yet been clearly defined. This paper is supposed to support the examination of the prognostic value of the metastatic growth rate (MGR) as a predictive marker before a system therapy is introduced. The hypothesis that a fast MGR before a therapy begins has a negative influence on the therapy response and the clinical outcome has to be examined. On the basis of this hypothesis a patient collective of 115 patients in total, divided into three cohorts (mono therapy with PD-1-antibodies: n=33, combination therapy of PD-1- and CTLA-4-antibodies: n=34, target-orientated therapy with BRAF- t/- MEK inhibitors: n=48) was examined retrospectively. The collection of the Dresden data was part of a cooperative project of 12 participating clinics resulting in a multi-centric overall analysis of the data in addition to the Dresden evaluation of the mono therapy of PD1-antibodies. For the collection of the data those patients were considered who had been treated at Dresden university hospital since the approval of their individual form of therapy with a respective system therapy because of a cutaneous, uveal, mucosal or occult melanoma stage IIIB or higher and who showed a measurable metastasis (CT/MRT/PET-CT) in baseline staging as well as in pre-baseline staging. Patients without any follow-up data and an adjuvant therapy were excluded from the collection of data. The MGR was fixed for the timespan between pre-baseline staging and baseline staging. The prognostic influence of the MGR was analysed by means of the Kaplan-Meier-survival curve as well as univariate and multivariate cox regression. The study of the influence of MGR on the therapy response was based on the Fisher-Tests and the Mann-Whitney-U-Tests. The Dresden study showed the correlation between a high MGR (>3,9 mm/month) and a significantly worse progression free survival (PFS) for patients having a target-orientated therapy. Additionally, those patients showed a significantly weaker reaction to the therapy with BRAF - and MEK-inhibitors in comparison to patients who had an MGR < 3,9mm/month. Considering the overall survival (OS) of those with a fast MGR a trend to a shorter OS could be established, in spite of low case numbers in the cohort of the target-orientated therapy as well as in the cohort of the combined immune therapy with Ipilimumab and Nivolumab. This trend could be found for the combined immune therapy as well as for the PFS. Referring to the anti-PD1- mono therapy no significant difference could be found for the OS and the PFS between patients with faster and slower MGR. In the overall view the MGR proves to be a prognostic marker for patients having a target-orientated therapy with BRAF- and MEK-inhibitors and, also looking at the results of the overall study, for patients having a PD-1- antibody mono therapy. Additionally, this study revealed a significant indication that this also applies to the immune combination therapy of Ipilimumab and Nivolumab. Further studies with larger collectives of patients are necessary to be able to likewise judge the different prognostic valency of the MGR for the different system therapies.

Melanoma is a life threatening type of skin cancer with numerous fatal incidences all over the world. The 5-year survival rate is very high for cases that are diagnosed in early stage. So, early detection of melanoma is of vital importance. Except for several techniques that clinicians apply so as to improve the reliability of detecting melanoma, many automated algorithms and mobile applications have been developed for the same purpose.In this paper, deep learning model designed from scratch as well as the pretrained models Inception v3 and VGG-16 are used with the aim of developing a reliable tool that can be used for melanoma detection by clinicians and individual users. Dermatologists who use dermoscopes can take advantage of the algorithms trained on dermoscopical images and acquire a confirmation about their diagnosis. On the other hand, the models trained on clinical images can be used on mobile applications, since a cell phone camera takes images similar to them.The results using Inception v3 model for dermoscopical images achieved accuracy 91.4%, sensitivity 87.8% and specificity 92.3%. For clinical images, the VGG-16 model achieved accuracy 86.3%, sensitivity 84.5% and specificity 88.8%. The results are compared to those of clinicians, which shows that the algorithms can be used reliably for the detection of melanoma.

Omi/HtrA2 is a mitochondrial serine protease that is known to translocate to the cytoplasm upon induction of apoptosis and to activate caspase-dependent and caspase-independent cell death. The molecular mechanism of Omi/HtrA2's function is not clear but involves degradation of specific substrates. These substrates include cytoplasmic, mitochondrial, as well as nuclear proteins. We have isolated a new Omi/HtrA2 interactor, the THAP5 protein. THAP5 is a fifth member of a large family of transcription factors that are involved in cell proliferation, apoptosis, cell cycle control, chromosome segregation, chromatin modification and transcriptional regulation. THAP5 is an approximately 50kDa nuclear protein, with a restricted pattern of expression. Furthermore, there is no mouse or rat homolog for this protein. THAP5 mRNA is highly expressed in the human heart but some expression is also seen in the brain and skeletal muscle. The normal function of THAP5 in the heart or heart disease is unknown. THAP5 protein level is significantly reduced in the myocardial infarction (MI) area in the heart of patients with coronary artery disease (CAD). This part of the heart sustains most of the cellular damage and apoptosis. Our data clearly show that THAP5 is a specific substrate of the proapoptotic Omi/HtrA2 protease and is cleaved and removed during cell death. The molecular mechanism of THAP5's function is unclear. THAP5 can bind to a specific DNA sequence and repress transcription of a reporter gene. Our work suggests that THAP5 is a tissue specific transcriptional repressor that plays an important role in the normal function of the human heart as well as in the development of heart disease.

Patients with classical vitiligo lose partially their protecting inherited pigment. The cause of the disease is still unknown. Despite massive epidermal oxidative / nitrative stress and signs for DNA-damage in the skin and in the plasma, these patients have no higher prevalence for sun induced non-melanoma skin cancer and increased photo-damage. Protection and DNA-repair have been attributed to a functioning up-regulated wild type p53 / p21 cascade in association with up-regulated p76 MDM2. As some patients with cutaneous melanoma develop depigmentations away from their primary tumour site post surgical excision, it became of our interest, whether this melanoma associated leucoderma (MAL) is the same as classical vitiligo. The purpose of this thesis was two-fold. In part I, we wanted to further substantiate the reasons behind the constantly up-regulated wild-type functioning p53 / p21 cascade in classical vitiligo utilising a panel of proteins with direct and / or indirect action on p53 regulation, including p21, p76MDM2, MDM4/MDM4phospho, SPARC, VEGF-A and TGF-β1. In part II, we wanted to characterize MAL and compare this peculiar leucoderma with classical vitiligo using the same protein panel and methodologies. To achieve our goals, we used in vivo FT-Raman spectroscopy, in vitro cell cultures, in vitro and in situ immuno-fluorescence labelling, Western blot, dot blot and computer modelling techniques. Our data showed distinct differences between classical vitiligo and MAL. Our results in MAL exhibited a concentration dependent protein expression gradient between the basal / suprabasl layers and the upper layers of the epidermal compartment using catalase, ONOO-, p53, p21, MDM4, p76MDM2, TGF-β1 and VEGF-A expression gradient. Moreover, we document for the first time the presence of a nitrated non-fuctional SPARC protein in classical vitiligo which is absent in MAL. Although we show in vivo considerable ROS / RNS- mediated stress in MAL and classical vitiligo documented by FT-Raman spectroscopy, Western blot and in situ immuno-fluorescence, our results prove that MAL and classical vitiligo are two distinct entities.

Background: Development of brain metastases in advanced melanoma patients is a frequent event that limits patients’ quality of life and survival. Despite recent insights into melanoma genetics, systematic analyses of genetic alterations in melanoma brain metastasis formation are lacking. Moreover, whether brain metastases harbor distinct genetic alterations beyond those observed at different anatomic sites of the same patient remains unknown. Experimental Design and Results: In our study, 54 intracranial and 18 corresponding extracranial melanoma metastases were analyzed for mutations using targeted next generation sequencing of 29 recurrently mutated driver genes in melanoma. In 11 of 16 paired samples, we detected nucleotide modifications in brain metastases that were absent in matched metastases at extracranial sites. Moreover, we identified novel genetic variants in ARID1A, ARID2, SMARCA4 and BAP1, genes that have not been linked to brain metastases before; albeit most frequent mutations were found in ARID1A, ARID2 and BRAF. Conclusion: Our data provide new insights into the genetic landscape of intracranial melanoma metastases supporting a branched evolution model of metastasis formation.

No description available.

Melanoma is a highly malignant neoplasia with high rates of metastasis in humans and dogs. Regardless of being considered a highly immunogenic neoplasm, the function of the immune system is hampered by the expression of immune checkpoint molecules by the cancer cells. In contrast, soft tissue sarcomas are poorly immunogenic, as Tumor infiltrating Lymphocytes are lacking, or when present they are usually at the periphery of the tumor. Still, soft tissue sarcomas are considered immunosuppressed. Checkpoint molecules from the PD-axis are overexpressed in numerous human malignant neoplasia and have recently gained attention with a few reports in canine tumors. Immunotherapies against these checkpoint molecules have shown great efficacy in humans, but in order to determine translational approaches into canine patients, more research is needed. Here we determined the gene expression of Programed Death receptor-1, and its ligands PD-L1 and PD-L2 in canine tumors with two distinct immune profiles. Our results show that regardless of their immune profiles, melanoma versus soft tissue sarcoma, checkpoint molecules expression was higher in malignant tumors with a higher grade. Additionally, we evaluated the expression of these molecules in a set of patients that received histotripsy, which is a non-invasive and non-thermal ultrasound focused therapy that induces mechanical stress to the cells, leading to liquefactive necrosis. Here we reported a focal decrease of the expression of these checkpoint molecules in tissue sections obtain at the treatment interface, compared to those taken from untreated areas of the tumor. In addition, a positive relationship was noticed between the infiltration of CD3+ T lymphocytes and the expression of these checkpoint molecules in both canine melanoma, and soft tissue sarcoma. Our findings demonstrate that immunotherapies targeting these checkpoint molecules have a great potential for efficacy in canine neoplasia, along or combined with tumor ablation therapies that increased immune cell infiltration in poorly immunogenic neoplasia. / Doctor of Philosophy / Melanoma is a highly malignant tumor and very resistant to therapy for humans and dogs. At the same time, this neoplasia is usually highly infiltrated by cells from the immune system. However, this immune infiltration is often inhibited by molecules expressed by the melanoma cells. In contrast, soft tissue sarcoma is considered poorly immunogenic, as they often contain low levels of immune cell infiltrates but are still considered immune suppressed. In this study, we determined the expression of molecules that inhibit the effect of T lymphocytes, specifically Programed cell death receptor-1, PD-Ligand 1, and PD-Ligand 2 for these neoplasms with distinct immune profiles. We encounter that despite their immune profiles, the expression of these molecules is higher in malignant tumors. Additionally, we evaluated the expression of these molecules in a set of patients that received histotripsy, which is a non-invasive and non-thermal focused ultrasound therapy that induces mechanical stress to the cancerigenous cells, leading to its death (necrosis). Here we reported a focal decrease of the expression of these checkpoint molecules in tissue sections obtain at the treatment interface, compared to those taken from untreated areas of the tumor. In addition, a positive relationship was noticed between the infiltration of T lymphocytes and the expression of these checkpoint molecules in both canine melanoma, and soft tissue sarcoma. Our findings demonstrate that immunotherapies targeting these checkpoint molecules have a great potential for efficacy in canine neoplasms, along or combined with tumor ablation therapies that increased immune cell infiltration in poorly immunogenic neoplasia.

[ES] Esta tesis doctoral titulada "Evaluación preclínica de estrategias basadas en la senescencia para mejorar la terapia contra el cáncer" se centra en explotar la senescencia como opción terapéutica en los tratamientos contra el cáncer mediante el diseño, la síntesis y la evaluación in vitro e in vivo de varios nanodispositivos y profármacos, así como la identificación de un nuevo fármaco senolítico. En el primer capítulo experimental evaluamos el efecto negativo de la senescencia endotelial en el contexto tumoral y la consecuencia de su eliminación mediante el uso del senolítico navitoclax. Comprobamos que el tratamiento sistémico con palbociclib en un modelo ortotópico de cáncer de mama en ratones induce senescencia en las células endoteliales vasculares, generando un endotelio alterado funcionalmente que favorece la migración de células cancerosas. La recuperación de la funcionalidad endotelial se consigue con una estrategia terapéutica que, tras la inducción de senescencia con palbociclib, elimina las células senescentes (senólisis) con la nanopartícula (NP(nav)-Gal). En el modelo preclínico, el tratamiento combinado de palbociclib con NP(nav)-Gal disminuyó la senescencia endotelial en venas, así como los nódulos metastásicos en los pulmones. Teniendo en cuenta los resultados obtenidos, el capítulo dos se describe una estrategia terapéutica en dos pasos similar a la anterior para cáncer de mama triple negativo. En este caso se emplea un modelo de ratón implantado con xenoinjertos humanos de este tipo de cáncer para evaluar el efecto de la terapia combinada de palbociclib y navitoclax. Para superar los efectos secundarios del tratamiento con navitoclax (principalmente trombocitopenia), evaluamos el efecto del profármaco nav-Gal. La senescencia inducida por la terapia con palbociclib, seguida de una terapia adyuvante con navitoclax o nav-Gal, provoca la eliminación sinérgica de las células senescentes tumorales y la reducción del crecimiento tumoral y de la metástasis pulmonar en el modelo utilizado de ratones con xenoinjertos de cáncer de mama humano agresivo. El capítulo tres se centra en el diseño y el desarrollo de un nuevo sistema de comunicación de nanopartículas por estigmergía para mejorar la terapia tumoral en el cáncer de mama. La comunicación de nanopartículas por estigmergía consiste en un sistema secuencial de dos nanopartículas en la que la primera modifica el entorno permitiendo que la segunda nanopartícula pueda actuar. Para ello, nos basamos de nuevo en una terapia en dos pasos, siendo el primer paso la inducción de senescencia con palbociclib en las células tumores y el segundo su posterior eliminación con navitoclax. Con este objetivo, se prepararon dos nanodispositivos: el primer nanodispositivo (NP(palbo)PEG-MUC1) se cargó con palbociclib y se funcionalizó con un aptámero dirigido a la proteína de superficie MUC1, frecuentemente sobreexpresada en las células tumorales de mama; para el segundo nanodispositivo se empleó la nanopartícula senolítica NP(nav)-Gal. Cuando ambas nanopartículas se administraron secuencialmente se consiguió un efecto aumentado, retrasando el crecimiento tumoral y reduciendo las metástasis en pulmón en el modelo descrito previamente de ratones con xenoinjerto hTNBC. En el último capítulo identificamos un nuevo agente senolítico (H14) que puede eliminar a las células tumorales senescentes de melanoma con una eficacia y seguridad óptima in vivo. Para ello, se realizó un cribado de una biblioteca combinatoria de hexapéptidos de D-aminoácidos en células senescentes de melanoma SK-Mel-103, en las que la inducción de la senescencia se había producido mediante el tratamiento con palbociclib. El tratamiento combinado de palbociclib y el hexapéptido H14 logró una mejora en la eliminación de células tumorales senescentes in vivo, así como en la reducción del crecimiento tumoral, alcanzando efectos similares al tratamiento combinado de palbociclib con navitoclax. / [CA] Aquesta tesi doctoral titulada "Avaluació preclínica d'estratègies basades en la senescència per millorar la teràpia contra el càncer" se centra a explotar la senescència com a opció terapèutica en els tractaments contra el càncer mitjançant el disseny, la síntesi i l'avaluació in vitro i in vivo diversos nanodispositius i profàrmacs, així com la identificació d'un nou fàrmac senolític. Al primer capítol experimental avaluem l'efecte negatiu de la senescència endotelial en el context tumoral i la conseqüència de la seva eliminació mitjançant l'ús del senolític navitoclax. Comprovem que el tractament sistèmic amb palbociclib en un model ortotòpic de càncer de mama en ratolins indueix senescència a les cèl·lules endotelials vasculars, generant un endoteli alterat funcionalment que afavoreix la migració de cèl·lules canceroses. La recuperació de la funcionalitat endotelial s'aconsegueix amb una estratègia terapèutica que, després de la inducció de senescència amb palbociclib, elimina les cèl·lules senescents (senòlisi) amb la nanopartícula (NP(nav)-Gal). En el model preclínic, el tractament combinat de palbociclib amb NP(nav)-Gal va disminuir la senescència endotelial en venes, així com els nòduls metastàsics als pulmons. Tenint en compte els resultats obtinguts, el capítol dos es descriu una estratègia terapèutica en dos passos similar a l'anterior per al càncer de mama triple negatiu. En aquest cas es fa servir un model de ratolí implantat amb xenoempelts humans d'aquest tipus de càncer per avaluar l'efecte de la teràpia combinada de palbociclib i navitoclax. Per superar els efectes secundaris del tractament amb navitoclax (principalment trombocitopènia), avaluem l'efecte del profàrmac nav-Gal. La senescència induïda per la teràpia amb palbociclib, seguida d'una teràpia adjuvant amb navitoclax o nav-Gal, provoca l'eliminació sinèrgica de les cèl·lules senescents tumorals i la reducció del creixement tumoral i de la metàstasi pulmonar en el model utilitzat de ratolins amb xenoempelts de càncer de mama humà agressiu. El capítol tres se centra en el disseny i desenvolupament d'un nou sistema de comunicació de nanopartícules per estigmergia per millorar la teràpia tumoral al càncer de mama. La comunicació de nanopartícules per estigmergia consisteix en un sistema seqüencial de dues nanopartícules on la primera modifica l'entorn permetent que la segona nanopartícula pugui actuar. Per això, ens basem de nou en una teràpia en dos passos, sent el primer pas la inducció de senescència amb palbociclib a les cèl·lules tumors i el segon la posterior eliminació amb navitoclax. Amb aquest objectiu, es van preparar dos nanodispositius: el primer nanodispositiu (NP(palbo)PEG-MUC1) es va carregar amb palbociclib i es va funcionalitzar amb un aptàmer dirigit a la proteïna de superfície MUC1, freqüentment sobreexpressada a les cèl·lules tumorals de mama; per al segon nanodispositiu es va emprar la nanopartícula senolítica NP(nav)-Gal. Quan ambdues nanopartícules es van administrar seqüencialment es va aconseguir un efecte augmentat, endarrerint el creixement tumoral i reduint les metàstasis en pulmó en el model descrit prèviament de ratolins amb xenoempelt hTNBC. A l'últim capítol identifiquem un nou agent senolític (H14) que pot eliminar les cèl·lules tumorals senescents de melanoma amb una eficàcia i seguretat òptima in vivo. Per fer-ho, es va realitzar un cribratge d'una biblioteca combinatòria d'hexapèptids de D-aminoàcids en cèl·lules senescents de melanoma SK-Mel-103, on la inducció de la senescència s'havia produït mitjançant el tractament amb palbociclib. El tractament combinat de palbociclib i l'hexapèptid H14 va aconseguir una millora en l'eliminació de cèl·lules tumorals senescents in vivo, així com en la reducció del creixement tumoral, aconseguint efectes similars al tractament combinat de palbociclib amb navitoclax. / [EN] This PhD thesis entitled "Preclinical evaluation of senescence-based strategies to improve cancer therapy" focuses on exploiting senescence as a therapeutic option in cancer treatments through design, synthesis and in vitro and in vivo evaluation. of several nanodevices and prodrugs, as well as the identification of a new senolytic drug. In the first experimental chapter we evaluated the negative effect of endothelial senescence in the tumor context and the consequence of its elimination through the use of the senolytic navitoclax. We found that systemic treatment with palbociclib in an orthotopic model of breast cancer in mice induces senescence in vascular endothelial cells, generating a altered endothelium that favors the migration of cancer cells. Recovery of endothelial functionality was achieved, after palbociclib-senescence induction, by removal of senescent cells (senolysis) with navitoclax-loaded nanoparticles (NP(nav)-Gal). In a preclinical model, the combined treatment of palbociclib with NP(nav)-Gal decreased endothelial senescence in veins as well as in metastatic nodules in the lungs. Taking into account the results obtained, chapter two describes a similar therapeutic strategy for triple-negative breast cancer. In this case, a human xenograft mice model was employed to evaluate the effect of combined therapy of palbociclib plus navitoclax. To overcome the side effects of navitoclax treatment (mainly thrombocytopenia), we evaluated the effect of the prodrug nav-Gal. Palbociclib therapy-induced senescence, followed by adjuvant navitoclax or nav-Gal therapy, resulted in synergistic clearance of senescent tumor cells and reduction of tumor growth and lung metastasis in the xenograft mice model of aggressive human TNBC. Chapter three focuses on the design and development of a new stigmergy nanoparticle communication system to improve tumor therapy in breast cancer. The communication of nanoparticles by stigmergy consists of a sequential system of two nanoparticles in which the first modifies the environment allowing the second nanoparticle to act. To do this, we again rely on a two-step therapy, the first step being the induction of senescence with palbociclib in tumor cells and the second its subsequent elimination with navitoclax. To this end, two nanodevices were prepared: the first nanodevice (NP(palbo)PEG-MUC1) was loaded with palbociclib and functionalized with an aptamer targeting the surface protein MUC1, frequently overexpressed in breast tumor cells; for the second nanodevice, the senolytic nanoparticle NP(nav)-Gal was used. When both nanoparticles were administered sequentially, an increased effect was achieved, delaying tumor growth and reducing lung metastases in the previously described model of hTNBC xenograft mice. In the last chapter we identified a new senolytic agent (H14) that can kill senescent melanoma tumor cells with optimal efficacy and safety in vivo. For this, a combinatorial library of D-amino acid hexapeptides was screened in senescent SK-Mel-103 melanoma cells, in which senescence induction had occurred by treatment with palbociclib. The combined treatment of palbociclib and H14 hexapeptide achieved an improvement in the elimination of senescent tumor cells in vivo, as well as in the reduction of tumor growth, reaching similar effects to the combined treatment of palbociclib and navitoclax. Future breakthroughs in the field of cellular senescence treatment are expected. We hope that the results achieved in this PhD thesis will open new research opportunities and inspire the development of advanced strategies with smart nanodevices and prodrugs for their application in the field of cellular senescence and other different biomedical areas and in sensing and communication technologies to solve patient needs. / Estepa Fernández, A. (2022). Preclinical evaluation of senescence-based strategies to improve cancer therapy [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/188845

No / Oncolytic viruses (OV) are promising treatments for cancer, with several currently undergoing testing in randomised clinical trials. Measles virus (MV) has not yet been tested in models of human melanoma. This study demonstrates the efficacy of MV against human melanoma. It is increasingly recognised that an essential component of therapy with OV is the recruitment of host antitumour immune responses, both innate and adaptive. MV-mediated melanoma cell death is an inflammatory process, causing the release of inflammatory cytokines including type-1 interferons and the potent danger signal HMGB1. Here, using human in vitro models, we demonstrate that MV enhances innate antitumour activity, and that MV-mediated melanoma cell death is capable of stimulating a melanoma-specific adaptive immune response.