L’espérance de vie des patients atteints de mélanome à haut risque ne peut être prédite d’une façon<p>fiable en se basant sur les analyses d’histopathologies de la lésion primitive et est souvent ajustée<p>durant la progression de la maladie. Notre étude vise à élargir nos observations initiales au niveau<p>des métastases cutanées et d’évaluer la valeur pronostique de tyrosinase related protein 1 (TYRP1)<p>dans les métastases ganglionnaires des patients atteints de mélanome de stades III et IV. TYRP1 est<p>une enzyme mélanosomale qui partage des similitudes structurelles avec la tyrosinase, l'enzyme clé<p>de la mélanogenèse.<p>L’expression de l'ARNm de TYRP1 a été quantifiée dans 104 métastases ganglionnaires par PCR<p>en temps réel et normalisée par rapport à l’expression de l’ARNm de S100B (marqueur reconnu du<p>mélanome) pour corriger l’expression de TYRP1 suivant la charge tumorale de l’échantillon. Le<p>rapport TYRP1/S100B a été calculé et la médiane a été utilisée en tant que valeur seuil. Ensuite<p>nous avons étudié la relation entre les valeurs de TYRP1/S100B, le suivi clinique et les<p>caractéristiques histopathologiques de la tumeur primitive.<p>Un rapport élevé de l’ARNm TYRP1/S100B corrélait significativement avec une survie sans<p>récidive et une survie globale plus courtes, avec une épaisseur de Breslow plus élevée et avec la<p>présence d'une ulcération au niveau de la tumeur primitive. En outre, une expression élevée de<p>TYRP1/S100B était de meilleure valeur pronostique pour la survie globale que l'épaisseur de<p>Breslow et l'ulcération des primitifs. De plus, cette expression est bien conservée au cours de la<p>progression de la maladie par rapport aux groupes de TYRP1 bas/élevé.<p>Nous avons constaté qu’une expression élevée de TYRP1/S100B dans les métastases de patients<p>atteints de mélanome est associée à un résultat clinique défavorable et une survie courte. Menée sur<p>des patients atteints d'un mélanome à haut risque de récidive, cette première étude a suggéré que<p>l'ARNm de TYRP1 dans les métastases pourrait servir de biomarqueur pour affiner le pronostic<p>initial des patients surtout ceux ayant des lésions primitives de localisation inconnues ou non<p>évaluables et peut permettre une gestion différente des deux groupes de patients. Son expression<p>conservée au cours de la progression de la maladie est en faveur de son utilisation comme cible<p>thérapeutique.<p>En second lieu, en évaluant l’expression de la protéine TYRP1 par immunohistochimie dans les<p>métastases cutanées et ganglionnaires, nous avons observé qu’elle n'était pas détectée dans la moitié <p>7<p>des tissus exprimant bel et bien l'ARNm correspondant et qu’elle, contrairement à l'ARNm, n’était<p>pas associée à la survie.<p>Des données récentes ont indiqué que le 3'-UTR de l’ARNm de TYRP1 contient trois sites de<p>liaison putatifs de miR-155 dont deux présentant un polymorphisme d'un seul nucléotide (SNPs:<p>rs683 et rs910) qui favorisent la dégradation en cas d’hybridation miARN-ARNm parfaite de<p>l’ARNm ou non en cas d’hybridation imparfaite. Nous avons cherché à examiner si miR-155 peut<p>affecter l’expression de l’ARNm et de la protéine TYRP1 en fonction de ces SNPs. Tout d'abord,<p>nous avons transfecté deux lignées de mélanome ayant chacune l’une ou l’autre de l’allèle (au<p>niveau rs683 et rs910) avec différentes concentrations de pré-miR-155 et nous avons évalué<p>l’expression du miR-155 et l’ARNm TYRP1 par PCR en temps réel ainsi que l’expression de la<p>protéine TYRP1 par western blot. Nous avons constaté qu’une surexpression de miR-155 a induit<p>une dégradation importante des ARNm TYRP1 et a perturbé sa traduction en protéine dans la lignée<p>avec le génotype “hybridation parfaite”. Ensuite, nous avons examiné l'expression des ARNm et<p>protéines de TYRP1, le niveau de miR-155 et les SNPs rs683 et rs910 dans 192 échantillons de<p>métastases cutanées et ganglionnaires de mélanome. Nous avons trouvé que le groupe d'échantillons<p>avec le génotype “hybridation parfaite” était significativement associé à un niveau de protéine de<p>TYRP1 plus bas alors qu'aucune différence de niveau d’expression n'a été trouvée pour l’ARNm de<p>TYRP1 ou miR-155 entre les deux groupes de génotype, confirmant que les SNPs au niveau de 3’-<p>UTR de TYRP1 peuvent spécifiquement affecter l'expression de la protéine TYRP1. En outre, nous<p>avons montré que l’ARNm de TYRP1 est inversement corrélé avec l’expression miR-155, mais pas<p>avec la protéine TYRP1 dans le groupe " hybridation parfaite", alors qu'il corrèle positivement avec<p>la protéine mais pas avec miR-155 dans le groupe "hybridation imparfaite" où la protéine corrélait<p>inversement à la survie. Cela montre que les SNPs dans le 3'-UTR de l'ARNm TYRP1 affectent la<p>régulation de l’ARNm par miR-155 et la traduction en protéine. Ces SNPs rendent la régulation de<p>l’ARNm et la protéine de TYRP1 indépendante de miR-155 et confèrent une valeur pronostique à<p>la protéine TYRP1 / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished

In the present investigation peripheral blood lymphocytes from patients with inflammatory bowel disease (IBD) and different cancer states were treated with various agents and compared with lymphocytes from healthy control individuals (HCI) treated in the same way and measured in the Comet assay. For inflammatory bowel disease, patient¿s responses in IBD patients treated with H2O2 were higher than in HCI and crohn¿s patients (CD) were found to have higher responses than Ulcerative colitis (UC) patients. The responses for all IBD and HCI were all reduced in the presence of chaga mushroom extract which behaved in an antioxidant manner. A second group of IBD patients were treated with the heterocyclic amine (food mutagen), IQ and H2O2 and responses were reduced in the presence of the flavonoids, quercetin and epicatechin and compared with HCI similarity treated. In all cells responses were reduced with flavonoids and again CD had higher responses than the UC patients and IBD patients higher than HCI. The responses with CD and UC were that confirmed in two independent studies with IBD, one with chaga mushroom extract and the other with flavonoids. Peripheral lymphocytes from malignant melanoma and suspected melanoma patients and colon cancer and polyposis patients were compared to the lymphocytes from HCI and treated with UVA. There were differential sensitivities when measured in the micronucleus and Comet assays. The cancer patients had higher responses than those in the precancerous states and they in turn were higher than responses in HCI. In all the studies, untreated baseline DNA damage values were also higher in IBD and cancer patients and pre-cancerous patients than HCIs. This would suggest that baseline frequencies of different diseases compared to controls could be an important biomarker in the diagnosis of pre-cancers and early stage cancers. Also peripheral lymphocytes are a useful surrogate for cancers and pre-cancerous disease states since, blood is present in all organs and tissues and DNA is basically the same in all cells.

Objetivo: Identificar las características sociodemográficas y epidemiológicas del paciente con cáncer de piel diagnosticados en el servicio de anatomía patológica del Hospital Regional Lambayeque durante periodo enero del 2016 - diciembre del 2019. Métodos: La metodología empleada durante esta investigación estuvo basada en el diseño no experimental, descriptivo, de carácter retrospectivo, trasversal y observacional. Se incluyeron un total de 429 pacientes mayores de 18 años, diagnosticados con carcinoma cutáneo de tipo no melanoma (NPNM) y melanoma, mediante estudios anatomopatológicos de la lesión atendidos en Hospital Regional Lambayeque. La elección de la muestra fue mediante un muestreo no probabilístico de tipo censal, por la adaptabilidad al estudio. Resultados: De un total de 429 pacientes, 256(59,1%) tenían carcinoma basocelular (CBC), 146 (33,7%) carcinoma epidermoide (CsCC) y 31(7,2%) melanoma maligno cutáneo (MM). Siendo la edad promedio de aparición de 71 años en los NPNM y 62 años en el Melanoma Maligno Cutáneo, con predominio por el sexo femenino en el CBC y masculino en CsCC y MM. La ubicación anatómica más comprometida fue de la cabeza en los NPNM y miembros inferiores en MM, los cuales fueron identificadas mayormente por el servicio de Dermatología, seguido por Cirugía de Cabeza y Cuello del hospital. Los años con mayor número de carcinomas cutáneos fueron el 2019 para CBC y 2018 para los dos restantes. Conclusiones: La población general presenta más riesgo de presentar carcinomas no melanómico y en menor número el melanoma maligno, el cual predomina en áreas fotoexpuestas del cuerpo. / Objective: To identify the sociodemographic and epidemiological characteristics of the patient with skin cancer diagnosed in the pathological anatomy service of the Lambayeque Regional Hospital during the period January 2016 - December 2019. Methods: The methodology used during this investigation was based on the non-experimental design, descriptive, retrospective, cross-sectional and observational. A total of 429 patients over 18 years of age were included, diagnosed with non-melanoma skin carcinoma (NPNM) and melanoma, through anatomopathological studies of the lesion treated at Hospital Regional Lambayeque. The selection of the sample was by means of a non-probabilistic sampling of the census type, due to the adaptability to the study. Results: Of a total of 429 patients, 256 (59.1%) had basal cell carcinoma (BCC), 146 (33.7%) squamous cell carcinoma (SCC) and 31 (7.2%) cutaneous malignant melanoma (MM). Being the average age of appearance of 71 years in NPNM and 62 years in Cutaneous Malignant Melanoma, with a predominance of females in CBC and male in CsCC and MM. The most compromised anatomical location was the head in NPNM and lower limbs in MM, which were mostly identified by the Dermatology service, followed by Head and Neck Surgery at the hospital. The years with the highest number of skin carcinomas were 2019 for CBC and 2018 for the remaining two. Conclusions: The general population presents a higher risk of presenting non-melanoma carcinomas and a smaller number of malignant melanoma, which predominates in photo-exposed areas of the body.

Master of Science / Department of Anatomy and Physiology / Deryl L. Troyer / There is renewed interest in magnetic hyperthermia as a treatment modality for cancer, especially when it is combined with other more traditional therapeutic approaches, such as the co-delivery of anticancer drugs or photodynamic therapy. The influence of bimagnetic nanoparticles (MNPs) combined with short external alternating magnetic field (AMF) exposure on the growth of subcutaneous mouse melanomas (B16-F10) was evaluated. Bimagnetic Fe/Fe3O4 core/shell nanoparticles were designed for cancer targeting after intratumoral or intravenous administration. Their inorganic center was protected against rapid biocorrosion by organic dopamine-oligoethylene glycol ligands. TCPP (4-tetracarboxyphenyl porphyrin) units were attached to the dopamine-oligoethylene glycol ligands. The magnetic hyperthermia results obtained after intratumoral injection indicated that micromolar concentrations of iron given within the modified core-shell Fe/Fe3O4 nanoparticles caused a significant anti-tumor effect on murine B16-F10 melanoma with three short 10-minute AMF exposures. There is a decrease in tumor size after intravenous administration of the MNPs followed by three consecutive days of AMF exposure. These results indicate that intratumoral administration of surface-modified MNPs can attenuate mouse melanoma after AMF exposure. Moreover, intravenous administration of these MNPs followed by AMF exposure attenuates melanomas, indicating that adequate amounts of TCPP-labeled stealth Fe/Fe3O4 nanoparticles can accumulate in murine melanoma after systemic delivery to allow effective magnetic hyperthermic therapy in a rodent tumor mode.

Metastatic melanoma is an aggressive, incurable cancer with historically few therapeutic options. The discovery that 60% of melanomas harbor the oncogenic BRAF_V600E mutation, which constitutively activates the MAPK pathway, has provided a promising new therapeutic axis. Although MAPK pathway inhibitor therapy has shown striking clinical results in BRAF_V600-mutant melanoma, this approach faces three limitations. First, 10-20% of BRAF_V600-mutant melanomas never achieve meaningful response to MAPK pathway inhibitor therapy (intrinsic resistance). Second, among BRAF_V600-mutant melanomas initially responding to MAPK pathway inhibitor therapy, relapse is universal (acquired resistance). Third, approximately 40% of melanomas lack BRAF_V600 mutations and so are not currently candidates for MAPK pathway inhibitor therapy. We sought to address each of these problems: by characterizing the phenomenon of intrinsic MAPK pathway inhibitor resistance, by finding ways to perturb mechanisms of acquired MAPK pathway inhibitor resistance, and by identifying novel dependencies in melanoma outside of the MAPK pathway. Intriguingly, the NF-kappa B pathway emerged as a common theme across these investigations. In particular, we establish that MAPK pathway inhibitor sensitive and resistant melanomas display distinct transcriptional signatures. Unlike most BRAF_V600-mutant melanomas, which highly express the melanocytic lineage transcription factor MITF, MAPK pathway inhibitor resistant lines display low MITF expression but high levels of NF-kappa B signaling. These divergent transcriptional states, which arise in melanocytes from aberrant MAPK pathway activation by BRAF_V600E, remain plastic and mutually antagonistic in established melanomas. Together, these results characterize a dichotomy between MITF and NF-kappa B cellular states as a determinant of intrinsic sensitivity versus resistance to MAPK pathway inhibitors in BRAF_V600-mutant melanoma. In separate investigations, we have shown that, NFKB1 p105, a member of the NF-kappa B family, intimately regulates levels of COT, a known effector of resistance to MAPK pathway inhibitors. Moreover, we have used shRNA screening to nominate particular nodes within the NF-kappa B pathway, including MYD88 and IRF3, as candidate melanoma lineage-specific dependencies. Cumulatively, although these studies use diverse approaches to investigate the limitations of MAPK pathway inhibitor therapy in melanoma, they converge in nominating the NF-kappa B pathway as a previously underappreciated feature of melanoma biology and suggest the relevance of this pathway for future investigation.

Despite 35 years of clinical trials, there has been little improvement in one-year survival rates with any chemotherapeutic regimen for the treatment of metastatic melanoma due to resistance to all known agents. Regardless of advances in detection and prevention, diagnosis of metastatic disease remains a death sentence. Resistance mechanisms, including aberrant kinase signaling and drug transport pumps, indicate a need for identification of other therapeutic targets that impinge upon multiple signaling pathways. The Abl family of non-receptor tyrosine kinases (c-Abl, Arg) has been indicted as a causative force in leukemia for more than three decades; however, their role in solid tumors has only recently been described. We first demonstrated that activated Abl family kinases promote breast cancer development and progression, and recently identified them to be novel therapeutic targets in metastatic melanoma cells by demonstrating that they promote proliferation, survival, invasion, and metastasis. We now present evidence that inhibitors of Abl family kinases abrogate resistance to a number of commonly used chemotherapeutics (i.e., 5-fluorouracil, cisplatin, paclitaxel, camptothecin) in a panel of breast cancer cells. We proceed to show that inhibitors of Abl family kinases, likewise, sensitize both breast cancer and melanoma cells to doxorubicin by blocking cell proliferation and dramatically inducing apoptosis. These findings were extended to advanced multi-drug resistant melanoma cells, in which we show for the first time that c- Abl promotes expression of the drug transporter, ABCB1, during acquired resistance, and drugs that inhibit c-Abl/Arg prevent ABCB1 expression and function. Moreover, c-Abl/Arg also promote acquired chemoresistance independent of ABCB1 by modulating multiple survival pathways. We demonstrate that c-Abl/Arg promote chemoresistance by upregulating STAT3, preventing doxorubicin-mediated conversion of NF-κB into a transcriptional repressor, activating an HSP27/p38/Akt survival pathway, and modulating ERK signaling. Therefore, c-Abl/Arg promote chemoresistance in highly resistant melanoma cells by impinging on drug transporter and cell survival pathways. Taken together, these data indicate that c-Abl/Arg inhibitors are likely to reverse acquired resistance in metastatic melanomas harboring activated c-Abl/Arg, and thus, may be effective in a combination regimen.

Comme nous l’indiquions dans le But du Travail, le mélanome figure parmi les cancers associés aux pronostics les plus sombres, et ce en raison de son taux de réponse très faible à la radiothérapie et à la chimiothérapie. Cette résistance à la radiothérapie et à la chimiothérapie provient essentiellement du fait que les cellules de mélanomes sont résistantes à l’apoptose, et que la radiothérapie ainsi que bon nombre d’agents chimiothérapiques induisent la mort des cellules cancéreuses en y induisant l’apoptose. Nous avons voulu investiguer les rôles de la gastrine et de la galectine 1 sur le comportement biologique des cellules de mélanomes afin de voir s’il était possible de proposer la gastrine et/ou la galectine 1 comme nouvelles cibles thérapeutiques potentielles dans le cas du mélanome. Notre stratégie de recherche est basée sur le principe (démontré sur le plan expérimental par de nombreuses études) selon lequel les cellules cancéreuses migrantes résistent à l’apoptose, et sont dès lors protégées contre les effets pro-apoptotiques de la chimiothérapie et de la radiothérapie qui représentent la quasi totalité de l’arsenal thérapeutique dont disposent les oncologues pour combattre les cancers. Diverses études expérimentales ont démontré que le fait de réduire le taux de migration de cellules cancéreuses résistantes à l’apoptose conférait à celles-ci une sensibilité accrue aux agents pro-apoptotiques. Nos résultats démontrent que la gastrine modifie de manière très significative les propriétés migratoires des cellules de mélanomes, sans toutefois modifier leur sensibilité à des agents pro-apoptotiques. Au contraire, la gastrine protègerait les cellules de mélanomes contre l’apoptose. Nous démontrons également dans notre travail, in vivo, un rôle pro-angiogénique pour la gastrine au sein de xénogreffes de mélanomes humains. Signalons que notre travail est le premier à démontrer un rôle potentiel de la gastrine au niveau de la biologie des mélanomes, tout au moins sur le plan expérimental. Tout comme nous l’avons observé pour la gastrine, la galectine 1 semble également conférer aux cellules de mélanomes un certain degré de résistance aux agressions chimiothérapiques. Cette fois, le fait de diminuer le taux d’expression de la galectine 1 au sein de cellules du mélanome murin expérimental B16F10 (qui exprime des quantités importantes de galectine 1) renforce l’effet thérapeutique du témozolomide qui est une molécule cytotoxique. Cet effet semble survenir, tout au moins partiellement, suite à une diminution du taux d’expression de la protéine Hsp70 (suite à la diminution du taux d’expression de la galectine 1), avec pour conséquence une augmentation de la mort cellulaire par perméabilisation de la membrane des lysosomes. Nous proposons une nouvelle approche thérapeutique pour combattre les mélanomes en faisant appel à la technique des petits ARN interférants (siRNA), dirigés dans le cas présent contre la galectine 1.

Nucleotide excision repair (NER) is one of the major repair systems for removal of DNA lesions. The NER pathway has evolved mainly to repair UV-induced DNA damage and is also active against a broad range of endogenously generated oxidative lesions. Defects in NER result in the human inherited disorder xeroderma pigmentosum (XP), which is characterised by UV hypersensitivity and a 1000-fold increased risk of skin cancer. ERCC1 is essential for the NER pathway where it acts in a complex with the XPF protein to make the incision 5' to the DNA lesion. The normal 1.1kb Ercc1 transcript is expressed in all tissues. Our group has discovered a second larger 1.5 kb transcript, which initiates from an alternative promoter, and is the most abundant Ercc1 transcript in mouse skin. The aims of this project were: 1, To investigate the role of ERCC1 and of the 1.5kb skin specific Ercc1 transcript in protecting the skin against UV-induced DNA damage. 2, To study the importance of ERCC1 in melanoma skin cancer and investigate ERCC1as a possible target for therapy against melanoma. Using a panel of Ercc1 wild-type and deficient cells, we established a quantitative western blotting system to study the expression of ERCC1 in a range of mouse tissues and mouse and human cell types. Although the skin-specific Ercc1 transcript was found to be present at much higher levels in the skin of albino compared to pigmented mouse strains, this did not result in an elevated level of ERCC1 protein. We were also unable to demonstrate that UV-irradiation, or other stress-inducing treatments resulted in increased levels of ERCC1 protein in cultured mouse keratinocytes. We investigated the DNA methylation status of the normal Ercc1 promoter and that of two potential upstream promoter regions that were candidates for the source of the 1.5kb skin-specific Ercc1 transcript. We found no evidence that they were the source and, instead, used 5' RACE analysis to locate the skin-specific promoter to a polymorphic region 500bp upstream of the normal initiation site. In albino strains this region contains a SINE element, which we hypothesize could be involved in the production of the skin-specific Ercc1 transcript. We also investigated the protein level of ERCC1 and other DNA repair proteins, including XPF, MSH2, MSH6 and MLH1 in human melanoma cells and ovarian tumour cells. Significantly elevated protein levels of ERCC1 and XPF, as well as the mismatch repair protein MLH1 were found in melanoma cells. This could possibly contribute to the higher resistance to chemotherapy in melanoma, although the melanoma cell lines we tested did not show increased resistance to UV and cisplatin compared to the ovarian cancer cells tested. When Ercc1 proficient mouse melanoma cells were xenografted into nude mice the xenografts grew rapidly. Cisplatin treatment caused an initial shrinkage of the tumours, but re-growth rapidly followed. Cells re-isolated into culture from cisplatin treated xenografts had significantly higher levels of ERCC1 protein than either input cells, or cells re-isolated from untreated xenografts. An isogenic Ercc1 deficient derivative of the Ercc1 proficient mouse melanoma cell line grew as rapidly as the parent line in vitro, but grew much more slowly as xenografts. In addition, the xenografts shrank completely following cisplatin treatment and did not recover. This suggests that ERCC1 could be a drug target for melanoma therapy.

Följande kandidatuppsats undersöker hur en elektronisk hälsoapplikation kan utformasför att öka medvetenheten om den personliga dagliga hälsan, fokuserat på huden och atthålla den frisk. Det sker genom att en prototyp har utformats där användaren genombilder samt text får instruktioner för att utföra en självkontroll. Prototypen innehållerockså en bildregistrering där användaren kan ladda upp bilder på en leverfläck ochgenom registreringen kan om leverfläcken utvecklas över tid. Syftet med prototypen äratt undersöka om en elektronisk hälsoapplikation utformad med fokus på återkopplingkan göra det möjligt för en person som inte är utbildad inom ämnet att undersöka sinhud samt se och följa förändring i en leverfläck genom bildanalys. Detta undersöktesgenom två tester. Ett frågeformulär där svarspersonen fick försöka avgöra om enleverfläck var frisk eller inte. Ett användartest där testpersonen fick testa bildanalysen,det som testades var om personen kunde ladda upp en bild samt se skillnad i bildernagenom bildregistreringen.Resultatet visar att majoriteten av enkätsvaren var korrekta svar, närmare bestämt 76,9procent. Personerna kunde identifiera om leverfläcken var frisk eller sjuk med hjälp avinformationen som tilldelades. Resultatet av användartesten visade att personerna kundeladda upp en bild på webbplatsen och sedan förstå bildanalysen. / This bachelor thesis examins how a electronic health application can be made toincrease awareness about personal daily health, with focus on individual skin andkeeping it healthy. This was made by creating a prototype where the user get usefulinformation on how to perform a self examination through text and images. Theprototype also contains functionality that allows the user to upload images of a moleand by an image registration follow possible changes over long periods of time. Thepurpose of the prototype is to investigate if an electronic health application with focuson feedback can make it possible for a person who is not educated in this area to examinthe skin and also discover possible changes over time with the image registration. Twotests were made to examin if this was possible. The first test was an questionnaire wherethe respondet tried to determine if a mole was healthy or not. The second test was a usertest where the test person got to try out the functionality with image registration in theprototype. The person got to upload an image and see the differences through the imageregistration.The results showed that the majority of the collected repsonses from the quetsionnairewas correct, with a percentage of 76,9 correct answers. The respondent could identify ifthe mole was healthy or not through the information that was presented. The results ofthe user test showed that all test persons could perform and understand the functionalityof uploading an image and then analyze the results throgh image registration.

Précédemment, il a été démontré au laboratoire qu’une vaccination des souris avec des lipopolyplexes (LPR) contenant l’ARNm de l’antigène de mélanome MART1 permet d’induire la formation de lymphocytes T cytotoxiques spécifiques et de retarder le développement de mélanomes B16F10 et de métastases pulmonaires. Les LPR sont des complexes ternaires constitués d’ARNm, d’un polymère cationique histidylé et de liposomes cationiques histidylés. L’objectif de ma thèse était d’améliorer cette vaccination antitumorale en développant de nouveaux liposomes capables de cibler les cellules dendritiques (DC). Le ciblage a été réalisé en incorporant un glycolipide mannosylé aux liposomes afin de favoriser leur reconnaissance par le récepteur mannose. A partir de ces liposomes, des formulations de complexes ternaires à base d’ADN (LPD mannosylés ou Man11-LPD100) ou à base d’ARN (LPR mannosylés ou Man11- LPR100) ont été mis au point. Les résultats montrent que : in vitro les formulations Man11-LPD100 sont mieux internalisés et transfectent plus efficacement les DC que les LPD100 non mannosylés. Les formulations Man11-LPR100 transfectent avec une plus grande efficacité les DC par rapport aux Man11- LPD100. Par ailleurs, une forte réduction de la toxicité des formulations a été obtenue en dialysant les liposomes. Il est également possible de conserver les formulations sous forme déshydratée. Une imagerie par scintigraphie effectuée chez la souris a permis de constater que 9% des LPD sont captés dans la rate après une injection IV. Nous avons mis en évidence après un isolement de DC spléniques que les formulations Man11-LPR100 transfectent 4 fois plus de DC que les LPR non manosylés. Enfin, l’immunisation des souris avec Man11-LPR100 contenant l’ARNm MART1 permet une vaccination plus efficace contre la tumeur B16F10 et une meilleure survie. En conclusion, les LPR Man11-LPD100 sont de bons vecteurs pour cibler et transfecter les DC spléniques avec l’ARNm d’un antigène tumoral et pour induire la réponse immune contre les cellules tumorales. / Previously, it has been demonstrated that mice vaccination with lipopolyplexes (LPR) containing melanoma antigen MART1 mRNA can induce the generation of specific cytotoxic T cells and delay B16F10 melanoma growth and lung metastases. LPR are ternary complexes consisting of mRNA, a histidylated cationic polymer and histidylated cationic liposomes. The objective of my thesis was to enhance this antitumor vaccination through the development of new liposomes that can target specifically dendritic cells (DC). The targeting of DC was achieved by incorporating a mannosylated glycolipid within liposomes to enhance their recognition by the mannose receptor. From these liposomes, formulations based ternary complexes of DNA (mannosylated-LPD or Man11-LPD100) or formulations based on mRNA (mannosylated LPR or Man11 LPR100) were developed. The results show that formulations made with Man11-LPD100 are better internalized and transfect efficiently DC than LPD100. Man11 LPR100 transfect with greater efficiency DC compared to DNA based formulation (Man11-LPD100). Furthermore, a strong reduction of the toxicity of LPD was obtained by liposomes dialysis. It is also possible to preserve their activity by freeze-drying. Mice scintigraphy revealed that 9% of LPD are captured in the spleen following IV injection. We demonstrated after isolation of splenic DC that Man11-LPR100 transfect DC 4 times more than LPR100. Finally, immunization of mice with Man11-LPR100 containing mRNA MART1 allows a more effective vaccination against B16F10 tumor and a better mice survival than non-mannosylated ones. In conclusion, Man11-LPR100 are promising vectors to target and transfect splenic DC with a tumor antigen mRNA aiming to an induction of an immune response against tumor cells.