Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2019-03-15T11:31:48Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Louise Nicolle Bach.pdf: 1549158 bytes, checksum: f6d6348279d210b0576bb37a8562f3a4 (MD5) / Made available in DSpace on 2019-03-15T11:31:48Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Louise Nicolle Bach.pdf: 1549158 bytes, checksum: f6d6348279d210b0576bb37a8562f3a4 (MD5) Previous issue date: 2016-12-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / ntrodução: O Melanoma é a principal neoplasia em cavidade oral de cães domésticos. Ocorre principalmente em gengiva, e caracteriza-se pela progressão acelerada, altos índices de recidiva, metástase e resistência a terapias propostas. Tais aspectos impulsionaram o presente estudo, considerando a ausência de um modelo experimental para essa neoplasia, que possibilite a realização de ensaios pré-clínicos. Objetivos: Induzir a formação de melanoma oral murino em camundongos C57Bl/6J, e estudar suas características macroscópicas e histopatológicas. Método: trata-se de um estudo experimental. Trinta camundongos C57Bl/6J (Mus musculus) foram submetidos a indução tumoral através da injeção de células da linhagem de melanoma murino B16F10 em gengiva inferior direita porção vestibular, em duas concentrações celulares, originando dois grupos distintos: Grupo 1 (n=15) que receberam 0,1 ml contendo 1x104 células de melanoma murino B16F10; Grupo 2 (n=15) que receberam 0,1 ml contendo 5x104 células de melanoma murino B16F10. Para ambos os grupos foram realizadas eutanásias programadas aos sétimo, décimo quarto e vigésimoprimeiro dias de pós-operatório, com ressecção ex-vivo da hemicabeça direita. Após a exclusão dos indivíduos que foram a óbito antes do período determinado para eutanásia, obteve-se um número de indivíduos na amostra (n) de 21. Foi realizada análise macroscópica das formações tumorais. Para o estudo histológico comparativo, analisaram-se amostras de melanoma oral canino melânico no que tange aos aspectos morfométricos e morfológicos. Resultados: Houve diferença no desenvolvimento tumoral para cada concentração celular utilizada na indução. Notouse correlação positiva entre volume tumoral e número de células. Conclusão: A indução de melanoma oral em camundongos para fins de modelo de estudo pré-clínico para cães se mostrou uma alternativa útil, viável e reproduzível. / Introduction: Melanoma is the most common neoplasm in oral cavity of dogs. Melanoma has a predilection for the gum, and it is characterized by accelerated progression and high rates of relapse, metastasis and resistance to proposed therapies. Those factors inspires the present study, considering the lack of an experimental model for melanoma. Method: This is an experimental study. Thirty C57Bl / 6J mice (Mus musculus) were submitted to tumor induction by injecting murine melanoma B16F10 cells into the right lower gum using two different cell concentrations. Mice were divided in two groups: Group 1 (n = 15) received 1x104 murine melanoma B16F10 cells injection; Group 2 (n = 15) received 5x104 murine melanoma B16F10 cells injections. For both groups, euthanasia was scheduled at the 7th., 14th. and 21th. postoperative day, with post-mortem hemi-resection of the jaw. Individuals who died before the euthanasia period were excluded, leaving 21 mice. Macroscopic analysis of tumor formations was performed. For comparative histological study, oral canine melanoma samples were analyzed for morphological aspects. Data sete analyzed with BioStat 5.3 and submitted to non-parametric statistical tests. Results: Different tumor characteristics (tumor volume, presence of irregular margins, ulceration and dark coloration) were observed for each cell concentration used in the induction, as well perfect correlation between tumor volume and tumor growth. Conclusion: The induction of oral melanoma in mice for purposes of preclinical study model for dogs is an useful, viable and reproducible alternative.

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.