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Submitted by Isabela Fernanda Spinelli Perossi (isabela.perossi@unesp.br) on 2022-04-03T15:48:15Z No. of bitstreams: 1 Dissertação Isabela Fernanda Spinelli Perossi.pdf: 1723514 bytes, checksum: 7872279c3a389cf1d66c1ecd044ca121 (MD5) Approved for entry into archive by Vivian Letícia Duarte Parisi (vivian.parisi@unesp.br) on 2022-04-04T14:06:49Z (GMT) No. of bitstreams: 1 perossi_ifs_me_sjrp.pdf: 1723514 bytes, checksum: 7872279c3a389cf1d66c1ecd044ca121 (MD5) Made available in DSpace on 2022-04-04T14:06:49Z (GMT). No. of bitstreams: 1 perossi_ifs_me_sjrp.pdf: 1723514 bytes, checksum: 7872279c3a389cf1d66c1ecd044ca121 (MD5) Previous issue date: 2022-03-07 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) O câncer de mama (CM) é um relevante problema de saúde pública, pois representa a segunda principal causa de morte relacionada ao câncer em mulheres em todo o mundo. Os cães são utilizados como modelo para estudos desses tumores, pois além da grande ocorrência, possuem semelhanças biológicas e fisiopatológicas. A via PIK3CA/AKT/mTOR está fortemente desregulada no câncer de mama e desempenha papel central na homeostase celular. A literatura recente retrata que todas as mutações somáticas identificadas a partir do gene PIK3CA alteraram as sequências de aminoácidos, dentre eles a variante c.3140A> G. Esse gene participa da regulação de uma ampla gama de atividades celulares relevantes englobando várias proteínas importantes. Na medicina veterinária o estudo desta via é incipiente. O objetivo deste trabalho foi analisar a variante c.3140A>G do gene PI3KCA e a expressão das proteínas alvo PIK3CA, PTEN, HIF, VHL, ZEB1, ZEB 2, Caspase-3 e PARP1 como marcadores prognósticos em um estudo prospectivo, verificando a expressão gênica dessa variante e, em um estudo retrospectivo, avaliando a expressão proteica e gênica de alvos moleculares à jusante da via correlacionando com o prognóstico nas cadelas. No estudo retrospectivo, o DNA de 24 fragmentos de tumores mamários caninos e 20 fragmentos normais de mama de cadelas foi extraído e a mutação verificada usando TaqMan® Mutation Detection Assay. A imunohistoquímica foi realizada com o kit Reveal HRP Conjugate e sua análise pelo método Histoscore. Duas pacientes (8,3%) apresentaram a mutação c.3140A> G, sendo que uma paciente apresentou metástase pulmonar e morreu em 30 dias após o diagnóstico e a outra paciente permanece viva. Os dados de imunohistoquímica revelaram que a expressão das proteínas PIK3CA, HIF, ZEB2 e PARP1 foi maior na paciente que veio a óbito em comparação com a que permanece viva (p G. This gene participates in the regulation of a wide range of relevant cellular activities encompassing several important proteins. In veterinary medicine, the study of this pathway is incipient. The objective of this work was to analyze the c.3140A>G variant of the PI3KCA gene and the expression of the target proteins PIK3CA, PTEN, HIF, VHL, ZEB1, ZEB 2, Caspase-3 and PARP1 as prognostic markers in a prospective study, verifying the gene expression of this variant and, in a retrospective study, evaluating the protein and gene expression of molecular targets downstream of the pathway correlating with the prognosis in bitches. In the retrospective study, DNA from 24 canine mammary tumor fragments and 20 canine normal mammary fragments was extracted and mutation verified using the TaqMan® Mutation Detection Assay. Immunohistochemistry was performed with the Reveal HRP Conjugate kit (Spring®) and its analysis was performed using the Histoscore method. Two patients (8.3%) had the c.3140A>G mutation, one patient had lung metastasis and died within 30 days of diagnosis and the other patient remains. Immunohistochemistry data revealed that the expression of PIK3CA, HIF, ZEB2 and PARP1 proteins was higher in the patient who died compared to the one who remained alive (p

We investigated the effects of AET on myomiRs expression in the skeletal muscle and serum of colon cachectic (CT26) and breast non-cachectic (MMTV-PyMT) cancer mice models. Colon cancer decreased microRNA-486 expression, increasing PTEN in tibialis anterior muscle (TA), decreasing the PI3K/mTOR protein pathway, body and muscle wasting, fibers’ cross-sectional area and muscle dysfunction, that were not preserved by AET. In contrast, breast cancer decreased those muscle functions, but were preserved by AET. In circulation, the downregulation of microRNA-486 and -206 in colon cancer, and the downregulation of microRNA-486 and upregulation of microRNA-206 expression in breast cancer might be good cancer serum biomarkers. Since the microRNA-206 is skeletal muscle specific, their expression was increased in the TA, serum and tumor in MMTV, suggesting a communication among these three compartments. The AET prevents these effects on microRNA-206, but not on microRNA-486 in MMTV. In conclusion, cancer induced a downregulation of microRNA-486 expression in TA and serum of CT26 and MMTV mice and these effects were not prevented by AET, however, to MMTV, the trained muscle function was preserved, probably sustained by the downregulation of microRNA-206 expression. Serum microRNA-206 is a potential biomarker for colon (decreased) and breast (increased) cancer to monitor the disease evolution and the effects promoted by the AET.

INTRODUCTION: The activation of the phosphoinositide 3-kinase (PI3K)/AKT signalling pathway is one the most frequent genetic events in breast cancer, consequently the development of PI3K inhibitors has attracted much attention. Here we evaluate the effect of PI3K inhibition on global gene expression in breast cancer cells. METHODS: We used a range of methodologies that include in silico compound analysis, in vitro kinase assays, cell invasion assays, proliferation assays, genome-wide transcription studies (Agilent Technologies full genome arrays), gene set enrichment analysis, quantitative real-time PCR, immunoblotting in addition to chromatin immunoprecipitation. RESULTS: We defined the physico-chemical and the biological properties of ETP-45658, a novel potent PI3K inhibitor. We demonstrated that ETP-45658 potently inhibited cell proliferation within a broad range of human cancer cells, most potently suppressing the growth of breast cancer cells via inhibiting cell cycle. We show that this response is Forkhead box O (FOXO) protein dependent and p53 independent. Our genome-wide microarray analysis revealed that the cell cycle was the most affected biological process after exposure to ETP-45658 (or our control PI3K inhibitor PI-103), that despite the multiple transcription factors that are regulated by the PI3K/AKT signalling cascade, only the binding sites for FOXO transcription factors were significantly enriched and only a subset of all FOXO-dependent genes were induced. This disparity in gene transcription was not due to differential FOXO promoter recruitment. CONCLUSIONS: The constitutive activation of PI3Ks and thus the exclusion of FOXO transcription factors from the nucleus is a key feature of breast cancer. Our results presented here highlight that PI3K inhibition activates specific FOXO-dependent genes that mediate cell cycle arrest in breast cancer cells. R Hill is the recipient of a Fundação para a Ciência e a Tecnologia (FCT) 2012 research grant n° SFRH/BPD/84634/2012. R Kalathur is the recipient of a Fundação para a Ciência e a Tecnologia (FCT) research grant n° SFRH/BPD/70718/2010. We thank B. Vogelstein (Johns Hopkins University, Baltimore, USA) for our [p53−/−] HCT116 cell line. Sí

Recentemente suspeitas de que mecanismos epigenéticos poderiam estar relacionados à fisiopatologia da depressão foram levantadas. Estudos recentes indicam que as alterações na transcrição gênica, induzidas por estresse ou por drogas antidepressivas, parecem envolver mecanismos epigenéticos. Nesse sentido, resultados preliminares de nosso grupo de pesquisa indicaram pioneiramente inibição global da metilação de DNA através da administração sistêmica do agente inibidor da DNA metiltransferase (DNMTs), 5-aza-2-deoxicitidina (5-azaD), induz efeito tipo-antidepressivo, dose-dependente, no modelo animal do nado forçado em ratos(Sales et al., 2011). O córtex pré-frontal medial ventral (CPFMv) é uma estrutura límbica intimamente relacionada com a neurobiologia da depressão. Evidências recentes indicam que o efeito tipo-antidepressivo aparece associado a aumento dos níveis da neurotrofina BDNF (brain derived neurotrophic factor) e de seu receptor TrkB no CPFMv, sendo a sinalização intracelular mediada pela ativação da proteína m-TOR. Contudo, não há evidências de que esses mecanismos moleculares estariam envolvidos nos efeitos induzidos pelos inibidores da metilação do DNA. Sabe-se, no entanto, que tanto o BDNF quanto TrkB têm sua expressão regulada por metilação do DNA. Diante disso, o objetivo presente trabalho será investigar a participação da via BDNF-TrkB-mTOR do CPFMv no efeito antidepressivo induzido por inibidores da metilação de DNA. Para tanto, ratos tratados com inibidores da metilação de DNA (5-azaD ou RG-108), em dois momentos diferentes (imediatamente após o PT e 23horas após o PT) foram submetidos ao teste do nado forçado (FST). Outro grupo de animais recebeu uma injeção intra-CPMv de k252a ou Rapamicina, 40 minutos antes do teste e uma injeção de BDNF intra-CPFMv, 30 minutos antes do teste. Em outro experimento, grupos independentes de animais submetidos ao nado forçado foram tratados sistemicamente com RG-108 e receberam injeção intra-CPFMv de K252a (antagonista de Trk) ou de rapamicina (inibidor da m-Tor), a fim de investigar se o efeito dessas drogas depende da via BDNF-TrkB-mTOR no CPFMv. Um grupo independente foi tratado com RG108 e CPFM desses animais foi dissecado para posterior análise da expressão de BDNF, TrkB e m-TOR, bem como da metilação de DNA. O tratamento com RG108 e 5azaD sistêmico reduziu o tempo de imobilidade dos animais submetidos ao nado forçado nos dois tempo de administração. A administração intra-CPFMv de BDNF promoveu efeito antidepressivo no FST, e esse efeito foi bloqueado pela administração de k252a ou Rapamicina no CPFMv. No mesmo sentido, o efeito antidepressivo do RG108 sistêmico foi bloqueado pela administração intra-CPFMv de k252a ou Rapamicina. Entretanto, a medida dos níveis de metilação global no CPFMv não apresentou alteração como tratamento com RG108, e também não mostrou alteração nos níveis de BDNF presente no CPF. O tratamento com RG108 não alterou a expressão, bem como a ativação de TRkB e mTOR. Concluímos que os inibidores da metilação do DNA apresentam agudamente efeito tipo antidepressivo rápido, que necessita da funcionalidade integral da via BDNF-TRkB-mTOR. Entretanto, esse efeito parece não alterar a síntese e expressão das proteínas envolvidas nessa via no que diz respeito ao CPFmv. Recent studies indicate that changes in gene transcription induced by stress or antidepressant drugs appear to involve epigenetic mechanisms. Accordingly, results of our research group pioneered indicated global inhibition of DNA methylation through systemic administration of an inhibitor of DNA methyltransferase (DNMTs), 5-aza-2-deoxycytidine (5-AzaD), induces antidepressant-like effect dose-dependent in the animal model of forced swimming in rats (Sales et al., 2011). The ventral medial prefrontal (vmPFC) cortex is a limbic structure closely related to the neurobiology of depression. Recent evidence indicates that the antidepressant-like effect appears associated with increased levels BDNF (Brain derived neurotrophic factor) and its receptor TrkB in vmPFC, and intracellular signaling mediated by activation of protein mTOR. However, there is no evidence that these molecular mechanisms are involved in the effects induced by inhibitors of DNA methylation. It is known, however, both as BDNF and TrkB expression is regulated by DNA methylation. Thus, the goal of this work is to investigate the role of BDNF-TRkB pathway mTOR-vmPFC in the antidepressant effect induced by inhibitors of DNA methylation. To this end, rats treated with inhibitors of DNA methylation (5-Azad or RG-108), at two different times (immediately after 23hours after the PT and PT) were subjected to the forced swim test (FST). Another group received an intra-vmPFC injection of K252a or Rapamycin 40 minutes before the test, and an injection intra-vmPFC of BDNF 30 minutes before the test. In another experiment, separate groups undergoing the forced swim were treated systemically with RG-108 and received intra-vmPFC of K252a (Trk antagonist) or injection of rapamycin (m-Tor inhibitors) in order to investigate the effect these drugs depends on BDNF-TrkB-mTOR pathway in vmPFC. A separate group was treated with RG108 and mPFC these animals were dissected for analysis of the expression of BDNF and TrkB m-TOR, as well as DNA methylation. The systemic treatment whit 5azaD and RG108 reduced the immobility time of rats subjected to FST administration in both time. The intra-vmPFC BDNF administration promoted antidepressant effect in the FST, and this effect was blocked by the administration of K252a or Rapamycin in vmPFC. Similarly, the antidepressant effect of systemic RG108 was blocked by intra-vmPFC of K252a or Rapamycin administration. However, the measurement of the levels of global methylation in CPFMv did not change as treatment with RG108, and also showed no change in the levels of BDNF present in the CPF. Treatment with RG108 did not alter the expression and activation of TrkB and mTOR. We conclude that inhibitors of DNA methylation present acutely antidepressant-like effect, it needs the full functionality of the BDNF-TrkB-mTOR pathway. However, this effect seems not to alter the synthesis and expression of proteins involved in this pathway at vmPFC.