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Proteomic alterations in different models of epithelial-mesenchymal transition (EMT) induction in breast adenocarcinoma cells

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Author(s):
Camila de Souza Palma
Total Authors: 1
Document type: Doctoral Thesis
Press: Ribeirão Preto.
Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
Defense date:
Examining board members:
Vitor Marcel Faça; Claudio Miguel da Costa Neto; Leo Kei Iwai; Francisco José Cândido dos Reis; Daniel Martins de Souza
Advisor: Vitor Marcel Faça
Abstract

Tumor development is a process comprising several steps and consists in the progressive development of normal cells into a neoplastic state through various biochemical and phenotypic changes. Among the major marks of cancer are the capacity for tissue invasion and metastasis. Metastasis accounts for approximately 90% of cancer deaths. Thus, the most effective methods for improving cancer-related morbidity and mortality rates are early detection, prevention and treatment of metastasis. The EMT process, which occurs naturally during embryogenesis and tissue repair, is also involved in cancer progression and metastasis. EMT induces complex cellular and microenvironmental changes that result in the acquisition of a mesenchymal phenotype by epithelial cells, together with an increase in migratory and invasive cellular capacities. EMT can be induced by various extracellular factors, such as TGF?, EGF, HGF and PDGF. In addition, overexpression of some transcription factors such as SNAIL, SLUG, ZEB1 and TWIST1 is also capable of inducing EMT in vitro. In order to increase the knowledge of the mechanisms involved in the EMT process, we performed proteomic analysis in different models of EMT induction in the MCF7 breast adenocarcinoma cell line, which were the overexpression of SNAIL, treatment with the histone deacetylase inhibitor SAHA and treatment with the growth factor EGF. The detailed proteomic analysis by LC-MS/MS of the subcellular fractions of nucleus, cytoplasm and membrane of the overexpressing SNAIL cells generated a list of regulated proteins related to the EMT process and that were evaluated in the other models of induction. Among these, the HDAC1 protein, which had its levels decreased by SNAIL overexpression. Treatment of the MCF7 cell line with the histone deacetylase inhibitor SAHA showed a positive correlation with the increase of SNAIL levels, suggesting a cross-talk between both proteins. In addition, SAHA treatment induced cellular and protein alterations that also suggest the induction of the EMT process in MCF7 cells. Finally, the treatment with the growth factor EGF was also able to induce the EMT in MCF7 cells and showed involvement in the regulation of the cell cycle, changes in proteins in common with the other treatments and differential regulation of proteins among thesubcompartiments, indicating similarities between the processes and potential mechanisms of subcellular translocation. In conclusion, this study revealed target proteins related to EMT, opening possibilities to try to alter processes related to tumor progression and metastatic process. (AU)

FAPESP's process: 15/08693-0 - Targeted proteomics of subcellular translocation during breast cancer development
Grantee:Camila de Souza Palma
Support Opportunities: Scholarships in Brazil - Doctorate