Evaluation of the expression of the tumor suppressor gene PTEN, of the proto-oncogene c-kit, matrilisin (MMP-7), connexins 32, 43 and of the e-cadherin/catenin complex in canine mast cell tumors

• Grant number: 11/13260-5
• Support type: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): November 01, 2011
• Effective date (End): February 28, 2014
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal researcher: Maria Lucia Zaidan Dagli
• Grantee: Ivone Izabel Mackowiak da Fonseca
• Home Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Mast cell tumors are malignant skin formations originating from mast cells and appear frequently in dogs. Clinical and histological cutaneous canine mast cell tumors provide useful prognostic information, but the clinical course of this neoplasm is unpredictable need for additional factors to predict its evolution. The management of mast cell consists of a challenging task given that adjuvant therapies are notoriously toxic, associated with significant morbidity. Allied to this, the clinic-pathological prognostic factors do not adequately predict current disease recurrence and survival in a significant number of animals. Current molecular and clinical research related to cancer progression are focused on delineating the precise types of molecular alterations that occur at each stage of the progression of this disease and to define the biochemical and biological impact of these changes in the mechanisms that govern proliferation, differentiation and the relationship intercellular these cells. Many markers have been studied in an attempt to establish a correlation of its expression with current prognostic factors, the risk of progression, metastasis and survival of animals with cancer. Among them, we have c-kit (receptor tyrosine kinase) responsible for the maturation and differentiation of mast cells. Other molecules considered tumor suppressor and tumor proliferation markers are being studied in human cancers, as well as in animals, among them that the PTEN tumor suppressor gene and the protein complex of cell adhesion to E-cadherin, ²-catenin, ±- catenin and p120-catenin, and a few molecules of cell communication, called connexins (Cx43 and Cx32), as well as matrix metalloproteinases, among them we have the metalloproteinase matrilysin (MMP-7). The aim of these researchers is to identify genes that may be associated with the development and progression of tumors in humans and animals. Veterinary Medicine lacks studies directed at understanding the molecular signaling pathways in specific diseases such as canine cancer. Among them we have canine mast cell tumors, this neoplasm whose clinical course is unpredictable and there is always need for additional factors to predict its evolution. To understand the relationship of mast cells and intercellular mechanisms that trigger the neoplastic transformation of these cells, we propose a study on this project in three grades of paraffin-embedded canine mastocytoma in order to characterize the expression profile and distribution of proteins in situ c-kit, PTEN, MMP-7, E-cadherin, ²-catenin, ±-catenin, p120-catenin by immunohistochemistry and connexins (Cx43 and Cx32) by immunofluorescence. We also propose to establish three degrees of the culture of canine mastocytoma and mast cells of normal canine skin, for a study of ex vivo, and assess the expression of these proteins and their messenger RNAs in tumor mast cells and compare them with normal, using techniques for this Western blot and RT-PCR. In these cells established in culture, also perform immuno-cytochemical analysis to characterize the expression profile and distribution of these proteins. (AU)