Expression of gap junction proteins, the connexins, in normal and neoplastic osseous tissues from dogs

Author(s)

Daniel Soares Sanches

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2008-09-30

Examining board members

Maria Lucia Zaidan Dagli; José Luís Avanzo; José Luiz Guerra

• Advisor: Maria Lucia Zaidan Dagli

Abstract

Increasing evidence indicates that junctional communiction by gap juctions has a critical role in a bone physiology. The main connexin (Cx) express involved in development, differentiation and regulation of tissue growth, is the called Cx43. However, other, two connexis are expressed: Cx45 and Cx46. Cx46 is retained as monomers in a trans-golgi compartment of osteoblastic cells. Alterations in the expression profile and aberrant localization of the conexinas have been associated to oncogenesis, demonstrating a reduction of the expression of these conexins in neoplastic tissues. In the present study, we aimed at evaluating the expression of Cx43 and Cx46 in normal and neoplastic osseous tissues from dogs, by means of immunofluorescence, Western blot and Real time- PCR. These results were correlated with the routine histological evaluation of the bone tumor. Results showed that the levels of genetic expression of Cx43 were similar in both normal and neoplastic osseous tissues from dogs, and the Cx43 were found both in the cytoplasm and in the cytoplasmic membrane. Connexin 46 was found in the perinuclear region of neoplastic osteoblasts, and different levels of genic expression were found between normal and neoplastic osseous tissues. We can conclude that the Cx43 is similarly expressed by both normal and neoplastic osteoblasts from dogs, however there are differences in the expression of Cx46. These results point to a possible role of connexins 43 and 46 in dog bone tumors. (AU)