Banca de QUALIFICAÇÃO: CAIO CÉSAR DA SILVA BARROS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : CAIO CÉSAR DA SILVA BARROS
DATE: 28/06/2022
TIME: 15:00
LOCAL: PLATAFORMA REMOTA
TITLE:

STUDY OF CELLULAR CANNIBALISM AND EPIGENETIC MODIFICATION OF HISTONES IN GIANT CELL LESIONS

KEY WORDS:

Giant cell; Giant cell tumor; Giant cell granuloma; Histones; Inhibitor of growth protein 5

PAGES: 47
BIG AREA: Ciências da Saúde
AREA: Odontologia
SUMMARY:

Multinucleated giant cells (MGCs) are formed from the fusion of monocytic/macrophage lineage cells. These cells can be found in normal tissues and pathological conditions, such as peripheral giant cell granuloma (PGCG), central giant cell granuloma (CGCG), and giant cell tumor (GCT). Although these lesions show similarity in their microscopic findings, they present different biological behavior. PGCG exhibits indolent clinical behavior and GCT is characterized as a benign neoplasm with aggressive behavior. On the other hand, the CGCG presents a varied behavior and can be clinically classified as non-aggressive or aggressive. Thus, several cellular mechanisms have been studied to clarify the different clinical behaviors of CGCG of the jaws. Recently, the role of cellular cannibalism in benign neoplastic lesions with aggressive clinical behavior, malignant neoplasms, and metastatic lesions has been investigated. Cell cannibalism is a process in which a smaller cell is engulfed within the cytoplasm of a larger cell. This process has been frequently identified in malignant neoplasms and giant cell lesions. Cellular processes, such as cellular cannibalism, are initiated from the regulation of gene expression, which may occur through changes in the organization of the chromatin structure caused by epigenetic alterations such as histones acetylation and deacetylation. In this context, the inhibitor of growth protein 5 (ING5) gains importance in the activation of these cellular processes due to its participation in the formation of complexes of histone acetyltransferase enzymes, which carry out the acetylation of histones; where the acetylation of histones H3 and H4 have been associated with cellular processes involved in the carcinogenesis of several neoplasms. Thus, this research aims to morphologically evaluate cellular cannibalism and the immunohistochemical expression of the ING5 protein and the acetylation of histone H3 lysine 9 (H3K9) and histone H4 lysine 8 (H4K8) and its association with clinical behavior in cases of PGCG, non-aggressive and aggressive CGCG and in GCT and, also, to identify whether these epigenetic alterations constitute events associated with the pathogenesis of the analyzed lesions. The sample will consist of 20 cases of PGCG, 20 cases of non-aggressive CGCG, 20 cases of aggressive CGCG, and 19 cases of GCT. For the morphological analysis, all specimens will be evaluated by two examiners according to the “zig-zag” methodology described by Sarode et al. (2014). The immunoexpression analysis of ING5 and the H3K9 and H4K8 acetylation will be performed quantitatively and based on their intracellular location, cytoplasm and/or nucleus, in the mononuclear cells and the MGCs that constitute the lesions. The analysis of clinical, morphological, and immunohistochemical parameters will be performed using Student's t and Mann-Whitney tests. For all evaluations, significant values with p < 0.05 will be considered.

COMMITTEE MEMBERS:
Presidente - 2492713 - ERICKA JANINE DANTAS DA SILVEIRA
Interna - 1258693 - LELIA MARIA GUEDES QUEIROZ
Interna - 1298808 - MARCIA CRISTINA DA COSTA MIGUEL