Análise molecular da “matrix metalloproteinase 13” em ameloblastomas

Abstract

Ameloblastoma is a benign odontogenic tumor of epithelial origin. It might have aggressive, infiltrative and destructive behavior. The recommended treatment is surgical resection with a safety margin to reduce the chance of recurrence. This therapeutic approach results in facial deformation and aesthetic impairment. The presence of BRAF p.V600E mutation in ameloblastomas has been extensively reported and this genetic alteration leads to constitutive activation of the MAPK/ERK pathway, culminating in dysregulation of cellular processes, such as cell proliferation. Despite the high frequency of alterations in the MAPK/ERK pathway in ameloblastomas, the impact of this finding on the biology of these lesions is unknown. It is believed that the constitutive activation of the MAPK pathway can lead to increased expression of proteins that degrades the extracellular matrix, such as MMP13, an enzyme associated with the invasion of neoplastic cells. In the present study, we investigated the expression of MMP-13 in ameloblastoma samples using RT-qPCR. The enzymatic activity of MMP-13 was analyzed using Zymography assay. Western Blotting assays were conducted to analyze the activity of the MAPK pathway, through the detection of the phosphorylated effector pERK, and for a possible correlation between pERK activity and MMP13 protein expression. Our study shows high levels of mRNA MMP-13 in ameloblastoma (12/12) compared to paired normal mucosa. The collagenolytic activity of this MMP was observed in all samples analyzed (7/7). Activation of the MAPK pathway was detected in ameloblastomas samples (7/7), regardless of BRAF p.V600E mutation status. An association between MAPK/ERK pathway activation and MMP-13 protein expression in ameloblastomas was not observed. Further studies are needed to clarify the impact of the MAPK pathway on the regulation of MMP-13 expression and the role of MMPs in the invasive behavior of ameloblastomas.