Alterações mitocondriais e tumorigênese de câncer gástrico em Sapajus apella

Abstract

Cancer is the name given to a variety of diseases that can occur in different regions of the body, which is characterized primarily by the deregulated proliferation of cells. A very important organelle in both normal and mutated cells is mitochondria, responsible for most of the ATP production in the cell. Mutations in mitochondrial DNA can lead to apoptosis or influence the efficiency of ATP formation. Considering several different estimates, gastric cancer still in the five most incidental in world population, as well as in Brazilian and local population. In this way, understanding tumor behavior becomes important for fight against this pathology. With this, the objective of the present work was to analyze presence of mitochondrial DNA alterations of gastric carcinoma lines implanted in an animal model. Four mitochondrial genes (COI, ATPase 8, ND1 and ND3) from four gastric cancer strains (AGP01, ACP02, ACP03 and PG100) and one control (Carcinossarcoma 256 from Walker) were analyzed to evaluate possible mitochondrial DNA mutations. These strains were inoculated in non-human primates of the Sapajus apella species, and some animals received the carcinogenic substance N-methyl-N-nitrosurea (MNU) concomitantly with the strains. The gastric tumors that developed in the animals were surgically removed, after which DNA extraction, amplification and sequencing of the sequences of interest were done. Changes were observed in the ND1 and ND3 genes. The two transitions found in ND1, one at position 3594 (CT) and 3693 (GA) of mitochondrial DNA, had no associated pathological record and were related to population markers. The AG transition at position 10398 of the ND3 gene resulted in the change from one threonine to alanine in the resulting amino acid, only in lines with more aggressive behavior or after MNU administration. Two heteroplasms were also identified in the ND1 gene at positions 3594 (C / T) and 3693 (A / G) only in the PG100 line after MNU, suggesting a difference in the DNA repair system of this line compared to the others. The results suggest that changes in the genes encoding proteins that participate in Complex I of the respiratory chain are more frequent than in other portions of the mtDNA in the analyzed gastric carcinoma strains.