Study of the mechanism of action of the protease inhibitor EcTI and structurally related synthetic peptides on human leukemic cell lines.

Abstract

Several studies describe the action of protease inhibitors on blood coagulation, digestive and inflammatory processes, tissue remodeling, the same molecules are also able to regulate proliferation, apoptosis and cell cycle. EcTI, a 20 kDa inhibitor isolated from Enterolobium contortisiliquum seeds, inhibits trypsin, chymotrypsin, human plasma kallikrein (HuPK), plasmin and human neutrophil elastase, and is involved in the MMP-2 and MMP-9 activation. It was already demonstrated the effect of EcTI on colorectal and breast cancer cell lines viability, as well as on human leukemia cells (K562 and THP-1), proposed in this study. EcTI also inhibits the invasion of gastric cancer cells by blocking the cell signaling pathway dependent of integrins. Thus, the ability to control the signaling pathway induced by proteases makes EcTI a useful tool to study cancer models. Several studies have reported the involvement of mitochondrial energy metabolism and formation of reactive oxygen species (ROS) in the processes of differentiation, maintenance, signaling and survival of leukemic cells. The aim of this work is to investigate the mechanisms involved in inhibition viability of the K562 and THP-1 cell lines by EcTI and their oxidative stress state after treatment with the inhibitor. Still, it is our purpose to evaluate the effect of synthetic peptides derived from EcTI reactive site in order to establish the shorter structure responsible for the inhibitory function.