EVALUATION OF THE ANTILEUKEMIC EFFECT AND INTERACTION OF SYNTHETIC ANTIMICROBIAL PEPTIDES ON THE ABL1 PROTEIN

Introduction: Chronic Myeloid Leukemia (CML) is a type of myeloproliferative neoplasm characterized by the presence of the Philadelphia chromosome (Ph), t(9;22), leading to the expression of the chimeric oncoprotein BCR-ABL1. The main treatment for CML consists of the use of tyrosine kinase inhibitors, which have various adverse effects and drug resistance mechanisms. The search for new treatments becomes necessary to achieve shorter remission of the malignancy and a better quality of life for patients. The use of antimicrobial peptides (AMPs) has demonstrated a high antitumor potential, through the induction of apoptosis, reduction of cell proliferation, and modulation of the tumor microenvironment. Furthermore, due to their chemical characteristics, AMPs have high specificity, resulting in a reduction in adverse effects. Thus, the repositioning of AMPs emerges as a therapeutic alternative for CML. Objective: The present study aims to evaluate the cytotoxicity and potential interaction of synthetic AMPs with the BCR-ABL1 protein in the CML cell line K-562. Material and methods: Seven AMPs developed by the research group from the plant proteins Mo-CBP3 (chitin-binding protein), Rc-2S-Alb (2S albumin extracted from Ricinus communis seeds), and PepKAA (chitinase from the plant Arabidopsis thaliana) and selected for this study. Initially, the AntiCP server was used to analyze the physicochemical parameters and ProTox 3.0 to predict the toxicity of AMPs. In addition, molecular docking was performed using the Cluspro server with the ABL1 protein in its active form (2GQG), inactive form (2HYY), and with the presence of the T315I mutation (5MO4). Then, the cytotoxicity analysis was performed on the K-562 lineage using the Alamar Blue assay. Results: The 7 AMPs presented significant scores in the analyses of hydrophobicity (-0.34 - -0.13), isoelectric point (8.27-10.3), and electric charge (+1 - +3). Three AMPs were evaluated with class 5 toxicity, while the others ranged between 4 and 5. In the single-dose cytotoxicity assay, only AMPs 3 and 6 presented significant inhibition (p < 0.05), these presented 50% inhibition concentrations (IC50) of 48.31 and 164.8 μg/mL, respectively. Finally, the docking analysis demonstrated that the analyzed AMPs have high interaction energy (-598.0 to -739.4 kcal/mol) and the potential for structural modulation of the analyzed proteins, with RMSD ranging from 0.562 to 0.761. Discussion: The physicochemical parameters were favorable for the interaction between the peptide and the tumor cell, with positive charges, having strong attraction to the plasma membrane. The AMPs evaluated showed cytotoxic potential, with IC50 lower than other AMPs such as γ-thionine (290 μg/mL). In addition, they presented a class 5 toxicity prediction level, being considered safe. Molecular docking allowed the identification of potential targets of clinical interest in CML, demonstrating that AMPs interact with protein kinase ABL1 and alter its structure. Conclusion: Based on the results presented, we conclude that AMPs have significant potential as antileukemic agents, interacting with and modifying the structure of the protein kinase ABL1 and with antitumor potential in vitro. However, additional studies are needed to elucidate their mechanism of action.