Epigenetic modulation of apoptotic machinery in Bcr-Abl positive cells by BmooLAAO-I and MjTX-I toxins

Abstract

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm cytogenetically characterized by the presence of the Philadelfia (Ph) chromosome and molecularly by the appearance of the BCR-ABL1 neogene that encodes the Bcr-Abl oncoprotein with constitutive tyrosine kinase (TK) activity. Bcr-Abl expression promotes myeloproliferation, decreased hematopoietic cell adhesion to the medullary stroma, and resistance to apoptosis through transformation of the normal hematopoietic cell into leukemic. The treatment of CML can be performed through different therapeutic modalities, including imatinib mesylate (MI), a Bcr-Abl tyrosine kinase inhibitor. Although IM is efficient, patients in advanced stages of the disease and some in the chronic phase are resistant to this therapy, mainly due to the presence of mutations at the Bcr-Abl catalytic site, such as the T315I mutation. In this context, it is necessary to describe new and more efficient therapies for CML. The objective of the present project is to investigate the effect of the toxins L-amino acid oxidase (LAAO) and phospholipase A2 (PLA2) isolated from Bothrops moojeni - BmooLAA-I and MjTX-I (myotoxin PLA2-Lys49) respectively - in the methylation profile of the regulatory genes of apoptosis and in the expression of microRNAs (miRNAs) that target genes that regulate apoptosis. In addition, simultaneous expression of proteins involved in apoptosis and some cell signaling pathways such as STAT-5, MAPK / ERK and PI3K / AKT / mTOR will be evaluated. Studies have shown that LAAOs and PLA2s isolated from snakes can induce various effects of therapeutic interest such as antimicrobial, antiparasitic, antiviral and inducer of cellular apoptosis. The study will be performed on mononuclear cells (MNC) of patients with CML and on the resistant and sensitive MI HL-60 and Bcr-Abl positive cell lines (HL-60.Bcr-Abl, K562-S and K562-R). The data obtained during the development of this project may contribute to the description of new substances for the treatment of CML and substances with potential epigenetic and protein modulators. (AU)