L‐Amino Acid Oxidase Isolated from Bothrops pirajai Induces Apoptosis in BCR‐ABL‐Positive Cells and Potentiates Imatinib Mesylate Effect

Abstract

Chronic myeloid leukaemia (CML) is a myeloproliferative disorder characterized by the presence of Philadelphia chromosome and by BCR-ABL1, which encodes the BCR-ABL oncoprotein. Although imatinib mesylate (IM) is effective for CML treatment, patients in accelerated and blastic phases of the disease are often refractory to this therapy, and there are also cases of IM resistance in patients in the chronic phase. Therefore, potential new drugs are being investigated to improve the efficiency of the therapy of CML such as snake venoms and their compounds. In this investigation, Bothrops pirajai L-amino acid oxidase (BpirLAAO-I) effect on normal peripheral blood mononuclear cells (PBMC) and on BCR-ABL + cell line was assessed to explore its potential against leukaemic cells. MTT viability assay, lymphocyte subsets quantification and cell activation markers expression were performed to evaluate BpirLAAO-I effect on normal PBMC. The effect of BpirLAAO-I on HL-60 and HL-60.BCR-ABL cell lines was assessed by apoptosis detection. BpirLAAO-I was able to induce apoptosis in HL-60 and HL-60.BCR-ABL cell lines in a dose-dependent manner, promoted caspases 3, 8 and 9 activation and enhanced IM effect while not affecting the viability of normal cells. In addition, BpirLAAO-I promoted immune cells activation and lymphocytes subsets changes on normal PBMC. The results indicate that BpirLAAO-I induces apoptosis and potentiates IM effect on BCR-ABL + cells.Chronic myeloid leukaemia (CML) is a myeloproliferative disorder characterized by the presence of Philadelphia chromosome (Ph) and by BCR-ABL1 neogene, which encodes BCR-ABL oncoprotein. BCR-ABL presents a constitutive tyrosine kinase (TK) activity which is responsible for the resistance of BCR-ABL-positive cells to apoptosis and CML pathogenesis [1][2][3]. Apoptosis could be triggered by intrinsic (also referred to mitochondrial) and extrinsic pathways. The intrinsic pathway is related to release of cytochrome c from mitochondria followed by caspase-9 and caspase-3 activation [4,5], while extrinsic pathway involves death receptors stimulation followed by caspase-8 and caspase-3 triggering without direct involvement of mitochondria [5][6][7]. Studies showed that BCR-ABL expression in myeloid cells contributes to block intrinsic and extrinsic apoptosis pathways [8,9]. Chronic myeloid leukaemia treatments are chemotherapy (hydroxycarbamide), interferon-a and therapies that modulate antileukaemic immune response such as allogeneic bone marrow transplantation and donor lymphocyte infusion [10,11] and tyrosine kinase inhibitors (TKIs). In 2001, the TKI imatinib mesylate (IM) revolutionized CML treatment, becoming the standard first-line therapy [12]. Imatinib mesylate presents high activity in patients with CML at chronic phase inducing over 95% of complete haematological response and 73% of complete cytogenetic remission [13]. Imatinib mesylate therapy is effective, but imatinib-resistant cell clones have already been described and patients treated in disease advanced phase...

Evaluating the microbicidal, antiparasitic and antitumor effects of CR-LAAO from Calloselasma rhodostoma venom

“…Many SV-LAAOs have been used as tools for understanding different pathophysiological events, since these proteins present numerous biological activities that could be used to benefit humans, such as their antiparasitic, microbicidal and antitumor effects [2,11,12,31]. undulations.…”

Caracterização funcional e estudo dos mecanismos de resposta ao dano celular causado por uma L-aminoácido oxidase de Calloselasma rhodostoma em linhagens celulares humanas

“…Isso se deve ao fato dessas proteínas apresentarem diversas atividades biológicas que podem agir de forma benéfica ao homem, como por exemplo, suas atividades antiparasitárias, microbicidas e antitumoral (IZIDORO et al, 2006;RODRIGUES et al, 2009;SUN et al, 2010;LEE et al, 2011;ALVES-PAIVA et al, 2011;GUO et al 2012;BURIN et al, 2013;VARGAS et al, 2013;MUÑOZ et al, 2014).…”

“…Estudos indicam que LAAOs de peçonhas de serpentes apresentam inúmeros efeitos biológicos e farmacológicos, como indução de apoptose celular, citotoxicidade, indução e inibição de agregação plaquetária, hemorragia, hemólise, edema, atividades bactericida e antiparasitária (DU; CLEMETSON, 2002;SAMEL et al, 2008;ZHONG et al, 2009;SUN et al, 2010;LEE et AL., 2011;NAUMANN et al, 2011;BURIN et al, 2013;MUÑOZ et 2014).…”

“…Considerando que as membranas das células tumorais apresentam maior concentração de lipídio em relação às células normais, especulase que a presença do peróxido de hidrogênio produzido pelas LAAOs tenha ação direta (maior citotoxicidade) sobre a membrana das células tumorais e baixa toxicidade sobre células normais (YANG et al, 2011;BURIN et al, 2013 KIM, 1996;TORII et al, 1997). Desde então, muitos estudos vêm descrevendo o efeito apoptótico das LAAOs em diferentes linhagens celulares (TORII et al, 1997;SOUZA et al, 1999;ANDE et al, 2006;ALVES et al, 2008;RODRIGUES et al, 2009;ALVES-PAIVA et al, 2011;LI LEE et al, 2014) A maioria dessas pesquisas busca em compostos naturais, sejam eles, de origem animal ou vegetal, substâncias ativas contra esses microorganismos (VARGAS et al, 2013).…”

“…vias intrínseca e extrínseca da apoptose (BURIN et al, 2013). A LAAO isolada de O. hannah, também foi capaz de ativar as caspases efetoras 3 e 7, sugerindo a eficiência dessa classe de enzima na ativação do processo de apoptose celular (LI LEE et al, 2014).…”