Cytotoxic and pro-apoptotic action of MjTX-I, a phospholipase A2 isolated from Bothrops moojeni snake venom, towards leukemic cells

Abstract

BackgroundChronic myeloid leukemia (CML) is a BCR-ABL1+ myeloproliferative neoplasm marked by increased myeloproliferation and presence of leukemic cells resistant to apoptosis. The current first-line therapy for CML is administration of the tyrosine kinase inhibitors imatinib mesylate, dasatinib or nilotinib. Although effective to treat CML, some patients have become resistant to this therapy, leading to disease progression and death. Thus, the discovery of new compounds to improve CML therapy is still challenging. Here we addressed whether MjTX-I, a phospholipase A2 isolated from Bothrops moojeni snake venom, affects the viability of imatinib mesylate-resistant Bcr-Abl+ cell lines.MethodsWe examined the cytotoxic and pro-apoptotic effect of MjTX-I in K562-S and K562-R Bcr-Abl+ cells and in the non-tumor HEK-293 cell line and peripheral blood mononuclear cells, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and the hypotonic fluorescent solution methods, associated with detection of caspases 3, 8, and 9 activation and poly (ADP-ribose) polymerase (PARP) cleavage. We also analyzed the MjTX-I potential to modulate the expression of apoptosis-related genes in K562-S and K562-R cells.ResultsMjTX-I decreased the viability of K562-S and K562-R cells by 60 to 65%, without affecting the viability of the non-tumor cells, i.e. it exerted selective cytotoxicity towards Bcr-Abl+ cell lines. In leukemic cell lines, the toxin induced apoptosis, activated caspases 3, 8, and 9, cleaved PARP, downregulated expression of the anti-apoptotic gene BCL-2, and upregulated expression of the pro-apoptotic gene BAD.ConclusionThe antitumor effect of MjTX-I is associated with its potential to induce apoptosis and cytotoxicity in Bcr-Abl positive cell lines sensitive and resistant to imatinib mesylate, indicating that MjTX-I is a promising candidate drug to upgrade the CML therapy.

BthTX-I from Bothrops jararacussu induces apoptosis in human breast cancer cell lines and decreases cancer stem cell subpopulation

“…Some PLA 2 s from snakes belonging to the genus Bothrops exert antineoplastic action, such as myotoxin-II from Bothrops asper that is cytotoxic to adrenal tumor, and MjTX-II from Bothrops moojeni venom that is cytotoxic to Ehrlich ascites tumor, SKBR3 breast adenocarcinoma, and Jurkat T-cell leukemia [19]. Furthermore, a prior study found that MjTX-I, a PLA 2 from Bothrops moojeni , is able to diminish cell viability of chronic myeloid leukemia cells (K562-S and K562-R BCR-ABL + ) and induce apoptosis through activation of Caspases 3, 8 and 9 [20]. It remains unclear exactly how bothropstoxins from B. jararacussu affect mammary carcinomas.…”

Cytotoxicity of snake venom enzymatic toxins: phospholipase A2 and l-amino acid oxidase

“…Elevated oxidative stress leads to the activation of cell death pathways. Although there is no establishment of the exact pathways, it might involve the down-regulation of anti-apoptotic proteins such as Bcl2, Bcl-XL and c-FLIP [56]. There is also an increase in pro-apoptotic BAD expression and the activation of caspase 3 [56].…”

“…Although there is no establishment of the exact pathways, it might involve the down-regulation of anti-apoptotic proteins such as Bcl2, Bcl-XL and c-FLIP [56]. There is also an increase in pro-apoptotic BAD expression and the activation of caspase 3 [56]. Moreover, PLA 2 alters the distribution of different phases in the cell cycle to cause apoptosis [57].…”

Effect of Bitis gabonica and Dendroaspis angusticeps snake venoms on apoptosis-related genes in human thymic epithelial cells

“…The cytotoxic and pro-apoptotic effect of snake venoms has been extensively studied due to the possible application of venom-derived components as anti-cancer agents [3][4][5]. The pro-apoptotic effect has been studied from venoms of numerous genera, such as Bitis [6], Bothrops [7][8][9][10], Cerastes [6,11], Echis [12], Lachesis [13], Ophiophagus [14], Naja [15,16] and Walterinessia [17]. Furthermore, the apoptosis inducing effect of individual components isolated from snake venoms has also been studied, demonstrating that L-amino acid oxidases (LAAO) [18][19][20], snake venom metalloproteinases (SVMP) [21,22], disintegrins [23,24] and phospholipases A 2 (PLA 2 ) [9,25] are capable of inducing apoptosis in various cell types.…”

“…The pro-apoptotic effect has been studied from venoms of numerous genera, such as Bitis [ 6 ], Bothrops [ 7 - 10 ], Cerastes [ 6 , 11 ], Echis [ 12 ], Lachesis [ 13 ], Ophiophagus [ 14 ], Naja [ 15 , 16 ] and Walterinessia [ 17 ]. Furthermore, the apoptosis inducing effect of individual components isolated from snake venoms has also been studied, demonstrating that L-amino acid oxidases (LAAO) [ 18 - 20 ], snake venom metalloproteinases (SVMP) [ 21 , 22 ], disintegrins [ 23 , 24 ] and phospholipases A 2 (PLA 2 ) [ 9 , 25 ] are capable of inducing apoptosis in various cell types. Although the apoptotic effect of snake venoms and their components are well characterized, there are still few reports on how these venoms affect other PCD mechanisms.…”