Anti-tumor activity of CrTX in human lung adenocarcinoma cell line A549

Abstract

Aim: To assess the cytotoxic effect of crotoxin (CrTX), a potent neurotoxin extracted from the venom of the pit viper Crotalus durissus terrificus, in human lung adenocarcinoma A549 cells and investigated the underlying mechanisms. Methods: A549 cells were treated with gradient concentrations of CrTX, and the cell cycle and apoptosis were analyzed using a flow cytometric assay. The changes of cellular effectors p53, caspase-3 and cleaved caspase-3, total P38MAPK and pP38MAPK were investigated using Western blot assays. A549 xenograft model was used to examine the inhibition of CrTX on tumor growth in vivo. Results: Treatment of A549 cells with CrTX (25-200 μg/mL) for 48 h significantly inhibited the cell growth in a dose-dependent manner (IC 50 =78 μg/mL). Treatment with CrTX (25 μg/mL) for 24 h caused G1 arrest and induced cell apoptosis. CrTX (25 μg/mL) significantly increased the expression of wt p53, cleaved caspase-3 and phospho-P38MAPK. Pretreatment with the specific P38MAPK inhibitor SB203580 (5 μmol/L) significantly reduced CrTX-induced apoptosis and cleaved caspase-3 level, but G 1 arrest remained unchanged and highly expressed p53 sustained. Intraperitoneal injection of CrTX (10 μg/kg, twice a week for 4 weeks) significantly inhibited A549 tumor xenograft growth, and decreased MVD and VEGF levels. Conclusion: CrTX produced significant anti-tumor effects by inducing cell apoptosis probably due to activation of P38MAPK and caspase-3, and by cell cycle arrest mediated by increased wt p53 expression. In addition, CrTX displayed anti-angiogenic effects in vivo.

Interactions of PLA2-s from Vipera lebetina, Vipera berus berus and Naja naja oxiana Venom with Platelets, Bacterial and Cancer Cells

“…Crotoxin, a noncovalent complex (formed by two nonidentical subunits: a basic PLA 2 crotoxinB and a nonenzymatic acidic crotoxinA) isolated from the venom of Crotalus durissus terrificus, exhibits a preferential cytotoxic activity against various types of tumor cells including K-562 cells [58], MCF-7 cells [59] and lung adenocarcinoma A549 cells. Treatment of A549 cells with crotoxin significantly inhibited the cell growth in a dose-dependent manner and displayed anti-angiogenic effects in vitro [60]. Crotoxin has been used in the treatment of different advanced carcinomas [61].…”

Crotoxin induces apoptosis and autophagy in human lung carcinoma cells in vitro via activation of the p38MAPK signaling pathway

“…We have recently reported that CrTX-induced cell apoptosis in human lung adenocarcinoma A549 cells by activating p38MAPK and caspase-3. We have also demonstrated CrTXinduced cell cycle arrest mediated by increased wt p53 expression and p-JNK up-regulation in SK-MES-1 cells [24,25] . However, the molecular mechanisms involved in the inhibition of SK-MES-1 cells, specifically the effect of p38 on the induction of apoptosis and autophagy, are not well characterized.…”

Neuromuscular paralysis by the basic phospholipase A 2 subunit of crotoxin from Crotalus durissus terrificus snake venom needs its acid chaperone to concurrently inhibit acetylcholine release and produce muscle blockage

“…Despite the neurotoxicity, several studies have pointing towards other biological activities of CTX that have potential pharmacological value such as immunomodulatory, anti-nociceptive, anti-inflammatory, anti-tumoral and anti-microbial activities (Sampaio et al, 2010;Favoretto et al, 2011;Ye et al, 2011;Wang et al, 2012;He et al, 2013;Han et al, 2014;Almeida et al, 2015;Brigatte et al, 2016;Faure et al, 2016). Thus, a more complete understanding of the neurotoxic action of CTX is relevant not only to improve the treatment of envenomation, but also to enable the biotechnological use of this toxin or new drugs derived from this protein.…”