Walker 256 Tumor Growth Suppression by Crotoxin Involves Formyl Peptide Receptors and Lipoxin A₄

Abstract

We investigated the effects of Crotoxin (CTX), the main toxin of South American rattlesnake (Crotalus durissus terrificus) venom, on Walker 256 tumor growth, the pain symptoms associated (hyperalgesia and allodynia), and participation of endogenous lipoxin A4. Treatment with CTX (s.c.), daily, for 5 days reduced tumor growth at the 5th day after injection of Walker 256 carcinoma cells into the plantar surface of adult rat hind paw. This observation was associated with inhibition of new blood vessel formation and decrease in blood vessel diameter. The treatment with CTX raised plasma concentrations of lipoxin A4 and its natural analogue 15-epi-LXA4, an effect mediated by formyl peptide receptors (FPRs). In fact, the treatment with Boc-2, an inhibitor of FPRs, abolished the increase in plasma levels of these mediators triggered by CTX. The blockage of these receptors also abolished the inhibitory action of CTX on tumor growth and blood vessel formation and the decrease in blood vessel diameter. Together, the results herein presented demonstrate that CTX increases plasma concentrations of lipoxin A4 and 15-epi-LXA4, which might inhibit both tumor growth and formation of new vessels via FPRs.

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.…”

Walker-256 Tumor: Experimental Model, Implantation Sites and Number of Cells for Ascitic and Solid Tumor Development

“…After euthanasia, the cells are harvested from the abdominal cavity, centrifuged, resuspended in phosphate-saline buffered, saline solution or Hank's balanced saline solution and performed the cell viability test by the Trypan blue exclusion assay in Neubauer's chamber. Subsequently, the cells are inoculated into a second animal intraperitoneally, until the application the cells need to be refrigerated 6,10,27,31,44,45 .…”

“…The implant is performed after the Trypan blue exclusion test in the Neubauer chamber. The cells are resuspended in phosphate-saline buffer, saline solution or Hank's balanced saline and applied at the sites determined by the studies 6,10,13,27,45 added the antibiotic cell suspension (benzylpenicillin and benzetacil) in order to avoid microbial contamination.…”

“…However, it case diverse collateral effects and are not efficient in complete remission of tumor. Therefore, several studies are developed searching for new substances that can substitute the conventional method 4,5,6,7,8,9,10,11 . Thus, it is necessary to use experimental models that corresponds more to the reality of individuals affected by this disease.…”

Crotoxin from Crotalus durissus terrificus venom: In vitro cytotoxic activity of a heterodimeric phospholipase A2 on human cancer-derived cell lines

“…The antitumor and antiproliferative activity of CTX in different cancer cell lines including leukemia, cervix, ovarian, lung, colon, renal, melanoma, and brain has been assessed in in vitro and in vivo studies. According to these studies, the antiproliferative activity occurs through apoptotic mechanisms, triggered by changes in mitochondrial membrane potential, cytochrome C release, and caspase-3 activation (Corin et al, 1993;Newman et al, 1993;Costa et al, 1998;Brigatte et al, 2016). CTX may also induce cell death by activation of autophagy mechanisms, which was demonstrated in breast tumor cells (Yan et al, 2007).…”