, 1997). Moore et al. (1994) have shown that cecropins are active against several mammalian lymphomas and leukemias in vitro, and a preliminary in vivo study showed that cecropin B increases the survival time of mice bearing murine ascitic colon adenocarcinoma cells. Chen et al. (1997) synthesized cecropin B-1 (CB-1) by replacing the C-terminal segment of CB (positions 26 to 35, the hydrophobic GW3965 order a-helix) with the sequence of CB from positions 1 to 10 (part of the amphipathic α-helix). In addition, cecropin B-2 (CB-2) was generated with the same sequence as CB-1 but including

an extra inserted residue pair of Gly–Pro immediately after Pro 24. These two novel synthesized cecropins exhibited a cytotoxicity that was

shown to be 2–3 times higher than the natural molecule on a leukemia cell line. The role of CB-1 as an antitumoral agent was also reported by Wu et al. (2009), who showed that CB-1 displays low in vivo hemolytic GW572016 activity. Results suggest that CB-1 may be administered intravenously for anti-tumor treatment in the future. Besides, that same study showed that CB-1 has low toxicity on non-tumor cells, as opposed to its activity on cells from leukemia, stomach carcinoma and lung cancer, on which the peptide displayed high toxicity. Suttmann et al. (2008) showed that cecropin A and B inhibit the viability and proliferation of bladder cancer cells, but with no effect on fibroblasts. The selective anti-tumor action mechanism of these peptides depends on disruption of target cell membranes resulting in irreversible cytolysis and cell destruction. Both peptides may offer novel therapeutic strategies Cediranib (AZD2171) for the treatment of bladder cancer with limited cytotoxic effects on benign cells. Our research group has been studying the venom of the caterpillar Lonomia obliqua (Lepidoptera, Saturniidae), also known as taturana

or fire caterpillar ( Veiga et al., 2001). L. obliqua is responsible for causing a hemorrhagic syndrome in humans that accidentally get in touch with its urticating spines. Besides local pain and dermatitis, this hemorrhagic syndrome includes a severe bleeding disorder, renal complications, intracerebral hemorrhage and eventually death ( Duarte et al., 1996 and Kelen et al., 1995). Many active principles from the venom of L. obliqua have been isolated and characterized, including fibrinogenases ( Pinto et al., 2006 and Veiga et al., 2003), hyaluronidases ( Gouveia et al., 2005), a phospholipase A2 ( Seibert et al., 2006), a factor X activator ( Alvarez Flores et al., 2006), a prothrombin activator ( Reis et al., 2001) and an antiapoptotic protein ( Souza et al., 2005). Using another approach, Veiga et al. (2005) studied the proteome and the transcriptome of L.