RESUMO
Ticks are blood-feeding arthropods that secrete anticoagulant molecules to maintain the fluidity of the blood during its feeding. Tick saliva has many compounds with biological activities that interact directly with host systems, such as blood clotting, platelet aggregation, cell death, among others. Some reportsshow that there are proteins with anticancer properties in tick saliva. This paper reports some of the biological roles of the Amblyomma cajennense tick saliva, including Factor Xa and thrombin inhibition, action on platelet aggregation, and also preliminary cytotoxic effects on tumor cell lines. The crude saliva was tested in the coagulation, fibrinolysis and platelet aggregation systems. The protein profile of the crude saliva was examined through anion exchange chromatography performed in a FPLC system. The chromatography separated seven protein fractions (Pools I to VII), which biological activities wereevaluated. Moreover, the cytotoxic effects of the crude saliva were evaluated on SK-MEL-28 (melanomacells) and MIA PaCa-2 (pancreas adenocarcinoma cells) using the MTT assay, flow cytometry andfluorescence microscopy. The crude saliva was able to induce cell death on both cancer cells lines, and, interestingly, the cytotoxic effects were not observed on human fibroblasts, which were used as control.The present work opens perspectives for the characterization and development of new moleculesinvolved in the hemostatic system and in cancer control.
Assuntos
Carrapatos/parasitologia , Inibidores de Proteases/análise , Toxicidade/análise , Cromatografia Líquida/métodos , SalivaRESUMO
Lonomia obliqua caterpillar is frequently seen in accidents with humans especially in the south of Brazil. Patients develop a hemorrhagic syndrome that can be treated with specific antilonomic serum. A consumptive coagulopathy was found to be the main cause of bleeding complications observed in patients after contact with L. obliqua. Studies revealed that L. obliqua caterpillar bristle extract (LOCBE) displays a procoagulant activity that leads to intravascular thrombin formation, resulting in a special form of disseminated intravascular coagulation (DIC). Fibrinolysis seems to be secondary to the fibrin production, since no direct fibrinolytic activity was found in LOCBE. Two procoagulant toxins, a factor X activator (Losac) and a prothrombin activator (Lopap), were isolated from LOCBE and characterized. Infusion of Lopap into experimental animals triggered a condition similar to that observed in human envenomation