Identification and characterization of Crotalus durissus terrificus venom antitumoral effect and evaluation of its potential use for tumours detection / Identificação e caracterização do efeito antitumoral da peçonha de Crotalus durissus terrificus e avaliação do seu potencial uso na detecção de tumores

AUTOR(ES)

Marcella Araugio Soares

DATA DE PUBLICAÇÃO

2007

RESUMO

The neoplasms basic knowledge is increasing quickly, however, few advances have been reached in clinical therapy and diagnosis of tumours. For this reason, the development of alternative drugs is relevant in the attempt to improve prognosis and to increase the patients survival. Snake venoms are natural sources of bioactive substances with therapeutically potential. The objective of this work was to identify and to characterise the antitumoral effect of Crotalus durissus terrificus venom (PC) and its fractions, Crotoxin and Crotamine, on brain tumours, as well as, to evaluate its radiosensibilising potential and its applicability for tumours detection in vivo. The results demonstrated that PC possess a powerful antitumoral effect for benign (pituitary adenoma) and malignant (glioblastoma multiforme) tumours with IC50 values of 0,96μg/mL and 2,15μg/mL, respectively. This antitumoral effect is mediated by apoptosis induction; it is cell cycle specific and dependent of extracellular calcium, an important factor for Crotoxin phospholipase A2 activity. Besides being a powerful antitumoral agent, PC also presented an important radiosensibilising effect, increasing in 66% the tumour radiotherapy sensitivity. The PC antitumoral effect can be ascribed, at least partially, to the polypeptides Crotoxin and Crotamine that also induced brain tumours apoptosis. These PC polypeptides specifically interacted with malignant tumours in vitro and demonstrated to be capable to detect tumoral focus in vivo. In spite of the PC known nephrotoxicity and neurotoxicity, acute treatment with its antitumoral dose estabilished in vitro was not found to be toxic for the analysed animals. These results indicate the biotechnological potential of PC as source of templates for pharmaceutical and radiopharmaceutical design for cancer therapy and diagnosis.

ASSUNTO(S)

medicina nuclear neoplasms radiopharmaceuticals técnicas de diagnósticos crotalus terrificus neoplasias cancerologia nuclear medicine diagnostic techniques radiofármacos

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