RESUMEN
Scorpion peptides are well known for their pharmaceutical potential on different targets. These include mainly the ion channels which were found to be highly expressed in many diseases, including cancer, auto-immune pathologies and Alzheimer. So far, however, the disintegrin activity had only been characterized for snake venom molecules. Herein, we present the first short peptide, purified from the venom of Buthus occitanus tunetanus, (termed RK) able to inhibit the cell adhesion of Glioblastoma, Melanoma and Rat pheochromocytoma to different extracellular matrix (ECM) receptors. Anti-integrin antibody assay suggests that RK interacts with both α1ß1 and αvß3 with a more pronounced effect for the former. The examination of the primary structure of RK suggests the involvement of two motifs: KSS, analogue to KTS which was characterized for α1ß1 Snake venom disintegrins, and ECD, analogue to RGD which was found to be active on αvß3. To assess their roles in the disintegrin activity of RK, we conducted a computational analysis. The molecular docking study shows that RK involves mainly two segments to interact with the α1ß1 integrin, but the peptide does not implicate the KSS motif in the interaction. The molecular modeling study, suggests the key contribution of the ECD segment in the interaction with αvß3 integrin.
Asunto(s)
Desintegrinas/química , Desintegrinas/metabolismo , Integrina alfa1beta1/metabolismo , Integrina alfaVbeta3/metabolismo , Venenos de Escorpión/química , Secuencia de Aminoácidos , Animales , Adhesión Celular/efectos de los fármacos , Línea Celular Tumoral , Desintegrinas/farmacología , Humanos , Masculino , Ratones , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Conformación ProteicaRESUMEN
Scorpion toxins have been the subject of many studies which explore their pharmacological potential toward diverse molecular targets, known to monitor key mechanisms in cancer such as proliferation, migration and angiogenesis. The few peptides from scorpion venom that have an anti-tumor effect are generally cytotoxic. Herein, we present the first description of a short 14 amino acid peptide (called RK1), purified from the venom of Buthus occitanus tunetanus, with the particular capabilities, among different other scorpion peptides, to inhibit cell proliferation, migration and angiogenesis of U87 (Glioblastoma) and IGR39 (Melanoma). Moreover, RK1 is a first peptide derived from scorpion venom exhibiting a potential anti-tumoral activity with no manifest toxicity. Our results suggest that, in terms of its primary structure, RK1 is unique compared to a variety of known peptides purified from scorpion venoms. In addition, RK1 is the first natural peptide able to abolish completely the proliferation of cancer cells. The Chicken chorioallantoic membrane model revealed that RK1 strongly inhibits ex-vivo vascular growth. RK1 could open new perspective for the pharmaceutical application of short scorpion venom peptides in anticancer activity and may represent the first member of a new group of scorpion peptides.
Asunto(s)
Antineoplásicos/farmacología , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Neovascularización Fisiológica/efectos de los fármacos , Péptidos/farmacología , Venenos de Escorpión/química , Secuencia de Aminoácidos , Animales , Antineoplásicos/química , Antineoplásicos/aislamiento & purificación , Línea Celular Tumoral , Embrión de Pollo , Membrana Corioalantoides/irrigación sanguínea , Membrana Corioalantoides/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Melanocitos/efectos de los fármacos , Melanocitos/patología , Neuroglía/efectos de los fármacos , Neuroglía/patología , Péptidos/química , Péptidos/aislamiento & purificación , EscorpionesRESUMEN
Kbot55 is a 39 amino acid peptide isolated from the venom of the Tunisian scorpion Buthus occitanus tunetanus. This peptide is cross-linked by 3 disulfide bridges and has a molecular mass of 4128.65Da. Kbot55 is very low represented in the venom and thus represents a challenge for biochemical characterization. In this study, Kbot55 has been subjected to a screening on ion channels expressed in Xenopus laevis oocytes. It was found that Kbot55 targets voltage-gated potassium channels with high affinity. Kbot55 shows very low amino acid identity with other scorpion potassium toxins and therefore was considered a bona fide novel type of scorpion toxin. Sequence alignment analysis indicated that Kbot55 is the first representative of the new α-Ktx31 subfamily and therefore was classified as α-Ktx31.1.
Asunto(s)
Péptidos/química , Péptidos/farmacología , Venenos de Escorpión/química , Animales , Disulfuros/química , Masculino , Ratones Endogámicos C57BL , Peso Molecular , Oocitos/efectos de los fármacos , Oocitos/metabolismo , Técnicas de Placa-Clamp , Péptidos/genética , Péptidos/aislamiento & purificación , Canales de Potasio con Entrada de Voltaje/antagonistas & inhibidores , Canales de Potasio con Entrada de Voltaje/metabolismo , Escorpiones/química , Homología de Secuencia de Aminoácido , Pruebas de Toxicidad/métodos , Xenopus laevisRESUMEN
Scorpion toxins are important pharmacological tools for probing the physiological roles of ion channels which are involved in many physiological processes and as such have significant therapeutic potential. The discovery of new scorpion toxins with different specificities and affinities is needed to further characterize the physiology of ion channels. In this regard, a new short polypeptide called Kbot21 has been purified to homogeneity from the venom of Buthus occitanus tunetanus scorpion. Kbot21 is structurally related to BmBKTx1 from the venom of the Asian scorpion Buthus martensii Karsch. These two toxins differ by only two residues at position 13 (R /V) and 24 (D/N).Despite their very similar sequences, Kbot21 and BmBKTx1 differ in their electrophysiological activities. Kbot21 targets KV channel subtypes whereas BmBKTx1 is active on both big conductance (BK) and small conductance (SK) Ca2+-activated K+ channel subtypes, but has no effects on Kv channel subtypes. The docking model of Kbot21 with the Kv1.2 channel shows that the D24 and R13 side-chain of Kbot21 are critical for its interaction with KV channels.