Antitumoral effects of Amblyomma sculptum Berlese saliva in neuroblastoma cell lines involve cytoskeletal deconstruction and cell cycle arrest / Efeito antitumoral da saliva do carrapato Amblyomma sculptum Berlese em células de neuroblastoma envolve desconstrução do citoesqueleto e parada do ciclo celular

Abstract The antitumor properties of ticks salivary gland extracts or recombinant proteins have been reported recently, but little is known about the antitumor properties of the secreted components of saliva. The goal of this study was to investigate the in vitro effect of the saliva of the hard tick Amblyomma sculptum on neuroblastoma cell lines. SK-N-SK, SH-SY5Y, Be(2)-M17, IMR-32, and CHLA-20 cells were susceptible to saliva, with 80% reduction in their viability compared to untreated controls, as demonstrated by the methylene blue assay. Further investigation using CHLA-20 revealed apoptosis, with approximately 30% of annexin-V positive cells, and G0/G1-phase accumulation (>60%) after treatment with saliva. Mitochondrial membrane potential (Δψm) was slightly, but significantly (p < 0.05), reduced and the actin cytoskeleton was disarranged, as indicated by fluorescent microscopy. The viability of human fibroblast (HFF-1 cells) used as a non-tumoral control decreased by approximately 40%. However, no alterations in cell cycle progression, morphology, and Δψm were observed in these cells. The present work provides new perspectives for the characterization of the molecules present in saliva and their antitumor properties.

Resumo As propriedades antitumorais de extratos de glândulas salivares de carrapatos ou proteínas recombinantes foram relatadas recentemente, mas pouco se sabe sobre as propriedades antitumorais dos componentes secretados da saliva. O objetivo deste estudo foi investigar o efeito in vitro da saliva bruta do carrapato duro Amblyomma sculptum sobre as linhagens celulares de neuroblastoma. Células SK-N-SK, SH-SY5Y, Be(2)-M17, IMR-32 e CHLA-20 foram suscetíveis à saliva, com redução de 80% na sua viabilidade em comparação com controles não tratados, como demonstrado pelo ensaio de Azul de Metileno. Investigações posteriores utilizando CHLA-20 revelaram apoptose, com aproximadamente 30% de células positivas para anexina-V, e G0/G1 (> 60%) após tratamento com saliva. O potencial de membrana mitocondrial (Δψm) foi reduzido significativamente (p <0,05), e o citoesqueleto de actina foi desestruturado, como indicado pela microscopia de fluorescência. A viabilidade do fibroblasto humano (células HFF-1), usado como controle não tumoral, diminuiu em aproximadamente 40%. No entanto, não foram observadas alterações na progressão do ciclo celular, morfologia e Δψm nestas células. O presente trabalho fornece novas perspectivas para a caracterização das moléculas presentes na saliva e suas propriedades antitumorais.

Arachnids of medical importance in Brazil: main active compounds present in scorpion and spider venoms and tick saliva

Arachnida is the largest class among the arthropods, constituting over 60,000 described species (spiders, mites, ticks, scorpions, palpigrades, pseudoscorpions, solpugids and harvestmen). Many accidents are caused by arachnids, especially spiders and scorpions, while some diseases can be transmitted by mites and ticks. These animals are widely dispersed in urban centers due to the large availability of shelter and food, increasing the incidence of accidents. Several protein and non-protein compounds present in the venom and saliva of these animals are responsible for symptoms observed in envenoming, exhibiting neurotoxic, dermonecrotic and hemorrhagic activities. The phylogenomic analysis from the complementary DNA of single-copy nuclear protein-coding genes shows that these animals share some common protein families known as neurotoxins, defensins, hyaluronidase, antimicrobial peptides, phospholipases and proteinases. This indicates that the venoms from these animals may present components with functional and structural similarities. Therefore, we described in this review the main components present in spider and scorpion venom as well as in tick saliva, since they have similar components. These three arachnids are responsible for many accidents of medical relevance in Brazil. Additionally, this study shows potential biotechnological applications of some components with important biological activities, which may motivate the conducting of further research studies on their action mechanisms.(AU)

Arachnids of medical importance in Brazil: main active compounds present in scorpion and spider venoms and tick saliva

Arachnida is the largest class among the arthropods, constituting over 60,000 described species (spiders, mites, ticks, scorpions, palpigrades, pseudoscorpions, solpugids and harvestmen). Many accidents are caused by arachnids, especially spiders and scorpions, while some diseases can be transmitted by mites and ticks. These animals are widely dispersed in urban centers due to the large availability of shelter and food, increasing the incidence of accidents. Several protein and non-protein compounds present in the venom and saliva of these animals are responsible for symptoms observed in envenoming, exhibiting neurotoxic, dermonecrotic and hemorrhagic activities. The phylogenomic analysis from the complementary DNA of single-copy nuclear protein-coding genes shows that these animals share some common protein families known as neurotoxins, defensins, hyaluronidase, antimicrobial peptides, phospholipases and proteinases. This indicates that the venoms from these animals may present components with functional and structural similarities. Therefore, we described in this review the main components present in spider and scorpion venom as well as in tick saliva, since they have similar components. These three arachnids are responsible for many accidents of medical relevance in Brazil. Additionally, this study shows potential biotechnological applications of some components with important biological activities, which may motivate the conducting of further research studies on their action mechanisms.