Salivary Gland Extract from Ornithodoros brasiliensis Disrupts Adhesion-Dependent Behavior in Neuroblastoma Cells

Ornithodoros brasiliensis (mouro tick) is a member of the Argasidae family, also known as soft ticks due to the lack of a sclerotized dorsal plate. Tick salivary secretions are a rich source of bioactive molecules capable of modulating host physiological pro­cesses, with emerging relevance in cancer biology. Neuroblastoma is a pediatric malignancy arising from neural crest-derived cells of the sympathetic nervous system. Here, we investigated the effects of a crude salivary gland extract (SGE) from Ornithodoros brasiliensis on neuroblastoma cells. Cellular responses were evaluated through viability, morphology, cytoskeletal organization, adhesion, migration, and clonogenic assays, as well as analyses of apoptosis and neuronal differentiation markers, using SH-SY5Y neuroblastoma cells and fibroblasts exposed to different SGE concentrations. SGE reduced SH-SY5Y cell viability in a concentration-dependent manner, reaching 50–55% at higher concentrations. In contrast, HFF-1 fibroblasts were less sensitive, maintaining over 90% viability at lower and intermediate concentrations. Morphological changes in SH-SY5Y cells were observed as early as 4 h, including reduced spreading, rounding, and decreased cell-substrate contact, accompanied by F-actin disruption. SGE also increased cell detachment from approximately 5% to 25% and impaired re-adhesion. Furthermore, SGE impaired cell migration and reduced colony formation by 20–30%. SGE induced modest apoptosis (approximately 20–25%) and increased the Sub-G1 population without significantly affecting mitochondrial membrane potential. Regarding neuronal markers, SGE reduced nestin and doublecortin expression, while CD44 remained largely unchanged. Ki-67 expression was also reduced, and the overall marker profile partially overlapped with that observed following ATRA treatment. Overall, these findings demonstrate that O. brasiliensis SGE alters adhesion-dependent processes, viability, and clonogenic capacity in neuroblastoma cells, supporting further investigation of its bioactive components.