Abstract A73: GD3 ganglioside-enriched extracellular vesicles stimulate melanocyte migration

Abstract

Abstract Gangliosides are sialic acid-containing glycosphingolipids located mainly in outlet membrane plasma. Tumors usually accumulate gangliosides as disialoganglioside GD3 which is widely expressed in melanomas and neuroblastomas. GD3 has been associated with tumor progression, conferring tumorigenic characteristics to cells such as increased proliferation and migration. In order to investigate the role of GD3 in cell migration, we have transfected the GD3 synthase gene (ST8Sia I) in a melanocyte cell line. In this work we have demonstrated that overexpression of GD3 upon transfection of GD3 synthase was associated with an increased migratory response towards laminin-1. GD3 and 9-O-acetyl-GD3 gangliosides, which colocalize with integrins in cell lamellipodia, are positive modulators of integrin function in the migratory response while GD3 was left behind as a molecular footprint. Indeed, addition of exogenous GD3 to the cells stimulated cell migration whereas exogenously added GM3 inhibited it. However, depletion of gangliosides using a glucosylceramide synthase inhibitor led cells more migratory. Glycosphingolipids content modulates FGF-2-induced cell migration as we demonstrated that FGF-2 induces cell migration. However, this effect was abolished after using glucosylceramide synthase inhibitor, suggesting that GD3 may modulate the motogenic activity of FGF-2. Finally, we showed that GD3 synthase transfected melanocytes release extracellular vesicles (EVs) enriched in GD3. These EVs are responsible for modulating cell migration response due to increase average velocity of GD3 negative cells as we showed in a real-time wound-healing assay. This study shows that EVs from a subset of GD3 positive cells may contribute to the horizontal signaling propagation to a different subset of GD3 negative cells. Thus, data present here led us to an important insight into how EVs carrying GD3 ganglioside could participate in intercellular communication modulating cellular migration. Citation Format: Andreia H. Otake, Ana Paula M. Duarte, Renata de Freitas Saito, Alexandre F. Ramos, Roger Chammas. GD3 ganglioside-enriched extracellular vesicles stimulate melanocyte migration [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr A73.