A real-time cell-binding assay reveals dynamic features of STxB-Gb3 cointernalization and STxB-mediated cargo delivery into cancer cells.

João Crispim Encarnação, Valeria Napolitano, Giulia Opassi, U Helena Danielson, Grzegorz Dubin, Grzegorz M Popowicz, Hélène Munier-Lehmann, Jos Buijs, Karl Andersson, Hanna Björkelund

FEBS letters 2020 Aug

filter terms:

The interaction between the Shiga toxin B-subunit (STxB) and its globotriaosylceramide receptor (Gb3) has a high potential for being exploited for targeted cancer therapy. The primary goal of this study was to evaluate the capacity of STxB to carry small molecules and proteins as cargo into cells. For this purpose, an assay was designed to provide real-time information about the StxB-Gb3 interaction as well as the dynamics and mechanism of the internalization process. The assay revealed the ability to distinguish the process of binding to the cell surface from internalization and presented the importance of receptor and STxB clustering for internalization. The overall setup demonstrated that the binding mechanism is complex, and the concept of affinity is difficult to apply. Hence, time-resolved methods, providing detailed information about the interaction of STxB with cells, are critical for the optimization of intracellular delivery. © 2020 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

Citation

João Crispim Encarnação, Valeria Napolitano, Giulia Opassi, U Helena Danielson, Grzegorz Dubin, Grzegorz M Popowicz, Hélène Munier-Lehmann, Jos Buijs, Karl Andersson, Hanna Björkelund. A real-time cell-binding assay reveals dynamic features of STxB-Gb3 cointernalization and STxB-mediated cargo delivery into cancer cells. FEBS letters. 2020 Aug;594(15):2406-2420