iScience (Sep 2022)

Monitoring extracellular ion and metabolite dynamics with recombinant nanobody-fused biosensors

  • Sandra Burgstaller,
  • Teresa R. Wagner,
  • Helmut Bischof,
  • Sarah Bueckle,
  • Aman Padamsey,
  • Desiree Frecot,
  • Philipp D. Kaiser,
  • David Skrabak,
  • Roland Malli,
  • Robert Lukowski,
  • Ulrich Rothbauer

Journal volume & issue
Vol. 25, no. 9
p. 104907

Abstract

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Summary: Ion and analyte changes in the tumor microenvironment (TME) alter the metabolic activity of cancer cells, promote tumor cell growth, and impair anti-tumor immunity. Consequently, accurate determination and visualization of extracellular changes of analytes in real time is desired. In this study, we genetically combined FRET-based biosensors with nanobodies (Nbs) to specifically visualize and monitor extracellular changes in K+, pH, and glucose on cell surfaces. We demonstrated that these Nb-fused biosensors quantitatively visualized K+ alterations on cancer and non-cancer cell lines and primary neurons. By implementing a HER2-specific Nb, we generated functional K+ and pH sensors, which specifically stained HER2-positive breast cancer cells. Based on the successful development of several Nb-fused biosensor combinations, we anticipate that this approach can be readily extended to other biosensors and will open new opportunities for the study of extracellular analytes in advanced experimental settings.

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