Issue 36, 2019

Fluorescent probes towards selective cathepsin B detection and visualization in cancer cells and patient samples

Abstract

Human cysteine cathepsins constitute an 11-membered family of proteases responsible for degradation of proteins in cellular endosomal–lysosomal compartments as such, they play important roles in antigen processing, cellular stress signaling, autophagy, and senescence. Moreover, for many years these enzymes were also linked to tumor growth, invasion, angiogenesis and metastasis when upregulated. Individual biological roles of each cathepsin are difficult to establish, because of their redundancy and similar substrate specificities. Selective chemical tools that enable imaging of individual cathepsin activities in living cells, tumors, and the tumor microenvironment may provide a better insight into their functions. In this work, we used HyCoSuL technology to profile the substrate specificity of human cathepsin B. The use of unnatural amino acids in the substrate library enabled us to uncover the broad cathepsin B preferences that we utilized to design highly-selective substrates and fluorescent activity-based probes (ABPs). We further demonstrated that Cy5-labeled MP-CB-2 probe can selectively label cathepsin B in eighteen cancer cell lines tested, making this ABP highly suitable for other biological setups. Moreover, using Cy5-labelled MP-CB-2 we were able to demonstrate by fluorescence microscopy that in cancer cells cathepsins B and L share overlapping, but not identical subcellular localization.

Graphical abstract: Fluorescent probes towards selective cathepsin B detection and visualization in cancer cells and patient samples

Supplementary files

Article information

Article type
Edge Article
Submitted
27 Feb 2019
Accepted
29 Jul 2019
First published
31 Jul 2019
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2019,10, 8461-8477

Fluorescent probes towards selective cathepsin B detection and visualization in cancer cells and patient samples

M. Poreba, K. Groborz, M. Vizovisek, M. Maruggi, D. Turk, B. Turk, G. Powis, M. Drag and G. S. Salvesen, Chem. Sci., 2019, 10, 8461 DOI: 10.1039/C9SC00997C

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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