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Updated: Apr 19, 2026
Fluorescence Microscopy for ATP Internalization Mediated by Macropinocytosis in Human Tumor Cells and Tumor-xenografted Mice
Published on: June 30, 2021
Internalization of Near-Infrared Fluorescently Labeled Activatable Cell-Penetrating Peptide and of Proteins into
Felista Tansi1, Eric Kallweit1,2, Christoph Kaether3
1Institute of Diagnostic and Interventional Radiology, Department of Experimental Radiology, Jena University Hospital, Friedrich-Schiller University, Erlanger Allee 101, Jena, 07747, Germany.
Abstract:
The internalization of near-infrared fluorescently labeled cargos into living cells and tissues allows a highly sensitive detection without interference from skin, porphins or other fluorescent cell and tissue compounds. In this study, the uptake of labeled bovine serum albumin and an antibody, into fibrosarcoma (HT-1080) cells was triggered by the formation of non-covalent complexes with different cell-penetrating peptides; uptake efficiency and intracellular localization were determined. To improve selectivity of internalization into tumor cells, a fluorescent activatable cell-penetrating peptide (ACPP) was synthesized and functionally characterized. This 25-mer peptide was designed to be activatable by Matrix-Metallo-Proteases (MMPs). Its uptake selectivity was estimated using cells with different MMP activities.
