Fluorescence Microscopy for ATP Internalization Mediated by Macropinocytosis in Human Tumor Cells and Tumor-xenografted Mice

We developed a reproducible method to visualize the internalization of nonhydrolyzable fluorescent adenosine triphosphate (ATP), an ATP surrogate, with high cellular resolution. We validated our method using independent in vitro and in vivo assays-human tumor cell lines and immunodeficient mice xenografted with human tumor tissue.