Quantitation of Macropinocytosis in Cancer Cells

Part of the Methods in Molecular Biology book series (MIMB, volume 1928)


Macropinocytosis has emerged as an important nutrient supply pathway that sustains cell growth of cancer cells within the nutrient-poor tumor microenvironment. By internalizing extracellular fluid through this bulk endocytic pathway, albumin is supplied to the cancer cells, which, after degradation, serves as an amino acid source to meet the high nutrient demands of these highly proliferating cells. Here, we describe a streamlined protocol for visualization and quantitation of macropinosomes in adherent cancer cells grown in vitro. The determination of the “macropinocytic index” provides a tool for measuring the extent to which this internalization pathway is utilized within the cancer cells and allows for comparison between different cell lines and treatments. The protocol provided herein has been optimized for reproducibility and is readily adaptable to multiple conditions and settings.

Key words

Macropinocytosis Macropinosome Quantitation Quantification Cancer Endocytosis Nutrient uptake Membrane ruffles Fluorescence microscopy Macropinocytic index 


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© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Tumor Initiation and Maintenance ProgramNCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery InstituteLa JollaUSA

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