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Characterizing peptide-mediated DNA internalization in human cancer cells

Anders Wittrup1, Mattias Belting

  • 1Department of Clinical Sciences, Section of Oncology, Lund University, Sweden.

Methods in Molecular Biology (Clifton, N.J.)
|December 17, 2008
PubMed

Insights

Cell penetrating peptides (CPPs) primarily enter cells via endocytosis, not direct membrane crossing. This study details methods to characterize CPP uptake mechanisms and intracellular DNA delivery pathways.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Molecular Delivery Systems

Background:

  • Cell penetrating peptides (CPPs) facilitate intracellular delivery of macromolecular cargos.
  • Evidence suggests CPPs predominantly enter cells via endocytosis, challenging the initial direct membrane penetration hypothesis.
  • The specific endocytic pathway for CPPs remains poorly defined and context-dependent.

Purpose of the Study:

  • To provide detailed protocols for characterizing the endocytosis mechanism of CPP-mediated DNA delivery.
  • To offer methods for quantitative and qualitative assessment of CPP uptake.
  • To investigate the intracellular fate of delivered DNA and the role of dynamin in the uptake process.

Main Methods:

  • Quantitative uptake analysis using fluorescence-assisted cell sorting (FACS).
  • Qualitative uptake assessment via confocal microscopy.
  • Intracellular fate determination through co-localization studies with endosomal markers (transferrin, dextran, caveolin-1).
  • Assessment of dynamin dependence using a dominant-negative dynamin-2 construct.

Main Results:

  • Established protocols for characterizing CPP uptake mechanisms.
  • Demonstrated co-localization of internalized DNA with specific endosomal markers.
  • Provided a method to evaluate the role of dynamin in CPP-mediated DNA delivery.

Conclusions:

  • The provided protocols enable robust characterization of CPP uptake pathways.
  • Understanding CPP endocytosis is crucial for optimizing intracellular delivery strategies.
  • Dynamin plays a significant role in the uptake of DNA-peptide complexes via CPPs.

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