Epidermal growth factor receptor targeted nuclear delivery and high-resolution whole cell X-ray imaging of Fe3O4@TiO2 nanoparticles in cancer cells.
Sequestration within the cytoplasm often limits the efficacy of therapeutic nanoparticles that have specific subcellular targets. To allow for both cellular and subcellular nanoparticle delivery, we have created epidermal growth factor receptor (EGFR)-targeted Fe3O4@TiO2 nanoparticles that use the native intracellular trafficking of EGFR to improve internalization and nuclear translocation in EGFR-expressing HeLa cells. While bound to EGFR, these nanoparticles do not interfere with the interaction between EGFR and karyopherin-β, a protein that is critical for the translocation of ligand-bound EGFR to the nucleus. Thus, a portion of the EGFR-targeted nanoparticles taken up by the cells also reaches cell nuclei. We were able to track nanoparticle accumulation in cells by flow cytometry and nanoparticle subcellular distribution by confocal fluorescent microscopy indirectly, using fluorescently labeled nanoparticles. More importantly, we imaged and quantified intracellular nanoparticles directly, by their elemental signatures, using X-ray fluorescence microscopy at the Bionanoprobe, the first instrument of its kind in the world. The Bionanoprobe can focus hard X-rays down to a 30 nm spot size to map the positions of chemical elements tomographically within whole frozen-hydrated cells. Finally, we show that photoactivation of targeted nanoparticles in cell nuclei, dependent on successful EGFR nuclear accumulation, induces significantly more double-stranded DNA breaks than photoactivation of nanoparticles that remain exclusively in the cytoplasm.
Department of Radiation Oncology, Northwestern University , Chicago, Illinois 60611, United States.
Ye
Y
Yuan
Si
S
Chen
Tatjana
T
Paunesku
Sophie Charlotte
SC
Gleber
William C
WC
Liu
Caroline B
CB
Doty
Rachel
R
Mak
Junjing
J
Deng
Qiaoling
Q
Jin
Barry
B
Lai
Keith
K
Brister
Claus
C
Flachenecker
Chris
C
Jacobsen
Stefan
S
Vogt
Gayle E
GE
Woloschak
D021581:Active Transport, Cell Nucleus; D002467:Cell Nucleus / Q000378:metabolism*; D020552:Comet Assay; D003593:Cytoplasm / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004337:Drug Carriers / Q000737:chemistry*; D066246:ErbB Receptors / Q000378:metabolism*; D005290:Ferric Compounds / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D008024:Ligands; D053768:Metal Nanoparticles / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D009369:Neoplasms / Q000188:drug therapy*; D014025:Titanium / Q000737:chemistry*; D014965:X-Rays; D028961:beta Karyopherins / Q000737:chemistry
D004337:Drug Carriers; D005290:Ferric Compounds; D008024:Ligands; D028961:beta Karyopherins; C009495:titanium dioxide; C000499:ferric oxide; D014025:Titanium; D066246:ErbB Receptors