Nucleocytoplasmic transport blockage by SV40 peptide-modified gold nanoparticles induces cellular autophagy.
Gold nanoparticles modified with the nuclear localization signal from simian virus 40 large T antigen (GNP-PEG/SV40) accumulate on the cytoplasmic side of the nuclear membrane in HeLa cells. Accumulation of GNP-PEG/SV40 around the nucleus blocks nucleocytoplasmic transport and prevents RNA export and nuclear shuttling of signaling proteins. This long-term blockage of nucleocytoplasmic transport results in cell death. This cell death is not caused by apoptosis or necrosis because caspases 3 and 9 are not activated, and the expression of annexin V/propidium iodide is not enhanced in HeLa cells after treatment. Using transmission electron microscopy, autophagosomes and autolysosomes were seen to appear after 72 hours of treatment with GNP-PEG/SV40. Increasing levels of enhanced green fluorescent protein-microtubule-associated protein 1 light chain 3 (EGFP-LC3)-positive punctate and LC3-II confirmed GNP-PEG/SV40-induced autophagy. In SiHa cells, treatment did not induce accumulation of GNP-PEG/SV40 around the nucleus and autophagy. Treating cells with wheat germ agglutinin, a nuclear pore complex inhibitor, induced autophagy in both HeLa and SiHa cells. GNP-PEG/SV40-induced autophagy plays a role in cell death, not survival, and virus-mediated small hairpin RNA silencing of Beclin-1 attenuates cell death. Taken together, the results indicate that long-term blockade of nucleocytoplasmic transport results in autophagic cell death.
Institute of Basic Medical Sciences, National Cheng Kung University, and Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Tsung-Lin
TL
Tsai
Chia-Cheng
CC
Hou
Hao-Chen
HC
Wang
Zih-Syuan
ZS
Yang
Chen-Sheng
CS
Yeh
Dar-Bin
DB
Shieh
Wu-Chou
WC
Su
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D001343:Autophagy / Q000187:drug effects / Q000502:physiology*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D053769:Nanocapsules / Q000737:chemistry*; D009842:Oligopeptides / Q000494:pharmacology*
D053769:Nanocapsules; D009842:Oligopeptides; C402304:SV40 nuclear localization peptide; D006046:Gold