Enhanced reactive oxygen species overexpression by CuO nanoparticles in poorly differentiated hepatocellular carcinoma cells (original) (raw)
* Corresponding authors
a Department of Chemistry, National Sun Yat-sen University, Kaohsiung 804, Taiwan
E-mail: shsieh@facmail.nsysu.edu.tw
b Department of Seafood Science, National Kaohsiung Marine University, Kaohsiung 811, Taiwan
c Department of Nutrition and Health Science, Chang Jung Christian University, Tainan 711, Taiwan
d Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung 804, Taiwan
e Department of Surgery, E-DA Hospital, Kaohsiung 82445, Taiwan
f Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
g Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
h Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
i School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan
Abstract
Copper oxide nanoparticles (CuO NPs) are known to exhibit toxic effects on a variety of cell types and organs. To determine the oxidative impact of CuO NPs on hepatocellular carcinoma (HCC) cells, well-differentiated (HepG2) and poorly differentiated (SK-Hep-1) cells were exposed to CuO NPs. Cell viability assay showed that the median inhibition concentration (IC50) for SK-Hep-1 and HepG2 cells was 25 μg ml−1 and 85 μg ml−1, respectively. Cellular fluorescence intensity using DCFH-DA staining analysis revealed significant intracellular reactive oxygen species (ROS) generation of up to 242% in SK-Hep-1 cells, compared with 86% in HepG2 cells. HPLC analysis demonstrated that a CuO NP treatment caused cellular GSH depletion of 58% and a GSH/GSSG ratio decrease to ∼0.1 in SK-Hep-1 cells. The oxidative stress caused by enhanced superoxide anion production was observed in both HepG2 (146%) and SK-Hep-1 (192%) cells. The Griess assay verified that CuO NPs induced NO production (170%) in SK-Hep-1 cells. Comet assay and western blot further demonstrated that CuO NPs induced severe DNA strand breakage (70%) in SK-Hep-1 cells and caused DNA damage via increased γ-H2AX levels. These results suggest that well-differentiated HepG2 cells possess a robust antioxidant defense system against CuO NP-induced ROS stress and exhibit more tolerance to oxidative stress. Conversely, poorly differentiated SK-Hep-1 cells exhibited a deregulated antioxidant defense system that allowed accumulation of CuO NP-induced ROS and resulted in severe cytotoxicity.
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Article information
DOI
https://doi.org/10.1039/C4NR05843G
Article type
Paper
Submitted
05 Oct 2014
Accepted
28 Nov 2014
First published
01 Dec 2014
Download Citation
Nanoscale, 2015,7, 1820-1829
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Enhanced reactive oxygen species overexpression by CuO nanoparticles in poorly differentiated hepatocellular carcinoma cells
M. Kung, S. Hsieh, C. Wu, T. Chu, Y. Lin, B. Yeh and S. Hsieh,Nanoscale, 2015, 7, 1820DOI: 10.1039/C4NR05843G
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