ZnO nanoparticle tracking from uptake to genotoxic damage in human colon carcinoma cells.
Zinc Oxide (ZnO) nanoparticles are widely used both in the industry and in biomedical applications for their chemical and physical nanomaterial properties. It is therefore essential to go in depth into the cytotoxicity mechanisms and interactions between nanomaterials and cells. The aim of this work was to evaluate the dissolution of ZnO nanoparticles and their uptake, from a few minutes after treatments up to 24h. ZnO nanoparticles routes of entry into the human colon carcinoma cells (LoVo) were followed at different times by a thorough ultrastructural investigation and semiquantitative analysis. The intracellular release of Zn(2+) ions by Zinquin fluorescent dye, and phosphorylated histone H2AX (γ-H2AX) expression were evaluated. The genotoxic potential of ZnO nanoparticles was also investigated by determining the levels of 8-hydroxyl-2'-deoxyguanosine (8-oxodG). The experimental data show that ZnO nanoparticles entered LoVo cells by either passive diffusion or endocytosis or both, depending on the agglomeration state of the nanomaterial. ZnO nanoparticles coming into contact with acid pH of lysosomes altered organelles structure, resulting in the release of Zn(2+) ions. The simultaneous presence of ZnO nanoparticles and Zn(2+) ions in the LoVo cells determined the formation of reactive oxygen species at the mitochondrial and nuclear level, inducing severe DNA damage.
Department of Technology and Health, Italian National Institute of Health, Rome, Italy; Institute of Chemical Methodologies, National Research Council (CNR), Rome, Italy.
Maria
M
Condello
Department of Technology and Health, Italian National Institute of Health, Rome, Italy.
Barbara
B
De Berardis
Department of Technology and Health, Italian National Institute of Health, Rome, Italy.
Maria Grazia
MG
Ammendolia
Department of Environment and Primary Prevention, Italian National Institute of Health, Rome, Italy.
Flavia
F
Barone
University of Rome Foro Italico, Department of Movement, Human and Health Sciences, Rome, Italy.
Giancarlo
G
Condello
S.C. Mutagenesis, IRCCS AOU San Martino - IST (Istituto Nazionale per la Ricerca sul Cancro), CBA Torre A2, L.go R. Benzi 10, Genova, Italy.
Paolo
P
Degan
Department of Technology and Health, Italian National Institute of Health, Rome, Italy. Electronic address: stefania.meschini@iss.it.
Stefania
S
Meschini
D000080242:8-Hydroxy-2'-Deoxyguanosine; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004058:Diffusion; D004705:Endocytosis; D006657:Histones / Q000378:metabolism; D006801:Humans; D053768:Metal Nanoparticles / Q000633:toxicity*; D009153:Mutagens / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015034:Zinc Oxide / Q000633:toxicity*
C468783:H2AX protein, human; D006657:Histones; D009153:Mutagens; D017382:Reactive Oxygen Species; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine; D015034:Zinc Oxide
Genotoxicity; Human colon carcinoma cells; Nanoparticles uptake; Oxidative stress; ZnO nanoparticles