Zinc oxide nanoparticles induce photocatalytic cell death in human head and neck squamous cell carcinoma cell lines in vitro.
The aim of this study was to determine the photocatalytic effects of zinc oxide (ZnO) NPs in combination with UVA-1 in human head and neck squamous cell carcinoma (HNSCC) cell lines in vitro. NP characteristics and intracellular distribution were described by transmission electron microscopy (TEM). After pre-incubation with ZnO NPs in concentrations of 0.002-20 µg/ml, the HNSCC cell lines HLaC 78 and UD-SCC 7A as well as primary oral mucosa cells (pOMCs) were treated with UVA-1. Cell survival and vitality was observed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide-(MTT)-assay and fluorescein diacetate test. Apoptosis was assessed by annexin-V propidium iodide flow cytometry. Intranuclear distribution of the rod-shaped particles was observed in 3.5% of HNSCC and in 0.5% of pOMCs. UVA-1 irradiation of 15 min in combination with 0.2 and 2 µg/ml of ZnO NP dispersion was shown to reduce the vitality of cancer cell lines significantly in comparison to cells without NP exposure or UVA-1 treatment only. For HLaC 78, a significant reduction in viable cells was already seen at 10 min of UVA-1 treatment and a ZnO NP concentration of 2 µg/ml. Flow cytometry indicated that cell death occurred primarily through necrosis. In pOMCs, vitality was not influenced either by UVA-1 treatment or ZnO NP exposure up to 2 µg/ml or a combination of both. ZnO NPs showed cytotoxicity at 20 µg/ml without UVA-1. Due to their photocatalytic properties, ZnO NPs may induce cell death in human HNSCC cell lines in vitro. Further studies will evaluate a possible benefit in adjuvant cancer therapy.
Department of Otorhinolaryngology, University of Wuerzburg, 97080 Wuerzburg, Germany.
Stephan
S
Hackenberg
Agmal
A
Scherzed
Michael
M
Kessler
Katrin
K
Froelich
Christian
C
Ginzkey
Christian
C
Koehler
Marc
M
Burghartz
Rudolf
R
Hagen
Norbert
N
Kleinsasser
D002277:Carcinoma / Q000188:drug therapy / Q000473:pathology / Q000648:ultrastructure; D002294:Carcinoma, Squamous Cell; D016923:Cell Death / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D017024:Chemotherapy, Adjuvant; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000648:ultrastructure; D006801:Humans; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000009:adverse effects / Q000627:therapeutic use*; D018307:Neoplasms, Squamous Cell / Q000188:drug therapy / Q000473:pathology / Q000648:ultrastructure; D055668:Photochemical Processes / Q000187:drug effects; D010778:Photochemotherapy / Q000379:methods; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D000077195:Squamous Cell Carcinoma of Head and Neck; D013997:Time Factors; D014466:Ultraviolet Rays; D015034:Zinc Oxide / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*
D017319:Photosensitizing Agents; D015034:Zinc Oxide