The objective of this study was to investigate whether the conjugation of
gold nanoparticles (GNPs) to 5-
aminolevulinic acid (5-ALA) could enhance the anti-
tumor efficiency of
photodynamic therapy (PDT) in
epidermoid carcinoma cells. The
mRNA and
protein expression levels were determined by
quantitative real-time PCR and
western blot, respectively.
Cell viability,
apoptosis, invasion, and migration were determined by MTT assay,
flow cytometry, transwell invasion assay, and migration assay, respectively.
Singlet oxygen generation was detected by the
singlet oxygen sensor green
reagent assay. Our results showed that PDT with 5-ALA and GNPs-conjugated 5-ALA (5-ALA-GNPs) significantly suppressed
cell viability, increased
cell apoptosis and
singlet oxygen generation in both HaCat and A431
cells, and PDT with 5-ALA and 5-ALA-GNPs had more profound effects in A431
cells than that in
HaCat cells. More importantly, 5-ALA-GNPs
treatment potentiated the effects of PDT on
cell viability,
cell apoptosis, and
singlet oxygen generation in A431
cells compared to 5-ALA
treatment. Further
in vitro assays showed that PDT with 5-ALA-GNPs significantly decreased expression of STAT3 and Bcl-2 and increased expression of Bax in A431
cells compared with PDT with 5-ALA. In addition, 5-ALA-GNPs
treatment enhanced the inhibitory effects of PDT on
cell invasion and migration and Wnt/β-
catenin signaling activities in A431
cells compared to 5-ALA
treatment. In conclusion, our results suggested that GNPs conjugated to 5-ALA significantly enhanced the anti-
tumor efficacy of PDT in A431
cells, which may represent a better strategy to improve the outcomes of
patients with cutaneous
squamous cell carcinoma.