Figure 1.

Autophagy signaling is involved in NTS-mediated HNC cell death. (A) FaDu and SNU1041 cells were treated with or without NTS for the indicated times in the absence of serum and then each protein level was determined with western blots. (B) NTS induced accumulation of GFP-MAP1LC3-II puncta. The GFP-MAP1LC3-II plasmid was transfected into FaDu cells. After 24 h, NTS treatment was given for the indicated times and GFP-MAP1LC3-II puncta were analyzed by fluorescence microscopy (scale bar: 20 μm). GFP-MAP1LC3-II puncta were observed by fluorescence microscopy in 5 fields captured randomly and the GFP-MAP1LC3-II puncta-positive cells were counted (n = 3; scale bar: 20 μm). Data are means ± SD. Asterisks indicate statistically significant differences (P < 0.05). (C) TEM analysis in NTS-treated cells. FaDu cells were treated with NTS for 24 h, and then autophagic vesicles were observed by TEM (N, nucleus; scale bar: 5,000 nm).