Fig. 1.

Bortezomib induces autophagosome formation in HNSCC cells. UMSCC-22A, 1483, and UMSCC-1 cells stably expressing GFP-LC3 were left untreated (A, E, I), or treated for 24 hours with 0.l% DMSO (B, F, J), or for 24 (C, G, K) or 48 (D, H, L) hours with 20 nM bortezomib. Following treatment, cells were fixed in 2% paraformaldehyde, and nuclei were stained with Hoechst 33258. Cells were then observed by confocal fluorescence microscopy. The number of puncta/cell was determined as described in Materials and methods. Columns represent the average number of puncta/cell from 3 independent experiments, and error bars the standard error of the means.