Fig. 4.

Combining erlotinib, STAT3 decoy, and gossypol further enhances inhibition of cell viability in SCCHN cells. A, UM-22B cells were plated in 96-well plates, and then they were treated with 5 µM erlotinib, 12.6 nM STAT3 decoy, and 2.67 µM gossypol. Cell counts were performed by trypan blue dye exclusion at 72 h. The combination of erlotinib, STAT3 decoy, and gossypol enhanced inhibition of cell viability compared with STAT3 decoy alone (p = 0.004), erlotinib plus gossypol (p = 0.05), or the combination of erlotinib, mutant control, and gossypol (p = 0.0476). B, similar results were seen with PCI-15B treated with 0.16 µM erlotinib, 38.3 nM STAT3 decoy, and 2.97 µM gossypol (p = 0.004, p = 0.02, and p = 0.008, respectively). Cumulative results are shown from five separate experiments.