Deguelin Induces Apoptosis by Targeting Both EGFR-Akt and IGF1R-Akt Pathways in Head and Neck Squamous Cell Cancer Cell Lines

Figure 5

Inhibition of activated Akt rather than inhibition of activated ERK is associated with deguelin-induced apoptosis in SCC-4 cells. (a) Subconfluent culture was incubated for 24 h in serum-free medium. After the starvation, cells were treated with U0126 (10 M) or LY294002 (50 M) for 1 h, and cells were incubated for 15 min in 10% FBS-containing medium. Whole-cell lysates were extracted and analyzed by Western blot using antibodies against p-Akt, p-ERK, and PARP (c-PARP, cleaved PARP; u-PARP, uncleaved PARP; total PARP, sum of cleaved and uncleaved PARP). Trypan-blue dye exclusion assay was performed to measure cell viability of SCC-4 cells at 24 h after U0126 (10 M) (b) or LY294002 (50 M) (c) treatment. Arrows indicate inoculated cell numbers. Each point represents the mean ± SD from triplicate assay ().

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