Fig. 1

Combination therapy inhibited EGFR positive cell proliferation. (a) (b) (c) (d) Endothelial growth factor receptor positive cells were treated with BBR combined with erlotinib for 48 h, and cell viability was determined using the MTT assay. Data are expressed in terms of the percent of control cells (DMSO treated) as the mean ± SEM of 3 replicates. (e) Q-value. The Q-value was calculated using King’s formula. (f) Colony formation assay was used to determine the inhibitory effect of BBR combined with erlotinib on A431 cells. Representative images of colonies from 60-mm plates in the colony formation assay. (g) Quantification of the colony number of A431 cells. Data were analyzed using one-way ANOVA, ^#P < 0.05; ^##P < 0.01; ^###P < 0.001 vs. control. ^*P < 0.05; ^**P < 0.01; ^***P < 0.001 vs. combination-therapy group, ^&P < 0.05; ^&&P < 0.01; ^&&&P < 0.001 vs. erlotinib