Figure 3.

Erlotinib induces apoptosis in cells with acquired resistance to cetuximab. Parental cell line (HP) or cetuximab-resistant cell lines (HC1, HC4, HC8) were plated and allowed to adhere for 24 h prior to treatment with vehicle (DMSO), cetuximab (100 nM) or erlotinib (500 nM or 1 uM) for 48 h prior to Annexin-V analysis via flow cytometry. Annexin-V analysis was described in the materials and methods. Data points are represented as mean ± SEM (n = 3). *p ≤ 0.05, **p ≤ 0.001.