Figure 6.

MAPK and p21 regulated the effects of single and combined treatment of gefitinib and JNJ. OVCAR3 cells were pre-transfected with either empty plasmid or p53^R248Q plasmid before treatment with various doses of gefitinib (10, 20 or 30 μM), JNJ (5, 10, or 15 μM), or gefitinib + JNJ (2 + 2, 4 + 4, or 8 + 8 μM) for 24 h. (A) The level of p-MAPK was significantly reduced with increasing doses of gefitinib. The dosage-dependent inhibition of p-MAPK displayed an even more profound effect in the p53^R248Q-overexpression group. The level of p21 was upregulated in both groups with increasing doses of gefitinib. The dosage-dependent upregulation of p21 was not significantly different between the two groups. (B) With increasing doses of JNJ, the level of p-MAPK decreased slightly in the plasmid-only group, while sustained level of p-MAPK was detected in the p53^R248Q-overexpression group. The level of p21 was upregulated significantly with increasing doses of JNJ. Despite the lower level of p21 in the DMSO control of the p53^R248Q-overexpression group, the dosage-dependent upregulation of p21 was greater in the p53^R248Q-overexpression group than in the plasmid-only group. (C) With increasing doses of the gefitinib–JNJ combination, the level of p-MAPK significantly decreased in the plasmid-only group, but not in the p53^R248Q-overexpression group. Moreover, the level of p21 increased with a profound effect in the plasmid-only group, but not in the p53^R248Q-overexpression group. GAPDH expression was measured to serve as a loading control.