Figure 1.

Study design. Single-drug exposures: 48 h after seeding, cells were exposed to ZD1839 alone for 96 h (condition ZD1839); 48 h after seeding, cells were exposed to medium alone for 48 h, followed by cisplatin–5FU for a further 48 h (condition CPFU). Drug combination: 48 h after seeding, CAL33 cells were exposed to ZD1839 (ZD) alone at its IC₅₀ (6 μM) for 48 h, then exposed to cisplatin and 5FU at their IC₃₀'s in combination with ZD1839 for a further 48 h (condition ZDCPFU).