Figure 3.

EGFR-regulated COX-2 production, basolateral release of PGs and mitogenesis in polarized HCA-7 cells. (A) Northern blot of HCA-7 cells grown on Transwell filters in 10% fetal calf serum and then kept in serum-free medium for 24 and 48 h. Two micrograms of poly(A) RNA was probed with cRNA probes for AR and constitutively expressed 1B15. (B) HCA-7 cells, grown on Transwell filters and maintained serum-free for 24 h, were exposed to increasing concentrations of mAb 528, and PGE₂ levels in the basolateral medium were measured by mass spectrometry. (Inset) COX-2 immunoblot of HCA-7 cells under identical starting conditions as control cells that were then treated with mAb 528 (3 μg/ml) for 24 h. (C) Under identical experimental conditions as in B, a 3-h pulse of [³H]thymidine (1 μCi/ml) was administered 21 h after treatment with mAb 528 and trichloroacetic acid-precipitable counts were determined. All experiments were performed in triplicate and repeated at least twice. The mitogenic data were expressed as percent of control. Error bars represent standard deviation.