FIG. 1.

(A) CAM (10 μg/ml) inhibits NHBE cell proliferation. NHBE cells were seeded onto 35-mm dishes at a density of 0.2 × 10⁵ on day −1. CAM (10 μg/ml) was added on day 0 (diamonds, solid line), or cells were cultured with growth-supplemented medium only (squares, dotted line). Cells were counted on days 0, 1, 2, 4, and 6 using a hemocytometer, and a cell viability of more than 90% was confirmed by trypan blue dye exclusion. The growth supplements used were 52 μg/ml bovine pituitary extract, 0.5 μg/ml hydrocortisone, 0.5 pg/ml human recombinant epidermal growth factor, 0.5 μg/ml epinephrine, 10 μg/ml transferrin, 5 μg/ml insulin, 0.1 ng/ml retinoic acid, and 6.5 ng/ml triiodothyronine. These experiments were repeated four times. Data are shown as means ± standard deviations. *, P < 0.05; ****, P < 0.0001 compared with the control (Cont). (B) CAM (10 μg/ml) inhibits NHBE cell proliferation in the absence of growth supplements. NHBE cells were seeded onto 35-mm dishes at a density of 0.2 × 10⁵ on day −1, and CAM (10 μg/ml) was added on the following day (day 0) (diamonds, wide dotted line). CAM was added from day 0 to day 2 but withdrawn on day 2 (squares, solid line), or NHBE cells were cultured with medium only (control) (triangle, dotted line). Cells were counted on days 0, 1, 2, 3, and 4 using a hemocytometer. These experiments were repeated four times. Data are shown as means ± SEMs. *, P < 0.05; ##, P < 0.01; ****, P < 0.0001 compared with the control.