FIGURE 2.

Benzo[a]pyrene induces ABCB6 and ALAS1 expression in a dose- and time-dependent manner. Exposure to B[a]P induces Abcb6 and Alas1 expression in mouse primary hepatocytes (left panels; A and B) and human hepatomas (left panels; C–F) in a dose-dependent (left panels; A, C, and E) and time-dependent manner (left panels; B, D, and F). Right panels (A–F), B[a]P-mediated induction of CYP1A1. CYP1A1, a gene known to be induced by B[a]P in liver, is used as a positive control in these experiments. G, ABCB6 protein expression in response to B[a]P treatment in human hepatomas. ABCB6 expression was measured in isolated mitochondria using an ABCB6-specific antibody. Values represent mean ± S.D. (error bars) (n = 4). Results shown are representative of three independent experiments with n = 4/experiment. *, significantly different from cells exposed to 2.5 μm B[a]P in dose-dependent studies and significantly different from cells exposed to B[a]P for 4 h (hepatomas) in time-dependent studies (p < 0.01). #, significantly different from cells treated with 5 μm B[a]P in dose-dependent studies and significantly different from 8-h treatment (hepatomas) in time-dependent studies (p < 0.01).