Figure 5
Involvement of E2F1 in cell growth promotion by nicotine. (A) Left panel: ChIP analysis of nicotine-treated MCF10A cells in the presence or absence of dn-src, PD168393, AG1478 or KP372-1. Sonicated, cross-linked chromatin was immunoprecipitated with an anti-E2F1 antibody, and the purified DNA was assayed by PCR with the primers for cdc25A promoter. Right panels: After the same treatments as described above, cell lysates were prepared and subjected to immunoblotting with the anti-phosphor-E2F antibody. (B) After different treatments, [3H]thymidine incorporation in the cells was measured. (C) After being serum-starved for 24 hours, the cells were cultured in the medium containing 0.5% serum plus various inhibitors, and the numbers of viable cells were counted for 4 days. Error bars represent SD (standard deviation), n = 5.