Fig. 14.

Quiescence reduces the toxicity of EP300 and PI3K chemical inhibitors in tracheobronchial basal cells. A, Knockdown of EP300 inhibits basal cell growth. Basal cells proliferating on plastic were infected overnight with shEP300 #3 and shluc control lentiviruses and selected in puromycin after 24 h for an additional 24 h. Selected cells were then seeded in replicate for growth assays. Following 7–10 days of culture, cell growth was quantified by alamarBlue. Data are plotted relative to control shluc-infected cells, which was assigned a value of 100. Means ± S.E. from triplicate cultures are shown. Significance was calculated using a 2-tailed t test. ***p = 1 × 10⁻⁸. B, Single agent EP300 chemical inhibitor treatment suppresses basal cell growth. Cells were fed every other day with the indicated CBP30 concentration and growth quantified after 7–10 days by alamarBlue. Data are plotted relative to control vehicle-treated cells, which was assigned a value of 100. Means ± S.E. from triplicate cultures are shown. Significance was calculated using a 2-tailed t test. ***p = 0.0002 (10 μm CBP30), 0.00004 (20 μm CBP30). C, Quiescence induced by growth on Transwell filters reduces toxicity of PI3K and EP300 chemical inhibitors on basal cells. Basal cells were cultured either subconfluently on plastic dishes or at confluence on Transwell filters, and were treated with fresh drugs every other day. After 8 days, growth was measured be either alamarBlue (plastic) or counting total cell number (Transwell filters). Data are plotted relative to cultures treated with control vehicle, which was assigned a value of 100. Means ± S.E. from triplicate cultures are shown. Significance was calculated using a 2-tailed t test. ***p = 9.1 × 10–7, *p = 0.03.