Screening of a drug library for agents that upregulate CD9 or CD81 in RAW264.7 macrophages.

<p>(<b>A</b>) RAW264.7 cells were cultured for 24 h in the absence (V, vehicle alone) and presence of each drug (10 µM). The cells were lysed, and levels of CD9 and CD81 were examined by immunoblotting. Blots of results with fluvastatin (Fluv) and simvastatin (Simv) are shown. Anti-actin blots show that comparable amounts of protein were loaded in each lane. (<b>B</b>) After testing 1,165 drugs, levels of CD9 and CD81 relative to actin were quantified by densitometry. Fold changes of the expression levels compared with vehicle alone were calculated and plotted. Drugs that increased the level of either CD9 or CD81 more than 1.5-fold compared with vehicle alone were regarded as positive. Correlation between fold changes in CD9 and CD81 levels was analyzed using Pearson’s correlation coefficient. (<b>C</b>) RAW264.7 cells were cultured in the absence (V) or presence of multiple statins (10 µM) and levels of CD9 and CD81 were examined by immunoblotting. The statins are arranged in order of decreasing lipophilicity. Ceri, cerivastatin; Simv, simvastatin; Fluv, fluvastatin; Ator, atorvastatin; Rosu, rosuvastatin; Prav, pravastatin. (<b>D</b>) RAW264.7 cells were cultured in the absence (shaded histograms) or presence (10 µM) of fluvastatin (open red histograms) and simvastatin (open blue histograms). Surface levels of CD9, CD63, CD81, and the integrin β1 subunit were analyzed by flow cytometry.