Figure 4. Combination effects of ATRA or 9-cis RA and SAHA, SL142 or SL325 on suppression of colony formation in H441 lung cancer cells.
A. Colony formation of H441 cells treated with ATRA or 9-cis RA (2.5 µM) or/and SAHA, SL142 or SL325 (0.5 µM) for 36 hours. The assay was initiated by plating 2×103 cells per 100-mm dishes. After 16 days, cells were fixed and stained with crystal violet. Representative pictures of experiments performed in triplicate are shown. B. Mean colony numbers were derived from quantitation of triplicate dishes for each treatment and percentage-specific cytotoxicity compared to colony formation in the DMSO group (control) was calculated. *, p<0.05 versus single agents.