Induction of HbF synthesis in K562 cells by HDAC inhibitors.

Cells were treated with increasing concentrations of the HDAC inhibitors TSA, SAHA, HC-toxin, MS-275, apicidin, or solvent only (0 value) for 4 days. HbF was determined from total cellular extracts by ELISA, normalized by total protein concentrations of extracts, and expressed as nanogram HbF per microgram protein (black bars). Cytotoxicity was assessed by counting cell numbers (white bars). Cell numbers were expressed relative to untreated cells (100%). Each experiment was performed at least 4 times, and standard errors were calculated as indicated.