Rescue of SBDS-knockdown slow cell growth with antioxidants. (A) SDS patients and healthy control bone marrow CD34+ cells were plated in duplicates at a density of 1 × 103 cells/1 mL dish with serum-free containing methylcellulose and a cytokine cocktail (SCF, GM-CSF, IL-3, IL-6, G-CSF, and erythropoietin). Additional duplicate cultures were plated in the same conditions, but with N-acetylcysteine or catalase. BFU-E colonies containing 50 or more cells were scored after 14 days under an inverted microscope. (B) SBDS-knockdown and control K562 cells were induced to undergo erythroid differentiation by plating 2 × 104 cells/35-mm dishes with hemin. Replicate cultures were either not treated or treated with N-acetylcysteine 500μM or treated with catalase 500 U/mL and assessed daily for cell numbers by trypan blue exclusion. The cell growth of the SBDS-knockdown K562 cells after 5 days was significantly improved with N-acetylcysteine (P < .05) and catalase (P < .05) treatment.
