Effect of High Dose Vitamin C on Proliferation and Apoptosis of Acute Myeloid Leukemia Cells

OBJECTIVE To investigate the effects of high dose vitamin C on proliferation and apoptosis of acute myeloid leukemia (AML) cell lines including HL-60, U937 and primary CD34+ leukemia cells in AML. METHODS CD34+ cells were sorted by using immunomagnetic cell sorting system, then the primary CD34+ leukemia cells, including HL-60 and U937 cell lines were cultured in vitro. Cells in each group were treated with different concentrations of vitamin C, the survival rate of cells was determined by MTT assay, the apoptosis rate of cells was evaluated by Annexin V/PI double staining, the expression of apoptotic proteins-including cleaved caspase 3, cleaved caspase-9 and cleaved PARP were detected by Western blot. RESULTS The proliferation of HL-60 and U937 cells could be inhibited by high dose vitamin C, which showed a concentration-dependent manner (r=-0.9664; r=-0.9796). HL-60 and U937 cells were treated with different concentrations of vitamin C (8 and 20 mmol/L) for 24 hours, respectively, it was found that with the increasing of vitamin C concentration, cell apoptosis rate was significantly increased (r=0.9905; r=0.9971), and the expression of apoptosis related proteins including cleaved caspase 3, cleaved caspase-9 and cleaved PARP was aslo significantly increased with the increasing of concentration. In addition, it was found that with or without the mutation of TET2, high dose vitamin C could inhibit the proliferation (r=-0.9719; r=-0.9699) and promote the apoptosis (r=0.9998; r=0.9901) of primary CD34+ leukemia cells in AML, which showed a dose-dependent manner, but it showed no effect on the proliferation (r=-0.2032) and apoptosis (r=0.1912) of normal CD34+ cells. CONCLUSION High dose vitamin C can inhibit the proliferation and promote the apoptosis of acute myeloid leukemia cells, and selectively kill primary CD34+ leukemia cells in AML.