OBJECTIVEAcute myeloid leukemia progressed from myelodysplastic syndrome (MDS/AML) is generally incurable with poor prognosis for complex karyotype including monosomy 7 (-7). Qinghuang Powder (, QHP), which includes Qing Dai (Indigo naturalis) and Xiong Huang (realgar) in the formula, is effective in treating MDS or MDS/AML even with the unfavorable karyotype, and its therapeutic efficacy could be enhanced by increasing the Xiong huang content in the formula, while Xiong huang contains > 90% arsenic disulfide (As2S2). F-36p cell line was established from a MDS/AML patient with complex karyotype including -7, and was in cytokine-dependent. The present study was to investigate the effects of As2S2 on F-36p cells.

METHODSCell proliferation was measured by an 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis was identified by Annexin V-staining. Cell viability was determined by a propidium iodide (PI) exclusion. Erythroid differentiation was evaluated by the expression of cell surface antigen CD235a (GpA).

RESULTSAfter treatment with As2S2 at concentrations of 0.5 to 16 μmol/L for 72 h, As2S2 inhibited the proliferation of F-36p cells. The 50% inhibitory concentrations (IC50) of As2S2 against the proliferation of F-36p cells was 6 μmol/L. The apoptotic cells significantly increased in a dose-dependent mannar (P<0.05). The cell viabilities were significantly inhibited by As2S2 dose-dependent in a dose-dependent manner (P<0.05). Significant increases of CD235a-positive cells were concurrently observed (P<0.05) also in a dose-dependent manner.

CONCLUSIONSAs2S2 could inhibit proliferation and viability, induce apoptosis, and concurrently promote erythroid differentiation dose-dependently in F-36p cells. As2S2 can inhibit proliferation and viability, induce apoptosis, and concurrently promote erythroid differentiation in cytokine-dependent MDS-progressed human leukemia cell line F-36p with complex karyotype including -7. The data suggest that QHP and/or As2S2 could be a potential candidate in the treatment of MDS or MDS/AML even with unfavorable cytogenetics.