Objective To explore the relationship between intracellular concentration of arsenic trioxide (ATO) in ATO-resistant K562 cells (K562/AS2) and ATO resistance level.Methods The K562/AS2 cells were established by gradually increasing the concentration of ATO from the parental cell line,K562.Arsenic concentration was measured with atomic fluorescence photometry.Cell viability was assessed using MTT assay.Results At exposure to 1 μg/ml ATO for 24 h,48 h and 72 h,the arsenic concentration in the K562/S cells were all significantly higher than that in the K562/AS2 cells,(15.63± 0.42) μg/L vs 0 μg/L,(22.27±0.15) μg/L vs (3.51±0.12) μg/L and (24.31±0.21) μg/L vs (3.61±0.11) μg/L (P ＜ 0.05).With increasing concentration and the extension of incubation time,concentration of arsenic in cells was gradually increased (P ＜ 0.05),which increase quickly between 1 μg/ml and 2 μg/ml.The growth inhibition rate of K562/AS2 cells was also gradually increased (P ＜ 0.05),which increased quickly between 1 μg/ml and 2 μg/ml.Linear correlation analysis showed that when the K562/AS2 cells was exposed to ATO for 24 h,48 h and 72 h,respectively,the cell growth inhibition rates were positively correlated with the intracellular concentration of ATO.Conclusions Either increasing concentrations of ATO or prolonging the exposure time to ATO can increase intracellular concentration of ATO in ATO-resistant cells,and intracellular arsenic concentration is positively related to the cytotoxicity of ATO to K562/AS2 cells.Therefore,the sensitivity to ATO of ATOresistant K562 cells could be restored by increasing the intracellular concentration of ATO.

Objective:To explore the significance of next-generation sequencing to detect gene mutations for diagnosis of patients with unexplained pancytopenia.Methods:The next-generation sequencing was used to detect 32 common hematological tumor gene mutations in 113 patients with unexplained pancytopenia in Huazhong University of Science and Technology Union Shenzhen Hospital from February 2016 to February 2019.Results:The next-generation sequencing results showed that of the 32 genes tested in 113 patients, 69 mutations occurred in 25 genes. Among them, 105 patients (92.9%) carried at least 1 gene mutation, and the median number of mutations was 2 (1-5). Fifty-one patients were diagnosed with myelodysplastic syndrome (MDS), and the related mutant genes were detected; 62 patients were diagnosed with atypical aplastic anemia or cytopenia of unknown significance. The total effective rate of treatment for 113 patients was 65.5% (74/113).Conclusion:The next-generation sequencing helps to diagnose patients with unexplained pancytopenia, and provides targeted strategies for finding new treatments and prolonging the overall survival of patients.