Aim To evaluate the antitumor activity of dianhydrogalactitol ( DAG) in vitro, and further clarify its underlying mechanisms. Methods The inhibitory effect of DAG in NCI-H460 cells was detected by CCK-8 assay and colony formation assay. The morphology of cells treated with DAG was observed under optical mi-croscope. Nuclear morphology was captured by fluores-cence microscopy after Hoechst 33342 staining. Real-time PCR was used to analyze the expression level of topoisomerase Ⅱ ( Topo Ⅱ) mRNA. The protein ex-pression level of Topo Ⅱ was detected by Western blot. Additionally, molecular docking approaches were used to predict the interaction between DAG and TopoⅡ. Results DAG exhibited potent antitumor activity in NCI-H460 cells, and inhibited cell proliferation per-sistently. DAG obviously induced nuclear morphologi-cal changes of NCI-H460 cells. Furthermore, DAG could down-regulate the mRNA and protein expression level of Topo Ⅱ detected by Real-time PCR analysis and Western blot, respectively. Molecular docking predicted that DAG could bind to Topo Ⅱ. Conclu-sion DAG can significantly inhibit the proliferation of NCI-H460 cells, and its underlying mechanisms may involve the down-regulation of Topo Ⅱ mRNA and di-rect binding to Topo Ⅱ, leading to cancer cell death.

Objective To study the prevalence and sequence homology of virulence genes exoU and exoS in 53 strains of pan-drug-resistant Pseudomonas aeruginosa .Methods The virulence genes exoU and exoS were detected by PCR.Sequence homo-logy was analyzed by BOX-PCR.Results Of the 53 clinical isolates of pandrug-resistant Pseudomonas aeruginosa ,the exoS+/exoU- genotype was identified in 40 strains,exoU+/exoS - genotype in 10 strains,exoS +/exoU+ genotype in 1 strain, and exoS-/exoU- genotype in 2 strains.BOX-PCR results showed that 41 exoS+ isolates belonged to 24 genotypes,and 11 exoU+ strains could be grouped into 7 genotypes.Conclusions The prevalence of virulence genes is high in clinical isolates of pandrug-resistant Pseudomonas aeruginosa .BOX-PCR fingerprint analysis combined with sequence homology analysis is help-ful for effective monitoring and control of hospital pandrug-resistant pseudomonas aeruginosa infection.