Study on molecular biomarker of DNA lesion induced by nitrogen mustard

  Objective   To assess the feasibility of expression level of Growth arrest and DNA damage (Gadd) genes function as molecular biomar ker of DNA lesion induced by nitrogen mustard, according to the toxicity mechanism of alkylating agents.

  Methods   The human liver tumor HepG2 cells were first treated with nitrogen mustard, the mRNA level of Gadd45, Gadd53, Gadd34 genes were determined by RT-PCR.Meanwhile the single cell gel electrophoresis (comet assay) was applied to determine the DNA damage induced by varying doses of nitrogen mustard and the 3-(4, 5-methylthiozol-2-yl)-2, 5-diphenylte-trazolium bromide (MTT) metabolic viability assay was performed to assess the cytotoxicity of nitrogen mustard.

  Results   Treated with 1 ng/μl nitrogen mustard for different time, expression of Gadd genes increased from 3h to 24h and then decreased gradually.Treated with 1 ng/μl and 5 ng/μl nitrogen mustard respectively for 24 h, expression of Gadd genes had a tendency with from rising to inhibiting.With the concentration of nitrogen mustard increased, damaged cells increased (r_s=0.591, P < 0.01).Treatment with nitrogen mustard of varying concentration (0.5 ng-40 ng/μl) decreased cell viability from 97% to 52% respectively.

  Conclusion   It is possible of expression level of Gadd genes to function as molecular biomarker of DNA damage induced by nitrogen mustard.