Dual effects of nitric oxide on radiation induced cellular apoptosis and DNA double strand breaks in tumor cells
SU Xiaoming
CUI Di
REN Ye
CHEN Fang
MA Huizhen
DAI Zhuojie
WANG Zongye
Abstract：Objective To investigate the effects of different concentrations of nitric oxide ( NO) on apoptosis and DNA double strand breaks in tumor cells with different p 53 gene status .Methods The experiment was carried out in the labo-ratory of radiation medicine , The Fourth Military Medical University from June 2009 to June 2010 .The p53 of human non-small cell lung cancer H1299 cells, stably transfected with wild-type or mutant p53 (wtp53) p53 (mp53) gene, H1299/wtp53 or H1299/mp53 cells.Analysis by RT-PCR and restriction fragment length polymorphism expression vectors in the cells was stable ( RFLP) detection method .The cells were cultured in medium containing different concentrations of isosorbide dini -trate (ISDN), and then received X-ray irradiation.After irradiation, apoptosis and gamma H2AX were measured by Ho-echst33342 staining and flow cytometry , respectively .The expression of apoptosis related protein was detected by Western blot.Results In H1299/wtp53 and H1299/mp53 cells, observed a clear band of 110 bp RT products can be PCR in exon 7 of the p53 gene.Exon 7 of p53 gene with MspI or BsrI restriction endonuclease digestion specificity , corresponding in H1299/wtp53 or H1299/mp53 cells, can clearly observe the band of 70 bp.In H1299/wtp53 cells, the low concentration of ISDN (5 μmol/L) can significantly reduce the X-ray radiation induced apoptosis and DNA double strand breaks , whereas high con-centrations of ISDN ( 500 μmol/L ) was significantly increased apoptosis and DNA X-ray radiation induced double strand breaks.Furthermore,nitric oxide has bidirectional effects on radiation-induced Caspase 3 and Bax mediated apoptosis .Howev-er,for these concentrations of ISDN ,none of these phenomena were observed in H 1299/mp53 cells.Conclusion In tumor cells, changes of nitric oxide at different concentrations can be dual effects of radiation induced Bax and Caspase 3 mediated apopto-sis and DNA double strand breaks , and nitric oxide through the regulation of p 53 gene expression to affect cell fate .
Keywords：Nitric oxideIonizing radiationp53ApoptosisDNA double stand break
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 389-394 )