DNA-protein, DNA interstrand cross-links induced by camphoramine chloroacetic platinum in vitro

Effects of camphoramine chloroacetic platinum (CCP) on DNA migration and transcription, DNA-protein and DNA interstrand cross-links induced by CCP were investigated by using agarose gel electrophoresis, alkaline elution and enzymatic techniques, respectively. Chromosome break down and migration alteration of DNa modified by CCP were observed. Plasmid pAR 436 DNA transcription was also blocked when the DNA was treated with CCP. The cross-links took place 8 h after HeLa cells were exposed to CCP 10 mumol/L and higher number of cross-links were obtained after treatment with the agent 20 mumol/L. The number of cross-links was also found to be decreased when the cell lysis was digested with proteinase K. These results suggest that CCP can also induce DNA-protein cross links. Enzymatic studies indicated that CCP preferentially attacks guanine in DNA and restriction enzymes are unable to cleave G-platinated at interval of one base to the restriction sequence.