In Vivo Exposure of Swiss Albino Mice to Chronic Low Dose of Dimethylnitrosamine (DMN) Lowers Poly-ADP-Ribosylation (PAR) of Bone Marrow Cell and Blood Lymphocyte Proteins

Efforts to identify an easy and convenient biomarker of carcinogenesis with potentials of application in mass screening program continue. In a series of investigations on mice exposed to different carcinogens, poly-ADP-ribosylation (PAR) of cellular proteins of different tissues has been shown to be a potential biomarker of carcinogenesis. Because blood based biomarker of carcinogenesis offers significant advantage in its use in a cancer screening program, this investigation was undertaken to find correlations between initiation of carcinogenesis and PAR of bone marrow cell (BMC) and blood lymphocyte (BL) proteins in mice chronically exposed to low dose of dimethylnitrosamine (DMN) for up to four weeks in vivo. The exposure was either alone or in combination with 3-aminobenzamide (3-AB), an inhibitor of PAR. Total PAR of cellular proteins and of histone H1 protein were monitored by slot and Western blot immunoprobe assays, respectively. The PAR of total cellular proteins as well as of histone H1 was down-regulated in duration of exposure dependent manners. The results suggest that BMC and BL mirrored status of PAR in other tissues. This finding opens up the possibility of using PAR as a biomarker of carcinogenesis in a blood based test utilizing immunoprobe assay of cellular PAR.