Differential activation of p53 by the various adducts of mitomycin C.
Mitomycin C (MC) is a cytotoxic chemotherapeutic agent that causes DNA damage in the form of DNA cross-links as well as a variety of DNA monoadducts and is known to induce p53. The various DNA adducts formed upon treatment of mouse mammary tumor cells with MC as well as 10-decarbamoyl MC (DMC) and 2,7-diaminomitosene (2,7-DAM), the major MC metabolite, have been elucidated. The cytotoxicity of DMC parallels closely that of MC in a number of rodent cell lines tested, whereas 2,7-DAM is relatively noncytotoxic. In this study, we investigate the ability of MC, DMC, and 2,7-DAM to activate p53 at equidose concentrations by treating tissue culture cell lines with the three mitomycins. Whereas MC and DMC induced p53 protein levels and increased the levels of p21 and Gadd45 mRNA, 2,7-DAM did not. Furthermore, MC and DMC, but not 2,7-DAM, were able to induce apoptosis efficiently in ML-1 cells. Therefore the 2,7-DAM monoadducts were unable to activate the p53 pathway. Interestingly, DMC was able to initiate apoptosis via a p53-independent pathway whereas MC was not. This is the first finding that adducts of a multiadduct type DNA-damaging agent are differentially recognized by DNA damage sensor pathways.
Abbas
Tarek
T
Department of Biological Sciences, Institute for Biomolecular Structure and Function, Hunter College and Graduate School, CUNY, New York, NY 10021, USA.
Olivier
Magali
M
Lopez
Jaqueline
J
Houser
Sandra
S
Xiao
Gu
G
Kumar
Gopinatha Suresh
GS
Tomasz
Maria
M
Bargonetti
Jill
J
D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D017931:DNA Primers; D006801:Humans; D020014:K562 Cells; D016685:Mitomycin / Q000494:pharmacology*; D008937:Mitomycins / Q000494:pharmacology*; D011485:Protein Binding; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D017931:DNA Primers; D008937:Mitomycins; D016159:Tumor Suppressor Protein p53; C067795:10-decarbamoylmitomycin C; D016685:Mitomycin; C056707:2,7-diaminomitosene; D004247:DNA