Effects of alkylating metabolites of ifosfamide and its bromo analogues on DNA of HeLa cells.
The in vitro cytotoxicity and mechanism of action of three alkylating compounds: an active metabolite of ifosfamide (1, isophosphoramide mustard, N,N'-bis(2-chloroethyl)phosphorodiamidic acid) and its bromo substituted analogues, 2 (one chlorine atom replaced by bromine atom) and 3 (two chlorine atoms replaced by bromine atoms), were studied in cultured HeLa cells. Alkaline elution analysis of cellular DNA demonstrated the presence of concentration- and time-dependent interstrand crosslinks, DNA-protein crosslinks and alkali-labile sites (ALSs) in HeLa cells following a 1 hr exposure to the compounds. The bromo analogues were more cytotoxic than 1 and exhibited higher crosslinking potency. The time-course of crosslink formation and removal for the three compounds was similar. ALSs in DNA were produced by all tested drugs but 3 exhibited exceptionally high activity and was able to induce two kinds of alkali-labile lesion (fast- and slow-appearing) whereas 1 and 2 generated only slow-appearing ones. The results suggest that 1 and 2 are more specific in their reaction with DNA in that they produced a lesser variety of lesions than 3. A potential advantage of 2 over 1 seems to be its higher DNA interstrand crosslinking activity.
Studzian
K
K
Department of General Chemistry, Institute of Physiology and Biochemistry, School of Medicine, Lodz, Poland.
Kinas
R
R
Ciesielska
E
E
Szmigiero
L
L
D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003432:Cross-Linking Reagents; D004273:DNA, Neoplasm / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006367:HeLa Cells / Q000187:drug effects*; D006801:Humans; D007069:Ifosfamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D010752:Phosphoramide Mustards / Q000494:pharmacology
D003432:Cross-Linking Reagents; D004273:DNA, Neoplasm; D010752:Phosphoramide Mustards; C072580:isophosphamide bromide mustard; C027061:isophosphamide mustard; C073801:bromofosfamide; D007069:Ifosfamide