Induction of DNA breaks and apoptosis in crosslink-hypersensitive V79 cells by the cytostatic drug beta-D-glucosyl-ifosfamide mustard.
To study molecular aspects of cytotoxicity of the anticancer drug beta-D-glucose-ifosfamide mustard we investigated the potential of the agent to induce apoptosis and DNA breakage. Since beta-D-glucose-ifosfamide mustard generates DNA interstrand crosslinks, we used as an in vitro model system a pair of isogenic Chinese hamster V79 cells differing in their sensitivity to crosslinking agents. CL-V5B cells are dramatically more sensitive (30-fold based on D(10) values) to the cytotoxic effects of beta-D-glucose-ifosfamide mustard as compared to parental V79B cells. After 48 h of pulse-treatment with the agent, sensitive cells but not the resistant parental line undergo apoptosis and necrosis, with apoptosis being the predominant form of cell death (70 and 20% of apoptosis and necrosis, respectively). Apoptosis increased as a function of dose and was accompanied by induction of DNA double-strand breaks in the hypersensitive cells. Furthermore, a strong decline in the level of Bcl-2 protein and activation of caspases-3, -8 and -9 were observed. The resistant parental cells were refractory to all these parameters. Bcl-2 decline in the sensitive cells preceded apoptosis, and transfection-mediated overexpression of Bcl-2 protected at least in part from apoptosis. From the data we hypothesize that non-repaired crosslinks induced by beta-D-glucose-ifosfamide mustard are transformed into double-strand breaks which trigger apoptosis via a Bcl-2 dependent pathway.
Becker
R
R
Institute of Toxicology, Division of Applied Toxicology, University of Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany. kaina@mail.uni-mainz.de
Ritter
A
A
Eichhorn
U
U
Lips
J
J
Bertram
B
B
Wiessler
M
M
Zdzienicka
M Z
MZ
Kaina
B
B
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D006224:Cricetinae; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D004789:Enzyme Activation / Q000187:drug effects; D005947:Glucose / Q000031:analogs & derivatives; D007069:Ifosfamide / Q000031:analogs & derivatives; D010752:Phosphoramide Mustards / Q000494:pharmacology*
D000970:Antineoplastic Agents; D003432:Cross-Linking Reagents; D010752:Phosphoramide Mustards; C092028:beta-D-glucosylisophosphoramide mustard; D004247:DNA; D020169:Caspases; D005947:Glucose; D007069:Ifosfamide