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Mechanisms of toxicity of hepsulfam in human tumor cell lines
D Y Pacheco1, C Cook, J R Hincks
1Laboratory of Pharmacology, AMC Cancer Research Center, Denver, Colorado 80214.
Abstract:
1,7-Heptanediol disulfamate (hepsulfam, NSC 329680) is a new anti-cancer agent which is currently undergoing phase I clinical trials. The mechanism of action of this compound is not clear at this time. We have recently shown that hepsulfam was more toxic to L1210 leukemia cells than was busulfan. Consistent with the difference in toxicity, we found that hepsulfam induced DNA interstrand cross-links in L1210 mouse leukemia cells, whereas busulfan did not. In the present study, we have found that hepsulfam was more cytotoxic to two human leukemia cell lines (HL-60 and K562) and to two human colon carcinoma cell lines (BE and HT-29) than was busulfan. As in L1210 cells, hepsulfam induced a higher level of DNA interstrand cross-links than busulfan. Both compounds induced DNA-protein cross-links. Hepsulfam was also more cytotoxic to the human leukemia cell lines when the concentrations were reduced 10-fold and the duration of drug exposure was increased to 12-h This more accurately reflects the drug exposures that human leukemia cells may encounter in vivo. Under these 12-h drug exposures, hepsulfam was still able to form DNA interstrand and DNA-protein cross-links, whereas busulfan was only able to form DNA-protein cross-links. These results show that busulfan and hepsulfam react with DNA differently and that hepsulfam is a more potent cytotoxic agent.
Insights
1,7-Heptanediol disulfamate (hepsulfam) is a potent anti-cancer agent. Hepsulfam induces DNA interstrand cross-links, unlike busulfan, making it more cytotoxic to leukemia and colon cancer cells.
Area of Science:
- Oncology
- Molecular Biology
- Pharmacology
Background:
- 1,7-Heptanediol disulfamate (hepsulfam) is an emerging anti-cancer agent in Phase I clinical trials.
- Its precise mechanism of action remains unclear.
- Previous studies indicated hepsulfam's higher toxicity to L1210 leukemia cells compared to busulfan.
Purpose of the Study:
- To investigate the cytotoxic effects and DNA-damaging mechanisms of hepsulfam in comparison to busulfan.
- To evaluate hepsulfam's efficacy against human leukemia and colon carcinoma cell lines.
- To assess the impact of prolonged drug exposure on hepsulfam's activity.
Main Methods:
- Comparative cytotoxicity assays using human leukemia (HL-60, K562) and colon carcinoma (BE, HT-29) cell lines.
- Assessment of DNA interstrand and DNA-protein cross-link formation induced by hepsulfam and busulfan.
- Evaluation of drug effects under standard and prolonged exposure conditions (12-h).
Main Results:
- Hepsulfam demonstrated significantly higher cytotoxicity against human leukemia and colon carcinoma cell lines than busulfan.
- Hepsulfam induced substantial DNA interstrand cross-links, whereas busulfan did not.
- Both agents formed DNA-protein cross-links, but hepsulfam maintained DNA interstrand cross-linking activity even under prolonged exposure.
- Hepsulfam exhibited greater potency and a distinct DNA-damaging profile compared to busulfan.
Conclusions:
- Hepsulfam exhibits a distinct mechanism of action compared to busulfan, primarily through the induction of DNA interstrand cross-links.
- Hepsulfam is a more potent cytotoxic agent against leukemia and colon cancer cell lines.
- These findings support hepsulfam's potential as a novel anti-cancer therapeutic with a unique DNA-targeting capability.