Abstract
The ability of a range of 2-nitroimidazoles with similar electron affinities but widely differing partition coefficients (P) to enhance the cytotoxicity of cyclophosphamide (CY) in mouse tumour and normal tissues was investigated. In a preliminary study large single doses of benznidazole (BENZ), misonidazole (MISO), desmethylmisonidazole (DMM), and SR-2508 were found to give similar enhancement of the RIF-1 and SCC VII/St tumours. SR-2555 was less effective. A direct comparison was made between MISO and SR-2508 using prolonged, low-level drug exposures, achieved by multiple injections. The enhancement of CY cytotoxicity achieved in the two tumour systems (RIF-1 and SCC VII/St) was found to be similar for a given blood sensitizer concentration. In the normal tissue assays (white blood cell count, bone marrow CFU-S and testis spermatogonia) neither MISO nor SR-2508 produced significant enhancement of CY cytotoxicity, so that the therapeutic gains achieved at a given blood concentration of sensitizer were similar for SR-2508 and MISO. The main advantage of SR-2508, however, will probably lie in its lower toxicity, permitting higher blood levels to be achieved. However, the slope of the dose response curves are rather shallow so we would not predict a dramatically increased benefit.
Full text
PDFSelected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brown D. M., Gonzalez-Mendez R., Brown J. M. Factors influencing intracellular uptake and radiosensitization by 2-nitroimidazoles in vitro. Radiat Res. 1983 Mar;93(3):492–505. [PubMed] [Google Scholar]
- Brown J. M., Hirst D. G. Effect of clinical levels of misonidazole on the response of tumour and normal tissues in the mouse to alkylating agents. Br J Cancer. 1982 May;45(5):700–708. doi: 10.1038/bjc.1982.111. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brown J. M., Twentyman P. R., Zamvil S. S. Response to the RIF-1 tumor in vitro and in C3H/Km mice to X-radiation (cell survival, regrowth delay, and tumor control), chemotherapeutic agents, and activated macrophages. J Natl Cancer Inst. 1980 Mar;64(3):605–611. [PubMed] [Google Scholar]
- Conroy P. J., McNeill T. H., Passalacqua W., Merritt J., Reich K. R., Walker S. Nitroimidazole neurotoxicity: are mouse studies predictive? Int J Radiat Oncol Biol Phys. 1982 Mar-Apr;8(3-4):799–803. [PubMed] [Google Scholar]
- Hinchliffe M., McNally N. J., Stratford M. R. The effect of radiosensitizers on the pharmacokinetics of melphalan and cyclophosphamide in the mouse. Br J Cancer. 1983 Sep;48(3):375–383. doi: 10.1038/bjc.1983.202. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hirst D. G., Brown J. M., Hazlehurst J. L. Enhancement of CCNU cytotoxicity by misonidazole: possible therapeutic gain. Br J Cancer. 1982 Jul;46(1):109–116. doi: 10.1038/bjc.1982.172. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hirst D. G., Brown J. M. The therapeutic potential of misonidazole enhancement of alkylating agent cytotoxicity. Int J Radiat Oncol Biol Phys. 1982 Mar-Apr;8(3-4):639–642. doi: 10.1016/0360-3016(82)90702-7. [DOI] [PubMed] [Google Scholar]
- Law M. P., Hirst D. G., Brown J. M. Enhancing effect of misonidazole on the response of the RIF-1 tumour to cyclophosphamide. Br J Cancer. 1981 Aug;44(2):208–218. doi: 10.1038/bjc.1981.172. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee F. Y., Workman P. Modification of CCNU pharmacokinetics by misonidazole--a major mechanism of chemosensitization in mice. Br J Cancer. 1983 May;47(5):659–669. doi: 10.1038/bjc.1983.104. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lu C. C., Meistrich M. L. Cytotoxic effects of chemotherapeutic drugs on mouse testis cells. Cancer Res. 1979 Sep;39(9):3575–3582. [PubMed] [Google Scholar]
- McNally N. J., Hinchliffe M., de Ronde J. Enhancement of the action of alkylating agents by single high, or chronic low doses of misonidazole. Br J Cancer. 1983 Aug;48(2):271–278. doi: 10.1038/bjc.1983.182. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Siemann D. W. Response of murine tumours to combinations of CCNU with misonidazole and other radiation sensitizers. Br J Cancer. 1982 Feb;45(2):272–281. doi: 10.1038/bjc.1982.43. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TILL J. E., McCULLOCH E. A. A direct measurement of the radiation sensitivity of normal mouse bone marrow cells. Radiat Res. 1961 Feb;14:213–222. [PubMed] [Google Scholar]
- Taylor Y. C., Evans J. W., Brown J. M. Mechanism of sensitization of Chinese hamster ovary cells to melphalan by hypoxic treatment with misonidazole. Cancer Res. 1983 Jul;43(7):3175–3181. [PubMed] [Google Scholar]
- Twentyman P. R., Brown J. M., Gray J. W., Franko A. J., Scoles M. A., Kallman R. F. A new mouse tumor model system (RIF-1) for comparison of end-point studies. J Natl Cancer Inst. 1980 Mar;64(3):595–604. [PubMed] [Google Scholar]
- Urtasun R., Band P., Chapman J. D., Feldstein M. L., Mielke B., Fryer C. Radiation and high-dose metronidazole in supratentorial glioblastomas. N Engl J Med. 1976 Jun 17;294(25):1364–1367. doi: 10.1056/NEJM197606172942503. [DOI] [PubMed] [Google Scholar]
- Workman P., Brown J. M. Structure-pharmacokinetic relationships for misonidazole analogues in mice. Cancer Chemother Pharmacol. 1981;6(1):39–49. doi: 10.1007/BF00253009. [DOI] [PubMed] [Google Scholar]
- Workman P., Twentyman P. R. Enhancement by electron-affinic agents of the therapeutic effects of cytotoxic agents against the KHT tumor: structure-activity relationships. Int J Radiat Oncol Biol Phys. 1982 Mar-Apr;8(3-4):623–626. doi: 10.1016/0360-3016(82)90698-8. [DOI] [PubMed] [Google Scholar]
- Workman P., Twentyman P. R. Structure/activity relationships for the enhancement by electron-affinic drugs of the anti-tumour effect of CCNU. Br J Cancer. 1982 Aug;46(2):249–259. doi: 10.1038/bjc.1982.190. [DOI] [PMC free article] [PubMed] [Google Scholar]