Abstract
The chemosensitising effect of the nitroaromatic radiosensitiser misonidazole (MISO) on the alkylating agent cyclophosphamide (CTX) has been investigated in a C3H mammary carcinoma in CDF1 mice. The selective cytotoxicity against aerobic and hypoxic cells was measured indirectly, using a local tumour control (TCD50) assay. The hypoxic fraction was calculated from the dose difference between the TCD50S for tumours irradiated either in air or under clamped conditions. The relative survival of tumour cells after drug therapy was expressed as a surviving fraction (SF). CTX (100 mg kg-1) was found to be considerably more toxic towards hypoxic than aerobic cells (SF 4% versus 52%). MISO (1000 mg kg-1) was almost exclusively toxic to hypoxic cells (SF 22%). When MISO and CTX were administered simultaneously a decrease in the surviving fraction was observed. The effect on aerated cells was found to be 10-fold more than expected from addition of toxicities, suggesting a chemosensitising effect on these cells by MISO when used in combination with CTX. No synergistic effect was found on radiobiologically hypoxic cells. The exact role of hypoxia for the development of chemosensitisation seems to be complex and requires additional research in the future.
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- 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. The mechanisms of cytotoxicity and chemosensitization by misonidazole and other nitroimidazoles. Int J Radiat Oncol Biol Phys. 1982 Mar-Apr;8(3-4):675–682. doi: 10.1016/0360-3016(82)90711-8. [DOI] [PubMed] [Google Scholar]
- Durand R. E., Chaplin D. J. Chemosensitization by misonidazole in CCNU-treated spheroids and tumours. Br J Cancer. 1987 Aug;56(2):103–109. doi: 10.1038/bjc.1987.165. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grau C., Overgaard J. Effect of cancer chemotherapy on the hypoxic fraction of a solid tumor measured using a local tumor control assay. Radiother Oncol. 1988 Dec;13(4):301–309. doi: 10.1016/0167-8140(88)90225-3. [DOI] [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]
- Horsman M. R., Evans J. W., Brown J. M. Enhancement of melphalan-induced tumour cell killing by misonidazole: an interaction of competing mechanisms. Br J Cancer. 1984 Sep;50(3):305–316. doi: 10.1038/bjc.1984.177. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Horsman M. R., Wood P. J., Brown J. M. Misonidazole chemosensitization of EMT6 spheroids to melphalan. Radiother Oncol. 1989 May;15(1):103–114. doi: 10.1016/0167-8140(89)90123-0. [DOI] [PubMed] [Google Scholar]
- Howes A. E. An estimation of changes in the proportions and absolute numbers of hypoxic cells after irradiation of transplanted C3H mousemammary tumours. Br J Radiol. 1969 Jun;42(498):441–447. doi: 10.1259/0007-1285-42-498-441. [DOI] [PubMed] [Google Scholar]
- Martin W. M., McNally N. J., De Ronde J. Enhancement of the effect of cytotoxic drugs by radiosensitizers. Br J Cancer. 1981 Jun;43(6):756–766. doi: 10.1038/bjc.1981.113. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moore B. A., Palcic B., Skarsgard L. D. Radiosensitizing and toxic effects on the 2-nitroimidazole Ro-07-0582 in hypoxic mammation cells. Radiat Res. 1976 Sep;67(3):459–473. [PubMed] [Google Scholar]
- Mulcahy R. T. Effect of oxygen on misonidazole chemosensitization and cytotoxicity in vitro. Cancer Res. 1984 Oct;44(10):4409–4413. [PubMed] [Google Scholar]
- Roizin-Towle L., Hall E. J., Pirro J. P. Oxygen dependence for chemosensitization by misonidazole. Br J Cancer. 1986 Dec;54(6):919–924. doi: 10.1038/bjc.1986.262. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sheldon P. W., Batten E. L. Potentiation in vivo of melphalan activity by nitroimidazole compounds. Int J Radiat Oncol Biol Phys. 1982 Mar-Apr;8(3-4):635–637. doi: 10.1016/0360-3016(82)90701-5. [DOI] [PubMed] [Google Scholar]
- Siemann D. W. Modification of chemotherapy by nitroimidazoles. Int J Radiat Oncol Biol Phys. 1984 Sep;10(9):1585–1594. doi: 10.1016/0360-3016(84)90508-x. [DOI] [PubMed] [Google Scholar]
- Siemann D. W. Potentiation of chemotherapy by hypoxic cell radiation sensitizers--a review. Int J Radiat Oncol Biol Phys. 1982 Jun;8(6):1029–1034. doi: 10.1016/0360-3016(82)90172-9. [DOI] [PubMed] [Google Scholar]
- Smith E., Stratford I. J., Adams G. E. Enhancing effect of pre-treatment of cells with misonidazole in hypoxia on their response to melphalan in air. Br J Cancer. 1982 Jul;46(1):117–126. doi: 10.1038/bjc.1982.173. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Spooner D., Peacock J. H., Stephens T. C. Enhancement of cytotoxic drugs by misonidazole (MISO) in Lewis lung tumors of different sizes, and mouse bone marrow. Int J Radiat Oncol Biol Phys. 1982 Mar-Apr;8(3-4):643–646. doi: 10.1016/0360-3016(82)90703-9. [DOI] [PubMed] [Google Scholar]
- Sutherland R. M., Keng P., Conroy P. J., McDermott D., Bareham B. J., Passalacqua W. In vitro hypoxic cytotoxicity of nitroimidazoles: uptake and cell cycle phase specificity. Int J Radiat Oncol Biol Phys. 1982 Mar-Apr;8(3-4):745–748. doi: 10.1016/0360-3016(82)90726-x. [DOI] [PubMed] [Google Scholar]
- Wheeler K. T., Wallen C. A., Wolf K. L., Siemann D. W. Hypoxic cells and in situ chemopotentiation of the nitrosoureas by misonidazole. Br J Cancer. 1984 Jun;49(6):787–793. doi: 10.1038/bjc.1984.122. [DOI] [PMC free article] [PubMed] [Google Scholar]