Cancer Chemotherapy and Pharmacology

, Volume 33, Issue 5, pp 410–414 | Cite as

Induction of apoptosis in murine tumors by cyclophosphamide

  • Raymond E. Meyn
  • L. Clifton Stephens
  • Nancy R. Hunter
  • Luka Milas
Original Articles Apoptosis, Cyclophosphamide, Murine Tumors


Whereas there have been several recent reports of the induction of apoptosis by chemotherapy agents in cell culture systems, much less is known about the role of this mode of cell death in tumors treated in vivo. We therefore quantitated the proportion of apoptotic cells induced as a function of time and dose in two murine tumors treated with cyclophosphamide in vivo. The two tumors were a mammary adenocarcinoma, MCa-4, and an ovarian adenocarcinoma, OCa-1. The percent apoptosis was scored from stained histological sections of the tumors using a system based on the characteristic features of the apoptotic nuclei. The kinetics of apoptosis development were determined over a 5-day period following treatment of the mice with 200 mg/kg. The percent apoptosis peaked between 10–18 h in both tumors and then slowly declined to background levels by 5 days after treatment. The dose responses showed that even much lower doses, 25 mg/kg, could induce significant apoptosis and that the proportion of apoptotic cells plateaued at doses higher than 100 mg/kg. These results are compared and contrasted with our previous reports on apoptosis induction in these same tumors with ionizing radiation.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Arends MJ, Wyllie AH (1991) Apoptosis: mechanisms and roles in pathology. Int Rev Exp Pathol 32: 223Google Scholar
  2. 2.
    Barry MA, Behnke CA, Eastman A (1990) Activation of programmed cell death (apoptosis) by cisplatin, other anticancer drugs, toxins and hyperthermia. Biochem Pharmacol 40: 2353Google Scholar
  3. 3.
    Cohen JJ, Duke RC (1984) Glucocorticoid activation of calcium-dependent endonuclease in thymocyte nuclei leads to cell death. J Immunol 132: 38Google Scholar
  4. 4.
    Duvall E, Wyllie AH (1986) Death and the cell. Immunol Today 7: 115Google Scholar
  5. 5.
    Eastman A (1990) Activation of programmed cell death by anticancer agents: cisplatin as a model system. Cancer Cells 2: 275Google Scholar
  6. 6.
    Falkvoll KH (1991) Quantitative histological changes in a human melanoma xenograft following exposure to single dose irradiation and hyperthermia. Int J Radiat Oncol Biol Phys 21: 989Google Scholar
  7. 7.
    Kaufmann SH (1989) Induction of endonucleolytic DNA cleavage in human actute myelogenous leukemia cells by etoposide, camptothecin, and other cytotoxic anti-cancer drugs: a cautionary note. Cancer Res 49: 5870Google Scholar
  8. 8.
    Kyprianou N, English HF, Isaacs JT (1990) Programmed cell death during regression of PC-82 human prostate cancer following androgen ablation. Cancer Res 50: 3748Google Scholar
  9. 9.
    Kyprianou N, English HF, Davidson NE, Isaacs JT (1991) Programmed cell death during regression of the MCF-7 human breast cancer following estrogen ablation. Cancer Res 51: 162Google Scholar
  10. 10.
    McConkey DJ, Nicotera P, Hartzell P, Bellomo G, Wyllie AH, Orrenius S (1989) Glucocorticoids activate a suicide process in thymocytes through an elevation of cytosolic Ca++ concentration. Arch Biochem Biophys 269: 365Google Scholar
  11. 11.
    Meyn RE, Stephens LC, Ang KK, Hunter N, Milas L, Peters LJ (1993) Heterogeneity in apoptosis development in irradiated murine tumors. Int J Radiat Biol (in press)Google Scholar
  12. 12.
    Milas L, Ito H, Hunter N (1983) Effect of tumor size on S-2-(3-aminopropylamino) ethylphosphorothioic acid and misonidazole alteration of tumor response to cyclophosphamide. Cancer Res 43: 3050Google Scholar
  13. 13.
    Searle J, Lawson TA, Abbott PJ, Harmon B, Kerr JFR (1975) An electron-microscope study of the mode of cell death induced by cancer chemotherapeutic agents in populations of proliferating normal and neoplastic cells. J Pathol (Lond) 116: 129Google Scholar
  14. 14.
    Sellins KS, Cohen JJ (1987) Gene induction by γ-irradiation leads to DNA fragmentation in lymphocytes. J Immunol 139: 3199Google Scholar
  15. 15.
    Stephens LC, Schultheiss TE, Small SM, Ang KK, Peters LJ (1989) Response of parotid organ culture to radiation. Radiat Res 120: 140Google Scholar
  16. 16.
    Stephens LC, Ang KK, Schultheiss TE, Milas L, Meyn RE (1991) Apoptosis in irradiated murine tumors. Radiat Res 127: 308Google Scholar
  17. 17.
    Stephens LC, Hunter NR, Ang KK, Milas L, Meyn RE (1993) Development of apoptosis in irradiated murine tumors as a function of time and dose. Radiat Res 135: 75Google Scholar
  18. 18.
    Story MD, Stephens LC, Tomasovic SP, Meyn RE (1992) A role for calcium in regulating apoptosis in rat thymocytes irradiated in vitro. Int J Radiat Biol 61: 243Google Scholar
  19. 19.
    Wyllie AH (1985) The biology of cell death in tumors. Anticancer Res 5: 131Google Scholar
  20. 20.
    Wyllie AH (1992) Apoptosis and the regulation of cell numbers in normal and neoplastic tissues: an overview. Cancer Metast Rev 11: 95Google Scholar
  21. 21.
    Wyllie AH, Kerr JFR, Currie AR (1980) Cell death: the significance of apoptosis. Int Rev Cytol 68: 251Google Scholar
  22. 22.
    Yamada T, Ohyama H (1988) Radiation-induced interphase death of rat thymocytes is internally programmed (apoptosis). Int J Radiat Biol 53: 65Google Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • Raymond E. Meyn
    • 1
  • L. Clifton Stephens
    • 2
  • Nancy R. Hunter
    • 1
  • Luka Milas
    • 1
  1. 1.Department of Experimental RadiotherapyThe University of Texas M. D. Anderson Cancer CenterHoustonUSA
  2. 2.Department of Veterinary Medicine and SurgeryThe University of Texas M. D. Anderson Cancer CenterHoustonUSA

Personalised recommendations