Cancer Chemotherapy and Pharmacology

, Volume 31, Issue 4, pp 259–264 | Cite as

Quantitation of the synergistic interaction of edatrexate and cisplatin in vitro

  • Ting-Chao Chou
  • Queng-Hui Tan
  • Francis M. Sirotnak
Original Articles Edatrexate, Cisplatin, Synergistic Interaction


Cytotoxicity studies combining edatrexate (EDX) and cisplatin (Cis-Pt) were carried out in HL-60 cells in vitro as a retrospective analysis of the same combination in animal models and as a prospective study of this combination for future clinical trials. For purposes of comparison, parallel studies were carried out using methotrexate (MTX) and Cis-Pt. Dose-effect relationships were analyzed by the median-effect principle and the combination index-isobologram technique. EDX was the most cytotoxic agent of the three examined. The doses effective in 50% inhibition of the cell proliferation (ED50 values) for EDX, MTX, and Cis-Pt were 0.001, 0.0043, and 1.08 μm, respectively. Synergism occurred at effect levels corresponding to greater than 65% inhibition of cell growth by EDX+Cis-Pt, with an increase in synergism being observed at high doses. By contrast, MTX+Cis-Pt exhibited moderate synergism, with a decrease in synergism being noted at high doses. Preceding one drug by another for 4 h during the 48-h incubation period did not result in synergism greater than that produced by simultaneous exposure to both drugs for both pairs of combinations. Due to the synergism arising from these combinations, the ED90 values can be reduced by as many as 52 and 7.3 times for Cis-Pt and EDX, respectively, as compared with only 4.0 and 1.9 times for Cis-Pt and MTX, respectively. The calculation of these drug interactions was carried out automatically with the use of computer software and was also illustrated by a sample calculation performed without computer simulation.


Methotrexate Drug Interaction Cytotoxic Agent Effect Level Synergistic Interaction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.





edatrexate, 10-ethyl-10-deaza-aminopterin

Cis-Pt cisplatin



combination index


dose-reduction index


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  1. 1.
    Burchenal JH (1978) A clinical overview of dichlorodiammino platinum. Biochimie (Paris) 60:915–923Google Scholar
  2. 2.
    Chou J (1991) Quantitation of synergism and antagonism of two or more drugs by computerized analysis. In: Chou T-C, Rideout DC (eds) Synergism and antagonism in chemotherapy. Academic Press, New York, pp 223–244Google Scholar
  3. 3.
    Chou J, Chou T-C (1987) Dose-effect analysis with microcomputers: quantitation of ED50, LD50, synergism antagonism, low-dose risk, receptor-ligand binding and enzyme kinetics. Manual and software, Biosoft, Cambridge, EnglandGoogle Scholar
  4. 4.
    Chou T-C (1976) Derivation and properties of Michaelis-Menten type and Hill type equations for reference ligands. J Theor Biol 39: 253–276Google Scholar
  5. 5.
    Chou T-C (1991) The median-effect principle and the combination index for quantitation of synergism and antagonism. In: Chou T-C, Rideout D (eds) Synergism and antagonism in chemotherapy. Academic Press, New York, pp 61–102Google Scholar
  6. 6.
    Chou T-C, Talalay P (1981) Generalized equations for the analysis of inhibitors of Michaelis-Menten and higher order kinetic systems with two or more mutually exclusive and nonexclusive inhibitors. Eur J Biochem 115:207–216Google Scholar
  7. 7.
    Chou T-C, Talalay P (1984) Quantitative analysis of dose-effect relationships: the combined effects of multiple drugs or enzyme inhibitors. Adv Enzyme Regul 22:27–55Google Scholar
  8. 8.
    Chou T-C, Talalay P (1987) Applications of the median-effects principle for the assessment of low-dose risk of carcinogens and for the quantitation of synergism and antagonism of chemotherapeutic agents. In: Harrap KR, Connors TA (eds) New avenues in developmental cancer chemotherapy. (Bristol-Myers Symposium series) Academic Press, New York, pp 37–64Google Scholar
  9. 9.
    Eastman A (1986) Reevaluation of interaction ofcis-dichloro(ethylennediammine)platinum(II) with DNA. Biochemistry 25: 3912–3915Google Scholar
  10. 10.
    Kris MG, Kinahan JJ, Gralla RJ, Fanucchi MP, Weitheim MS, O'Connell JP, Marks LD, Williams L, Farag F, Young CW, Sirotnak FM (1988) Phase I trial and clinical pharmacological evaluation of 10-ethyl-10-deazaminopterin in adult patients with advanced cancer. Cancer Res 48:5573–5579Google Scholar
  11. 11.
    Rozeneweig M, Hoff DD von, Abele R, Muggia FM (1980) Cisplatin. In: Pinedo HM (ed), EORTC cancer chemotherapy annual 2. Excerpta Medica, Amsterdam, pp 107–117Google Scholar
  12. 12.
    Schmid FA, Sirotnak FM, Otter GM, et al (1985) New folate analogs of the 10-deazaaminopterin series: markedly increased antitumor activity of the 10-ethyl analog compared to the parent compound and methotrexate against some human tumor xenografts in nude mice. Cancer Treat Rep 69:551–553Google Scholar
  13. 13.
    Schmid FA, Sirotnak FM, Otter GM, DeGraw JI (1987) Combination chemotherapy with a new folate analog: activity of 10-ethyl-10-deazaminopterin compared to methotrexate with 5-fluorouracil and alkylating agents against advanced metastatic disease in murine tumor models. Cancer Treat Rep 71:727–732Google Scholar
  14. 14.
    Shum KY, Kris MG, Gralla RJ, Marks LD, Heeland RT (1988) Phase II study of 10-ethyl-10-deaza-aminopterin in patients with stage III and IV nonsmall cell lung cancer. J Clin Oncol 6: 446–450Google Scholar
  15. 15.
    Sirotnak FM, DeGraw JI, Schmid FA, et al (1984) New folate analogs of the 10-deaza-aminopterin series. Further evidence for markedly increased antitumor efficacy compared with methotrexate in ascitic and solid murine tumor models. Cancer Chemother Pharmacol 12:26–30Google Scholar
  16. 16.
    Sirotnak FM, Schmid FA, Samuels LL, DeGraw JI (1987) 10-Ethyl-10-deaza-aminopterin: structural design and biochemical, pharmacologic, and antitumor properties of folates and folic acid antagonists in cancer chemotherapy. NCI Monogr 5:127–131Google Scholar
  17. 17.
    Webb JL (1963) Effect of more than one inhibitor. In: Webb JL (ed) Enzyme and metabolic inhibitors, vol 1. Academic Press, New York, pp 66–79, 488–512Google Scholar
  18. 18.
    Zwelling LA, Michaels S, Schwartz H, Dobson OPP, Kohn KW (1981) DNA cross-linking as an indicator of sensitivity and resistance of mouse L1210 leukemia cells tocis-diamminedichloroplatinum(II) andl-phenylalanine mustard. Cancer Res 41:640–649Google Scholar

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • Ting-Chao Chou
    • 1
  • Queng-Hui Tan
    • 1
  • Francis M. Sirotnak
    • 2
  1. 1.Laboratory of Biochemical PharmacologyMemorial Sloan-Kettering Cancer CenterNew YorkUSA
  2. 2.Laboratory of Molecular TherapeuticsMemorial Sloan-Kettering Cancer CenterNew YorkUSA

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