Table 1

In vitro and in vivo antitumoral effects of Met-free medium or Met-free diets with and without ethionine (Eth)

TreatmentSNB19TC71-MASCLC6SCLC6-Dox
MetHcy+MetHcy+ + EthaMetHcy+MetHcy+ + EthMetHcy+MetHcy+ + EthMetHcy+ + Eth
Cell proliferation index
(% of control)b63c ± 516d ± 217d ± 0.12d ± 0.152c ± 450c ± 7NDe
Tumor growth inhibition (Mean %± SD)26f ± 453c ± 846c ± 1356c ± 1012f ± 1028c ± 164f ± 2
Tumor doubling time in days (control)6 (5)8 (5)13 (11)26 (11)5 (4)6 (4)4 (4)
Tumor growth delay in days26413651121311
Survival prolongation ratiog11.61.52.111.11
  • a Ethionine was injected i.p. daily, at a dose of 200 mg/kg. Mice were fed a MetHcy+ diet as soon as the tumors reached a 60–100 mm3.

  • b Percentage of surviving cell number after a 3-day culture in Met-free, Hcy-supplemented medium, with or without ethionine (0.5 mg/ml), as compared to the number of cells cultured in Met-containing medium.

  • c 0.05 < P < 0.01.

  • d P < 0.01.

  • e ND, not determined.

  • f P > 0.05, statistically nonsignificant.

  • g Ratio to the survival time of untreated mice.