Fig. 5: Methionine restriction reduces faecal hydrogen sulfide production and suppresses antitumour immunity in immunocompetent Apcmin+/− mice.
a, MR reduced faecal H2S production activity. Faeces from CTRL or MR diet-fed C57BL/6J donor mice as well as respective Apcmin+/− recipient mice were subjected to H2S production assay using the lead sulfide assay as described in Methods (n = 6 mice each for C57BL/6J donor groups; 9 mice each for Apcmin+/− recipient groups, two-tailed unpaired Student’s t-test). b, Oral supplementation of GYY4137 rescues MR-induced increase of tumour progression in Apcmin+/− mice. Apcmin+/− mice transplanted with faeces from CTRL- or MR-fed B6 mice were oral gavaged daily with vehicle (V) or GYY4137 (GYY) as described in Methods (n = 8 mice on CTRL diet, 6 mice on MR diet and 9 mice on MR diet + GYY, Kruskal–Wallis test). c, Oral supplementation of GYY4137 rescued MR-induced reduction of Ifng, Gzma and Gzmb mRNA in the tumour-containing intestine of Apcmin+/− mice. Apcmin+/− mice were treated as in b, and the mRNA levels of indicated genes were analysed by qPCR (n = 9 mice per group, Kruskal–Wallis test). d, Oral supplementation of GYY4137 rescued the survival of Apcmin+/− mice on MR diet. Apcmin+/− mice were treated as in b (n = 16 mice on CTRL diet, 11 mice on MR diet and 9 mice on MR diet + GYY, log-rank test). Values are expressed as the mean ± s.e.m., except in d. Details of statistical tests are in Methods. NS, not significant.
