Extended Data Fig. 5: Dietary methionine restriction promotes intestinal cancer progression and suppresses anti-tumor immunity through gut microbiota in immunocompetent mice.
a, Schematic of the fecal transplantation experiment. C57BL/6J mice were fed with either CTRL diet or a MR diet for 2 weeks. Fresh fecal solutions from these fed mice were then gavaged into antibiotic treated Apcmin+/− mice daily for one week. The recipient Apcmin+/− mice were fed with regular chow diet for the duration of the experiment, and intestinal tumors were analyzed 2-3 weeks after fecal transplantation. Mouse cartoon images were drawn by using pictures from Servier Medical Art (https://smart.servier.com/wp-content/uploads/2016/10/Animals.pptx). Servier Medical Art by Servier is licensed under a Creative Commons Attribution 3.0 Unported License (https://creativecommons.org/licenses/by/3.0/). b-c, Relative fecal abundance of total 16S rRNA gene and A. muciniphila in recipient Apcmin+/− mice during antibiotic depletion of gut microbiota and fecal transplantation. The recipient Apcmin+/− mice were treated with antibiotics (Abx) and fecal transplanted (FT) as described in Methods. Their feces were collected at indicated days to confirm the success of gut bacteria depletion and fecal transplantation by qPCR (n = 5 FT-CTRL and 7 FT-MR). d, Apcmin+/− mice transplanted with feces from MR diet fed C57BL/6J mice have reduced abundance of CD3+ T cells in the blood and small intestine. Representative flow cytometry plots are shown. e, Apcmin+/− mice transplanted with feces from MR diet-fed C57BL/6J mice have more intestinal tumors. Representative tumor images are shown. f, Fecal bacteria levels in regular and GF mice after CTRL or MR diet feeding (n = 4, 5, 4, and 4 mice/group, 2-way ANOVA). g–h, MR fails to significantly alters tumor growth and circulating T cell abundance in germ-free Balb/c mice. Germ-free Balb/c mice fed with irradiated CTRL or MR diets were subcutaneously injected with CT26.CL25 cells as described in Methods (n = 4 mice/8 tumor injections/group, two-tailed unpaired Student’s t-test). i, MR reduces body weight of germ-free Balb/c mice (n = 4 mice/group, two-tailed unpaired Student’s t-test). Values in are expressed as mean ± s.e.m. Details of statistical tests are included in the Methods.
