Fig. 6: Bacteria affect the modulation of tamoxifen toxicity by apoptosis.

a Volcano plot distribution of genes whose expression changed significantly in animals fed E. coli and exposed to 400 µM tamoxifen (FDR <0.1, >2-fold change). A full list is provided in Supplementary Data 2. Pink indicates genes encoding enzymes participating in FA metabolism, and red indicates genes encoding enzymes that may be involved in the detoxification of tamoxifen. See also Supplementary Fig. 12. b–d DRCs of tamoxifen toxicity in animals fed E. coli expressing double-stranded RNA as indicated. Control indicates E. coli containing vector control plasmid (pL4440). Data are represented as mean ± SEM of three independent biological replicates. Statistical analysis of DRCs was conducted by performing two-way Anovas followed by a Dunnett multi-comparison test using the RNAi control condition, on GraphPad Prism (v9). Adjusted p values: <0.0001 (C. aquatica), 0.9949 (CYP-35B1), <0.0001 (CYP-35B3), and <0.0001 (R05D8.9). Notably, the significance of CYP35-B1 RNAi (c) rescue was not captured on the entire curve where no substantial toxicity can be overserved on the E. coli control, but rather on the highest drug-concentration where reliable toxicity can be observed (significance was tested using a two-sided paired t-test, p value: 0.0008). e–g DRCs of tamoxifen toxicity on apoptosis-deficient mutant animals fed E. coli (e), C. aquatica (f), or B. subtilis (g). Data were represented as mean ± SEM of three independent biological replicates. Statistical analysis of DRCs was conducted by performing two-way Anovas followed by a multi-comparison Dunnett test using the wild-type condition, on GraphPad Prism (v9). Adjusted p values: a 0.9517 (∆ced-4) and <0.0001 (∆ced-3), b 0.0032 (∆ced-4) and <0.0001 (∆ced-3), and c 0.3279 (∆ced-3) and 0.8866 (∆ced-4). h Kinetics of tamoxifen toxicity in ER-negative (MDA-MB-231) breast cancer cells in presence of the absence of FA cocktail, Ferrostatin-1 (ferroptosis inhibitor), Vitamin E, or ZVAD (apoptosis inhibitor). Data were represented as mean ± SD of four technical replicates. Representative results of one out of three independent experiments. See also Supplementary Fig. 13. Source data are provided as a Source Data file.