Fig. 6

Dexamethasone (DEX) induces circadian rhythms and reduces HCT-116 cell proliferation and tumor growth in vivo. a, b Per2 and Nr1d1 gene expression in cultured HCT-116 cells 24–44 h after DEX treatment. Significant rhythms are illustrated with fitted cosine curves, otherwise data are connected by straight lines between data points, indicating no significant circadian rhythms (n = 17–18, 3–4 wells/time point, cosine-wave regression, F-test: DEX: p < 0.05, control: p > 0.05). c, d Cell numbers (c) and apoptotic cells stained with Annexin V (d) 24–72 h after DEX or control treatment (n = 5–6 wells/time point). Two-way ANOVA, posthoc test, *p < 0.05, ****p < 0.0001. e Volume of HCT-116 subcutaneous tumors in NSG mice injected intra-tumorally at day 0, 2, 4, 6, 8, 10 and 12 with DEX or phosphate-buffered saline (PBS) (n = 5 mice/group/time point, two-way ANOVA, p < 0.0001). Data are represented as mean ± standard error of the mean. For details of statistics, see Additional file 1