Figure 2: Existence and manner of clonal expansion of Bmi1+ cells in developing small intestinal tumors and colon tumors.
(a,c,e) To assess the existence of Bmi1+ cells in developing tumor and the percentage of the tumors containing Bmi1+ cell-derived clone, FAP model (a), two-step caricinogenesis model (c), and sporadic carcinogenesis model (e) were set up using Bmi1CreERT/+; Rosa26rbw/+ mice. The percentage of the developing tumors that contained Bmi1+ positive cells was calculated by tamoxifen induction of tumor-bearing mice followed by 3-day chase and observation of the cells with rainbow color; mCerulean, mOrange, and mCherry (Day3). To evaluate the percentage of the tumors containing Bmi1+ cell-derived clone, tumor-bearing mice of three models were injected with tamoxifen and clones with rainbow color were examined at 7 days or 28 days after induction (a,c,e): Day7, and Day28. At the same time, tumors that contained rainbow-colored single cell, which was suggested to express Bmi1 when tamoxifen induction but had not divided, was categorized as “tumors containing Bmi1+ single cell”. The number of mice and tumors analyzed were shown in Supplementary Table 1. (b,d,f) The number of the cells that comprised each Bmi1+ cell-derived clone were measured, and the average is shown. Cell number per clone at day28 after tamoxifen induction was compared with day7. Error bars indicate standard deviation. **p < 0.01, *p < 0.05. The number of tumors analyzed and the raw data are shown in Supplementary Table 2.
