Fig. 11

AHR down-regulation decreases expression of Ahr, Aldh1a1, Cyp1b1, and Sox2 in xenografted mouse tumors. Twenty NOD/SCID mice were injected with 3,000 dox-inducible shAhr-transduced ALDH^high or ALDH^low SUM149 cells as described in Fig. 10. Half of the mice were provided with water containing 2 mg/mL doxycycline to induce the shAhr and tumors were harvested after 42–72 days when they reached 15 mm in total size (control mice n = 20, mice with doxycycline treatment n = 19). (a) Ahr, (b) Cyp1b1, (c) Aldh1a1, and (d) Sox2 mRNA expression levels were assayed by RT-qPCR. Since the AHR controls expression of Cyp1b1, Aldh1a1, and Sox2 in both ALDH^high and ALDH^low cells (e.g. Fig. 3), data generated with tumors from ALDH^high and ALDH^low tumors were pooled for statistical purposes. Data are presented as fold-change relative to the average CT value from control mice, i.e. no dox, grafted with ALDH^low cells ± standard error. Asterisks indicate a significant decrease in the mRNA fold-change, *P <0.05, **P <0.01, ***P <0.005