Figure 7.

Tryptophan metabolism by IDO1 positively regulates self-renewal of cervical CSCs. (A) SiHa cells were transduced with lentiviruses carrying IDO1 specific shRNAs (IDO1#1 or IDO1#2) or control LacZ specific shRNA (LacZ) followed by selection with puromycin. The surviving cells were collected at 48 h and 2 × 10³ cells were used to perform primary tumorsphere cultivation and the tumorsphere numbers were counted at day 7, followed by collecting formed primary tumorspheres with 100 μm cell strainer. The collected primary tumorspheres were dissociated into single cells and 1 × 10³ cells were used for secondary tumorsphere formation followed by counting the tumorsphere number at day 7. * p < 0.05; ** p < 0.01 when compared to sh-LacZ group. (B,C) HeLa and SiHa cells were performed tumorsphere cultivation in the supplement of 100 μM kynurenine. The tumorsphere numbers were counted at day 7. The total RNA was collected at 48 h after kynurenine treatment and the expression of BMI1, Oct4 or Sox2 were determined by qRT-PCR method. * p < 0.05; ** p < 0.01. All the experiments were repeated three times and data from one experiment were presented.