Cell transfection of siRNA and plasmid

The STAT1-overexpressing plasmid was generated in this laboratory as described in our previous report. [17] STAT1-siRNAs were synthesized from GenePharma (Shanghai, China) and the sequences were listed in Supplementary Table 1. Briefly, after seeding in 6-well plates for 24 h, cells were transfected with 5 nM siRNA or 2.5 μg STAT1 plasmid for 6 h. After removing transfection reagents, cells were further incubated for 48 h. The transfected cells were lysed for mRNA and protein extraction or further used for sphere or colony formation assays.