Figure 4.

Induction of ST1‐cell tumorigenicity by CA9. (a) ST1 cells were transfected with a wild‐type CA9 expression vector (CA9wt) or an empty vector (EV). CA9 expression on two transfected cell lines, ST1/CA9wt and ST1/EV, was verified by FACS. (b) ST1/CA9wt, ST1/EV, and ST1‐CA9^high cells were injected into six dorsal sites (1 × 10⁴ cells/site) in NOG mice and the number of palpable tumors that developed was monitored. (c) Tumor growth was observed weekly. Data are the mean with the SD of the tumor sizes at the six injection sites. *P < 0.05. (d) Vectors expressing CA9 shRNAs (shCA9‐1 or shCA9‐2) or an empty control vector (EV) were introduced into ST1‐CA9^high cells and CA9 expression was examined by FACS. (e) After introduction of shRNA, the cells were injected into six dorsal sites (1 × 10⁴ cells/site) of NOG mice and the number of palpable tumors that developed was monitored. (f) Tumor growth was assessed weekly. Data are the mean with the SD of the tumor sizes at the six injection sites. *P < 0.05.