Figure 5. Knocking down TOPK attenuates the inhibitory effect of colon cancer cell growth by pantoprazole.

A. Expression level of TOPK in HCT116 cells is decreased by knockdown of TOPK. HCT116 cells were transiently transfected with shMOCK or shTOPK (#1-#5) and cell lysates were analyzed by western blot. B. TOPK has less effect on anchorage-independent cell growth of shTOPK transfected cells than that of shMOCK cells. HCT116 cells were grown in soft agar with pantoprazole (100 μM) for 10 days and the colonies were counted. Data are represented as mean ± standard deviation from triplicate experiments. The asterisks (**) indicate a significant decrease compared with shMOCK cells (P < 0.01). C. Pantoprazole inhibits TOPK activity in HCT 116 cells. After HCT116 cells (2 × 10⁶) were cultured in a 10-cm dish for 24h, the cells were starved in serum-free medium for another 24h, in the meantime the cells were treated with pantoprazole (100 μM) for (0-12 h), then treated with EGF (80 ng/ml) for 15 min. The cells were then harvested and the protein levels were determined by western blot analysis using specific antibodies. Data are representatives of results from triplicate experiments.