Figure 2.

Apoptosis-inducing effect of colicin N in human lung cancer cells (a) Reduction in cell viability detected by MTT assay of lung cancer H460 cells was observed after treatment with colicin N (1–15 µM) for 24 h. (b) Significantly concentration-dependent increase in apoptosis occurred after colicin N treatment. (c) Co-staining with Hoechst33342 and propidium iodide (PI) reveals blue fluorescence of apoptosis in H460 cells treated with 5–15 µM of colicin N for 24 h. Meanwhile, there was no noticeable necrosis presenting with red fluorescence. Values are means of the independent triplicate experiments ± SD. * p ≤ 0.05 versus non-treated control.