Figure 4. Danshensu enhances IR-induced apoptosis and the radiosensitivity of NSCLC cells.

(a,b) The mRNA and protein expressions of three NF-κB-regulated prosurvival genes (BIRC2, BIRC3, and BIRC5) were significantly upregulated after IR, but these upregulations were blocked by danshensu, selegiline or MAOB siRNA. *p < 0.05 vs. non-irradiated cells; **p < 0.05 vs. irradiated cells. (c) Apoptotic cell death was assessed using a DNA fragmentation assay. When IR-induced MAOB and NF-κB activation were inhibited NSCLC cell viability was adversely affected. *p < 0.05 vs. non-irradiated cells; **p < 0.05 vs. irradiated cells. (d) The colony formation assay showed that NF-κB activation by IR or the inhibition of MAOB by 50 μM danshensu, 2 μM selegiline, and 20 μM PDTC suppressed long-term cell proliferation.