Skip to main content
. 2014 Dec 23;9(12):e115600. doi: 10.1371/journal.pone.0115600

Figure 3. CDDO-Me is a potent radiation countermeasure in bronchial and breast epithelial cells, and Nrf2 knockdown abrogates these radioprotective effects.

Figure 3

(A) Normal breast and lung epithelia are radioprotected at multiple doses of CDDO-Me. Cells were treated with drug 18 hours before exposure to 3 Gy gamma IR, then seeded immediately into clonogenicity. Colonies grown for ∼14 days before fixation with 6% glutaraldehyde/0.5% crystal violet stain. Mean ± SEM of four experiments seeded in triplicate, *p<0.05, **p<0.001 using t-test (compared to DMSO at 3 Gy). (B, C) HMEC and (D) HBEC cells pre-treated with 10 nM CDDO-Me have a significant increase in clonogenic survival. (E) HBEC 3KT with sh-Nrf2 see no radioprotection when pre-treated with CDDO-Me. Clonogenic survivals, mean ± SEM with linear-quadratic fit curve of four experiments seeded in triplicate. (F) Nrf2 knockdown cells have a ∼90% decrease of Nrf2 activity compared to non-silencing control, with diminished basal and CDDO-Me-induced ARE-luciferase activity. Mean ± SEM of six replicates, *p<0.05, **p<0.01, t-test (compared to non-silencing control).