Figure 7. PON1 supports escape from drug- and ligand-induced cell death in lung cancer cells.

(A) Cell growth inhibition rate after binary dose-dependent treatment with chemotherapeutics. (B, C) FACS-based detection of drug-induced apoptotic fraction (sub-G₁ phase) of cells and identification of early and late apoptosis. Symbols represent mean ± S.E.M. (D) Upon induction of apoptosis by various indicated chemotherapeutic drug (0.8 μM STS, 60 μM 5-FU, 60 μM PTX, 60 μM CIS, 10 μM ETOP) for 16 h, cells were assessed for nuclear morphology by DAPI staining shown as representative fluorescent images. (E) The same cells and drug treatment procedures were used in TUNEL assay as in D. Bar graph (right panel) shows representative total count of brightly stained nuclei of apoptotic cells. (F) Western blotting of cells to examine endogenous levels of total and phospho-p53, pro-caspases 3 and 8, p21, p27, total and phospho-ERK, and total and phospho-Akt. β-actin served as the loading control. (G) Cells were either treated with 0.01% DMSO or 1 μM STS and analyzed for Annexin-V-FITC/PI by FACS. (H) Cells were treated with either 0.01% DMSO or 5 μM STS for 48 h and assessed for intracellular ATP levels. (I, J) Cells were treated with 200 U TNF-α, 30 ng/μL TRAIL, 1 μM STS for 16 h, individually or both in combination with STS, and assayed for caspase-3/7 activation. (K) Cells were loaded with either 20 μM ETOP or 2 μM STS for 8 h and subjected to protein blotting with antibodies against total and phospho-p53, cleaved caspases 3 and 8, p27, and p21. β-Actin served as the loading control. Images and figures were selected as representative data from three independent experiments. Three independent experiments were summarized. Symbols represent mean ± S.E.M. n = 3~7; n.s., not significant; *P<0.05; **P>0.01.