Cytotoxic and apoptotic effects of caffeate derivatives on A549 human lung carcinoma cells

Background: Caffeate derivatives have been reported to exhibit antioxidant, anti-inflammatory, and anticancer activities. To reveal the cytotoxic and apoptotic effects of caffeate derivatives, we studied the effects of octyl, phenylpropyl, and decyl caffeates on cell growth and apoptosis in A549 human lung carcinoma cells. Methods: A549 human lung carcinoma cells were treated with 0-100μM of caffeate derivatives for 0-48 hours. The cytotoxic and apoptotic effects were evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay for cell viability, propidium iodide staining method for cell morphology, mitochondrial membrane potential analysis, and Western blot for protein expression. Results: Octyl, phenylpropyl, and decyl caffeates all significantly decreased the cell viability of A549 cells with 50% inhibitory concentration values of 54.2±10.1μM, 80.2±1.3μM, and 74.9±2.1μM, respectively. Propidium iodide staining revealed that apoptotic bodies appeared when cells were treated with octyl and decyl caffeates. Treatment of A549 cells with octyl and decyl caffeates caused the loss of mitochondria membrane potential. Western blots revealed that octyl and decyl caffeates stimulate an increase in the protein levels of Fas, FasL, and Apaf-1. Moreover, these compounds changed the levels of pro- and antiapoptotic Bcl-2 family members and induced the activation of caspase-12, -9, and -3, which was followed by cleavage of poly (ADP-ribose) polymerase. Conclusion: These results demonstrate that octyl and decyl caffeates induce cell apoptosis in A549 human lung carcinoma cells.