Caffeic acid n-butyl ester-triggered necrosis-like cell death in lung cancer cell line A549 is prompted by ROS mediated alterations in mitochondrial membrane potential.

The aim of the present study was to evaluate the anticancer activity of caffeic acid n-butyl ester against lung cancer cell line A549 and to investigate the underlying mechanism.

IC50 was determined by MTT assay. Fluorescent probes DCFH-DA, Indo 1/AM, DiOC6 were used to determine ROS, Ca2+, and mitochondrial membrane potential (ΔΨm). ATP levels were determined by using ATP liteTM kit. DNA damage was investigated by DAPI and comet assays. Protein expression was investigated by Western blotting.

Caffeic acid n-butyl ester exhibited lowest IC50 of 25 µM against lung A549 cell line. Caffeic acid n-butyl ester reduced the cell viability of A549 cells concentration and time-dependently. It also augmented the discharge of ROS and Ca2+ and lessened the mitochondrial membrane potential (ΔΨm) and ATP levels in A549 cells. Additionally, caffeic acid n-butyl ester also prompted DNA damage in A549 cell line. Notably, caffeic acid n-butyl ester-stimulated the cytochrome c release only and exhibited no effect on the expression of apoptosis-related protein levels such as caspase-3, caspase-8, and Apaf-1.

Caffeic acid n-butyl ester exhibited significant anticancer activity against lung cancer cell line A549. However, the anticancer activity was not due to apoptosis as no significant change was observed in the expression of apoptosis-related proteins. The anticancer activity of caffeic acid n-butyl ester may be attributed to necrosis-like cell death prompted by ROS-mediated alterations in ΔΨm.

Taken together, we conclude that caffeic acid n-butyl ester-induced A549 cells death displayed a cellular pattern characteristic of necrotic cell death and not of apoptosis.