Cytotoxic Effect of p-Coumaric Acid on Neuroblastoma, N2a Cell via Generation of Reactive Oxygen Species Leading to Dysfunction of Mitochondria Inducing Apoptosis and Autophagy
p-Coumaric acid (p-CA), an ubiquitous plant phenolic acid, has been proven to render protection against pathological conditions. In the present study, p-CA was evaluated for its capacity to induce cytotoxic effect to neuroblastoma N2a cells and we report here the possible mechanism of its action. p-CA at a concentration of 150 μmol/L, upon exposure for 72 h, stimulated 81.23 % of cells to apoptosis, as evidenced by flow cytometer studies mediated through elevated levels of ROS (7.5-fold over control). Excess ROS production activated structural injury to mitochondrial membrane, observed as dissipation of its membrane potential and followed by the release of cytochrome c (8.73-fold). Enhanced generation of intracellular ROS correlated well with the decreased levels (~60 %) of intracellular GSH. Sensitizing neuroblastoma cells for induction of apoptosis by p-CA identified p53-mediated upregulated accumulation of caspase-8 messenger RNA (2.8-fold). Our data report on autophagy, representing an additional mechanism of p-CA to induce growth arrest, detected by immunoblotting and fluorescence, correlated with accumulation of elevated levels (1.2-fold) of the LC3-II protein and acridine orange-stained autophagosomes, both autophagy markers. The present study indicates p-CA was effective in production of ROS-dependent mitochondrial damage-induced cytotoxicity in N2a cells.
Keywordsp-Coumaric acid Neuroblastoma N2a cells Apoptosis p53 Caspase-8 Autophagy LC3-II
The authors acknowledge the recognition of the University of Mysore as an Institution of Excellence and financial support from the Ministry of Human Resource Development, Govt. of India through UGC under UOM/IOE/RESEARCH/1/2010-11, dt 22-04-2010 project.
Conflict of Interest
The authors declare that they have no conflict of interest.
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