Aromadendrene oxide 2, induces apoptosis in skin epidermoid cancer cells through ROS mediated mitochondrial pathway

Aromadendrene oxide 2 (AO-(2)) is an oxygenated sesquiterpene naturally found as a chemical component of essential oils. In the present study anticancer activity of AO-(2) has been investigated on A431 human epidermoid cancer and precancerous HaCaT cells.

Cell viability was used to detect cytotoxic activity. Mechanism of cell death induced by AO-(2) treatments was studied using Annexin V-FITC/PI binding, cell cycle analysis, measurement of MMP and ROS generation by flow cytometry. Expression of apoptosis related proteins was investigated by western blot.

AO-(2) inhibited the growth and colony formation ability of A431 and HaCaT cells in concentration dependent manner. It induced cell cycle arrest at G0/G1 phase and apoptosis through intracellular ROS accumulation. Inhibition of intracellular ROS by ascorbic acid and N-acetyl cysteine treatment completely blocked apoptotic effect. N-acetyl cysteine treatment significantly reversed G0/G1 arrest induced by AO-(2). AO-(2) treatment caused loss of mitochondrial membrane potential (ΔΨm), increase in Bax/Bcl-2 ratios, cytochrome c release, activation of caspases (cleaved caspase-3 and caspase-9) and PARP cleavage. AO-(2) also significantly inhibited the growth of multicellular tumor spheroids of A431 and HaCaT cells.

The results of the present study reveals that AO-(2) a chemical component of essential oils induces apoptosis in A431 and HaCaT cells.