Differential mechanistic investigation of protective effects from imperatorin and sec-O-glucosylhamaudol against arsenic trioxide-induced cytotoxicity in vitro.

BACKGROUND AND PURPOSE

The clinical use of arsenic trioxide (AsO) for treating acute promyelocytic leukemia (APL) is limited due to its severe cardiotoxicity. The possible mechanisms of AsO-induced cardiotoxicity include DNA fragmentation, reactive oxygen species (ROS) generation, cardiac ion channel changes and apoptosis. The present study is designed to investigate the protective effects of imperatorin and sec-O-glucosylhamaudol and to explore their mechanistic involvement in AsO-induced cytotoxicity.

EXPERIMENTAL METHODS

Cell viability assay, Lactate dehydrogenase (LDH) release, Acridine orange/ethidium bromide (AO/EB) double staining, Caspase-3 activity assay, ROS generation, cellular calcium levels, mRNA expression levels by qRT-PCR and protein expression levels by Western blotting were measured in H9c2 cells in combination with AsO and imperatorin or sec-O-glucosylhamaudol.

KEY RESULTS

We observed that H9c2 cells treated with imperatorin or sec-O-glucosylhamaudol were more resistant to AsO-induced cell death. Both imperatorin and sec-O-glucosylhamaudol reduced H9c2 cell apoptosis, but both imperatorin and sec-O-glucosylhamaudol had no effects on Caspase-3 activity and intracellular calcium accumulation. Furthermore, imperatorin was capable of suppressing ROS generation, while sec-O-glucosylhamaudol did not show this effect. Moreover, imperatorin and sec-O-glucosylhamaudol triggered Nrf2 activation, which resulted in upregulation of downstream phase II metabolic enzymes and antioxidant protein/enzyme, probably offering cellular protection to AsO-induced cardiotoxicity via the Nrf2 signal pathway.

CONCLUSIONS AND IMPLICATIONS

Imperatorin and sec-O-glucosylhamaudol can ameliorate AsO-induced cytotoxicity and apoptosis in H9c2 cells, the mechanisms probably related to antioxidation. AsO in combination with imperatorin or sec-O-glucosylhamaudol could be considered as a novel strategy to expand the clinical application of AsO.