Progesterone augments epirubicin-induced apoptosis in HA22T/VGH cells by increasing oxidative stress and upregulating Fas/FasL

Background: Although epirubicin, an anthracycline drug, is widely used to treat hepatocellular carcinoma, its therapeutic efficacy is disappointing. Thus, the efficacy of epirubicin may be improved when combined with other drugs. This study investigated the therapeutic potential of combination of progesterone and epirubicin in the treatment of the human hepatoma cell line HA22T/VGH and the possible mechanisms through which this combination might induce apoptosis. Materials and methods: HA22T/VGH cells were treated without or with 25 mu M progesterone and/or 0.5 mu M epirubicin and analyzed for oxidative stress, redox status, Fas/FasL expression, caspase activity, and apoptosis. Results: HA22T/VGH cells treated with epirubicin increased the production of reactive oxygen species and nitric oxide, the expression of Fas, FasL, and Fas-associated death domain, and the activities of caspase-8 and caspase-3. Epirubicin treatment also decreased glutathione resulting in the induction of apoptosis. Treatment with progesterone alone increased nitric oxide production, but it did not affect the other parameters. However, when HA22T/VGH cells were treated with progesterone and epirubicin, the effects of epirubicin were enhanced. Conclusions: Our observations suggest that progesterone enhances the efficacy of epirubicin. The increased efficacy is potentially attributed to progesterone's enhancement of epirubicin-induced oxidative stress, thereby reducing redox status. In addition, progesterone sequentially upregulates Fas/FasL to induce the caspase-8 and caspase-3 pathways, thereby resulting in increased apoptosis. The combination had a greater effect on the induction of HA22T/VGH cell apoptosis and could potentially serve as a more effective treatment for hepatocellular carcinoma than epirubicin alone. (C) 2014 Elsevier Inc. All rights reserved.