*Article* **Combination Therapy of Curcumin and Disulfiram Synergistically Inhibits the Growth of B16-F10 Melanoma Cells by Inducing Oxidative Stress**

**Sheila S. Fontes 1, Mateus L. Nogueira 1, Rosane B. Dias 1,2, Clarissa A. Gurgel Rocha 1,2, Milena B. P. Soares 1,3, Marcos A. Vannier-Santos 4,\* and Daniel P. Bezerra 1,\***


**Abstract:** Oxidative stress plays a central role in the pathophysiology of melanoma. Curcumin (CUR) is a polyphenolic phytochemical that stimulates reactive oxygen species (ROS) production, while disulfiram (DSS) is a US FDA-approved drug for the treatment of alcoholism that can act by inhibiting the intracellular antioxidant system. Therefore, we hypothesized that they act synergistically against melanoma cells. Herein, we aimed to study the antitumor potential of the combination of CUR with DSS in B16-F10 melanoma cells using in vitro and in vivo models. The cytotoxic effects of different combination ratios of CUR and DSS were evaluated using the Alamar Blue method, allowing the production of isobolograms. Apoptosis detection, DNA fragmentation, cell cycle distribution, and mitochondrial superoxide levels were quantified by flow cytometry. Tumor development in vivo was evaluated using C57BL/6 mice bearing B16-F10 cells. The combinations ratios of 1:2, 1:3, and 2:3 showed synergic effects. B16-F10 cells treated with these combinations showed improved apoptotic cell death and DNA fragmentation. Enhanced mitochondrial superoxide levels were observed at combination ratios of 1:2 and 1:3, indicating increased oxidative stress. In vivo tumor growth inhibition for CUR (20 mg/kg), DSS (60 mg/kg), and their combination were 17.0%, 19.8%, and 28.8%, respectively. This study provided data on the potential cytotoxic activity of the combination of CUR with DSS and may provide a useful tool for the development of a therapeutic combination against melanoma.

**Keywords:** curcumin; disulfiram; melanoma; apoptosis; oxidative stress
