Theophylline enhances melanogenesis in B16F10 murine melanoma cells through the activation of the MEK 1/2, and Wnt/ß-catenin signaling pathways.

Theophylline is a kind of methyl xanthine, which has been suggested to inhibit the activity of phosphodiesterase and increase the intracellular level of cyclic adenine monophosphate (cAMP). Theophylline has also been reported to increase the length and complexity of the dendritic process in melanocytes. However, the mode of action of theophylline in melanogenesis has never been reported. In this study, the effects of theophylline on melanogenesis were evaluated spectrophotometrically by the mushroom tyrosinase activity assay and by the determination of the intracellular tyrosinase activity and melanin content. The expression levels of melanogenesis-related proteins were analyzed by Western blot. The results indicated that theophylline (100-500 µM) effectively enhanced melanogenesis in the B16F10 murine melanoma cells. Moreover, theophylline increased the protein expression levels of microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein 1 (TRP-1), and the level of phosphorylated extracellular regulated protein kinase (p-ERK) and phosphorylated glycogen synthase kinase-3ß (p-GSK3ß) were also increased. In summary, the results revealed that theophylline promoted melanogenesis in B16F10 cells by upregulating the mitogen-activated protein kinase kinase 1 (MEK 1/2) and Wnt/ß-catenin signaling pathways.

Anti-Cancer Effects of Sulfasalazine and Vitamin E Succinate in MDA-MB 231 Triple-Negative Breast Cancer Cells.

Aim: Sulfasalazine (SSZ) displayed anti-cancer activities. Vitamin E succinate (VES) could inhibit cell growth in various cancer cells. However, chemical therapies were often not useful for triple-negative breast cancer cells (TNBCs) treatment. Here, this study investigated the anti-cancer effects and the mechanisms on TNBCs under combination treatment with SSZ and VES. Methods: Cell viability was analyzed by using the MTT assay. The H2O2 levels were determined by using lucigenin-amplified chemiluminescence method. In addition, caspase and MAPs signals were studied by using western blotting. Results: Low-dose VES antagonized the SSZ-induced cytotoxicity effects while high-dose VES promoted the SSZ-induced cytotoxicity effects on TNBCs. In addition, SSZ alone treatment activated both caspase-3 and ERK signals, however, VES alone treatment only activated JNK signals. On the other hand, activation of caspase-3, JNK, and ERK were found in SSZ plus VES-treated cells. Conclusion: Combined SSZ and VES has synergistic or antagonistic cytotoxic effects depending on VES concentration. In addition, different cytotoxic signals are induced on SSZ-treated, VES-treated and SSZ plus VES-treated cells.