Proceedings of Oncobiology Symposiums
Proceedings of XIV Oncobiology Symposium

INTRODUCTION AND OBJECTIVES: The incidence and number of deaths caused by melanoma has been increasing in recent years, and it is important to discover new drugs that act in different ways of progression and survival. In this sense, the C-phycocyanin (C-PC) pigment appears as a possible treatment, since it has shown antitumor action acting on different cellular targets. Thus, we evaluated through molecular docking the ability of C-PC to bind to the main cellular targets related to the progression of melanoma, and the reflection of this link in the biological effects in vitro in melanoma cells. MATERIAL AND METHODS: Protein-protein docking was performed with PRISM web server, and analyzed for the types of interactions and color using UCSF Chimera. For in vitro tests cell lines B16F10 (tumor) and melan-a (non-tumor) were used. The cells were treated with C-PC (100, 200 and 400 µg/mL), and the sensitivity were evaluated by Trypan Blue exclusion and Neutral Red assays 24, 48 and 72 h after exposure. From these tests the concentration of 400 µg/mL was chosen for further analysis in B16F10 cells. Apoptosis and necrosis were performed using acridine orange and ethidium bromide. Por analysis of the mitotic index the cells were fixed and stained with DAPI. The cell migration was analyzed by counting the cells that invaded the slit in the wells of the plate. RESULTS AND CONCLUSION: Molecular docking demonstrated that C-PC was able to bind to BRAF and MEK which are related to the signal transduction pathway in melanoma, acting in the regulation of pathways such as proliferation. Sensitivity tests confirmed the effect of C-PC on proliferation, since we observed a decrease in the number of viable cells at all concentrations tested 72 h after exposure, and in 48 and 72 h, we observed a mild cytotoxic effect for the concentration of 400 µg/mL. C-PC was unable to bind to the tetramerization domain of the protein involved with apoptosis p53, and despite binding to the anti-apoptotic protein Bcl2, our biological data showed that C-FC was unable to cause cell death. The effect of C-PC on proliferation was confirmed by the interaction of C-PC with the cyclin-dependent kinases CDK4 and CDK6. The in vitro assay demonstrated that C-PC was able to decrease the number of cells in mitosis. Molecular docking also demonstrated that C-PC interacted with proteins involved with migration and metastasis. We observed hydrogen bridge interactions with N-cadherin, in addition to C-PC interacting with matrix metalloproteinases MMP-2 and MMP-9. This link may be related to the effect of decreased cell migration observed in the in vitro assay. Finally, we demonstrated that C-PC did not affect the cell viability of the non-tumoral melan-a cells. We conclude that C-PC is a strong anti-tumor candidate for the treatment of melanoma, as it acts in different cellular pathways that confer aggressiveness and progression to melanoma, in addition to not causing damage to non-tumor cells.