Mitophagy and mitochondrial morphology in human melanoma-derived cells post exposure to simulated sunlight

Abstract

Purpose: To assess changes in mitochondrial morphology and mitophagy induced by simulated sunlight irradiation (SSI) and how these changes are modulated by mitochondrial activity and energy source.

Materials and methods: Human malignant amelanotic melanoma A375 cells were pre-treated with either a mitochondrial activity enhancer, uncoupler or were either melanin or glutamine supplemented/starved for 4 hours pre-exposure to sunlight. A Q-Sun Solar Simulator (Q-Lab, Homestead, FL, USA) was employed to expose cells to simulated sunlight. Confocal microscopy imaging of A375 cells co-loaded with mitochondria and lysosome-specific fluorescent dyes was used to identify these organelles and predict mitophagic events.

Results: SSI induces pronounced changes in mitochondrial dynamics and mitophagy in exposed skin cells compared to control and these effects were modified by both glutamine and melanin.

Conclusions: Mitochondrial dynamics and rate of mitophagy in melanoma cells are sensitive to even short bursts of environmentally relevant SSI. Mitochondrial dynamics, and its modulation, may also play a role in mitophagy regulation, cell survival and proliferation post SSI.

Keywords:

• Mitochondrial dynamics
• mitophagy
• sunlight
• glutamine
• melanin
• melanoma

Acknowledgements

This work was supported by funding through the Science Foundation Ireland – Research Frontiers Program (SFI 06 RFP BIC006). We also thank Mr Rocky Bo Li and Ms Karina Carey for technical assistance.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.