Melanomas display increased cytoprotection to hypericin-mediated cytotoxicity through the induction of autophagy.

Abstract

Photodynamic therapy (PDT) as a regime for melanoma is of limited success due to factors such as the efficacy of the photosensitizer used, penetration depth and the presence of pigment. We characterised a pigmented and an unpigmented melanoma cell line with respect to their phenotypes. Cell viability was assessed after exposure to hypericin, a UVA-activated photosensitizer. Exposure to 3 microM activated hypericin induced a cytoprotective (autophagic) response from both cell lines. However, the pigmented cells accumulated a large amount of glycogen in their cytoplasm. We hypothesise that the treatment induces an initial cytoprotective response through autophagy, but with increased stress results in a different mode of cell death in pigmented melanoma cells from unpigmented cells. These results indicate that hypericin-PDT could be an adjuvant therapy for melanoma.

• Authors: Lester M Davids, Britta Kleemann, Susan Cooper, Susan H Kidson
• Journal: Cell biology international (Cell Biol Int) Vol. 33 Issue 10 Pg. 1065-72 (Oct 2009) ISSN: 1095-8355 [Electronic] England
• PMID: 19596456 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anthracenes
• Melanins
• Radiation-Sensitizing Agents
• Perylene
• hypericin
• Monophenol Monooxygenase

Topics

• Anthracenes
• Autophagy (drug effects, physiology)
• Cell Death (drug effects, physiology)
• Cell Line, Tumor
• Cell Survival (drug effects, physiology)
• Drug Resistance, Neoplasm
• Humans
• Melanins (analysis)
• Melanoma (drug therapy, metabolism, ultrastructure)
• Monophenol Monooxygenase (metabolism)
• Perylene (analogs & derivatives, metabolism, pharmacology, therapeutic use)
• Photochemotherapy
• Radiation Tolerance
• Radiation-Sensitizing Agents (metabolism, pharmacology, therapeutic use)
• Skin Neoplasms (drug therapy, metabolism, ultrastructure)
• Ultraviolet Rays