Melanogenesis and DNA damage following photodynamic therapy in melanoma with two meso-substituted porphyrins.
Melanoma, a cancer derived from melanocytes is very difficult to treat, especially in advanced cases. There are several encouraging studies of the efficacy of photodynamic therapy (PDT) in melanoma. However, PDT has to overcome the main defense mechanisms like: defects in the apoptotic pathways, pigmentation, sequestration of the photosensitisers (PS) inside melanosomes and increased oxidative stress defense. Two meso-substituted porphyrins, meso-5,10,15,20-tetrakis (4-hydroxyphenyl) porphyrin (THOPP) and meso-5-(4-hydroxyphenyl)-10, 15, 20-tris (4-methoxyphenyl) porphyrin (THOMPP) were used as PS to investigate several mechanisms underlining the PDT anti-melanoma effects, on a lightly pigmented melanoma cell line (WM35), in vitro. γH2AX foci formation (a measure of DNA double strand brakes) was used for the assessment of DNA damage by means of immune-fluorescence and western blot. Cytoskeleton alterations were detected by phalloidin staining. Tyrosinase activity and melanin pigment were quantified by spectrophotometry, tyrosinase protein by western blot, total peroxidase activity by resorurfin reaction (Amplex Red). PDT induced high levels of DNA damage, cytoskeleton alterations and enhanced pigmentogenesis. THOPP mediated PDT was the most efficient. The melanogenesis stimulated by PDT was directly correlated to the PDT induced cellular damage and provided no protection against therapy. Thus, PDT induced melanogenesis combined with severe DNA damage was able to overcome the mechanisms of resistance and increased the efficiency of PDT in WM35 melanoma cells. These results are encouraging for a possible use of PDT, as an adjuvant therapy in lightly pigmented melanomas.
University of Medicine and Pharmacy, Department of Physiology, Clinicilor 1, Cluj-Napoca, Romania. Electronic address: baldeai@yahoo.com.
Ioana
I
Baldea
University of Medicine and Pharmacy, Department of Physiology, Clinicilor 1, Cluj-Napoca, Romania. Electronic address: ariana_di@yahoo.com.
Diana Elena
DE
Olteanu
University of Agricultural Sciences and Veterinary Medicine, Department of Pathology, Calea Manastur 3-5, 400372 Cluj-Napoca, Romania; Ross University School of Veterinary Medicine, Department of Biomedical Sciences, PO Box 334, Basseterre, St. Kitts, West Indies. Electronic address: pbolfa@rossvet.edu.kn.
Pompei
P
Bolfa
University of Agricultural Sciences and Veterinary Medicine, Department of Pathology, Calea Manastur 3-5, 400372 Cluj-Napoca, Romania. Electronic address: flaviu_tabaran@yahoo.com.
Flaviu
F
Tabaran
National Institute for Research & Development in Chemistry and Petrochemistry-ICECHIM, Nanomedicine Research Group, 202 Splaiul Independentei, Sector 6, Bucharest, Romania. Electronic address: rodicaion2000@yahoo.co.uk.
Rodica-Mariana
RM
Ion
University of Medicine and Pharmacy, Department of Physiology, Clinicilor 1, Cluj-Napoca, Romania. Electronic address: adrianafilip33@yahoo.com.
Gabriela Adriana
GA
Filip
D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D045744:Cell Line, Tumor; D003599:Cytoskeleton / Q000473:pathology; D004249:DNA Damage / Q000187:drug effects* / Q000528:radiation effects; D006801:Humans; D008027:Light; D008543:Melanins / Q000378:metabolism*; D008545:Melanoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D018613:Microscopy, Confocal; D014442:Monophenol Monooxygenase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry / Q000627:therapeutic use / Q000633:toxicity*; D011166:Porphyrins / Q000737:chemistry / Q000627:therapeutic use / Q000633:toxicity*
C000615594:5-(4-hydroxyphenyl)-10,15,20-tris(4-methoxyphenyl)porphyrin; D008543:Melanins; D017319:Photosensitizing Agents; D011166:Porphyrins; C051232:5,10,15,20-tetra(4-hydroxyphenyl)porphyrin; D010544:Peroxidases; D014442:Monophenol Monooxygenase
Melanogenesis; Melanoma; Meso-substituted porphyrins; Photodynamic therapy; γH2AX