Photochemoprevention of UVB‐induced skin carcinogenesis in SKH‐1 mice by brown algae polyphenols

• Published in: International journal of cancer 2006-12, Vol.119 (12), p.2742-2749
• Main Authors: Hwang, Hyejeong, Chen, Tong, Nines, Ronald G., Shin, Hyeon‐Cheol, Stoner, Gary D.
• Format: Article
• Language: English
• Subjects: Administration, Cutaneous; Administration, Oral; Animals; antioxidant; Benzofurans - administration & dosage; Benzofurans - chemistry; Benzofurans - pharmacology; Biological and medical sciences; Blotting, Western; brown algae polyphenols; Carcinogenesis, carcinogens and anticarcinogens; Cell Proliferation - drug effects; Cell Proliferation - radiation effects; Chemical agents; chemoprevention; Cyclooxygenase 2 - genetics; Cyclooxygenase 2 - metabolism; Dinoprostone - metabolism; Dioxins - administration & dosage; Dioxins - chemistry; Dioxins - pharmacology; Epidermis - drug effects; Epidermis - metabolism; Epidermis - radiation effects; Female; Flavonoids - administration & dosage; Flavonoids - chemistry; Flavonoids - pharmacology; Gene Expression - drug effects; Gene Expression - radiation effects; Immunohistochemistry; inflammation; Medical sciences; Mice; Molecular Structure; Neoplasms, Radiation-Induced - genetics; Neoplasms, Radiation-Induced - metabolism; Neoplasms, Radiation-Induced - prevention & control; Phaeophyceae - chemistry; Phenols - administration & dosage; Phenols - chemistry; Phenols - pharmacology; Polyphenols; Proliferating Cell Nuclear Antigen - analysis; Random Allocation; Reverse Transcriptase Polymerase Chain Reaction; Skin - drug effects; Skin - pathology; Skin - radiation effects; skin cancer; Skin Neoplasms - etiology; Skin Neoplasms - metabolism; Skin Neoplasms - prevention & control; Tumors; Ultraviolet Rays - adverse effects
• ISSN: 0020-7136; 1097-0215
• DOI: 10.1002/ijc.22147

Chronic exposure of the skin to ultraviolet B (UVB) radiation induces oxidative stress, which plays a crucial role in the induction of skin cancer. In this study, the effect of dietary feeding and topical application of brown algae polyphenols on UVB radiation‐induced skin carcinogenesis in SKH‐1 mice was investigated. SKH‐1 hairless mice were randomly divided into 9 groups, including control, UVB control and treatment groups. They were treated orally (0.1% and 0.5% with AIN‐76 diet, w/w) and topically (3 and 6 mg/0.2 ml of vehicle) with brown algae polyphenols and irradiated with UVB for 26 weeks. Dietary feeding (0.1% and 0.5%) of brown algae polyphenols significantly reduced tumor multiplicity (45% and 56%) and tumor volume (54% and 65%), and topical administration (3 and 6 mg) significantly decreased tumor multiplicity (60% and 46%) and tumor volume (66% and 57%), respectively, per tumor‐bearing mouse. Dietary feeding and topical administration of the polyphenols also inhibited tumor incidence by 6% and 21%, respectively, but the results were not significant. Dietary and topical administration of the polyphenols markedly inhibited cyclooxygenase‐2 activity and cell proliferation. These observations show that brown algae polyphenols have an antiphotocarcinogenic effect which may be associated with the prevention of UVB‐induced oxidative stress, inflammation, and cell proliferation in the skin. © 2006 Wiley‐Liss, Inc.