Inhibition of AP-1 and neoplastic transformation by fresh apple peel extract

Area of Science:

• Oncology
• Dermatology
• Biochemistry

Background:

• Fruit and vegetable consumption is linked to reduced cancer risk.
• Previous research indicates fresh apples may inhibit tumor cell proliferation.

Purpose of the Study:

• To investigate the chemopreventive effects of apple peel extract on skin carcinogenesis.
• To elucidate the mechanisms underlying the potential anti-cancer properties of apple peel extract.

Main Methods:

• Oral administration of apple peel extract to mice initiated with 7,12-dimethylbenz(a)anthracene and promoted with 12-O-tetradecanolyphorbol-13-acetate (TPA).
• Electron Spin Resonance (ESR) analysis to assess radical scavenging activity.
• Mechanistic studies involving JB6 cells and AP-1-luciferase reporter transgenic mice to evaluate inhibition of AP-1 transactivation and MAPK signaling (ERK and JNK).

Main Results:

• Apple peel extract significantly decreased the number of nonmalignant and malignant skin tumors per mouse.
• The extract demonstrated potent scavenging of hydroxyl (OH) and superoxide (O(2)(-)) radicals.
• Pretreatment with apple peel extract inhibited TPA- and ultraviolet B-induced AP-1 transactivation by blocking ERK and JNK activity.

Conclusions:

• Fresh apple peel extract exhibits chemopreventive effects against tumor promoter-induced skin carcinogenesis in mice.
• The observed chemopreventive effects are likely mediated by the extract's antioxidant properties, specifically by inhibiting reactive oxygen species-mediated AP-1 and MAPK pathway activation.