UV-B-activated B16 melanoma cells or HaCaT keratinocytes accelerate signaling pathways associated with melanogenesis via ANGPTL 2 induction, an activity antagonized by Chrysanthemum extract

Abstract

Sunburn causes inflammation, which increases melanin production in skin and causes hyperpigmentation. Angiopoietin-like protein (ANGPTL) 2 is an inflammatory mediator induced in sun-exposed skin areas. However, whether ANGPTL2 functions in melanin production remains unclear. To assess this possibility, we overexpressed Angptl2 in the melanoma line B16 and in the keratinocyte line HaCaT. Relative to controls, Angptl2-expressing B16 cells produced higher melanin levels via tyrosinase induction. Accordingly, Angptl2-expressing HaCaT cells secreted relatively high levels of both endothelin-1 (ET-1) and α-melanocyte-stimulating hormone (α-MSH). Moreover, treatment with an extract from Chrysanthemum indicum × Erigeron annuus (CE) suppressed ANGPTL2 expression and repressed tyrosinase induction in melanocytes and of α-MSH and ET-1 in keratinocytes. Our data suggest that ANGPTL2 expression in keratinocytes and melanin-producing cells accelerates pigment production and that treatment of skin with a CE extract could prevent melanin accumulation.