Effect of Hypoxia on the Melanogenesis of Murine B16 Melanoma Cells

Song, Young Gil; Yang, Jeong Yeh; Koo, Jeung Hyun; Yoon, Ha Yong; Lee, Seung Yong; Yun, Seok Kweon; Park, Byung Hyun; Kim, Han Uk; Park, Jin Woo

Abstract

BACKGROUND: Numerous reports suggest the role of oxygen in melanogenesis. However, little has been reported on the effect of a hypoxic environment on cellular melanogenesis.
OBJECTIVE
The effect of low oxygen tension on cellular melanogenesis was investigated in B16 murine melanoma cells.
METHODS
Using cells cultured under an ambient (21% O2) or hypoxic (5% O2) condition, melanin content and tyrosinase activity were measured spectrophotometrically. The expression of tyrosinase, tyrosinase-related protein (TRP)- 1, and TRP-2 were analyzed by RT-PCR and Western blot.
RESULTS
Culture of cells under hypoxic conditions caused significant inhibition of isobutylmethylxanthine (IBMX)- induced increase of melanin content. No cytotoxicity was observed during the hypoxic culture periods. Decreased melanin content occurred through the decrease of tyrosinase protein and activity (p<0.01). The mRNA levels of tyrosinase and TRP-2 were also decreased by hypoxia, while that of TRP-1 was unchanged. Similar inhibitions of melanin content and tyrosinase activity were observed in the cells stimulated with dibutyryl-cAMP.
CONCLUSION
IBMX-induced melanogenesis in B16 cells was significantly inhibited under hypoxic culture conditions, suggesting the important role of oxygen tension in cellular melanogenesis.