The Study of bcl-2 Expression by Retinoids in a Human Melanoma Cell Line

Bang, Sung Won; Park, Young Lip; Whang, Kyu Uang

Abstract

BACKGROUND: Apoptoss plays a major role in cellular proliferation and differentiation in tumor cells. Bcl-2, proto-oncogene, is known to inhibit apoptotic cell death of tumor cells. The high expression of bcl-2 in human melanoma cells over transforrned keratinocytes has been reported. The Loton group indicated that the growth of human melanoma cells exposed to retinoids was inhibit ed and their cellular melanin content incrensed over that of the untreated ce1Ls. The Veis group reported that bcl-2 defieient mice showed hypopigmented hair. Which suggests that bcl-2 may in volve melanogenesis. The Above mentioned findings may suggest that. bcl-2 and retinoids may play a role in melanoms biology.
OBJECTIVE
We under ook this study to elucidate a possible relationship between retinoids and bcl-2 expvessions in human melanoma cell lines.
METHODS
We analysed bcl-2 expressions from SK 28 cells(melanoma cell lines) after pretreat ment with retinoids using flow cytometry and imtnunoblotting.
RESULTS
1. In the results of the preliminary studies, we found that cultured human keratinocytes, fibro blasts and melanocytes n the resting state showed expressions of bcl-2. The latter showed a four fold expression of bcl-2. 2. Expression of bcl-2 was detected in SK 28, a human melanoma cell line, in the resting state. 3. After incubation with isotretinoin or etretinate treatment at 37 degrees C, for 48 hours, this treated group showed a more ir creased expression of bcl-2 than the control group.
CONCLUSION
Our data may explain that the mechanism of ret.inoids indur,ing inhibition of mela noma cell growth may be partly due to upregulation of bcl-2 expression. The high base-line ex pression of bcl-2 in melanoma cells may tell us why these pigment cells can survive against oxi dative products generated during melanogenesis.