Induction of Apoptosis and Autophagy in UVB-Treated HaCaT Cells.
- Author:
Sang Don YOON
1
;
Won Ki BAEK
;
Sang Pyo KIM
;
Kyu Suk LEE
;
Jae We CHO
Author Information
1. Department of Dermatology, School of Medicine, Keimyung University, Daegu, Korea. janylove99@dsmc.or.kr
- Publication Type:Original Article
- Keywords:
Apoptosis;
Autophagy;
HaCaT cell;
UVB
- MeSH:
Apoptosis;
Autophagy;
Blotting, Western;
Caspase 3;
Cell Death;
Cell Line;
Down-Regulation;
Keratinocytes;
Up-Regulation
- From:Korean Journal of Dermatology
2013;51(8):600-607
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: UVB irradiation induces apoptosis or/and autophagy through several molecular pathways in keratinocytes. However, the precise molecular mechanism of UVB-induced autophagy is largely unknown in keratinocytes. OBJECTIVE: The purpose of this study was to investigate the molecular mechanisms of UVB-induced apoptosis and autophagy in HaCaT cell lines. METHODS: Cells were irradiated by UVB (Westinghouse FS-40 sunlamps) with various doses (0, 30, 60, 120, 240 mJ/cm2). The expression levels of caspase-3, Bax, Bcl2, Bcl-X(L) and LC3 were confirmed by Western blot analysis in UVB-irradiated HaCaT cell lines. Apoptotic cells were analyzed by PI staining, and autophagy cells were analyzed by immunofluorescent staining. RESULTS: The expression of Bcl-X(L) decreased from UVB 60 mJ/cm2 and Bcl2 decreased from UVB 240 mJ/cm2. The expression of caspase-3 was increased from UVB 120 mJ/cm2. These data showed that UVB-induced apoptosis is mediated by up-regulation of caspase-3 and down-regulation of Bcl2 and Bcl-X(L). Furthermore, the expression of LC3 increased from UVB 120 mJ/cm2. In addition, autophagy formation was observed in few fractions of apoptotic HaCaT cells in immunofluorescent staining; most apoptotic cells did not show autophagy formation. Moreover, autophagy formation inhibitor treatment induced a slight increment of apoptotic cell population under UVB irradiation. CONCLUSION: UVB irradiation induces not only apoptotic cell death but also autophagy formations; these events may create a defense mechanism for the prevention of apoptosis in UVB-treated HaCaT cells.
