Volume 18, Issue 1 pp. 50-56

Role of protein kinase C delta in X-ray-induced apoptosis of keratinocyte

Young-Sook Lee

Young-Sook Lee

Department of Dermatology and Research Institute for Medical Sciences, School of Medicine, Chungnam National University, Daejeon, Korea

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Kyung-Cheol Sohn

Kyung-Cheol Sohn

Department of Dermatology and Research Institute for Medical Sciences, School of Medicine, Chungnam National University, Daejeon, Korea

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Ki-Hwan Kim

Ki-Hwan Kim

Department of Radiation Oncology, School of Medicine, Chungnam National University, Daejeon, Korea

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Moon-June Cho

Moon-June Cho

Department of Radiation Oncology, School of Medicine, Chungnam National University, Daejeon, Korea

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Gang Min Hur

Gang Min Hur

Department of Pharmacology, School of Medicine, Chungnam National University, Daejeon, Korea

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Tae-Jin Yoon

Tae-Jin Yoon

Department of Dermatology, School of Medicine, Gyeongsang National University, Jinju, Korea

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Sung Kyu Kim

Sung Kyu Kim

Department of Therapeutic Radiology and Oncology, College of Medicine, Yeungnam University, Daegu, Korea

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Kyungmoon Lee

Kyungmoon Lee

Department of Dermatology and Research Institute for Medical Sciences, School of Medicine, Chungnam National University, Daejeon, Korea

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Jeung-Hoon Lee

Jeung-Hoon Lee

Department of Dermatology and Research Institute for Medical Sciences, School of Medicine, Chungnam National University, Daejeon, Korea

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Chang Deok Kim

Chang Deok Kim

Department of Dermatology and Research Institute for Medical Sciences, School of Medicine, Chungnam National University, Daejeon, Korea

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First published: 08 December 2008
Citations: 9
Chang Deok Kim, PhD, Department of Dermatology, School of Medicine, Chungnam National University, 55 Munhwa-ro, Daejeon 301-131, Korea, Tel.: +82 42 580 8346, Fax: +82 42 581 9475, e-mail: [email protected]

Abstract

Abstract: In this study, we investigated the process of X-ray-induced apoptosis of skin keratinocyte, and the functional role of protein kinase C delta (PKCδ) and downstream signalling cascade. High-dose X-ray irradiation (10 Gy) led to the apoptosis of HaCaT keratinocyte, accompanied by PKCδ cleavage. Treatment with PKCδ inhibitor and adenoviral transduction of dominant-negative PKCδ clearly inhibited the X-ray-induced apoptosis of keratinocyte. In addition, X-ray induced the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) and inhibition by ERK1/2 inhibitor abrogated the X-ray-induced apoptosis. Interestingly, overexpression of dominant-negative PKCδ markedly blocked the X-ray-induced phosphorylation of ERK1/2, suggesting that ERK1/2 is the functional downstream effector of PKCδ. Next, we investigated the difference between UVB and X-ray response. UVB induced the apoptosis of keratinocyte in a PKCδ-dependent manner, similar to X-ray response. However, UVB irradiation induced the phosphorylation of c-jun N-terminal kinases (JNK) and inhibition of JNK significantly protected the UVB-induced apoptosis. These results demonstrate that PKCδ is a key regulator in X-ray-induced apoptosis of keratinocyte and suggest that there is subtle difference in downstream signalling cascade between UVB and X-ray response of keratinocyte.

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