Reichrath Sandra, Reichrath Jörg
Department of Dermatology; The Saarland University Hospital; Homburg/Saar, Germany.
Dermatoendocrinol. 2012 Jan 1;4(1):44-52. doi: 10.4161/derm.19027.
Notch signaling is of high importance for growth and survival of various cell types. We now analyzed the protein expression of two key components of the Notch signaling pathway (Notch-1, Jagged-1) in spontaneously immortalized (HaCaT) and in malignant (SCL-1) human keratinocytes, using western analysis. We found that Notch-1 and its corresponding ligand Jagged-1 are expressed in both cell lines, with no marked change following UV-B treatment. Moreover, treatment of both cell lines before or after UV-B irradiation with 1,25-dihydroxyvitamin D(3), the biologically active form of vitamin D, and/or epigenetic modulating drugs (TSA; 5-Aza) did not result in a marked modulation of the protein expression of Notch-1 or Jagged-1. Under the experimental conditions of this study, treatment with 1,25(OH)(2)D(3) protected human keratinocytes in part against the antiproliferative effects of UV-B-radiation. In conclusion, our findings do not point at a differential expression of these two key components of Notch signaling in non-malignant as compared to malignant human keratinocytes, indicating that alterations in their expression are not of importance for the photocarcinogenesis of human squamous cell carcinomas. Moreover, our findings do not support the hypothesis that modulation of Notch signaling may be involved in the photoprotective effect of 1,25-dihydroxyvitamin D(3), that we and others reported previously. Additionally, we demonstrate that epigenetic modulating drugs (TSA, 5-Aza) do not markedly modulate the expression Notch-1 or Jagged-1 in UV-B-treated human keratinocytes in vitro.
Notch信号通路对于多种细胞类型的生长和存活至关重要。我们现在使用蛋白质印迹分析，分析了Notch信号通路的两个关键成分（Notch-1、Jagged-1）在自发永生化的（HaCaT）和恶性的（SCL-1）人角质形成细胞中的蛋白质表达。我们发现，Notch-1及其相应配体Jagged-1在两种细胞系中均有表达，紫外线B处理后无明显变化。此外，在紫外线B照射之前或之后，用维生素D的生物活性形式1,25-二羟基维生素D(3)和/或表观遗传调节药物（曲古抑菌素A；5-氮杂胞苷）处理这两种细胞系，并未导致Notch-1或Jagged-1的蛋白质表达有明显调节。在本研究的实验条件下，用1,25(OH)(2)D(3)处理可部分保护人角质形成细胞免受紫外线B辐射的抗增殖作用。总之，我们的研究结果并未表明与恶性人角质形成细胞相比，Notch信号通路的这两个关键成分在非恶性人角质形成细胞中有差异表达，这表明它们表达的改变对人类鳞状细胞癌的光致癌作用并不重要。此外，我们的研究结果不支持Notch信号通路的调节可能参与我们和其他人之前报道的1,25-二羟基维生素D(3)的光保护作用这一假说。此外，我们证明表观遗传调节药物（曲古抑菌素A、5-氮杂胞苷）在体外不会显著调节紫外线B处理的人角质形成细胞中Notch-1或Jagged-1的表达。
