Department of Life and Medical Sciences, Chubu University Faculty of Life and Health Sciences, Matsumoto, Kasugai 487-8501, Japan; Department of Biochemistry II, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-ku, Nagoya 466-0065, Japan.
Department of Life and Medical Sciences, Chubu University Faculty of Life and Health Sciences, Matsumoto, Kasugai 487-8501, Japan.
Biochem Biophys Res Commun. 2014 Mar 7;445(2):504-10. doi: 10.1016/j.bbrc.2014.02.038. Epub 2014 Feb 15.
Although expression of gangliosides and their synthetic enzyme genes in malignant melanomas has been well studied, that in normal melanocytes has been scarcely analyzed. In particular, changes in expression levels of glycosyltransferase genes responsible for ganglioside synthesis during evolution of melanomas from melanocytes are very important to understand roles of gangliosides in melanomas. Here, expression of glycosyltransferase genes related to the ganglioside synthesis was analyzed using RNAs from cultured melanocytes and melanoma cell lines. Quantitative RT-PCR revealed that melanomas expressed high levels of mRNA of GD3 synthase and GM2/GD2 synthase genes and low levels of GM1/GD1b synthase genes compared with melanocytes. As a representative exogenous stimulation, effects of ultraviolet B (UVB) on the expression levels of 3 major ganglioside synthase genes in melanocytes were analyzed. Although direct UVB irradiation of melanocytes caused no marked changes, culture supernatants of UVB-irradiated keratinocytes (HaCaT cells) induced definite up-regulation of GD3 synthase and GM2/GD2 synthase genes. Detailed examination of the supernatants revealed that inflammatory cytokines such as TNFα and IL-6 enhanced GD3 synthase gene expression. These results suggest that inflammatory cytokines secreted from UVB-irradiated keratinocytes induced melanoma-associated ganglioside synthase genes, proposing roles of skin microenvironment in the promotion of melanoma-like ganglioside profiles in melanocytes.
尽管神经节苷脂及其合成酶基因在恶性黑色素瘤中的表达已得到充分研究，但在正常黑色素细胞中的表达却很少被分析。特别是，在黑色素瘤从黑色素细胞进化过程中，负责神经节苷脂合成的糖基转移酶基因表达水平的变化对于理解神经节苷脂在黑色素瘤中的作用非常重要。在这里，使用来自培养的黑色素细胞和黑色素瘤细胞系的 RNA 分析了与神经节苷脂合成相关的糖基转移酶基因的表达。定量 RT-PCR 显示，与黑色素细胞相比，黑色素瘤表达高水平的 GD3 合酶和 GM2/GD2 合酶基因的 mRNA，而 GM1/GD1b 合酶基因的表达水平较低。作为一种代表性的外源刺激，分析了紫外线 B（UVB）对黑色素细胞中 3 种主要神经节苷脂合酶基因表达水平的影响。尽管黑色素细胞的直接 UVB 照射没有引起明显的变化，但 UVB 照射的角质形成细胞（HaCaT 细胞）的培养上清液诱导了 GD3 合酶和 GM2/GD2 合酶基因的明确上调。对上清液的详细检查表明，TNFα 和 IL-6 等炎症细胞因子增强了 GD3 合酶基因的表达。这些结果表明，来自 UVB 照射的角质形成细胞分泌的炎症细胞因子诱导了黑色素瘤相关的神经节苷脂合酶基因，提出了皮肤微环境在促进黑色素细胞中类似于黑色素瘤的神经节苷脂谱中的作用。
