A Role of HMGIC in Squamous Carcinoma Cells of The Oral Cavity

在先前的研究中，我们发现转录因子高迁移率族蛋白(HMGIC/HMGA2)在口腔癌中的表达频繁，并与患者的5年生存率有关。了解HMGIC表达的作用应该扩大对癌症进展的分子机制(S)的知识。为此，我们开发了一种新的高通量分析方法，称为SChIP，用于揭示HMGA2靶基因。我们确定了大约。100个基因，集中在5个不同的基因上，这些基因有望参与口腔癌的进展。RT-PCR结果显示，这5个基因在分化的HaCaT角质形成细胞中几乎不表达，而在未分化的HaCaT细胞中表达上调。此外，未表达HMGIC基因的口腔癌细胞(KOSC3、Ho1u1)不表达这5个基因，而表达HMGIC基因的口腔癌细胞(HOC313、TSU)则不表达这5个基因。为了了解HMGIC的转录活性，我们目前正在通过荧光素酶系统的报告分析来研究它。HMGIC靶基因在从缺氢小鼠分离的角质形成细胞中的表达也在调查中。我们将建立通过RNAi特异性击倒HMGA2基因的癌细胞株，并分析HMGIC和靶基因对肿瘤的致瘤性、侵袭性、转移潜能和表型变化的直接作用。

In a previous study, we showed that expression of a transcription factor-high mobility group protein (HMGIC/HMGA2), which plays a critical role in differentiation and growth of un-differentiated mesenchymal cells during development, is frequently observed in oral carcinomas and associates with 5-year survival rate of patients suffered from the disease. Understanding a role of HMGIC expression should expand knowledge of a molecular mechanism(s) of cancer progression. In this end, we developed a novel high-throughput analysis, named sChIP, to unveil HMGA2 target genes. We identified approx. 100 genes, and focused on 5 different genes, which are expected to be involved in the progression of oral carcinomas. RT-PCR showed that expression of these 5 genes were negligible in differentiated HaCaT keratinocytes but upregulated in undifferentiated HaCaT cells. In addition, oral carcinoma cells without HMGIC expression (KOSC3, Ho1u1) did not express these 5 genes in contrast to the expression in carcinoma cells expressing HMGIC gene (HOC313, TSU). To understand the transcriptional activity of HMGIC, we are currently investigating it by a reporter assay using luciferase system. Expression of HMGIC target genes in keratinocytes isolated from Hmgic-null mice is also under investigation. We will develop carcinoma cell lines which are specifically knock-downed HMGA2 gene by RNAi, and analyze a direct role of HMGIC and the target genes on tumorgenisity, and invasiveness, metastatic potential and phenotypic alterations of carcinoma cells.