Regulation of IGF-2 gene expression in human chondrosarcoma derived cell lines : HCS-2/8 and -2/A

人软骨肉瘤衍生细胞系中 IGF-2 基因表达的调节：HCS-2/8 和 -2/A

基本信息

批准号：
08672124
负责人：
TAKAHASHI Kojiro
金额：
$ 1.66万
依托单位：
Okayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

In chondrocytes without vascula, autocrine function of insulin-like growth factor-2 (IGF-2) is very important for the growth and differentiation. Regulation on the expression of IGF-2 gene (IGF-2) in human chondrosarcoma derived cell lines (HCS-2/8 and -2/A) was investigated in order to explore the function of IGF-2.In human chondrocytes, all four promoters of IGF-2 are expressed, and consensus binding sequenses to the transcriptional factors ; EGR1 (early growth response gene product 1), SP-1 (specificity protein-1) and WT1 (Wilms tumor suppresor), are localizing over the transcriptional regulation region of IGF-2 promoters. Although the expression of SP-1 is very slight in both of normal chondrocytes and HCS-2/8, EGR1 expression in HCS-2/8 was higher than that in normal chondrocytes and WT1 expression in HCS-2/8 was lower thatn that in normal chondrocytes. This suggests that the abnormal growth of chondrosarcoma-derived HCS-2/8 may be induced with the synergistic effect between a positive function of EGR1 and negative one of WT1 to the growth enhancement during the initial growth phase.The effects of ascorbic acid in HCS-2/8 were positive to the gene expression of IGF-2, H19 (tumore suppresor), EGR1, SP-1, WT1, type-10 collagen alpha1, aggrecan and alkaline phosphatase, but negative to that of type-2 collagen alpha1. These results suggest that the role of ascorbic acid in chondrocytes may be as a growth and differetiational factor during the phases to differentiation from growth.The imprinting status of IGF-2 in HCS-2/8 was paternal alleles for all the promoters, and seem to be independent directly on the excess gene expression. On CDKNIC (p57^<KIP2>) in the imprinting cluster over human chromosome 11p15.5 region, a lacking of PA in the PAPA-repeat was detected for the paternal allele in HCS-2/8, and the expressed allele was maternal.

在没有血管的软骨细胞中，胰岛素样生长因子2（IGF-2）的自分泌功能对于生长和分化非常重要。为了探讨IGF-2的功能，研究了人软骨肉瘤来源的细胞系（HCS-2/8和-2/A）中IGF-2基因（IGF-2）表达的调控。在人软骨细胞中，所有表达IGF-2的四个启动子，以及与转录因子的共有结合序列； EGR1（早期生长反应基因产物 1）、SP-1（特异性蛋白 1）和 WT1（Wilms 肿瘤抑制蛋白）位于 IGF-2 启动子的转录调控区域。虽然SP-1在正常软骨细胞和HCS-2/8中的表达都很轻微，但HCS-2/8中EGR1的表达高于正常软骨细胞，而HCS-2/8中WT1的表达低于正常软骨细胞。在正常软骨细胞中。这表明软骨肉瘤来源的HCS-2/8的异常生长可能是由EGR1的正功能和WT1的负功能之间的协同作用诱导的，以促进生长初期的生长。抗坏血酸在HCS中的作用-2/8 的 IGF-2、H19（肿瘤抑制因子）、EGR1、SP-1、WT1、10 型胶原蛋白 α1、聚集蛋白聚糖和碱性磷酸酶，但对 2 型胶原蛋白 α1 呈阴性。这些结果表明，抗坏血酸在软骨细胞中的作用可能是在从生长到分化的阶段中作为生长和分化因子。HCS-2/8中IGF-2的印记状态对于所有启动子来说都是父系等位基因，并且似乎直接独立于过量基因表达。在人类染色体 11p15.5 区域印记簇中的 CDKNIC (p57^<KIP2>) 上，检测到 HCS-2/8 中父本等位基因的 PAPA 重复序列中缺少 PA，并且表达的等位基因是母本。