Koyama H, Nishizawa Y, Hosoi M, Fukumoto S, Kogawa K, Shioi A, Morii H
Second Department of Internal Medicine, Osaka City University Medical School, Japan.
Circ Res. 1996 Oct;79(4):757-64. doi: 10.1161/01.res.79.4.757.
The effect of an angiogenesis inhibitor, TNP-470, on DNA synthesis and its underlying signaling cascades stimulated by platelet-derived growth factor (PDGF)-BB and insulin-like growth factor (IGF)-I were examined in bovine vascular smooth muscle cells (SMCs). PDGF-BB (10 ng/mL)- and IGF-I (100 ng/mL)-stimulated increase in DNA synthesis was completely abolished by simultaneous treatment with TNP-470 (1.0 ng/mL). TNP-470 had no effects on PDGF receptor autophosphorylation or early signal transduction, such as activation of mitogen-activated protein kinase and immediate early gene expression. PDGF-BB induced an increase in mRNA levels of cyclin D1, cyclin-dependent kinase (cdk) 4, and cdk2, as well as the activity of cdk2, which preceded the G1/S boundary, as estimated by the kinetics of DNA synthesis. The PDGF-BB-induced activation of cdk2 was inhibited by TNP-470, which was correlated with decreased cdk2 mRNA levels. In contrast, TNP-470 had no or less marked effect on cyclin D1 and cdk4 mRNA levels induced by PDGF-BB. TNP-470 also inhibited a much smaller increase in cdk2 mRNA levels and activation stimulated by IGF-I. In conclusion, TNP-470 potently inhibits DNA synthesis of SMCs, and this inhibition is associated with decreased levels of cdk2 mRNA and activity.
在牛血管平滑肌细胞（SMC）中，研究了血管生成抑制剂TNP - 470对由血小板衍生生长因子（PDGF）-BB和胰岛素样生长因子（IGF）-I刺激的DNA合成及其潜在信号级联反应的影响。同时用TNP - 470（1.0 ng/mL）处理可完全消除PDGF - BB（10 ng/mL）和IGF - I（100 ng/mL）刺激引起的DNA合成增加。TNP - 470对PDGF受体自身磷酸化或早期信号转导没有影响，如丝裂原活化蛋白激酶的激活和立即早期基因表达。根据DNA合成动力学估计，PDGF - BB诱导细胞周期蛋白D1、细胞周期蛋白依赖性激酶（cdk）4和cdk2的mRNA水平增加，以及cdk2的活性增加，这些变化先于G1/S边界出现。TNP - 470抑制了PDGF - BB诱导的cdk2激活，这与cdk2 mRNA水平降低相关。相比之下，TNP - 470对PDGF - BB诱导的细胞周期蛋白D1和cdk4 mRNA水平没有或只有较小的显著影响。TNP - 470也抑制了IGF - I刺激引起的cdk2 mRNA水平和活性的较小增加。总之，TNP - 470有效抑制SMC的DNA合成，这种抑制与cdk2 mRNA水平和活性降低有关。
