Integrin signal masks growth-promotion activity of HB-EGF in monolayer cell cultures
Integrin signal masks growth-promotion activity of HB-EGF in monolayer cell cultures
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DOI：
10.1242/jcs.054551
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发表时间：
2009-12-01
影响因子：
4
通讯作者：
Mekada, Eisuke
中科院分区：
文献类型：
--
作者：
Mizushima, Hiroto;Wang, Xiaobiao;Mekada, Eisuke
细胞外环境和组织结构有助于适当的细胞功能和生长控制。与体内生长的细胞相比，在标准聚苯乙烯组织培养板上单层生长的细胞在形状、生长速率和对外部刺激的反应方面有所不同。在这里，我们发现EGFR（表皮生长因子受体）配体肝素结合EGF样生长因子（HB-EGF）强烈刺激裸鼠的细胞生长，但在体外培养的细胞中则不然。我们探讨了 HB-EGF 在各种细胞培养条件下对细胞生长的影响，发现在细胞基质粘附减少的三维 (3D) 或二维 (2D) 培养系统中需要 HB-EGF 促进生长。在这种条件下，在不存在 HB-EGF 的情况下，细胞生长受到极大抑制，但在存在 HB-EGF 的情况下，细胞生长显着增强。当使用抗体或敲除整合素β1或粘着斑激酶（FAK）来减少整合素信号时，细胞表现出HB-EGF依赖性生长。我们还表明，EGF、转化生长因子 α (TGF α) 或其他受体酪氨酸激酶 (RTK) 的配体可刺激 3D 培养中的细胞生长，但不会刺激组织培养板中的细胞生长。这些结果表明，在不添加生长因子的情况下，整联蛋白信号足以支持二维组织培养板中的细胞生长，而在整联蛋白信号减弱的培养系统中清楚地证明了生长因子的刺激。
The extracellular environment and tissue architecture contribute to proper cell function and growth control. Cells growing in monolayers on standard polystyrene tissue culture plates differ in their shape, growth rate and response to external stimuli, compared with cells growing in vivo. Here, we showed that the EGFR (epidermal growth factor receptor) ligand heparin-binding EGF-like growth factor (HB-EGF) strongly stimulated cell growth in nude mice, but not in cells cultured in vitro. We explored the effects of HB-EGF on cell growth under various cell culture conditions and found that growth promotion by HB-EGF was needed in three-dimensional (3D) or two-dimensional (2D) culture systems in which cell-matrix adhesion was reduced. Under such conditions, cell growth was extremely suppressed in the absence of HB-EGF, but markedly potentiated in the presence of HB-EGF. When the integrin signal was reduced using antibodies or knockout of either integrin beta 1 or focal adhesion kinase (FAK), cells showed HB-EGF-dependent growth. We also showed that EGF, transforming growth factor alpha (TGF alpha) or ligands of other receptor tyrosine kinases (RTKs) stimulated cell growth in 3D culture, but not in tissue culture plates. These results indicate that the integrin signal was sufficient to support cell growth in 2D tissue culture plates without addition of the growth factor, whereas stimulation by growth factors was clearly demonstrated in culture systems in which integrin signals were attenuated.