Oh Y
Department of Pediatrics, Oregon Health Sciences University, Portland 97201, USA.
Endocrine. 1997 Aug;7(1):111-3. doi: 10.1007/BF02778076.
The insulin-like growth factor binding proteins (IGFBPs) are a family of seven structurally homologous proteins that bind insulin-like growth factor 1 (IGF-I) and IGF-II with high affinity, thereby modu-lating the actions of IGFs. Several lines of recent evidence from various cell systems have suggested that IGFBPs, especially IGFBP-3, may play more active, IGF-independent, roles in growth regulation of cancer cells. In support of this hypothesis, the author has recently shown that IGFBP-3 binds specifically and with high affinity to the surface of various cell types and directly inhibits monolayer growth of these cells in an IGF-independent manner, presumably by specific interaction with cell membrane proteins that function as an IGFBP-3 receptor. The author's current studies demonstrate that a new class of IGFBP, IGFBP-7, constitutes a low affinity member of the IGFBP family, but primarily functions as a modulator of cell growth in an IGF-independent manner, similar to the action observed with IGFBP-3 in breast cancer cells. The author's studies on the mechanisms of action of the low affinity IGFBPs will provide insight into the IGF-independent actions of the classical high affinity IGFBPs and their impact on cancer cell growth.
胰岛素样生长因子结合蛋白（IGFBPs）是一个由七种结构同源蛋白组成的家族，它们以高亲和力结合胰岛素样生长因子1（IGF-I）和IGF-II，从而调节IGFs的作用。来自各种细胞系统的几条最新证据表明，IGFBPs，尤其是IGFBP-3，可能在癌细胞生长调节中发挥更积极的、不依赖IGF的作用。为支持这一假设，作者最近表明，IGFBP-3以高亲和力特异性结合各种细胞类型的表面，并以不依赖IGF的方式直接抑制这些细胞的单层生长，推测是通过与作为IGFBP-3受体起作用的细胞膜蛋白进行特异性相互作用。作者目前的研究表明，一类新的IGFBP，即IGFBP-7，是IGFBP家族的低亲和力成员，但主要以不依赖IGF的方式作为细胞生长的调节剂发挥作用，类似于在乳腺癌细胞中观察到的IGFBP-3的作用。作者对低亲和力IGFBPs作用机制的研究将深入了解经典高亲和力IGFBPs的不依赖IGF的作用及其对癌细胞生长的影响。
