Rubini M, Hongo A, D'Ambrosio C, Baserga R
Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Exp Cell Res. 1997 Feb 1;230(2):284-92. doi: 10.1006/excr.1996.3430.
The type 1 receptor for insulin-like growth factors (IGF-IR) plays an important role in the growth and transformation of several types of cells. We have investigated the role of IGF-IR number in IGF-I-mediated mitogenesis and transformation of mouse embryo fibroblasts. We have used R- cells (3T3-like cells originating from mouse embryos with a targeted disruption of the IGF-IR genes) transfected with a plasmid expressing the human IGF-IR cDNA to generate clones with receptor numbers ranging from zero to 10(6) receptors per cell. In this model, between 15,000 and 22,000 receptors per cell are sufficient to render mouse embryo cells competent to grow in serum-free medium supplemented solely with IGF-I. For growth in soft agar, 30,000 receptors per cell seem to be the minimum requirement. These experiments indicate that a small increment in the number of receptors per cell, well within the physiological range, can modulate the mitogenic and transforming activities of the IGF-IR in 3T3-like cells.
胰岛素样生长因子1型受体（IGF-IR）在多种细胞的生长和转化过程中发挥着重要作用。我们研究了IGF-IR数量在IGF-I介导的小鼠胚胎成纤维细胞有丝分裂和转化中的作用。我们使用了R-细胞（源自小鼠胚胎的3T3样细胞，其IGF-IR基因发生靶向破坏），用表达人IGF-IR cDNA的质粒进行转染，以产生每个细胞受体数量从零到10^6个受体不等的克隆。在这个模型中，每个细胞有15,000到22,000个受体就足以使小鼠胚胎细胞能够在仅添加IGF-I的无血清培养基中生长。对于在软琼脂中生长，每个细胞30,000个受体似乎是最低要求。这些实验表明，每个细胞受体数量在生理范围内的少量增加，就可以调节3T3样细胞中IGF-IR的有丝分裂和转化活性。
