DOMINANT-NEGATIVE INHIBITION OF TUMORIGENESIS IN-VIVO BY HUMAN INSULIN-LIKE GROWTH-FACTOR-I RECEPTOR MUTANT
DOMINANT-NEGATIVE INHIBITION OF TUMORIGENESIS IN-VIVO BY HUMAN INSULIN-LIKE GROWTH-FACTOR-I RECEPTOR MUTANT
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DOI：
10.1073/pnas.91.6.2181
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发表时间：
1994-03-15
影响因子：
11.1
通讯作者：
MELMED, S
中科院分区：
文献类型：
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作者：
PRAGER, D;LI, HL;MELMED, S
尽管胰岛素样生长因子I（IGF-I）是一种促有丝分裂生长因子，但其在肿瘤发生中的作用尚不清楚。因此，我们将野生型和截短的β亚基突变体((STOP)-S-952)人IGF-I受体cDNA转染至Rat-1成纤维细胞中。 Rat-1 转染子表达的 IGF-I 受体质量增加了 2.5 至 7 倍，而 IGF-I 结合的 K-d 没有变化。转染野生型受体cDNA的Rat-1细胞通过增加增殖和DNA合成对体外IGF-I处理作出反应。过表达野生型受体的细胞也被转化，如软琼脂中配体依赖性集落增殖所证明的那样。注射到无胸腺裸鼠后，al！野生型转染子在 3 周内形成实体肉瘤，离体肿瘤细胞测定证实人类 IGF-I 受体持续过度表达。相反，(STOP)-S-952转染细胞的DNA合成和增殖均减弱，低于未转染细胞。 (STOP)-S-952 细胞在体外对 IGF-I 无反应，并且无法维持不依赖贴壁的生长。尽管(STOP)-S-952转染细胞上存在明显的内源IGF-I受体，但将(STOP)-S-952转染子注射到无胸腺小鼠后长达8周，没有诱导出肿瘤。因此，(STOP)-S-952 可能是通过组装无功能的杂合大鼠/突变人受体四聚体而充当内源性 IGF-I 受体功能的显性失活抑制剂。
Although insulin-like growth factor I(IGF-I) is a mitogenic growth factor, its role in tumorigenesis is unclear. We therefore transfected wild-type and truncated beta-subunit mutant ((STOP)-S-952) human IGF-I receptor cDNAs into Rat-1 fibroblasts. Rat-1 transfectants expressed 2.5- to 7-fold increased IGF-I receptor mass, while the K-d for IGF-I binding was unchanged. The Rat-1 cells transfected with wild-type receptor cDNA responded to in vitro IGF-I treatment by increased proliferation and DNA synthesis. Cells overexpressing wild-type receptors were also transformed as evidenced by ligand-dependent colony proliferation in soft agar. After injection into athymic nude mice, al! wild-type transfectants formed solid sarcomas within 3 weeks, and ex vivo tumor cell assays confirmed continued overexpression of human IGF-I receptors. In contrast, both DNA synthesis and proliferation of (STOP)-S-952-transfected cells were attenuated below that of untransfected cells. (STOP)-S-952 cells were nonresponsive to IGF-I in vitro and were unable to sustain anchorage-independent growth. No tumors were induced for up to 8 weeks after injection of (STOP)-S-952 transfectants into athymic mice, despite the presence of demonstrable endogenous IGF-I recep tors on the (STOP)-S-952-transfected cells. Therefore, (STOP)-S-952 behaves as a dominant negative inhibitor of endogenous IGF-I receptor function, probably by assembling nonfunctional hybrid rat/mutant human receptor tetramers.