Thrombospondin-1 type 1 repeat recombinant proteins inhibit tumor growth through transforming growth factor-beta-dependent and -independent mechanisms.
Thrombospondin-1 type 1 repeat recombinant proteins inhibit tumor growth through transforming growth factor-beta-dependent and -independent mechanisms.
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发表时间：
2001-11
期刊：
影响因子：
11.2
通讯作者：
W. Miao;W. Seng;M. Duquette;P. Lawler;Christiane Laus;J. Lawler
中科院分区：
文献类型：
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作者：
W. Miao;W. Seng;M. Duquette;P. Lawler;Christiane Laus;J. Lawler
凝血酶敏感蛋白-1(TSP-1)是一种有效的肿瘤生长和血管生成抑制因子。利用合成肽已将TSP-1的抗血管生成活性定位于前胶原同源区和类型1重复序列(TSR)。为了阐明TSRs抑制肿瘤生长的分子机制，我们表达了这些基序的重组版本，并检测了它们对实验性B16F10黑色素瘤和Lewis肺癌的生长抑制能力。含有三个TSR(3TSR)或第二个TSR(TSR2+RFK)或不含转化生长因子-β(TGFbeta)激活序列(RFK)的重组蛋白已在果蝇S2细胞中表达。此外，还制备了在第二个TSR的RFK序列(TSR2+QFK)或WSHWSPW序列[TSR2(W/T)]发生突变的重组蛋白。与血小板TSP-1类似，这些蛋白是内皮细胞迁移的有效抑制因子，人TSP-1的3TSR(3TSR/hTSP-1)和TSR2+RFK激活TGFβ。重组3TSR/hTSP-1 2.5 mg(135 Nmol)/kg/d对B16F10肿瘤生长的抑制率为81%。TSR2+RFK 2.5 mg(360nmol)/kg/天的抑制作用与之相当。相比之下，小鼠TSP-2(3TSR/mTSP-2)、TSR2+QFK和TSR2的3TSR效果明显较差。TSR2+RFK和TSR2降低肿瘤血管密度，但TSR2+RFK对B16F10肿瘤细胞凋亡和增殖的影响更大。同时用TSR2+RFK和可溶性形式的TGFbeta受体或活性TGFbeta的抗体治疗B16F10肿瘤小鼠，可将对B16F10肿瘤生长的抑制降低到与TSR2和TSR2+QFK相当的水平。相反，TGFbeta激活序列的存在并不增加对Lewis肺癌实验性肿瘤生长的抑制水平。这些数据表明，TSRs通过抑制血管生成、调节肿瘤细胞生长和凋亡来抑制肿瘤生长。肿瘤细胞生长和凋亡的调节依赖于转化生长因子β，而对血管生成的抑制则不是。
Thrombospondin-1 (TSP-1) is a potent inhibitor of tumor growth and angiogenesis. The antiangiogenic activity of TSP-1 has been mapped to the procollagen homology region and the type 1 repeats (TSR) using synthetic peptides. To elucidate the molecular mechanisms that are involved in the inhibition of tumor growth by the TSRs, we have expressed recombinant versions of these motifs and have assayed their ability to inhibit the growth of experimental B16F10 melanomas and Lewis lung carcinomas. Recombinant proteins that contain all three TSRs (3TSR) or the second TSR with (TSR2+RFK) or without (TSR2) the transforming growth factor-beta (TGFbeta) activating sequence (RFK) have been expressed in Drosophila S2 cells. In addition, recombinant proteins with mutations in either the RFK sequence (TSR2+QFK) or the WSHWSPW sequence [TSR2 (W/T)] of the second TSR have been prepared. Similar to platelet TSP-1, these proteins are potent inhibitors of endothelial cell migration, and 3TSR of human TSP-1 (3TSR/hTSP-1) and TSR2+RFK activate TGFbeta. An 81% inhibition of B16F10 tumor growth is observed at 2.5 mg (135 nmol)/kg/day of the recombinant 3TSR/hTSP-1. A comparable level of inhibition is observed with 2.5 mg (360 nmol)/kg/day of TSR2+RFK. By contrast, 3TSR of mouse TSP-2 (3TSR/mTSP-2), TSR2+QFK, and TSR2 are significantly less effective. TSR2+RFK and TSR2 reduce tumor vessel density, but TSR2+RFK has a greater effect on B16F10 tumor cell apoptosis and proliferation. Concurrent treatment of B16F10 tumor-bearing mice with TSR2+RFK and either a soluble form of the TGFbeta receptor or an antibody to active TGFbeta reduces the inhibition of B16F10 tumor growth to levels that are comparable with those of TSR2 and TSR2+QFK. By contrast, the presence of the TGFbeta-activating sequence does not increase the level of inhibition of Lewis lung carcinoma experimental tumor growth. These data indicate that the TSRs inhibit tumor growth by inhibition of angiogenesis and regulation of tumor cell growth and apoptosis. The regulation of tumor cell growth and apoptosis is TGFbeta dependent, whereas the inhibition of angiogenesis is not.