The cyclin-dependent kinase inhibitor, p21WAF1, promotes angiogenesis by repressing gene transcription of thioredoxin-binding protein 2 in cancer cells
The cyclin-dependent kinase inhibitor, p21WAF1, promotes angiogenesis by repressing gene transcription of thioredoxin-binding protein 2 in cancer cells
复制标题
DOI：
10.1093/carcin/bgp225
复制
发表时间：
2009-11-01
期刊：
影响因子：
4.7
通讯作者：
Marshall, Glenn M.
中科院分区：
文献类型：
--
作者：
Kuljaca, Selena;Liu, Tao;Marshall, Glenn M.
细胞周期蛋白依赖性激酶抑制剂p21（WAF 1）可诱导细胞周期停滞，并可作为肿瘤抑制剂。然而，越来越多的证据表明，p21（WAF 1）也可以增加对某些抗癌治疗的耐药性，从而促进肿瘤生长。解释这一悖论的机制尚未得到解释。我们发现，从MCF-7乳腺癌细胞转染p21（WAF 1）特异性小干扰RNA（siRNA）的条件培养基显着减少内皮细胞迁移，侵袭和血管发芽。条件培养基的液相色谱/质谱分析显示，p21（WAF 1）敲低显着减少硫氧还蛋白（Trx），一种氧化还原蛋白，已知促进肿瘤血管生成的分泌。p21（WAF 1）敲低通过影响细胞内硫氧还蛋白结合蛋白2（TBP 2）的表达水平而降低癌细胞中的Trx酶活性，已知TBP 2结合并抑制Trx。与这些发现一致，来自用TBP 2 siRNA转染的癌细胞的培养基促进内皮细胞侵袭并阻断p21（WAF 1）siRNA的抗血管生成作用。添加Trx siRNA阻断了TBP 2 siRNA的促血管生成作用。染色质免疫沉淀分析显示p21（WAF 1）结合TBP 2基因启动子。两者合计，我们的数据表明，p21（WAF 1）可以诱导Trx分泌和血管生成的癌细胞，直接转录抑制TBP 2启动子。
The cyclin-dependent kinase inhibitor, p21(WAF1), induces cell-cycle arrest and can act as a tumor suppressor. However, increasing evidence indicates that p21(WAF1) can also increase resistance to some anticancer therapies and thus promote tumor growth. The mechanisms explaining this paradox have not been explained. We found that conditioned media from MCF-7 breast cancer cells transfected with a p21(WAF1)-specific small interfering RNA (siRNA) significantly reduced endothelial cell migration, invasion and vascular sprouting. Liquid chromatography/mass spectrometry analysis of the conditioned media revealed that p21(WAF1) knockdown significantly reduced secretion of thioredoxin (Trx), a redox protein known to promote tumor angiogenesis. p21(WAF1) knockdown decreased Trx enzymatic activity in cancer cells, by effects on the expression levels of intracellular thioredoxin-binding protein 2 (TBP2), known to bind and inactivate Trx. Consistent with these findings, media from cancer cells transfected with TBP2 siRNA promoted endothelial cell invasion and blocked the anti-angiogenic effect of p21(WAF1) siRNA. Addition of Trx siRNA blocked the pro-angiogenic effects of TBP2 siRNA. Chromatin immunoprecipitation assays showed p21(WAF1) bound TBP2 gene promoter. Taken together, our data suggests that p21(WAF1) can induce Trx secretion and angiogenesis in cancer cells, by direct transcriptional repression of the TBP2 promoter.