Rac1-MKK3-p38-MAPKAPK2 pathway promotes urokinase plasminogen activator mRNA stability in invasive breast cancer cells
Rac1-MKK3-p38-MAPKAPK2 pathway promotes urokinase plasminogen activator mRNA stability in invasive breast cancer cells
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DOI：
10.1074/jbc.m209542200
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发表时间：
2002-12-13
影响因子：
4.8
通讯作者：
Huang, S
中科院分区：
文献类型：
--
作者：
Han, QW;Leng, J;Huang, S
我们先前报道，下调或功能性阻断α v整联蛋白抑制侵袭性MDA-MB-231乳腺癌细胞中的内源性p38丝裂原活化蛋白激酶（MAPK）活性和尿激酶纤溶酶原激活物（uPA）表达，而使α v整联蛋白与玻连蛋白接合激活p38 MAPK并上调uPA表达（Chen，J.，巴斯克维尔角，汉，Q，潘兹，和Huang，S.（2001）J.Biol.Chem.276，47901-47905）。目前，p38 MAPK的上下游信号分子介导α v整合素介导的uPA上调尚不清楚。在本研究中，我们发现α v整合素连接优先激活小G蛋白Rac 1，显性负性Rac 1抑制α v整合素介导的p38 MAPK激活。使用组成型活化的MAPK激酶，我们发现组成型活化的MKK 3和MKK 6突变体都能够激活p38 MAPK并上调uPA表达，但只有显性失活的MKK 3阻断α v整合素介导的p38 MAPK激活和uPA上调。这些结果表明，MKK 3，而不是MKK 6，介导α v整联蛋白诱导的p38 MAPK激活。在p38 MAPK的潜在下游效应子中，我们发现只有MAPK活化的蛋白激酶2显著影响α v整合素介导的uPA上调。最后，我们利用含有uPA mRNA 3 '-非翻译区（UTR）和腺苷尿苷富集区（3'-UTR）的β-珠蛋白报告基因构建体，证明p38 MAPK/MAPK激活的蛋白激酶2信号通路通过uPA mRNA 3 '-UTR中的腺苷/尿苷富集区序列调控uPA mRNA的稳定性。
We reported previously that down-regulating or functionally blocking alphav integrins inhibits endogenous p38 mitogen-activated protein kinase (MAPK) activity and urokinase plasminogen activator (uPA) expression in invasive MDA-MB-231 breast cancer cells whereas engaging av integrins with vitronectin activates p38 MAPK and up-regulates uPA expression (Chen, J., Baskerville, C., Han, Q., Pan, Z., and Huang, S. (2001) J. Biol. Chem. 276, 47901-47905). Currently, it is not clear what upstream and downstream signaling molecules of p38 MAPK mediate alphav integrin-mediated uPA up-regulation. In the present study, we found that av integrin ligation activated small GTPase Rac1 preferentially, and dominant negative Rac1 inhibited av integrin-mediated p38 MAPK activation. Using constitutively active MAPK kinases, we found that both constitutively active MKK3 and MKK6 mutants were able to activate p38 MAPK and up-regulate uPA expression, but only dominant negative MKK3 blocked alphav integrin-mediated p38 MAPK activation and uPA up-regulation. These results suggest that MKK3, rather than MKK6, mediates av integrin-induced p38 MAPK activation. Among the potential downstream effectors of p38 MAPK, we found that only MAPK-activated protein kinase 2 affects alphav integrin-mediated uPA up-regulation significantly. Finally, using beta-globin reporter gene constructs containing uPA mRNA 3'-untranslated region (UTR) and adenosineturidine-rich elements-deleted 3'-UTR, we demonstrated that p38 MAPK/MAPK-activated protein kinase 2 signaling pathway regulated uPA mRNA stability through a mechanism involving the adenosine/uridine-rich elements sequence in 3'-UTR of uPA mRNA.