Breast cancer cell migration is regulated through junctional adhesion molecule-A-mediated activation of Rap1 GTPase.
Breast cancer cell migration is regulated through junctional adhesion molecule-A-mediated activation of Rap1 GTPase.
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DOI：
10.1186/bcr2853
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发表时间：
2011-03-23
期刊：
影响因子：
--
通讯作者：
Hopkins AM
中科院分区：
文献类型：
--
作者：
McSherry EA;Brennan K;Hudson L;Hill AD;Hopkins AM
黏附蛋白连接黏附分子-A(JAM-A)调节上皮细胞的形态和迁移，其过度表达与乳腺癌患者转移风险增加有关。由于细胞迁移是肿瘤转移的早期要求，我们试图确定调控乳腺癌细胞迁移的JAM-A信号事件。MCF7乳腺癌细胞(表达高水平的内源性JAM-A)和乳腺癌患者的原代培养物用于本研究。使用siRNA在MCF7细胞中敲除JAM-A，以确定对细胞黏附、细胞迁移和各种整合素亚基蛋白表达的影响。由于我们之前已经证明了JAM-A的表达和β1-整合素之间的联系，我们研究了β1-整合素调节因子RAP1GTP酶在JAM-A被击倒或功能拮抗时的激活情况。为了测试JAM-A、RAP1和β1-整合素是否存在线性路径，我们在迁移分析中单独或一起测试了这三种蛋白质的功能抑制剂。最后，我们在MCF7细胞和原代乳腺细胞中进行免疫沉淀，以确定连接JAM-A和Rap1激活的结合伙伴。MCF7乳腺癌细胞中的JAM-A基因敲除减少了对β1整合素底物纤维连接蛋白的黏附和迁移。伴随着β1-整合素及其结合伙伴αV-和α5-整合素蛋白表达的降低。JAM-A基因被敲除或抑制后，RAP1的活性降低，药物抑制RAP1可减少MCF7细胞的迁移。同时抑制JAM-A、RAP1和β-1整合素后，未观察到相加的抗迁移作用，提示它们处于线性迁移途径。最后，为了阐明JAM-A与Rap1激活之间的结合伙伴，我们证明了JAM-A、AF-6和Rap1激活剂PDZ-GEF2在MCF7细胞和乳腺癌患者的原代培养中形成了复合体。我们的发现提供了令人信服的证据，证明JAM-A通过激活RAP1GTP酶和β1-整合素，在推动乳腺癌细胞迁移中发挥了新的作用。我们推测JAM-A在一些乳腺癌患者中的过度表达可能代表了降低转移可能性的新的治疗靶点。
The adhesion protein junctional adhesion molecule-A (JAM-A) regulates epithelial cell morphology and migration, and its over-expression has recently been linked with increased risk of metastasis in breast cancer patients. As cell migration is an early requirement for tumor metastasis, we sought to identify the JAM-A signalling events regulating migration in breast cancer cells. MCF7 breast cancer cells (which express high endogenous levels of JAM-A) and primary cultures from breast cancer patients were used for this study. JAM-A was knocked down in MCF7 cells using siRNA to determine the consequences for cell adhesion, cell migration and the protein expression of various integrin subunits. As we had previously demonstrated a link between the expression of JAM-A and β1-integrin, we examined activation of the β1-integrin regulator Rap1 GTPase in response to JAM-A knockdown or functional antagonism. To test whether JAM-A, Rap1 and β1-integrin lie in a linear pathway, we tested functional inhibitors of all three proteins separately or together in migration assays. Finally we performed immunoprecipitations in MCF7 cells and primary breast cells to determine the binding partners connecting JAM-A to Rap1 activation. JAM-A knockdown in MCF7 breast cancer cells reduced adhesion to, and migration through, the β1-integrin substrate fibronectin. This was accompanied by reduced protein expression of β1-integrin and its binding partners αV- and α5-integrin. Rap1 activity was reduced in response to JAM-A knockdown or inhibition, and pharmacological inhibition of Rap1 reduced MCF7 cell migration. No additive anti-migratory effect was observed in response to simultaneous inhibition of JAM-A, Rap1 and β1-integrin, suggesting that they lie in a linear migratory pathway. Finally, in an attempt to elucidate the binding partners putatively linking JAM-A to Rap1 activation, we have demonstrated the formation of a complex between JAM-A, AF-6 and the Rap1 activator PDZ-GEF2 in MCF7 cells and in primary cultures from breast cancer patients. Our findings provide compelling evidence of a novel role for JAM-A in driving breast cancer cell migration via activation of Rap1 GTPase and β1-integrin. We speculate that JAM-A over-expression in some breast cancer patients may represent a novel therapeutic target to reduce the likelihood of metastasis.
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影响因子：
11.2
作者：
Itoh, Masahiko;Nelson, Celeste M.;Bissell, Mina J.
通讯作者：
Bissell, Mina J.
DOI：
10.1016/j.bbrc.2009.01.100
发表时间：
2009-03-06
影响因子：
3.1
作者：
Gutwein, Paul;Schramme, Anja;Pfeilschifter, Josef
通讯作者：
Pfeilschifter, Josef
影响因子：
4
作者：
Humphries JD;Byron A;Humphries MJ
通讯作者：
Humphries MJ
影响因子：
24
作者：
Cavusoglu, Erdal;Kornecki, Elizabeth;Marmur, Jonathan D.
通讯作者：
Marmur, Jonathan D.
影响因子：
--
作者：
Brennan K;Offiah G;McSherry EA;Hopkins AM
通讯作者：
Hopkins AM