Dynamic regulation of ROCK in tumor cells controls CXCR4-driven adhesion events
Dynamic regulation of ROCK in tumor cells controls CXCR4-driven adhesion events
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DOI：
10.1242/jcs.052167
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发表时间：
2010-02-01
影响因子：
4
通讯作者：
Worthylake, Rebecca A.
中科院分区：
文献类型：
--
作者：
Struckhoff, Amanda P.;Vitko, Jason R.;Worthylake, Rebecca A.
CXCR 4是一种趋化因子受体，通常在转移性肿瘤细胞上异常表达。为了研究肿瘤细胞粘附中的CXCR 4信号传导，我们在MCF 7乳腺肿瘤细胞中稳定过表达CXCR 4。细胞粘附试验表明，刺激受体与其配体，CXCL 12，促进粘附MCF 7-CXCR 4细胞的细胞外基质和内皮配体。为了更接近地模拟循环肿瘤细胞所经历的条件，我们在剪切应力条件下进行了附着测定。我们发现CXCL 12诱导的肿瘤细胞附着在流动下更加明显。ROCK是与粘附和转移相关的丝氨酸/苏氨酸激酶，其由CXCR 4信号转导调节。因此，我们研究了在CXC 12诱导的粘附事件中ROCK活性的贡献。我们的研究结果表明，双相调节的ROCK响应粘附。在初始附着期间，需要抑制ROCK活性。随后，粘附复合物的成熟和增强肿瘤细胞迁移需要ROCK活性的重新激活。有趣的是，CXCL 12部分降低了由附着产生的ROCK活性水平，这支持了一种模型，在该模型中，用CXCL 12刺激通过提供用于有效迁移的最佳水平的ROCK活性来调节肿瘤细胞粘附事件。
CXCR4 is a chemokine receptor often found aberrantly expressed on metastatic tumor cells. To investigate CXCR4 signaling in tumor cell adhesion, we stably overexpressed CXCR4 in MCF7 breast tumor cells. Cell attachment assays demonstrate that stimulation of the receptor with its ligand, CXCL12, promotes adhesion of MCF7-CXCR4 cells to both extracellular matrix and endothelial ligands. To more closely mimic the conditions experienced by a circulating tumor cell, we performed the attachment assays under shear stress conditions. We found that CXCL12-induced tumor cell attachment is much more pronounced under flow. ROCK is a serine/threonine kinase associated with adhesion and metastasis, which is regulated by CXCR4 signaling. Thus, we investigated the contribution of ROCK activity during CXC12-induced adhesion events. Our results demonstrate a biphasic regulation of ROCK in response to adhesion. During the initial attachment, inhibition of ROCK activity is required. Subsequently, re-activation of ROCK activity is required for maturation of adhesion complexes and enhanced tumor cell migration. Interestingly, CXCL12 partially reduces the level of ROCK activity generated by attachment, which supports a model in which stimulation with CXCL12 regulates tumor cell adhesion events by providing an optimal level of ROCK activity for effective migration.