CD44介导的α5β1整合素、皮层肌动蛋白和桩蛋白信号激活是基底样乳腺癌细胞与内皮细胞及富含纤连蛋白的基质黏附的基础。

CD44-mediated activation of α5β1-integrin, cortactin and paxillin signaling underpins adhesion of basal-like breast cancer cells to endothelium and fibronectin-enriched matrices.

作者信息

McFarlane Suzanne, McFarlane Cheryl, Montgomery Nicola, Hill Ashleigh, Waugh David J J

机构信息

Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, Northern Ireland, BT9 7BL, UK.

出版信息

Oncotarget. 2015 Nov 3;6(34):36762-73. doi: 10.18632/oncotarget.5461.

Abstract

CD44 expression is elevated in basal-like breast cancer (BLBC) tissue, and correlates with increased efficiency of distant metastasis in patients and experimental models. We sought to characterize mechanisms underpinning CD44-promoted adhesion of BLBC cells to vascular endothelial monolayers and extracellular matrix (ECM) substrates. Stimulation with hyaluronan (HA), the native ligand for CD44, increased expression and activation of β1-integrin receptors, and increased α5-integrin subunit expression. Adhesion assays confirmed that CD44-signalling potentiated BLBC cell adhesion to endothelium and Fibronectin in an α5B1-integrin-dependent mechanism. Co-immunoprecipitation experiments confirmed HA-promoted association of CD44 with talin and the β1-integrin chain in BLBC cells. Knockdown of talin inhibited CD44 complexing with β1-integrin and repressed HA-induced, CD44-mediated activation of β1-integrin receptors. Immunoblotting confirmed that HA induced rapid phosphorylation of cortactin and paxillin, through a CD44-dependent and β1-integrin-dependent mechanism. Knockdown of CD44, cortactin or paxillin independently attenuated the adhesion of BL-BCa cells to endothelial monolayers and Fibronectin. Accordingly, we conclude that CD44 induced, integrin-mediated signaling not only underpins efficient adhesion of BLBC cells to BMECs to facilitate extravasation but initiates their adhesion to Fibronectin, enabling penetrant cancer cells to adhere more efficiently to underlying Fibronectin-enriched matrix present within the metastatic niche.

摘要

CD44在基底样乳腺癌(BLBC)组织中的表达升高,并且与患者及实验模型中远处转移效率的增加相关。我们试图阐明CD44促进BLBC细胞与血管内皮单层及细胞外基质(ECM)底物黏附的机制。用CD44的天然配体透明质酸(HA)刺激,可增加β1整合素受体的表达和激活,并增加α5整合素亚基的表达。黏附试验证实,CD44信号传导以α5β1整合素依赖性机制增强BLBC细胞与内皮细胞及纤连蛋白的黏附。免疫共沉淀实验证实,HA促进了BLBC细胞中CD44与踝蛋白及β1整合素链的结合。敲低踝蛋白可抑制CD44与β1整合素的复合,并抑制HA诱导的、CD44介导的β1整合素受体激活。免疫印迹证实,HA通过CD44依赖性和β1整合素依赖性机制诱导皮层肌动蛋白和桩蛋白的快速磷酸化。单独敲低CD44、皮层肌动蛋白或桩蛋白均可减弱BL-BCa细胞与内皮单层及纤连蛋白的黏附。因此,我们得出结论,CD44诱导的整合素介导的信号传导不仅是BLBC细胞与脑微血管内皮细胞有效黏附以促进外渗的基础,而且启动了它们与纤连蛋白的黏附,使穿透性癌细胞能够更有效地黏附于转移龛中富含纤连蛋白的下层基质。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/f304/4742209/ad6cb8e94d29/oncotarget-06-36762-g001.jpg

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