Chemokine CXCL12 activates dual CXCR4 and CXCR7-mediated signaling pathways in pancreatic cancer cells.
Chemokine CXCL12 activates dual CXCR4 and CXCR7-mediated signaling pathways in pancreatic cancer cells.
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DOI：
10.1186/1479-5876-10-68
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发表时间：
2012-04-02
影响因子：
7.4
通讯作者：
Kim J
中科院分区：
文献类型：
--
作者：
Heinrich EL;Lee W;Lu J;Lowy AM;Kim J
以前认为趋化因子CXCL12是趋化因子受体CXCR4的选择配体，现在已知趋化因子CXCL12可以激活CXCR4和CXCR7。然而，我们对这些受体在癌细胞中的共表达知之甚少。我们使用免疫组织化学来确定胰腺癌组织样本中的共表达程度，并使用免疫印迹来验证胰腺癌细胞系中的表达。在细胞培养研究中，在用CXCL12刺激细胞之前，使用siRNA敲低CXCR4、CXCR7、K-Ras和β-阻滞蛋白-2的表达。利用Raf-pull - down法和western blotting法评估丝裂原活化蛋白激酶途径（MAPK）的激活情况。受体参与cxcl12介导的细胞增殖增加，通过基于atp的增殖试验进行检测。首先，我们发现CXCR4/CXCR7在人胰腺癌组织和细胞系中频繁共表达。接下来，我们观察到，在共表达CXCR4/CXCR7的胰腺癌细胞系中，暴露于CXCL12或CXCL11 （CXCR7激动剂）后，ERK1/2磷酸化持续增加。为了更好地表征受体介导的途径，我们敲除CXCR4或CXCR7，将细胞暴露于CXCL12，并检测随后对ERK1/2的影响。我们观察到CXCR7介导了cxcl12驱动的ERK1/2磷酸化的增加。然而，敲低CXCR4表达，降低K-Ras活性水平。相反，KRAS敲低大大降低了cxcl12介导的ERK1/2磷酸化的增加。然后我们评估了β-arrestin-2的作用，这是一种由趋化因子受体直接募集的蛋白质。我们观察到β-arrestin-2敲低也抑制了由CXCR4和CXCR7介导的ERK1/2磷酸化的增加。最后，我们研究了cxcl12增强细胞增殖的机制，发现两种受体都可以调节细胞增殖。总之，我们的数据表明，CXCR4和CXCR7在人胰腺癌组织和细胞系中经常共表达。我们发现β-arrestin-2和K-Ras依赖通路协调CXCL12信号的转导。我们的研究结果表明，基于抑制CXCL12信号传导来阻止胰腺癌生长的治疗方法的发展应该集中在配体水平上，以解释这两种受体对这一信号通路的贡献。
Previously assumed to be a select ligand for chemokine receptor CXCR4, chemokine CXCL12 is now known to activate both CXCR4 and CXCR7. However, very little is known about the co-expression of these receptors in cancer cells. We used immunohistochemistry to determine the extent of co-expression in pancreatic cancer tissue samples and immunoblotting to verify expression in pancreatic cancer cell lines. In cell culture studies, siRNA was used to knock down expression of CXCR4, CXCR7, K-Ras and β-arrestin -2 prior to stimulating the cells with CXCL12. Activation of the mitogen-activated protein kinase pathway (MAPK) was assessed using both a Raf-pull down assay and western blotting. The involvement of the receptors in CXCL12-mediated increases in cell proliferation was examined via an ATP-based proliferation assay. First, we discovered frequent CXCR4/CXCR7 co-expression in human pancreatic cancer tissues and cell lines. Next, we observed consistent increases in ERK1/2 phosphorylation after exposure to CXCL12 or CXCL11, a CXCR7 agonist, in pancreatic cancer cell lines co-expressing CXCR4/CXCR7. To better characterize the receptor-mediated pathway(s), we knocked down CXCR4 or CXCR7, exposed the cells to CXCL12 and examined subsequent effects on ERK1/2. We observed that CXCR7 mediates the CXCL12-driven increase in ERK1/2 phosphorylation. Knockdown of CXCR4 expression however, decreased levels of K-Ras activity. Conversely, KRAS knockdown greatly reduced CXCL12-mediated increases in ERK1/2 phosphorylation. We then evaluated the role of β-arrestin-2, a protein directly recruited by chemokine receptors. We observed that β-arrestin-2 knockdown also inhibited increases in ERK1/2 phosphorylation mediated by both CXCR4 and CXCR7. Finally, we investigated the mechanism for CXCL12-enhanced cell proliferation and found that either receptor can modulate cell proliferation. In summary, our data demonstrate that CXCR4 and CXCR7 are frequently co-expressed in human pancreatic cancer tissues and cell lines. We show that β-arrestin-2 and K-Ras dependent pathways coordinate the transduction of CXCL12 signals. Our results suggest that the development of therapies based on inhibiting CXCL12 signaling to halt the growth of pancreatic cancer should be focused at the ligand level in order to account for the contributions of both receptors to this signaling pathway.
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影响因子：
56.9
作者：
Feng, Y;Broder, CC;Berger, EA
通讯作者：
Berger, EA
影响因子：
11.2
作者：
Marchesi, F;Monti, P;Allavena, P
通讯作者：
Allavena, P
DOI：
10.1073/pnas.2235846100
发表时间：
2003-11-11
影响因子：
11.1
作者：
Rubin, JB;Kung, AL;Segal, RA
通讯作者：
Segal, RA
影响因子：
29.4
作者：
Saur, D;Seidler, B;Schmid, RM
通讯作者：
Schmid, RM
影响因子：
4.4
作者：
Infantino, S;Moepps, B;Thelen, M
通讯作者：
Thelen, M