Inhibition of Chemokine (CXC Motif) Ligand 12/Chemokine (CXC Motif) Receptor 4 Axis (CXCL12/CXCR4)-mediated Cell Migration by Targeting Mammalian Target of Rapamycin (mTOR) Pathway in Human Gastric Carcinoma Cells
Inhibition of Chemokine (CXC Motif) Ligand 12/Chemokine (CXC Motif) Receptor 4 Axis (CXCL12/CXCR4)-mediated Cell Migration by Targeting Mammalian Target of Rapamycin (mTOR) Pathway in Human Gastric Carcinoma Cells
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通过靶向哺乳动物雷帕霉素靶点 (mTOR) 途径抑制人胃癌细胞中趋化因子（CXC 基序）配体 12/趋化因子（CXC 基序）受体 4 轴 (CXCL12/CXCR4) 介导的细胞迁移
DOI：
10.1074/jbc.m111.302299
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发表时间：
2012-04-06
影响因子：
4.8
通讯作者：
Meng, Ling-Hua
中科院分区：
文献类型：
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作者：
Chen, Guang;Chen, Si-Meng;Meng, Ling-Hua
CXCL 12/CXCR 4在胃癌转移中起重要作用。已有报道雷帕霉素可抑制胃癌细胞的迁移。然而，mTOR通路在CXCL 12/CXCR 4介导的细胞迁移中的作用以及靶向PI 3 K/mTOR通路的药物的潜力仍未阐明。我们发现CXCL 12在MKN-45细胞中激活PI 3 K/Akt/mTOR通路。用CXCL 12刺激表达pEGFP-C1-Grp 1-PH融合蛋白的CHO-K1细胞导致产生磷脂酰肌醇（3，4，5）-三磷酸，这提供了CXCL 12激活PI 3 K的直接证据。siRNA下调p110 β而非p110 α可阻断CXCL 12诱导的Akt和S6 K1磷酸化。p110 β特异性抑制剂阻断了CXCL 12激活的PI 3 K/Akt/mTOR通路。此外，CXCL 12刺激后，抗p110 β抗体免疫沉淀的CXCR 4增加，G（i）蛋白抑制剂百日咳毒素消除了CXCL 12诱导的PI 3 K活化。进一步的研究表明，靶向PI 3 K/mTOR通路的抑制剂可显著阻断CXCL 12引发的MKN-45细胞的趋化反应，这可能主要归因于抑制mTORC 1，并与阻止F-actin重组以及下调活性RhoA、Rac 1和Cdc 42有关。此外，雷帕霉素抑制CXCL 12的分泌和CXCR 4的表达，这可能形成一个正反馈环，进一步消除导致细胞迁移的上游信号。最后，我们发现表达高水平cxcl 12的细胞对雷帕霉素敏感，因为它抑制迁移和增殖。总之，我们发现mTOR通路在CXCL 12/CXCR 4介导的细胞迁移中起重要作用，并提出靶向mTOR通路的药物可用于治疗高表达cxcl 12的转移性胃癌。
CXCL12/CXCR4 plays an important role in metastasis of gastric carcinoma. Rapamycin has been reported to inhibit migration of gastric cancer cells. However, the role of mTOR pathway in CXCL12/CXCR4-mediated cell migration and the potential of drugs targeting PI3K/mTOR pathway remains unelucidated. We found that CXCL12 activated PI3K/Akt/mTOR pathway in MKN-45 cells. Stimulating CHO-K1 cells expressing pEGFP-C1-Grp1-PH fusion protein with CXCL12 resulted in generation of phosphatidylinositol ( 3,4,5)-triphosphate, which provided direct evidence of activating PI3K by CXCL12. Downregulation of p110 beta by siRNA but not p110 alpha blocked phosphorylation of Akt and S6K1 induced by CXCL12. Consistently, p110 beta-specific inhibitor blocked the CXCL12-activated PI3K/Akt/mTOR pathway. Moreover, CXCR4 immunoprecipitated by anti-p110 beta antibody increased after CXCL12 stimulation and G(i) protein inhibitor pertussis toxin abrogated CXCL12-induced activation of PI3K. Further studies demonstrated that inhibitors targeting the PI3K/mTOR pathway significantly blocked the chemotactic responses of MKN-45 cells triggered by CXCL12, which might be attributed primarily to inhibition of mTORC1 and related to prevention of F-actin reorganization as well as down-regulation of active RhoA, Rac1, and Cdc42. Furthermore, rapamycin inhibited the secretion of CXCL12 and the expression of CXCR4, which might form a positive feedback loop to further abolish upstream signaling leading to cell migration. Finally, we found cells expressing high levels of cxcl12 were sensitive to rapamycin in its activity inhibiting migration as well as proliferation. In summary, we found that the mTOR pathway played an important role in CXCL12/CXCR4-mediated cell migration and proposed that drugs targeting the mTOR pathway may be used for the therapy of metastatic gastric cancer expressing high levels of cxcl12.