The G protein-coupled receptor S1P2 regulates Rho/Rho kinase pathway to inhibit tumor cell migration
The G protein-coupled receptor S1P2 regulates Rho/Rho kinase pathway to inhibit tumor cell migration
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DOI：
10.1158/0008-5472.can-04-2311
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发表时间：
2005-05-01
期刊：
影响因子：
11.2
通讯作者：
Ferrer, F
中科院分区：
文献类型：
--
作者：
Lepley, D;Paik, JH;Ferrer, F
1-磷酸鞘氨醇 (SIP) 是一种溶血磷脂，可在细胞中发挥多种反应，如增殖、迁移和存活。这些效应由细胞表面的 G 蛋白偶联受体 (SIP1-5) 介导，可激活下游信号传导中间体，例如 Rac 和 Rho GTPases。 SIP 在人胶质母细胞瘤细胞中的作用机制尚未明确。 SIP 受体 (1-5) 和 SIP 代谢酶在三种人胶质母细胞瘤细胞系中表达。 SIP 对胶质母细胞瘤细胞迁移具有深远且不同的影响。用 SIP 处理的 U87 细胞显示出迁移显着增加，而 U118 和 U138 细胞系则受到强烈抑制。 SIP 介导的抑制与 SIP2 受体表达相关。 FTY720-P 是一种 SIP 类似物，可结合除 SIP2 之外的所有 SIP 受体，不会抑制胶质母细胞迁移。 SIP2的过度表达进一步抑制迁移，并且通过小干扰RNA阻断SIP2 mRNA表达逆转了抑制作用。与之前的报道相反，显示SIP2受体刺激对Rac活性和迁移的双模式调节，在天然细胞和过表达S1P的细胞中，Rac1和RhoA GTP酶均被SIP处理激活(2)。用 Rho 相关蛋白激酶 (ROCK) 抑制剂 Y-27632 处理 U118 细胞可恢复迁移，表明 ROCK 依赖性机制很重要。 SIP 刺激过度表达 β-半乳糖苷酶的 U118 细胞的肌动蛋白染色导致明显的应力纤维形成，这种形成因 SIP2 过度表达而加剧，被 SIP 部分阻断，或通过 Y-27632 预处理完全消除。这些数据提供了 SIP 通过 Rho 激酶依赖性途径抑制肿瘤细胞迁移的新机制的证据。
Sphingosine 1-phosphate (SIP) is a lysophospholipid that exerts a variety of responses in cells such as proliferation, migration, and survival. These effects are mediated by G protein-coupled receptors on the cell surface (SIP1-5), which activate downstream signaling intermediates such as Rac and Rho GTPases. Mechanisms of SIP action in human glioblastoma cells are not well defined. SIP receptors (1-5) and SIP-metabolizing enzymes were expressed in three human glioblastoma cell lines. SIP had a profound and differential effect on glioblastoma cell migration. U87 cells treated with SIP showed a significant increase in migration, whereas U118 and U138 cell lines were strongly inhibited. SIP-mediated inhibition correlated with SIP2 receptor expression. FTY720-P, an SIP analogue that binds all SIP receptors except SIP2, did not inhibit glioblastorna cell migration. Overexpression of SIP2 further suppressed migration, and blockage Of SIP2 mRNA expression by small interfering RNA reversed the inhibitory effect. Contrary to previous reports showing bimodal regulation of Rac activity and migration by SIP2 receptor stimulation, both Rac1 and RhoA GTPases were activated by SIP treatment in native cells and cells over-expressing S1P(2). Treatment of U118 cells with the Rho-associated protein kinase (ROCK) inhibitor Y-27632 restored migration suggesting that ROCK-dependent mechanisms are important. Actin staining of SIP stimulated U118 cells overexpressing beta-galactosidase resulted in pronounced stress fiber formation that was exacerbated by SIP2 overexpression, partially blocked by SIP,, or totally abolished by pretreatment with Y-27632. These data provide evidence of a novel mechanism of SIP inhibition of tumor cell migration via Rho kinase-dependent pathway.