Hyaluronan-mediated CD44 interaction with RhoGEF and Rho kinase promotes Grb2-associated binder-1 phosphorylation and phosphatidylinositol 3-kinase signaling leading to cytokine (Macrophage-Colony stimulating factor) production and breast tumor progression
Hyaluronan-mediated CD44 interaction with RhoGEF and Rho kinase promotes Grb2-associated binder-1 phosphorylation and phosphatidylinositol 3-kinase signaling leading to cytokine (Macrophage-Colony stimulating factor) production and breast tumor progression
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DOI：
10.1074/jbc.m301885200
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发表时间：
2003-08-08
影响因子：
4.8
通讯作者：
Diedrich, F
中科院分区：
文献类型：
--
作者：
Bourguignon, LYW;Singleton, PA;Diedrich, F
在这项研究中，我们研究了CD 44（透明质酸（HA）受体）与RhoA特异性鸟嘌呤核苷酸交换因子（p115 RhoGEF）在人转移性乳腺肿瘤细胞（MDA-MB-231细胞系）的相互作用。免疫沉淀和免疫印迹分析表明，CD 44和p115 RhoGEF在MDA-MB-231细胞中表达，并且这两种蛋白质在体内作为复合物物理相关。HA与MDA-MB-231细胞的结合刺激p115 RhoGEF介导的RhoA信号传导和Rho激酶（ROK）活性，这反过来增加了衔接蛋白Gab-1（Grb 2相关结合物-1）的丝氨酸/苏氨酸磷酸化。磷酸化Gab-1促进PI 3-激酶募集至CD 44 v3。随后，PI 3-激酶被激活（特别是α、β、γ形式但不是δ形式的p110催化亚基），发生AKT信号传导，产生细胞因子（巨噬细胞集落刺激因子（M-CSF）），并且肿瘤细胞特异性表型（例如，G.肿瘤细胞生长、存活和侵袭）被上调。我们的研究结果还表明，HA/CD 44介导的致癌事件（例如，G. AKT活化、M-CSF产生和乳腺肿瘤细胞特异性表型）可被PI 3-激酶抑制剂（LY 294002）有效阻断。最后，我们发现显性阴性形式的ROK的过表达（通过用ROK的Rho结合结构域cDNA转染MBA-MD-231细胞）不仅抑制HA/CD 44介导的RhoA-ROK活化和Gab-1磷酸化，而且下调致癌信号传导事件（例如，G. Gab-1、PI 3-激酶-CD 44 v3结合、PI 3-激酶介导的AKT活化和M-CSF产生）和肿瘤细胞行为（e. G.细胞生长、存活和侵袭）。综上所述，这些发现强烈表明，CD 44与p115 RhoGEF和ROK的相互作用在促进Gab-1磷酸化导致Gab-1中起着关键作用。HA介导的乳腺癌进展过程中PI 3-激酶膜定位、AKT信号传导和细胞因子（M-CSF）产生。
In this study we have examined CD44 ( a hyaluronan ( HA) receptor) interaction with a RhoA-specific guanine nucleotide exchange factor ( p115RhoGEF) in human metastatic breast tumor cells (MDA-MB-231 cell line). Immunoprecipitation and immunoblot analyses indicate that both CD44 and p115RhoGEF are expressed in MDA-MB-231 cells and that these two proteins are physically associated as a complex in vivo. The binding of HA to MDA-MB-231 cells stimulates p115RhoGEF-mediated RhoA signaling and Rho kinase (ROK) activity, which, in turn, increases serine/threonine phosphorylation of the adaptor protein, Gab-1 (Grb2-associated binder-1). Phosphorylated Gab-1 promotes PI 3-kinase recruitment to CD44v3. Subsequently, PI 3-kinase is activated (in particular, alpha, beta, gamma forms but not the delta form of the p110 catalytic subunit), AKT signaling occurs, the cytokine (macrophage-colony stimulating factor (M-CSF)) is produced, and tumor cell-specific phenotypes ( e. g. tumor cell growth, survival and invasion) are up-regulated. Our results also demonstrate that HA/CD44-mediated oncogenic events ( e. g. AKT activation, M-CSF production and breast tumor cell-specific phenotypes) can be effectively blocked by a PI 3-kinase inhibitor (LY294002). Finally, we have found that overexpression of a dominant-negative form of ROK ( by transfection of MBA-MD-231 cells with the Rho-binding domain cDNA of ROK) not only inhibits HA/CD44-mediated RhoA-ROK activation and Gab-1 phosphorylation but also downregulates oncogenic signaling events ( e. g. Gab-1.PI 3-kinase-CD44v3 association, PI 3-kinase-mediated AKT activation, and M-CSF production) and tumor cell behaviors ( e. g. cell growth, survival, and invasion). Taken together, these findings strongly suggest that CD44 interaction with p115RhoGEF and ROK plays a pivotal role in promoting Gab-1 phosphorylation leading to Gab-1 . PI 3-kinase membrane localization, AKT signaling, and cytokine (M-CSF) production during HA-mediated breast cancer progression.