Interactions of CD147 Involved in MMP Induction

描述(申请人提供)：细胞表面的IgSF蛋白CD147/EMMPRIN/basigin与瘤周基质细胞或其他肿瘤细胞结合，导致基质金属蛋白酶的产生，细胞外基质的降解，以及肿瘤侵袭和转移的增加。尽管CD147的文献越来越多(300篇发表在Medline上)，但相关的对抗性受体仍有待鉴定，并需要建立诱导基质金属蛋白酶和肿瘤调节功能的机制。我们现在定义了六个可能对CD147功能重要的分子靶点。这些靶点包括新的CD147受体拮抗剂分子、同源配体结合部位(在CD147的第一Ig结构域内)、整合素结合部位(第一Ig结构域)、小窝蛋白-1结合所需的部位(第二Ig结构域)、一个潜在的跨膜结构域相互作用部位以及参与MMP1诱导的细胞质结构域部位。我们建议严格测试这些靶点中的每一个在与其他蛋白质的协调关联、体外产生基质金属蛋白酶和体内致瘤性方面的重要性。首先，我们将鉴定和鉴定在基质金属蛋白酶-1和基质金属蛋白酶-2诱导过程中使用的CD147反式受体。其次，我们将确定抗受体结合和与o3j81整合素结合所需的CD147结构域1位点，然后我们将评估这些位点在基质金属蛋白酶-1和基质金属蛋白酶-2产生中的作用。第三，我们将利用结构域2突变体来验证CD147-小窝蛋白-L复合体通过阻止CD147糖基化和多聚化来抑制基质金属蛋白酶诱导的假说。第四，我们将研究高度保守的跨膜谷氨酸残基(E218)在蛋白质-蛋白质结合(包括单羧酸转运体结合)和CD147诱导基质金属蛋白酶功能中的作用。第五，CD147胞质尾巴将被用作探针，寻找对CD147功能至关重要的相关细胞内分子。第六，AIMS 2-5中定义和表征的关键突变体将在乳腺癌细胞系中表达，并在体外和体内原位小鼠模型中测试对肿瘤细胞的影响。我们对抗受体结合、基质金属蛋白酶诱导、细胞黏附、乳酸利用和小窝/微域组织的协调的新见解应该为更好地理解CD147对肿瘤细胞侵袭行为的戏剧性影响提供一个完整的框架。

DESCRIPTION (provided by applicant): The cell surface IgSF protein CD147/EMMPRIN/basigin, binds to peritumor stromal cells or to other tumor cells, leading to MMP production, extracellular matrix degradation, and elevated tumor invasion and metastasis. Despite the growing CD 147 literature (300 papers in Medline), relevant counter-receptors remain to be identified, and mechanisms for MMP induction and tumor regulatory functions need to be established. We now define six molecular targets likely to be important for CD 147 function. These targets include novel CD 147 counter-receptor molecules, the homophilic ligand binding site (within the first Ig domain of CD 147), integrin association site (first Ig domain), the site required for caveolin-1 association (second Ig domain), a potential transmembrane domain interaction site, and a cytoplasmic domain site involved in MMP "induction. We propose to rigorously test the importance of each of these target sites for coordinated associations with other proteins, for MMP production in vitro, and for tumorigenicity in vivo. First, we will identify and characterize the CD 147 counter-receptors utilized during MMP-1 and MMP-2 induction. Second, we will determine CD 147 domain 1 sites required for counter-receptor binding and association with o3j81 integrin, and then we will evaluate the role of these sites during MMP-1 and MMP-2 production. Third, we will utilize domain 2 mutants to test the hypothesis that CD147-caveolin-l complexes suppress MMP induction by preventing CD 147 glycosylation and multimerization. Fourth, we will investigate the role of a highly conserved transmembrane glutamic residue (E218) with respect to protein-protein associations (including monocarboxylate transporter association), and CD147 MMP-inducing functions. Fifth, the CD147 cytoplasmic tail will be used as a probe to search for associated intracellular molecules critical for CD147 functions. Sixth, key mutants defined and characterized in Aims 2-5 will be expressed in breast cancer cell lines and tested for effects on tumor cells in vitro and in orthotopic mouse models in vivo. Our new insights into the coordination of counter-receptor binding, MMP induction, cell adhesion, lactate utilization, and caveolin/microdomain organization should provide an integrated framework in which to better understand the dramatic effects of CD 147 on the invasive behavior of tumor cells.