Anti-cancer Activity and Mechanism of ADAMTS-1 Fragments

描述(申请人提供)：ADAMTS-1(带有血栓反应蛋白基序的去整合素和金属蛋白酶-1)含有金属蛋白酶和血栓反应蛋白I型(TSP-1)样基序，在器官发生、组织重塑和肿瘤发生中发挥重要作用。然而，ADAMTS-1的确切作用及其参与肿瘤生长和转移的潜在机制尚未确定。我们已经证明了ADAMTS-1经历了自动蛋白降解，全长ADAMTS-1和含有TSP-1结构域的ADAMTS-1片段分别显示了促肿瘤和抗肿瘤活性。全长ADAMTS-1可促进肝素结合的表皮生长因子(HB-EGF)和双调节蛋白(AR)跨膜前体的脱落，进而促进肿瘤细胞的增殖/存活和肿瘤血管生成，提示ADAMTS-1是一个有吸引力的肿瘤治疗靶点。相反，含有TSP-1结构域的ADAMTS-1片段具有较强的抗肿瘤活性和抑制可溶性HB-EGF和AR的活性。我们假设(1)全长ADAMTS-1通过脱落/激活HB-EGF和AR跨膜前体促进肿瘤细胞的增殖/存活和肿瘤血管生成，促进肿瘤生长和转移；(2)ADAMTS-1通过硫酸肝素蛋白多糖(HSPGs)通过间隔区直接或间接与其底物结合；(3)ADAMTS-1的间隔区可作为ADAMTS-1的主要负抑制因子；(4)ADAMTS-1片段的抗肿瘤活性位于TSP-1结构域，TSP-1通过抑制HB-EGF和AR等几种可溶性肝素结合生长因子的生物活性而发挥抗肿瘤活性。为了验证这些假设，我们将确定(1)ADAMTS-1间隔区中显示主要负抑制作用的区域和TSP-1结构域中包含抗肿瘤活性的确切片段；(2)包含TSP-1结构域的ADAMTS-1片段的主要负抑制作用和抗肿瘤活性的机制；以及3)来自该间隔区和TSP-1结构域的ADAMTS-1片段/Fc融合蛋白/肽是否可用作有效的抗肿瘤药物。我们已经建立了生化、分子和细胞生物学技术，以及进行拟议实验所必需的体内肿瘤生长和转移模型。这些结果将为ADAMTS-1是癌症治疗的重要靶点提供证据，并且ADAMTS-1片段/肽具有作为有效抗癌药物的潜力。

DESCRIPTION (provided by applicant): ADAMTS-1 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs-1) contains the metalloproteinase and thrombospondin type I (TSP-1) like motifs, and plays important roles in organogenesis, tissue remodeling, and tumorigenesis. However, the exact role of ADAMTS-1 and the underlying mechanism of its involvement in tumor growth and metastasis have not been established. We have shown that ADAMTS-1 undergoes auto-proteolytic cleavage and that full- length ADAMTS-1 and the ADAMTS-1 fragments that contain the TSP-1 domains display pro- and anti-tumor activity, respectively. Full-length ADAMTS-1 promotes shedding of heparin-binding EGF (HB-EGF) and amphiregulin (AR) transmembrane precursors, which in turn promote tumor cell proliferation/survival and tumor angiogenesis, suggesting that ADAMTS-1 is an attractive target for cancer therapy. On the contrary, the ADAMTS-1 fragments that contain the TSP-1 domains displayed potent anti-tumor activity and inhibit activity of soluble HB-EGF and AR. We hypothesize that (1) full-length ADAMTS-1 promotes tumor growth and metastasis by enhancing tumor cell proliferation/survival and tumor angiogenesis through shedding/activating HB-EGF and AR transmembrane precursors; (2) ADAMTS-1 binds to its substrates through the spacer domain directly or indirectly via heparin sulfate proteoglycans (HSPGs); (3) the spacer domain of ADAMTS-1 can be used as a dominant negative inhibitor of ADAMTS-1; and (4) anti-tumor activity of the ADAMTS-1 fragments resides in the TSP-1 domains which exert the anti-tumor activity by inhibiting bioactivity of several soluble heparin binding growth factors including HB- EGF and AR. To test these hypotheses, we will determine (1) the regions in the spacer domain of ADAMTS-1 that display dominant negative inhibitory effect and the exact segments in the TSP-1 domains that contain anti-tumor activity; (2) the mechanisms underlying the dominant negative inhibitory effect of the spacer domain and anti-tumor activity of the ADAMTS-1 fragments that contain the TSP-1 domains; and 3) whether the ADAMTS-1 fragments/Fc-fusion proteins/peptides derived from the spacer and the TSP-1 domains can be used as the effective anti-tumor agents. We have established the biochemical, molecular, and cell biology techniques and the in vivo tumor growth and metastasis models that are necessary to carry out the proposed experiments. The results obtained will provide the evidence to support that ADAMTS-1 is an important target for cancer therapy, and that the ADAMTS-1 fragments/peptides have potential to be used as the potent anti- cancer agents.