INVERSE METASTATIC MODALITIES BY HEPARANASES

描述(由申请人提供)：细胞表面硫酸乙酰肝素蛋白多糖(HSPG)作为促进或防止肿瘤进展的诊断工具的直接证据一直缺乏。其他人和我们已经证明，乙酰肝素酶(HPA-1)是侵袭和转移事件的关键决定因素，并在特定的链内位置裂解HSPG的HS链。虽然HPA-1代表了哺乳动物HS降解酶的第一个纯化和克隆的例子，但最近已经克隆了一个与HPA-1相关的基因(HPA-2)，并将基因产物命名为乙酰肝素酶-2或HPA-2。由于能够接触到新开发的HPA-2和HPA-1分子探针，我们一直在研究乙酰肝素酶在脑转移性黑色素瘤(BMM)模型中作为纯化酶、抗原和基因的机制。我们发现，与相应的HPA-1暴露相比，BMM细胞的HPA-2处理对脑定植的影响相反。 我们的中心假设是乙酰肝素酶/HSPG处理在侵袭和转移中起关键作用，并且是抗癌治疗的靶点。这一应用的假设是：1)肿瘤细胞表面HS含有影响黑色素瘤生长和脑转移形成的生物活性序列，2)HSPG的HS链被肝素酶选择性降解后，作为BMM的隐蔽抑制剂或促进剂。这项拟议的工作解决了NC.I.脑瘤PRG报告提出的研究重点，以更好地理解脑转移瘤建立和扩散的潜在机制。我们计划通过追求以下具体目标来证明我们的假设： 1.研究HPA-2在脑转移性黑色素瘤(BMM)中的表达特征及其与HPA-1和患者预后的关系。 2.确定肝素酶降解HS的不同专一性导致抑制或促进脑转移的机制。这些研究将断言1)乙酰肝素酶(特别是HPA-2)在癌症生物学中的相关性，以及2)HS链作为黑色素瘤生长和转移的促进剂或抑制剂的重要性，特别是对大脑。它们将为开发以多糖为基础的抗癌分子提供一个框架，作为重要的预后工具和转移检测、诊断和治疗的诊断筛查。

DESCRIPTION (provided by applicant): Direct evidence of cell-surface heparan sulfate proteoglycans (HSPG) as diagnostic tools for promoting or preventing tumor progression has been lacking. Others and we have demonstrated that heparanase (Hpa-1) is a key determinant in invasive and metastatic events, and cleaves the HS chains of HSPG at specific intrachain sites. Although Hpa-1 represents the first example of purification and cloning of a mammalian HS degradative enzyme, a gene (hpa-2) related to hpa-1 has been recently cloned, and the gene product named heparanase-2 or Hpa-2. Being in the unique position of having access to newly developed Hpa-2 and Hpa-1 molecular probes, we have been studying mechanisms of heparanases in brain-metastatic melanoma (BMM) models as purified enzymes, antigens, and genes. We have found that Hpa-2 treatment of BMM cells results in opposite effects on brain colonization when compared to a corresponding Hpa-1 exposure. Our central hypothesis is that heparanases/HSPG processing is critical in invasion and metastasis, and targets for anti-cancer therapeutics. Hypotheses for this application are: 1) tumor cell surface HS contain bioactive sequences that impinge on melanoma growth and brain metastasis formation, and 2) HS chains from HSPG act as cryptic inhibitors or promoters of BMM upon their selective degradation by heparanases. The work proposed addresses research priorities raised by the N.C.I. Brain Tumor PRG report for an improved understanding of mechanisms underlying the establishment and spread of brain metastasis. We plan to demonstrate our hypotheses by pursuing the following specific aims: 1. To characterize Hpa-2 expression modalities in brain-metastatic melanoma (BMM) and relate them to Hpa-1 and to patient outcome. 2. To determine mechanisms by which a differential HS degradation specificity by heparanases results in inhibition or promotion of brain metastasis. These studies will assert 1) the relevance of heparanases (in particular Hpa-2) in cancer biology, and 2) the importance of HS chains as promoters or inhibitors of melanoma growth and metastasis, specifically to the brain. They will provide a framework for the development of polysaccharide-based anti-cancer molecules as important prognostic tools and diagnostic screens for metastatic detection, diagnosis and treatment.