RIBONUCLEASES IN CANCER CHEMOTHERAPY

描述(摘自申请者摘要)：建议的总体目标 研究旨在揭示核糖核酸酶A(RNaseA)的同源物和变异体如何 促进肿瘤细胞死亡。Onconase，它是RNaseA的两栖同源物， 目前正在进行第三阶段的人体临床试验，用于治疗 恶性间皮瘤与转移瘤治疗的I/II期试验 肾癌。与肿瘤酶不同，核糖核酸酶A没有细胞毒性。在 在最初的资助期间，RNaseA的变体被创建，就像onconase一样， 能够避开内源性核糖核酸酶抑制蛋白(RI) 存在于哺乳动物细胞的胞浆中。这些变种对肿瘤有毒性。 细胞。这一发现预示着一种新的癌症的发展。 基于核糖核酸酶A的同系物和变异体的化疗药物 拟议研究的具体目标是：(1)确定核糖核酸酶A如何 同系物结合到细胞表面，(2)发现RNaseA所走的路线 与胞质RNA同源，(3)揭示关于 RI的亚细胞定位和细胞内功能，以及(4)创建一个 核糖核酸酶A的人类同源物，它对肿瘤细胞的毒性比Onconase更大。 核糖核酸酶A同系物和变异体的相关性质将在 与肿瘤酶(阳性对照)和野生型核糖核酸酶A(阴性)的比较 控制)。这些特性包括细胞毒性、RI逃避、核糖核溶解 活性和构象稳定性。最后，三维 具有显著细胞毒性的RNaseA同系物和变异体的结构将是 经X-射线衍射分析确定。 拟议的研究旨在揭示以下基础的新见解 核糖核酸酶的细胞毒性，并可能导致新的癌症化疗药物。

DESCRIPTION (from applicant's abstract): The overall goal of the proposed research is to reveal how homologs and variants of ribonuclease A (RNase A) promote tumor cell death. Onconase, which is an amphibian homolog of RNase A, is now undergoing Phase III human clinical trials for the treatment of malignant mesothelioma and Phase I/II trials for the treatment of metastatic renal carcinoma. In contrast to onconase, RNase A is not cytotoxic. In the initial funding period, variants of RNase A were created that, like onconase, were able to evade the endogenous ribonuclease inhibitor protein (RI) that resides in the cytosol of mammalian cells. These variants were toxic to tumor cells. This finding portends the development of a new class of cancer chemotherapeutics based on homologs and variants of RNase A. The specific aims of the proposed research are: (1) to determine how RNase A homologs bind to the cell surface, (2) to discover the route taken by RNase A homologs to cytosolic RNA, (3) to reveal fundamental information about the subcellular localization and intracellular function of RI, and (4) to create a human homolog of RNase A that is more toxic to tumor cells than onconase. Relevant properties of RNase A homologs and variants will be assessed in comparison to onconase (positive control) and wild-type RNase A (negative control). These properties include cytotoxicity, RI evasion, ribonucleolytic activity, and conformational stability. Finally, the three-dimensional structures of RNase A homologs and variants with notable cytotoxicity will be determined by X-ray diffraction analysis. The proposed research is designed to reveal new insights into the basis of ribonuclease cytotoxicity, and could lead to new cancer chemotherapeutics.