DIFFERENT FORMS OF PROSTATE-SPECIFIC ANTIGEN IN CANCER

前列腺癌是美国男性的一种主要癌症形式。前列腺 血清特异性抗原(PSA)水平是前列腺癌的良好标志物 癌症，但单靠血清总PSA检测不能区分早期 其他一些前列腺疾病导致的癌症。无数的侵入性和 诊断可能需要昂贵的程序。初步结果 表明PSA以不同的形式存在于精液和 且在不同患者血清中发现不同的PSA形式 病人。这项提案要求提供资金，以建立一个新的独立 申请人的研究领域，其中各种形式的PSA将 在大量临界性患者中进行鉴定、检测 总PSA升高，并与诊断相关。长期的 目的是为临床提供生化和免疫化学依据。 前列腺癌早期与其他前列腺癌的不同PSA检测 导致PSA适度升高的情况。它是假设的：a) PSA作为一种酶在前列腺癌中的作用可能与在前列腺癌中不同 良性前列腺或前列腺炎；b)PSA酶 以不活跃的酵素形式分泌，在特定条件下被激活 病理生理条件，并通过蛋白水解酶或 通过与现有的蛋白酶抑制剂结合形成复合体；c) 当地的环境和分泌的上皮细胞的类型 前列腺癌的PSA与其他综合征不同；d)前列腺癌 PSA接触的激活剂、蛋白水解酶和抑制剂 癌症与其他症状不同；e)时间流逝 PSA的分泌和转运到血液中的区别在于 癌症与其他症状的关系；f)酶和 前列腺液中的抑制剂与血液中的不同；以及 以上所有这些都导致了不同形式的PSA在 前列腺癌与其他综合征的前列腺癌不同。申请人的 以往在阐明血管紧张素转换酶的分子形式和抑制剂方面的经验 其他酶可以很容易地应用于鉴定和 患者不同形态前列腺特异性抗原的检测。具体目标 包括：1)精液中PSA的分离、鉴定 多种蛋白水解酶抑制剂的反应性及标准品的制备 PSA-抑制物复合体；2)PSA双抗体夹心ELISA检测方法的建立 与任何重要抑制剂的复合体，包括 α1-抗糜蛋白酶、蛋白C抑制物、α2-巨球蛋白和 可使用标准复合体识别的其他；3) 不同形态PSA在精液和血液中的鉴定 免疫印迹分析和测序研究；4)抗体的研制 以及针对特定形式或序列的PSA的酶联免疫吸附试验；5) 免疫印迹分析、夹心ELISA等检测方法的应用 它被发展成大量的患者血清，特别是那些 临界PSA范围；以及6)光谱和能级的相关性 以不同的PSA形式对患者进行诊断，建立临床 化验结果的有用性。拟议的研究还提供了新的基础 关于PSA及其抑制剂的知识可能有助于理解 这种酶的生理功能和调节。

Prostate cancer is a major form of cancer in U.S. males. Prostate specific antigen (PSA) serum levels provide a good marker for prostate cancer, but assay of total serum PSA alone cannot distinguish early cancer from a number of other prostatic diseases. Numerous invasive and expensive procedures may be required for diagnosis. Preliminary results of the applicant indicate that PSA exists in different forms in semen and in serum and that different PSA forms are found in the sera of different patients. This proposal requests funding to establish a new independent research area for the applicant, in which the various forms of PSA will be identified, assayed in a large number of patients with borderline elevations of total PSA, and correlated to the diagnosis. The long-term goal is to provide the biochemical and immunochemical basis for clinical assays of forms of PSA that distinguish early prostate cancer from other conditions that cause modestly elevated PSA. It is hypothesized: a) that PSA as an enzyme may have a different role in prostate cancer than in benign conditions of the prostate or prostatitis; b) that the enzyme PSA is secreted in inactive zymogen form, activated under particular pathophysiological conditions, and inactivated by proteolytic cleavage or by combining with available protease inhibitors to form complexes; c) that the local environment and the type of epithelial cells that secrete PSA differ in prostate cancer compared to other syndromes; d) that the activators, proteolytic enzymes and inhibitors to which PSA is exposed differ in cancer compared to other syndromes; e) that the time elapsed between secretion of PSA and its translocation to the blood differs in cancer versus other syndromes; f) that the spectrum of enzymes and inhibitors in prostatic fluid is different from that of blood; and g) that all of the above lead to the generation of different forms of PSA in prostate cancer from those found in other syndromes. The applicant's previous experience in elucidating the molecular forms and inhibitors of other enzymes can be readily applied to the identification and measurement of different forms of PSA in patients. The specific aims include: 1) isolation of PSA from semen, characterization of its reactivity with various protease inhibitors, and preparation of standard PSA-inhibitor complexes; 2) development of sandwich ELISA assays for PSA complexes with any significant inhibitors, including alpha1-antichymotrypsin, protein C inhibitor, alpha2-macroglobulin, and others that may be identified, using standard complexes; 3) identification of different forms of PSA in semen and in blood by immunoblot analysis and sequencing studies; 4) development of antibodies and ELISA-assays specific for particular forms or sequences of PSA; 5) application of immunoblot analysis, sandwich ELISAS and other assays which are developed to large numbers of patient sera, especially those in the borderline PSA range; and 6) correlation of the spectrum and levels of different PSA forms to patient diagnosis to establish clinical usefulness of the assays. The proposed studies also provide novel basic knowledge about PSA and its inhibitors that may help to understand the physiological function and regulation of this enzyme.