Wang Wei, de Nier Carmen R, Wuhrer Manfred, Lageveen-Kammeijer Guinevere S M
Leiden University Medical Center, Center for Proteomics and Metabolomics, Leiden 2300 RC, The Netherlands.
University of Groningen, Groningen Research Institute of Pharmacy, Groningen 9713 AV, The Netherlands.
ACS Meas Sci Au. 2023 Dec 8;4(1):117-126. doi: 10.1021/acsmeasuresciau.3c00055. eCollection 2024 Feb 21.
Prostate-specific antigen (PSA) is a well-known clinical biomarker in prostate cancer (PCa) diagnosis, but a better test is still needed, as the serum-level-based PSA quantification exhibits limited specificity and comes with poor predictive value. Prior to PSA, prostatic acid phosphatase (PAP) was used, but it was replaced by PSA because PSA improved the early detection of PCa. Upon revisiting PAP and its glycosylation specifically, it appears to be a promising new biomarker candidate. Namely, previous studies have indicated that PAP glycoforms differ between PCa and non-PCa individuals. However, an in-depth characterization of PAP glycosylation is still lacking. In this study, we established an in-depth glycoproteomic assay for urinary PAP by characterizing both the micro- and macroheterogeneity of the PAP glycoprofile. For this purpose, PAP samples were analyzed by capillary electrophoresis coupled to mass spectrometry after affinity purification from urine and proteolytic digestion. The developed urinary PAP assay was applied on a pooled DRE (digital rectal examination) urine sample from nine individuals. Three glycosylation sites were characterized, namely N, N, and N, via -glycopeptide analysis. Taking sialic acid linkage isomers into account, a total of 63, 27, and 4 -glycan structures were identified, respectively. The presented PAP glycoproteomic assay will enable the determination of potential glycomic biomarkers for the early detection and prognosis of PCa in cohort studies.
前列腺特异性抗原（PSA）是前列腺癌（PCa）诊断中一种广为人知的临床生物标志物，但仍需要一种更好的检测方法，因为基于血清水平的PSA定量检测特异性有限且预测价值不佳。在PSA出现之前，人们使用前列腺酸性磷酸酶（PAP），但它被PSA取代了，因为PSA提高了PCa的早期检测率。当专门重新审视PAP及其糖基化时，它似乎是一个有前景的新型生物标志物候选物。也就是说，先前的研究表明PCa个体和非PCa个体之间的PAP糖型存在差异。然而，对PAP糖基化的深入表征仍然缺乏。在本研究中，我们通过表征PAP糖蛋白谱的微观和宏观异质性，建立了一种用于尿液PAP的深入糖蛋白质组学分析方法。为此，从尿液中亲和纯化并进行蛋白水解消化后，通过毛细管电泳与质谱联用对PAP样品进行分析。所开发的尿液PAP分析方法应用于来自9名个体的混合直肠指检（DRE）尿液样本。通过 -糖肽分析确定了三个糖基化位点，即N、N和N。考虑到唾液酸连接异构体，分别鉴定出总共63、27和4种 -聚糖结构。所提出的PAP糖蛋白质组学分析方法将能够在队列研究中确定用于PCa早期检测和预后的潜在糖组学生物标志物。
