前列腺增生和前列腺癌患者血、尿中PSA糖链结构的改变及意义

Structural alterations and significance of sugar chains of PSA in urine and blood from BPH and PCa patients

目的探索前列腺癌的早期诊断和鉴别诊断的新依据。方法收集前列腺增生和前列腺癌患者空腹第一次晨尿和血标本各90份和30份,随机分为3组,用PSA抗体亲和层析柱提纯尿液和血液中的PSA,用辣根过氧化物酶(HRP)标记的凝集素SNA(sambucus nigra agglutinin)做探针,连接到已固定在膜上纯化的PSA的糖链,检测已结合的HRP来代表PSA糖链与凝集素的结合力,用增强化学发光法(ECL)检测已结合的HRP的结合力,其数值用发光单位(LLU)来表示。结果用HRP标记的凝集素SNA-HRP作探针检测前列腺癌和前列腺增生血中PSA时,前列腺癌血中平均LLU仅为前列腺增生血中PSA的18.3%,与SNA-HRP的结合力两者之间有明显差异(P<0.001);而在尿液中两者无明显差异(P>0.05)。说明前列腺癌血中PSA糖链结构中唾液酸残基表达较前列腺增生明显减少。结论前列腺癌患者血中PSA糖链结构与前列腺增生相比发生改变,其中糖链结构中唾液酸残基表达的改变可能为今后前列腺癌的早期诊断和鉴别诊断提供新的依据。

Objectives To find out a new potential biomarkers for the early diagnosis and differential diagnosis of the prostatic carcinoma. Methods The morning fasting blood and first time morning urine were respectively collected from subjects with PCa and BPH before initiation of any treatment. Three pairs of urine samples and blood samples were from three groups of PCa patients and BPH patients respectively. Each BPH group contained thirty persons＇ blood and urine respectively and each PCa group contained ten persons＇ blood and urine respectively. The PSA in the urine and blood samples was purified with an anti-PSA antibody affinity column. The lectin sambucus nigra agglutinin （SNA） labeled with horseradish peroxidase （HRP） was used as probes to bind the glycans of purified PSA immobilized on membrane. Enhanced chemiluminescence （ECL） reagent was adopted to estimate the activity of the bound HRP as a measure of the binding affinity of the PSA glycans to lectins, and expressed as luminescent light units（LLU）. Results The mean LLU of blood PSA of PCa was only 18.3% of the BPH blood samples. There was significantly difference between them（P〈0.001）. The mean LLU of urine PSA between PCa and BPH samples of the urine was almost the same when SNA were used as probes. There was no significantl difference between them（P〉0.05）. Condusion The alteration of the lectin residues of PSA between BPH and PCa blood PSA may be of clinical importance in the evaluation of prostate health, especially when SNA was used.