Exploration for a novel biomarker and a new therapeutic target of castration resistant prostate cancer in terms of cancer microenvironment

前言与目的前列腺特异性抗原(PSA)是前列腺癌(PC)的诊断或治疗生物标志物。然而，由于其特异性低，与侵袭性缺乏相关性，因此肯定需要新的生物标志物来补充PSA。我们以前报道过，纳迪赖素促进各种生长因子和细胞因子的前体形式的胞外脱落，如肝素结合的表皮生长因子样生长因子和肿瘤坏死因子α(肿瘤坏死因子α)(Nishi et al，2006)。本研究的目的是评价NRDC与PC侵袭性的关系及其作为预后标志物的可能性。b)采用实时荧光定量聚合酶链式反应和Western blotting分析NRDC在LNCaP和PC3细胞中的表达水平。通过体外Matrigel侵袭实验和体内移植瘤生长实验，研究NRDC与PC3细胞侵袭力的关系。采用免疫组织化学(IHC)法检测PC组织中NRDC的表达水平，采用酶联免疫吸附试验(EL ISA)检测PC患者血清中NRDC的浓度。NRDC基因敲除可抑制体外细胞侵袭和体内细胞增殖。在IHC分析中，NRDC的表达水平与术后生化复发呈正相关(p=0.30)。PC患者血清NRDC浓度(652pg/ml±1950，n=161)明显高于正常对照组(303pg/ml±510，n=20)(P=0.0269)，转移性PC患者血清NRDC浓度与患者预后有关。PC患者血清NRDC水平与血清PSA水平无相关性。NRDC与PC侵袭性相关，是预测PC预后的潜在组织和血清标志物。

a)Introduction and ObjectiveProstate specific antigen (PSA) is a diagnostic or therapeutic biomarker for prostate cancer (PC). However, due to its low specificity and lack of relevance with aggressiveness, novel biomarkers to complement PSA are definitely needed. We previously reported that Nardilysin (NRDc) promotes ectodomain shedding of the precursor forms of various growth factors and cytokines, such as heparin-binding epidermal growth factor-like growth factor (HB-EGF) and tumor necrosis factor-α (TNFα) (Nishi et al, 2006). The aim of our study is to evaluate the association of NRDc with PC aggressiveness and its potential to be a prognostic marker.b)Methods NRDc expression levels in LNCaP and PC3 cells were analyzed by real-time PCR and Western blotting. To evaluate the association with cell invasiveness, NRDc was knocked-down in PC3, and in vitro Matrigel invasion assays and in vivo xenograft tumor growth assays were performed in these cells. Then, NRDc expression levels in PC tissues were evaluated by immunohistochemistry (IHC), and NRDc serum concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in serum samples obtained from PC patients.c) Results The expression levels of NRDc were higher in PC3 than in LNCaP. NRDc knocking-down suppressed in vitro cell invasion and in vivo cell proliferation. In IHC analysis the NRDc expression levels tended to be positively correlated with biochemical reccurence after surgical treatment (p=0.30). Serum NRDc concentrations in PC patients (652 pg/ml±1950, n=161) were significantly higher than in normal controls (303 pg/ml±510, n=20) (p=0.0269), especially in metastatic PC patients, and tended to be correlated with patients prognosis. The serum NRDc levels were not correlated with serum PSA levels in PC patients.d) Conclusions. NRDc was associated with PC aggressiveness, being potential tissue and serum markers for predicting PC prognosis.