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

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，由于其低特异性和缺乏相关性的侵略性，新的生物标志物，以补充PSA是肯定需要的。我们之前报道了Nardilysin（NRDc）促进各种生长因子和细胞因子前体形式的胞外域脱落，如肝素结合表皮生长因子样生长因子（HB-EGF）和肿瘤坏死因子-α（TNFα）（Nishi et al，2006）。本研究的目的是评估NRDc与PC侵袭性的相关性及其作为预后标志物的潜力。B）方法通过实时PCR和Western印迹分析LNCaP和PC 3细胞中NRDc的表达水平。为了评估与细胞侵袭性的关联，在PC 3中敲低NRDc，并在这些细胞中进行体外基质胶侵袭测定和体内异种移植肿瘤生长测定。结果NRDc在PC 3中的表达水平高于LNCaP。NRDc敲低抑制体外细胞侵袭和体内细胞增殖。在IHC分析中，NRDc表达水平倾向于与手术治疗后的生化复发呈正相关（p=0.30）。PC患者血清NRDc浓度（652 pg/ml±1950，n=161）显著高于正常对照组（303 pg/ml±510，n=20）（p=0.0269），尤其是转移性PC患者，并与患者预后相关。PC患者血清NRDc水平与血清PSA水平无相关性。NRDc与PC的侵袭性相关，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.