Hosoya Noriyuki, Sakumoto Marimu, Nakamura Yukiko, Narisawa Takafumi, Bilim Vladimir, Motoyama Teiichi, Tomita Yoshihiko, Kondo Tadashi
Division of Pharmacoproteomics, National Cancer Center Research Institute, Tokyo, Japan; Department of Urology, Yamagata University Faculty of Medicine, Yamagata, Japan.
Biochim Biophys Acta. 2013 Dec;1834(12):2630-9. doi: 10.1016/j.bbapap.2013.08.009. Epub 2013 Aug 30.
The aim of this study was to identify proteins with aberrant expression in clear cell renal cell carcinoma (ccRCC), and elucidate their clinical utilities. The protein expression profiles of primary ccRCC tumor tissues and neighboring non-tumor tissues were obtained from 9 patients by two-dimensional difference gel electrophoresis and mass spectrometry. Comparative analysis of 3771 protein spots led to the identification of 73 proteins that were expressed at aberrant levels in tumor tissues compared with non-tumor tissues. Among these 73 proteins, we further focused on N-myc downstream-regulated gene 1 protein (NDRG1). NDRG1 expression is regulated by members of myc family as well as by p53, HIF1A, and SGK1. The biological and clinical significance of NDRG1 is controversial for various malignancies and no detailed studies on NDRG1 have been reported in ccRCC until our study. For the 82 newly enrolled ccRCC patients, immunohistochemical analysis revealed a significant association between nuclear NDRG1 and favorable prognosis (p<0.05). Multivariate analysis demonstrated the role of NDRG1 as an independent factor of progression-free survival (p=0.01). Subsequent in vitro gene suppression assay demonstrated that NDRG1 silencing significantly enhanced cell proliferation and invasion of RCC cells. The cytotoxic effects of NDRG1 up-regulation induced by an iron chelator were also confirmed. These findings suggest that nuclear NDRG1 has tumor suppressive effects, and the NDRG1 expression may have clinical values in ccRCC. Nuclear NDRG1 may provide additional insights on molecular backgrounds of ccRCC progression, and contribute to the development of novel therapeutic strategy.
本研究旨在鉴定在透明细胞肾细胞癌（ccRCC）中表达异常的蛋白质，并阐明其临床应用价值。通过二维差异凝胶电泳和质谱分析法，从9例患者的原发性ccRCC肿瘤组织和邻近的非肿瘤组织中获取了蛋白质表达谱。对3771个蛋白质斑点进行比较分析，结果鉴定出73种在肿瘤组织中与非肿瘤组织相比表达水平异常的蛋白质。在这73种蛋白质中，我们进一步聚焦于N-myc下游调控基因1蛋白（NDRG1）。NDRG1的表达受myc家族成员以及p53、HIF1A和SGK1的调控。NDRG1在各种恶性肿瘤中的生物学和临床意义存在争议，在我们的研究之前，尚未有关于ccRCC中NDRG1的详细研究报道。对于82例新入组的ccRCC患者，免疫组化分析显示核NDRG1与良好预后之间存在显著关联（p<0.05）。多变量分析表明NDRG1是无进展生存期的独立影响因素（p=0.01）。随后的体外基因抑制试验表明，NDRG1沉默显著增强了肾癌细胞的增殖和侵袭能力。铁螯合剂诱导的NDRG1上调的细胞毒性作用也得到了证实。这些发现表明核NDRG1具有肿瘤抑制作用，NDRG1的表达可能在ccRCC中具有临床价值。核NDRG1可能为ccRCC进展的分子背景提供更多见解，并有助于开发新的治疗策略。
