Sudo Hitomi, Tsuji Atsushi B, Sugyo Aya, Abe Masaaki, Hino Okio, Saga Tsuneo
Diagnostic Imaging Program, Molecular Imaging Center, National Institute of Radiological Sciences, Inage-ku, Chiba 263‑8555, Japan.
Department of Pathology and Oncology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan.
Int J Oncol. 2014 Feb;44(2):530-8. doi: 10.3892/ijo.2013.2183. Epub 2013 Nov 20.
The worldwide incidence of the highly aggressive tumor mesothelioma is expected to increase. Mesothelioma is classified into three main histological subtypes: epithelioid, sarcomatoid and biphasic. Although the pathological diagnostic markers for epithelioid are established, to date no adequate marker for sarcomatoid mesothelioma has been found. Thus, a reliable diagnostic marker of sarcomatoid mesothelioma is necessary. In this study, to identify an unknown protein with 120 kDa expressed only in the mesothelioma cell line 211H, we conducted proteomic analysis and found five candidate proteins. One such protein, AHNAK, was highly expressed in all seven mesothelioma cell lines (211H, H28, H226, H2052, H2452, MESO1 and MESO4), but not in the mesothelial cell line MeT-5A by RT-PCR and immunofluorescence staining. Furthermore, we confirmed high AHNAK expression not only in xenografts but also in human mesothelioma specimens including sarcomatoid, epithelioid and biphasic mesothelioma using immunohistochemical staining. These findings suggest that AHNAK has the potential to be a new marker for detecting mesothelioma. Since AHNAK is involved in cell migration and invasion in other metastatic tumor cells, we conducted migration and invasion assays in mesothelioma cell lines. The number of migrating cells in six of seven mesothelioma cell lines and the number of invading cells in all seven cell lines were significantly increased compared with those in MeT-5A. Knockdown of AHNAK significantly reduced the cell migration and invasion ability in all seven mesothelioma cell lines. These results support further clinical evaluation of the association of AHNAK and metastasis in mesothelioma.
高度侵袭性肿瘤间皮瘤的全球发病率预计将会上升。间皮瘤主要分为三种组织学亚型：上皮样型、肉瘤样型和双向型。尽管上皮样型间皮瘤的病理诊断标志物已经确立，但迄今为止尚未发现用于肉瘤样型间皮瘤的合适标志物。因此，肉瘤样型间皮瘤需要一种可靠的诊断标志物。在本研究中，为了鉴定一种仅在间皮瘤细胞系211H中表达的120 kDa未知蛋白，我们进行了蛋白质组学分析并发现了5种候选蛋白。其中一种名为AHNAK的蛋白，在所有7种间皮瘤细胞系（211H、H28、H226、H2052、H2452、MESO1和MESO4）中均高表达，但通过逆转录聚合酶链反应（RT-PCR）和免疫荧光染色发现其在间皮细胞系MeT-5A中不表达。此外，我们通过免疫组化染色证实，AHNAK不仅在异种移植瘤中高表达，在包括肉瘤样型、上皮样型和双向型间皮瘤的人类间皮瘤标本中也高表达。这些发现表明，AHNAK有可能成为检测间皮瘤的新标志物。由于AHNAK在其他转移性肿瘤细胞中参与细胞迁移和侵袭，我们在间皮瘤细胞系中进行了迁移和侵袭实验。与MeT-5A相比，7种间皮瘤细胞系中的6种细胞系的迁移细胞数量以及所有7种细胞系的侵袭细胞数量均显著增加。敲低AHNAK可显著降低所有7种间皮瘤细胞系的细胞迁移和侵袭能力。这些结果支持进一步对AHNAK与间皮瘤转移之间的关联进行临床评估。
