Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan 250014, China.
Biochem Biophys Res Commun. 2013 Sep 20;439(2):241-6. doi: 10.1016/j.bbrc.2013.08.049. Epub 2013 Aug 22.
In colorectal neoplasms, N-myc downstream-regulated gene 1 (NDRG1) is a primarily cytoplasmic protein, but it is also expressed on the cell membrane and in the nucleus. NDRG1 is involved in various stages of tumor development in colorectal cancer, and it is possible that the different subcellular localizations may determine the function of NDRG1 protein. Here, we attempt to clarify the characteristics of NDRG1 protein subcellular localization during the progression of colorectal cancer. We examined NDRG1 expression in 49 colorectal cancer patients in cancerous, non-cancerous, and corresponding lymph node tissues. Cytoplasmic and membrane NDRG1 expression was higher in the lymph nodes with metastases than in those without metastases (P<0.01). Nuclear NDRG1 expression in colorectal neoplasms was significantly higher than in the normal colorectal mucosa, and yet the normal colorectal mucosa showed no nuclear expression. Furthermore, our results showed higher cytoplasmic NDRG1 expression was better for differentiation, and higher membrane NDRG1 expression resulted in a greater possibility of lymph node metastasis. These data indicate that a certain relationship between the cytoplasmic and membrane expression of NDRG1 in lymph nodes exists with lymph node metastasis. NDRG1 expression may translocate from the membrane of the colorectal cancer cells to the nucleus, where it is involved in lymph node metastasis. Combination analysis of NDRG1 subcellular expression and clinical variables will help predict the incidence of lymph node metastasis.
在结直肠肿瘤中，N- MYC 下游调节基因 1（NDRG1）主要是细胞质蛋白，但也表达在细胞膜和细胞核上。NDRG1 参与结直肠癌肿瘤发展的各个阶段，不同的亚细胞定位可能决定 NDRG1 蛋白的功能。在这里，我们试图阐明结直肠癌进展过程中 NDRG1 蛋白亚细胞定位的特征。我们检测了 49 例结直肠癌患者癌组织、非癌组织和相应淋巴结组织中 NDRG1 的表达。有转移的淋巴结中细胞质和膜 NDRG1 的表达高于无转移的淋巴结（P<0.01）。结直肠肿瘤中的核 NDRG1 表达明显高于正常结直肠黏膜，但正常结直肠黏膜无核表达。此外，我们的结果表明，细胞质 NDRG1 表达越高，分化越好，膜 NDRG1 表达越高，淋巴结转移的可能性越大。这些数据表明，淋巴结中 NDRG1 的细胞质和膜表达之间存在一定的关系，与淋巴结转移有关。NDRG1 表达可能从结直肠癌细胞的膜转位到细胞核，参与淋巴结转移。NDRG1 亚细胞表达与临床变量的联合分析有助于预测淋巴结转移的发生。
