Xu Xiuping, Yan Qiuyue, Wang Yanan, Dong Xuejun
Shaoxing People's Hospital, Shaoxing Hospital Zhejiang University, Shaoxing, Zhejiang, P.R. China.
Oncol Rep. 2017 Jan;37(1):449-457. doi: 10.3892/or.2016.5239. Epub 2016 Nov 9.
Metastasis is the leading cause of death for breast cancer patients. Nerve guidance factor 4 (Netrin-4, NTN4) is reduced in variety of malignancies and involved in tumor metastasis. However, the functions of NTN4 and related molecular mechanisms in breast cancer are poorly understood. Oncomine data revealed that NTN4 was decreased in breast cancer compared with normal breast tissues. For fresh frozen breast cancer samples, significantly depressed expression of NTN4 mRNA was observed in lesion tissues compared with that in adjacent tissues. Afterwards, NTN4 protein level was evaluated in 52 paired breast cancer tissues, and the results were consistent with that in fresh frozen samples. NTN4 expression was upregulated using NTN4-pcDNA3.1 plasmid in MDA-MB-231 cells and silenced using NTN4 small interfering RNA (siRNA) in Hs578T cells. Then the effects of NTN4 overexpression or knockdown on breast cancer cell migration and invasion were investigated. The results manifested that NTN4 overexpression attenuated cell migration and invasion, and induced N-cadherin and vimentin downregulation, while NTN4 siRNA-transfected cells had a significant increase in migration and invasion, as well as upregulation in N-cadherin and vimentin expression. These results demonstrate that NTN4 is reduced in breast cancer tissues and NTN4 is associated with breast cancer cell migration and invasion via regulation of epithelial mesenchymal transition (EMT)-related biomarkers.
转移是乳腺癌患者的主要死因。神经导向因子4（Netrin-4，NTN4）在多种恶性肿瘤中表达降低，并参与肿瘤转移。然而，NTN4在乳腺癌中的功能及相关分子机制尚不清楚。Oncomine数据显示，与正常乳腺组织相比，NTN4在乳腺癌中表达降低。对于新鲜冷冻的乳腺癌样本，与相邻组织相比，病变组织中NTN4 mRNA表达明显降低。随后，在52对乳腺癌组织中评估NTN4蛋白水平，结果与新鲜冷冻样本一致。在MDA-MB-231细胞中使用NTN4-pcDNA3.1质粒上调NTN4表达，在Hs578T细胞中使用NTN4小干扰RNA（siRNA）沉默NTN4表达。然后研究NTN4过表达或敲低对乳腺癌细胞迁移和侵袭的影响。结果表明，NTN4过表达减弱细胞迁移和侵袭，并诱导N-钙黏蛋白和波形蛋白下调，而转染NTN4 siRNA的细胞迁移和侵袭显著增加，同时N-钙黏蛋白和波形蛋白表达上调。这些结果表明，NTN4在乳腺癌组织中表达降低，且NTN4通过调节上皮-间质转化（EMT）相关生物标志物与乳腺癌细胞迁移和侵袭相关。
