Key Laboratory for Translational Medicine and the Division of Breast Surgery, The First Affiliated Hospital of Huzhou University School of Medicine, Huzhou, 313000, Zhejiang, China.
Department of Medicine and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA.
Clin Transl Oncol. 2019 Apr;21(4):433-442. doi: 10.1007/s12094-018-1941-1. Epub 2018 Sep 14.
EpCAM is a common marker used in the detection of circulating tumor cells (CTC). Disseminated cancer cells display the characteristics of epithelial-to-mesenchymal transition events. The purpose of this study was to assess the potential of epithelial membrane protein 2 (EMP2) as a novel biomarker for CTC retrieval in breast cancer.
MCF7 and MDA-MB-231 cells were stained with either anti-EpCAM or anti-EMP2 mAbs, respectively, followed by flow cytometric assay to measure their expression levels. PBMCs isolated from healthy donors were used for breast cancer cell spiking. CD45-depleted PBMCs from breast cancer patients' blood were used for CTC capturing. Immunomagnetic separation was used to enrich breast cancer cells. Cytospin centrifugation was performed to concentrate the captured cells, followed by immunofluorescence staining with anti-CD45 mAb, anti-pan cytokeratin mAb and DAPI. Fluorescent images were taken using a confocal microscope for CTC counts.
MDA-MB-231 cells had 2.56 times higher EMP2 expression than MCF7 cells, and EMP2 had a significantly higher capture efficiency than EpCAM for MCF7 cells. Furthermore, anti-EMP2 was capable of capturing MCF7 cells that escaped in the flow-through of anti-EpCAM. Likewise, EMP2 had a significantly higher capture efficiency on MDA-MB-231 cells when compared to MCF7 cells. Most importantly, EMP2 biomarker was successfully used for CTC capture in patients with primary breast cancer.
EMP2 is superior to EpCAM for capturing both MCF7 and MDA-MB-231 cells. Additionally, EMP2 is a novel biomarker and capable of capturing breast cancer cells in patient blood samples.
EpCAM 是一种常用于检测循环肿瘤细胞（CTC）的常见标志物。播散的癌细胞表现出上皮-间充质转化事件的特征。本研究旨在评估上皮膜蛋白 2（EMP2）作为一种新型生物标志物用于乳腺癌 CTC 检测的潜力。
MCF7 和 MDA-MB-231 细胞分别用抗 EpCAM 或抗 EMP2 mAb 染色，然后进行流式细胞术检测其表达水平。从健康供者中分离的 PBMC 用于乳腺癌细胞掺入。从乳腺癌患者血液中分离 CD45 耗尽的 PBMC 用于 CTC 捕获。免疫磁珠分离用于富集乳腺癌细胞。离心涂片法浓缩捕获的细胞，然后用抗 CD45 mAb、抗泛细胞角蛋白 mAb 和 DAPI 进行免疫荧光染色。使用共聚焦显微镜拍摄荧光图像以计数 CTC。
MDA-MB-231 细胞的 EMP2 表达水平比 MCF7 细胞高 2.56 倍，并且 EMP2 对 MCF7 细胞的捕获效率明显高于 EpCAM。此外，抗 EMP2 能够捕获抗 EpCAM 漏过的 MCF7 细胞。同样，与 MCF7 细胞相比，EMP2 对 MDA-MB-231 细胞的捕获效率明显更高。最重要的是，EMP2 标志物成功用于原发性乳腺癌患者的 CTC 捕获。
EMP2 优于 EpCAM 用于捕获 MCF7 和 MDA-MB-231 细胞。此外，EMP2 是一种新型生物标志物，能够捕获患者血液样本中的乳腺癌细胞。
