Xiao Lifu, Harihar Sitaram, Welch Danny R, Zhou Anhong
Department of Biological Engineering, Utah State University, Logan, UT 84322-4105, USA.
Department of Cancer Biology, The University of Kansas Medical Center and The University of Kansas Cancer Center, Kansas City, KS 66160, USA.
Anal Chim Acta. 2014 Sep 16;843:73-82. doi: 10.1016/j.aca.2014.06.036. Epub 2014 Jun 21.
Epidermal growth factor receptor (EGFR) is widely used as a biomarker for pathological grading and therapeutic targeting of human cancers. This study investigates expression, spatial distribution as well as the endocytosis of EGFR in single breast cancer cells using surface-enhanced Raman spectroscopy (SERS). By incubating anti-EGFR antibody conjugated SERS nanoprobes with an EGFR-over-expressing cancer cell line, A431, EGFR localization was measured over time and found to be located primarily at the cell surface. To further validate the constructed SERS probes, we applied this SERS probes to detect the EGFR expression on breast cancer cells (MDA-MB-435, MDA-MB-231) and their counterpart cell lines in which EGFR expression was down-regulated by breast cancer metastasis suppressor 1 (BRMS1). The results showed that SERS method not only confirms immunoblot data measuring EGFR levels, but also adds new insights regarding EGFR localization and internalization in living cells which is impossible in immunoblot method. Thus, SERS provides a powerful new tool to measure biomarkers in living cancer cells.
表皮生长因子受体（EGFR）被广泛用作人类癌症病理分级和治疗靶点的生物标志物。本研究使用表面增强拉曼光谱（SERS）研究了单乳腺癌细胞中EGFR的表达、空间分布以及内吞作用。通过将抗EGFR抗体偶联的SERS纳米探针与EGFR过表达的癌细胞系A431孵育，随着时间的推移测量EGFR的定位，发现其主要位于细胞表面。为了进一步验证构建的SERS探针，我们应用该SERS探针检测乳腺癌细胞（MDA-MB-435、MDA-MB-231）及其对应细胞系中EGFR的表达，在这些对应细胞系中，乳腺癌转移抑制因子1（BRMS1）下调了EGFR的表达。结果表明，SERS方法不仅证实了测量EGFR水平的免疫印迹数据，还提供了有关活细胞中EGFR定位和内化的新见解，而这在免疫印迹方法中是不可能实现的。因此，SERS为测量活癌细胞中的生物标志物提供了一种强大的新工具。
