Pu Ying, Liu Zhenxu, Lu Yi, Yuan Peng, Liu Jun, Yu Bo, Wang Guodong, Yang Chaoyong James, Liu Huixia, Tan Weihong
Xiangya Hospital, Central South University , Changsha, Hunan 410008, China.
Anal Chem. 2015 Feb 3;87(3):1919-24. doi: 10.1021/ac504175h. Epub 2015 Jan 16.
Tissue immunostaining is critically important in clinical applications, and antibodies have been used extensively as the molecular probes. Recently, aptamer, as a new class of probes, have attracted much attention for their potential clinical and research value. Epithelial cell adhesion molecule (EpCAM) is a specific biomarker which is overexpressed in many cancers of epithelial origin. Here, a DNA-based EpCAM aptamer SYL3C is reported as a probe for the immunostaining of frozen and paraffin-embedded sections of colorectal cancer tissues. Commercialized EpCAM antibodies were also used as a standard control. EpCAM aptamer SYL3C specifically recognized and immunostained cancer nests of colorectal tumor sections, but it neither reacted with background cells within tumor sites nor exhibited cross-reaction to the benign lesions or inflammation of colorectal tissues. No cross-linking to EpCAM-negative malignant tumor sections occurred. Compared with standard antibody staining, our EpCAM aptamer SYL3C protocol is simpler to implement with a shorter reaction time. Moreover, SYL3C can specifically bind with either frozen or paraffin-embedded tissue sections. Since the histopathology of frozen tissue is closer to that of fresh tissue and since frozen sections can be produced more quickly than paraffin-embedded sections, SYL3C immunostaining of frozen sections is a quick protocol that is easy to implement.
组织免疫染色在临床应用中至关重要，抗体已被广泛用作分子探针。最近，适体作为一类新型探针，因其潜在的临床和研究价值而备受关注。上皮细胞粘附分子（EpCAM）是一种特异性生物标志物，在许多上皮源性癌症中过表达。在此，报道了一种基于DNA的EpCAM适体SYL3C作为结直肠癌组织冰冻切片和石蜡包埋切片免疫染色的探针。商业化的EpCAM抗体也用作标准对照。EpCAM适体SYL3C能特异性识别并免疫染色结直肠癌肿瘤切片中的癌巢，但它既不与肿瘤部位的背景细胞发生反应，也不对结直肠组织的良性病变或炎症产生交叉反应。未发生与EpCAM阴性恶性肿瘤切片的交联。与标准抗体染色相比，我们的EpCAM适体SYL3C方案实施更简单，反应时间更短。此外，SYL3C能与冰冻或石蜡包埋的组织切片特异性结合。由于冰冻组织的组织病理学更接近新鲜组织，且冰冻切片的制作速度比石蜡包埋切片更快，因此冰冻切片的SYL3C免疫染色是一种易于实施的快速方案。
