Using aptamers to elucidate esophageal cancer clinical samples.

Zhenxu Liu,Yi Lu,Jun Liu,Chaoyong James Yang,Ying Pu,Bo Yu,Bo Liu,Ke Chen,Huixia Liu,Ting Fu,Weihong Tan

doi:10.1038/srep18516

Abstract

The epithelial cell adhesion molecule (EpCAM) is closely correlated with the occurrence and development of various cancers of epithelial origin. This study tested, for the first time, the ability of EpCAM aptamer SYL3C to detect EpCAM expression in 170 cases of esophageal cancer (EC) and precancerous lesions, as well as 20 cases of EC series samples, using immunofluorescence imaging analysis. Corresponding antibodies were used as control. EpCAM overexpression was 98% in both esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EACA) and 100% in metastasis, but no EpCAM overexpression was detected in undifferentiated EC (UEC). Significant differences were noted among various stages of differentiation (p < 0.05) with the degree of differentiation inversely correlated with the expression of EpCAM. Overexpressed EpCAM was detected in severe dysplasia, but negative in mild to moderate dysplasia and benign esophageal lesions. In a competitive binding experiment, EpCAM aptamer generated a staining pattern similar to that of antibody, but the binding sites with EpCAM were different. Based on these results, it can be concluded that EpCAM is suitable for use as an EC biomarker, therapeutic target, and effective parameter for tumor transfer and prognosis evaluation by aptamer SYL3C staining.

Highlights

The present project was designed to test the feasibility of aptamer SYL3C as a molecular diagnostic/ prognostic tool by evaluating its binding ability in the detection of EpCAM expression based on 170 cases of Esophageal cancer (EC) and precancerous lesions, as well as 20 cases of EC series samples, using immunofluorescence imaging analysis
All 20 cases of normal esophageal epithelium from the same patient with EC showed negative EpCAM expression by specific staining with aptamer SYL3C probe. Sixty cases each, both esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EACA), showed 98% overexpression of EpCAM by SYL3C, while all 20 cases of metastasis appeared as 100% overexpressed
When the same tissue types (ESCC or EACA) showing different degrees of differentiation were compared with EpCAM staining by SYL3C probe, a significant difference among the various differentiation stages could be observed, such that a decreasing degree of differentiation correlated with increasing expression of EpCAM among ESCC or EACA (Fig. 1A,B)

Summary

Introduction

All 20 cases of normal esophageal epithelium from the same patient with EC showed negative EpCAM expression by specific staining with aptamer SYL3C probe. Ten cancer nests stained with aptamer SYL3C for both frozen tissue section and paraffin-embedded tissue sections showed similar results (Supplementary Fig. S1). When the same tissue types (ESCC or EACA) showing different degrees of differentiation were compared with EpCAM staining by SYL3C probe, a significant difference among the various differentiation stages could be observed, such that a decreasing degree of differentiation correlated with increasing expression of EpCAM among ESCC or EACA (Fig. 1A,B).

Results

Conclusion