Bioimaging Nucleic-Acid Aptamers with Different Specificities in Human Glioblastoma Tissues Highlights Tumoral Heterogeneity

Abstract

Nucleic-acid aptamers are of strong interest for diagnosis and therapy. Compared with antibodies, they are smaller, stable upon variations in temperature, easy to modify, and have higher tissue-penetration abilities. However, they have been little described as detection probes in histology studies of human tissue sections. In this study, we performed fluorescence imaging with two aptamers targeting cell-surface receptors EGFR and integrin α5β1, both involved in the aggressiveness of glioblastoma. The aptamers’ cell-binding specificities were confirmed using confocal imaging. The affinities of aptamers for glioblastoma cells expressing these receptors were in the 100–300 nM range. The two aptamers were then used to detect EGFR and integrin α5β1 in human glioblastoma tissues and compared with antibody labeling. Our aptafluorescence assays proved to be able to very easily reveal, in a one-step process, not only inter-tumoral glioblastoma heterogeneity (differences observed at the population level) but also intra-tumoral heterogeneity (differences among cells within individual tumors) when aptamers with different specificities were used simultaneously in multiplexing labeling experiments. The discussion also addresses the strengths and limitations of nucleic-acid aptamers for biomarker detection in histology.

Biotinylated Fluorescent Polymeric Nanoparticles for Enhanced Immunostaining

“…The remaining question was whether our method of receptor detection using PEMA-ZI-biotin-NPs can differentiate cancerrelevant cell lines according to their EGFR expression level: high EGFR expressing U87 cells, and EGFR-negative LN319 and MCF-7 cells. [80,81] To this end, the cells were incubated with biotinylated cetuximab, followed by fixation and then addition of streptavidin and finally biotinylated NPs (Figure 7a and Figure S4, Supporting Information). For comparison, analogous staining was done using Cy3-labeled streptavidin.…”

Aptamer-Based Recognition of Breast Tumor Cells: A New Era for Breast Cancer Diagnosis

“…Thus, aptamers are presented as biosensors for bio-recognition with possible application for molecular diagnosis [13,14]. Some groups are already studying the application of multiplex aptamer-histofluorescence using more than one aptamer as a molecular probe to characterize the profile of heterogeneity in glioblastoma [15]. In the present study, we propose the identification of tumor-specific aptamers that can be used as a diagnostic and prognostic tool for breast cancer.…”