Visualizing surface marker expression and intratumoral heterogeneity with SERRS-NPs imaging

Abstract

Cell surface marker expression in tumors dictates the selection of therapeutics, therapy response, and survival. However, biopsies are invasive, sample only a small area of the tumor landscape and may miss significant areas of heterogeneous expression. Here, we investigated the potential of antibody-conjugated surface-enhanced resonance Raman scattering nanoparticles (SERRS-NPs) to depict and quantify high and low tumoral surface marker expression, focusing on the surface markers epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) in an intracerebral and peripheral setting with an inter-and intratumoral comparison of Raman signal intensities. Methods: ICR-Prkdc <scid> mice were injected with glioblastoma, epidermoid carcinoma, or breast tumor cell lines intracerebrally and peripherally. SERRS-NPs were functionalized with cetuximab or trastuzumab and administered via tail vein injection. Raman imaging was performed 18 hours post-injection in excised tumors and in vivo through the skull. Tumors were then fixed and processed for immunohistochemical evaluation. Results: Confirmed by MRI and immunohistochemistry for EGFR and HER2, our results demonstrate that antibody-conjugated SERRS-NPs go beyond the delineation of a tumor and offer clear and distinct Raman spectra that reflect the distribution of the targeted surface marker. The intensity of the SERRS-NP signal accurately discriminated high-versus low-expressing surface markers between tumors, and between different areas within tumors. Conclusion: Biopsies can be highly invasive procedures and provide a limited sample of molecular expression within a tumor. Our nanoparticle-based Raman imaging approach offers the potential to provide non-invasive and more comprehensive molecular imaging and an alternative to the current clinical gold standard of immunohistochemistry.

Recent Advances in Enhancement of Raman Scattering Intensity for Biological Applications

“…At the same time, through the combination of SERS and bioorthogonal chemistry, small Raman reporters, such as carbon-deuterium bonds, alkynes, and azides, can be used to image biomolecules such as lipids, proteins, and glycans on the cell surface . Recently, immuno-SERS (iSERS) has achieved rapid and sensitive specific localization imaging of cell surface marker proteins at the single-cell level by coupling surface-enhanced scattering nanoparticles to antibodies. − Compared with the currently used immunofluorescence, which suffers from problems like background fluorescence interference, photobleaching, and fluorescence spectrum overlap, iSERS shows great advantages . Based on the specific recognition of tumor cells by iSERS, the rapid and accurate identification of tumor tissues and normal tissues in clinical practice are expected to be realized, so as to achieve the ultimate goal of intraoperative cancer imaging.…”

Gold Nanoparticles Contact with Cancer Cell: A Brief Update

“…To date, proteins [ 107 ], peptides [ 108 ], aptamer [ 109 ], lectins [ 110 ], carbohydrates [ 111 ], small molecules [ 112 ] and antibodies [ 113 ] have been exploited as targeting ligands. Among antibodies, two clinically approved monoclonal antibodies, cetuximab (anti-EGFR) and trastuzumab (anti-HER-2) were used to functionalize AuNPs for enhanced cancer radiotherapy or to depict and quantify high and low tumoral surface marker expression [ 114 , 115 ]. As the large size of antibodies can potentially inhibit their penetration into tumors, antibody fragments or nano-bodies (smaller than antibody fragments) have recently attracted great attention as viable targeting moieties [ 116 , 117 ].…”

Multimodal Imaging of Pancreatic Cancer Microenvironment in Response to an Antiglycolytic Drug

“…Histochemistry is the conventional method to visually examine the gross tissue morphology, cell type, and subcellular structure through the reaction of certain dyes and stains with endogenous chemicals that are present to form colored compounds. [ 13 ] IHC, however, can only probe one or a small number of biomarkers at once in a sample. [ 14 ] Furthermore, the utilization of many chemical constituents is restricted in traditional histochemistry, thereby constraining its applicability.…”