Targeting CD44v6 for fluorescence-guided surgery in head and neck squamous cell carcinoma

Julia Odenthal,Julia Odenthal,Julia Odenthal,Desirée Bos,Desirée Bos,Otto Boerman,Otto Boerman,Mark Rijpkema,Mark Rijpkema,Huib Croes,Esther Wagena,Esther Wagena,Esther Wagena,Reidar Grenman,Peter Friedl,Peter Friedl,Peter Friedl,Peter Friedl,Robert Takes,Robert Takes

doi:10.1038/s41598-018-28059-9

Abstract

Head and neck squamous cell carcinoma (HNSCC) is an often highly invasive tumor, infiltrating functionally important tissue areas. Achieving complete tumor resection and preserving functionally relevant tissue structures depends on precise identification of tumor-free resection margins during surgery. Fluorescence-guided surgery (FGS), by intraoperative detection of tumor cells using a fluorescent tracer, may guide surgical excision and identify tumor-positive resection margins. Using a literature survey on potential surface molecules followed by immunohistochemical validation, we identified CD44 variant 6 (CD44v6) as a constitutively expressed antigen in the invasion zone of HNSCC lesions. The monoclonal anti-CD44v6 antibody BIWA was labeled with both a near-infrared fluorescent dye (IRDye800CW) and a radioactive label (Indium-111) and dual-modality imaging was applied in a locally invasive tumor mouse model. BIWA accurately detected human HNSCC xenografts in mice with a tumor uptake of 54 ± 11% ID/g and invasion regions with an accuracy of 94%. When dissected under clinical-like conditions, tumor remnants approximately 0.7 mm in diameter consisting of a few thousand cells were identified by fluorescence imaging, resulting in reliable dissection of invasive microregions. These data indicate that CD44v6 is a suitable target for reliable near-infrared detection and FGS of invasive HNSCC lesions in vivo.

Highlights

Head and neck squamous cell carcinomas (HNSCCs) are invasively growing tumors in a functionally delicate and important area with an overall five-year survival rate below 60%1
Candidate cell surface proteins, including c-Met, CD44 variant 6 (CD44v6), E-cadherin, epidermal growth factor receptor (EGFR), EMMPRIN and epithelial cell adhesion molecule (EpCAM), were identified based by a literature survey focusing on the percentage of positive tumors, the homogeneity of expression within the same tumor and whether the protein was expressed on the epithelium or the tumor stroma
CD44v6 is expressed in HNSCC across all tumor stages, with varying trends in T stage and/or nodal status[25,26,27,28]

Summary

Introduction

Head and neck squamous cell carcinomas (HNSCCs) are invasively growing tumors in a functionally delicate and important area with an overall five-year survival rate below 60%1. In functionally critical areas, such as the head and neck region, maximizing surgical margins has to be weighed against loss of functional tissue resulting in compromised quality of life post surgery[3] Developments such as intraoperative histology and image-guided surgery aim to more accurately delineate the tumor border during surgery, enabling more accurate tumor resection. Improved signal detection has been achieved by conjugating fluorophores in the near-infrared (NIR) range of 650–900 nm with targeting antibody binding extracellular epitopes preferentially expressed on tumor cells, allowing macro- and microscopic detection of even small tumors and tumor subregions[5] This resulted in a range of cancer-targeting antibodies developed for FGS surgery to validate molecular targets, establish conjugate safety and develop sensitive imaging devices[6,7,8]. We identify CD44v6 as candidate and apply anti-CD44v6 antibody BIWA for sensitive detection of the invasion margins in HNSCC in a preclinical mouse model

Methods

Results

Conclusion