Rapid optical imaging of human breast tumour xenografts using anti-HER2 VHHs site-directly conjugated to IRDye 800CW for image-guided surgery

• Published in: European journal of nuclear medicine and molecular imaging Vol. 40; no. 11; pp. 1718 - 1729
• Main Authors: Kijanka, Marta, Warnders, Frank-Jan, El Khattabi, Mohamed, Lub-de Hooge, Marjolijn, van Dam, Gooitzen M., Ntziachristos, Vasilis, de Vries, Liesbeth, Oliveira, Sabrina, van Bergen en Henegouwen, Paul M. P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2013; Springer Nature B.V
• Subjects: Animals; Antibody Affinity; Benzenesulfonates - pharmacokinetics; Benzenesulfonates - therapeutic use; Breast cancer; Breast Neoplasms - pathology; Breast Neoplasms - surgery; Camelids, New World; Cancer surgery; Cardiology; Escherichia coli; Fluorescent Dyes - pharmacokinetics; Fluorescent Dyes - therapeutic use; Humans; Imaging; Indoles - pharmacokinetics; Indoles - therapeutic use; MCF-7 Cells; Medical imaging; Medicine; Medicine & Public Health; Mice; Mice, Inbred BALB C; Mice, Nude; Nuclear Medicine; Oncology; Optical Imaging - methods; Original Article; Orthopedics; Radiology; Receptor, ErbB-2 - immunology; Single-Domain Antibodies - immunology; Single-Domain Antibodies - therapeutic use; Surgery, Computer-Assisted - methods; Tomography; Xenograft Model Antitumor Assays; Nanobody; Optical imaging; Breast cancer; HER2; VHH
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-013-2471-2

Purpose Molecular optical imaging using monoclonal antibodies is slow with low tumour to background ratio. We used anti-HER2 VHHs conjugated to IRDye 800CW to investigate their potential as probes for rapid optical molecular imaging of HER2-positive tumours by the determination of tumour accumulation and tumour to background levels. Methods Three anti-HER2 VHHs (11A4, 18C3, 22G12) were selected with phage display and produced in Escherichia coli . Binding affinities of these probes to SKBR3 cells were determined before and after site-specific conjugation to IRDye 800CW. To determine the potential of VHH-IR as imaging probes, serial optical imaging studies were carried out using human SKBR3 and human MDA-MB-231 xenograft breast cancer models. Performance of the anti-HER2 VHH-IR was compared to that of trastuzumab-IR and a non-HER2-specific VHH-IR. Image-guided surgery was performed during which SKBR3 tumour was removed under the guidance of the VHH-IR signal. Results Site-specific conjugation of IRDye 800CW to three anti-HER2 VHHs preserved high affinity binding with the following dissociation constants (K D ): 11A4 1.9 ± 0.03, 18C3 14.3 ± 1.8 and 22G12 3.2 ± 0.5 nM. Based upon different criteria such as binding, production yield and tumour accumulation, 11A4 was selected for further studies. Comparison of 11A4-IR with trastuzumab-IR showed ∼20 times faster tumour accumulation of the anti-HER2 VHH, with a much higher contrast between tumour and background tissue (11A4-IR 2.5 ± 0.3, trastuzumab-IR 1.4 ± 0.4, 4 h post-injection). 11A4-IR was demonstrated to be a useful tool in image-guided surgery. Conclusion VHH-IR led to a much faster tumour accumulation with high tumour to background ratios as compared to trastuzumab-IR allowing same-day imaging for clinical investigation as well as image-guided surgery.