Preclinical screening of anti‐HER2 nanobodies for molecular imaging of breast cancer

Abstract

Accurate determination of tumor human epidermal growth factor receptor 2 (HER2)-status in breast cancer patients is possible via noninvasive imaging, provided adequate tracers are used. In this study, we describe the generation of a panel of 38 nanobodies, small HER2-binding fragments that are derived from heavy-chain-only antibodies raised in an immunized dromedary. In search of a lead compound, a subset of nanobodies was biochemically characterized in depth and preclinically tested for use as tracers for imaging of xenografted tumors. The selected compound, 2Rs15d, was found to be stable and to interact specifically with HER2 recombinant protein and HER2-expressing cells in ELISA, surface plasmon resonance, flow cytometry, and radioligand binding studies with low nanomolar affinities, and did not compete with anti-HER2 therapeutic antibodies trastuzumab and pertuzumab. Single-photon-emission computed tomography (SPECT) imaging quantification and biodistribution analyses showed that (99m)Tc-labeled 2Rs15d has a high tumor uptake in 2 HER2(+) tumor models, fast blood clearance, low accumulation in nontarget organs except kidneys, and high concomitant tumor-to-blood and tumor-to-muscle ratios at 1 h after intravenous injection. These values were dramatically lower for an irrelevant control (99m)Tc-nanobody and for (99m)Tc-2Rs15d targeting a HER2(-) tumor.

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

“…[517] Specifically, nanbobodies have been used as antagonistic drugs [518] and targeting agents of effector domains [519] in cancer immunotherapy. On the other hand, several molecular imaging modalities of SPECT [520] and PET, [521] optical imaging, [522] and ultrasound imaging [523] have been actively directed toward the target by means of nanobodies conjugated to them.…”

Camelid single-domain antibody fragments: Uses and prospects to investigate protein misfolding and aggregation, and to treat diseases associated with these phenomena

“…These features are essentially all fulfilled by nanobodies [185,186] and a series of studies suggest that nanobodies could become the next generation of magic bullets for immune-imaging [182,187]. For example, radiolabelled nanobodies that are specific to carcino embryonic antigen (i.e.…”

“…the epidermal growth factor and the HER2 receptor expressed on cancer cells) show rapid (i.e. 1 h after injection) and specific uptake in mouse tumour model [187]. Due to the high specificity, high tissues penetrance and short biological half-life of the nanobody, imaging with sufficient contrast is possible shortly after its injection which, from a practical point of view, will be much appreciable for the patients.…”

“…Due to the high specificity, high tissues penetrance and short biological half-life of the nanobody, imaging with sufficient contrast is possible shortly after its injection which, from a practical point of view, will be much appreciable for the patients. It also allows the use of short-lived, and thus less toxic, radionuclei [187].…”

Nuevos desarrollos en el diagnóstico de parásitos

“…Therefore, we now identified a nanobody against HER-2, a tumor associated surface marker of some breast cancer cells (Vaneycken, et al, 2011). We are currently producing this nanobody under good manufactuing practice conditions and hope that we will be able to use this nanobody to screen breast cancer patients to identify those that will benefit from treatment with traztuzmab.…”