Targeting the activated allosteric conformation of the endothelin receptor B in melanoma with an antibody-drug conjugate: mechanisms and therapeutic efficacy.

Background: Endothelin 1 receptors are one of the drivers of tumor progression in many cancers. Inhibition of their signaling pathways with antagonist drugs has been the subject of numerous clinical trials, but the results have not met expectations probably due to the high endothelin concentrations in the tumor microenvironment and their unusually high affinity for their receptors.

Methods: We previously reported the rendomab B49 antibody (RB49) exhibiting a preferential affinity for the activated conformation of human endothelin B receptor (ET), not displaced by high endothelin levels, and without any pharmacological properties that could inhibit the division of melanoma cells.

Preoperative PET imaging and fluorescence-guided surgery of human glioblastoma using dual-labeled antibody targeting ET receptors in a preclinical mouse model: A theranostic approach.

Glioblastoma (GBM) poses significant challenges regarding complete tumor removal due to its heterogeneity and invasiveness, emphasizing the need for effective therapeutic options. In the last two decades, fluorescence-guided surgery (FGS), employing fluorophores such as 5-aminolevulinic acid (5-ALA) to enhance tumor delineation, has gained attraction among neurosurgeons. However, some low-grade tumors do not show any accumulation of the tracers, and the lack of patient stratification represents an important limitation.

Synthesis and Preclinical Fluorescence Imaging of Dually Functionalized Antibody Conjugates Targeting Endothelin Receptor-Positive Tumors.

For the past two decades, the emerging role of the endothelin (ET) axis in cancer has been extensively investigated, and its involvement in several mechanisms described as "hallmarks of cancer" has clearly highlighted its potential as a therapeutic target. Despite the growing interest in finding effective anticancer drugs, no breakthrough treatment has successfully made its way to the market. Recently, our team reported the development of a new immuno-positron emission tomography probe targeting the ET A receptor (ET, one of the ET receptors) that allows the successful detection of ET glioblastoma, paving the way for the elaboration of novel antibody-based strategies.

ImmunoPET imaging-based pharmacokinetic profiles of an antibody and its Fab targeting endothelin A receptors on glioblastoma stem cells in a preclinical orthotopic model.

Background: The resistance of glioblastoma stem cells (GSCs) to treatment is one of the causes of glioblastoma (GBM) recurrence. Endothelin A receptor (ET) overexpression in GSCs constitutes an attractive biomarker for targeting this cell subpopulation, as illustrated by several clinical trials evaluating the therapeutic efficacy of endothelin receptor antagonists against GBM. In this context, we have designed an immunoPET radioligand combining the chimeric antibody targeting ET, chimeric-Rendomab A63 (xiRA63), with Zr isotope and evaluated the abilities of xiRA63 and its Fab (ThioFab-xiRA63) to detect ET tumors in a mouse model xenografted orthotopically with patient-derived Gli7 GSCs.

First Comparison Study of the and Properties of a Randomly and Site-Specifically Conjugated SPECT/NIRF Monomolecular Multimodal Imaging Probe (MOMIP) Based on an aza-BODIPY Fluorophore.

Among all approaches in molecular imaging, the combination of near-infrared fluorescence imaging (NIRF) with radioisotopic imaging (PET or SPECT) allows one to benefit from the advantages of each of the imaging techniques, which are very complementary and of comparable sensitivity. To this end, the construction of monomolecular multimodal probes (MOMIP) has made it possible to combine the two imaging modalities within the same molecule, thus limiting the number of bioconjugation sites and yielding more homogeneous conjugates compared with those prepared through sequential conjugation. However, in order to optimize the bioconjugation strategy and, at the same time, the pharmacokinetic and biodistribution properties of the resulting imaging agent, a site-specific approach may be preferred.