Optimization of Peptide Linker-Based Fluorescent Ligands for the Histamine H1 Receptor

BODIPY-Based Molecules for Biomedical Applications

BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) derivatives have attracted attention as probes in applications like imaging and sensing due to their unique properties like (1) strong absorption and emission in the visible and near-infrared regions of the electromagnetic spectrum, (2) strong fluorescence and (3) supreme photostability. They have also been employed in areas like photodynamic therapy. Over the last decade, BODIPY-based molecules have even emerged as candidates for cancer treatments. Cancer remains a significant health issue world-wide, necessitating a continuing search for novel therapeutic options. BODIPY is a flexible fluorophore with distinct photophysical characteristics and is a fascinating drug development platform. This review provides a comprehensive overview of the most recent breakthroughs in BODIPY-based small molecules for cancer or disease detection and therapy, including their functional potential.

Chemical biology fluorescent tools for in vitro investigation of the multidrug resistant P-glycoprotein (P-gp) expression in tumor cells

Selective P-glycoprotein (P-gp)-targeted fluorescent conjugates are desirable tools to investigate the role of P-gp, a protein strongly implicated in mediating multidrug resistance and a major cause of chemotherapy failure. Herein, we report the development of 25 novel fluorescent small-molecule conjugates with varying physicochemical and optical properties, and their biological evaluation in a cell model as P-gp targeted constructs. This investigation revealed relationships between molecular structure and cell behavior and uncovered the capacity of conjugates with varying fluorophores to selectively target P-gp. Sulfocyanine 3 labeled conjugates (5, 10, 24, 29, 34) showed a particular intracellular staining pattern. Other conjugates bearing a boron dipyrromethene (BODIPY) core (3, 8, 13, 22, 27 (BODIPY FL), 12 (BODIPY 564/570) and 4, 9 (BODIPY 650/665)) or a 7-nitrobenz-2-oxa-1,3-diazole (NBD) core (11, 30) showed potential for global P-gp direct detection and quantification. These fluorescent conjugates holds key advantages over existing methods for drug resistance evaluation with regards to P-gp expression and could be used as innovative tools in preclinical assays and clinical diagnosis.

Development and Characterization of a Highly Selective Turn-On Fluorescent Ligand for β3-Adrenergic Receptor

For the precise visualization of GPCR, subtype selectivity of turn-on fluorescent ligands is of major relevance. Although there are many thriving β-adrenergic receptors (β-ARs) probes, none of them are selective to the β₃-subtype, which severely limits the development of β₃-AR investigations. Using a polyethylene glycol (PEG) chain to conjugate the Py-5 fluorophore with mirabegron, we present here a highly selective fluorescent ligand, H2, for β₃-AR. It was established by the radioligand and NanoLuc-based bioluminescence resonance energy transfer (NanoBRET) binding experiments that molecule H2 has a substantially higher affinity for β₃-AR than the other two subtypes (1/3, 45-fold; 2/3, 16-fold). More crucially, when molecule H2 was incubated with β₃-AR, the turn-on fluorescent signals could be quickly released. The subsequent investigations, which included cell imaging, tissue imaging, and flow-cytometry analysis, proved that molecule H2 may make it possible to quickly and accurately fluorescently identify β₃-AR at different levels. We offer a prospective fluorescent turn-on ligand with exceptional selectivity for β₃-AR as a result of our combined efforts.