Ligand-Gated Ion Channels as Targets for Treatment and Management of Cancers

Ligand-gated ion channels are an ionotropic receptor subtype characterized by the binding of an extracellular ligand, followed by the transient passage of ions through a transmembrane pore. Ligand-gated ion channels are commonly subcategorized into three superfamilies: purinoreceptors, glutamate receptors, and Cys-loop receptors. This classification is based on the differing topographical morphology of the receptors, which in turn confers functional differences. Ligand-gated ion channels have a diverse spatial and temporal expression which implicate them in key cellular processes. Given that the transcellular electrochemical gradient is finely tuned in eukaryotic cells, any disruption in this homeostasis can contribute to aberrancies, including altering the activity of pro-tumorigenic molecular pathways, such as the MAPK/ERK, RAS, and mTOR pathways. Ligand-gated ion channels therefore serve as a potential targetable system for cancer therapeutics. In this review, we analyze the role that each of the three ligand-gated ion channel superfamilies has concerning tumor proliferation and as a target for the treatment of cancer symptomatology.

Label-Free Antifouling Photoelectrochemical Sensing Strategy for Detecting Breast Tumor Cells Based on Ligand-Receptor Interactions

Biomarker expression both on the cell surface and in serum is directly related to the pathological process of tumor. Based on the interaction between the ligand and the protein receptor, a label-free photoelectrochemical (PEC) biosensing interface with good antifouling ability was proposed for tumor cell detection. TiO₂ nanotube (NT) arrays were used as the substrate to enhance the ability of the biosensor to capture the target. Mercapto-terminated 8-arm poly(ethylene glycol) was introduced onto the electrode surface by the deposition of Au nanoparticles on TiO₂ NTs, creating an antifouling molecular layer. The recognition ligand hyaluronic acid (HA) was functionalized by dopamine and introduced onto the sensing surface based on the unique chelating interaction between the catechol group and the titanium atom. Benefitting from the specific recognition of HA with CD44 and the 3D porous structures of NTs, the constructed PEC biosensor showed excellent abilities toward the detection of MDA-MB-231 breast tumor cells and the soluble form of CD44. The ligand-receptor PEC sensing strategy has promising potential for the detection of tumor cells and protein biomarkers.

Integrated nanotechnology platform for tumor-targeted multimodal imaging and therapeutic cargo release

A major challenge of targeted molecular imaging and drug delivery in cancer is establishing a functional combination of ligand-directed cargo with a triggered release system. Here we develop a hydrogel-based nanotechnology platform that integrates tumor targeting, photon-to-heat conversion, and triggered drug delivery within a single nanostructure to enable multimodal imaging and controlled release of therapeutic cargo. In proof-of-concept experiments, we show a broad range of ligand peptide-based applications with phage particles, heat-sensitive liposomes, or mesoporous silica nanoparticles that self-assemble into a hydrogel for tumor-targeted drug delivery. Because nanoparticles pack densely within the nanocarrier, their surface plasmon resonance shifts to near-infrared, thereby enabling a laser-mediated photothermal mechanism of cargo release. We demonstrate both noninvasive imaging and targeted drug delivery in preclinical mouse models of breast and prostate cancer. Finally, we applied mathematical modeling to predict and confirm tumor targeting and drug delivery. These results are meaningful steps toward the design and initial translation of an enabling nanotechnology platform with potential for broad clinical applications.