Expanded Application of a Photoaffinity Probe to Study Epidermal Growth Factor Receptor Tyrosine Kinase with Functional Activity

Deciphering Drug Targets and Actions with Single-Cell and Spatial Resolution

Recent advances in chemical, molecular, and genetic approaches have provided us with an unprecedented capacity to identify drug-target interactions across the whole proteome and genome. Meanwhile, rapid developments of single-cell and spatial omics technologies are revolutionizing our understanding of the molecular architecture of biological systems. However, a significant gap remains in how we align our understanding of drug actions, traditionally based on molecular affinities, with the in vivo cellular and spatial tissue heterogeneity revealed by these newer techniques. Here, we review state-of-the-art methods for profiling drug-target interactions and emerging multiomics tools to delineate the tissue heterogeneity at single-cell resolution. Highlighting the recent technical advances enabling high-resolution, multiplexable in situ small-molecule drug imaging (clearing-assisted tissue click chemistry, or CATCH), we foresee the integration of single-cell and spatial omics platforms, data, and concepts into the future framework of defining and understanding in vivo drug-target interactions and mechanisms of actions.

Design, synthesis and biological evaluation of small molecule fluorescent probes targeting EGFR for tumor detection and treatment

The epidermal growth factor receptor (EGFR) is a tyrosine kinase receptor that plays a crucial role in cell differentiation and tumor progression, and its overexpression is closely associated with the development and metastasis of multiple cancers. The development of a fluorescent probe capable of targeting EGFR while simultaneously integrating diagnostic and therapeutic functions could have a profound impact on the treatment of related cancers. In this study, we developed a series of EGFR-targeting probes that consisted of an environment-sensitive 1,8-naphthalimide fluorophore, a linker unit and a targeting unit (gefitinib), using a coupling strategy. The synthesized probes were first evaluated for their spectroscopic properties and cytotoxicities against different cell lines, which were selected based on their intrinsic EGFR expression levels. Remarkably, among the probes tested, GP1 showed outstanding environmental sensitivity and exhibited a specific response to tumor cells that overexpress EGFR. Furthermore, the representative probe GP1 was evaluated for its EGFR-specific targeting ability in live-cell fluorescence imaging and in vivo xenograft imaging, as well as its in vivo anti-tumor activity. The results showed that the probe GP1 had excellent EGFR-specific targeting ability, exhibited competitive replacement behavior towards the EGFR inhibitor gefitinib, and demonstrated potent anti-tumor effects in a CT-26 tumor-bearing mouse model. Overall, as a turn-on EGFR targeting fluorescent ligand, GP1 holds immense promise as a valuable tool for tumor detection and treatment.