Nanoscale Mapping of EGFR and c‑MET Protein Environments on Lung Cancer Cell Surfaces via Therapeutic Antibody Photocatalyst Conjugates

Receptor tyrosine kinases are involved in essential signaling roles that impact cell growth, differentiation, and proliferation. The overexpression or mutation of these proteins can lead to aberrant signaling that has been directly linked to a number of diseases including cancer cell formation and progression. This has led to intense clinical focus on modulating RTK activity through direct targeting of signaling activity or cell types harboring aberrant RTK behavior. In particular, epidermal growth factor receptor (EGFR) has attracted intense clinical attention due to the impact of inhibiting this RTK on tumor growth. However, mutations incurred through targeting EGFR have led to therapeutic resistance that involves not only direct mutations to the EGFR protein but also the involvement of other RTKs, such as c-MET, that can overcome therapeutic-based EGFR inhibition effects. This has, not surprisingly, led to co-targeting strategies of RTKs such as EGFR and c-MET to overcome resistance mechanisms. While the ability to co-target these proteins has led to success in the clinic, a more comprehensive understanding of their proximal environments, particularly in the context of therapeutic modalities, could further enhance both our understanding of their signaling biology and provide additional avenues for targeting these surface proteins. Thus, to investigate EGFR and c-MET protein microenvironments, we utilized our recently developed iridium photocatalyst-based microenvironment mapping technology to catalog EGFR and c-MET surface environments on non-small cell lung cancer cell lines. Through this approach, we enriched EGFR and c-MET from the cell surface and identified known EGFR and c-MET associators as well as previously unidentified proximal proteins

Nanoscale Mapping of EGFR and c‑MET Protein Environments on Lung Cancer Cell Surfaces via Therapeutic Antibody Photocatalyst Conjugates

Receptor tyrosine kinases are involved in essential signaling roles that impact cell growth, differentiation, and proliferation. The overexpression or mutation of these proteins can lead to aberrant signaling that has been directly linked to a number of diseases including cancer cell formation and progression. This has led to intense clinical focus on modulating RTK activity through direct targeting of signaling activity or cell types harboring aberrant RTK behavior. In particular, epidermal growth factor receptor (EGFR) has attracted intense clinical attention due to the impact of inhibiting this RTK on tumor growth. However, mutations incurred through targeting EGFR have led to therapeutic resistance that involves not only direct mutations to the EGFR protein but also the involvement of other RTKs, such as c-MET, that can overcome therapeutic-based EGFR inhibition effects. This has, not surprisingly, led to co-targeting strategies of RTKs such as EGFR and c-MET to overcome resistance mechanisms. While the ability to co-target these proteins has led to success in the clinic, a more comprehensive understanding of their proximal environments, particularly in the context of therapeutic modalities, could further enhance both our understanding of their signaling biology and provide additional avenues for targeting these surface proteins. Thus, to investigate EGFR and c-MET protein microenvironments, we utilized our recently developed iridium photocatalyst-based microenvironment mapping technology to catalog EGFR and c-MET surface environments on non-small cell lung cancer cell lines. Through this approach, we enriched EGFR and c-MET from the cell surface and identified known EGFR and c-MET associators as well as previously unidentified proximal proteins

Near-Infrared Photoredox Catalyzed Tryptophan Functionalization for Peptide Stapling and Protein Labeling in Complex Tissue Environments

The chemical transformation of aromatic amino acids has emerged as an attractive alternative to non-selective lysine or cysteine labeling for the modification of biomolecules. However, this strategy has largely been limited by the scope of functional groups and biocompatible reaction conditions available. Herein, we report the implementation of near-infrared-activatable photocatalysts, TTMAPP and n-Pr-DMQA+, capable of generating fluoroalkyl radicals for selective tryptophan functionalization within simple and complex biological systems. At the peptide level, a diverse set of iodo-perfluoroalkyl reagents were used to install bioorthogonal handles for downstream applications or link inter- or intramolecular tryptophan residues for peptide stapling. We also found this photoredox transformation amenable to biotinylation of intracellular proteins in live cells for downstream confocal imaging and mass spectrometry-based analysis. Given the inherent tissue penetrant nature of near-infrared light we further demonstrated the utility of this technology to achieve photocatalytic protein fluoroalkylation in physiologically relevant tissue and tumor environments

Near-Infrared Photoredox Catalyzed Fluoroalkylation Strategy for Protein Labeling in Complex Tissue Environments

The chemical transformation of aromatic amino acids has emerged as an attractive alternative to nonselective lysine or cysteine labeling for the modification of biomolecules. However, this strategy has largely been limited by the scope of functional groups and the biocompatible reaction conditions available. Herein, we report the implementation of near-infrared-activatable photocatalysts, TTMAPP and n-Pr-DMQA+, capable of generating fluoroalkyl radicals for peptide functionalization and protein labeling within simple and complex biological systems. At the peptide level, a diverse set of iodoperfluoroalkyl reagents were used in the functionalization and stapling of tryptophan residues. Using this photoredox catalyzed perfluoroalkylation technology, we achieved biotinylation of intracellular proteins in live cells. Notably, given the inherent tissue penetrant nature of near-infrared light, we further demonstrated the utility of this technology to achieve photocatalytic protein fluoroalkylation in patient-derived normal and tumor tissue for downstream confocal imaging and mass spectrometry-based proteomic analysis

Discovering chemical structure: general discussion

This article is a discussion of the paper "Spiers Memorial Lecture: How to do impactful research in artificial intelligence for chemistry and materials science" by Alán Aspuru-Guzik et al. (Faraday discussions, 2025, DOI: 10.1039/D4FD00153B)