Researchers develop novel strategy to selectively target tumor microenvironments

A new collaborative study reports the discovery and application of a novel therapeutic strategy to selectively target EGFR and other kinases with controlled release in tumor microenvironments to improve therapeutic efficacy, with promising results. The results were published in Bioorganic Chemistry.

The study was carried out by researchers from the University of Eastern Finland, as well as from North Carolina State University, USA, the University of North Carolina at Chapel Hill, USA, and the University of Oslo, Norway.

Tyrosine kinase inhibitors (TKIs) are clinically limited by undesired inhibition of the Epidermal Growth Factor Receptor (EGFR) and other kinases in healthy tissues, causing toxicities and narrowing the drug's therapeutic window.

In this study, we evaluated carbamate masking of the 4-anilinoquinazoline hinge nitrogen as a scaffold-centred strategy to modulate exposure and enable controlled activation across a panel of EGFR-TKIs." 

Christopher Asquith, Senior Researcher, School of Pharmacy, University of Eastern Finland

The researchers explored a β-eliminative sulfone linker design for localised release from alginate hydrogels. Hydrolysis profiling revealed that efficient parent drug release occurred only at basic pH, defining key constraints for depot formulations in mildly acidic tumor microenvironments. In parallel, they developed nitroreductase (NTR)-activatable AQ-TKI prodrugs. The nitroimidazole carbamate increased polarity and adjusted solubility while maintaining favourable pharmacokinetic compound profiles. All prodrugs were chemically stable under physiologically relevant conditions and underwent efficient NTR-dependent uncaging to regenerate the parent TKIs.

Molecular dynamics simulations and Boltz-2 protein-ligand affinity predictions showed weakened binding and reduced kinase target space for intact prodrugs relative to the parent compounds, consistent with higher IC₅₀ values in cell-free EGFR assays and supporting attenuated basal activity prior to activation. Together, these results establish AQ carbamate derivatization as a generalisable platform for EGFR-TKI prodrug design and provide quantitative design rules linking scaffold masking, stability, activation and target engagement.

"The carbamate masking of 4-anilinoquinazoline TKIs enables controlled prodrug activation and reduces EGFR binding and basal activity. This proof-of-concept study demonstrates broad applicability to clinically used and investigational compounds. This work is a significant contribution to both the targeted therapy and the anti-cancer research field," adds Professor Joshua Pierce of North Carolina State University.