Biology subjects

Clarke, D. T.

Publications and source records attributed to Clarke, D. T..

3 recordsLinked to original sources

bioRxiv2026

Disrupting aberrant EGFR catalytic trimers reverses T790M gefitinib resistance

Epidermal growth factor receptor (EGFR) mutations drive up to 50% of non-small-cell lung cancers (NSCLC). Although tyrosine kinase inhibitors provide substantial clinical benefit, remissions are prematurely terminated by the inevitable acquisition of on-target resistance. Beyond structural changes that alter ATP-pocket affinity, EGFR oligomerization drives this resistance, though the underlying mechanisms remain unclear. Here we show that progressive secondary and tertiary resistant NSCLC EGFR-mutants form ligand-free cell surface oligomers that contain catalytic trimers instead of the canonical dimers found within these oligomers in wild-type and gefitinib-sensitive EGFR-mutants. Genetically disrupting these pathological trimers into dimers via a single-point mutation rewires downstream signaling, decelerates tumor progression, and reverses gefitinib resistance in vivo. Conversely, genetic engineering of dimers into trimers reinstates normal tumor growth. These findings reveal a structural vulnerability specific to these refractory variants, demonstrating that targeting intra-oligomer interactions can overcome resistance, and providing a blueprint for protein-protein interface modulation strategies in NSCLC.

cancer biology↗

bioRxiv2023

The T766M-EGFR lung cancer mutation promotes tumor growth by exploiting newfound assembly mechanisms in ligand-free EGFR oligomers

Epidermal growth factor receptor (EGFR) is central to cell growth in physiology and pathophysiologies, including non-small cell lung cancer (NSCLC). EGFR has been successfully targeted with tyrosine kinase inhibitor generations, but the missense secondary T766M mutation is a common cause of resistance. Overcoming this therapeutic challenge has been hindered by poor understanding of how T766M dysregulates EGFR function leading to tumor progression. Here we show that T766M amplifies tumor growth in vivo by exploiting newly discovered oligomer assembly mechanisms employed by wild type (WT)-EGFR to maintain ligand-independent basal phosphorylation. These mechanisms, also shared by drug-resistant exon 20 EGFR insertions, reveal tumor growth promoting functions for hitherto orphan transmembrane and kinase interfaces and for the ectodomain tethered conformation of EGFR. Placing our findings into the context of a ligand-free oligomer structure model, we provide a framework for future drug discovery directed at tackling EGFR mutations in cancer by disabling oligomer-assembling interactions.

cancer biology↗

bioRxiv2022

Intranasal delivery of lipid nanoparticle encapsulated SARS-CoV-2 and RSV-targeting siRNAs reduces lung infection

RNA interference (RNAi) is an emerging and promising therapy for a wide range of respiratory viral infections. This highly specific suppression can be achieved by the introduction of short-interfering RNA (siRNA) into mammalian systems, resulting in the effective reduction of viral load. Unfortunately, this has been hindered by the lack of a good delivery system, especially via the intranasal (IN) route. Here, we have developed an IN siRNA encapsulated lipid nanoparticle (LNP) in vivo delivery system that is highly efficient at targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and respiratory syncytial virus (RSV) in infected mouse lungs. Importantly, IN siRNA delivery without the aid of LNPs abolishes anti-SARS-CoV-2 activity in vivo. Our approach using LNPs as the delivery vehicle overcomes the significant barriers seen with IN delivery of siRNA therapeutics and is a significant advancement in our ability to delivery siRNAs. The studies presented here demonstrates an attractive alternate therapeutic delivery strategy for the treatment of both future and emerging respiratory viral diseases.

microbiology↗