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Biology subjects

Rolfe, D. J.

Publications and source records attributed to Rolfe, D. J..

3 recordsLinked to original sources

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↗

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↗

The guidance and adhesion protein FLRT2 dimerizes in cis via dual Small-X3-Small transmembrane motifs

Fibronectin Leucine-rich Repeat Transmembrane (FLRT 1-3) proteins are a family of broadly expressed single-spanning transmembrane receptors that play key roles in development. Their extracellular domains mediate homotypic cell-cell adhesion and heterotypic protein interactions with other receptors to regulate cell adhesion and guidance. These in trans FLRT interactions determine the formation of signaling complexes of varying complexity and function. Whether FLRTs also interact at the surface of the same cell, in cis, remains unknown. Here, molecular dynamics simulations reveal two dimerization motifs in the FLRT2 transmembrane helix. Single particle tracking experiments show that these Small-X3-Small motifs synergize with a third dimerization motif encoded in the extracellular domain to permit the cis association and co-diffusion patterns of FLRT2 receptors on cells. These results may point to a competitive switching mechanism between in cis and in trans interactions which suggests that homotypic FLRT interaction mirrors the functionalities of classic adhesion molecules. FieldsStructural Biology and Biophysics / Computational Biology

biophysics↗