Oligosaccharyltransferase Inhibition Overcomes Therapeutic Resistance to EGFR Tyrosine Kinase Inhibitors

Abstract

Asparagine (N)-linked glycosylation is a posttranslational modification essential for the function of complex transmembrane proteins. However, targeting glycosylation for cancer therapy has not been feasible due to generalized effects on all glycoproteins. Here, we perform sensitivity screening of 94 lung cancer cell lines using NGI-1, a small-molecule inhibitor of the oligosaccharyltransferase (OST) that partially disrupts N-linked glycosylation, and demonstrate a selective loss of tumor cell viability. This screen revealed NGI-1 sensitivity in just 11 of 94 (12%) cell lines, with a significant correlation between OST and EGFR inhibitors. In -mutant non-small cell lung cancer with EGFR tyrosine kinase inhibitor (TKI) resistance (PC9-GR, HCC827-GR, and H1975-OR), OST inhibition maintained its ability to induce cell-cycle arrest and a proliferative block. Addition of NGI-1 to EGFR TKI treatment was synthetic lethal in cells resistant to gefitinib, erlotinib, or osimertinib. OST inhibition invariably disrupted EGFR N-linked glycosylation and reduced activation of receptors either with or without the T790M TKI resistance mutation. OST inhibition also dissociated EGFR signaling from other coexpressed receptors like MET via altered receptor compartmentalization. Translation of this approach to preclinical models was accomplished through synthesis and delivery of NGI-1 nanoparticles, confirmation of activity through molecular imaging, and demonstration of significant tumor growth delay in TKI-resistant HCC827 and H1975 xenografts. This therapeutic strategy breaks from kinase-targeted approaches and validates N-linked glycosylation as an effective target in tumors driven by glycoprotein signaling.-mutant NSCLC is incurable despite the marked sensitivity of these tumors to EGFR TKIs. These findings identify N-linked glycosylation, a posttranslational modification common to EGFR and other oncogenic signaling proteins, as an effective therapeutic target that enhances tumor responses for -mutant NSCLC..

N-Glycosylation regulates ligand-dependent activation and signaling of vascular endothelial growth factor receptor 2 (VEGFR2)

“…Analyses of epidermal growth factor receptors (EGFR) suggest that, independent of lectin-mediated effects, specific monosaccharides attached to N-linked glycans via specific linkages regulate receptor dimerization: both sialylation and outerarm fucosylation of EGFR N-linked glycans at specific sites within the receptor lead to decreased receptor dimerization and phosphorylation, whereas core fucosylation has the opposite effect (36,37,41). Intriguingly, inhibition of N-linked glycosylation with tunicamycin reduces RTK signaling in tumor cells (42)(43)(44)(45)(46). Understanding how changes in glycosylation lead to dysregulation of VEGFR2-mediated signaling is essential to the development of therapeutic strategies that facilitate tumor vessel normalization, prevent metastasis, and expand the reach of immunotherapy.…”

PWAS: proteome-wide association study—linking genes and phenotypes by functional variation in proteins

“… 0.024 (*) − 0.037 Moderate, acts as tumor suppressor in breast and other cancer types [ 24 ] p = 1.5E−3 p = 0.016 OSTC Oligosaccharyltransferase complex non-catalytic subunit 4 rs17038839 rs202168879 0.01 (*) 0.96 n.s. 0.024 (*) 0.026 Weak, subunit of the OST complex which has been associated with lung and ovarian cancer [ 25 , 26 ] p = 9.1E−4 p = 0.016 CDK2AP2 / DOC-1R Cyclin-dependent kinase 2-associated protein 2 11 rs147242558 rs530762126 0.024 (*) 1 n.s. 7.8E−3 (*) − 5.4E−3 Strong, inhibits CDK2 and G1/S phase transition, a paralog of p14 and CDK2AP1, binds CDK2AP1 [ 27 , 28 ] p = 2.7E−3 p = 0.4 POU5F1B / BRN4 POU class 5 homeobox 1B 8 *rs6983267 *rs6998061 0.027 (*) 0.02 (*) 0.09 1 n.s.…”

Analysis of the Effect of Increased α2,3-Sialylation on RTK Activation in MKN45 Gastric Cancer Spheroids Treated with Crizotinib

“…Moreover, combination therapy could be used to tackle both acquired and intrinsic resistance. Furthermore, the use of molecules targeting N-glycosylation, such as the small molecule NGI-1, have shown promising results as a second-hit for cancer cells addicted to RTKs activation and resistant to TKIs [62]. Further development of 3D-cell culture techniques, especially the automation and additional advances of the high-throughput technologies, will certainly contribute to the progress in the drug discovery field.…”