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 EGFR-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 in vivo 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.Significance:EGFR-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 EGFR-mutant NSCLC. Cancer Res; 78(17); 5094-106. ©2018 AACR.

• Authors: Cecilia Lopez Sambrooks, Marta Baro, Amanda Quijano, Azeet Narayan, Wei Cui, Patricia Greninger, Regina Egan, Abhijit Patel, Cyril H Benes, W Mark Saltzman, Joseph N Contessa
• Journal: Cancer research (Cancer Res) Vol. 78 Issue 17 Pg. 5094-5106 (09 01 2018) ISSN: 1538-7445 [Electronic] United States
• PMID: 30026325 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: ©2018 American Association for Cancer Research.

Chemical References

• Benzamides
• CID2519269
• Membrane Proteins
• Protein Kinase Inhibitors
• Sulfonamides
• Hexosyltransferases
• dolichyl-diphosphooligosaccharide - protein glycotransferase
• EGFR protein, human
• ErbB Receptors
• Gefitinib

Topics

• A549 Cells
• Animals
• Apoptosis (drug effects)
• Benzamides (chemistry, pharmacology)
• Carcinoma, Non-Small-Cell Lung (drug therapy, genetics, pathology)
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Drug Resistance, Neoplasm (drug effects, genetics)
• ErbB Receptors (antagonists & inhibitors, genetics)
• Gefitinib (adverse effects, therapeutic use)
• Hexosyltransferases (antagonists & inhibitors, genetics)
• Humans
• Membrane Proteins (antagonists & inhibitors, genetics)
• Mice
• Mutation (drug effects)
• Nanoparticles (chemistry)
• Protein Kinase Inhibitors (adverse effects, therapeutic use)
• Sulfonamides (chemistry, pharmacology)
• Xenograft Model Antitumor Assays