{"title":"Phosphoproteomic Analysis Identified Mutual Phosphorylation of FAK and Src as a Mechanism of Osimertinib Resistance in EGFR-Mutant Lung Cancer","authors":"Takehiro Tozuka MD , Rintaro Noro MD, PhD , Keisuke Yoshida PhD , Satoshi Takahashi MD, PhD , Mariko Hirao XX , Kuniko Matsuda XX , Yasuhiro Kato MD , Shinji Nakamichi MD, PhD , Susumu Takeuchi MD, PhD , Masaru Matsumoto MD, PhD , Akihiko Miyanaga MD, PhD , Shinobu Kunugi MD, PhD , Kazufumi Honda DDS, PhD , Jun Adachi PhD , Masahiro Seike MD, PhD","doi":"10.1016/j.jtocrr.2024.100668","DOIUrl":null,"url":null,"abstract":"<div><h3>Introduction</h3><p>Osimertinib is a standard treatment for patients with <em>EGFR</em>-mutant NSCLC. Although some osimertinib resistance mechanisms have been identified, nearly 50% of the mechanisms remain to be elucidated. This study was aimed at identifying non-genetic mechanisms underlying osimertinib resistance.</p></div><div><h3>Methods</h3><p>We established two osimertinib-resistant cell lines from <em>EGFR</em> mutation-positive PC-9 and HCC827 NSCLC cell lines (PC-9OR and HCC827OR, respectively) using a stepwise method. We compared the phosphoproteomic profiles of the osimertinib-resistant and parental cells using mass spectrometry. Upstream kinases were identified using the application Kinase Enrichment Analysis version 3.</p></div><div><h3>Results</h3><p>Phosphoproteomic analysis revealed 80 phosphorylation sites that were mutually up-regulated in PC-9OR and HCC827OR cells. The Kinase Enrichment Analysis version 3 analysis identified focal adhesion kinase (FAK) and proto-oncogene tyrosine-protein kinase Src (Src) as upstream kinases of these up-regulated phosphoproteins. The small-interfering RNA–mediated knockdown of FAK reduced Src phosphorylation and that of Src reduced FAK phosphorylation in both cell lines. Furthermore, FAK- or Src-specific small-interfering RNA treatments restored EGFR phosphorylation in PC-9OR and HCC827OR cells. The combination of FAK and Src inhibitors inhibited PC-9OR and HCC827OR cell proliferation in vitro and suppressed tumor growth in a xenograft mouse model. Immunohistochemistry of tumors from patients with <em>EGFR</em>-mutant NSCLC suggested that phosphorylated FAK and Src are involved in initial and acquired resistance to osimertinib.</p></div><div><h3>Conclusions</h3><p>Phosphoproteomic analysis may help elucidate the mechanisms of resistance to molecular-targeted therapies in lung cancer. Mutual phosphorylation of FAK and Src is involved in osimertinib resistance. Thus, FAK and Src inhibition may be novel treatment strategies for osimertinib-resistant NSCLC.</p></div>","PeriodicalId":17675,"journal":{"name":"JTO Clinical and Research Reports","volume":null,"pages":null},"PeriodicalIF":3.0000,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666364324000389/pdfft?md5=7b6560c60e702d1983547e4ee3c5ef18&pid=1-s2.0-S2666364324000389-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"JTO Clinical and Research Reports","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666364324000389","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ONCOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Introduction
Osimertinib is a standard treatment for patients with EGFR-mutant NSCLC. Although some osimertinib resistance mechanisms have been identified, nearly 50% of the mechanisms remain to be elucidated. This study was aimed at identifying non-genetic mechanisms underlying osimertinib resistance.
Methods
We established two osimertinib-resistant cell lines from EGFR mutation-positive PC-9 and HCC827 NSCLC cell lines (PC-9OR and HCC827OR, respectively) using a stepwise method. We compared the phosphoproteomic profiles of the osimertinib-resistant and parental cells using mass spectrometry. Upstream kinases were identified using the application Kinase Enrichment Analysis version 3.
Results
Phosphoproteomic analysis revealed 80 phosphorylation sites that were mutually up-regulated in PC-9OR and HCC827OR cells. The Kinase Enrichment Analysis version 3 analysis identified focal adhesion kinase (FAK) and proto-oncogene tyrosine-protein kinase Src (Src) as upstream kinases of these up-regulated phosphoproteins. The small-interfering RNA–mediated knockdown of FAK reduced Src phosphorylation and that of Src reduced FAK phosphorylation in both cell lines. Furthermore, FAK- or Src-specific small-interfering RNA treatments restored EGFR phosphorylation in PC-9OR and HCC827OR cells. The combination of FAK and Src inhibitors inhibited PC-9OR and HCC827OR cell proliferation in vitro and suppressed tumor growth in a xenograft mouse model. Immunohistochemistry of tumors from patients with EGFR-mutant NSCLC suggested that phosphorylated FAK and Src are involved in initial and acquired resistance to osimertinib.
Conclusions
Phosphoproteomic analysis may help elucidate the mechanisms of resistance to molecular-targeted therapies in lung cancer. Mutual phosphorylation of FAK and Src is involved in osimertinib resistance. Thus, FAK and Src inhibition may be novel treatment strategies for osimertinib-resistant NSCLC.