IGF1R depletion facilitates MET-amplification as mechanism of acquired resistance to erlotinib in HCC827 NSCLC cells

Dianna Hussmann,Anders Lade Nielsen,Boe Sandahl Sorensen,Anne Tranberg Madsen,Yonglun Luo,Kristine Raaby Jakobsen

doi:10.18632/oncotarget.16350

Dianna Hussmann, Anders Lade Nielsen + Show 4 more

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https://doi.org/10.18632/oncotarget.16350

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Journal: Oncotarget	Publication Date: Mar 18, 2017
Citations: 22	License type: cc-by

Affiliation: Aarhus University, Aarhus University Hospital

Abstract

EGFR-mutated non-small cell lung cancer patients experience relapse within 1-2 years of treatment with EGFR-inhibitors, such as erlotinib. Multiple resistance mechanisms have been identified including secondary EGFR-mutations, MET-amplification, and epithelial-mesenchymal transition (EMT). Previous studies have indicated a role of Insulin-like growth factor 1 receptor (IGF1R) in acquired resistance to EGFR-directed drugs as well as in EMT. In the present study, we have investigated the involvement of IGF1R in acquired high-dose erlotinib resistance in the EGFR-mutated lung adenocarcinoma cell line HCC827. We observed that IGF1R was upregulated in the immediate response to erlotinib and hyperactivated in erlotinib resistant HCC827 cells. Resistant cells additionally acquired features of EMT, whereas MET-amplification and secondary EGFR-mutations were absent. Using CRISPR/Cas9, we generated a HCC827(IGFR1−/−) cell line and subsequently investigated resistance development in response to high-dose erlotinib. Interestingly, HCC827(IGFR1−/−) cells were now observed to specifically amplify the MET gene. Additionally, we observed a reduced level of mesenchymal markers in HCC827(IGFR1−/−) indicating an intrinsic enhanced epithelial signature compared to HCC827 cells. In conclusion, our data show that IGF1R have an important role in defining selected resistance mechanisms in response to high doses of erlotinib.

Highlights

Acquired resistance to targeted therapies remains a major challenge in lung cancer treatment
Acquired erlotinib resistance in HCC827 is associated with increased insulin-like growth factor 1 receptor (IGF1R) expression and receptor hyperactivation
As IGF1R was not necessary for maintaining an already gained erlotinib resistance in HCC827ER cells, we speculated whether IGF1R signaling was important for initiating epithelial-mesenchymal transition (EMT) during the early steps of resistance development

Summary

Introduction

Acquired resistance to targeted therapies remains a major challenge in lung cancer treatment. Non-small cell lung cancer (NSCLC) patients with tumors harboring EGFR-activating mutations highly benefit from EGFR-directed treatment [1, 2]. High IGF1R expression was significantly associated with inferior progression-free survival (PFS) in tumors harboring EGFR activating mutations. This was supported by the findings of Yeo et al reporting IGF1R protein expression as a negative predictor of response to EGFR-directed treatment in EGFR-mutated NSCLC patients [27]. A study by Morgillo et al found EMT features and increased IGF1R activation in TKI-resistant cell lines, but IGF1R inhibition had no significant effect on the viability of resistant cells [20]. Using CRISPR/ Cas mediated gene editing we induce a deletion within the IGF1R gene and analyze the mechanisms of resistance development in response to high-dose erlotinib treatment

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