1
|
Kadi NE, Wang L, Davis A, Cooke A, Vadnala V, Korkaya H, Kalemkerian GP, Hassan KA. Abstract 931: The T790M mutation is acquired through 5-methylcytosine deamination after EGFR TKI treatment in lung cancer. Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Epidermal growth factor receptor (EGFR) activation mutations occur in 10-50% of lung adenocarcinomas. EGFR tyrosine kinase inhibitors (TKIs) are the mainstay of treatment for stage IV non-small cell lung cancer (NSCLC) patients with EGFR mutations. However, acquired EGFR mutations are the main mechanism of on-target resistance to TKIs. T790M mutation that occurs after first generation TKI treatment, is a cytosine to thymine (C>T) single nucleotide transition leading to a threonine to methionine amino acid change at position 790 (i.e. T790M). Our data suggest that resistant mutations are acquired events secondary to cytosine deamination through Activation Induced Cytosine Deamination enzyme (AICDA). Interestingly, treatment with Osimertinib, that overcomes the T790M mutation, leads to other acquired resistant mutations (C797S, G796S/R and L792F/H) that are mostly cytosine based.
Results: Sub clones of the lung adenocarcinoma cell line PC9 with no evidence of T790M mutation by digital droplet PCR (ddPCR) at baseline, were treated with EGFR TKI. After serially increasing the treatment dose, T790M mutation was detected by ddPCR associated with a significant increase in AICDA expression. Similarly, when the resistant T790M PC9 clones were treated with Osimertinib, the expression of AICDA was also induced. Knocking down AICDA by shRNA or CRISPR-Cas9, decreases the development of T790M in PC9 cell lines after TKI exposure. Using mass spectrometry, we established that cytosine at codon 790 is methylated; thus, deamination of 5-methylcytosine leads to thymine directly, explaining the T790M C>T mutation. In addition, using ChIP assay and pharmacological inhibition we confirm that upon TKI exposure, NFκB binds AICDA promoter and induces its expression. In a mouse xenograft model, the induction of NFκB and AICDA after EGFR TKI exposure is abrogated by concurrent use of an NFκB inhibitor. Finally, patients treated with EFR TKI had an increased expression of AICDA upon progression.
Conclusion: In EGFR driven lung adenocarcinoma, NFκB pathway is activated upon exposure to EGFR TKIs which induces AICDA expression. AICDA deaminates cytosine into other nucleotides leading to treatment resistance.
Citation Format: Najwa El Kadi, Luo Wang, April Davis, Alexander Cooke, Varun Vadnala, Hasan Korkaya, Gregory P. Kalemkerian, Khaled A. Hassan. The T790M mutation is acquired through 5-methylcytosine deamination after EGFR TKI treatment in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 931.
Collapse
Affiliation(s)
| | - Luo Wang
- 1University of Michigan, Ann Arbor, MI
| | | | | | | | | | | | | |
Collapse
|
2
|
El Kadi N, Wang L, Davis A, Korkaya H, Cooke A, Vadnala V, Brown NA, Betz BL, Cascalho M, Kalemkerian GP, Hassan KA. The EGFR T790M Mutation Is Acquired through AICDA-Mediated Deamination of 5-Methylcytosine following TKI Treatment in Lung Cancer. Cancer Res 2018; 78:6728-6735. [PMID: 30333118 DOI: 10.1158/0008-5472.can-17-3370] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 08/17/2018] [Accepted: 10/09/2018] [Indexed: 12/30/2022]
Abstract
: Almost all patients with EGFR-driven lung cancer who are treated with EGFR tyrosine kinase inhibitors (TKI) develop resistance to treatment. A single base (c.2369C>T) transition mutation, EGFR T790M, is the most frequent resistance event after first-generation exposure to EGFR TKIs. Whether T790M mutation is acquired or is selected from a preexisting clone has been a matter of significant debate. In this study, we show that treatment with EGFR TKIs leads to activation of the NFκB pathway, which in turn induces expression of activation-induced cytidine deaminase (AICDA). In turn, AICDA causes deamination of 5-methylcytosine to thymine at position c.2369 to generate the T790M mutation. Pharmacologic inhibition of the NFκB pathway or knockout of AICDA decreased the frequency or prevented the development of T790M mutation, respectively. In addition, patients treated with first-line EGFR TKI displayed increased expression of AICDA and detection of the T790M mutation upon progression. These results identify the mechanism of T790M acquisition and present an opportunity to target the process to delay or prevent it. SIGNIFICANCE: These findings identify the mechanism behind acquisition of a common resistance mutation to TKI treatment in lung cancer.
Collapse
Affiliation(s)
- Najwa El Kadi
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Luo Wang
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - April Davis
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | | | - Alexander Cooke
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Varun Vadnala
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Noah A Brown
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Bryan L Betz
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Marilia Cascalho
- Department of Surgery (MIC), University of Michigan, Ann Arbor, Michigan
| | | | - Khaled A Hassan
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
| |
Collapse
|