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Mol Cancer Ther. 2014 Sep;13(9):2203-14. doi: 10.1158/1535-7163.MCT-14-0013. Epub 2014 Jul 15.

Quinacrine overcomes resistance to erlotinib by inhibiting FACT, NF-κB, and cell-cycle progression in non-small cell lung cancer.

Author information

1
Department of Molecular Genetics, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio.
2
Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, New York.
3
Division of General Medical Sciences-Oncology, Case Comprehensive Cancer Center, Cleveland, Ohio.
4
Case Comprehensive Cancer Center, University Hospitals Seidman Cancer Center, Case Western Reserve University, Cleveland, Ohio.
5
Department of Medicine, Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, Ohio.
6
Case Comprehensive Cancer Center, University Hospitals Seidman Cancer Center, Case Western Reserve University, Cleveland, Ohio. starkg@ccf.org Neelesh.Sharma@UHhospitals.org.
7
Department of Molecular Genetics, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio. starkg@ccf.org Neelesh.Sharma@UHhospitals.org.

Abstract

Erlotinib is a tyrosine kinase inhibitor approved for the treatment of patients with advanced non-small cell lung cancer (NSCLC). In these patients, erlotinib prolongs survival but its benefit remains modest because many tumors express wild-type (wt) EGFR or develop a second-site EGFR mutation. To test drug combinations that could improve the efficacy of erlotinib, we combined erlotinib with quinacrine, which inhibits the FACT (facilitates chromatin transcription) complex that is required for NF-κB transcriptional activity. In A549 (wtEGFR), H1975 (EGFR-L858R/T790M), and H1993 (MET amplification) NSCLC cells, this drug combination was highly synergistic, as quantified by Chou-Talalay combination indices, and slowed xenograft tumor growth. At a sub-IC50 but more clinically attainable concentration of erlotinib, quinacrine, alone or in combination with erlotinib, significantly inhibited colony formation and induced cell-cycle arrest and apoptosis. Quinacrine decreased the level of active FACT subunit SSRP1 and suppressed NF-κB-dependent luciferase activity. Knockdown of SSRP1 decreased cell growth and sensitized cells to erlotinib. Moreover, transcriptomic profiling showed that quinacrine or combination treatment significantly affected cell-cycle-related genes that contain binding sites for transcription factors that regulate SSRP1 target genes. As potential biomarkers of drug combination efficacy, we identified genes that were more strongly suppressed by the combination than by single treatment, and whose increased expression predicted poorer survival in patients with lung adenocarcinoma. This preclinical study shows that quinacrine overcomes erlotinib resistance by inhibiting FACT and cell-cycle progression, and supports a clinical trial testing erlotinib alone versus this combination in advanced NSCLC.

PMID:
25028470
PMCID:
PMC4156551
DOI:
10.1158/1535-7163.MCT-14-0013
[Indexed for MEDLINE]
Free PMC Article

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