Crizotinib sensitizes the erlotinib resistant HCC827GR5 cell line by influencing lysosomal function

Nele Van Der Steen, Kaylee Keller, Henk Dekker, Letizia Porcelli, Richard J. Honeywell, Johan Van Meerloo, René J.P. Musters, Ietje Kathmann, Adam E. Frampton, Daniel S.K. Liu, Rob Ruijtenbeek, Christian Rolfo, Patrick Pauwels, Elisa Giovannetti*, Godefridus J. Peters

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

In non-small cell lung cancer, sensitizing mutations in epidermal growth factor receptor (EGFR) or cMET amplification serve as good biomarkers for targeted therapies against EGFR or cMET, respectively. Here we aimed to determine how this different genetic background would affect the interaction between the EGFR-inhibitor erlotinib and the cMET-inhibitor crizotinib. To unravel the mechanism of synergy we investigated the effect of the drugs on various parameters, including cell cycle arrest, migration, protein phosphorylation, kinase activity, the expression of drug efflux pumps, intracellular drug concentrations, and live-cell microscopy. We observed additive effects in EBC-1, H1975, and HCC827, and a strong synergism in the HCC827GR5 cell line. This cell line is a clone of the HCC827 cells that harbor an EGFR exon 19 deletion and has been made resistant to the EGFR-inhibitor gefitinib, resulting in cMET amplification. Remarkably, the intracellular concentration of crizotinib was significantly higher in HCC827GR5 compared to the parental HCC827 cell line. Furthermore, live-cell microscopy with a pH-sensitive probe showed a differential reaction of the pH in the cytoplasm and the lysosomes after drug treatment in the HCC827GR5 in comparison with the HCC827 cells. This change in pH could influence the process of lysosomal sequestration of drugs. These results led us to the conclusion that lysosomal sequestration is involved in the strong synergistic reaction of the HCC827GR5 cell line to crizotinib–erlotinib combination. This finding warrants future clinical studies to evaluate whether genetic background and lysosomal sequestration could guide tailored therapeutic interventions.

Original languageEnglish
Number of pages13
JournalJournal of Cellular Physiology
Volume235
Issue number11
DOIs
Publication statusE-pub ahead of print - 1 Jan 2020

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