A chemical genetic screen identifies Aurora kinases as a therapeutic target in EGFR T790M negative, gefitinib-resistant head and neck squamous cell carcinoma (HNSCC)

Abstract

Background: Overexpression of epidermal growth factor receptor (EGFR), and downstream pathway activation appears to be a common oncogenic driver in the majority of head and neck squamous cell cancers (HNSCCs); yet targeting EGFR for the treatment of HNSCC has met with limited success. Apart from the anti-EGFR antibody cetuximab, no small molecule EGFR/tyrosine kinase inhibitors (TKIs) have progressed to routine clinical use. The aim of this study was to determine factors contributing to the lack of response to TKIs and identify alternative therapeutic vulnerabilities. Methods: Genomic and transcriptomic sequencing, high-throughput compound screens, overexpression and siRNA knockdown, western blot, in vivo xenograft studies. Findings: We derived three pairs of isogenic gefitinib (TKI)-sensitive and resistant patient-derived HNSCC cell lines. Genomic sequencing of gefitinib-resistant cell lines identified a lack of activating and resistance-associated EGFR mutations. Instead, transcriptomic sequencing showed upregulated EMT gene signature in the gefitinib-resistant cells with a corresponding increase in their migratory phenotype. Additionally, the resistant cell displayed reduced growth rate. Surprisingly, while gefitinib-resistant cells were independent of EGFR for survival, they nonetheless displayed activation of downstream ERK and AKT signalling. Highthroughput screening (HTS) of druggable, small molecule libraries revealed that the gefitinib-resistant cells were particularly sensitive to inhibitors of genes involved in cell cycle and mitosis, such as Aurora kinase inhibitors (AKIs), cyclin-dependent kinase (CDK) inhibitors, and microtubule inhibitors. Notably our results showed that in the EGFR inhibited state, Aurora kinases are essential for cell survival. Interpretation: Our study demonstrates that in the absence of activating EGFR mutations, HNSCCs may gain resistance to gefitinib through decreased cell proliferation, which makes them exceptionally vulnerable to cell-cycle inhibitors.

EGFR and PI3K Pathway Activities Might Guide Drug Repurposing in HPV-Negative Head and Neck Cancers

“…TAK-901 is an Aurora kinase inhibitor. Aurora kinases have recently been identified as therapeutic targets in EGFRnegative, gefitinib-resistant HNSCC cell lines (44). Intriguingly, Aurora kinase A (AURKA) has been shown to limit PI3Kpathway inhibition in a breast cancer model suggesting a dependent signaling network (45).…”

Aurora Kinases as Therapeutic Targets in Head and Neck Cancer

“…4B), thereby contributing to ability of these tumors to survive treatment with EGFR inhibitors; this study showed that AURKA inhibitors synergize with EGFR inhibitors to eliminate EGFR-resistant cells in vitro and in vivo. 99 Aurora inhibitors have been identified as cytotoxic in patient-derived HNSCC cell lines that were both sensitive and resistant to the EGFR inhibitor gefitinib; in this study, resistant cells had wild-type EGFR with increased levels of phosphorylated AURKA 130 . Such results suggest means to apply AURKA inhibitors in combination therapies, as discussed below.…”

Single cell analysis in head and neck cancer reveals potential immune evasion mechanisms during early metastasis

“…Rather than impacting the metastatic process, it is possible that this vulnerability reflects a generalized reduction in cell cycling that occurs during EMT with a concomitant sensitivity to all cell cycle inhibitors. We recently demonstrated the same phenomenon during drug resistance: reduction in cell proliferation, limited AURK expression and sensitivity to inhibitors of AURK and other cell cycle targets 41 . Nevertheless, the ability to profile tumors and identify vulnerabilities in metastasis-inducing clones is an attractive notion, with increasing interest in low-dose, long term anti-metastatic therapy.…”