Functional Kinomics Identifies Candidate Therapeutic Targets in Head and Neck Cancer

Abstract

Purpose To identify novel therapeutic drug targets for p53 mutant head and neck squamous cell carcinoma (HNSCC). Experimental Design RNAi kinome viability screens were performed on HNSCC cells including autologous pairs from primary tumor and recurrent/metastatic lesions, and in parallel on murine squamous cell carcinoma (MSCC) cells derived from tumors of inbred mice bearing germline mutations in Trp53, and p53 regulatory genes: Atm, Prkdc, and p19Arf. Cross-species analysis of cell lines stratified by p53 mutational status and metastatic phenotype was utilized to select 38 kinase targets. Both primary and secondary RNAi validation assays were performed on additional HNSCC cell lines to credential these kinase targets utilizing multiple phenotypic endpoints. Kinase targets were also examined via chemical inhibition utilizing a panel of kinase inhibitors. A preclinical study was conducted on the WEE1 kinase inhibitor, MK-1775. Results Our functional kinomics approach identified novel survival kinases in HNSCC involved in G2/M cell cycle checkpoint, SFK, PI3K and FAK pathways. RNAi mediated knockdown and chemical inhibition of the WEE1 kinase with a specific inhibitor, MK-1775, had a significant effect on both viability and apoptosis. Sensitivity to the MK-1775 kinase inhibitor is in part determined by p53 mutational status, and due to unscheduled mitotic entry. MK-1775 displays single-agent activity and potentiates the efficacy of cisplatin in a p53 mutant HNSCC xenograft model. Conclusions WEE1 kinase is a potential therapeutic drug target for HNSCC. This study supports the application of a functional kinomics strategy to identify novel therapeutic targets for cancer.

Wee-1 Kinase Inhibition Overcomes Cisplatin Resistance Associated with High-RiskTP53Mutations in Head and Neck Cancer through Mitotic Arrest Followed by Senescence

“…Recent report has also shown that Wee-1 kinase inhibition with high doses of MK-1775 leads to unscheduled mitotic entry associated with apoptosis in p53 mutant HNSCC cells (35). In our study, neither PARP-1 cleavage nor APO-BrdU tunnel staining was detected in our isogenic cell HNSCC lines with combination therapy, confirming no engagement of apoptosis.…”

“…Moser and colleagues have recently shown that MK-1775 potentiates cisplatin response in mice bearing mutant p53 HNSCC cells established as subcutaneous flanks; however, they have not examined efficacy of MK-1775 in oral tongue xenografts (35). Ectopic subcutaneous xenograft models have proven less useful for studying therapeutic agents than orthotopic models that recapitulate the tumor microenvironment (30).…”

Emerging biomarkers in head and neck cancer in the era of genomics

“…132 In particular, WEE1 (a G2-M cell-cycle regulator) can render synthetic lethality in TP53-mutant tumours because cells without functional p53 lack an effective G1 checkpoint and rely heavily on the G2 checkpoint regulators, such as WEE1, resulting in increased sensitivity of TP53-mutant cells to WEE1 inhibitors. Thus, TP53 mutations with functional consequences need to be revisited as prognostic and p redictive b iomarkers in HNSCC.…”

Wee-1 Kinase Inhibition Sensitizes High-Risk HPV+ HNSCC to Apoptosis Accompanied by Downregulation of MCl-1 and XIAP Antiapoptotic Proteins

“…Therefore, inhibition of the Wee-1 kinase activity can override a G2 cell cycle arrest and/or result in DNA damage by disrupting replication of the genome, leading to premature accumulation of cells with extensive DNA damage in mitosis and subsequent cell death through mitotic catastrophe (13, 14). Recent work with AZD-1775 (formerly known as MK-1775), a specific inhibitor of Wee-1, and siRNA-mediated depletion indicates that Wee-1 inhibition abrogates the G2 checkpoint and selectively sensitizes tumor cells defective of p53 to various DNA-damaging agents, such as gemcitabine, cisplatin, and inhibits tumor growth in in vivo models (15-18). In light of the findings from these preclinical studies, AZD-1775 has entered phase I and II clinical trials as a chemosensitizer in patients with advanced solid tumors and shows good tolerability with minimal collateral cytotoxicity.…”