Survival of head and neck cancer cells relies upon LZK kinase- mediated stabilization of mutant p53

Head and neck squamous cell carcinoma (HNSCC) includes epithelial cancers of the oral and nasal cavity, larynx, and pharynx and accounts for ~350,000 deaths/year worldwide. Smoking- related HNSCC is associated with few targetable mutations but is defined by frequent copy number alteration, the most common of which is gain at 3q. Critical 3q target genes have not been conclusively determined for HNSCC. Here we present data indicating that MAP3K13 (encoding LZK) is an amplified driver gene in HNSCC. Copy number gain at 3q resulted in increased MAP3K13 mRNA in HNSCC tumor samples and cell lines. Silencing LZK reduced cell viability and proliferation of HNSCC cells with 3q gain but not control cell lines. Inducible silencing of LZK caused near complete loss of colony-forming ability in cells harboring 3q gain. These results were validated in vivo by evidence that LZK silencing was sufficient to reduce tumor growth in a xenograft model of HNSCC. Our results establish LZK as critical for maintaining expression of mutant stabilized p53.