Integrative analysis identifies a novel AXL-PI3 kinase-PD-L1 signaling axis associated with radiation resistance in head and neck cancer

Heath D. Skinner, Uma Giri, Liang P. Yang, Manish Kumar, Ying Liu, Michael D. Story, Curtis R. Pickering, Lauren A. Byers, Michelle D. Williams, Jing Wang, Li Shen, Suk Y. Yoo, You Hong Fan, David P. Molkentine, Beth M. Beadle, Raymond E. Meyn, Jeffrey N. Myers, John V. Heymach

Research output: Contribution to journalArticlepeer-review

72 Scopus citations


Purpose: The primary cause of death due to head and neck squamous cell carcinoma (HNSCC) is local treatment failure. The goal of this study was to examine this phenomenon using an unbiased approach. Experimental Design: We utilized human papilloma virus (HPV)-negative cell lines rendered radiation-resistant (RR) via repeated exposure to radiation, a panel of HPV-negative HNSCC cell lines and three cohorts of HPV-negative HNSCC tumors (n = 68, 97, and 114) from patients treated with radiotherapy and subjected to genomic, transcriptomic, and proteomic analysis. Results: RR cell lines exhibited upregulation of several proteins compared with controls, including increased activation of Axl and PI3 kinase signaling as well as increased expression of PD-L1. Additionally, inhibition of either Axl or PI3 kinase led to decreased PD-L1 expression. When clinical samples were subjected to RPPA and mRNA expression analysis, PD-L1 was correlated with both Axl and PI3K signaling as well as dramatically associated with local failure following radiotherapy. This finding was confirmed examining a third cohort usingimmunohistochemistry. Indeed, tumors with high expression of PD-L1 had failure rates following radiotherapy of 60%, 70%, and 50% compared with 20%, 25%, and 20% in the PD-L1-low expression group (P = 0.01, 1.9 × 10-3, and 9 × 10-4, respectively). This finding remained significant on multivariate analysis in all groups. Additionally, patients with PDL1 low/CD8+ tumor-infiltrating lymphocytes high had no local failure or death due to disease (P = 5 × 10-4 and P = 4 × 10-4, respectively). Conclusions: Taken together, our data point to a targetable Axl-PI3 kinase-PD-L1 axis that is highly associated with radiation resistance.

Original languageEnglish (US)
Pages (from-to)2713-2722
Number of pages10
JournalClinical Cancer Research
Issue number11
StatePublished - Jun 1 2017

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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