Background: The purpose of this study was to investigate the effects of combining the phosphotidylinositol-3-kinase (PI3K) inhibitor buparlisib (BKM)120 with the anti-epidermal growth factor receptor (EGFR) agent cetuximab and radiotherapy (RT) on an orthotopic model of head and neck squamous cell carcinoma (HNSCC).
Methods: We evaluated the antitumor efficacy of BKM120, cetuximab, and RT, administered alone or in combination, using the human PIK3CA-mutated HNSCC cell line, CAL33, injected into the floor of the mouth of nude mice.
Results: Compared with control, the BKM120-cetuximab and the BKM120-cetuximab-RT combinations led to the highest tumor inhibition (p < .001). The highest inhibitory effect of treatments on cell proliferation, mitogen-activated protein kinase (MAPK) and PI3K/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathways were found with the BKM120-cetuximab association. The association of BKM120 and cetuximab with RT inhibited RT-induced activation of the MAPK pathway.
Conclusion: These results can serve as a preclinical rationale for innovative treatments combining PI3K inhibition with anti-EGFR therapies and irradiation in patients with HNSCC. © 2016 Wiley Periodicals, Inc. Head Neck 39: 151-159, 2017.
Keywords: epidermal growth factor receptor (EGFR); head and neck cancer; phosphatidylinositol 3-kinase (PIK3CA); radiotherapy; targeted therapy.
© 2016 Wiley Periodicals, Inc.