Antitumor activity of enzastaurin as radiation sensitizer in head and neck squamous cell carcinoma

Abstract

Background: The antitumor effect of enzastaurin, a specific protein kinase C beta (PKC-β) inhibitor, was tested on head and neck squamous cell carcinoma (HNSCC) cell lines, as well as HNSCC xenograft model.

Methods: HNSCC cell lines and xenograft were treated with enzastaurin alone or in combination with radiation to evaluate its antitumor effect. Annexin V-FITC staining and Western blot were done to analyze enzastaurin-induced changes in apoptosis and the PIK3/AKTAKT signal transduction pathway.

Results: Enzastaurin showed strong antitumor activity either alone or in combination with radiation both in HNSCC cell lines and in xenograft, with a corresponding reduction in the expression of key radioresponsive proteins.

Conclusion: Enzastaurin can inhibit tumor growth and improve the efficacy of radiation for HNSCC both in vitro and in vivo. This suggests that enzastaurin may represent a better strategy for the treatment of HNSCC patients, either as a monotherapy or as a radiosensitizer.