Abstract 4889: Alteration of cancer stem cell-like phenotype by histone deacetylase inhibitors in squamous cell carcinoma of the head and neck.

Abstract

Abstract Recent progression in the understanding of stem cell biology has greatly facilitated the identification and characterization of cancer stem cells (CSCs) from various tumors. In squamous cell carcinoma of the head and neck (SCCHN), various cell surface markers, including CD44, CD133 and ALDH1, have been identified as the potential markers to isolate CSCs. Evidence has accumulated indicating that conventional cancer treatments are potentially ineffective against CSCs. Histone deacetylase inhibitors (HDACi) have multiple biologic effects consequent to alteration in patterns of acetylation of histones and are promising new group of anticancer agents. In this study, we investigate the effects of two HDACi, suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA) on two CD44+ cancer stem-like cell lines from SCCHN cultured in serum-free medium containing epidermal growth factor and basic fibroblast growth factor. SAHA and TSA inhibited the growth of SCCHN cell lines in a dose dependent manner as measured by MTS assays. Moreover, SAHA and TSA induced G2/M cell cycle arrest and apoptosis in these SCCHN cell lines. Interestingly, the expression of cancer stem cell markers, CD44 and ABCG2 on SCCHN cell lines were decreased by SAHA or TSA treatment. HDACi also decreased the mRNA expression levels of stemness-related genes (Notch and Nanog) and TGF-β. As expected, HDACi markedly increased the expression of E-cadherin. In addition, the combination of HDACi and chemotherapeutic agents, including cisplatin and docetaxel had a synergistic effect on SCCHN cell lines. Taken together, our data indicate that HDACi not only inhibit the growth of SCCHN cell lines by inducing apoptosis and cell cycle arrest, but also alter stem-like properties of the SCCHN cells, raising the possibility that HDACi may have therapeutic potentials for cancer stem cells of SCCHN. Citation Format: Koichi Sakakura, Takaaki Murata, Kazuaki Chikamatsu. Alteration of cancer stem cell-like phenotype by histone deacetylase inhibitors in squamous cell carcinoma of the head and neck. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4889. doi:10.1158/1538-7445.AM2013-4889