Cancer Therapy: Preclinical Humanized Anti-Interleukin-6 Receptor Antibody Suppresses Tumor Angiogenesis and In vivo Growth of Human Oral Squamous Cell Carcinoma

Purpose: The biological effect of interleukin-6 (IL-6) signaling in oral squamous cell carcinoma (OSCC) and whether IL-6 receptor (IL-6R)-mediated signaling can be a therapeutic target for OSCC are unclear. The aim of this study was to investigate the effects of inhibition of IL-6R–mediated signaling on OSCC progression and to evaluate the availability of tocilizumab, a humanized antihuman IL-6R antibody, as a therapeutic agent for OSCC. Experimental Design: We evaluated expression levels of IL-6 and IL-6R in 58 OSCC tissues and 4 OSCC cell lines by real-time quantitative reverse transcription-PCR and/ or immunohistochemstry. We investigated the effects of tocilizumab on OSCC growth in vitro and in xenografts. Xenografts were analyzed by immunohistochemistry for phosphorylated signal transducer and activator of transcription 3 (pSTAT3), Ki-67, and CD31, and terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling assay was done. Results: Expression levels of IL-6 at both mRNA and protein levels in OSCC tissues were significantly higher than those in normal mucosal tissues. In addition, OSCC cell lines expressed higher levels of both IL-6 and IL-6R mRNA than did HaCaT keratinocytes. Tocilizumab significantly reduced in vivo growth of SAS cells with a drastic reduction of STAT3 phosphorylation in tumor cells in mice. Inhibition of IL-6 signaling significantly decreased vascular endothelial growth factor mRNA expression in SAS, and microvessel density and vessel diameter in SAS tumors in tocilizumab-treated mice. Conclusions: Therapeutic approaches targeting IL-6R by tocilizumabmay be effective for OSCC treatment by at least inhibiting angiogenesis. (Clin Cancer Res 2009;15(17):5426–34) Oral cancer, predominantly oral squamous cell carcinoma (OSCC), is the most common head and neck neoplasm, affecting about 270,000 people worldwide in 2002 (1). In Japan, OSCC is relatively common, accounting for >5,500 deaths in 2003 (2). Despite advances in early detection, diagnosis, and treatment of head and neck squamous cell carcinoma (HNSCC), the 5-year survival for patients with HNSCC has remained at 50% for the past 30 years (3). Appropriate treatment of HNSCC remains one of the most difficult challenges in head and neck oncology. Surgical therapy can be mutilating and often has significant effects on swallowing, speech, and physical appearance. The additional chemotherapy to radiation treatment has shown efficacy in organ preservation in some sites in the head and neck, but has resulted in limited improvement in survival rates. The aforementioned facts underscore the need for the development of a novel therapeutic approach for patients with HNSCC. It has been well documented that cancer can be promoted and/or exacerbated by inflammation and infections (4). Important components in this linkage are the cytokines produced by tumor cells as well as activated innate immune cells (4). One avenue that holds promise is modulation of the expression and the signal of proinflammatory and proangiogenic cytokines (4, 5). Interleukin-6 (IL-6) is a multifunctional cytokine that was originally characterized as a regulator of immune and inflammatory responses (6). Elevated expression of IL-6 has been detected in multiple tumors (6). Multiple studies have Authors' Affiliations: Departments of Oral and Maxillofacial Surgery, Diagnostic Medicine, Neurosurgery, Molecular Genetics, and Breast and Endocrine Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan Received 2/5/09; revised 6/11/09; accepted 6/15/09; published OnlineFirst 8/25/09. Grant support: The authors' work was supported by Grants-in-Aid for Scientific Research (B) 17390254 (Y. Ando) and (B) 17390541 (M. Shinohara) from the Ministry of Education, Science, Sports and Culture of Japan. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Requests for reprints: Yukio Ando, Department of Diagnostic Medicine, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-0811, Japan. Phone: 81-96-373-5686; Fax: 81-96-373-5686; E-mail: [email protected]. F 2009 American Association for Cancer Research. doi:10.1158/1078-0432.CCR-09-0287 5426 Clin Cancer Res 2009;15(17) September 1, 2009 www.aacrjournals.org Research. on April 14, 2017. © 2009 American Association for Cancer clincancerres.aacrjournals.org Downloaded from Published OnlineFirst August 25, 2009; DOI: 10.1158/1078-0432.CCR-09-0287