Abstract 587: Development of brain tumor-specific targeted system by using retroviral-mediated gene therapy with SSX4 promoter

• Published in: Cancer research (Chicago, Ill.) Ill.), 2010-04, Vol.70 (8_Supplement), p.587-587
• Main Authors: Shimizu, Keiji, Ishida, Eri, Kitahara, Masahiro, Tamura, Masakazu, Yawata, Toshio
• Format: Article
• Language: English
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/1538-7445.AM10-587

Despite many efforts to develop effective therapy, the outcome of malignant glioma remains poor. Previously, we reported the eradication of mouse glioma by retroviral-mediated gene therapy. In this study, a tumor-specific targeting system was studied to develop the effective and safe gene therapy. We first searched for genes expressing at high frequency in brain tumors but not in normal human astrocyte (NHA) among cancer testis antigen (CTA) genes by in silico and RT-PCR screening. MAGEA3 and SSX4 were identified as tumor-specific genes. The promoter activity was measured in glioma, telomerase-immortalized fibroblast and NHA cells. The SSX4 promoter but not MAGEA3 showed the tumor-specific activity. In order to define a useful tumor-specific promoter for targeting in context of retroviral-mediated gene therapy, the SSX4 promoter were used to restrict the expression of suicide gene HSVtk in retroviral vector. The glioma cell lines transduced with the retroviral vector were killed efficiently by addition of ganciclovir (GCV), but telomerase-immortalized fibroblast BJ-5ta cells were not. Mouse glioma RSV-M cells transduced with the retroviral vector were transplanted into S.C. of syngeneic mouse. The administration of GCV suppressed the tumor growth completely. These results suggest that trans-acting factors may play a role for tumor-specific activity of SSX4 promoter while the expression of most CTA genes is regulated by epigenetic factors and the retrovirus vector expressing HSVtk under control of SSX4 promoter is a promising therapeutic reagent for malignant brain tumors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 587.