Abstract 3641: The DNA repair protein hABH2 mediates temozolomide resistance in human glioblastoma cells

Abstract

Listen

Translate article

Abstract Background and Purpose: Glioblastoma multiforme is the most malignant and frequent primary brain tumour in adults. Current treatment remains insufficient as these tumours display a diffuse infiltrative growth pattern and tend to recur despite extensive debulking surgery followed by radio- and chemotherapy. The methylating agent temozolomide is at present the cornerstone of glioblastoma chemotherapy. However, several independent DNA repair mechanisms can restore the integrity of methylated DNA bases, and thus contribute to temozolomide resistance and subsequent therapy failure. In this work we examined whether human AlkB homologue 2 (hABH2), an oxidative demethylase capable of reversing methyl lesions in DNA, might provoke temozolomide resistance in human glioblastoma cells. Materials and Methods: hABH2 expression was examined in eight established glioma cell lines as well as normal human brain using quantitative real-time PCR. Cells derived from a hABH2 deficient glioblastoma were transfected with a hABH2 plasmid prior to antibiotic selection, and subsequent colonies were screened for hABH2 expression by western blotting. Temozolomide sensitivity was assessed for hABH2 proficient and deficient colonies using a tetrazolium salt assay after 96 hours of drug incubation. Results: mRNA levels of hABH2 were generally 2-4 fold higher in the established cell lines compared to normal human brain. Furthermore, hABH2 overexpressing glioblastoma cells were significantly more resistant to temozolomide than hABH2 deficient cells derived from the same patient. Conclusions: Our results show that hABH2 is expressed at high levels in glioma cells, and that overexpression of this protein mediates temozolomide resistance in vitro. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. 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 3641.