Expression and correlation of Bcl-2 with pathological grades in human glioma stem cells

Abstract

The anti-apoptotic gene, B-cell lymphoma-2 (Bcl-2), has been reported to be overexpressed in gliomas and is related to tumor prognosis, suggesting a potential therapeutic target. Additionally, recent studies have demonstrated the existence of brain glioma stem cells (BGSCs) which are tumorigenic, self-renewable and dominate the biological behavior of gliomas. Currently BGSCs are committed as a new target of glioma therapies. However, few studies have focused on the expression of Bcl-2 in BGSCs. We performed a series of experiments to culture BGSCs from eight clinical specimens, followed by real-time RT-PCR and immunoassays to compare the expression levels of Bcl-2 in BGSCs and their corresponding primary glioma cells (PGCs). The results showed that Bcl-2 mRNA and protein expression levels are higher in BGSCs compared to their counterparts, and the expression levels are related to glioma malignancies. As an anti-apoptotic gene, Bcl-2 assigns immortality characteristics to cells, which coincide with the pivotal biological feature of BGSCs. The experimental results indicated that BGSCs would evade apoptosis for higher Bcl-2 expression, and may interpret the drug resistance of glioma to cytotoxic drugs and other pro-apoptotic agents. New therapies targeting Bcl-2 must induce apoptosis in BGSCs, thus, resulting in treatment or even eradication of glioma.