Berghauser Pont Lotte M E, Spoor Jochem K H, Venkatesan Subramanian, Swagemakers Sigrid, Kloezeman Jenneke J, Dirven Clemens M F, van der Spek Peter J, Lamfers Martine L M, Leenstra Sieger
Department of Neurosurgery, Brain Tumor Center, Erasmus MC, Rotterdam, The Netherlands.
Department of Bio-informatics, Erasmus MC, Rotterdam, The Netherlands.
Genes Cancer. 2014 Nov;5(11-12):445-59. doi: 10.18632/genesandcancer.42.
Glioblastoma has shown resistance to histone deacetylase inhibitors (HDACi) as radiosensitizers in cultures with Bcl-XL over-expression. We study the efficacy of SAHA/RTx and LBH589/RTx when manipulating Bcl-2 family proteins using the Bcl-2 inhibitor Obatoclax in patient-derived glioblastoma stem-like cell (GSC) cultures. GSC cultures in general have a deletion in phosphatase and tensin homolog (PTEN). Synergy was determined by the Chou Talalay method. The effects on apoptosis and autophagy were studied by measuring caspase-3/7, Bcl-XL, Mcl-1 and LC3BI/II proteins. The relation between treatment response and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status, recurrence and gene expression levels of the tumors were studied. Obatoclax synergized with SAHA and LBH589 and sensitized cells to HDACi/RTx. Over 50% of GSC cultures were responsive to Obatoclax with either single agent. Combined with HDACi/RTx treatment, Obatoclax increased caspase-3/7 and inhibited Bcl-2 family proteins Bcl-XL and Mcl-1 more effectively than other treatments. Genes predictive for treatment response were identified, including the F-box/WD repeat-containing protein-7, which was previously related to Bcl-2 inhibition and HDACi sensitivity. We emphasize the functional relation between Bcl-2 proteins and radiosensitization by HDACi and provide a target for increasing responsiveness in glioblastoma by using the Bcl-2 inhibitor Obatoclax.
在Bcl-XL过表达的培养物中，胶质母细胞瘤对作为放射增敏剂的组蛋白去乙酰化酶抑制剂（HDACi）表现出抗性。我们在源自患者的胶质母细胞瘤干细胞样细胞（GSC）培养物中，使用Bcl-2抑制剂Obatoclax操纵Bcl-2家族蛋白时，研究了SAHA/放疗（RTx）和LBH589/RTx的疗效。一般来说，GSC培养物中磷酸酶和张力蛋白同源物（PTEN）存在缺失。协同作用通过Chou Talalay方法确定。通过测量半胱天冬酶-3/7、Bcl-XL、Mcl-1和LC3BI/II蛋白来研究对细胞凋亡和自噬的影响。研究了治疗反应与肿瘤的O6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）启动子甲基化状态、复发及基因表达水平之间的关系。Obatoclax与SAHA和LBH589协同作用，使细胞对HDACi/RTx敏感。超过50%的GSC培养物对单独使用任一种药物的Obatoclax有反应。与HDACi/RTx联合治疗时，Obatoclax比其他治疗更有效地增加了半胱天冬酶-3/7并抑制了Bcl-2家族蛋白Bcl-XL和Mcl-1。确定了预测治疗反应的基因，包括含F-box/ WD重复蛋白-7，其先前与Bcl-2抑制和HDACi敏感性有关。我们强调了Bcl-2蛋白与HDACi放射增敏之间的功能关系，并通过使用Bcl-2抑制剂Obatoclax为提高胶质母细胞瘤的反应性提供了一个靶点。
