Krossa Sebastian, Schmitt Anne Dorothée, Hattermann Kirsten, Fritsch Jürgen, Scheidig Axel J, Mehdorn Hubertus Maximilian, Held-Feindt Janka
Institute of Zoology, Department of Structural Biology, 24118 Kiel, Germany.
Department of Neurosurgery, University of Schleswig-Holstein Medical Center, 24105 Kiel, Germany.
Oncotarget. 2015 Aug 28;6(25):21029-45. doi: 10.18632/oncotarget.3763.
The Twist-1 transcription factor and its interacting protein Akirin-2 regulate apoptosis. We found that in glioblastomas, highly malignant brain tumors, Akirin-2 and Twist-1 were expressed in glial fibrillary acidic protein positive tumor regions as well as in tumor endothelial cells and infiltrating macrophages / microglia. Temozolomide (TMZ) induced the expression of both molecules, partly shifting their nuclear to cytosolic localization. The knock-down (kd) of Akirin-2 increased the activity of cleaved (c)Caspase-3/-7, the amounts of cCaspases-3, -7 and cPARP-1 and resulted in an increased number of apoptotic cells after TMZ exposure. Glioblastoma cells containing decreased amounts of Akirin-2 after kd contained increased amounts of cCaspase-3 as determined by the ImageStreamx Mark II technology. For Twist-1, similar results were obtained with the exception that the combination of TMZ treatment and Twist-1 kd failed to significantly reduce chemoresistance compared with controls. This could be attributed to a cell population containing only slightly increased cCaspase-3 together with decreased Twist-1 levels, which was clearly larger than the respective population observed under Akirin-2 kd. Our results showed that, compared with Twist-1, Akirin-2 is the more promising target for RNAi strategies antagonizing Twist-1/Akirin-2 facilitated glioblastoma cell survival.
Twist-1转录因子及其相互作用蛋白Akirin-2调节细胞凋亡。我们发现，在胶质母细胞瘤（一种高度恶性的脑肿瘤）中，Akirin-2和Twist-1在胶质纤维酸性蛋白阳性的肿瘤区域以及肿瘤内皮细胞和浸润的巨噬细胞/小胶质细胞中均有表达。替莫唑胺（TMZ）可诱导这两种分子的表达，部分改变它们从细胞核到细胞质的定位。敲低（kd）Akirin-2可增加裂解型（c）Caspase-3/-7的活性、cCaspases-3、-7和cPARP-1的量，并导致TMZ处理后凋亡细胞数量增加。通过ImageStreamx Mark II技术测定，kd后Akirin-2含量降低的胶质母细胞瘤细胞中cCaspase-3含量增加。对于Twist-1，也获得了类似的结果，但与对照组相比，TMZ处理和Twist-1 kd的联合使用未能显著降低化疗耐药性。这可能归因于一个细胞群体，其cCaspase-3仅略有增加，同时Twist-1水平降低，且该群体明显大于在Akirin-2 kd下观察到的相应群体。我们的结果表明，与Twist-1相比，Akirin-2是RNAi策略中更有前景的靶点，可对抗Twist-1/Akirin-2促进的胶质母细胞瘤细胞存活。
