Hinz S, Trauzold A, Boenicke L, Sandberg C, Beckmann S, Bayer E, Walczak H, Kalthoff H, Ungefroren H
Research Unit Molecular Oncology, Clinic for General Surgery and Thoracic Surgery, Christian-Albrechts-University, Kiel, Germany.
Oncogene. 2000 Nov 16;19(48):5477-86. doi: 10.1038/sj.onc.1203936.
In this study we sought to clarify the role of the proapoptotic potential of mitochondria in the death pathway emanating from the TRAIL (APO-2L) and CD95 receptors in pancreatic carcinoma cells. We focused on the role of the Bcl-2 family member Bcl-XL, using three pancreatic carcinoma cell lines as a model system, two of which have high (Panc-1, PancTuI) and one has low (Colo357) Bcl-XL expression. In these cell lines, the expression of Bcl-XL correlated with sensitivity to apoptosis induced by TRAIL or anti-CD95. Flow cytometric analysis revealed cell surface expression of TRAIL-R1 and TRAIL-R2 on PancTuI and Colo357, and TRAIL-R2 on Panc-1 cells. In Colo357 cells retrovirally transduced with Bcl-XL, caspase-8 activation in response to treatment with TRAIL or anti-CD95 antibody was not different from parental cells and EGFP-transfected controls, however, apoptosis was completely suppressed as measured by the mitochondrial transmembrane potential deltapsim, caspase-3 activity (PARP cleavage) and DNA-fragmentation. Inhibition of Bcl-XL function by overexpression of Bax or administration of antisense oligonucleotides against Bcl-XL mRNA resulted in sensitization of Panc-1 cells to TRAIL and PancTuI cells to anti-CD95 antibody-induced cell death. The results show that Bcl-XL can protect pancreatic cancer cells from CD95- and TRAIL-mediated apoptosis. Thus, in these epithelial tumour cells the mitochondrially mediated 'type II' pathway of apoptosis induction is not only operative regarding the CD95 system but also regarding the TRAIL system.
在本研究中，我们试图阐明线粒体促凋亡潜能在源自TRAIL（APO-2L）和CD95受体的胰腺癌细胞死亡途径中的作用。我们以三种胰腺癌细胞系作为模型系统，聚焦于Bcl-2家族成员Bcl-XL的作用，其中两种细胞系Bcl-XL表达水平高（Panc-1、PancTuI），一种表达水平低（Colo357）。在这些细胞系中，Bcl-XL的表达与对TRAIL或抗CD95诱导的凋亡的敏感性相关。流式细胞术分析显示，PancTuI和Colo357细胞表面表达TRAIL-R1和TRAIL-R2，Panc-1细胞表面表达TRAIL-R2。在用Bcl-XL进行逆转录病毒转导的Colo357细胞中，对TRAIL或抗CD95抗体处理的反应中，caspase-8激活与亲代细胞和EGFP转染对照无差异，然而，通过线粒体跨膜电位Δψｍ、caspase-3活性（PARP裂解）和DNA片段化检测，凋亡被完全抑制。通过过表达Bax或给予针对Bcl-XL mRNA的反义寡核苷酸抑制Bcl-XL功能，导致Panc-1细胞对TRAIL敏感，PancTuI细胞对抗CD95抗体诱导的细胞死亡敏感。结果表明，Bcl-XL可保护胰腺癌细胞免受CD95和TRAIL介导的凋亡。因此，在这些上皮肿瘤细胞中，线粒体介导的“II型”凋亡诱导途径不仅在CD95系统中起作用，在TRAIL系统中也起作用。
