Hao C, Beguinot F, Condorelli G, Trencia A, Van Meir E G, Yong V W, Parney I F, Roa W H, Petruk K C
Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada.
Cancer Res. 2001 Feb 1;61(3):1162-70.
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) preferentially triggers apoptosis in tumor cells versus normal cells, thus providing a therapeutic potential. In this study, we examined a large panel of human malignant glioma cell lines and primary cultures of normal human astrocytes for their sensitivity to TRAIL. Of 13 glioma cell lines, 3 were sensitive (80-100% death), 4 were partially resistant (30-79% death), and 6 were resistant (< 30% death). Normal astrocytes were also resistant. TRAIL-induced cell death was characterized by activation of caspase-8 and -3, poly(ADP-ribose) polymerase cleavage, and DNA fragmentation. Decoy receptor (DcR1 and DcR2) expression was limited in the glioma cell lines and did not correlate with TRAIL sensitivity. Both sensitive and resistant cell lines expressed TRAIL death receptor (DR5), adapter protein Fas-associated death domain (FADD), and caspase-8; but resistant cell lines expressed 2-fold higher levels of the apoptosis inhibitor phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes-15 kDa (PED/PEA-15). In contrast, cellular FADD-like IL-1beta-converting enzyme-like inhibitory protein (cFLIP) expression was similar in sensitive and resistant cells. Transfection of sense PED/PEA-15 cDNA in sensitive cells resulted in cell resistance, whereas transfection of antisense in resistant cells rendered them sensitive. Inhibition of protein kinase C (PKC) activity restored TRAIL sensitivity in resistant cells, suggesting that PED/ PEA-15 function might be dependent on PKC-mediated phosphorylation. In summary, TRAIL induces apoptosis in > 50% of glioma cell lines, and this killing occurs through activation of the DR pathway. This caspase-8-induced apoptotic cascade is regulated by intracellular PED/PEA-15, but not by cFLIP or decoy receptors. This pathway may be exploitable for glioma and possibly for other cancer therapies.
肿瘤坏死因子相关凋亡诱导配体（TRAIL）相较于正常细胞，更倾向于诱导肿瘤细胞凋亡，因此具有治疗潜力。在本研究中，我们检测了大量人类恶性胶质瘤细胞系以及正常人星形胶质细胞原代培养物对TRAIL的敏感性。在13种胶质瘤细胞系中，3种敏感（80 - 100%死亡），4种部分耐药（30 - 79%死亡），6种耐药（< 30%死亡）。正常星形胶质细胞也耐药。TRAIL诱导的细胞死亡表现为半胱天冬酶 - 8和 - 3的激活、聚（ADP - 核糖）聚合酶的裂解以及DNA片段化。诱骗受体（DcR1和DcR2）在胶质瘤细胞系中的表达有限，且与TRAIL敏感性无关。敏感和耐药细胞系均表达TRAIL死亡受体（DR5）、衔接蛋白Fas相关死亡结构域（FADD）和半胱天冬酶 - 8；但耐药细胞系中凋亡抑制蛋白富含糖尿病/富含星形胶质细胞的磷蛋白 - 15 kDa（PED/PEA - 15）的表达水平高出2倍。相反，细胞FADD样白细胞介素 - 1β转换酶样抑制蛋白（cFLIP）在敏感和耐药细胞中的表达相似。在敏感细胞中转染正义PED/PEA - 15 cDNA导致细胞耐药，而在耐药细胞中转染反义PED/PEA - 15 cDNA使其变得敏感。抑制蛋白激酶C（PKC）活性可恢复耐药细胞对TRAIL的敏感性，提示PED/PEA - 15的功能可能依赖于PKC介导的磷酸化。总之，TRAIL可诱导超过50%的胶质瘤细胞系凋亡，且这种杀伤是通过DR途径的激活发生的。这种由半胱天冬酶 - 8诱导的凋亡级联反应受细胞内PED/PEA - 15调控，但不受cFLIP或诱骗受体调控。该途径可能可用于胶质瘤以及其他癌症的治疗。
