Chekkat Neila, Lombardo Caterina M, Seguin Cendrine, Lechner Marie-Charlotte, Dufour Florent, Nominé Yves, De Giorgi Marcella, Frisch Benoit, Micheau Olivier, Guichard Gilles, Altschuh Danièle, Fournel Sylvie
Laboratoire de Conception et Application de Molécules Bioactives, UMR 7199 CNRS, Université de Strasbourg, 67401 Illkirch, France.
Université de Bordeaux, CBMN, UMR 5248, Institut Européen de Chimie et Biologie, 33607 Pessac, France.
Oncotarget. 2018 Feb 17;9(21):15566-15578. doi: 10.18632/oncotarget.24526. eCollection 2018 Mar 20.
Tumor Necrosis Factor Receptor Apoptosis Inducing Ligand (TRAIL) appears as an interesting candidate for targeted cancer therapy as it induces apoptosis in cancer cells without toxicity to normal cells. TRAIL elicits apoptosis through agonist death receptor TRAIL-R1 and TRAIL-R2 engagement. Nevertheless, recombinant soluble TRAIL and monoclonal antibodies against these receptors demonstrated insufficient efficacy in clinical trials. This may be explained by the cell-type dependency of the apoptotic response, itself influenced by the effect on ligand binding mode of factors such as the level of receptor oligomerization or glycosylation. To investigate the relation between binding mode and signaling, we used previously described synthetic divalent and monovalent peptides specific for TRAIL-R2. We measured their pro-apoptotic activity on three cancer cell lines sensitive to rhTRAIL induced-apoptosis and monitored their cell-surface binding kinetics. The two divalent peptides bound with strong affinity to TRAIL-R2 expressed on B lymphoma BJAB cells and induced a high degree of apoptosis. By contrast, the same peptides bound weakly to TRAIL-R2 expressed at the surface of the human colon cancer HCT116 or T lymphoma Jurkat cell lines and did not induce their apoptosis. Cross-linking experiments suggest that these differences could be afforded by variations in the TRAIL-R2 oligomerization state at cell surface before ligand addition. Moreover divalent peptides showed a different efficiency in BJAB apoptosis induction, and kinetic distribution analysis of the BJAB binding curves suggested subtle differences in binding mechanisms. Thus our data support a relation between the cell-surface binding mode of the peptides and their pro-apoptotic activity. In this case the precise characterization of ligand binding to the surface of living cells would be predictive of the therapeutic potential of TRAIL-R2 synthetic ligands prior to clinical trials.
肿瘤坏死因子受体凋亡诱导配体（TRAIL）似乎是靶向癌症治疗的一个有吸引力的候选物，因为它能诱导癌细胞凋亡而对正常细胞无毒。TRAIL通过激动剂死亡受体TRAIL-R1和TRAIL-R2的结合引发凋亡。然而，重组可溶性TRAIL和针对这些受体的单克隆抗体在临床试验中显示出疗效不足。这可能是由于凋亡反应的细胞类型依赖性，其本身受诸如受体寡聚化水平或糖基化等因素对配体结合模式的影响。为了研究结合模式与信号传导之间的关系，我们使用了先前描述的对TRAIL-R2特异的合成二价和单价肽。我们测量了它们对三种对rhTRAIL诱导凋亡敏感的癌细胞系的促凋亡活性，并监测了它们的细胞表面结合动力学。这两种二价肽与B淋巴瘤BJAB细胞上表达的TRAIL-R2具有强亲和力结合，并诱导高度凋亡。相比之下，相同的肽与人类结肠癌细胞HCT116或T淋巴瘤Jurkat细胞系表面表达的TRAIL-R2结合较弱，并且不诱导它们的凋亡。交联实验表明，这些差异可能是由配体添加前细胞表面TRAIL-R2寡聚化状态的变化所致。此外，二价肽在BJAB凋亡诱导中表现出不同的效率，并且BJAB结合曲线的动力学分布分析表明结合机制存在细微差异。因此，我们的数据支持肽的细胞表面结合模式与其促凋亡活性之间的关系。在这种情况下，在临床试验之前，对配体与活细胞表面结合的精确表征将预测TRAIL-R2合成配体的治疗潜力。
