XIAP在TRAIL抗性细胞HCT116 bax-/-中的作用机制研究

The Machnism of XIAP and TRAIL Resistance in HCT116 bax-/-

摘要:

肿瘤坏死因子相关凋亡诱导配体（Tumor necrosis factor related apoptosis inducing ligand, TRAIL) 是肿瘤坏死因子（TNF）超家族中的一员，其通过与癌细胞表面特异性受体DR4（Death Receptor 4）或DR5（Death Receptor 5）结合，激活细胞凋亡信号通路，诱导肿瘤细胞凋亡，对正常细胞却没有毒害作用。因此TRAIL是一种很有潜力的治疗癌症的药物。但是往往有少数肿瘤细胞能够逃脱TRAIL诱导凋亡，对TRAIL产生抗药性。抗性机制与很多基因有关，例如人直肠癌细胞HCT116，当靶向敲除两个bax等位基因时，能使细胞抗TRAIL诱导凋亡。即HCT116 bax-/-是抗TRAIL的。为了探究其分子机制，本课题利用目前最热的基因定点编辑技术Clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated(Cas)9系统将HCT116 bax-/- 的XIAP(X-linked inhibitor of apoptosis protein) 敲除后，恢复了其对TRAIL的敏感，由此证明敲除XIAP能克服HCT116 bax-/-对TRAIL的抗性。这些发现对肿瘤细胞抗TRAIL的分子机理研究以及肿瘤的个性化治疗有非常重要的意义。

Abstract:

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is one of the members of the tumor necrosis factor (TNF) superfamily. It can activate the apoptosis signaling pathways through engagement of the specific death receptors (DR4) or (DR5) in a broad range of cancer cell lines but not in normal cells. Thus, TRAIL is a potential anti-cancer agent. However, a small number of cancer cells may escape TRAIL induced cell death, and become resistant to it. For instance, targeted deletion of bax gene in human colorectal cancer cell line HCT116 (HCT116 bax-/-) renders the cells resistant to TRIAL induced apoptosis. In this project, we used gene-targeting technology CRISPR/Cas9 system to knock out the XIAP gene in HCT116 bax-/- cells. We showed that, as predicted, the loss of XIAP led to HCT116 bax-/- cells to overcome TRAIL resistance caused by bax deletion. This finding is significant for future study of the molecular mechanism behind cancer cell resistance to TRAIL and may help future personalized anti-cancer treatment.