Brain Cancer Research and Therapy Laboratory, Koç University Research Center for Translational Medicine, Istanbul, 34450, Turkey.
Koç University School of Medicine, Istanbul, 34450, Turkey.
Oncogene. 2021 May;40(18):3201-3216. doi: 10.1038/s41388-021-01697-6. Epub 2021 Mar 25.
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces tumor cell-specific apoptosis, making it a prime therapeutic candidate. However, many tumor cells are either innately TRAIL-resistant, or they acquire resistance with adaptive mechanisms that remain poorly understood. In this study, we generated acquired TRAIL resistance models using multiple glioblastoma (GBM) cell lines to assess the molecular alterations in the TRAIL-resistant state. We selected TRAIL-resistant cells through chronic and long-term TRAIL exposure and noted that they showed persistent resistance both in vitro and in vivo. Among known TRAIL-sensitizers, proteosome inhibitor Bortezomib, but not HDAC inhibitor MS-275, was effective in overcoming resistance in all cell models. This was partly achieved through upregulating death receptors and pro-apoptotic proteins, and downregulating major anti-apoptotic members, Bcl-2 and Bcl-xL. We showed that CRISPR/Cas9 mediated silencing of DR5 could block Bortezomib-mediated re-sensitization, demonstrating its critical role. While overexpression of Bcl-2 or Bcl-xL was sufficient to confer resistance to TRAIL-sensitive cells, it failed to override Bortezomib-mediated re-sensitization. With RNA sequencing in multiple paired TRAIL-sensitive and TRAIL-resistant cells, we identified major alterations in inflammatory signaling, particularly in the NF-κB pathway. Inhibiting NF-κB substantially sensitized the most resistant cells to TRAIL, however, the sensitization effect was not as great as what was observed with Bortezomib. Together, our findings provide new models of acquired TRAIL resistance, which will provide essential tools to gain further insight into the heterogeneous therapy responses within GBM tumors. Additionally, these findings emphasize the critical importance of combining proteasome inhibitors and pro-apoptotic ligands to overcome acquired resistance.
肿瘤坏死因子相关凋亡诱导配体（TRAIL）诱导肿瘤细胞特异性凋亡，使其成为主要的治疗候选药物。然而，许多肿瘤细胞要么天生对 TRAIL 具有抗性，要么通过适应性机制获得抗性，而这些机制仍知之甚少。在这项研究中，我们使用多种脑胶质瘤（GBM）细胞系生成获得性 TRAIL 耐药模型，以评估 TRAIL 耐药状态下的分子变化。我们通过慢性和长期 TRAIL 暴露选择 TRAIL 耐药细胞，并注意到它们在体外和体内均表现出持续的耐药性。在已知的 TRAIL 敏化剂中，蛋白酶体抑制剂硼替佐米而非组蛋白去乙酰化酶抑制剂 MS-275 可有效克服所有细胞模型中的耐药性。这部分是通过上调死亡受体和促凋亡蛋白，下调主要抗凋亡成员 Bcl-2 和 Bcl-xL 来实现的。我们表明，CRISPR/Cas9 介导的 DR5 沉默可以阻断硼替佐米介导的再敏化，证明了其关键作用。虽然 Bcl-2 或 Bcl-xL 的过表达足以赋予 TRAIL 敏感细胞抗性，但它无法克服硼替佐米介导的再敏化。通过对多个配对的 TRAIL 敏感和 TRAIL 耐药细胞进行 RNA 测序，我们确定了炎症信号的主要改变，特别是在 NF-κB 通路中。抑制 NF-κB 可显著增加最耐药细胞对 TRAIL 的敏感性，但敏感性增强效果不如硼替佐米明显。总之，我们的研究结果提供了获得性 TRAIL 耐药的新模型，这将为深入了解 GBM 肿瘤内异质性治疗反应提供必要的工具。此外，这些发现强调了联合蛋白酶体抑制剂和促凋亡配体克服获得性耐药的重要性。
