Creative Research Initiative Center for concurrent control of emphysema and lung cancer, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea.
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea.
Theranostics. 2021 Jan 1;11(6):2932-2952. doi: 10.7150/thno.49876. eCollection 2021.
Cancer stem cells (CSCs) are known to cause tumor recurrence and drug resistance. The heat shock protein (HSP) system plays a major role in preserving expression and function of numerous oncoproteins, including those involved in the CSC activities. We explored novel anticancer drugs, especially those targeting HSP components required for the functional role of CSCs. Investigation of the role of the HSP system in CSCs and screening of a natural product chemical library were performed by utilizing cancer cell lines, primary cultures of patient-derived xenografts (PDXs), and their putative CSC subpopulations (i.e., those grown under sphere-forming conditions, stably transfected with reporter vectors carrying or promoters, or carrying high ALDH activity) in vitro and PDX and -driven tumor models in vivo. Regulation of the HSP system was investigated by immunoprecipitation, drug affinity responsive target stability assay, binding experiments using ATP-agarose beads and biotinylated drug, and docking analysis. The HSP system was activated in CSCs via transcriptional upregulation of the HSP system components, especially HSP70. Evodiamine (Evo) was identified to induce apoptosis in both CSC and bulk non-CSC populations in human lung, colon, and breast cancer cells and their sublines with chemoresistance. Evo administration decreased the multiplicity, volume, and load of lung tumors in transgenic mice and the growth of cancer cell line- and PDX-derived tumors without detectable toxicity. Mechanistically, Evo disrupted the HSP system by binding the N-terminal ATP-binding pocket of HSP70 and causing its ubiquitin-mediated degradation. Our findings illustrate HSP70 as a potential target for eliminating CSCs and Evo as an effective HSP70-targeting anticancer drug eradicating both CSCs and non-CSCs with a minimal toxicity.
肿瘤干细胞（CSCs）被认为会导致肿瘤复发和耐药。热休克蛋白（HSP）系统在维持许多癌蛋白的表达和功能方面发挥着重要作用，包括那些与 CSC 活性相关的蛋白。我们探索了新型抗癌药物，特别是那些针对 HSP 成分的药物，这些成分对于 CSCs 的功能至关重要。通过利用癌细胞系、患者来源的异种移植（PDX）的原代培养物及其假定的 CSC 亚群（即在球体形成条件下生长的、稳定转染携带 或 启动子的报告载体的、或携带高 ALDH 活性的），以及在体内 PDX 和 驱动的肿瘤模型，我们研究了 HSP 系统在 CSCs 中的作用，并对天然产物化学文库进行了筛选。通过免疫沉淀、药物亲和反应靶标稳定性测定、使用 ATP-琼脂糖珠和生物素化药物的结合实验以及对接分析，研究了 HSP 系统的调节。HSP 系统通过 HSP 系统成分（特别是 HSP70）的转录上调在 CSCs 中被激活。鉴定出吴茱萸碱（Evo）可诱导人肺、结肠和乳腺癌细胞及其具有化学抗性的亚系中的 CSC 和大量非 CSC 群体凋亡。Evo 的给药降低了 转基因小鼠肺部肿瘤的多发性、体积和负荷，以及癌症细胞系和 PDX 衍生肿瘤的生长，且没有可检测到的毒性。从机制上讲，Evo 通过结合 HSP70 的 N 端 ATP 结合口袋并导致其泛素介导的降解来破坏 HSP 系统。我们的研究结果表明 HSP70 是消除 CSCs 的潜在靶标，而 Evo 是一种有效的 HSP70 靶向抗癌药物，可在最小毒性的情况下根除 CSCs 和非 CSCs。
