National Center for Liver Cancer, Naval Medical University, 366 Qianju Road, Shanghai, 201805, China; Key Laboratory of Signaling Regulation and Targeting Therapy of Liver Cancer (SMMU), Ministry of Education. 225 Changhai Road, Shanghai 200438, China.
Department of Pathology, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine (TCM), 358 Datong Road, Shanghai, 200137, China.
Phytomedicine. 2024 Aug;131:155790. doi: 10.1016/j.phymed.2024.155790. Epub 2024 May 29.
A balanced protein homeostasis network helps cholangiocarcinoma (CCA) maintain their oncogenic growth, and disrupting proteostasis therapeutically will induce proteotoxic stress. Phosphatase and tensin homolog (PTEN) have been reported to be involved in proteostasis, and PTEN-associated pathways are commonly altered in CCA. Celastrol, a triterpene from plants, exhibits cytotoxic effects in various types of cancer. However, the underlying mechanisms remain unclear.
We investigated the therapeutic effect of celastrol in CCA and identified the molecular characteristics of tumors that were sensitive to celastrol. The target of celastrol was explored. We then evaluated the candidate combination therapeutic strategy to increase the effectiveness of celastrol in celastrol-insensitive CCA tumors.
Various CCA cells were categorized as either celastrol-sensitive or celastrol-insensitive based on their response to celastrol. The molecular characteristics of cells from different groups were determined by RNA-seq. PTEN status and its role in proteasome activity in CCA cells were investigated. The CMAP analysis, molecular docking, and functional assay were performed to explore the effect of celastrol on proteasome activities. The correlation between PTEN status and clinical outcomes, as well as proteasomal activity, were measured in CCA patients. The synergistic therapeutic effect of autophagy inhibitors on celastrol-insensitive CCA cells were measured.
Diverse responses to celastrol were observed in CCA cells. PTEN expression varied among different CCA cells, and its status could impact cell sensitivity to celastrol: PTEN tumor cells were resistant to celastrol, while PTEN cells were more sensitive. Celastrol induced proteasomal dysregulation in CCA cells by directly targeting PSMB5. Cells with low PTEN status transcriptionally promoted proteasome subunit expression in an AKT-dependent manner, making these cells more reliant on proteasomal activities to maintain proteostasis. This caused the PTEN CCA cells sensitive to celastrol. A negative correlation was found between PTEN levels and the proteasome signature in CCA patients. Moreover, celastrol treatment could induce autophagy in PTEN CCA cells. Disrupting the autophagic pathway in PTEN CCA cells enhanced the cytotoxic effect of celastrol.
PTEN status in CCA cells determines their sensitivity to celastrol, and autophagy inhibitors could enhance the anti-tumor effect in PTEN CCA.
平衡的蛋白质稳态网络有助于胆管癌（CCA）维持其致癌生长，而通过治疗性破坏蛋白质稳态会诱导蛋白质毒性应激。磷酸酶和张力蛋白同源物（PTEN）已被报道参与蛋白质稳态，并且 CCA 中常见的 PTEN 相关途径发生改变。从植物中提取的三萜 celastrol 对各种类型的癌症具有细胞毒性作用。然而，其潜在机制尚不清楚。
我们研究了 celastrol 在 CCA 中的治疗效果，并确定了对 celastrol 敏感的肿瘤的分子特征。探讨了 celastrol 的靶标。然后，我们评估了候选联合治疗策略，以增加 celastrol 在 celastrol 不敏感的 CCA 肿瘤中的有效性。
根据对 celastrol 的反应，将各种 CCA 细胞分为 celastrol 敏感或 celastrol 不敏感细胞。通过 RNA-seq 确定不同组细胞的分子特征。研究了 CCA 细胞中 PTEN 状态及其在蛋白酶体活性中的作用。进行了 CMAP 分析、分子对接和功能测定，以探讨 celastrol 对蛋白酶体活性的影响。测量了 CCA 患者中 PTEN 状态与临床结局以及蛋白酶体活性之间的相关性。测量了自噬抑制剂对 celastrol 不敏感的 CCA 细胞的协同治疗效果。
CCA 细胞对 celastrol 的反应不同。不同的 CCA 细胞中存在不同的 PTEN 表达，其状态可能影响细胞对 celastrol 的敏感性：PTEN 肿瘤细胞对 celastrol 有抗性，而 PTEN 细胞则对 celastrol 更敏感。Celastrol 通过直接靶向 PSMB5 诱导 CCA 细胞中蛋白酶体失调。转录水平上低 PTEN 状态的细胞以 AKT 依赖性方式促进蛋白酶体亚基表达，使这些细胞更依赖蛋白酶体活性来维持蛋白质稳态。这导致 PTEN CCA 细胞对 celastrol 敏感。CCA 患者中发现 PTEN 水平与蛋白酶体特征之间存在负相关。此外，celastrol 处理可在 PTEN CCA 细胞中诱导自噬。在 PTEN CCA 细胞中破坏自噬途径可增强 celastrol 的细胞毒性作用。
CCA 细胞中的 PTEN 状态决定了其对 celastrol 的敏感性，自噬抑制剂可增强 PTEN CCA 的抗肿瘤作用。
