背景:平衡的蛋白质稳态网络有助于胆管癌(CCA)维持其致癌生长,并且在治疗上破坏蛋白稳定将诱导蛋白毒性应激。磷酸酶和张力蛋白同源物(PTEN)已被报道参与蛋白质抑制,和PTEN相关通路在CCA中通常发生改变。雷公藤多,来自植物的三萜,在各种类型的癌症中表现出细胞毒性作用。然而,潜在机制尚不清楚.
目的:我们研究了雷公藤红素在CCA中的治疗作用,并确定了对雷公藤红素敏感的肿瘤的分子特征。探索了雷公藤红素的靶标。然后,我们评估了候选组合治疗策略,以增加雷公藤红素对雷公藤红素不敏感的CCA肿瘤的有效性。
方法:根据对雷公藤红素的反应,将各种CCA细胞分为雷公藤红素敏感或雷公藤红素不敏感。通过RNA-seq确定来自不同组的细胞的分子特征。研究了CCA细胞中PTEN状态及其在蛋白酶体活性中的作用。CMAP分析,分子对接,并进行功能测定以探讨雷公藤红素对蛋白酶体活性的影响。PTEN状态与临床结果之间的相关性,以及蛋白酶体活动,在CCA患者中进行了测量。测量自噬抑制剂对雷公藤红素不敏感的CCA细胞的协同治疗作用。
结果:在CCA细胞中观察到对雷公藤红素的不同反应。PTEN表达在不同的CCA细胞中不同,其状态可能影响细胞对雷公藤红素的敏感性:PTENhigh肿瘤细胞对雷公藤红素具有抗性,而PTENlow细胞更敏感。雷公藤红素通过直接靶向PSMB5诱导CCA细胞中的蛋白酶体失调。具有低PTEN状态的细胞转录以AKT依赖性方式促进蛋白酶体亚基表达,使这些细胞更依赖于蛋白酶体活动来维持蛋白质的稳定。这导致PTENlowCCA细胞对雷公藤红素敏感。在CCA患者中,PTEN水平与蛋白酶体特征之间存在负相关。此外,雷公藤红素处理可诱导PTENhighCCA细胞自噬。破坏PTENhighCCA细胞中的自噬途径可增强雷公藤红素的细胞毒性作用。
结论:CCA细胞中的PTEN状态决定了它们对雷公藤红素的敏感性,自噬抑制剂可增强PTENhighCCA的抗肿瘤作用。
BACKGROUND: 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.
OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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: PTENhigh tumor cells were resistant to celastrol, while PTENlow 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 PTENlow 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 PTENhigh CCA cells. Disrupting the autophagic pathway in PTENhigh CCA cells enhanced the cytotoxic effect of celastrol.
CONCLUSIONS: PTEN status in CCA cells determines their sensitivity to celastrol, and autophagy inhibitors could enhance the anti-tumor effect in PTENhigh CCA.