Department of Clinical Pharmaceutics, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji, Japan.
Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Hyogo Medical University, Kobe, Japan.
Anticancer Res. 2023 Oct;43(10):4349-4357. doi: 10.21873/anticanres.16630.
BACKGROUND/AIM: Mammalian target of rapamycin (mTOR) inhibitors represent the standard of care for metastatic renal cell carcinoma (RCC). However, treatment outcomes are relatively poor, suggesting a potential problem with tolerating mTOR inhibitors. The aim of this study was to establish everolimus-resistant sublines and to compare their molecular characteristics with those of their counterparts.
Human-derived RCC, Caki-2, and 786-O cells were continuously exposed to everolimus at 1 μM, and the established resistant sublines were designated as Caki/EV and 786/EV, respectively. Cellular characteristics were compared between both cells.
Caki/EV and 786/EV cells showed a decrease in sensitivity to everolimus as well as other mTOR inhibitors. Expression of mTOR and its effectors exhibited no alteration in resistant sublines and their counterparts. However, phosphorylation of S6K, an index of mTOR activity, decreased in resistant sublines. PCR array analysis of mTOR signaling pathway-related factors indicated that the expression of INSR, TP53, and IGFBP3 increased in Caki/EV cells, whereas that of TELO2, HRAS, and SGK1 was up-regulated in 786/EV cells. The levels of DDIT4, DEPTOR, HIF1A, and PLD1 mRNAs decreased in both cell lines.
The novel everolimus-resistant Caki/EV and 786/EV cells exhibited cross-resistance to other mTOR inhibitors and decreased mTOR activity. Furthermore, down-regulation of DDIT4, DEPTOR, HIF1A, and PLD1 may contribute to everolimus resistance.
背景/目的：哺乳动物雷帕霉素靶蛋白（mTOR）抑制剂是转移性肾细胞癌（RCC）的标准治疗方法。然而，治疗效果相对较差，表明对 mTOR 抑制剂的耐受性可能存在问题。本研究旨在建立依维莫司耐药亚系，并比较其与相应细胞系的分子特征。
将人源肾癌细胞系 Caki-2 和 786-O 细胞持续暴露于依维莫司 1 μM 中，建立的耐药亚系分别命名为 Caki/EV 和 786/EV。比较两种细胞之间的细胞特征。
Caki/EV 和 786/EV 细胞对依维莫司和其他 mTOR 抑制剂的敏感性降低。耐药亚系及其对应细胞中 mTOR 及其效应物的表达没有改变。然而，mTOR 活性的指标 S6K 的磷酸化在耐药亚系中降低。mTOR 信号通路相关因子的 PCR 阵列分析表明，Caki/EV 细胞中 INSR、TP53 和 IGFBP3 的表达增加，而 786/EV 细胞中 TELO2、HRAS 和 SGK1 的表达上调。两种细胞系中 DDIT4、DEPTOR、HIF1A 和 PLD1 的 mRNA 水平降低。
新型依维莫司耐药 Caki/EV 和 786/EV 细胞对其他 mTOR 抑制剂表现出交叉耐药性，并降低了 mTOR 活性。此外，DDIT4、DEPTOR、HIF1A 和 PLD1 的下调可能有助于依维莫司耐药。
