Education Center of Green Pharmaceutical Sciences, Gifu Pharmaceutical University, Gifu, 502-8585, Japan.
Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu, 501-1196, Japan.
Chem Biol Interact. 2020 Dec 1;332:109295. doi: 10.1016/j.cbi.2020.109295. Epub 2020 Oct 20.
Irinotecan (CPT11) is widely prescribed for treatment of various intractable cancers such as advanced and metastatic colon cancer cells, but its continuous treatment promotes the resistance development. In this study, we established CPT11-resistant variants of three human colon cancer (DLD1, RKO and LoVo) cell lines, and found that gain of the resistance elicited an up-regulation of aldo-keto reductase (AKR) 1C3 in the cells. Additionally, the sensitivity to CPT11 toxicity was decreased and increased by overexpression and knockdown, respectively, of the enzyme. Moreover, the resistant cells suppressed formation of reactive 4-hydroxy-2-nonenal by CPT11 treatment, and the suppressive effect was almost completely abolished by addition of an AKR1C3 inhibitor. These results suggest that up-regulated AKR1C3 contributes to promotion of the chemoresistance by detoxifying the reactive aldehyde. Western blot and real-time polymerase-chain reaction analyses and ATP-binding cassette (ABC) B1-functional assay revealed that, among three ABC transporters, ABCB1 was the most highly up-regulated by development of the CPT11 resistance, inferring a significant contribution of pregnane-X receptor-dependent signaling to the ABCB1 up-regulation. The combined treatment with inhibitors of AKR1C3 and ABCB1 potently sensitized the resistant cells to CPT11 and its active metabolite SN38. Taken together, our results suggest that combination of AKR1C3 and ABCB1 inhibitors is effective as adjuvant therapy to enhance CPT11 sensitivity of intractable colon cancer cells.
伊立替康（CPT11）被广泛用于治疗各种难治性癌症，如晚期和转移性结肠癌细胞，但连续治疗会促进耐药性的发展。在这项研究中，我们建立了三种人结肠癌细胞（DLD1、RKO 和 LoVo）的 CPT11 耐药变体，发现耐药性的获得导致细胞中醛酮还原酶（AKR）1C3 的上调。此外，该酶的过表达和敲低分别降低和增加了对 CPT11 毒性的敏感性。此外，耐药细胞通过 CPT11 处理抑制了活性 4-羟基-2-壬烯醛的形成，而 AKR1C3 抑制剂的加入几乎完全消除了这种抑制作用。这些结果表明，上调的 AKR1C3 通过解毒反应性醛促进化学耐药性的发展。Western blot 和实时聚合酶链反应分析以及 ATP 结合盒（ABC）B1 功能测定显示，在三种 ABC 转运蛋白中，ABCB1 是通过 CPT11 耐药性发展而被上调最多的，这表明孕烷 X 受体依赖性信号对 ABCB1 上调有重要贡献。AKR1C3 和 ABCB1 抑制剂的联合治疗可有效增强耐药细胞对 CPT11 及其活性代谢物 SN38 的敏感性。总之，我们的研究结果表明，AKR1C3 和 ABCB1 抑制剂的联合治疗可作为辅助治疗增强难治性结肠癌细胞对 CPT11 的敏感性。
