Department of General Surgery, First Affiliated Hospital of Soochow University, No.899 Pinghai Road, Suzhou City, 215000, Jiangsu Province, China.
Departments of General Surgery, Yancheng City No.1 People's Hospital, Yancheng City, Jiangsu Province, China.
Biochem Genet. 2022 Apr;60(2):558-575. doi: 10.1007/s10528-021-10110-6. Epub 2021 Jul 27.
Resistance to cisplatin (CDDP) remains a major challenge for the treatment of gastric cancer (GC). Circular RNAs (circRNAs) have been implicated in the development of CDDP resistance of GC. However, the precise actions of circ_0001017 in CDDP resistance of GC remain to be elucidated. The levels of circ_0001017, microRNA (miR)-543 and PH-domain and leucine-rich repeat protein phosphatase 2 (PHLPP2) mRNA were gauged by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was used to analyze the protein levels of Vimentin, N-cadherin, E-cadherin, and PHLPP2. Ribonuclease R (RNase R) assay was applied to evaluate the stability of circ_0001017. Cell viability and proliferation, colony formation ability, cell cycle distribution and apoptosis, and migration and invasion were detected by the Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, and transwell assays, respectively. Direct relationship between miR-543 and circ_0001017 or PHLPP2 was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Xenograft model assay was used to assess the function of circ_0001017 in vivo. Low expression of circ_0001017 was associated with CDDP resistance of GC. Enforced expression of circ_0001017 impeded growth, metastasis, and enhanced apoptosis of HGC-27/R and AGS/R cells and sensitized them to CDDP in vitro. Circ_0001017 targeted miR-543, and circ_0001017 regulated CDDP-resistant cell behaviors and CDDP sensitivity by suppressing miR-543. PHLPP2 was a direct target of miR-543, and circ_0001017 controlled PHLPP2 expression through miR-543. Moreover, miR-543 knockdown-mediated promotion of PHLPP2 impacted CDDP-resistant cell behaviors and CDDP sensitivity in vitro. Additionally, elevated expression of circ_0001017 hindered growth of HGC-27/R cells and sensitized them to CDDP in vivo. Our findings demonstrated that enforced expression of circ_0001017 suppressed malignant behaviors and enhanced CDDP sensitivity of CDDP-resistant GC cells at least partially by the miR-543/PHLPP2 axis.
顺铂（CDDP）耐药仍然是胃癌（GC）治疗的主要挑战。环状 RNA（circRNA）已被牵涉到 GC 中 CDDP 耐药的发展中。然而，circ_0001017 在 GC 中 CDDP 耐药中的确切作用仍有待阐明。通过实时定量聚合酶链反应（qRT-PCR）测定 circ_0001017、微小 RNA（miR）-543 和 PH 结构域和富含亮氨酸重复蛋白磷酸酶 2（PHLPP2）mRNA 的水平。通过蛋白质印迹法分析波形蛋白、N-钙粘蛋白、E-钙粘蛋白和 PHLPP2 的蛋白水平。应用核糖核酸酶 R（RNase R）测定评估 circ_0001017 的稳定性。通过细胞计数试剂盒-8（CCK-8）、集落形成、流式细胞术和 Transwell 测定分别检测细胞活力和增殖、集落形成能力、细胞周期分布和凋亡以及迁移和侵袭。通过双荧光素酶报告和 RNA 免疫沉淀（RIP）测定验证 miR-543 与 circ_0001017 或 PHLPP2 之间的直接关系。利用异种移植模型测定评估 circ_0001017 在体内的功能。circ_0001017 的低表达与 GC 的 CDDP 耐药有关。circ_0001017 的过表达抑制 HGC-27/R 和 AGS/R 细胞的生长、转移和增强凋亡，并在体外使它们对 CDDP 敏感。circ_0001017 靶向 miR-543，circ_0001017 通过抑制 miR-543 调节 CDDP 耐药细胞行为和 CDDP 敏感性。PHLPP2 是 miR-543 的直接靶标，circ_0001017 通过 miR-543 控制 PHLPP2 的表达。此外，miR-543 敲低介导的 PHLPP2 促进体外 CDDP 耐药细胞行为和 CDDP 敏感性。此外，circ_0001017 的高表达抑制 HGC-27/R 细胞的生长并在体内使其对 CDDP 敏感。我们的研究结果表明，circ_0001017 的过表达至少部分通过 miR-543/PHLPP2 轴抑制 CDDP 耐药 GC 细胞的恶性行为并增强 CDDP 敏感性。
