Department of Oncology, Affiliated Hospital of Xiangnan University, Chenzhou, 423000, Hunan, China.
Department of Radiation Oncology, Affiliated Hospital of Xiangnan University, No.25 Renmin West Road, Beihu District, Chenzhou, 423000, Hunan, China.
J Mol Histol. 2024 Nov 29;56(1):9. doi: 10.1007/s10735-024-10287-1.
Cisplatin resistance is a clinical challenge limiting the treatment of nasopharyngeal carcinoma (NPC). CircRNAs have been evidenced as key molecules involved in tumor advancement and drug resistance. The present study aimed to elucidate the potential biological value of circKRT75 in NPC cisplatin resistance. CircKRT75 levels in NPC clinical samples and parental/resistant cell lines were analyzed based on qRT-PCR. CCK-8 and flow cytometry were adopted to assess the impacts of circKRT75 on the growth viability and apoptotic ability of NPC resistant cells. Meanwhile, western blot was performed to detect changes in the expression of apoptosis-related proteins. Bioinformatics analysis predicted miRNAs and mRNAs downstream of circKRT75, and the interaction between circKRT75 and downstream targets was validated by RNA pull-down, dual-luciferase reporter and rescue experiments. CircKRT75 was notably enhanced in NPC tissues and NPC cisplatin-resistant cells. Functional experiments disclosed that circKRT75 silencing repressed NPC-resistant cell growth and promoted apoptosis. Bioinformatics screening identified that circKRT75 performed as a molecular sponge for miR-659, and CCAR2 was a direct target of miR-659. Further rescue assays confirmed that miR-659 inhibitor restored the inhibitory effect of circKRT75 knockdown on the growth of drug-resistant cells, while CCAR2 silencing could reverse the promotion of NPC cisplatin resistance by circKRT75 upregulation. Additionally, animal experiments revealed that circKRT75 knockdown restrained NPC cisplatin resistance in vivo. CircKRT75 contributed to cisplatin resistance in NPC through miR-659/CCAR2 signaling, which provided a novel perspective and direction to solve the problem of chemoresistance in NPC.
顺铂耐药是限制鼻咽癌（NPC）治疗的临床挑战。CircRNAs 已被证明是参与肿瘤进展和耐药的关键分子。本研究旨在阐明 circKRT75 在 NPC 顺铂耐药中的潜在生物学价值。根据 qRT-PCR 分析 NPC 临床样本和亲本/耐药细胞系中的 circKRT75 水平。采用 CCK-8 和流式细胞术评估 circKRT75 对 NPC 耐药细胞生长活力和凋亡能力的影响。同时，进行 Western blot 检测凋亡相关蛋白表达的变化。生物信息学分析预测了 circKRT75 的下游 miRNA 和 mRNAs，通过 RNA 下拉、双荧光素酶报告基因和挽救实验验证了 circKRT75 与下游靶标的相互作用。CircKRT75 在 NPC 组织和 NPC 顺铂耐药细胞中明显增强。功能实验表明，circKRT75 沉默抑制 NPC 耐药细胞的生长并促进凋亡。生物信息学筛选鉴定出 circKRT75 作为 miR-659 的分子海绵，而 CCAR2 是 miR-659 的直接靶标。进一步的挽救实验证实，miR-659 抑制剂恢复了 circKRT75 敲低对耐药细胞生长的抑制作用，而 CCAR2 沉默可以逆转 circKRT75 上调对 NPC 顺铂耐药的促进作用。此外，动物实验表明，circKRT75 敲低抑制 NPC 顺铂耐药在体内。CircKRT75 通过 miR-659/CCAR2 信号通路促进 NPC 顺铂耐药，为解决 NPC 化疗耐药问题提供了新的视角和方向。
