Chemoresistance poses a significant challenge in the treatment of advanced head and neck squamous cell cancer (HNSCC). The role and mechanism of circular RNAs (circRNAs) in HNSCC chemoresistance remain understudied. We conducted circRNA microarray analysis to identify differentially expressed circRNAs in HNSCC. The expression of circRNAs from the tyrosylprotein sulfotransferase 2 (TPST2) gene and miRNAs was evaluated through qPCR, while the circular structure of circTPST2 was verified using Sanger sequencing and RNase R. Through Western blotting, biotin-labeled RNA pulldown, RNA immunoprecipitation, mass spectrometry, and rescue experiments, we discovered miR-770-5p and nucleolin as downstream targets of circTPST2. Functional tests, including CCK8 assays and flow cytometry, assessed the chemoresistance ability of circTPST2, miR-770-5p, and Nucleolin. Additionally, FISH assays determined the subcellular localization of circTPST2, miR-770-5p, and Nucleolin. IHC staining was employed to detect circTPST2 and Nucleolin expression in HNSCC patients. circTPST2 expression was inversely correlated with cisplatin sensitivity in HNSCC cell lines. Remarkably, high circTPST2 expression correlated with lower overall survival rates in chemotherapeutic HNSCC patients. Mechanistically, circTPST2 reduced chemosensitivity through sponge-like adsorption of miR-770-5p and upregulation of the downstream protein Nucleolin in HNSCC cells. The TCGA database revealed improved prognosis for patients with low circTPST2 expression after chemotherapy. Moreover, analysis of HNSCC cohorts demonstrated better prognosis for patients with low Nucleolin protein expression after chemotherapy. We unveil circTPST2 as a circRNA associated with chemoresistance in HNSCC, suggesting its potential as a marker for selecting chemotherapy regimens in HNSCC patients. Further exploration of the downstream targets of circTPST2 advanced our understanding and improved treatment strategies for HNSCC.
化疗耐药性是晚期头颈部鳞状细胞癌治疗中的重大挑战。环状RNA在头颈部鳞癌化疗耐药中的作用及机制尚不明确。本研究通过circRNA芯片分析筛选头颈部鳞癌中差异表达的circRNA，采用qPCR检测酪氨酰蛋白磺基转移酶2基因来源circRNA及miRNA表达水平，Sanger测序和RNase R实验验证circTPST2的环状结构。通过Western blot、生物素标记RNA pull-down、RNA免疫共沉淀、质谱分析及回复实验，发现miR-770-5p和核仁素是circTPST2的下游靶标。CCK8实验和流式细胞术等功能实验评估circTPST2、miR-770-5p和核仁素的化疗耐药能力，FISH实验确定三者的亚细胞定位，免疫组化染色检测头颈部鳞癌患者组织中circTPST2和核仁素表达。研究显示circTPST2表达水平与头颈部鳞癌细胞系对顺铂的敏感性呈负相关，且高表达circTPST2的化疗患者总体生存率较低。机制上，circTPST2通过海绵吸附miR-770-5p并上调下游核仁素蛋白表达，降低头颈部鳞癌细胞的化疗敏感性。TCGA数据库分析表明低表达circTPST2的化疗患者预后更佳，头颈部鳞癌队列分析显示低表达核仁素蛋白的化疗患者预后更好。本研究首次揭示circTPST2是头颈部鳞癌化疗耐药相关的circRNA，可能作为头颈部鳞癌患者化疗方案选择的标志物，对其下游靶标的深入探索有助于进一步理解头颈部鳞癌耐药机制并优化治疗策略。
肿瘤(癌症)患者之家