MicroRNA-624-mediated ARRDC3/YAP/HIF1α axis enhances esophageal squamous cell carcinoma cell resistance to cisplatin and paclitaxel

Development of chemoresistance remains a major challenge in treating patients suffering from esophageal squamous cell carcinoma (ESCC), despite treatment advances. MicroRNAs (miRNAs) have been shown to play critical roles in the regulation of ESCC cell chemoresistance. Here, we aimed to investigate the role of miR-624 in ESCC and its molecular mechanism in mediating the resistance of ESCC cells to two common chemotherapeutic drugs, cisplatin (CIS) and paclitaxel (PT). Expression patterns of miR-624, arrestin domain-containing 3 (ARRDC3), Yes-associated protein (YAP), and hypoxia-inducible factor-1α (HIF1α) in ESCC tissues and cell lines were identified using RT-qPCR and Western blot analysis. The binding affinities with the miR-624/ARRDC3/YAP/HIF1α axis were characterized. The chemotherapy-sensitive cell line KYSE150 and chemotherapy-resistant cell line KYSE410 were transfected with an overexpression plasmid or shRNA to study the effect of miR-624/ARRDC3/YAP/HIF1α axis on ESCC cell resistance to CIS and PT. Their <i>in vivo</i> effects on resistance to PT were assessed in tumor-bearing nude mice. High expression of miR-624, YAP and HIF1α, and low expression of ARRDC3 were observed in ESCC tissues and cell lines. miR-624 presented with higher expression in KYSE410 than in KYSE150 cells. miR-624 downregulated ARRDC3 to increase YAP and HIF1α expression so as to enhance ESCC cell resistance to CIS and PT <i>in vitro</i> and <i>in vivo</i>. Taken together, these data indicate an important role for miR-624 in promoting the chemoresistance of ESCC cells, highlighting a potential strategy to overcome drug resistance in ESCC treatment. miR-624 targets ARRDC3 to inhibit its expression, and consequently upregulates YAP expression by inhibiting degradation of YAP. By this mechanism, HIF1α expression is upregulated and the HIF1α signaling pathway is activated. ESCC cell chemotherapy resistance is eventually increased.

尽管治疗领域已取得进展，食管鳞状细胞癌（esophageal squamous cell carcinoma, ESCC）患者的临床治疗仍面临化疗耐药发生这一重大难题。微小RNA（microRNAs, miRNAs）已被证实可在食管鳞状细胞癌细胞的化疗耐药调控中发挥关键作用。本研究旨在探讨miR-624在食管鳞状细胞癌中的作用，及其介导食管鳞状细胞癌细胞对两种常用化疗药物——顺铂（cisplatin, CIS）与紫杉醇（paclitaxel, PT）产生耐药性的分子机制。
研究人员通过逆转录实时定量聚合酶链式反应（RT-qPCR）与蛋白质印迹法（Western blot），检测了miR-624、含arrestin结构域蛋白3（arrestin domain-containing 3, ARRDC3）、Yes相关蛋白（Yes-associated protein, YAP）以及缺氧诱导因子-1α（hypoxia-inducible factor-1α, HIF1α）在食管鳞状细胞癌组织与细胞系中的表达模式，并对miR-624/ARRDC3/YAP/HIF1α信号轴的结合亲和力进行了表征。
本研究将化疗敏感细胞系KYSE150与化疗耐药细胞系KYSE410分别转染过表达质粒或短发卡RNA（shRNA），以探究miR-624/ARRDC3/YAP/HIF1α信号轴对食管鳞状细胞癌细胞顺铂与紫杉醇耐药性的影响；同时通过裸鼠荷瘤模型，评估了该信号轴在体内对紫杉醇耐药性的调控作用。
实验结果显示，食管鳞状细胞癌组织与细胞系中miR-624、YAP与HIF1α呈高表达，而ARRDC3呈低表达；且KYSE410细胞中miR-624的表达水平显著高于KYSE150细胞。体外实验证实，miR-624通过下调ARRDC3的表达，升高YAP与HIF1α的蛋白表达水平，进而增强食管鳞状细胞癌细胞对顺铂与紫杉醇的耐药性，该效应在体内裸鼠模型中同样得到验证。
综上，本研究数据表明miR-624在促进食管鳞状细胞癌细胞化疗耐药中发挥重要作用，为克服食管鳞状细胞癌治疗中的药物耐药性提供了潜在干预策略。具体机制为：miR-624可靶向结合ARRDC3并抑制其表达，进而通过抑制YAP的降解上调其表达水平；通过该通路，HIF1α的表达被上调并激活HIF1α信号通路，最终加剧食管鳞状细胞癌细胞的化疗耐药性。