lncRNA JPX通过miR-1301-3p/PIK3R2介导的自噬通路促进鼻咽癌放射抵抗

文献信息

中文摘要

背景： 鼻咽癌（NPC）是一种具有高度转移潜能的侵袭性头颈部恶性肿瘤。放射抵抗仍是与不良预后相关的主要治疗障碍。尽管长链非编码RNA（lncRNA）JPX已在多种癌症中被提及，但其在鼻咽癌放射抵抗中的具体作用仍需进一步阐明。本研究旨在探究JPX是否通过自噬调控调节放射敏感性，并阐明其潜在的分子机制。
方法： 在鼻咽癌细胞系和癌症基因组图谱（TCGA）数据集中分析JPX表达，并通过细胞组分分离确定其亚细胞定位。采用短发夹RNA（shRNA）介导的敲低在CNE-2和HONE-1细胞系中进行功能表征。通过临床相关辐射剂量下的克隆形成存活实验评估放射敏感性，并以MTT评估细胞活力作为筛选指标，同时通过Western blot分析LC3-II和p62评估自噬活性。采用双荧光素酶报告基因和RNA免疫沉淀（RIP）实验验证分子相互作用。
结果： JPX在头颈部鳞状细胞癌（HNSCC）组织和鼻咽癌细胞系中显著上调，主要定位于细胞质。TCGA-HNSCC队列中的临床关联分析显示，JPX表达升高与晚期肿瘤分期和较差的总生存期相关，尽管鼻咽癌特异性的临床验证仍有待建立。基因沉默JPX可减弱自噬流并增强放射敏感性。机制研究揭示，JPX作为竞争性内源RNA（ceRNA）与miR-1301-3p功能性结合，从而减轻miR-1301-3p对PIK3R2的抑制，进而激活促生存自噬通路。
结论： 研究结果表明，JPX通过涉及miR-1301-3p/PIK3R2/自噬调控轴的ceRNA机制促进鼻咽癌放射抵抗。因此，JPX/miR-1301-3p/PIK3R2轴成为放射增敏的潜在机制候选；然而，这一观点仍严格属于初步性质，在可证明任何转化考虑合理之前，需要在经过认证的鼻咽癌模型、体内系统和患者来源样本中进行严格验证。尽管本文承认了细胞系局限性，我们的发现为理解JPX介导的放射抵抗提供了机制框架，值得在更具生理相关性的模型中进一步研究。

英文摘要

BACKGROUND: Nasopharyngeal carcinoma (NPC) represents an aggressive head and neck malignancy with high metastatic potential. Radioresistance remains a major therapeutic obstacle associated with poor prognosis. Although the long non-coding RNA (lncRNA) JPX has been implicated in various cancers, its specific role in NPC radioresistance requires further elucidation. This study aimed to investigate whether JPX modulates radiosensitivity through autophagy regulation and to delineate the underlying molecular mechanisms.
METHODS: JPX expression was analyzed in NPC cell lines and The Cancer Genome Atlas (TCGA) datasets, with subcellular localization determined through cellular fractionation. Functional characterization was performed using short hairpin RNA (shRNA)-mediated knockdown in CNE-2 and HONE-1 cell lines. Radiosensitivity was evaluated by clonogenic survival assays at a clinically relevant radiation dose, with cell viability assessed by MTT as a screening measure. while autophagy activity was assessed through Western blot analysis of LC3-II and p62. Molecular interactions were validated using dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.
RESULTS: JPX was significantly upregulated in head and neck squamous cell carcinoma (HNSCC) tissues and NPC cell lines, showing predominant cytoplasmic localization. Clinical association analysis in the TCGA-HNSCC cohort revealed that elevated JPX expression correlated with advanced tumor stage and poor overall survival, although NPC-specific clinical validation remains to be established. Genetic silencing of JPX attenuated autophagic flux and enhanced radiosensitivity. Mechanistic investigations revealed that JPX functions as a competitive endogenous RNA (ceRNA) functionally associating with miR-1301-3p, thereby alleviating miR-1301-3p-mediated repression of PIK3R2 and subsequently activating pro-survival autophagy pathways.
CONCLUSIONS: The findings demonstrate that JPX promotes radioresistance in NPC through a ceRNA mechanism involving the miR-1301-3p/PIK3R2/autophagy regulatory axis. The JPX/miR-1301-3p/PIK3R2 axis thus emerges as a potential mechanistic candidate for radiosensitization; however, this notion remains strictly provisional and requires rigorous validation in authenticated NPC models, in vivo systems, and patient-derived samples before any translational consideration can be justified. Despite the cell line limitations acknowledged herein, our findings provide a mechanistic framework for understanding JPX-mediated radioresistance that warrants further investigation in more physiologically relevant models.