Department of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, 833, Taiwan.
Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyüan, 33302, Taiwan.
J Exp Clin Cancer Res. 2022 Jul 1;41(1):215. doi: 10.1186/s13046-022-02415-0.
Leptin is important in physiological and pathological functions in various cancers, however, the significance and mechanisms of leptin in nasopharyngeal carcinoma remain ambiguous.
Leptin expression was analyzed by QPCR, immunohistochemistry, Western blotting, and TCGA database. The impact of gain- or loss-of-function of leptin were determined by MTT, colony formation, wound healing, and Transwell assays in NPC cells, and by a xenograft tumor model. Leptin-modulated glucose consumption and lactate production were assessed by ELISA. Furthermore, leptin-regulated signaling pathways were examined by QPCR and Western blotting assays. The immunoprecipitation assay was conducted to determine interaction between leptin and EGFR. In addition, miR-874-3p-regulated leptin expression was evaluated using bioinformatics, QPCR, luciferase assay, AGO2-RIP assay, and Western blotting.
In this study, we found that leptin was highly expressed in the sera and tumor tissues of patients with NPC, and elevated leptin expression was associated with advanced clinical features and poor prognosis. Functional assays demonstrated that leptin remarkably promoted NPC cell growth, motility, and glycolysis in vitro and in vivo. Mechanistically, leptin associated with EGFR, resulting in enhanced cell growth through the regulation of cell-cycle related markers, glycolysis-related genes, and EGFR/AKT/c-Myc signaling. Moreover, leptin potentiated the invasive capacity of NPC cells by promoting EMT. We further explored that miR-874-3p influenced leptin-mediated NPC progression. Overexpression of miR-874-3p prevented cell growth, motility, glucose consumption, and lactate production in NPC cells, whereas miR-874-3p inhibition had the opposite effects. AGO-RIP assays confirmed that Argonaute 2 (AGO2), a protein associated with miR-874-3p, regulated leptin expression in NPC cells. The rescue assays indicated that inhibition of leptin suppressed the effects of miR-874-3p inhibitor. In clinical specimens, miR-874-3p was negatively correlated with leptin.
Leptin may serve as a novel prognostic factor and potential therapeutic target for patients with NPC. In addition, a newly discovered regulatory axis of leptin/EGFR/AKT/c-Myc can provide a novel therapeutic strategy for NPC.
瘦素在各种癌症的生理和病理功能中都很重要，然而，瘦素在鼻咽癌中的意义和机制仍不清楚。
通过 QPCR、免疫组织化学、Western blot 和 TCGA 数据库分析瘦素表达。在 NPC 细胞中，通过 MTT、集落形成、划痕愈合和 Transwell 测定以及异种移植肿瘤模型，确定瘦素的增益或缺失功能的影响。通过 ELISA 评估瘦素调节的葡萄糖消耗和乳酸产生。此外，通过 QPCR 和 Western blot 测定检查瘦素调节的信号通路。通过免疫沉淀测定确定瘦素与 EGFR 之间的相互作用。另外，通过生物信息学、QPCR、荧光素酶测定、AGO2-RIP 测定和 Western blot 评估 miR-874-3p 调节瘦素表达。
在这项研究中，我们发现瘦素在 NPC 患者的血清和肿瘤组织中高度表达，并且升高的瘦素表达与晚期临床特征和不良预后相关。功能测定表明，瘦素在体外和体内显著促进 NPC 细胞的生长、迁移和糖酵解。机制上，瘦素与 EGFR 相关，通过调节细胞周期相关标志物、糖酵解相关基因和 EGFR/AKT/c-Myc 信号来增强细胞生长。此外，瘦素通过促进 EMT 增强 NPC 细胞的侵袭能力。我们进一步研究了 miR-874-3p 对瘦素介导的 NPC 进展的影响。miR-874-3p 的过表达可防止 NPC 细胞的生长、迁移、葡萄糖消耗和乳酸产生，而 miR-874-3p 的抑制则产生相反的效果。AGO-RIP 测定证实 Argonaute 2（AGO2），一种与 miR-874-3p 相关的蛋白质，调节 NPC 细胞中的瘦素表达。挽救测定表明，抑制瘦素可抑制 miR-874-3p 抑制剂的作用。在临床标本中，miR-874-3p 与瘦素呈负相关。
瘦素可能成为 NPC 患者的新型预后因子和潜在治疗靶标。此外，新发现的瘦素/EGFR/AKT/c-Myc 调节轴可为 NPC 提供新的治疗策略。
