State Key Laboratory of Oncology in Southern China, Department of Experimental Research, Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, China.
Clin Cancer Res. 2013 Mar 1;19(5):1083-93. doi: 10.1158/1078-0432.CCR-12-3169. Epub 2013 Jan 14.
Constitutive activation of NF-κB signaling plays vital roles in esophageal squamous cell carcinoma (ESCC) progression. The aim of this study was to evaluate the effect of miR-138 on NF-κB activation and ESCC progression.
Expression of miR-138 in ESCC cell lines, ESCC tissues, and 205 archived ESSC specimens was determined using real-time PCR analysis. Anchorage-independent growth, chicken chorioallantoic membrane, Transwell matrix invasion and Annexin V-binding assays, and a xenograft tumor model were used to determine the role of miR-138 in ESCC progression. The effect of miR-138 on NF-κB activation was investigated using IKK in vitro kinase, electrophoretic mobility shift, lipid raft isolation, and luciferase reporter assays.
miR-138 was downregulated and inversely correlated with tumor progression and patient survival in ESCCs. Downregulation of miR-138 enhanced, whereas upregulation of miR-138 reduced, the aggressive phenotype of ESCC cells both in vitro and in vivo. Silencing miR-138 promoted K63-linked polyubiquitination of the NF-κB signaling intermediaries TRAF2 and RIP1 and sustained NF-κB activation. Furthermore, downregulation of miR-138 induced lipid raft formation via upregulating multiple components of lipid rafts, including FLOT1, FLOT2, and caveolin-1. Importantly, the in vitro analysis was consistent with a significant inverse correlation between miR-138 expression and NF-κB hyperactivation in a cohort of human ESCC specimens.
Our results show that miR-138 functions as a tumor-suppressive miRNA and that downregulation of miR-138 contributes to constitutive NF-κB activation and ESCC progression.
NF-κB 信号的组成性激活在食管鳞状细胞癌（ESCC）进展中发挥着重要作用。本研究旨在评估 miR-138 对 NF-κB 激活和 ESCC 进展的影响。
使用实时 PCR 分析确定 miR-138 在 ESCC 细胞系、ESCC 组织和 205 个存档的 ESCC 标本中的表达。使用非依赖性生长、鸡绒毛尿囊膜、Transwell 基质侵袭和 Annexin V 结合测定以及异种移植肿瘤模型来确定 miR-138 在 ESCC 进展中的作用。使用体外激酶 IKK、电泳迁移率变动、脂质筏分离和荧光素酶报告基因测定来研究 miR-138 对 NF-κB 激活的影响。
miR-138 在 ESCC 中下调，与肿瘤进展和患者生存呈负相关。miR-138 的下调增强了 ESCC 细胞的侵袭表型，而上调 miR-138 则降低了 ESCC 细胞的侵袭表型，无论是在体外还是体内。沉默 miR-138 促进了 NF-κB 信号转导中间物 TRAF2 和 RIP1 的 K63 连接多泛素化，并维持 NF-κB 的激活。此外，miR-138 的下调通过上调多个脂质筏成分，包括 FLOT1、FLOT2 和 caveolin-1，诱导了脂质筏的形成。重要的是，在一组人类 ESCC 标本中，体外分析与 miR-138 表达与 NF-κB 过度激活之间存在显著的负相关。
我们的结果表明，miR-138 作为一种肿瘤抑制 miRNA 发挥作用，miR-138 的下调导致 NF-κB 的组成性激活和 ESCC 的进展。
