Data from Downregulation of miR-138 Sustains NF-κB Activation and Promotes Lipid Raft Formation in Esophageal Squamous Cell Carcinoma

Abstract

<div>Abstract<p><b>Purpose:</b> 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.</p><p><b>Experimental Design:</b> 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 <i>in vitro</i> kinase, electrophoretic mobility shift, lipid raft isolation, and luciferase reporter assays.</p><p><b>Results:</b> 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 <i>in vitro</i> and <i>in vivo</i>. 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 <i>in vitro</i> analysis was consistent with a significant inverse correlation between miR-138 expression and NF-κB hyperactivation in a cohort of human ESCC specimens.</p><p><b>Conclusion:</b> 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. <i>Clin Cancer Res; 19(5); 1083–93. ©2013 AACR</i>.</p></div>