miR-375 Regulates Invasion-Related Proteins Vimentin and L-Plastin

• Published in: The American journal of pathology Vol. 187; no. 7; pp. 1523 - 1536
• Main Authors: Jimenez, Lizandra, Lim, Jihyeon, Burd, Berta, Harris, Thomas M, Ow, Thomas J, Kawachi, Nicole, Belbin, Thomas J, Angeletti, Ruth, Prystowsky, Michael B, Childs, Geoffrey, Segall, Jeffrey E
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2017; American Society for Investigative Pathology
• Subjects: Carcinoma, Squamous Cell - genetics; Core Binding Factor Alpha 2 Subunit - genetics; Core Binding Factor Alpha 2 Subunit - isolation & purification; Core Binding Factor Alpha 2 Subunit - metabolism; Down-Regulation; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Head and Neck Neoplasms - genetics; Humans; Microfilament Proteins - genetics; Microfilament Proteins - isolation & purification; Microfilament Proteins - metabolism; MicroRNAs - genetics; Models, Biological; Neoplasm Invasiveness; Neoplasm Proteins - genetics; Neoplasm Proteins - isolation & purification; Neoplasm Proteins - metabolism; Pathology; Proteomics; Regular; Squamous Cell Carcinoma of Head and Neck; Vimentin - genetics; Vimentin - isolation & purification; Vimentin - metabolism
• ISSN: 0002-9440; 1525-2191
• DOI: 10.1016/j.ajpath.2017.02.019

Invasion is a hallmark of advanced head and neck squamous cell carcinoma (HNSCC). We previously determined that low relative miR-375 expression was associated with poor patient prognosis. HNSCC cells with increased miR-375 expression have lower invasive properties and impaired invadopodium activity. Using stable isotope labeling with amino acids in cell culture and reverse-phase liquid chromatography mass spectrometry, we assessed the impact of miR-375 expression on protein levels in UM-SCC-1 cells. Increased miR-375 expression was associated with down-regulation of proteins involved in cellular assembly and organization, death and survival, and movement. Two invasion-associated proteins, vimentin and L-plastin, were strongly down-regulated by miR-375. Luciferase reporter assays demonstrated that high miR-375 expression reduced vimentin promoter activity, suggesting that vimentin is an indirect target of miR-375. Runt-related transcription factor 1 (RUNX1) is a potential miR-375 direct target, and its knockdown reduced vimentin and L-plastin expression. Data in The Cancer Genome Atlas HNSCC database showed a significant inverse correlation between miR-375 expression and RUNX1, vimentin, and L-plastin RNA expression. These clinical correlations validate our in vitro model findings and support a mechanism in which miR-375 suppresses RUNX1 levels, resulting in reduced vimentin and L-plastin expression. Furthermore, knockdown of RUNX1, L-plastin, and vimentin resulted in significant reductions in cell invasion in vitro , indicating the functional significance of miR-375 regulation of specific proteins involved in HNSCC invasion.