title: Clusterin is a gene-specific target of microRNA-21 in head and neck squamous cell carcinoma.
abstract: OBJECTIVE
  MicroRNA-21 (miRNA-21) has proto-oncogenic properties, although no miRNA-21-specific targets have been found in head and neck squamous cell carcinoma (HNSCC). Further study of miRNA-21 and its specific targets is essential to understanding HNSCC biology.
  
  
  METHODS
  miRNA expression profiles of 10 HNSCCs and 10 normal mucosa samples were investigated using a custom miRNA microarray. Thirteen HNSCCs and five normal mucosa primary tissue specimens underwent mRNA expression microarray analysis. To identify miRNA-21 downstream targets, oral keratinocyte cells were subjected to microarray analysis after miRNA-21 transient transfection. miRNA and mRNA expression were validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in a separate cohort of 16 HNSCCs and 15 normal mucosal samples. Microarray and bioinformatics analyses were integrated to identify potential gene targets. In vitro assays looked at the function and interaction of miRNA-21 and its specific gene targets.
  
  
  RESULTS
  miRNA-21 was upregulated in HNSCCs and stimulated cell growth. Integrated analyses identified Clusterin (CLU) as a potential miRNA-21 gene target. CLU was downregulated after forced expression of miRNA-21 in normal and HNSCC cell lines. The activity of a luciferase construct containing the 3'-untranslated region (UTR) of CLU was repressed by the ectopic expression of miRNA-21. CLU was also downregulated in primary HNSCCs and correlated with miRNA-21 overexpression. CLU variant 1 (CLU-1) was the predominant splice variant in HNSCCs and showed growth suppression function that was reversed by miRNA-21 overexpression.
  
  
  CONCLUSIONS
  CLU is a specific, functional target of oncogenic miRNA-21 in HNSCCs. CLU-1 isoform is the predominant growth-suppressive variant targeted by miRNA-21.
authors: Authors' Affiliations: Departments of Otolaryngology-Head and Neck Surgery and Pathology, Johns Hopkins Medical Institutions; The Milton J Dance, Jr. Head and Neck Center, Greater Baltimore Medical Center, Baltimore, Maryland; Department of Basic Oncology, Oncology Institute, Istanbul University, Istanbul, Turkey; and Asuragen, Inc. Austin, Texas.
authors: Wojciech
authors: W
authors: Mydlarz
authors: Mamoru
authors: M
authors: Uemura
authors: Sun
authors: S
authors: Ahn
authors: Patrick
authors: P
authors: Hennessey
authors: Steven
authors: S
authors: Chang
authors: Semra
authors: S
authors: Demokan
authors: Wenyue
authors: W
authors: Sun
authors: Chunbo
authors: C
authors: Shao
authors: Justin
authors: J
authors: Bishop
authors: Julie
authors: J
authors: Krosting
authors: Elizabeth
authors: E
authors: Mambo
authors: William
authors: W
authors: Westra
authors: Patrick
authors: P
authors: Ha
authors: David
authors: D
authors: Sidransky
authors: Joseph
authors: J
authors: Califano
mesh_terms: D020413:3' Untranslated Regions; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism*; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D051152:Clusterin / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006258:Head and Neck Neoplasms / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D034622:RNA Interference; D000077195:Squamous Cell Carcinoma of Head and Neck
chemical_list: D020413:3' Untranslated Regions; C495242:CLU protein, human; D051152:Clusterin; C524940:MIRN21 microRNA, human; D035683:MicroRNAs