MicroRNA-21 regulates the proliferation and invasion in esophageal squamous cell carcinoma.
OBJECTIVE
MicroRNAs are approximately 22 nucleotide noncoding RNA molecules that posttranscriptionally regulate gene expression. The aim of this study was (a) to determine a role of microRNA-21 in esophageal squamous cell carcinoma and (b) to elucidate the regulation of the programmed cell death 4 (PDCD4) gene by microRNA-21.


METHODS
MicroRNA-21 expression was investigated in 20 matched normal esophageal epitheliums and esophageal squamous cell carcinomas and seven esophageal squamous cell carcinoma cell lines (TE6, TE8, TE10, TE11, TE12, TE14, KYSE30) by TaqMan quantitative real-time PCR and in situ hybridization. To evaluate the role of microRNA-21, cell proliferation and invasion were analyzed with anti-microRNA-21-transfected cells. In addition, the regulation of PDCD4 by microRNA-21 was elucidated to identify the mechanisms of this regulation.


RESULTS
Of 20 paired samples, 18 cancer tissues overexpressed microRNA-21 in comparison with matched normal epitheliums. Specifically, patients with lymph node metastasis or venous invasion showed significantly high expression of microRNA-21. In situ hybridization for microRNA-21 showed strong positive staining in paraffin-embedded esophageal squamous cell carcinoma tissues. All seven esophageal squamous cell carcinoma cell lines also overexpressed microRNA-21, and anti-microRNA-21-transfected cells showed significant reduction in cellular proliferation and invasion. The PDCD4 protein levels in esophageal squamous cell carcinoma cells have an inverse correlation with microRNA-21 expression. Anti-microRNA-21-transfected cells increased PDCD4 protein expression without changing the PDCD4 mRNA level and increased a luciferase-reporter activity containing the PDCD4-3' untranslated region construct.


CONCLUSIONS
MicroRNA-21 targets PDCD4 at the posttranscriptional level and regulates cell proliferation and invasion in esophageal squamous cell carcinoma. It may serve as a novel therapeutic target in esophageal squamous cell carcinoma.
Hiyoshi
Yukiharu
Y
Department of Gastroenterological Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Kamohara
Hidenobu
H
Karashima
Ryuichi
R
Sato
Nobutaka
N
Imamura
Yu
Y
Nagai
Youhei
Y
Yoshida
Naoya
N
Toyama
Eiichiro
E
Hayashi
Naoko
N
Watanabe
Masayuki
M
Baba
Hideo
H
D000368:Aged; D000369:Aged, 80 and over; D051017:Apoptosis Regulatory Proteins / Q000032:analysis / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D049109:Cell Proliferation; D004938:Esophageal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D035683:MicroRNAs / Q000032:analysis / Q000502:physiology*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D016601:RNA-Binding Proteins / Q000032:analysis / Q000235:genetics
D051017:Apoptosis Regulatory Proteins; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; C114487:PDCD4 protein, human; D016601:RNA-Binding Proteins