| Autor: |
Phatak P; Birmingham Veterans Affairs Health Care System, Birmingham, AL 35233, USA.; Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35233, USA., Tulapurkar ME; Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA., Burrows WM; Department of Surgery Thoracic Medicine and Surgery, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA., Donahue JM; Birmingham Veterans Affairs Health Care System, Birmingham, AL 35233, USA.; Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35233, USA. |
| Abstrakt: |
MicroRNA (miR)-199a-5p has been shown to function as a tumor suppressor in some malignancies but its role in esophageal cancer is poorly understood. To further explore its role in esophageal cancer, we sought to investigate the interaction between miR-199a-5p and Jun-B, an important component of the AP1 transcription factor, which contains a potential binding site for miR-199a-5p in its mRNA. We found that levels of miR-199a-5p are reduced in both human esophageal cancer specimens and in multiple esophageal cancer cell lines compared to esophageal epithelial cells. Jun-B expression is correspondingly elevated in these tumor specimens and in several cell lines compared to esophageal epithelial cells. Jun-B mRNA expression and stability, as well as protein expression, are markedly decreased following miR-199a-5p overexpression. A direct interaction between miR-199a-5p and Jun-B mRNA was confirmed by a biotinylated RNA-pull down assay and luciferase reporter constructs. Either forced expression of miR-199a-5p or Jun-B silencing led to a significant decrease in cellular proliferation as well as in AP-1 promoter activity. Our results provide evidence that miR-199a-5p functions as a tumor suppressor in esophageal cancer cells by regulating cellular proliferation, partially through repression of Jun B. |
