Conclusion
Sele is a potential miR-21 target. The opposing Sele levels at mRNA and protein suggest a feedback-regulation from protein to mRNA. The feedback-regulation in miR-21-suppressed gene expression indicates that we should carefully evaluate any data from mRNA array since they may not reflect real protein expression status.
Material and methods
Cancer immune-related 786 mRNA expression was compared in lung tissue from wild-type and miR-21 knock-in mice using NanoString technology. The significantly changed genes were verified using real-time PCR. E-Selectin (Sele) was subsequently identified for further examination using immunohistochemistry (IHC) and Western blot in the same lung tissue. The mouse Sele 3'untranslated region (3'-UTR) was searched to identify a miR-21 matching sequence. The Sele level in miR-21 mimic transfected mouse lung bronchial epithelial (LBE) cells was examined.
Methods
Cancer immune-related 786 mRNA expression was compared in lung tissue from wild-type and miR-21 knock-in mice using NanoString technology. The significantly changed genes were verified using real-time PCR. E-Selectin (Sele) was subsequently identified for further examination using immunohistochemistry (IHC) and Western blot in the same lung tissue. The mouse Sele 3'untranslated region (3'-UTR) was searched to identify a miR-21 matching sequence. The Sele level in miR-21 mimic transfected mouse lung bronchial epithelial (LBE) cells was examined.
Purpose
To study whether miR-21, an oncogene associated with lung tumorigenesis, affects immune response. Material and
Results
We unexpectedly found that the Sele mRNA level significantly increased but the protein level significantly decreased in the lung tissue of miR-21 knock-in mice compared to the mRNA/protein levels in the lung tissue of wild-type mice. The mouse Sele 3'-UTR contains the key sequence that can be targeted by miR-21. The Sele levels decreased in mouse LBE cells after miR-21 mimic transfection.