2336P - MiR-155 overexpression regulates epithelial-mesenchymal transition through repressing Quaking in lung cancer cells

Background

Epithelial-mesenchymal transition (EMT) is one of the major molecular mechanisms inducing tumor invasion and metastasis. Various MicroRNAs (miRNAs) have been shown to be involved in EMT. MiR-155 is consistently up-regulated in non-small cell lung cancer and is associated with poor overall survival. Whether miR-155 regulates EMT in lung cancer cells remains unclear.

Methods

We first transfected plasmid containing miR-155 into H1299 and A549 cells and established H1299-miR-155 and A549-miR-155 cells. Western blotting was done to demonstrate E-cadherin, vimentin, and Quaking (QKI) expression in H1299-miR-155 and A549-miR-155 cells. Invasion and migration assay were performed in H1299-miR-155 and A549-miR-155 cells. We then constructed p-mcherry plasmids that contain miR-155 and a p-Luc-QKI-3’UTR reporter plasmid. Luciferase assay was done to demonstrate whether miR-155 binds to the QKI 3’UTR.

Results

Quantitative RT-PCR showed that QKI expression was downregulated in H1299-miR-155 and A549-miR-155 cells. Western Blotting showed decreased E-cadherin and increased vimentin expression in H1299 and A549 cells after miR-155 transfection. Western blotting also showed decreased QKI expression in H1299 and A549 cells after miR-155 transfection. Migration assay showed that the number of migrated cells significantly increased after miR-155 transfection in H1299 and A549 cells. Invasion assay showed that the number of invaded cells also significantly increased after miR-155 transfection in H1299 and A549 cells. We constructed p-mcherry plasmids that contain miR-155 and a p-Luc-QKI-3’UTR reporter plasmid. Luciferase assay showed that miR-155 represses the activity of p-Luc-QKI-3’UTR. We then mutated the miR-155 binding site in the QKI 3’UTR to confirm that repression of the mRNA levels is induced by the binding of miR-155 to the QKI 3’UTR.

Conclusions

MiR-155 overexpression regulates EMT through repressing QKI in lung cancer cells. Repression of QKI is induced by the binding of miR-155 to the QKI 3’UTR.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The author.

Funding

Has not received any funding.

Disclosure

The author has declared no conflicts of interest.