miR-26a/b Inhibit Tumor Growth and Angiogenesis by Targeting the HGF-VEGF Axis in Gastric Carcinoma.

BACKGROUND/AIMS: Abnormal expression of HGF is found in various cancers and correlates with tumor proliferation, metastasis and angiogenesis. However, the regulatory mechanism of the HGF-VEGF axis remains unclear.

METHODS: The expression characteristic of HGF in human gastric cancer tissues was shown by an immunohistochemistry assay, and the expression levels of target protein were detected by Western blot. The relative levels of miR-26a/b and target mRNA were examined by qRT-PCR. We used bioinformatics tools to search for miRNAs that can potentially target HGF. A luciferase assay was used to confirm direct targeting. Furthermore, the functions of miR-26a/b and HGF were evaluated by cell proliferation and migration assays in vitro and by the mouse xenograft tumor model in vivo.

RESULTS: We found that the HGF protein was clearly increased while miR-26a/b were dramatically down-regulated in gastric cancer. miR-26a/b directly bind to the 3'-UTR of HGF mRNA at specific targeting sites. We demonstrated that the repression of the HGF-VEGF pathway by miR-26a/b overexpression suppressed gastric cancer cell proliferation and migration. Furthermore, miR-26a/b also showed an anti-tumor effect in the xenograft mouse model by suppressing tumor growth and angiogenesis.

CONCLUSIONS: miR-26a/b could suppress tumor tumorigenesis and angiogenesis by targeting the HGF-VEGF axis and could serve as a potential treatment modality for targeted therapy in the clinical treatment of gastric cancer.