Knockdown of TUG1 by shRNA inhibited renal cell carcinoma formation by miR-299-3p/VEGF axis in vitro and in vivo.

Renal cell carcinoma (RCC) is one of the top ten deadly malignancies in the world. The long non-coding RNA taurine up-regulated gene 1 (TUG1) is a transcript that is up-regulated by taurine. There is ample evidence that TUG1 plays a crucial role in the progression of various cancers. This study aimed to investigate the role of TUG1 in RCC and its underlying molecular mechanisms. In the current study, knockdown of TUG1 by shRNA (sh-TUG1) significantly inhibited proliferation, invasion, migration and EMT processes of ACHN cells and OS-RC-2 cells, and induced apoptosis. Besides, bioinformatics analysis revealed that miR-299-3p is a target of TUG1. TUG1 overexpression (LV-TUG1) significantly inhibited the expression of miR-299-3p, whereas sh-TUG1 showed the opposite effect. Dual luciferase reporter assay further confirmed the targeting relationship between TUG1 and miR-299-3p. In addition, vascular endothelial growth factor (VEGFA) is a target of miR-299-3p. Knockdown of VEGFA (si-VEGFA) significantly inhibited the proliferation and motility of ACHN cells, and induced apoptosis. RT-qPCR results showed that sh-TUG1 similarly inhibited VEGFA expression. Further functional analysis indicated that sh-TUG1 inhibited tumorigenesis by down-regulating VEGFA levels. However, LV-TUG1 showed the opposite effects. Furthermore, animal experiments have shown that sh-TUG1 inhibited tumor growth and metastasis and induces apoptosis in vivo. These results indicate that sh-TUG1 inhibited renal cell carcinoma formation by miR-299-3p/VEGF axis in vitro and in vivo. Taken together, all of these results reveal a novel mechanism of TUG1 in RCC tumorigenesis, suggesting that targeted drugs for TUG1 provides a new direction for the treatment of RCC.