2'-Hydroxyflavanone inhibits bladder cancer cell proliferation and angiogenesis via regulating miR-99a-5p/mTOR signaling.

Abstract

Objectives: 2'-Hydroxyflavanone (2HF) has been recognized for its antitumor potential in recent years. In the past decade, the role of miRNAs in tumors has been gradually explored. Since natural compounds may regulate miRNA networks, our objective is to investigate the potential effects and mechanisms of 2HF in the treatment of bladder cancer (BCa) by targeting miRNAs.

Methods: Cell viability, tube formation, Transwell, western blotting and colony formation assays were used to evaluate the effects of 2HF on the viability and angiogenesis of BCa cells. The expression of miR-99a-5p and mTOR was detected via RT-qPCR and western blotting. A subcutaneous xenograft animal experiment was used to evaluate the tumor inhibition of 2HF in vivo. The binding of miR-99a-5p to mTOR was demonstrated via dual-luciferase reporting and RNA pull-down assays.

Results: 2HF inhibited the cell viability, angiogenesis, protein expression of VEGFa and Ki67 in T24 and 253J cells and protein expression of CD31 in HUVEC cells. Also, 2HF induced the upregulation of miR-99a-5p but the downregulation of mTOR expression. Additionally, the inhibitory effect of 2HF on tumor cells can be effectively rescued by silencing miR-99a-5p or overexpressing mTOR in vitro. Moreover, 2HF inhibited tumor growth in nude mice, in which it upregulated miR-99a-5p but suppressed mTOR expression in xenograft tissues. Mechanistically, miR-99a-5p can directly target the mRNA of mTOR by binding to its 3' untranslated region (3'-UTR) and then inhibiting the expression of mTOR.

Conclusions: 2HF inhibited BCa cell proliferation and angiogenesis by regulating the miR-99a-5p/mTOR/VEGFa axis, which may provide a novel treatment strategy and molecular mechanism for BCa treatment.