MiR-130b/TNF-α/NF-κB/VEGFA loop inhibits prostate cancer angiogenesis

Angiogenesis is a critical biological process essential for solid cancer growth and metastasis. It has been shown that microRNAs (miRNAs) play a vital role in a variety of biological processes in cancers. However, whether miR-130b is involved in prostate cancer angiogenesis remains ill-defined.

We performed the miRNA microarray to analyze miRNA expression in human prostate cancer specimens. In vitro gain-of-function assays and loss-of-function assays were conducted to explore the potential functions of miR-130b in human prostate cancer cells. Correlation analysis and dual-luciferase reporter assay were performed to validate whether tumor necrosis factor-α (TNF-α) was a direct target of miR-130b. The Matrigel plug and tumor vascular imaging assays were performed to confirm the anti-angiogenic activity of miR-130b in nude mice.

We found that miR-130b was one of the miRNAs being most significantly downregulated. Subsequently, we found that miR-130b expression was markedly downregulated in human prostate cancer cell lines. Down-regulation of miR-130b in prostate cancer cells significantly promoted the proliferation, invasion and tubule formation of human umbilical vein endothelial cells (HUVECs), while ectopic expression of miR-130b blocked prostate cancer angiogenesis in vitro and in vivo. Mechanistic analyses indicated that tumor necrosis factor-α (TNF-α) was regulated by miR-130b directly. MiR-130b attenuated nuclear factor-κB (NF-κB) signaling and its downstream gene vascular endothelial growth factor-A (VEGFA) by directly inhibiting TNF-α expression. Additionally, subsequent investigations identified that the ectopic level of VEGFA markedly abrogated the anti-angiogenic effect induced by miR-130b. Interestingly, VEGFA could in turn decrease the expression of miR-130b, thus forming a negative feedback loop that drives the angiogenesis of prostate cancer.

These findings show that miR-130b/TNF-α/NF-κB/VEGFA feedback loop is significantly correlated with angiogenesis in prostate cancer and miR-130b could be regarded as potential therapeutic target for prostate cancer anti-angiogenesis treatment.