Antiangiogenic effects of the chemopreventive agent tributyrin, a butyric acid prodrug, during the promotion phase of hepatocarcinogenesis

Abstract Agents that inhibit angiogenic factors may prevent the development of hepatocellular carcinoma (HCC). Thus, the objective of this study was to kinetically evaluate the antiangiogenic activity of tributyrin (TB), a butyric acid prodrug, in the promotion stage of hepatocarcinogenesis. For this purpose, the resistant hepatocyte (RH) model was used for induction of preneoplastic lesions in Wistar rats. During the promotion phase, the animals received TB or maltodextrin (MD) as control daily. The rats were killed at three time-points (P1, P2 and P3). Increased expression of Vegfa and Vegfr2 was observed during promotion phase of hepatocarcinogenesis, which was not reversed by TB treatment. However, TB treatment reduced the expression of cluster of differentiation (CD) 34-positive vessels at P3 and α-smooth muscle actin (α-SMA)-positive vessels at P2 compared with MD. Enhanced levels of hypoxia inducible factor-1α (HIF-1α) and phosphorylated extracellular signal-regulated kinases (pERK) were detected at P3 when compared with P1 and P2 in the MD treatment. TB treatment reduced the levels of HIF-1α and pERK at P3 relative to the MD control. Experiments with human umbilical vein endothelial cells (HUVEC) showed that sodium butyrate (NaBu) inhibited cell migration and tube formation, confirming the antiangiogenic activity of its prodrug TB. In conclusion, antiangiogenic activity of TB is an early event that already occurs in preneoplastic livers, reinforcing its potential chemopreventive effects against HCC. The expressions of angiogenesis factors such as VEGFA, VEGFR2, CD34, α-SMA and HIF-1α, as well as pERK, are already elevated in the early stages of HCC. TB reduced the expression of these factors, which suggests that its chemopreventive effect may involve the modulation of neovascularization during early phases of hepatocarcinogenesis.