Activation of human hepatic stellate cells enhances the metastatic ability of hepatocellular carcinoma cells via up-regulation of interleukin-1β

Purpose: The purpose was to investigate the effect of activated human hepatic stellate cell (HSC) microenvironment on the metastatic capacity of hepatocellular carcinoma (HCC) cells and its underlying mechanism.

Methods: LX-2 HSCs were stimulated with Human Transforming Growth Factor-Beta 1(TGF-β1), and protein expression of α-smooth muscle actin (α-SMA) and filamentous actin (F-actin) were determined to verify the activation of LX-2 cells. Next, SMMC7721 HCC cells were cultured in the conditioned medium originating from activated LX-2 cells. Wound healing and Transwell assays were performed to examine cell migration and invasion. The expression of metastasis-related genes Matrix Metalloproteinase9 (MMP9), N-Cadherin, and Vascular endothelial growth factor (VEGF) was detected. ELISA was carried out to determine the interleukin (IL) -1β level. Finally the inhibitors of TGF-β1 and IL-1β were employed to investigate the roles of LX-2 activation and IL-1β in the metastasis-related gene alterations.

Results: TGF-β1 activated LX-2 cells, as evidenced by up-regulated α-SMA and F-actin expression. Compared with the control medium, the conditioned medium derived from LX-2 cells significantly promoted the migration and invasion of SMMC7721 cells. And it also up-regulated mRNA and protein expression of the metastasis-related genes in SMMC7721 cells. Furthermore, it resulted in a significant increase in the IL-1β level in SMMC7721 cells. Importantly, TGF-β1 inhibitor and IL-1β inhibitor either individually or synergistically abolished the up-regulated expression of conditioned medium-induced metastasis-related gene in SMMC7721 cells.

Conclusions: The conditioned medium generating from TGF-β1-activated LX2 cells can enhance the metastatic ability of SMMC7721 cells through up-regulating IL-1 expression.