The role of neopterin in cross-talk between tumor and tumor microenvironment in hepatocellular carcinoma

Abstract

Neopterin is a marker of activated immune response, but its role in hepatocarcinogenesis is unknown. The present study aims to evaluate the effects of neopterin on prooncogenic/proinflammatory, apoptotic pathways, and other molecular mechanisms in HCC. We used SNU449, Huh-7, SK-Hep-1, and HepG2 cell lines. A cell viability assay was performed with different concentrations of neopterin. RT-PCR, Western blotting, transwell migration, scratch assay, and reactive oxygen species (ROS) production assays were performed at inhibition concentration 50 of neopterin, which was 40 µM for SNU449 and 80 µM for other cell lines. There were significant changes in mTOR, STAT3, PI3K, and interleukin-6 gene expressions, which were also supported by the protein expressions. Neopterin did not affect apoptosis in SNU449, while apoptosis increased by all doses of neopterin in SK-Hep-1 and HepG2. ROS production was increased in all cell lines in response to neopterin. Cell migration was reduced in SK-Hep1 and HepG2 but did not change in SNU449 and Huh-7. Our study showed that neopterin is not just a byproduct. The results suggest that neopterin may be a paracrine factor that modulates pro-inflammatory and pro-oncogenic pathways responsible for the biological behavior of HCC in a chronic inflammatory tumor microenvironment.

Keywords

• hepatocellular carcinoma
• tumor microenvironment
• neopterin