Intercellular Interactions Mediated by HGF And TGF- Promote the 3D Spherical and Xenograft Growth of Liver Cancer Cells

Background: Recently, the importance of the interactions between liver cancer cells and fibroblasts has been increasingly recognized; however, many details remain to be explored. Methods: In this work, we first studied their intercellular interactions using conditioned medium from mouse embryonic fibroblasts (MEFs), then through a previously established coculture model. Results: Culturing in a conditioned medium from MEFs could significantly increase the growth, migration, and invasion of liver cancer cells. The coculture model further demonstrated that a positive feedback loop was formed between transforming growth factor-β (TGF-β) from HepG2 cells and mHGF (mouse hepatocyte growth factor) from MEFs during coculture. In this feedback loop, c-Met expression in HepG2 cells was significantly increased, and its downstream signaling pathways, such as Src/FAK, PI3K/AKT, and RAF/MEK/ERK, were activated. Moreover, the proportion of activated MEFs was also increased. More importantly, the growth-promoting effects caused by the interaction of these two cell types were validated in vitro by a 3D spheroid growth assay and in vivo by a xenograft mouse model. Conclusion: Collectively, these findings provide valuable insights into the interactions between fibroblasts and liver cancer cells, which may have therapeutic implications for the treatment of liver cancer.