S100A9 from tumor-associated macrophage enhances cancer stem cell-like properties of hepatocellular carcinoma (RNA-Seq)

Tumor-associated macrophages (TAMs) are crucial components of the tumor microenvironment (TME). They play vital roles in hepatocellular carcinoma (HCC) progression. However, the interactions between TAMs and HCC cells have not been fully characterized. In this study, TAMs were induced using human monocytic cell line THP-1 cells in vitro to investigate their functions in HCC progression. S100 calcium binding protein A9 (S100A9), an inflammatory microenvironment-related secreted protein, was identified to be significantly upregulated in TAMs. S100A9 expression in tumor tissues was associated with poor survival of HCC patients. It could enhance the stem cell-like properties of HepG2 and MHCC-97H cells by activating nuclear factor-kappa B (NF-?B) signaling pathway through advanced glycosylation end-product specific receptor (AGER) in a Ca2+-dependent manner. Furthermore, we found that, after treatment with S100A9, HepG2 and MHCC-97H cells recruited more macrophages infiltration via chemokine (C-C Motif) ligand 2 (CCL2), which suggests a positive feedback between TAMs and HCC cells. Taken together, our findings reveal that TAMs could upregulate S100A9 and enhance the stem cell-like properties of HCC cells, and provide a potential therapeutic target for combating HCC. Overall design: we used a THP-1 cells-derived TAMs induction experiment system to induce TAMs(co-cultured with HepG2/MHCC-97H cells). The expression levels of TAM markers, IL-10 and CD206, were significantly increased in THP-1 cells-derived macrophages after co-culture with HepG2 cells or MHCC-97H cells. These indicate the successful induction of TAMs. Next, we analyzed the differentially expressed genes in THP-1 cells-derived TAMs using RNA-sequencing (RNA-seq) analysis.