Figure 8. The proposed model illustrated the role of hsa_circ_0110102/miR-580-5p/PPARα/CCL2 signaling in regulating HCC metastasis. hsa_circ_0110102 was downregulated in patients with HCC and metastasis or recurrence and bound to miR-580-5p, which targeted PPARα 3′ UTR to down-regulate its expression level, and increased the synthesis and secretion of CCL2 from HCC cells to tumor microenvironment. CCL2 activate the COX-2/PGE2 pathway in macrophage via FoxO1 in a p38 MAPK-dependent manner, which increased the proliferation and invasion of HCC cells.