The roles of C-C motif ligand 11 (CCL11) in hepatocellular carcinoma recurrence after liver surgery

Abstract

Background & aims Liver surgery is the primary curative treatment for patients with early-stage hepatocellular carcinoma (HCC). The major challenge is the high recurrence rate, but currently, without effective prognostic and preventive regimens, rendering the main cause of poor prognosis. One of the uncertain risk factors involves the significant release of cytokines induced by surgery, with certain cytokines having profound impacts on the hepatic microenvironment and influencing the probability of tumor relapse. This study aimed to elucidate the effects and mechanisms of a surgery-induced chemokine, C-C motif ligand 11 (CCL11), on post-surgery HCC recurrence, with the goal of establishing novel predictive and preventive strategies. Methodology The first part involved quantifying the hepatic and post-operative circulating levels of CCL11 in HCC patients. The clinical significance and prognostic value of CCL11 in predicting post-operative HCC recurrence and survival were assessed. An integrated predictive model for HCC recurrence was developed by combining post-operative circulating CCL11 with clinical factors. The second part encompassed functional and mechanistic investigations of CCL11 in immunoregulatory cells and HCC cells. Cellular, bioinformatic, and transcriptomic experiments were conducted to elucidate the roles of CCL11 in modulating CCR5+M2-like macrophages and their effector immune cells. Furthermore, the functions and mechanisms of CCL11 in regulating HCC progression were characterized by in vitro and in vivo experiments. Finally, the therapeutic potential of inhibiting CCL11 was evaluated by a mouse surgical resection of orthotopic HCC model. Results Upregulation of circulating CCL11 after hepatectomy was significantly associated with post-operative HCC recurrence and poor survival. A high post-operative CCL11 was an independent prognostic factor of HCC recurrence. The integrated prediction model combining post-operative CCL11 and clinical factors enhanced the prediction accuracy for HCC recurrence. CCL11 was determined to be predominantly secreted from myofibroblasts upon acute hepatic injury. Upregulation of CCL11 in HCC non-tumor tissues was significantly associated with post-resection tumor recurrence and poor survival. Upregulation of hepatic CCL11 was significantly associated with high infiltration of CCR5+M2-like macrophages in hepatic immune microenvironment, whose augment was significantly associated with poor prognosis of patients after liver resection. Administration of recombinant CCL11 protein could enhance the activation of immunosuppressive CCR5+M2-like macrophages to increase the secretion of MCP-1 and IL8 and functionally enhance Treg induction from naïve CD4+T. CCL11 could activate the IKK/IkB/NFkB1 pathway in CCR5+M2-like macrophages to upregulate PD-L1 expression. Meanwhile, administration of recombinant CCL11 protein promoted the migration and invasion of HCC cells via CCR3-mediated PI3K/AKT/MafK/MMP13 pathway. The in vivo orthotopic HCC model validated that CCL11 could promote HCC growth and metastasis by activating PI3K/AKT/MafK/MMP13 axis. Importantly, the mouse HCC resection model demonstrated that anti-CCL11 treatment after hepatectomy effectively reduced tumor recurrence and prolonged the survival of mice, attributed to suppressing the infiltration of immunosuppressive CCR5+M2-like macrophages and the levels of MMP13 in hepatic microenvironment. Conclusions CCL11 is a non-invasive and functional biomarker for HCC recurrence after liver surgery. Liver surgery-induced upregulation of CCL11 drives an immunosuppressive hepatic microenvironment (“Soil”）and promotes the progressiveness of HCC cells (“Seed”), leading to an increased risk of tumor recurrence after liver surgery.