Abstract
Hepatocellular carcinoma, a deadly disease, commonly arises in the setting of chronic inflammation. C-C motif chemokine ligand 2 (CCL2/MCP1), a chemokine that recruits CCR2-positive immune cells to promote inflammation, is highly upregulated in hepatocellular carcinoma patients. Here, we examined the therapeutic efficacy of CCL2-CCR2 axis inhibitors against hepatitis and hepatocellular carcinoma in the miR-122 knockout (a.k.a. KO) mouse model. This mouse model displays upregulation of hepatic CCL2 expression, which correlates with hepatitis that progress to hepatocellular carcinoma with age. Therapeutic potential of CCL2-CCR2 axis blockade was determined by treating KO mice with a CCL2-neutralizing antibody (nAb). This immunotherapy suppressed chronic liver inflammation in these mice by reducing the population of CD11highGr1+ inflammatory myeloid cells and inhibiting expression of IL6 and TNFα in KO livers. Furthermore, treatment of tumor-bearing KO mice with CCL2 nAb for 8 weeks significantly reduced liver damage, hepatocellular carcinoma incidence, and tumor burden. Phospho-STAT3 (Y705) and c-MYC, the downstream targets of IL6, as well as NF-κB, the downstream target of TNFα, were downregulated upon CCL2 inhibition, which correlated with suppression of tumor growth. In addition, CCL2 nAb enhanced hepatic NK-cell cytotoxicity and IFNγ production, which is likely to contribute to the inhibition of tumorigenesis. Collectively, these results demonstrate that CCL2 immunotherapy could be an effective therapeutic approach against inflammatory liver disease and hepatocellular carcinoma. Mol Cancer Ther; 16(2); 312-22. ©2016 AACR.