Overexpression of Hepatocyte Chemerin-156 Lowers Tumor Burden in a Murine Model of Diethylnitrosamine-Induced Hepatocellular Carcinoma

Abstract

The tumor inhibitory potential of the highly active chemerin-156 isoform was described in orthotopic models of hepatocellular carcinoma (HCC). The majority of HCC arises in the fibrotic liver, which was not reproduced in these studies. Here, a potential therapeutic activity of chemerin-156 was evaluated in diethylnitrosamine (DEN)-induced liver cancer, which mimics fibrosis-associated HCC. Mice were infected with adeno-associated virus (AAV) six months after DEN injection to overexpress chemerin-156 in the liver, and animals injected with non-recombinant-AAV served as controls. Three months later, the animals were killed. Both groups were comparable with regard to liver steatosis and fibrosis. Of note, the number of very small tumors was reduced by chemerin-156. Anyhow, the expression of inflammatory and profibrotic genes was similar in larger tumors of control and chemerin-156-AAV-infected animals. Although genes with a role in lipid metabolism, like 3-hydroxy-3-methylglutaryl-coenzym-A--reductase, were overexpressed in tumors of animals with high chemerin-156, total hepatic cholesterol, diacylglycerol and triglyceride levels, and distribution of individual lipid species were normal. Chemerin-156-AAV-infected mice had elevated hepatic and systemic chemerin. Ex vivo activation of the chemerin receptor chemokine-like receptor 1 increased in parallel with serum chemerin, illustrating the biological activity of the recombinant protein. In the tumors, chemerin-155 was the most abundant variant. Chemerin-156 was not detected in tumors of the controls and was hardly found in chemerin-156-AAV infected animals. In conclusion, the present study showed that chemerin-156 overexpression caused a decline in the number of small lesions but did not prevent the growth of pre-existing neoplasms.

Chemerin Isoform-Specific Effects on Hepatocyte Migration and Immune Cell Inflammation

“…IL-8 and osteopontin were not regulated by huChem-157 in PBMC. The protective activity of muChem-156 in HCC, which resembles huChem157 [ 1 , 6 , 8 , 9 ], appears not to impact these molecules. Moreover, central pathways in cell proliferation and migration [ 5 , 6 , 8 ] were not activated in hepatocytes with chemerin isoform overexpression.…”

“…Chemerin was precipitated from the cell culture medium by the Pierce TM Classic Magnetic IP/CoIP kit (Thermo Fisher Scientific, Waltham, MA, USA) and the chemerin antibody AF2324 for human and AF2325 for the murine protein (R&D Systems). Mass spectrometry of chemerin protein was described recently in detail [ 9 ].…”

“…MuChem-156-overexpressing Hepa1-6 cells had reduced nuclear factor-κB activation and granulocyte-macrophage colony-stimulating factor (GM-CSF) production [ 8 ]. In a murine diethylnitrosamine (DEN)-induced liver cancer model, muChem-156 overexpression reduced the number of early liver lesions [ 9 ]. However, larger tumors did not differ among the control and muChem-156 group [ 9 ].…”

“…In a murine diethylnitrosamine (DEN)-induced liver cancer model, muChem-156 overexpression reduced the number of early liver lesions [ 9 ]. However, larger tumors did not differ among the control and muChem-156 group [ 9 ]. Moreover, muChem-155 was the prominent active chemerin isoform in mouse liver tumors [ 9 ].…”

“…However, larger tumors did not differ among the control and muChem-156 group [ 9 ]. Moreover, muChem-155 was the prominent active chemerin isoform in mouse liver tumors [ 9 ]. MuChem-156 and muChem-155 had a comparable activity in Ca 2+ mobilization and chemotaxis assays [ 12 ].…”