Z Gastroenterol 2015; 53 - A2_9
DOI: 10.1055/s-0035-1567981

Functional role of CCL5/RANTES for HCC progression during chronic liver disease: from humans to mice

A Mohs 1, N Kuttkat 1, J Reißing 1, HW Zimmermann 1, A Proudfoot 2, SA Youssef 3, A de Bruin 3, FJ Cubero 1, C Trautwein 1
  • 1University Hospital RWTH Aachen, Department of Internal Medicine III, Aachen, Germany
  • 2Merck Serono Geneva Research Centre, Geneva, Switzerland
  • 3Utrecht University, Dutch Molecular Pathology Center, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht, The Netherlands
  • 4University of Groningen, University Medical Center Groningen, Department of Pediatrics, Groningen, The Netherlands

Background & Aims:

Hepatocellular carcinoma (HCC) which is the consequence of malignant transformation of hepatocytes, is often based on chronic inflammation, resulting in liver fibrogenesis. During this process chemokines play a crucial role by attracting immune cells. In the current study, the function of CCL5/RANTES during chronic liver disease (CLD) was analysed in patients and two independent murine models of inflammation triggered HCC development. We showed that CCL5 acts mainly through immune cells by influencing the pro-inflammatory milieu in the diseased liver. Finally, we present an efficient therapeutic option for CLD in mice with implications for humans.

Methods:

The expression of CCL5 and its receptors was studied in well-defined CLD patients and in the two murine inflammation based HCC models NEMOΔhepa and Mdr2-/-. The role of CCL5 in inflammation, fibrosis, tumour initiation and progression was analysed in different cell populations using NEMOΔhepa/CCL5-/- mice and subsequent bone marrow transplantation (BMT) studies. For therapeutic intervention Evasin-4 was injected either for 24 hours or for 8 weeks.

Results:

In CLD patients, CCL5 expression correlated with inflammation stage and fibrosis grade in CLD patients. Interestingly, despite CCR1 and CCR3, CCR5 was upregulated in this cohort. This expression pattern was further confirmed in NEMOΔhepa mice during hepatocarcinogenesis. In contrast, in the second model of Mdr2-/- mice, only CCL5 was significantly upregulated, indicating a predominate role of this chemokine. Genetic inactivation of CCL5 in NEMOΔhepa mice diminished hepatocyte apoptosis, compensatory proliferation and fibrogenesis due to reduced immune cell infiltration. In this context, especially CD45+ Ly6G+ granulocytes, CD45+ CD11b+ Gr1.1+ F4/80+ pro-inflammatory monocytes, and T-CD4+ - and CD8+ cells were decreased in NEMOΔhepa/CCL5-/- livers. As a consequence late stage NEMOΔhepa/CCL5-/-, mice displayed smaller and less malignant tumours, characterized by significantly reduced proliferative capacity and less pronounced angiogenesis in comparison with NEMOΔhepa tumors. Mechanistically, we identified hematopoietic cells as main source of CCL5, while CCL5 deficiency did not sensitise NEMOΔhepa hepatocytes towards TNF induced apoptosis. In a short term intervention experiment we demonstrate that especially CD45+ Ly6G+ granulocytes were reduced after Evasin-4 treatment. Subsequently, NEMOΔhepa mice were treated with Evasin-4 for 8 weeks. Pharmacologic intervention of the CCL5 pathway histologically resulted in a significant improvement of liver fibrosis confirmed by reduction of established fibrosis markers (αSMA, Collagen IA1, TGF-β, MMP-2 und MMP-3).

Conclusion:

Our present study identifies the essential role of CCL5 for disease progression and especially HCC development in men and in mice. Finally, inhibition of CCL5 in vivo appears to be encouraging for therapy of human CLD.

Corresponding author: Mohs, Antje

E-Mail: amohs@ukaachen.de