Blockade of chemokine receptor CXCR4 for the treatment of hepatocellular carcinoma metastasis

Abstract

Background Hepatocellular carcinoma (HCC) is one of the five most common cancers worldwide. The prognosis of HCC is poor and the metastatic rate is high in HCC patients. However, the mechanism of HCC metastasis remains largely unclear. Here we investigated the potential role of SDF-1 and its receptor, Chemokine (C-X-C motif) receptor 4 (CXCR4), in HCC metastasis and explored the therapeutic potential of CXCR4 blockade for the treatment of HCC metastasis. Methods and Results This study included three parts. In vitro, higher levels of CXCR4 expression were detected in metastatic HCC cell lines (MHCC 97H and MHCC 97L) than non-metastatic cell line (PLC) by western blot, flow cytometry, and immuno-fluorescent staining. Interestingly, metastatic cell lines secreted lower levels of SDF-1 into the culture medium than non-metastatic cells. SDF-1 up-regulated adhesion molecule ICAM-1, induced filapodia formation and stimulated the chemotaxis of MHCC97L and MHCC97H cells. Blockade of CXCR4 activity by CXCR4 antagonist, CTCE-9908 (Chemokine Therapeutics Corp.) inhibited SDF-1 mediated migration of MHCC97L and MHCC97H cells at 5 µM. On the other hand, CTCE-9908 suppressed proliferation of tumor cells and induced cell apoptosis with doses higher than 100 μM. In contrast, CTCE-9908 did not arrest cell cycle progression even at the highest doses. In vivo, an orthotopic HCC model was induced by injection of MHCC97L cells into the left lobe of the liver of nude mice and the tumor-bearing mice were treated with CTCE-9908 for 6 weeks. Administration of CTCE-9908 subcutaneously significantly decreased the number of circulating tumour cells and decreased the number of metastatic tumor nodules in the lung. A mild inhibitory effect on tumor growth was also observed with CTCE-9908 treatment. The expression of CXCR4 in human HCC tumor and non-tumorous tissues was investigated by immunohistochemisty. CXCR4 was highly expressed in tumour tissues with different staining patterns. Diffused nuclear and cytoplasmic staining was identified in the non-metastatic tumor tissues, while strong nuclear staining only was detected in the tumor tissues with secondary lung metastasis. ConclusionSDF-1/CXCR4 axis plays an important role in the migration and metastasis of HCC. Blockade of SDF-1/CXCR4 interaction is a potential therapeutic strategy for the treatment of HCC metastasis.