Effect Of CXCR1/CXCR2 Antagonist On Lymphatic Metastasis Of Ascites Hepatocarcinoma In Mouse

Objective: Chemokines, a class of low weight molecular peptides, show the effects of chemotaxis, participate in the immunoregulation and immunopathology, and play an important role in tumor growth, metastasis, angiogenesis and organ hardening. IL-8, one of the ELR+CXC chemokines, is angiogenic factors, also the tumor autocrine growth factor, closely related to tumor angiogenesis, growth, invasion and metastasis. IL-8 works by binding with the CXC chemokine receptor CXCR1/CXCR2. We have developed a broad-spectrum ELR+CXC chemokine antagonist G31P, which has high affinity to CXCR1/CXCR2 and blocks the effects of ELR+CXC chemokines on tumor growth, metastasis, angiogenesis. In this paper, we establish animal models with murine hepatocarcinoma cell line with high lymphatic metastatic potential HCA-P/L6 and discuss the effect of CXCR1/CXCR2 antagonist-G31P on metastatic potential of the tumor cells in the animal model.Method: The murine hepatocarcinoma cell line with high metastatic lymphatic potential (HCA-P/L6) was subcutaneously inoculated into the medioventral line of mice 615 and the second generation of ascites hepatocarcinoma cells were obtained, counted, diluted with saline to the right concentration. (1) The ascites mouse model:Mice were inoculated with the second generation of HCA-P/L6 cells (1×105) into the medioventral line as the first animal model, while subcutaneous injection of G31P (100μl,500μg/kg) or saline(100μl) as the treated group and control group. Observed the weight, abdominal circumference and the survival time of the mice. (2) The metastatic model of HCA-P/L6 cells:The mice were inoculated with the second generation of HCA-P/L6 cells on posterior left foot, and subcutaneously injected with G31P or saline in the treated group and control group. Observed footpad tumor appearance and the status of tumor, lymph node enlargement; recorded the health status of mice. At 21st day, dissected the mouse, picked up lymph node of different parts and measured the longest diameter, and sampled the in situ transplanted subcutaneous tumor and suspected organs for pathology, RT-PCR to detect the expression of CXCR2, KC, MIP-2.Results: (1) The ascites mouse model: There is no significant differences of the body weights and the abdominal circumferences between G31P-treated and control. Two mice of the treated group were dead in the 10th day, one of them survived for 16 days, whereas in the control, four were dead on the 11th day, none survived for 13 days. (2) The metastatic model of HCA-P/L6 cells: The animal body weights of control groups were lighter than that of G31P-treated groups with statistic difference (p<0.05). The volume of in situ transplanted tumors in the control group significantly increased as compared with the treated group, there was significant difference (p<0.05). Metastasis rate was significantly different between two groups. The pathological examination of tumor cells in lymph nodes of control group showed sheet distribution, obvious heteromorphism, and multinucleated tumor cells, instead, only a small part of the visible individually scattered tumor cells in the treated group mice. The expressions of MIP-2 mRNA of foot pad in situ tumors in the control group were significantly increased.Conclusion: CXCR1/CXCR2 antagonist-G31P can inhibit the murine hepatocarcinoma lymphatic metastasis.