Ulinastatin Inhibits Breast Cancer Liver Metastases Of Mice Through CCL17/CCL22-CCR4 Pathway

Background and purpose: More and more evidences have shown the key roles of chemokines in the formation and metastasis of cancers.In this study.We investigated the molecular mechanisms of liver metastasis of breast cancer and the effects of Ulinastatin on liver metastasis of mammary cancer mediated by CCL17/CCL22–CCR4 pathway.Methods: A mouse xenograft model and corresponding control were established by subcutaneously inoculating 4T1 breast cancer cells into mouse mammary glands.Fifteen days later,the mice were sacrificed,and the breast tumors were weighed.Immunohistochemistry was performed to detect CCR4 protein expression in breast tumors and CCL22 and CCL17 protein expressions in liver metastases.The CCR4 gene was found to be inhibited by lentiviral transduction in 4T1 breast cancer cells.Western blot was used to examine the inhibitory effect.The same method was used to induce breast tumorigenesis and examine tumor growth.Three different concentrations of ulinastatin were used to treat 4T1 tumor-bearing mice.Fifteen days later,immunohistochemistry was used to assess the expressionof CCL4 in breast tumors and the expression of CCL22 and CCL17 in liver tissue.Western blot and RTFQ-PCR were used to detect the expressions of TGF-?,microRNA-34 a and microRNA-31.We also analyzed the correlation between TGF-? and microRNA-34 a,microRNA-31,CCL22,and CCL17.Results: The results showed that CCR4 was highly expressed in mouse breast tumors.CCL22 and CCL17 were highly expressed in the liver metastases.CCR4 expression was silenced in the 4T1 breast cancer cells and the in vivo growth of breast cancer xenograft model was inhibited.Ulinastatin significantly inhibited CCR4,TGF-?,CCL22,micro RNA-31,and CCL17,but upregulated microRNA-34 a.Conclusion: These results showed that ulinastatin can inhibit breast cancer liver metastasis.The specific mechanism may involve ulinastatin acting on TGF-?-microRNA-34a-CCL22 and microRNA-31-TGF-?-CCL17 axes to inhibit CCL17/CCL22-CCR4 signaling pathways in live tissues.