CXCR 4 antagonist inhibits stromal cell-derived factor 1-induced migration and invasion of human pancreatic cancer

The stromal cell-derived factor-1 (SDF-1)/CXCR4 system is implicated in various instances of cell migration in mammals, including the migration of lymphocytes and the formation of metastases. We have recently synthesized a potent novel CXCR4 antagonist, TN14003. The purpose of this study was to investigate the role of SDF-1/CXCR4 axis in the pancreatic cancer metastasis via cell migration and invasion, and the inhibitory effect of TN14003 on pancreatic cancer cell metastasis. The expression of CXCR4 was detected in six pancreatic cancer cell lines by Western blotting and immunocytochemistry. In migration and invasion assays, SDF-1 stimulated both migration and invasion of cancer cells in a dose-dependent manner. The maximal effect of SDF-1 was observed at 100 ng/ml. SDF-1-induced migration and invasion of cancer cells were completely blocked by 100 nM TN14003. The stimulatory effect of SDF-1 on cancer migration and the inhibitory effect of TN14003 were mediated via the alteration in phosphorylation of mitogen-activated protein kinases. Treatment of cancer cells with 100 ng/ml SDF-1 resulted in a significant increase of actin polymerization, which was reduced by 100 nM TN14003. SDF-1 enhanced cancer cell adhesion to laminin, which was not reversed by TN14003. Taken together, SDF-1/CXCR4 axis is involved in pancreatic cancer metastasis through migration and invasion. The small molecule antagonists against CXCR4 such as TN14003 might be an effective anti-metastatic agent for pancreatic cancer. [Mol Cancer Ther. 2004;3(1):29–37] Introduction The chemokines are a family of low molecular weight cytokines that mediate the chemical effect on target cells through seven-transmembrane G-protein-coupled receptors (1–4). Stromal cell-derived factor-1 (SDF-1), which was initially cloned by Tashiro et al. (5), is a member of the CXC subfamily of chemokines and interacts with the seventransmembrane G-protein-coupled receptor CXCR4, an exclusive receptor for SDF-1 (6, 7). Later, SDF-1 was identified as a growth factor for B-cell progenitors and also a chemotactic factor for T cells and monocytes relevant to B-cell lymphopoiesis and bone marrow myelopoiesis (6, 8, 9). Furthermore, SDF-1 was found to play a critical role in directed cell migration (6, 10) and embryonic development (8, 11, 12). Most importantly, the function of a subset of chemokine receptors as co-receptors for the entry of HIV-1 was clarified. CXCR4 and a CC-chemokine receptor, CCR5, represent major co-receptors for the entry of T-cell line-tropic HIV-1 (X4-HIV-1) and macrophagetropic HIV-1 (R5-HIV-1), respectively (13, 14). Recently, several studies have been conducted to detect the expression of CXCR4 and SDF-1 in solid tumors. The results are not uniform, and the relevance to cancer progression and tumor angiogenesis is unclear (15–17). In breast cancer, the SDF-1/CXCR4 system has been implicated in the formation of metastasis (18). Before this, we found that SDF-1 mRNA expression is detected in pancreatic cancer tissues, but is not detected in pancreatic cancer cell lines, whereas CXCR4 mRNA expression is detected in both pancreatic cancer tissues and cancer cell lines (19). To date, however, the role of interaction between SDF-1 and CXCR4 in pancreatic cancer progression has not been defined. The specific ligands for these receptors are able to inhibit HIV infection (20–23). As for the malignant solid tumors, neutralizing the interactions of SDF-1/CXCR4 by administration of an antibody to CXCR4 significantly impairs metastasis of breast cancer cells to regional lymph node and lung in the animal model. For this reason, efforts have focused on developing a specific antagonist for chemokine