Abstract
Due to their chemoattractant properties stimulating the accumulation of infiltrating immune cells in tumors, chemokines are known to have antitumor effects. Fractalkine, a unique CX3C chemokine, is expressed in activated endothelial cells, while its receptor, CX3CR1, is expressed in cytolytic immune cells, such as natural killer cells, monocytes and some CD8(+) T cells. The biological properties of cancer cells are affected by the implantation organ and differences in immune systems, requiring cancer implantation in orthotopic organs in an in vivo experiment. To develop new therapy strategies for lung cancer, an animal model reflecting the clinical features of lung cancer was previously established. This study aimed to determine whether CX3CL1-induced biological functions should be used for immune cell-based gene therapy of lung cancer in the orthotopic implantation model. An orthotopic intrapulmonary implantation of CX3CL1-stable expression in mouse lung cancer (LLC-CX3CL1) was performed to analyze growth. Results showed a significant decrease in tumor growth in the lung compared to the control cells (LLC-mock). Furthermore, the antitumor effects of CX3CL1 were derived from natural killer cell activities in the depletion experiment in vivo. Therefore, CX3CL1 has the potential of a useful therapeutic target in lung cancer.