Reduced invasiveness and metastasis of Chinese hamster ovary cells transfected with human interleukin-17 gene.

Human IL-17 (hIL-17) stimulates epithelial, endothelial, fibroblastic cells and macrophages to secrete various cytokines. The present study was designed to assess the effects of the transfection of the hIL-17 gene in Chinese hamster ovary (CHO) cells. A complementary DNA (cDNA)-encoding hIL-17 was obtained by polymerase chain reaction (PCR) amplification from human CD4+ T-cell cDNA and inserted into the plasmid pRc/CMV to construct an expression vector for hIL-17. CHO cells were transduced with hIL-17 DNA-carrying cytomegalovirus (CMV)-based retroviral vectors. A clone with a high mRNA expression of hIL-17 (CHO/IL-17) was selected by Northem blotting. There was no significant difference in the in vitro growth of cells among parent CHO cells, vector-only transfected cells (CHO/neo) and CHO/IL-17 cells. A Matrigel invasion chamber assay, however, demonstrated significantly lower invasiveness by CHO/IL-17 cells than by either the parent CHO or the CHO/neo cells. There was no difference in the in vivo growth among the cells, when subcutaneously transplanted into nude mice. When injected into the tail vein, however, the number of metastatic nodules in the lungs of CHO/IL-17-injected mice was significantly smaller than that of CHO- or CHO/neo-injected mice. Furthermore, NK activity of spleen cells was significantly higher in nude mice transplanted with CHO/IL-17 cells than in mice transplanted with parent CHO or CHO/neo cells. In conclusion, the hIL-17-gene-transfected CHO cells showed a significantly lower metastatic potential to the lung by directly modulating the invasiveness and metastasis of CHO cells as well as by enhancing NK activity.