Synergistic antitumor effects of in vivo production of human endostatin and tissue inhibitor of metalloproteinase-1 in mice after subcutaneous implantation of primary fibroblasts transfected by adenovirus-mediated gene delivery

Background Tissue inhibitor of metalloproteinase （TIMP）-1 is a multifunctional protein. The aim of the study was to examine the feasibility of using a combination of adenovirus-mediated gene delivery of TIMP-1 plus endostatin and cell transplantation techniques to treat tumor growth and metastasis in mouse melanoma.Methods A enzyme-linked immunosorbent assay （ELISA） was used to detect the level of TIMP-1 and endostatin in vitro and in vivo. A tumor bearing mouse model and an experimental lung metastasis model in animal experiments were used to explore the therapeutic effect of in vivo production of human TIMP-1 and endostatin after the implantation of primary fibroblasts infected with the indicated adenovirus into tumor-bearing mice and a cytochemical method was used to observe histopathological changes of the tumor. An experimental lung metastasis model was established by injecting B16BL6 cells into the tail vein of mice and adenovirus-infected primary fibroblasts were subcutaneously implanted into the mice 24 hours later. Twenty-one days after tumor cell injection, mice were sacrificed to examine the effect on nodules visible as black forms on the surface of the lungs in B16BL6 cells.Results TIMP-1 and endostatin were secreted into the supernatants of cultures of Ad-TIMP-1 and Ad-End-infected mouse primary fibroblasts. We also observed that implantation of fibroblasts infected with Ad-TIMP-1 alone, Ad-End alone, or Ad-TIMP-1 plus Ad-End resulted in detectable blood levels which may clearly inhibit the tumor growth and metastasis in a murine melanoma model.Conclusion These results suggest the high capacity of transfection for the delivery of TIMP-1 or endostatin gene constructs into primary fibroblasts, and demonstrate that the implantation of TIMP-1 and endostatin producing fibroblasts at a site in vivo where direct secretion of TIMP-1 and endostatin into the blood is possible represented a promising approach for the development of cancer therapy.