ABSTRACT
This study is to investigate whether naked plasmid DNA can effectively transfect lung cancer related cells and express human kallistatin, an endogenous protein that inhibits angiogenesis and tumor growth, and to explore the biological activity of the low-level expressed kallistatin to lung cancer in vitro and in vivo. The plasmids were delivered with Lipofectamine 2000 to transfect various lung cancer related cells. Kal expression was determined by ELISA. The biological effects of Kal expression on proliferation, migration and apoptosis rate of the cells were examined. In subcutaneous NCI-H446 xenograft model, pKal was injected directly into tumors, the changes of CD34, Ki-67 and E-cadherin expression were detected with immunohistochemical assay, the tumor apoptosis was analyzed with TUNEL assay. Both the endothelial cell and lung cancer cells could express kallistatin after plasmid transfection. The proliferation and migration of human umbilical vein endothelial cells were inhibited, but the apoptosis rate was not affected. The proliferation rates of all the three tested lung cancer cells, such as NCI-H446, NCI-H460 and A549, were inhibited, and their apoptosis rates were enhanced, but different cells behaved differently. In subcutaneous NCI-H446 xenograft model, intratumor injection of pKal inhibited the growth of lung cancer by reducing angiogenesis and proliferation of tumor cells. In conclusion, this study demonstrated the efficacy of plasmid-mediated expression of kallistatin to lung cancer related cells, thus providing a basis for their clinical application in the treatment of lung cancer.