Intra-tumoral administration of naked plasmid DNA encoding mouse endostatin inhibits renal carcinoma growth

Endostatin is a C-terminal fragment of collagen XVIII and has potent anti-a ngiogenic and anti-tumor activity. Mouse endostatin-coding sequences were o btained using PCR and linked to the signal sequence of influenzavirus hemag glutinin. The signal-sequence endostatin fragment was subcloned into plasmi d vectors under the transcriptional control of cytomegalovirus promoter. Mu rine renal carcinoma (Renca) cells transfected with endostatin-coding plasm id are shown to secrete full-length endostatin. Endostatin-secreting Renca cells demonstrate slower growth in vivo compared to empty vector-transfecte d cells, but their in vitro growth is unaffected. Anti-angiogenic activity of secreted endostatin was confirmed in a Matrigel angiogenesis assay in vi vo. We report growth inhibition of Renca tumors resulting from intra-tumora l delivery of plasmid vector encoding secretable endostatin, Elevated local concentrations of endostatin resulted from multiple intra-tumoral injectio ns of endotoxin-purified plasmid DNA. Local endostatin levels were high eno ugh to obtain growth arrest of Renca tumors. (C) 2001 Wiley-Liss, Inc.