Soluble recombinant endostatin purified from Escherichia coli: antiangiogenic activity and antitumor effect.

Endostatin is a potent and specific antiangiogenic protein capable of inhibiting the growth of murine and xenotransplanted human tumors. Thus far, however, recombinant endostatin prepared from Escherichia coli is insoluble after purification and therefore inappropriate for clinical settings. A soluble form of endostatin is available from a yeast system with relatively low yield and high cost, which has made it difficult to produce endostatin in quantities sufficient for extensive clinical evaluation. In this study, we developed a protocol to generate soluble recombinant murine endostatin from E. coli at a yield of 150 mg/liter-culture and 99% purity. The in vivo antiangiogenic and antitumor activities of the soluble recombinant endostatin are equally as potent as those of the previously published insoluble form. A similar protocol may be used to produce soluble human endostatin.