Objective To microencapsulate a genetically engineered cell line which stably secrete human endostatin (hES).Methods Endostatin gene fragment was amplified from plasmid pcDNA3-Endo by polymerase chain reaction, and inserted into mammalian eukaryotic expression vector pEGFPN1, resulting into recombinant plasmid pEGFP-N1-ES.Hek-293 cells were transfected with pEGFP-N1-ES via cationic liposome and selected by G418, and were measured by Western blot for endostatin protein expression.The hES/293 cells were further entrapped by alginate-chitosan-alginate (ACA) microcapsules, and the expression of endostatin in the supernatant of cultured hES/293 cell microcapsules was examined by western blot at different time points.Results Recombinant plasmid pEGFP-N1 endostatin was digested by HindIII and BamHI, and resulted into 2 DNA fragments of 7 kb and 600 bp. The sequence of the 600 bp fragment was identical to human endostatin. Western blot of the supernatant of cultured hES/293 cells or hES/293 cell microcapsules detected a positive band with the relative molecular mass of 20times;103.Conclusion The hES protein was expressed in HeK-293 transfected with pEGFP-N1-endostatin, and secreted to the culture medium,and can freely diffused outside the micro-capsule.
