Objective To observe biological characteristics of microencapsulated human endostatin/293 (hES/293) cells at different density and their inhibitory effects on the proliferation of human umbilical vein endothelial cells (HUVEC). Methods The microencapsulated hES/293 cells at different cellular density of 1×104 (group A), 1×106 (group B) and 1×108 (group C) cells/ml were made by polyelectrolyte complexometry technology. The empty microcapsules were set as control group (group D). Each group has 6 samples. After 1, 3, 7, 14 and 35 days in culture, the number of total cells, viable cells was counted by trypan blue staining, and the survival fraction was measured. The grow status of hES/293 cells was measured by MTT assay, and the concentration of endostatin protein in supernatant was measured by enzyme linked immunosorbent assay (ELISA). HUVECs were cocultured with hES/293 cells of group A, B and C. The proliferation of HUVEC at the 24, 72 and 120 hours after coculture was measured by MTT assay. Results The number of total cells and viable cells were increasing and the survival fraction reached its peak after 3 days in culture in group A, B and C. The growth rate in group A was higher than that in group B and C after 3 days in culture (P＜0.05), but the growth rate in group B was higher than that in group A and C after 7, 14 and 35 days in culture (P＜0.05). The concentration of endostatin protein in the supernatant was the same in group A, B and C after 1 and 14 days in culture (P＞0.05). However, group A had higher endostatin than group B and C after 3 days in culture, group B had higher endostatin higher than group A and C after 7 and 35 days in culture (P＜0.05). The hES/293 cells of group A, B and C had no effects on the proliferation of HUVEC(P＞0.05) after 24 hours coculture, but can inhibit the proliferation of HUVEC after 72 or 120 hours co-culture (P＜0.05). Conclusions The microencapsulated hES/293 cells at a density of 1×106 cells/ml can grow and survive, and release endostatin protein stably. The microencapsulated hES/293 cells at different density all can inhibit the proliferation of HUVEC.
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.