Investigation of Antiangiogenic Tumor Therapy Potential of Microencapsulated HEK293 VEGF(165)b Producing Cells

To investigate the antiangiogenic potential of encapsulated VEGF(165)b producing HEK293 cells, Human Embryonic Kidney 293 (HEK293) cells were stably transfected to produce VEGF(165)b. Then they were encapsulated in alginate - polylysine -alginate (APA) microcapsules. VEGF(165)b productivity and viability of encapsulated cells were analyzed and compared with the non-encapsulated cells. Results showed that encapsulated cells proliferated and remained viable within the microcapsules throughout the 28-day period of the experiment. The quantity of VEGF(165)b increased from 6.5 +/- 1.2 mu g/ml at day 13 to 13 +/- 0.96 mu g/ml at day 16. Then it gradually dropped to 5 + 1.2 mu g/ml for the last 3 days period as measured at day 28. Production of VEGF(165)b from encapsulated and non-encapsulated cells was similar. The effect of VEGF(165)b harvested from encapsulated cells on Human Umbilical Vein Endothelial cells (HUVECs) proliferation were also examined. The same inhibitory effects on HUVECs proliferation was seen when the cells were incubated with a mixture of VEGF(165)b and a 2-fold VEGF(165)b or with VEGF(165)b and 2-fold excess VEGF(165)b released from encapsulated cells. Subcutaneous injection of microencapsulated VEGF(165)b producing cells in tumor site of nude mice resulted in the reduction of the number of vessels around the tumors.