VEGF165b mutant with a prolonged half-life and enhanced anti-tumor potency in a mouse model

VEGF165b has been shown to be an effective anti-cancer agent; however, its short half-life limits further application in the clinical field. The development of a mutant VEGF165b with a prolonged half-life is urgently needed for its future application. A mutant VEGF165b was generated by inactivation of its plasmin cleavage site. The mutant and native VEGF165b proteins without purification tags were expressed via the Pichia pastoris expression system followed by purification with a HiTrap heparin affinity chromatography column through optimization of the purification conditions. Furthermore, its binding affinity with VEGF Receptors and its functions in vitro and in vivo were examined. Results showed that the half-life of mutant VEGF165b increased to approximately 10 times (Intravenous), 9.1 times (Intraperitoneal) and 5.4 times (Subcutaneous) greater than that of VEGF165b, and the mutation did not cause significant alteration of VEGFR1 and VEGFR2 binding affinity. Mutant VEGF165b inhibited the proliferation and migration of HUVECs in vitro, similar to the native VEGF165b. In a mouse melanoma model, mutant VEGF165b exhibited stronger anti-tumor activity in comparison with its native counterpart. These results indicate that the mutant VEGF165b had a prolonged half-life and retained the anti-angiogenic activity of the native VEGF165b, suggesting that this novel mutant VEGF165b may be a stronger anti-cancer agent.