Objective: A new angiogenesis inhibitor HIAF-1 (human inhibitor angiogenesis factor-1) was cloned, expressed in E. coli and its antitumor activity was studied.
Methods: HIAF-1 was amplified by RT-PCR from human fetal liver tissue, then cloned into pET30a(+) vector and expressed in E. coli BL21:DE3 after sequencing. In vitro endothelial proliferation inhibiting activity of HIAF-1 was examined by MTT method. In vivo antitumor activity was studied in a murine model of IVTA2MA-891.
Results: HIAF-1 was first cloned from human fetal liver tissue. Sequence analysis of the inhibitor revealed identity to a c-terminal fragment of human collagen XVIII. HIAF-1 was effectively expressed in E. coli with a yield of 88 mg/L. Recombinant HIAF-1 protein could inhibit endothelial cell proliferation in vitro with an IC50 value of 7.5 micrograms/ml. In vivo studies showed that HIAF-1 inhibited growth rate of the primary tumor by 46.6% and metastasis by 68.9%.
Conclusion: The cloned and the bio-engineering product of HIAF-1 is an angiogenesis inhibitor, capable of inhibiting tumor growth and metastasis.