ADENOVIRUS-MEDIATED EXPRESSION OF PEX, A NONCATALYTIC FRAGMENT OF MATRIX METALLOPROTEINASE-2, AND IT’S INHIBITION ON ANGIOGENESIS AND TUMOR GROWTH

Objective: To develop an adenovirus system to deliver biologically active peptides or proteins such as angiogenesis inhibitors in vivo for the treatment of cancer. Methods: DNA recombination techniques were employed to construct adenovirus shuttle vector, in which angiogenesis inhibitor was put downstream of rat growth hormone signal peptide, and the C-terminal was the myc-epitope 10-amino-acid peptide for the following up of the protein. Adenovirus was made using the bacteria recombination method. We tested this system using an angiogenesis inhibitor chick MMP-2 C-terminal hemopexin-like fragment (PEX) in Sarcoma 180 (S-180) bearing Kunming mice. The anti-angiogenic effect was performed by chick chorioallantoic membrane assay. Results: PEX was readily secreted outside human stomach carcinoma BGC823 cells as demonstrated by immunofluorescent staining and western blot infected by adenovirus with rat growth hormone signal peptide (E-T-rGH-PEX). However, without signal peptide (E-T-PEX), PEX was expressed and localized in the cytoplasm of the infected cells, and formed large aggregates, which suggested that PEX was insoluble. The adenovirus E-T-rGH-PEX could inhibit angiogenesis, while E-T-rGH-PEX not. The adenoviruses of E-T-rGH-PEX inhibited the growth of S-180 tumor significantly compared with the empty virus control group E-T (P=0.026) and without signal peptide group E-T-PEX (P=0.006) respectively, while E-T-PEX had little effect. Conclusion: These results suggest that this adenoviral system is likely to be used in the gene therapy of cancer to deliver angiogenesis inhibitors.