In Vitro Evaluation of Vegf-Pseudomonas Exotoxin: A Conjugated on Tumor Cells

Document Type : Original Article


1 Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran

2 Department of Parasitology, Pasteur Institute of Iran, Tehran, Iran

3 Department of Genetics and Molecular Biology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan; Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Noncommunicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran

4 Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran

5 Department of Pilot Nanobiotechnology, Pasteur Institute of Iran, Tehran, Iran


Background: Angiogenesis which occurs mandatory in solid tumors, is a critical step in malignancy progression. Vascular endothelial growth factor (VEGF) is mainly responsible for angiogenesis process and facilitates the formation of new vessels. Distribution of monoclonal antibodies against VEGF or VEGF receptor (VEGFR) into the solid tumors is limited because of their huge dimensions. Moreover, many investigations have demonstrated the usefulness of immunotoxins to halt angiogenesis in solid tumors. Materials and Methods: We designed, expressed and evaluated the cytotoxicity of a novel nano-immunotoxin composed of VEGF splice variant containing 121 amino acids (VEGF121) and truncated the exotoxin A of Pseudomonas aeruginosa (PE38-KDEL). The fusion protein VEGF121-PE38 was successfully cloned and expressed in Escherichia coli, purified by Ni+ 2 affinity chromatography. The fusion protein was subsequently subjected to refolding using the reduced and oxidized glutathione. Results: The expression level of the fusion protein reached to 1 mg/ml. The VEGF121-PE38 immunotoxin showed a 59 KDa MW which had cytotoxic effect on HUVEC and 293/KDR cells as low and high expressing VEGFR2 cells, respectively. But the cytotoxicity on 293/KDR was 100 folds more than that of VEGFR2 low expressing cell HUVEC. Conclusion: The designed immunotoxin showed more selectivity for higher VEGFR2 expressing cells in vitro.


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