High-yield expression, purification and characterization of tumor-targeted IFN-α2a

BackgroundIFN-α has been shown to be effective against hematologic malignancies. However, it is ineffective against most solid tumors and has not been satisfactory because of its toxicity.MethodsThe NGR (Asn-Gly-Arg) peptide is a tumor-homing peptide. In order to increase the anti-tumor activity of IFN-α2a and lower the dose, we coupled a cyclic NGR peptide with the C terminus of IFN-α2a (named IFN-α2a–NGR).ResultsThe fusion protein was expressed in E. coli and purified by ion-exchange chromatography. The purity of IFN-α2a–NGR was >98% and the final purification yield of IFN-α2a–NGR was approximately 18 mg/L. The anti-tumor efficacy and the binding ability of IFN-α2a–NGR with tumor vasculature were investigated in vitro and in vivo.DiscussionOur study has demonstrated that the anti-tumor efficacy of IFN-α2a–NGR is significantly increased in comparison with IFN-α2a, and IFN-α2a–NGR could selectively target tumor vessels. These data indicate that the tumor-homing peptide (NGR) can enhance the therapeutic efficacy of IFN-α2a against tumors.