ABSTRACT
Background: Gain-of-function of fibroblast growth factor receptor 3 (FGFR3) is involved in the pathogenesis of many tumors. More and more studies have focused on the potential usage of therapeutic single-chain Fv (ScFv) antibodies against FGFR3. RNA interference (RNAi) has been considered as a promising therapeutic method against cancer. A tool which can deliver small interference RNAs (siRNAs) into FGFR3 positive cancer cells is very promising for anti-tumor therapy. Results: In this study, a novel fusion protein R3P, which consists of FGFR3-ScFv and protamine, was generated in Escherichia coli by inclusion body expression strategy and Ni-NTA chromatography. Its yield reached 10 mg per liter of bacterial culture and its purity was shown to be higher than 95%. 1 µg of R3P could efficiently bind to about 2.5 pmol siRNAs and deliver siRNAs into FGFR3 positive RT112 and K562 cells. Annexin V staining results showed that R3P can deliver the amplified breast cancer 1 (AIB1) siRNAs to induce RT112 cell apoptosis. Conclusion: These results indicated that R3P was a promising carrier tool to deliver siRNAs into FGFR3 positive cancer cells and to exert anti-tumor effect.
Subject(s)
Urinary Bladder Neoplasms/metabolism , Recombinant Fusion Proteins/metabolism , Single-Chain Antibodies/metabolism , Recombinant Fusion Proteins/genetics , Protamines/metabolism , Inclusion Bodies , Cloning, Molecular , Apoptosis , RNA, Small Interfering , Escherichia coli/metabolism , Receptor, Fibroblast Growth Factor, Type 3 , Single-Chain Antibodies/isolation & purification , Single-Chain Antibodies/genetics , Flow CytometryABSTRACT
Background Overexpression or mutated activation of Fibroblast growth factor receptor 3 (FGFR3) is involved in the pathogenesis of many tumors. More and more studies focus on the potential usage of therapeutic antibodies against FGFR3. Results In this study, a novel single-chain Fv (ScFv) against FGFR3 was prepared and characterized. To achieve the soluble expression, ScFv was fused with Sumo (Small ubiquitin-related modifier) by polymerase chain reaction (PCR), and cloned into pET-20b. The recombinant bacteria were induced by 0.5 mM Isopropyl-ß-d-thiogalactopyranoside (IPTG) for 16 h at 20°C, and the supernatant liquid of Sumo-ScFv was harvested and purified by Ni-NTA chromatography. After being cleaved by the Sumo protease, the recombinant ScFv was released from the fusion protein, and further purified by Ni-NTA chromatography. The purity of ScFv was shown to be higher than 95% and their yield reached 4 mg per liter of bacterial culture. In vitro data showed that ScFv can significantly attenuate FGF9-induced phosphorylation of FGFR3. Conclusion We provide a novel method to produce soluble expression and bioactive functions of ScFv in Escherichia coli.