Expression, purification and biological effect of a novel single chain Fv antibody and protamine fusion protein for the targeted delivery of siRNAs to FGFR3 positive cancer cells

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.

Expression and purification of soluble single-chain Fv against human fibroblast growth factor receptor 3 fused with Sumo tag in Escherichia coli

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.

Preparation and Identification of Anti-lactoferrin Single Chain Fv Antibody / 医学研究杂志

Objective To prepare a specific anti-lactoferrin single chain variable fragment(ScFv).Methods Anti-lactoferrin clones were screened from a 'naive' phage antibody library against the immobilized lactoferrin antigen,then the clones were transformed to the E.coli HB2151 to give soluble expression of antibody fragments.The culture supernatant containing ScFv was purified by immobilized metal affinity chromatography,and then determined with SDS-PAGE and ELISA.Results The results demonstrated that ScFvs were specific;they did not react with transferrin,lysozyme and bovine serum albumin in ELISA.The SDS-PAGE showed that the ScFvs had high purity through affinity chromatography and the molecular weight of them was about 32 kD.Conclusions The successful generation of the ScFvs against lactoferrin provides a basis for further study and clinical applications for dry eye and other ocular diseases.

Nanocomoposite probes composed of fluorescent magnetic nanoparticles and PSA ScFv antibody for targeted imaging and therapy of prostate cancer / 中国肿瘤生物治疗杂志

Objective:To investigate the feasibility of targeted imaging and therapy of prostate cancer using nanocomposite probes composed of fluorescent magnetic nanoparticles(FMCNPs) and single chain Fv(ScFv) antibody specific for gama-seminoprotein.Methods:The nanocomposite probes(FMCNPs-ScFv) were prepared by conjugating fluorescent magnetic nanoparticles with singlegama-chain Fv antibody specific gama-seminoprotein,and were characterized by high resolution transmission electron microscopy,fluorescent spectrum and magnetic spectrum.Nanocomposite probes were incubated with prostate cancer LNCaP cells,and the targeting results of nanocomposite probes were observed by fluorescent microscopy.The cytotoxicity effect of the nanocomposite probes was measured by MTT.Nude mice models of prostate cancer were established and identified by immunohistochemistry method.The nanocomposite probes were injected into nude mice via tail vein.The distribution of nanocomposite probes in the nude mice was observed by Micro-animal imaging system,targeted imaging of the prostate cancer was observed by MR instrument.The nude mice with prostate cancer were irradiated with 100 W magnetic field for 30 min,and the changes of tumor sizes were observed.Results:The FMCNPs-ScFv nanocomposite probes were successfully prepared.Nanocomposite probes entered into the cytoplasm of cancer cells and exhibited low cytotoxicity effect.Nude mice model with prostate cancer were successfully fabricated;the nanocomposite probes distributed quickly in the main organs of mice,and gradually concentrated on the tumor tissues within 24 h.MR images showed that the tumor images were gradually enhanced from 6 h to 24 h after injection of the nanocomposite probe.Four days after magnetic irradiation,the tumors in the nude mice grew slower compared with the control nude mice(P

Screening and identification of anti-HRPII single chain Fv antibodies of Plasmodium falciparum / 细胞与分子免疫学杂志

To develop simple, rapid, and efficacious diagnostic methods for malaria is one of the remaining key tasks for malaria control. Previously, we have created a phage-displayed antibody library against Plasmodium falciparum. Six clones of antibody with good reactivity to HRP-II in ELISA were isolated from the library after 3 rounds of enrichment. Soluble ScFvs were produced and the characteristics were determined. The results of Western blot showed that they could bind to HRP-II specifically and had a relative molecular mass(Mr) about 31 000. The work provided a solid fund for diagnostic kit development for malaria.

Preparation and immunohistochemical study of human single chain Fv antibody against hepatitis C virus core antigen / 解放军医学杂志

Objective To detect hepatitis C virus core antigen in 7721 cells transfected with HCV cDNA by immunohistochemistry method with human single chain Fv antibody(scFv). Methods The recombinant phages were panned by core antigen which was coated in a microtiter plate. After three rounds of biopanning, 48 clones were identified specific to core antigen. The affinity and specificity of scFv were evaluated by ELISA and immunohistochemistry. Results ScFv-core DNA digestion and sequence data showed that the scFv gene was composed of 774bp. Conclusion Human single chain Fv antibody against HCV core antigen has a specific combining capacity with hepatitis C virus core antigen.

EXPRESSION OF SOLUBLE HUMAN ScFv AGAINST CORE PROTEIN OF HEPATITIS C VIRUS IN E COLI / 解放军医学杂志

To construct expressive vector for human ScFv against core protein of hepatitis C virus (HCV core ScFv),and to express soluble HCV core ScFv in E.coli JM109. Using phage display technique, the recombinant phages were panned by recombinant core antigen which was coated in a microtiter plate, and after five rounds of biopanning, 86 clones were identified specific to core antigen. 750 bp fragment could be released from the plasmid of positive phage clones, and the sequence analysis indicated that we have obrained the ScFv DNA fragment. Then DNA fragment was inserted into the expressive vector pCANTAB5E, and E. coli host JM109 was transformed and induced by IPTG. The specificity of ScFv in the culture medium was evaluated by enzyme linked immunosorbent assay (ELISA).The molecular weight of expressed HCV core ScFv protein is 28 000 dalton as determined with the aid of SDS polyacrymide gel electrophoresis (PAGE). The expressed HCV core ScFv protein will be useful in the immunohistochemical study of liver tissue from patients with hepatitis C and gene therapy against HCV infection.

HIGH LEVEL EXPRESSION AND ACTIVITY DETECTION OF SINGLE CHAIN IMMUNOTOXIN 183B_2ScFvPE38 AGAINST OVARIAN CARCINOMA / 解剖学报

Objective To prepare the immunotoxin protein (183B 2ScFvPE38) which might be useful in immuno guided therapy for ovarian carcinoma and study the activity of the protein. Methods The methods of ELISA and cytotoxicity were used to study the immunotoxin after induced with IPTG and the activity of the immunotoxin. Results The expressed fusion proteins were detected mostly as inclusion bodies at high level, and soluble immunotoxins were also observed. The results showed liable activity of antibody part and toxic part. Conclusion The recombinant fusion protein 183B 2ScFvPE38 keeps the activity of both components and might be of great use in the future to deal with ovarian carcinoma. [