NK4 growth inhibition of human Raji lymphoma xenografts by competitive interrupting HGF/Met signal pathway / 中华病理学杂志

<p><b>OBJECTIVE</b>To observe the inhibition of NK4 protein in the proliferation of human Raji lymphoma xenografts in nude mice, and to explore its molecular mechanism.</p><p><b>METHODS</b>Models of human Raji lymphoma xenograft transfected with HGF gene were established by subcutaneous inoculation in nude mice. After establishment of the models, the mice received continuous NK4 protein via tail vein for 4 weeks, and the weight and tumor growth were monitored every week. After 8 weeks, the expression of HGF mRNA and c-Met mRNA of tumor tissues was measured by real-time fluorescent quantitation PCR. The apoptotic index (AI) and microvessel density (MVD) were evaluated by terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) and immunohistochemistry, respectively.</p><p><b>RESULTS</b>The models of human Raji lymphoma xenograft were successfully established. Although the animal weights of all groups declined, especially in the groups with NK4 protein injection, there was no statistical significance (P > 0.05). The tumor volume in HGF gene transfected group was larger than those of the control groups (P < 0.01), and there was no statistical significance among the control groups (P > 0.05). However, the tumor volume of the NK4 protein injection group decreased significantly (P < 0.01). Expression of HGF mRNA and c-Met mRNA in HGF gene transfected group increased significantly after injection of NK4 protein (P < 0.01). AI in HGF gene transfected group (33.5% ± 12.3%) was significantly lower than that of control groups (89.1% ± 22.3% vs. 81.9% ± 27.0%, P < 0.05), but became significantly higher (119.1% ± 18.9%) after NK4 protein injection (P < 0.01). MVD in HGF gene transfected group (28.5 ± 2.0) was higher than that of control groups (12.2 ± 1.4, 13.8 ± 1.3, P < 0.01), although declined (15.5 ± 2.5) after NK4 protein injection (P < 0.01).</p><p><b>CONCLUSIONS</b>NK4 protein suppresses significantly the growth of human Raji lymphoma xenografts transfected with HGF gene. The pathogenesis may be involved in promoting tumor cell apoptosis and restraining tumor angiogenesis through competitive interrupting HGF/Met signal pathway.</p>

Expression, purification and preliminary activity study of recombinant hepatocyte growth factor protein in E.coli / 中华微生物学和免疫学杂志

Objective To prepare hepatocyte growth factor(HGF) recombinant protein and confirm its activity preliminarily according to building HGF gene prokaryotic expression vector and transforming into E.coli.Methods Clone HGF inserted into the vector pET-26b(+) to construct prokaryotic expression vector pET-26b(+)-HGF and transform into E.coli Rosseta(DE3).The transformed bacteria induced by IPTG was purified through Ni-NTA resin affinity chromatography frozen-drying after renaturation.Results HGF gene recombinant prokaryotic expression vector pET-26b(+)-HGF was constructed successfully.E.coli Rosseta(DE3) which was transformed into pET-26b(+)-HGF expresses the target protein as the form of inclusion bodies,accounting for 38％ of the total bacterial proteins,and confirmed by Western blot.HGF protein which was purified by Ni-NTA resin affinity chromatography,has a purity of about 95％,and can promote proliferation,migration,and inhibition of apoptosis for human non-small cell lung cancer cell line A549 cells after interaction.Conclusion HGF gene recombinant prokaryotic expression vector pET-26b (+)-HGF was constructed and expressed in transformed E.coli Rosseta(DE3) successfully.They resumed their recombinant HGF protein structure after purification and renaturation,and had biological activity confirmed by in vitro studies.