[The synergistic effect of FGF-21 and insulin on regulating glucose metabolism and its mechanism].

Previous studies proposed that the synergistic effect of fibroblast growth factor-21 (FGF-21) and insulin may be due to the improvement of insulin sensitivity by FGF-21. However, there is no experimental evidence to support this. This study was designed to elucidate the mechanism of synergistic effect of FGF-21 and insulin in the regulation of glucose metabolism. The synergistic effect of FGF-21 and insulin on regulating glucose metabolism was demonstrated by investigating the glucose absorption rate by insulin resistance HepG2 cell model and the blood glucose chances in type 2 diabetic db/db mice after treatments with different concentrations of FGF-21 or/and insulin; The synergistic metabolism was revealed through detecting GLUT1 and GLUT4 transcription levels in the liver by real-time PCR method. The experimental results showed that FGF-21 and insulin have a synergistic effect on the regulation of glucose metabolism. The results of real-time PCR showed that the effective dose of FGF-21 could up-regulate the transcription level of GLUT1 in a dose-dependent manner, but had no effect on the transcription level of GLUT4. Insulin (4 u) alone could up-regulate the transcription level of GLUT4, yet had no effect on that of GLUT1. Ineffective dose 0.1 mg kg(-1) FGF-21 alone could not change the transcription level of GLUT1 or GLUT4. However, when the ineffective dose 0.1 mg x kg(-1) FGF-21 was used in combination with insulin (4 u) significantly increased the transcription levels of both GLUT1 and GLUT4, the transcription level of GLUT1 was similar to that treated with 5 time concentration of FGF-21 alone; the transcription level of GLUT4 is higher than that treated with insulin (4 u) alone. In summary, in the presence of FGF-21, insulin increases the sensitivity of FGF-21 through enhancing GLUT1 transcription. Vice versa, FGF-21 increases the sensitivity of insulin by stimulating GLUT4 transcription in the presence of insulin. FGF-21 and insulin exert a synergistic effect on glucose metabolism through mutual sensitization.

[The synergism and mechanism of action of rClone30-hDR5 in combination with TRAIL on HCC].

To investigate the cell-killing effect and its possible mechanism of rClone30-hDR5 in combination with TRAIL on human hepatic carcinoma (HCC) cell line, first of all, recombinant plasmid pee12.4-hDR5 was introduced into HepG2 cells by liposome transfection. After five rounds of screening by flow cytometry, HepG2 cells expressing high levels of DR5 on cell surface were isolated. The cytotoxicity of TRAIL to selected cells was higher than that of TRAIL to HepG2 cells by MTT method (P < 0.01). The result suggested that the cloned hDR5 gene had biological activity. MTT assay showed that, rClone30- hDR5 in combination with TRAIL more efficiently inhibited the tumor growth of HepG2 cells compared to rClone30-hDR5 or TRAIL in vitro. The results of Annexin V-FITC/PI staining and Quantitative Real-time PCR indicated that rClone30-hDR5 in combination with TRAIL significantly increased the mRNA levels of caspase 3 and caspase 8, and induced the apoptosis of tumor cells. HepG2 cells were infected with rClone30-hDR5 or rClone30 at MOI of 1. The expression of hDR5 on tumor surface increased significantly by rClone30-hDR5 compared to that by rClone30, which contributed to the sensitivity to TRAIL. In conclusion, rClone30-hDR5 in combination with TRAIL has potential application value in cancer treatment.

[Antitumor efficacy of the recombinant Newcastle disease virus rNDV-IL15 on melanoma models].

In order to enhance the antitumor efficacy of recombinant Newcastle disease virus, rNDV-IL15 was rescued in this study. Recombinant plasmid prNDV-IL15 was constructed, and BHK21 cells were transfected with the recombinant plasmid. Finally, the recombinant Newcastle disease virus rNDV-IL15 was successfully rescued. The growth curves of these two recombinant viruses were determined. Murine melanoma B16F10 cells were infected with rNDV-IL15 at MOI of 0.1, and the expression level of IL15 in the supernatant was detected by ELISA. The antitumor efficacy of rNDV-IL15 and rNDV was compared in vitro and in vivo. Results showed that prNDV-IL15 was constructed and recombinant virus rNDV-IL15 was successfully rescued. The growth curve of rNDV-IL15 showed that the growth of rNDV-IL15 had not been changed after insertion of IL15 gene. Results showed that there was high level of IL15 expression in the supernatant of rNDV-IL5-infected B16F10 cells (1 044.3 +/- 27.7 ng x mL(-1)). rNDV-IL15 and rNDV significantly inhibited the growth of B16F10 cells in vitro in a time-dependent manner. However, there was no significant difference between them. In animal experiments, rNDV-IL15 efficiently suppressed tumor growth in vivo when compared with rNDV, and the difference was statistically significant. The results suggested that rNDV-IL15 is a more effective antitumor agent.

[Affinity optimization of an anti-hIL17A single-chain Fv antibody through error-prone PCR technique].

AIM: To optimize antibody affinity of a humanized anti-hIL17A single-chain Fv (scFV) antibody through error-prone polymerase chain reaction (PCR) so as to develop a therapeutic humanized antibody for the treatment of rheumatoid arthritis (RA). METHODS: Variable regions of heavy chain and light chain were subjected to random mutation by error-prone PCR and a scFv library was constructed by overlapping PCR. The library was screened for improved mutants by the bacterial inner membrane display technique and flow cytometry (FCM). Real-time PCR was used to detect neutralization effects of the purified scFv antibody mutants on mRNA expressions of IL-6 and IL-8 in HeLa cells stimulated by hIL17A. RESULTS: We obtained five mutants with improved affinity. FCM revealed that the affinity of three clones was greatly enhanced as compared with the parent clone. All mutants retained binding specificity to hIL17A. Real-time PCR results showed that all five mutants could block hIL17A stimulation of HeLa cells to express IL-6 and IL-8, and the neutralization effects were positively related to mutant affinity. CONCLUSION: Error-prone PCR technique is a feasible method for antibody affinity optimization in vitro, which is able to improve the affinity and neutralization capacity of antibody on the basis of its unchanged antigen binding specificity. This study provides potential drug candidates aimed for the treatment of rheumatoid arthritis and an alternative method of optimizing antibody affinity in vitro.