Objective To explore the effect of NGAL knockdown by NGAL siRNA encapsulated with urocanic acid-modified chitosan nanoparticles (UAC).MethodsNGAL siRNA encapsulated by UAC and chitosan (CTS) respectively, which were then used to transfect human colon cancer cell lines HT29.The expression level of NGAL protein were detected by Enzyme Linked Immunosorbent Assay(ELISA).ResultsThe ELISA study revealed that the expression level of NGAL protein in UAC group(average 0.583μg/L) was significantly lower than in CTS group (average 0.772μg/L) and control group(average 1.071μg/L) (P<0.05).ConclusionThe NGAL expression of mRNA and protein in HT29 cells could be down-regulated by siRNA encapsulated by UAC.

Objective Optimization the demethylation reaction conditions in the process of synthesizing carbidopa, to determine the optimal production process. Methods With methyldopa as raw material, by methylation,amidation,fol-lowed degradation,demethylation,and then to obtain carbidopa. In the last step of demethylation reaction,with car-bidopa yield as the evaluation index,using four factors and three levels orthogonal design,to optimize the process con-ditions. Results The optimal process conditions for demethylation that is to add 10-fold amount of 36%(g/mL) hy-drochloric acid, and the reaction is remained for 3.5 hours. Conclusion The optimum process is simple,economical, reasonable and convenient for controlling. This study provide experimental basis for industrial production.

OBJECTIVETo explore the impact of neutrophil gelatinase-associated lipocalin (NGAL) knockdown by NGAL siRNA encapsulated with urocanic acid-modified chitosan nanoparticles (UAC) on the proliferation, migration and apoptosis of human colon cancer cells.

METHODSNGAL siRNA was encapsulated by UAC and chitosan (CTS) respectively, and then was transfected into human colon cancer cell lines HT29. The NGAL mRNA was detected by real-time quantitative PCR (RT-QPCR). Relationships of NGAL gene silencing with the proliferation, migration and apoptosis of HT29 cell were analyzed.

RESULTSUnder the fluorescence microscope, the transfection efficiency of siRNA in UAC group was (37.52±7.17)%, which was significantly higher than (11.32±3.39)% in CTS group (t=6.102, P=0.005). Forty-eight hours after transfection, RT-QPCR examination showed that the level of NGAL mRNA expression was 0.350 in UAC group and 0.529 in CTS group with significant difference (t=-3.743, P=0.02), meanwhile both levels were significantly lower as compared to control group(F=163.538, P<0.001). Proliferation analysis revealed that after silencing NGAL gene, proliferation rate of UAC group and CTS group was slightly lower than control group, and no significant differences were found (F=9.520, P=0.438). However, migration assay demonstrated that the 24-hour migration rate of UAC group and CTS group was significantly lower than that of control group (F=6.756, P=0.029), meanwhile the migration rate of UAC group was slightly lower than that of CTS group [(77.90±7.14)% vs. (87.67±3.98)%, t=-1.704, P=0.164]. Apoptosis detection revealed that the apoptosis rate in UAC group was significantly higher than that in CTS group and the control group 2 days after transfection [(15.800±1.054)% vs. (12.900±0.656)%, (11.933±1.914)%, F=7.004, P=0.027].

CONCLUSIONSThe encapsulated ability and transfection efficiency of chitosan modified by urocanic acid elevate significantly. Silencing NGAL gene by UAC carrier can down-regulate the expression of NGAL mRNA in HT29 colon cell line, inhibit their migration and facilitate their apoptosis.