Experimental research of neutrophil gelatinase-associated lipocalin siRNA encapsulated by urocanic acid-coupled chitosan on colon cancer cells / 中华胃肠外科杂志

ABSTRACT

<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>NGAL 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.</p><p><b>RESULTS</b>Under 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].</p><p><b>CONCLUSIONS</b>The 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.</p>