Effect Of Parg Gene Silenced Via Rna Interference On Liver Metastasis Of Colorectal Carcinoma CT26Cell In Mice

Objective: The study was to investigate the effect of Poly(ADP-ribose)glycohydrolase (PARG) gene silenced via RNA interference on livermetastasis of CT26cell line in mice.Methods: Compared the migration and invasion abilities of PARGgene silenced CT26cells with untransfected CT26cells by cell invasionassay and cell-matrix adhesion assay. Metastasis models of BALB/c micewere established by intrasplenic inoculation of untransfected CT26cells,CT26cell transfected with empty vector and CT26cell transfected withPARG-shRNA respectively. The changes of splenic transplantation tumors,liver metastases and survival time were observed. The expressions of PARG,PARP, NF-κB, integrin-β1, MMP-9and MMP-2in vitro and in vivo weremeasured by Western blot analysis. The effect of PARG on activities ofMMP-9and MMP-2in various groups supernatant were detected byzymography．Results:1. The results of cell invasion assay and cell-matrix adhesionassay showed that PARG silencing lead to significant reduction in the number of CT26cells, that migrated to lower surface of the membrane(p<0.5) and adhered to fibronectin (p<0.5), compared to the two controlgroups.2. Succeeded to construct experimental metastasis model.14daysafter inoculation, the splenic transplantation tumors were observed in threegroups. But the average volume of splenic transplantation tumors andgrading of liver metastasis nodules were significantly less than that of twocontrol groups (p<0.5). The Kaplan-Meier curves showed that PARGsilencing can efficiently prolong the survival time of mice.3. The expressions of integrin-β1, MMP-9and MMP-2in CT26cellslacking PARG were lower than that of two control groups (p<0.5). Similarresults were attained in activities of MMP-9and MMP-2in various groupssupernatant (p<0.5).4.The expressions of PARG, PARP, NF-κB, integrin-β1, MMP-9andMMP-2in splenic transplantation tumors were significantly reduced inPARG-shRNA treated group in comparison with other two control groups(p<0.5).Conclusion:1.PARG silenced via RNA interference can suppress themigration and invasion abilities of CT26cells. In addition, PARG silencedcan inhibit the formation of splenic transplantation tumors and livermetastases. It suggests that PARG may play an important role in tumorinvasion and metastasis. 2.The inhibitory effect of PARG silenced on CT26cell adhesion,invasion and formation of liver metastases may be attributed by reductionof integrin-β1, MMP-9and MMP-2via its downstream regulation ofPARP and NF-κB-dependent genes.