ABSTRACT
@#【Objective】 To investigate the relationship between the expression of PRDX3 （thioredoxin-dependent peroxide reductase）and the occurrence and development of ccRCC （clear cell renal cell carcinoma）. 【Methods】 The expression of PRDX3 was first verified in 16 cases of ccRCC tissues and adjacent normal tissues. In the present study ， according to the PRDX3 over-expression level，we established the stable PRDX3 overexpression cell lines and knockdown cell lines in 786-O cell lines. We detected the growth rate of tumor cells after overexpression and knockdown of PRDX3. Interaction proteins with PRDX3 were searched by anti-flag pull-down test combined with LC- MS/MS technique. The interaction between PRDX3 and PRDX1（peroxiredoxin 1）was preliminarily explored.【Results】The western blot results showed that PRDX3 were down- regulated in 14 out of 16 ccRCC tissue samples about 1.78 times. Stable PRDX3 overexpression and knockdown cell lines and those control group were successfully established［786O- PRDX3（+）and 786O- PRDX3（-），786O- PRDX3 KN and 786O- PRDX3 NCi］. PRDX3 expression in 786O- PRDX3（+）was 2.1 times higher than 786O- PRDX3（-）at mRNA level and 1.8 times at protein level. PRDX3 expression in 786O- PRDX3 KN was 0.48 times lower than 786O-PRDX3 NCi at mRNA level and 0.51 times at protein level. The cell growth rate of 786O-PRDX3 （+）cell lines was significantly lower than that of 786O-PRDX3（-）. Meanwhile ，there was no significant difference in 786O-PRDX3 KN and NCi cell lines. Pull-down results shows that PRDX3 may interact with PRDX1 through disulfide bond and the binding sites of those two proteins were identified respectively.【Conclusion】PRDX3 was down- regulated expression in renal clear cell carcinoma and the interaction with PRDX1 may be involved in the occurrence and development of tumor. Increasing the expression level of PRDX3 can significantly reduce the growth rate of tumor cells. Based on PRDX3 ，it is possible to develop targeted drugs for treating renal clear cell carcinoma.
ABSTRACT
Five pentacyclic triterpenoids isolated from Campsis grandiflora were tested for insulin-mimetic and insulin-sensitizing activity. The compounds enhanced the activity of insulin on tyrosine phosphorylation of the IR (insulin receptor) beta-subunit in CHO/IR (Chinese-hamster ovary cells expressing human IR). Among the compounds tested, CG7 (ursolic acid) showed the greatest enhancement and CG11 (myrianthic acid) the least. We characterized the effect of CG7 further, and showed that it acted as an effective insulin-mimetic agent at doses above 50 mug/ml and as an insulin-sensitizer at doses as low as 1 mug/ml. Additional experiments showed that CG7 increased the number of IRs that were activated by insulin. This indicates that a major mechanism by which CG7 enhances total IR auto-phosphorylation is by promoting the tyrosine phosphorylation of additional IRs. CG7 not only potentiated insulin-mediated signalling (tyrosine phosphorylation of the IR beta-subunit, phosphorylation of Akt and glycogen synthase kinase-3beta), but also enhanced the effect of insulin on translocation of glucose transporter 4 in a classical insulin-sensitive cell line, 3T3-L1 adipocytes. The results of the present study demonstrate that a specific pentacyclic triterpenoid, CG7, exerts an insulin-sensitizing effect as an IR activator in CHO/IR cells and adipocytes. The enhancement of insulin activity by CG7 may be useful for developing a new class of specific IR activators for treatment of Type 1 and Type 2 diabetes.
