Abstract:

Objective
To observe the effects of angiopoietin-2(Ang-2) on the expressions of Tie-2,PI3K,Akt gene and protein in the colon cancer cell line (HCT-8) and analyze the relationship between Ang-2 and PI3K/Akt.Methods Different  doses of Ang-2 （0,0.2,0.4,0.8,1.2,2.0， and 3.0 mg?L-1） were added into the DMEM medium of HCT-8 cell line and the effective stimulus concentration of Ang-2 on HCT-8 was selected by MTT.The cells were divided into four groups: normal control group (C group),serum-free culture medium group (SD group),Ang-2 group (SA2 group) and LY294002 group (SA2L group),the gene and protein expressions of Tie-2,PI3K and Akt were detected by RT-PCR and Western blotting.Results Different concentrations of exogenous Ang-2 showed various proliferation effects on the HCT-8 and the most effective dose of Ang-2 was 2 mg?L-1.Compared with SD group,the expressions of Tie-2,PI3K and Akt gene and protein in SA2 group were increased significantly (Tie-2: all P<0.01;PI3K: P<0.01 or P> 0.05;Akt: P<0.01);compared with SA2 group, the expressions of three genes and proteins in SA2L group were decreased significantly (Tie-2: P<0.05 or P<0.01;PI3K: P<0.05 or  P<0.01;Akt: P<0.01 and P<0.05). Conclusion Ang-2 can promote the proliferation of the colon cancer cells through the Ang-2/Tie-2/PI3K/Akt pathway which can be inhibited by LY294002.

Key words: angiopoietin-2;colon cancer cell line;proliferation;receptors,Tie-2;1-phosphatidy linositol 3-kinase;oncogene protein v-Akt