[Inhibition of angiogenesis in pancreatic carcinoma by cyclooxygenase-2 antisense oligodeoxynucleotides]

To investigate the effect of cyclooxygenase-2 antisense oligodeoxynucleotides (COX-2 AS-ODNs) on the angiogenesis in pancreatic carcinoma and to evaluate the intermediary effect of prostaglandin 2 in this process.

Specific targeting COX-2 AS-ODNs were designed and synthesized, and transfected into the PC3 human pancreatic carcinoma cells cultured in vitro. Fluorescence microscopy was used to observe the PC3 cells 0.12. 24, 40, and 72 hours after the transfection. the second cultured PC3 cells were divided into 5 groups: control group, Lipo group (transfected with Lipofectin only), C1 group (transfected with 1 micro g COX-2 AS-ODN + Lipo/well), C2 group (transfected with 2 micro g COX-2 AS-ODN + Lipo/well), and C3 group (transfected with 3 micro g COX-2 AS-ODN + Lipo/well). RT-PCR was used to observe the expression of COX-2 mRNA in the PC3 cells. The third batch of PC3 cells were transfected with 3 micro g COX-2 AS-ODN + Lipo/well, and the expression of COX-2 mRNA was observed 0, 12, 24, 48, and 72 hours later by RT-PCR. 3 micro g COX-2 AS-ODN + Lipo/bottle and 9 micro g COX-2 AS-ODN + Lipo/bottle were added into the cultured PC3 cells and Western blotting was used to observe the expression of COX-2 protein 24 hours later. 24 chicken eggs were inoculated with PC3 cells into the chorio-allantoic membrane and then divided equally into 5 groups; control group, Lipo group, COX-2 AS-ODN + Lipo group, and COX-2 AS-ODN + Lipo + PGE2 group. Leica microscopy was used to observe the angiogenesis in the transplanted carcinoma.

RT-PCR showed that the downregulation of expression of COX-2 mRNA in the PC3 cells with the increase of the COX-2 AS-ODN concentration, peaking at the concentration of 0.2 micro mol/L. The effect of COX-2 AS-ODN was strongest by the 12th hour after transfection and then began to decrease and basically disappeared 48 hours after. Western blotting showed that COX-2 AS-ODN, especially that of the concentration of the expression of 9 micro g/bottle, inhibited the expression of COX-2 AS-ODN. The angiogenesis of the transplanted carcinoma in the eggs was significantly inhibited in the Lipo + COX-2 AS-ODN group, the density of newly generated vessels in the Lipo + COX-2 AS-ODN + PGE2 group was between those of the other 2 groups.

COX-2 AS-ODN significantly inhibits the angiogenesis in the pancreatic carcinoma. Endogenous COX-2 AS-ODN may play an important role in such a process and PGE2 may play an intermediate role therein.