Abstract: Objective To investigate the relationship between STAT3 signal transduction pathway and proliferation as well as apoptosis and COX-2 expression of human esophageal carcinoma Eca-109 cell lines. Methods Eca-109 cells were treated with selective JAK2 inhibitor, AG490. MTT assay was used to detect the proliferation of Eca-109 cells, apoptosis was detected by flow cytometry, agarose gel electrophoresis of DNA and transmission electron micrograph (TEM). The protein expressions of JAK2、p-JAK2、p-Stat3 and COX-2 were examined by Western blot . RT-PCR was performed to detect the levels of COX-2 mRNA expression. Results AG490 significantly inhibited the growth of human Eca-109 cells in a dose and time-dependent manner and induced apoptosis. AG490 could inhibit the expressions of JAK2/STAT3 signal transduction pathway protein and down-regulate the expressions of p-JAK2 and p-Stat3 （P <0.05）, meanwhile, AG490 also reduced the expression of COX-2 mRNA and protein（P <0.05）. Conclusions AG490 may inhibit the proliferation and induce apoptosis of Eca-109 cells through decreasing expression of JAK2, STAT3 and COX-2. JAK2/STAT3 signaling pathway mediate AG490 induce apoptosis and proliferative inhibition in Eca-109 cells. This may be a new target of selective JAK2 inhibitor effect on Eca-109 cells.

Key words: Eca-109 cells, JAK2/STAT3, prolifertion, apoptosis, COX-2