Effects of inhibiting JAK on invasion and metastasis of the human breast cancer cells through ERK signaling transduction pathway

Objective: To explore the effects of Janus activated kinase (JAK) inhibitor AG490 on the phosphorylation of extracellular signal regulated protein kinase (ERK) in human breast cancer cells MDA-MB-231 and the roles of JAK in the invasion and metastasis of the human breast cancer cells through ERK signaling transduction pathways.Methods: MDA-MB-231 cells were treated with 20 (mol/L, 40 (mol/L, 80 (mol/L Janus kinase inhibitor AG490 for 24, 48 and 72 h. Proliferation and adhesion of MDA-MB-231 cells to matrigel were measured with MTT assay. When treated with 40 (mol/L AG490 for 24 h, the expressions of P-ERK and MMP-9 of cells were detected by Western-blot and invasion and metastasis of MDA-MB-231 cells were evaluated with transwell chamber.Results: After being treated with 20 (mol/L, 40 (mol/L, 80 (mol/L AG490 for 24, 48 and 72 h, the proliferation of MDA-MB-231 cells was inhibited in a dose-and time-dependent manner. MDA-MB-231 cells treated with 40 (mol/L AG490 for 30, 60, 90 and 120 min resulted in the increasing adhesion of cells to Matrigel in a time-dependent manner. However, capacity of adhesion in the group treated with AG490 was significantly decreased in comparison with the control group (P<0.01). The expression level of P-ERK and MMP-9 were decreased when treated with AG490. After treatment with 40 (mol/L AG490, in invasion assay, the number of cells in AG490 treated group to migrate to filter coated with Matrigel was reduced compared with control group (P<0.05). Meanwhile, in migration assay, the number of cells in AG490 treated group to migrate to filter was also decreased compared with control group (P<0.05).Conclusion: Our study indicates that JAK kinase could affect the activity of ERK signal transduction pathway through the phosphorylation of ERK. The inhibitory effects of JAK kinase on MMP-9 expression and invasion of breast cancer cells were associated with the down-regulation of the ERK signaling pathway.