Association and contribution of ERK to IL-6-induced activation of signal transducer and activator of transcription in a human myeloma cell line

Objective To investigate the regulation effect of protein kinase ERK on the activation of transcription factor STAT3 in response to IL-6 in the Sko-00 7 human myeloma cell line. Methods Electrophoretic mobility shift assay (EMSA) and immunoprecipitation (IP) were used to show the activation of STAT3 and ERK in Sko-007 cells in the presence and absence of IL-6. Antisense oligonucloetides of ERK (ERK-A S) were transfected into Sko-007 cells to specifically inhibit the expressi on and activity of ERK. The changes in the activation of STAT3 in the trans fected cells were also exhibited by EMSA. Direct binding between STAT3 and ERK was analyzed by co-IP. Results Both STAT3 and ERK were activated in Sko-007 cells stimulated with IL-6. ERK-AS inhibited STAT3 activation by IL-6. Moreover, activated ERK co uld form a complex with STAT3 in Sko-007 cells. Conclusion ERK can bind STAT3 directly and be required for its maximal acti vation in Sko-007 cells stimulated by IL-6.