Figure 1.

SGK3 expression is controlled by estrogen/ER signaling. A) Parental MCF-7 cells pretreated with charcoal-stripped (CS) serum for 2 days were stimulated with 10nM β-estradiol (+E2). Cells grown in full serum were also included. Whole cell lysates were collected 24 hours after E2 addition for western blot analysis. An anti-actin antibody was used as loading control. mRNA was collected at the indicated time points for qPCR. B) Up-regulated SGK3 mRNA expression in response to estrogen treatment is a general feature of ER+ breast cancer cell lines. SGK3 mRNA expression following estrogen treatment in T47D and BT-474 cells from a previously published study [47] were plotted. C) SGK3 protein expression was suppressed when estrogen receptor was inhibited in breast cancer cells. Anti-SGK3 antibodies were used to western blot whole cell lysate from wildtype (WT) T47D and BT483 cells and their derivatives. NS, non-specific band was used as loading control. ED^R, resistant clones from estrogen deprivation treatment. Tam^R, resistant clones of tamoxifen-treated cells. D) SGK3 mRNA expression was suppressed when estrogen receptor was inhibited in MCF-7 endocrine resistance cells. E2, estrogen treatment.