Figure 4.

Serum impairs Gc action through activation of JNK. HeLa cells were transiently transfected with MMTV-Luc and GR overnight and then cultured in 10 or 50% serum. The cells were treated with Latrunculin B (A) or MAP kinase inhibitors (B) (ERK PD98059, p38 SB203580, and JNK SP600125) together with 100 nM Dex for 6 h before luciferase assay. The cells were transiently transfected with MMTV-Luc and GR, together with JNK (C) or ERK (D) expression vectors (or pcDNA5 as a control) overnight. The cells were transferred to 10 or 50% serum, treated with 100 nM Dex and 10 μM JNK inhibitor (SP600125) or ERK inhibitor (PD98059) for 6 h and then assayed for luciferase activity. HeLa cells were transfected with JNK or ERK expression vectors (or pcDNA5 as a control), cultured in 10 or 50% serum, and then treated with 100 nM Dex for 4 h before RNA extraction. Expression of MT1X (E), FKBP5 (F), GILZ (G), and PER1 (H) transcripts were measured by qRT-PCR (all normalised to GAPDH). The experiments were carried out in triplicate and repeated three times. Graphs show mean±s.e.m. *P<0.05. NS, not significant.