Figure 4.

RASAL1 regulates HIF-1α expression through ROS-ERK/Akt pathway. (A) MCF-7 and MDA-MB-231 cells were transfected with scramble and shRASAL1 lentivirus for 24 h, then treated with 10 mmol/l NAC for 36 h. Total lysates were harvested for the assay of RASAL1, HIF-1α, ERK1/2, Akt, phosphorylated ERK1/2 (P-ERK1/2) and phosphorylated Akt (P-Akt) protein levels using western blot analysis. (B) RASAL1 expression vector increased the luciferase activity of HIF-1α 3′-UTR by in MCF-7 and MDA-MB-231 cells, while 10 mmol/l NAC inhibited the effect of shRASAL1. Luciferase activity was determined 60 h after transfection. Each bar represents the mean ± standard error of the mean. The results were reproduced in three independent experiments. ***P<0.001. RASAL1, RAS protein activator-like 1; HIF-1α, hypoxia inducible factor-1α; ROS, reactive oxygen species; ERK, extracellular signal-regulated kinase; shRASAL1, short hairpin RASAL1; NAC, N-acetyl cysteine.