MEKs, which are members of the MAPKK family, can activate both ERK1 and ERK2 by catalyzing the phosphorylation on T202/Y204. Also MEK itself can be phosphorylated and activated through Ras when the upstream signaling is activated by extracellular stimuli, including growth factors, hormones etc.. U0126 is a selective MEK1/2 inhibitor with IC50 value of 70/60nM, but not ERK or Raf[1][2]. Co-treatment with U0126 for 15min at concentration ranging in 1nM-10μM caused inhibition of PMA-induced p-ERK, the target of MEK1/2 in a dose-dependent manner in COS-7 cells. An in vitro study showed that U0126 represented much more potency to both wild type and ΔN3-S218E/S222D MEK compared with the another MEK1/2 inhibitor, PD98059[2]. An in vivo study showed that U0126 is brain-permeable. Intravenous injection with U0126 at dose of 100mg/kg could reduce p-ERK1/2 in hippocampus after 10 min of reperfusion after 3.5 min bilateral carotid artery occlusion in male gerbils. Intravenous administration of U0126 at dose of 100-200mg/kg showed protective effect on the hippocampus against forebrain ischemia in male gerbils. Moreover, treatment with U0126 at 3 hours post ischemia significantly reduced volume after transient focal cerebral ischemia, accompanied with reduced p-ERK in the damaged brain areas[3]. Also, it has been reported that U0126 helped maintain human pluripotent stem cells[4].
作用机制
U0126 is a non-competitive inhibitor of MEK1/2, which can bind a common or two overlapping sites on MEK.[2]
U0126-EtOH 细胞实验
Cell Line
Concentration
Treated Time
Description
References
MEL10 cells
10 µM
5 days
U0126 induced cyclin D1-negative senescence.
Cell Death Differ. 2013 Sep;20(9):1241-9.
TE671 cells
40 μM
7 days
U0126 significantly reduced the number of CD133 and CXCR4 positive cells in TE671 cells and inhibited rhabdosphere formation.
Mol Cancer. 2016 Feb 20;15:16.
RD cells
10 μM
15 days
Inhibition of the MEK/ERK pathway in RD cells significantly reduced rhabdosphere formation and downregulated the expression of stem cell markers CD133, CXCR4, and Nanog, while enhancing ALDH, MAPK p38, and differentiative myogenic markers.
Mol Cancer. 2016 Feb 20;15:16.
Canine tracheal smooth muscle cells
15 μM or 30 μM
≥45 min
U0126 increased the force-fluctuation-induced relengthening (FFIR) of acetylcholine-contracted canine tracheal smooth muscle strips in a concentration-dependent manner, and this effect was negatively correlated with the phosphorylation of high-molecular-weight caldesmon (h-caldesmon).
Eur Respir J. 2010 Sep;36(3):630-7.
HT-p16 cells
10 µM
24 h
U0126 completely eliminated cyclin D1 accumulation, making it undetectable.
Cell Death Differ. 2013 Sep;20(9):1241-9.
HT-p21 cells
10 µM
24 h
U0126 completely eliminated cyclin D1 accumulation, making it undetectable.
Cell Death Differ. 2013 Sep;20(9):1241-9.
mouse primary cultured cortical neurons
10 µM
U0126 dramatically inhibited neuronal cell death by exposure to SNP, with a maximum inhibition at 10 µM.
Proc Natl Acad Sci U S A. 2001 Sep 25;98(20):11569-74.
Proc Natl Acad Sci U S A. 2001 Sep 25;98(20):11569-74.
U0126-EtOH 动物实验
Species
Animal Model
Administration
Dosage
Frequency
Description
References
NOD/SCID mice
Embryonal rhabdomyosarcoma model
Intraperitoneal injection
25 μM/kg
3 times per week for 4 weeks
Intraperitoneal administration of U0126 significantly inhibited tumor growth induced by rhabdosphere cells, delayed tumor progression time, and reduced tumor volume.
Mol Cancer. 2016 Feb 20;15:16.
Gerbils
Forebrain ischemia model
I.v. administration
100 mg/kg
Single injection, 10 min before ischemia
U0126 reduced the loss of CA1 pyramidal cells at 7 days, protecting the hippocampus against forebrain ischemia.
Proc Natl Acad Sci U S A. 2001 Sep 25;98(20):11569-74.
Inhibitory concentration against AP-1 transcription in COS-7 cells， IC50=1 μM.
15006386
HCT116 cells
Function assay
Ability of compound to inhibit anchorage independent colony formation (soft agar growth assay) in HCT116 cells, IC50=19.4 μM.
15225706
HeLa cells
Function assay
Inhibition of EGF-stimulated Elk1-luciferase reporter assay in HeLa cells, IC50=0.29 μM.
15225706
mouse RAS-3T3 cells
10-40 μM
Function assay
Inhibition of MEK-mediated ERK1/2 phosphorylation in mouse RAS-3T3 cells at 10 to 40 uM by ELISA.
24507826
rat PC12 cells
10 μM
Function assay
1 h
Activation of Nrf2/ARE in rat PC12 cells assessed as HO-1 protein induction at 10 uM after 5 hrs pretreated with JNK inhibitor SP600125 for 1 hr before compound addition by Western blot analysis
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