GSK2334470

GSK2334470 inhibits PDK1 from activating full-length Akt1 in the presence of PtdIns(3,4,5)P₃-containing lipid vesicles or a mutant of Akt1 lacking the PH domain (ΔPH-Akt1) with IC50 of ~10 nM. GSK2334470 also similarly inhibits PDK1 from phosphorylating the PDKtide peptide substrate with IC50 of ~10 nM. GSK2334470 (0.1 μM–0.3 μM) induces significant dose-dependent inhibition of endogenous NDRG1 with over 50% reduction in phosphorylation in HEK-293 cells. GSK2334470 (30 nM) induces a significant dose-dependent inhibition of the T-loop phosphorylation of each SGK isoform in HEK-293 cells. GSK2334470 (1 μM) inhibits hydrophobic motif phosphorylation of S6K1 to a similar extent as T-loop phosphorylation in HEK-293 cells. GSK2334470 (3 μM) also suppresses S6K1 activity and phosphorylation induced by IGF1 stimulation of serum-starved HEK-293 cells. GSK2334470 (3 μM) markedly inhibits the phosphorylation of several Akt substrates [FoxO (forkhead box O), GSK3 and PRAS40]. GSK2334470 (3 μM) also induces near maximal inhibition of Akt1 activity and phosphorylation within 5 min, and Akt substrate phosphorylation (FoxO, GSK3 and PRAS40) is inhibited at a slightly later time point (10 min). GSK2334470 (0.3 μM) significantly inhibits phosphorylation of Akt or PRAS40/GSK3 in PDK1K^465E/K465E knock-in but not wild-type ES cells. GSK2334470 (1 μM) effectively suppresses SGK1 activity as judged by the inhibition of NDRG1 phosphorylation in U87 glioblastoma cells. GSK2334470 (1 μM) also potently suppresses activation of S6K1 (Figure 7B) as well as SGK1 in MEF (mouse embryonic fibroblast) cells. GSK2334470 (0.1 μM) induces ~50% inhibition of RSK2 activity in HEK-293 cells. ^[1]

GSK2334470 (30 µM) suppresses U46619 induced Ca²⁺-sensitized force in α-toxin permeabilized rabbit pulmonary artery SM. GSK2334470 (30 µM) results in a significant decrease in the contractile force in response to [Ca²⁺]. ^[2]

GSK2334470 (1 μM) results in total abrogation of the EGF-induced intracellular calcium increase and inositol phosphates accumulation in MDA-MB-231 cells. GSK2334470 (1 μM) inhibits PLCγ1 Tyr783 phosphorylation in MDA-MB-231 cells. ^[3]

GSK2334470 is a highly specific and potent inhibitor of PDK1.

• Kinase activity assays

  Endogenous Akt, S6K and RSK are immunoprecipitated from 0.1 mg to 1 mg of cell lysate for 2 hours at 4℃ on a vibrating platform using 3 μg–5 μg of the indicated antibodies. For the SGK activity assays, 150 μg of transfected lysate is incubated with 5 μg of glutathione–Sepharose for 3 hours at 4℃. The immunoprecipitates are washed twice with lysis buffer containing 0.5 mM NaCl, followed by two washes with kinase buffer. Kinase reactions are initiated by a reaction mixture to bring the final concentrations of the reaction components to 0.1 mM [γ-³²P]ATP (~200 c.p.m./pmol), 5 mM magnesium acetate, 0.1% 2-mercaptoethanol and 30 mM Crosstide peptide (GRPRTSSFAEGKK). Reactions are carried out for 20 min at 30℃ on a vibrating platform and stopped by spotting the reactions on to P81 phosphocellulose paper. Cerenkov counting is done after washing the papers in phosphoric acid, rinsing in acetone and air-drying. One unit of activity is defined as that which catalysed the incorporation of 1 nmol of [³²P]phosphate into the substrate over 1 hour.

• Cell lines

  MDA-MB-231 cells

• Concentrations

  1 µM

• Incubation Time

  30 minutes

• Method

  Cells were incubated with 1 µM of GSK2334470 for 30 minutes. Cells treated with DMSO were used as control.

• Animal Models

  Nude mice

• Dosages

  100 mg/kg

• Administration

  i.p.