DNA-PK (IC50 = 2 nM); p110α (IC50 = 5.8 nM); p110γ (IC50 = 76 nM); p110δ (IC50 = 510 nM); p110β (IC50 = 1.3 μM); hsVPS34 (IC50 = 2.6 μM); PI3KC2β (IC50 = 1 μM); PI3KC2α (IC50 = 10 μM); mTORC1 (IC50 = 1 μM); mTORC2 (IC50 = 10 μM); ATM (IC50 = 2.3 μM); ATR (IC50 = 21 μM); PI4KIIIβ (IC50 = 50 μM)

PIK-75 also inhibits p110δ, PI3KC2β, mTORC1, ATM, hsVPS34, PI3KC2α, mTORC2, ATR and PI4KIIIβ with IC50s of 510 nM, ~1 μM, ~1 μM, 2.3 μM, 2.6 μM, ~10 μM, ~10 μM, 21 μM, ~50 μM, respectively[1].
With an IC50 of 1.2 M in L6 myotubes and 1.3 M in 3T3-L1 adipocytes, respectively, PIK-75 alone inhibits the phosphorylation of Thr 308[1].
With an IC50 value of 78 nM, PIK-75 (1–1000 nM; 5 min) inhibits the insulin-induced phosphorylation of PKB on Ser473 and Thr308 in CHO-IR cells in a dose-dependent manner.
Through inducing apoptosis in pancreatic cancer cells, PIK-75 (0.1-1000 nM; 48 hours) prevents their growth and survival[3].
In addition, pancreatic cancer MIA PaCa-2 and AsPC-1 cells form fewer colonies when PIK-75 (0.1–1000 nM) is present[3].

PIK-75 (2 mg/kg) potentiates anticancer activity of Gemcitabine (20 mg/kg) in vivo. Gemcitabine (20 mg/kg) or PIK-75 (2 mg/kg) alone both significantly slow tumor growth. The combination of PIK-75 and Gemcitabine clearly has a positive effect because it significantly slows the growth of tumors in vivo while having no negative effects on the body weights of mice[3].

The PI3K inhibitor PIK-75 is dissolved at 10 mM in dimethyl sulfoxide and stored at −20°C until use. PI3K enzyme activity is determined in 50 μL of 20 mM HEPES, pH 7.5, and 5 mM MgCl2 containing 180 μM phosphatidyl inositol, with the reaction started by the addition of 100 μM ATP (containing 2.5 μCi of [γ-32P]ATP). After a 30-minute incubation at room temperature, the enzyme reaction is stopped by the addition of 50 μL of 1 M HCl. Phospholipids are then extracted with 100 μL of chloroform/methanol [1:1 (v/v)] and 250 μL of 2 M KCl followed by liquid scintillation counting. Inhibitors are diluted in 20% (v/v) dimethyl sulfoxide to generate a concentration versus inhibition of enzyme activity curve, which is then analyzed with the use of Prism version 5.00 for Windows to calculate the IC50. For kinetic analysis, a luminescent assay measuring ATP consumption is used. PI3K enzyme activity is determined in 50 μL of 20 mM HEPES, pH 7.5, and 5 mM MgCl2 with PI and ATP at various concentrations. After a 60-minute incubation at room temperature, the reaction is stopped by the addition of 50 μL of Kinase-Glo followed by a further 15-minute incubation. Luminescence is then read using a Fluostar plate reader. Results are analyzed using Prism.

Mitochondrial activity is assessed after stimulation with TGFβ with or without inhibitors for 48 hours using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay. Harvested washed cells are resuspended in DMEM-lO% FCS and aliquoted (500 μL) into 24-well cluster plates prior to serial dilution (1:2) in duplicates. To each well, 100 μL of an appropriate MTT concentration (dissolved in PBS and filtered through a 0.2 μm filter before use to remove any blue formazan product) is added immediately after diluting the cells, which are then incubated for 3.5 hours at 37 °C. The resulting blue formazan product is solubilized overnight (16 hours) at 37 °C by the addition of 500 μL of 10% sodium dodecyl sulfate　(SDS) in 0.01 M HCl to each well. A sample (150　μL)　from each duplicate well is transferred to a 96-well　microplate, and the optical density determinedby automated spectrophotometry against a reagent blank (no　cells).　Absorbance is measured at a test wavelength of 570 nm and a reference wavelength of 690 nm. For each primary cell culture, results from three to six wells from each treatment are averaged, and data are expressed as absorbance 570 to 690 nm. Cells: A2780, A2780/cp70, 2780AD, HCT116, HT29, WIL, CALU-3, MCF7, PC3 and HS852 cells.

[1]. A pharmacological map of the PI3-K family defines a role for p110alpha in insulin signaling. Cell. 2006 May 19;125(4):733-47.

[2]. Evidence for functional redundancy of class IA PI3K isoforms in insulin signalling. Biochem J. 2007 Jun 15;404(3):449-58.

[3]. Inhibition of NRF2 by PIK-75 augments sensitivity of pancreatic cancer cells to gemcitabine. Int J Oncol. 2014 Mar;44(3):959-69.

N-[(6-bromo-3-imidazo[1,2-a]pyridinyl)methylideneamino]-N,2-dimethyl-5-nitrobenzenesulfonamide is a sulfonamide.
PIK-75 is a preferential p110 alpha/gamma PI3K inhibitor.

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Phosphoinositide 3-kinases (PI3-Ks) are an important emerging class of drug targets, but the unique roles of PI3-K isoforms remain poorly defined. We describe here an approach to pharmacologically interrogate the PI3-K family. A chemically diverse panel of PI3-K inhibitors was synthesized, and their target selectivity was biochemically enumerated, revealing cryptic homologies across targets and chemotypes. Crystal structures of three inhibitors bound to p110gamma identify a conformationally mobile region that is uniquely exploited by selective compounds. This chemical array was then used to define the PI3-K isoforms required for insulin signaling. We find that p110alpha is the primary insulin-responsive PI3-K in cultured cells, whereas p110beta is dispensable but sets a phenotypic threshold for p110alpha activity. Compounds targeting p110alpha block the acute effects of insulin treatment in vivo, whereas a p110beta inhibitor has no effect. These results illustrate systematic target validation using a matrix of inhibitors that span a protein family.[1]

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Recent genetic knock-in and pharmacological approaches have suggested that, of class IA PI3Ks (phosphatidylinositol 3-kinases), it is the p110alpha isoform (PIK3CA) that plays the predominant role in insulin signalling. We have used isoform-selective inhibitors of class IA PI3K to dissect further the roles of individual p110 isoforms in insulin signalling. These include a p110alpha-specific inhibitor (PIK-75), a p110alpha-selective inhibitor (PI-103), a p110beta-specific inhibitor (TGX-221) and a p110delta-specific inhibitor (IC87114). Although we find that p110alpha is necessary for insulin-stimulated phosphorylation of PKB (protein kinase B) in several cell lines, we find that this is not the case in HepG2 hepatoma cells. Inhibition of p110beta or p110delta alone was also not sufficient to block insulin signalling to PKB in these cells, but, when added in combination with p110alpha inhibitors, they are able to significantly attenuate insulin signalling. Surprisingly, in J774.2 macrophage cells, insulin signalling to PKB was inhibited to a similar extent by inhibitors of p110alpha, p110beta or p110delta. These results provide evidence that p110beta and p110delta can play a role in insulin signalling and also provide the first evidence that there can be functional redundancy between p110 isoforms. Further, our results indicate that the degree of functional redundancy is linked to the relative levels of expression of each isoform in the target cells.[2]

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We describe the potential benefit of PIK-75 in combination of gemcitabine to treat pancreatic cancer in a preclinical mouse model. The effect of PIK-75 on the level and activity of NRF2 was characterized using various assays including reporter gene, quantitative PCR, DNA-binding and western blot analyses. Additionally, the combinatorial effect of PIK-75 and gemcitabine was evaluated in human pancreatic cancer cell lines and a xenograft model. PIK-75 reduced NRF2 protein levels and activity to regulate its target gene expression through proteasome-mediated degradation of NRF2 in human pancreatic cancer cell lines. PIK-75 also reduced the gemcitabine-induced NRF2 levels and the expression of its downstream target MRP5. Co-treatment of PIK-75 augmented the antitumor effect of gemcitabine both in vitro and in vivo. Our present study provides a strong mechanistic rationale to evaluate NRF2 targeting agents in combination with gemcitabine to treat pancreatic cancers.[3]

C16H14BRN5O4S

452.28

450.994

C, 42.49; H, 3.12; Br, 17.67; N, 15.48; O, 14.15; S, 7.09

372196-67-3

PIK-75 hydrochloride;372196-77-5

10275789

Light brown to brown solid powder

1.7±0.1 g/cm3

1.701

3.84

0

7

4

27

679

0

BrC1=CN2C(/C=N/N(C)S(C3C=C([N+]([O-])=O)C=CC=3C)(=O)=O)=CN=C2C=C1

QTHCAAFKVUWAFI-DJKKODMXSA-N

InChI=1S/C16H14BrN5O4S/c1-11-3-5-13(22(23)24)7-15(11)27(25,26)20(2)19-9-14-8-18-16-6-4-12(17)10-21(14)16/h3-10H,1-2H3/b19-9+

N-[(E)-(6-bromoimidazo[1,2-a]pyridin-3-yl)methylideneamino]-N,2-dimethyl-5-nitrobenzenesulfonamide

PIK 75; PIK75; PIK-75; 372196-67-3; 945619-31-8; UNII-9058I8S63D; (E)-N'-((6-bromoimidazo[1,2-a]pyridin-3-yl)methylene)-N,2-dimethyl-5-nitrobenzenesulfonohydrazide; 9058I8S63D; PIK-75

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)