EGFR (IC50 = 0.7 nM)

PD 168393 docks into EGFR TK's ATP binding pocket. In A431 cells, continuous exposure to PD168393 completely stops EGF-dependent receptor autophosphorylation, and the suppression continues even after 8 hours in compound-free medium. With an IC50 of 5.7 nM, PD168393 prevents heregulin-induced tyrosine phosphorylation in MDA-MB-453 cells. PD168393 is not active against PKC, insulin, PDGF, or basic FGFR TKs. With an IC50 of 1-6 nM, PD168393 suppresses EGF-mediated tyrosine phosphorylation in HS-27 human fibroblasts but has no effect on PDGF- or FGF-mediated tyrosine phosphorylation.[1] In 3T3-Her2 cells, PD168393 exhibits a swift and strong suppression of Her2-induced tyrosine phosphorylation, with an IC50 of approximately 100 nM. In 3T3-Her2 cells, D168393 also prevents PLCγ1/Stat1/Dok1/δ-catenin from being phosphorylated, with the exception of Fyb.[2]

PD168393 (intraperitoneal injection; 58 mg/kg; once daily; days 10-14, 17-21, and 24-28) is efficacious in vivo, exhibiting 115% tumor growth inhibition in human epidermoid carcinoma xenografts in mice following a 15-day treatment period.

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In the present study, researchers evaluated the effects of EGFR inhibitor, PD168393 (PD), on the myelination in mouse contusive SCI model. It was found that expression of myelin basic protein (MBP) in the injured spinal cords of PD168393 treated mice was remarkably elevated. The density of glial precursor cells and oligodendrocytes (OLs) was increased and the cell apoptosis in lesions was attenuated after PD168393 treatment. Moreover, PD168393 treatment reduced both the numbers of OX42 + microglial cells and glial fibrillary acidic protein + astrocytes in damaged area of spinal cords. They thus conclude that the therapeutic effects of EGFR inhibition after SCI involves facilitating remyelination of the injured spinal cord, increasing of oligodendrocyte precursor cells and OLs, as well as suppressing the activation of astrocytes and microglia/macrophages[3].

PD168393 is an potent, cell-permeable, irreversible EGFR inhibitor that irreversibly alkylates Cys-773. It is inactive against PDGFR, FGFR, PKC, and insulin. Its IC50 is 0.70 nM. goal: EGFR IC 50 = 0.7 nM (1) PD 168393 has >9-fold higher potency than PD 174265 in inhibiting EGFr autophosphorylation in A431 human epidermoid carcinoma cells. (2) In cardiomyocytes stimulated by lipopolysaccharide (LPS), PD 168393 reduces TNF-α production and phosphorylation of ERK1/2 and p38. (3) At concentrations as low as 0.03 umol/L, PD168393 totally inhibits the phosphorylation of AKT and ERK. (4) In ErbB2 positive lung and breast cancer cell lines, PD168393 may cause apoptosis and suppress cell growth. (5) The inhibition of phospho-p44/42 ERK indicated that PD168393 interfered with MEK1/p44/42 ERK signaling in HaCaT cells.

(1) PD 168393 has >9-fold higher potency than PD 174265 in inhibiting EGFr autophosphorylation in A431 human epidermoid carcinoma cells. (2) In cardiomyocytes stimulated by lipopolysaccharide (LPS), PD 168393 reduces TNF-α production and phosphorylation of ERK1/2 and p38. (3) At concentrations as low as 0.03 umol/L, PD168393 totally inhibits the phosphorylation of AKT and ERK. (4) In ErbB2 positive lung and breast cancer cell lines, PD168393 may cause apoptosis and suppress cell growth.

Athymic nude mice with A431 human epidermoid carcinoma
58 mg/kg
i.p.

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In Vivo Efficacy.[1]
To illustrate the advantage of irreversibility, a direct comparison between PD168393 (irreversible) and 174265 (reversible) for target modulation in viable cells is shown in Table 2. PD168393 inhibited EGFr autophosphorylation in A431 human epidermoid carcinoma cells with >9-fold greater potency than PD 174265. An even greater difference was seen against heregulin-mediated tyrosine phosphorylation in MDA-MB-453 human breast carcinoma cells, where PD168393 was >30-fold more potent. The therapeutic advantage of irreversible inhibition is illustrated quite dramatically in Fig. 6a, which shows a head-to-head comparison of in vivo activity for PD168393 and 174265 against the A431 human epidermoid carcinoma grown as a xenograft in nude mice. PD168393 was far superior to PD 174265 in maintaining suppression of tumor growth with once-daily i.p. dosing. PD168393 produced tumor growth inhibition of 115%, which for this experiment is defined as the median time for treated tumors to reach three volume doublings minus the median time for control tumors to reach three volume doublings, expressed as a percent of treatment duration (15 days). PD 174265, in contrast, produced a tumor growth inhibition of only 13%. The antitumor activity of these two compounds correlated with their ability to suppress the phosphotyrosine content of the EGFr. Both compounds had reduced the phosphorylation status by ≈80%, 4 hr after injection (Fig. 6b). However, by 8 hr, phosphorylation had returned to 75% of controls in mice treated with the reversible compound, PD 174265, and to 100% after 24 hr. In contrast, the phosphotyrosine content of EGFr in animals receiving PD168393 was still reduced by 50% 24 hr after injection. The therapeutic advantage of PD168393 was maintained despite a lower plasma concentration than that of PD 174265 at all time points examined (data not shown).[1]

[1].Proc Natl Acad Sci U S A. 1998 Sep 29; 95(20): 12022–12027.

[2]. Proc Natl Acad Sci U S A. 2006 Jun 27;103(26):9773-8.

[3]. Cell Mol Neurobiol. 2016 Oct;36(7):1169-78.

PD168393 is a member of the class of quinazolines carrying bromoanilino and acrylamido substituents at positions 4 and 6 respectively. It has a role as an epidermal growth factor receptor antagonist. It is a member of quinazolines, a member of acrylamides, a substituted aniline, a member of bromobenzenes and a secondary carboxamide.
PD168393 is an epidermal growth factor receptor inhibitor.
EGFR Inhibitor PD-168393 is a quinazolone compound with anti-tumor activity. PD-168393 is a cell-permeable, irreversible, and selective inhibitor of ligand-dependent epidermal growth factor (EGF) receptor (EGFR). This agent binds to the catalytic domain of EGFR with a 1:1 stoichiometry and inactivates the EGFR tyrosine kinase activity through alkylation of a cystine residue (Cys-773) within the ATP-binding pocket, thereby inhibiting proliferation of EGFR-expressing tumor cells.

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A class of high-affinity inhibitors is disclosed that selectively target and irreversibly inactivate the epidermal growth factor receptor tyrosine kinase through specific, covalent modification of a cysteine residue present in the ATP binding pocket. A series of experiments employing MS, molecular modeling, site-directed mutagenesis, and 14C-labeling studies in viable cells unequivocally demonstrate that these compounds selectively bind to the catalytic domain of the epidermal growth factor receptor with a 1:1 stoichiometry and alkylate Cys-773. While the compounds are essentially nonreactive in solution, they are subject to rapid nucleophilic attack by this particular amino acid when bound in the ATP pocket. The molecular orientation and positioning of the acrylamide group in these inhibitors in relation to Cys-773 entirely support these results as determined from docking experiments in a homology-built molecular model of the ATP site. Evidence is also presented to indicate that the compounds interact in an analogous fashion with erbB2 but have no activity against the other receptor tyrosine kinases or intracellular tyrosine kinases that were tested in this study. Finally, a direct comparison between 6-acrylamido-4-anilinoquinazoline and an equally potent but reversible analog shows that the irreversible inhibitor PD168393 has far superior in vivo antitumor activity in a human epidermoid carcinoma xenograft model with no overt toxicity at therapeutically active doses. The activity profile for this compound is prototypical of a generation of tyrosine kinase inhibitors with great promise for therapeutic significance in the treatment of proliferative disease.[1]

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Her2/neu (Her2) is a tyrosine kinase belonging to the EGF receptor (EGFR)/ErbB family and is overexpressed in 20-30% of human breast cancers. We sought to characterize Her2 signal transduction pathways further by using MS-based quantitative proteomics. Stably transfected cell lines overexpressing Her2 or empty vector were generated, and the effect of an EGFR and Her2 selective tyrosine kinase inhibitor, PD168393, on these cells was characterized. Quantitative measurements were obtained on 462 proteins by using the SILAC (stable isotope labeling with amino acids in cell culture) method to monitor three conditions simultaneously. Of these proteins, 198 showed a significant increase in tyrosine phosphorylation in Her2-overexpressing cells, and 81 showed a significant decrease in phosphorylation. Treatment of Her2-overexpressing cells with PD168393 showed rapid reversibility of the majority of the Her2-triggered phosphorylation events. Phosphoproteins that were identified included many known Her2 signaling molecules as well as known EGFR signaling proteins that had not been previously linked to Her2, such as Stat1, Dok1, and delta-catenin. Importantly, several previously uncharacterized Her2 signaling proteins were identified, including Axl tyrosine kinase, the adaptor protein Fyb, and the calcium-binding protein Pdcd-6/Alg-2. We also identified a phosphorylation site in Her2, Y877, which is located in the activation loop of the kinase domain, is distinct from the known C-terminal tail autophosphorylation sites, and may have important implications for regulation of Her2 signaling. Network modeling, which combined phosphoproteomic results with literature-curated protein-protein interaction data, was used to suggest roles for some of the previously unidentified Her2 signaling proteins.[2]

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Preventing demyelination and promoting remyelination of denuded axons are promising therapeutic strategies for spinal cord injury (SCI). Epidermal growth factor receptor (EGFR) inhibition was reported to benefit the neural functional recovery and the axon regeneration after SCI. However, its role in de- and remyelination of axons in injured spinal cord is unclear. In the present study, we evaluated the effects of EGFR inhibitor, PD168393 (PD), on the myelination in mouse contusive SCI model. We found that expression of myelin basic protein (MBP) in the injured spinal cords of PD treated mice was remarkably elevated. The density of glial precursor cells and oligodendrocytes (OLs) was increased and the cell apoptosis in lesions was attenuated after PD168393 treatment. Moreover, PD168393 treatment reduced both the numbers of OX42 + microglial cells and glial fibrillary acidic protein + astrocytes in damaged area of spinal cords. We thus conclude that the therapeutic effects of EGFR inhibition after SCI involves facilitating remyelination of the injured spinal cord, increasing of oligodendrocyte precursor cells and OLs, as well as suppressing the activation of astrocytes and microglia/macrophages.[3]

C17H13BRN4O

369.22

368.027

C, 55.30; H, 3.55; Br, 21.64; N, 15.17; O, 4.33

194423-15-9

4708

Light yellow to khaki solid powder

1.6±0.1 g/cm3

571.1±50.0 °C at 760 mmHg

279℃

299.2±30.1 °C

0.0±1.6 mmHg at 25°C

1.744

3.72

2

4

4

23

433

0

BrC1=C([H])C([H])=C([H])C(=C1[H])N([H])C1C2C([H])=C(C([H])=C([H])C=2N=C([H])N=1)N([H])C(C([H])=C([H])[H])=O

HTUBKQUPEREOGA-UHFFFAOYSA-N

InChI=1S/C17H13BrN4O/c1-2-16(23)21-13-6-7-15-14(9-13)17(20-10-19-15)22-12-5-3-4-11(18)8-12/h2-10H,1H2,(H,21,23)(H,19,20,22)

N-[4-(3-bromoanilino)quinazolin-6-yl]prop-2-enamide

PD 168393; PD-168393; 4-[(3-Bromophenyl)amino]-6-acrylamidoquinazoline; pd 168393; N-(4-((3-bromophenyl)amino)quinazolin-6-yl)acrylamide; n-{4-[(3-bromophenyl)amino]quinazolin-6-yl}prop-2-enamide; N-[4-(3-bromoanilino)quinazolin-6-yl]prop-2-enamide; PD168393

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)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.77 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: 30% PEG400+0.5% Tween80+5% propylene glycol: 30mg/mL

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 (Please use freshly prepared in vivo formulations for optimal results.)