DAPT is a γ-secretase inhibitor, reduces the total beta-amyloid peptide (Aβ) production with IC₅₀ of 20 nM in HEK 293 cells.

IC50: 20 nM (Aβ, in HEK 293 cells)^[1]

DAPT inhibits Aβ production over 90%, effects only a modest reduction in APPβ in the culture media. Although APPβ is reduced by about 30% by DAPT treatment, this effect is not concentration-dependent and is reversed by the removal of DAPT^[1]. CNE-2 cells are treated with increasing concentrations of DAPT (0, 25, 50 and 75 μM), and the γ-secretase-generated Notch 1 fragment Val1744-NICD is decreased after 48 h in a dose-dependent manner (P<0.01). the="" activation="" of="" γ-secretase="" is="" almost="" completely="" inhibited="" by="" dapt="" at="" the="" concentration="" of="" 50="">^[2].

DAPT is administered to PDAPP mice (100 mg/kg s.c.) and the levels of DAPT and Aβ are examined in the brain cortex. Peak DAPT levels of 490 ng/g are achieved in the brain 3 h after treatment, and levels greater than 100 ng/g (~200 nM) are sustained throughout the first 18 h. These brain concentrations of DAPT are in excess of its IC₅₀ for lowering Aβ in neuronal cultures (115 nM), and results in a robust and sustains pharmacodynamic effect^[1]. DAPT protects brain against cerebral ischemia by down-regulating the expression of Notch 1 and Nuclear factor kappa B in rats. Western blot analyses also show a significant decrease of Notch 1 and NF-κB expression in DAPT (0.03 mg/kg) group (P<0.05 vs.="" mcao="">^[3].

• [1]. Dovey HF, et al. Functional gamma-secretase inhibitors reduce beta-amyloid peptide levels in brain. J Neurochem. 2001 Jan;76(1):173-81.

  [2]. Zhou JX, et al. γ-secretase inhibition combined with cisplatin enhances apoptosis of nasopharyngeal carcinoma cells.Exp Ther Med. 2012 Feb;3(2):357-361.

  [3]. Li S, et al. DAPT protects brain against cerebral ischemia by down-regulating the expression of Notch 1 and nuclear factor κB in rats. Neurol Sci. 2012 Dec;33(6):1257-64.

  [4]. Tanimizu N, et al. Intrahepatic bile ducts are developed through formation of homogeneous continuous luminal network and its dynamic rearrangement in mice. Hepatology. 2016 Jul;64(1):175-88.

  [5]. Michael T. Chang, et al. Notch Drives Proliferation And Radiation Resistance Of Cancer Stem Cells In Adenoid Cystic Carcinoma. Yale University. January 2016.

DAPT is dissolved in DMSO and stored, and then diluted with appropriate media (DMSO 0.1%) before use^[1].

Human embryonic kidney cells, transfected with the gene for APP₇₅₁ (HEK 293) are used for routine Aβ reduction assays. Cells are plated in 96-well plates and allowed to adhere overnight in Dulbecco"s modified Eagle medium (DMEM) supplemented with 10% heat-inactivated fetal bovine serum. Cells are pre-treated for 2 h at 37°C with DAPT (0, 0.4, 2, 10, 50 and 250 nM), media are aspirated off and fresh compound solutions applied. After an additional 2-h treatment period, conditioned media are drawn off and analyzed by a sandwich ELISA (266-3D6) specific for total Aβ. Reduction of Aβ production is measured relative to control cells treated with 0.1% DMSO and expressed as a percentage inhibition. Data from at least six doses in duplicate are fitted to a four-parameter logistical model using XLfit software in order to determine potency^[1]. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

DAPT is formulated in corn oil, 5% (v/v) ethanol (Mice)^[1].
DAPT is dissolved in 0.01 M PBS including 5% DMSO to prepare concentrations of 8.3 mg/mL (Rat)^[3].

Mice^[1]
The three- to four-month-old heterozygous PDAPP transgenic mice overexpressing the APP_V717F mutant form of the amyloid precursor protein. Each treatment group (n=10) consists of equal numbers of age-matched male and female animals that are fasted overnight prior to treatment. Both treatment and control groups are dosed at a volume of 10 mL/kg with DAPT or vehicle alone. Tissues are processed and all Aβ and APP measurements are made. After removal of the brain, the cortex from one hemisphere is homogenized, extracted with 5 M guanidine, 50 mM Tris-pH 8.0, centrifuged, and the supernatant is used for Aβ measurements. Cortex from the other hemisphere is snap frozen for analysis of compound levels. Aβ levels are expressed as ng/g of wet tissue weight, and percentage reductions are calculated relative to the mean Aβ level of tissue from vehicle-treated control animals. Data are analyzed with Mann-Whitney non-parametric statistics to assess significance.
Rat^[3]
Male Sprague-Dawley rats (260-290 g) are used. DAPT solution is stereotactically injected into the lateral cerebral ventricle (LV) immediately after MCAO. The stereotactic injections into the LVs are performed at coordinates −0.8 mm anteroposterior, ±1.5 mm mediolateral and −4.5 mm dorsoventral from the bregma. 30 rats are randomly assigned to three operating groups (10 rats in each group): sham-operated group that receive equal volume of PBS without MCAO operation; MCAO group that receive equal volume PBS after MCAO (MCAO); and DAPT group that receive DAPT as 0.03 mg/kg after MCAO. 24 h after operation the first neurological function is assessed and then 48 h after operation the second neurological function is assessed. Meanwhile, brain water content and infarction volume are measured and compared among different groups. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

• [1]. Dovey HF, et al. Functional gamma-secretase inhibitors reduce beta-amyloid peptide levels in brain. J Neurochem. 2001 Jan;76(1):173-81.

  [2]. Zhou JX, et al. γ-secretase inhibition combined with cisplatin enhances apoptosis of nasopharyngeal carcinoma cells.Exp Ther Med. 2012 Feb;3(2):357-361.

  [3]. Li S, et al. DAPT protects brain against cerebral ischemia by down-regulating the expression of Notch 1 and nuclear factor κB in rats. Neurol Sci. 2012 Dec;33(6):1257-64.

  [4]. Tanimizu N, et al. Intrahepatic bile ducts are developed through formation of homogeneous continuous luminal network and its dynamic rearrangement in mice. Hepatology. 2016 Jul;64(1):175-88.

  [5]. Michael T. Chang, et al. Notch Drives Proliferation And Radiation Resistance Of Cancer Stem Cells In Adenoid Cystic Carcinoma. Yale University. January 2016.

432.46

C₂₃H₂₆F₂N₂O₄

208255-80-5

Room temperature in continental US; may vary elsewhere

DMSO: ≥ 215 mg/mL

DAPT is mixed with olive oil^[4]. DAPT is prepared in corn oil^[5].

* "<1 mg/ml"="" means="" slightly="" soluble="" or="" insoluble.="" "≥"="" means="" soluble,="" but="" saturation="">

• [1]. Dovey HF, et al. Functional gamma-secretase inhibitors reduce beta-amyloid peptide levels in brain. J Neurochem. 2001 Jan;76(1):173-81.

  [2]. Zhou JX, et al. γ-secretase inhibition combined with cisplatin enhances apoptosis of nasopharyngeal carcinoma cells.Exp Ther Med. 2012 Feb;3(2):357-361.

  [3]. Li S, et al. DAPT protects brain against cerebral ischemia by down-regulating the expression of Notch 1 and nuclear factor κB in rats. Neurol Sci. 2012 Dec;33(6):1257-64.

  [4]. Tanimizu N, et al. Intrahepatic bile ducts are developed through formation of homogeneous continuous luminal network and its dynamic rearrangement in mice. Hepatology. 2016 Jul;64(1):175-88.

  [5]. Michael T. Chang, et al. Notch Drives Proliferation And Radiation Resistance Of Cancer Stem Cells In Adenoid Cystic Carcinoma. Yale University. January 2016.