ME0328 (ME-0328) is a novel, potent and selective inhibitor of Poly (ADP-ribose) polymerase (PARP) with potential anticancer activity. It is approximately seven times more selective than PARP1 (IC50 = 6.3 μM) and inhibits PARP3 with an IC50 of 0.89 μM.

Physicochemical Properties

Molecular Formula	C19H19N3O2
Molecular Weight	321.37
Exact Mass	321.148
Elemental Analysis	C, 71.01; H, 5.96; N, 13.08; O, 9.96
CAS #	1445251-22-8
Related CAS #	1445251-22-8
PubChem CID	135566764
Appearance	White to off-white solid powder
LogP	3.985
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	3
Rotatable Bond Count	5
Heavy Atom Count	24
Complexity	497
Defined Atom Stereocenter Count	1
SMILES	O=C(N[C@H](C1=CC=CC=C1)C)CCC(NC2=C3C=CC=C2)=NC3=O
InChi Key	QIHBWVVVRYYYRO-ZDUSSCGKSA-N
InChi Code	InChI=1S/C19H19N3O2/c1-13(14-7-3-2-4-8-14)20-18(23)12-11-17-21-16-10-6-5-9-15(16)19(24)22-17/h2-10,13H,11-12H2,1H3,(H,20,23)(H,21,22,24)/t13-/m0/s1
Chemical Name	3-(4-oxo-3H-quinazolin-2-yl)-N-[(1S)-1-phenylethyl]propanamide
Synonyms	ME 0328; ME0328; ME-0328
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	ARTD3/PARP3 ( IC50 = 0.89 μM ); ARTD1/PARP1 ( IC50 = 6.3 μM ); ARTD2/PARP2 ( IC50 = 10.8 μM ); ARTD6/TNKS2 ( IC50 = 34.3 μM ); ARTD5/TNKS1 ( IC50 = 47.3 μM ); ARTD10/PARP10 ( IC50 = 71.3 μM )
ln Vitro	In vitro activity: ME0328 is an effective and specific inhibitor of ARTD3/PARP3 that exhibits cellular activity. With an IC50 of 0.89±0.28 μM, ME0328 inhibits the transferase activity of ARTD3 in the in vitro histone H1 modification assay. ME0328 and ME0355 (at 10 μM) in human A549 cells postpone the resolution of foci containing γH2AX, which act as markers for DNA double strand break repair after γ-irradiation (2 Gy). ME0328 has been shown through in silico and in vitro physicochemical and metabolic profiling to be soluble, cell permeable, and metabolically stable in rat hepatocytes and human liver microsomes[1].
ln Vivo	NA
Enzyme Assay	ARTD proteins tagged with hexahistidine and recombinant histone proteins captured on 96-well Ni2+-chelating plates (5-PRIME) are used to measure protein ADP-ribosylation. NAD+ (2% biotinylated) is added to initiate ADP-ribosylation reactions, and chemiluminescence is used to identify the altered reaction products. Plots of starting rates against NAD+ concentrations and linear curve fitting with GraphPad Prism are used to estimate km values. Dimethyl sulfoxide (DMSO) is used to dissolve each compound to a stock concentration of 50 millimolar. In order to find the IC50 values, experiments are carried out using 1% (v/v) DMSO concentration and compound concentrations ranging from 10 nM to 450 μM. For every transferase, measurements are performed at a concentration of NAD+ less than Km. GraphPad Prism is used to fit curves in order to estimate IC50 values. The values that are reported are the means ± standard error of the curve fits obtained from duplicate or triplicate experiments, with each experiment being determined using three replicates.
Cell Assay	MRC5 and A549 cells are used to test compounds for cytotoxicity using WST-1 assays. Dulbecco's Modified Eagle's Medium, enhanced with 10% fetal calf serum (FCS), penicillin, and streptomycin, is used to cultivate A549 cells. Minimal Essential Medium, which is enhanced with 10% FCS, penicillin, streptomycin, and l-glutamine, is used to cultivate MRC5 cells. Both cell lines are kept at 37°C with 5% CO2 in a humidified incubator.
Animal Protocol	NA NA
References	[1]. PARP inhibitor with selectivity toward ADP-ribosyltransferase ARTD3/PARP3. ACS Chem Biol. 2013 Aug 16;8(8):1698-703.

Solubility Data

Solubility (In Vitro)

DMSO: 64~75 mg/mL (199.1~233.4 mM) Water: <1 mg/mL Ethanol: <1 mg/mL

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (7.78 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. Solubility in Formulation 2: 5%DMSO Corn oil: 1.75mg/ml (5.45mM)  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.1117 mL	15.5584 mL	31.1168 mL
	5 mM	0.6223 mL	3.1117 mL	6.2234 mL
	10 mM	0.3112 mL	1.5558 mL	3.1117 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.