LE135 is a potent RAR antagonist that selectively binds RARα (Ki of 1.4 μM) and RARβ (Ki of 220 nM), with higher affinity for RARβ. LE135 is selective for RARγ, RXRα, RXRβ and RXRγ. LE135 is also a potent activator of TRPV1 and TRPA1 receptors with EC50 of 2.5 μM and 20 μM, respectively.

Physicochemical Properties

Molecular Formula	C29H30N2O2
Molecular Weight	438.57
Exact Mass	438.23
CAS #	155877-83-1
PubChem CID	10410894
Appearance	Yellow to brown solid powder
Density	1.2±0.1 g/cm3
Boiling Point	601.3±55.0 °C at 760 mmHg
Flash Point	317.5±31.5 °C
Vapour Pressure	0.0±1.8 mmHg at 25°C
Index of Refraction	1.628
LogP	7.36
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	2
Heavy Atom Count	33
Complexity	779
Defined Atom Stereocenter Count	0
InChi Key	YZZAIQOVMHVWBS-UHFFFAOYSA-N
InChi Code	InChI=1S/C29H30N2O2/c1-28(2)14-15-29(3,4)22-17-25-23(16-21(22)28)30-26(18-10-12-19(13-11-18)27(32)33)20-8-6-7-9-24(20)31(25)5/h6-13,16-17H,14-15H2,1-5H3,(H,32,33)
Chemical Name	4-(5,7,7,10,10-pentamethyl-8,9-dihydronaphtho[2,3-b][1,4]benzodiazepin-13-yl)benzoic acid
Synonyms	LE-135; LE 135; LE135
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

ln Vitro	LE135 suppresses the differentiation of human promyelocytic leukemia cells HL-60 caused by Am80 with an IC50 of 150 nM[1]. On several RA response elements, LE135 blocks retinoic acid (RA)-induced transactivation of RARβ but not that of RARα, RARγ, or retinoid X receptor α (RXRα). LE135 significantly suppresses 12-O-tetradecanoylphorbol-13-acetate-induced AP-1 activity when RARβ and RXRα are present [3].
ln Vivo	LE135 produces thermal hyperalgesia and nociceptive responses mostly through TRPV1 channels; however, mechanical allodynia cannot be produced without TRPA1 and TRPV1 channels. In both wild-type and Trpa1−/− mice, an intraplantar injection of LE135 (30 nmol/10 μL) results in mechanical hypersensitivity [2].
References	[1]. Regulation of retinoidal actions by diazepinylbenzoic acids. Retinoid synergists which activate the RXR-RAR heterodimers. J Med Chem. 1997 Dec 19;40(26):4222-34. [2]. LE135, a retinoid acid receptor antagonist, produces pain through direct activation of TRP channels. Br J Pharmacol. 2014 Mar;171(6):1510-20. [3]. Identification of a novel class of retinoic acid receptor beta-selective retinoid antagonists and their inhibitory effects on AP-1 activity and retinoic acid-induced apoptosis in human breast cancer cells. J Biol Chem. 1999 May 28;274(22):15360-6.
Additional Infomation	4-(5,7,7,10,10-pentamethyl-8,9-dihydronaphtho[2,3-b][1,4]benzodiazepin-13-yl)benzoic acid is a dibenzodiazepine.

Solubility Data

Solubility (In Vitro)

DMSO : ~50 mg/mL (~114.01 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.70 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: 2.5 mg/mL (5.70 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication. 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 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.2801 mL	11.4007 mL	22.8014 mL
	5 mM	0.4560 mL	2.2801 mL	4.5603 mL
	10 mM	0.2280 mL	1.1401 mL	2.2801 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.