Letrozole

• CAT Number: A001090
• CAS Number: 112809-51-5
• Molecular Formula: C17H11N5
• Molecular Weight: 285.3
• Purity: ≥95%
• Synonyms: CGS 20267
• Target: Aromatase
• Solubility: >14.3mg/mL in DMSO
• Storage: 3 years -20C powder
• IUPAC Name: 4-[(4-cyanophenyl)-(1,2,4-triazol-1-yl)methyl]benzonitrile
• InChI: InChI=1S/C17H11N5/c18-9-13-1-5-15(6-2-13)17(22-12-20-11-21-22)16-7-3-14(10-19)4-8-16/h1-8,11-12,17H
• InChIKey: HPJKCIUCZWXJDR-UHFFFAOYSA-N
• SMILES: C1=CC(=CC=C1C#N)C(C2=CC=C(C=C2)C#N)N3C=NC=N3

Letrozole (CAS 112809-51-5), also known as CGS-20267, is a nonsteroidal inhibitor of estrogen synthesis with antineoplastic activity. As a third-generation aromatase inhibitor, letrozole selectively and reversibly inhibits aromatase, which may result in growth inhibition of estrogen-dependent breast cancer cells. Aromatase, a cytochrome P-450 enzyme localized to the endoplasmic reticulum of the cell and found in many tissues including those of the premenopausal ovary, liver, and breast, catalyzes the aromatization of androstenedione and testosterone into estrone and estradiol, the final step in estrogen biosynthesis.

Reference

1:Erratum: Combined letrozole and clomiphene versus letrozole and clomiphene alone in infertile patients with polycystic ovary syndrome [Erratum]. [No authors listed]Drug Des Devel Ther. 2017 Apr 28;11:1367. doi: 10.2147/DDDT.S134671. eCollection 2017. PMID: 28496306 Free PMC Article
2:Comparison of palbociclib in combination with letrozole or fulvestrant with endocrine therapies for advanced/metastatic breast cancer: network meta-analysis. Chirila C, Mitra D, Colosia A, Ling C, Odom D, Iyer S, Kaye JA.Curr Med Res Opin. 2017 May 16:1-10. doi: 10.1080/03007995.2017.1325730. [Epub ahead of print] PMID: 28463012
3:Letrozole+ GnRH antagonist stimulation protocol in poor ovarian responders undergoing intracytoplasmic sperm injection cycles: An RCT. Ebrahimi M, Akbari-Asbagh F, Ghalandar-Attar M.Int J Reprod Biomed (Yazd). 2017 Feb;15(2):101-108. PMID: 28462402 Free PMC Article
4:Can letrozole plus HMG protocol improve pregnancy outcomes in frozen-thawed embryo transfer? An RCT. Aleyasin A, Aghahosseini M, Safdarian L, Noorzadeh M, Fallahi P, Rezaeian Z, Hoseinimosa S.Int J Reprod Biomed (Yazd). 2017 Feb;15(2):83-86. PMID: 28462399 Free PMC Article
5:Effect of combination of Withania somnifera Dunal and Tribulus terrestris Linn on letrozole induced polycystic ovarian syndrome in rats. Saiyed A, Jahan N, Makbul SAA, Ansari M, Bano H, Habib SH.Integr Med Res. 2016 Dec;5(4):293-300. doi: 10.1016/j.imr.2016.10.002. Epub 2016 Oct 19. PMID: 28462131 Free PMC Article
6:Phase 2 trial of everolimus and letrozole in relapsed estrogen receptor-positive high-grade ovarian cancers. Colon-Otero G, Weroha SJ, Foster NR, Haluska P, Hou X, Wahner-Hendrickson AE, Jatoi A, Block MS, Dinh TA, Robertson MW, Copland JA.Gynecol Oncol. 2017 Apr 28. pii: S0090-8258(17)30801-6. doi: 10.1016/j.ygyno.2017.04.020. [Epub ahead of print] PMID: 28461031
7:Pregnancy and neonatal outcomes following letrozole use in frozen-thawed single embryo transfer cycles. Tatsumi T, Jwa SC, Kuwahara A, Irahara M, Kubota T, Saito H.Hum Reprod. 2017 Jun 1;32(6):1244-1248. doi: 10.1093/humrep/dex066. PMID: 28398491
8:The effects of Nobiletin, Hesperetin, and Letrozole in a combination on the activity and expression of aromatase in breast cancer cells. Rahideh ST, Keramatipour M, Nourbakhsh M, Koohdani F, Hoseini M, Shidfar F.Cell Mol Biol (Noisy-le-grand). 2017 Feb 28;63(2):9-13. doi: 10.14715/cmb/2017.63.2.2. PMID: 28364779
9:Comparing the Administration of Letrozole and Megestrol Acetate in the Treatment of Women with Simple Endometrial Hyperplasia without Atypia: A Randomized Clinical Trial. Moradan S, Nikkhah N, Mirmohammadkhanai M.Adv Ther. 2017 May;34(5):1211-1220. doi: 10.1007/s12325-017-0509-8. Epub 2017 Mar 28. PMID: 28353144
10:Exercise differentially affects metabolic functions and white adipose tissue in female letrozole- and dihydrotestosterone-induced mouse models of polycystic ovary syndrome. Marcondes RR, Maliqueo M, Fornes R, Benrick A, Hu M, Ivarsson N, Carlström M, Cushman SW, Stenkula KG, Maciel GAR, Stener-Victorin E.Mol Cell Endocrinol. 2017 Jun 15;448:66-76. doi: 10.1016/j.mce.2017.03.025. Epub 2017 Mar 24. PMID: 28344042