1404508-99-1Relevant articles and documents
Exploring the PROTAC degron candidates: OBHSA with different side chains as novel selective estrogen receptor degraders (SERDs)
Li, Yuanyuan,Zhang, Silong,Zhang, Jing,Hu, Zhiye,Xiao, Yuan,Huang, Jian,Dong, Chune,Huang, Shengtang,Zhou, Hai-Bing
, p. 48 - 61 (2019)
As the mutant estrogen receptor (ER) continues to be characterized, breast cancer is becoming increasingly difficult to cure when treated with hormone therapy. In this regard, a strategy to selectively and effectively degrade the ER might be an effective alternative to endocrine therapy for breast cancer. In a previous study, we identified a novel series of 7-oxabicyclo[2.2.1]heptene sulfonamide (OBHSA) compounds as full ER antagonists while lacking the prototypical ligand side chain that has been widely used to induce antagonism of ERα. Further crystal structure studies and phenotypic assays revealed that these compounds are selective estrogen receptor degraders (SERDs) with a new mechanism of action. However, from a drug discovery point of view, there still is room to improve the potency of these OBHSA compounds. In this study, we have developed new classes of SERDs that contain the OBHSA core structure and different side chains, e.g., basic side chains, long alkyl acid side chains, and glycerol ether side chains, to simply mimic the degrons of proteolysis targeting chimera (PROTAC) and then investigated the structure-activity relationships of these PROTAC-like hybrid compounds. These novel SERDs could effectively inhibit MCF-7 cell proliferation and demonstrated good ERα degradation efficacy. Among the SERDs, compounds 17d, 17e and 17g containing a basic side chain with a N-trifluoroethyl substituent and a para methoxyl group at the phenyl group of the sulfonamide turned out to be the best candidates for ER degraders. A further docking study of these compounds with ERα elucidates their structure-activity relationships, which provides guidance to design new PROTAC degrons targeting ER for breast cancer therapy. Lastly, easy modification of these PROTAC-like SERDs enables further fine-tuning of their pharmacokinetic properties, including oral availability.
Bicyclic core estrogens as full antagonists: Synthesis, biological evaluation and structure-activity relationships of estrogen receptor ligands based on bridged oxabicyclic core arylsulfonamides
Zhu, Manghong,Zhang, Chen,Nwachukwu, Jerome C.,Srinivasan, Sathish,Cavett, Valerie,Zheng, Yangfan,Carlson, Kathryn E.,Dong, Chune,Katzenellenbogen, John A.,Nettles, Kendall W.,Zhou, Hai-Bing
, p. 8692 - 8700 (2013/01/15)
Compounds that block estrogen action through the estrogen receptor (ER) or downregulate ER levels are useful for the treatment of breast cancer and endocrine disorders. In our search for structurally novel estrogens having three-dimensional core scaffolds, we found some compounds with a 7-oxabicyclo[2.2.1]heptene core that bound well to the ERs. The best of these compounds, a phenyl sulfonate ester (termed OBHS for oxabicycloheptene sulfonate), was a partial antagonist on both ERα and ERβ. Although OBHS bears no structural resemblance to other estrogen antagonists, it appears to achieve its partial antagonist character by stabilizing a novel conformation of the ER that involves a significant distortion of helix-11. To enhance the antagonist properties of these oxabicyclo[2.2.1]heptane core ligands, we expanded the functional diversity of OBHS by replacing the sulfonate with secondary or tertiary sulfonamides (-SO2NR-), isoelectronic and potentially isostructural molecular replacements. An array of 16 OBHS sulfonamide analogues were prepared through a Diels-Alder reaction of a 3,4-diarylfuran using various N-aryl vinyl sulfonamide dienophiles. While the more polar secondary sulphonamides were weak ligands, certain of the tertiary sulfonamides had very good ER binding affinity. In HepG2 cell reporter gene assays, the sulphonamides had moderate potency, but they showed lower intrinsic transcriptional activity on ERα than the selective estrogen receptor modulator (SERM) hydroxytamoxifen or OBHS, and they were inverse agonists on ERβ. Thus, the behaviour of these OBH-sulfonamides more closely mirrors the activity of full antagonists like the drug fulvestrant (ICI 182780), and their greater antagonist biocharacter appears to arise from an accentuated distortion of helix-11.