Identification of potent pan-ephrin receptor kinase inhibitors using DNA-encoded chemistry technology.

EPH receptors (EPHs), the largest family of tyrosine kinases, phosphorylate downstream substrates upon binding of ephrin cell surface-associated ligands. In a large cohort of endometriotic lesions from individuals with endometriosis, we found that EPHA2 and EPHA4 expressions are increased in endometriotic lesions relative to normal eutopic endometrium. Because signaling through EPHs is associated with increased cell migration and invasion, we hypothesized that chemical inhibition of EPHA2/4 could have therapeutic value. We screened DNA-encoded chemical libraries (DECL) to rapidly identify EPHA2/4 kinase inhibitors. Hit compound, CDD-2693, exhibited picomolar/nanomolar kinase activity against EPHA2 (Ki: 4.0 nM) and EPHA4 (Ki: 0.81 nM). Kinome profiling revealed that CDD-2693 bound to most EPH family and SRC family kinases. Using NanoBRET target engagement assays, CDD-2693 had nanomolar activity versus EPHA2 (IC50: 461 nM) and EPHA4 (IC50: 40 nM) but was a micromolar inhibitor of SRC, YES, and FGR. Chemical optimization produced CDD-3167, having picomolar biochemical activity toward EPHA2 (Ki: 0.13 nM) and EPHA4 (Ki: 0.38 nM) with excellent cell-based potency EPHA2 (IC50: 8.0 nM) and EPHA4 (IC50: 2.3 nM). Moreover, CDD-3167 maintained superior off-target cellular selectivity. In 12Z endometriotic epithelial cells, CDD-2693 and CDD-3167 significantly decreased EFNA5 (ligand) induced phosphorylation of EPHA2/4, decreased 12Z cell viability, and decreased IL-1ß-mediated expression of prostaglandin synthase 2 (PTGS2). CDD-2693 and CDD-3167 decreased expansion of primary endometrial epithelial organoids from patients with endometriosis and decreased Ewing's sarcoma viability. Thus, using DECL, we identified potent pan-EPH inhibitors that show specificity and activity in cellular models of endometriosis and cancer.

Reversible male contraception by targeted inhibition of serine/threonine kinase 33.

Men or mice with homozygous serine/threonine kinase 33 (STK33) mutations are sterile owing to defective sperm morphology and motility. To chemically evaluate STK33 for male contraception with STK33-specific inhibitors, we screened our multibillion-compound collection of DNA-encoded chemical libraries, uncovered potent STK33-specific inhibitors, determined the STK33 kinase domain structure bound with a truncated hit CDD-2211, and generated an optimized hit CDD-2807 that demonstrates nanomolar cellular potency (half-maximal inhibitory concentration = 9.2 nanomolar) and favorable metabolic stability. In mice, CDD-2807 exhibited no toxicity, efficiently crossed the blood-testis barrier, did not accumulate in brain, and induced a reversible contraceptive effect that phenocopied genetic STK33 perturbations without altering testis size. Thus, STK33 is a chemically validated, nonhormonal contraceptive target, and CDD-2807 is an effective tool compound.

Discovery of Highly Potent and BMPR2-Selective Kinase Inhibitors Using DNA-Encoded Chemical Library Screening.

The discovery of monokinase-selective inhibitors for patients is challenging because the 500+ kinases encoded by the human genome share highly conserved catalytic domains. Until now, no selective inhibitors unique for a single transforming growth factor ß (TGFß) family transmembrane receptor kinase, including bone morphogenetic protein receptor type 2 (BMPR2), have been reported. This dearth of receptor-specific kinase inhibitors hinders therapeutic options for skeletal defects and cancer as a result of an overactivated BMP signaling pathway. By screening 4.17 billion "unbiased" and "kinase-biased" DNA-encoded chemical library molecules, we identified hits CDD-1115 and CDD-1431, respectively, that were low-nanomolar selective kinase inhibitors of BMPR2. Structure-activity relationship studies addressed metabolic lability and high-molecular-weight issues, resulting in potent and BMPR2-selective inhibitor analogs CDD-1281 (IC50 = 1.2 nM) and CDD-1653 (IC50 = 2.8 nM), respectively. Our work demonstrates that DNA-encoded chemistry technology (DEC-Tec) is reliable for identifying novel first-in-class, highly potent, and selective kinase inhibitors.

Cycloartane- and Lanostane-Type Triterpenoids from the Resin of Parthenium argentatum AZ-2, a Byproduct of Guayule Rubber Production.

A total of 12 new cycloartane- and lanostane-type triterpenoids including 16-deoxyargentatin A (1), 16-deoxyisoargentatin A (2), 7-oxoisoargentatin A (3), 24-epi-argentatin H (4), 24-O-p-anisoylargentatin C (5), 24-O-trans-cinnamoylargentatin C (6), 16-dehydroargentatin C (7), 16,17(20)-didehydroargentatin C (8), isoargentatin C (9), isoargentatin H (10), 3-epi-quisquagenin (11), and isoquisquagenin (12) together with 10 known triterpenoids (13-22) were isolated from the resin of Parthenium argentatum AZ-2 obtained as a byproduct of Bridgestone guayule rubber production. The structures of new triterpenoids 1-12 and argentatin H (13), which has previously been characterized as its diacetate (23), were elucidated by extensive analysis of their spectroscopic data and chemical conversions, and the known compounds 14-22 were identified by comparison of their spectroscopic data with those reported. Of these, 13, 14, and 18 exhibited weak cytotoxic activity for several cancer cell lines.

Synthesis and biological evaluation of some novel 1,2,3-triazole hybrids of myrrhanone B isolated from Commiphora mukul gum resin: Identification of potent antiproliferative leads active against prostate cancer cells (PC-3).

A series of 28 novel 1,2,3-triazole hybrids of myrrhanone B have been designed and synthesized by employing regioselective Cu catalyzed Huisgen 1,3-dipolar cycloaddition reaction in highly efficient manner. All the synthesized analogues were assessed for their antiproliferative potential against A549 (Lung), DU145 (Prostate), MDA-MB-231 (Breast), SiHa (Cervical), U87MG (Glioblastoma), PC-3 (Prostate), HT-29 (Colon), L132 (Normal lung) cell lines. Further, the synthesized hybrids have also been screened for anti-inflammatory activity (TNF-α and IL-1ß) and α-glucosidase inhibitory activity. The biological results revealed that compound 11 (meta hydroxy phenyl 1,2,3-triazole) and compound 29 (deoxyuridine 1,2,3-triazole) found to be the most potent antiproliferative ones against PC-3 cell line. Compound 11 (IC50: 6.57 ± 0.62 µM) showed six folds more potent than parent compound 1 (IC50: 40.67 ± 2.2 µM) and displayed almost identical inhibitory activity with standard doxorubicin (IC50: 5.05 ± 0.25 µM), whereas compound 29 (IC50: 10.85 ± 0.90 µM) exhibited four folds more potent than parent myrrhanone B (1). In view of potent activity of compounds 11 and 29 they have been subjected to detailed flowcytometry analysis. Compound 29 treated cells significantly increased the SubG1 population of cells indicative of apoptosis compared to compound 11. Further, the results of anti-inflammatory studies indicated that compounds 3, 6, 9, 27, 28, 29 and 30 exhibited significant inhibitory activity against both TNF-α and IL-1ß than the parent compound 1. Interestingly, compound 27 exhibited good activity towards inflammatory cytokines TNF-α (IC50: 7.83 ± 0.95 µM). Interestingly, α-glucosidase inhibitory assay results revealed that compounds 14 (IC50: 2.77 ± 0.59 µM) and 16 (IC50: 4.12 ± 0.77 µM) as the most potent ones. In fact, compound 14 exhibited highest activity and found to be several times more potent than the parent compound 1 as well as standard acarbose (IC50: 2124 ± 170 µM).