Identification of Novel ROS Inducers: Quinone Derivatives Tethered to Long Hydrocarbon Chains

We performed the first synthesis of the 17-carbon chain-tethered quinone moiety <b>22</b> (SAN5201) of irisferin A, a natural product exhibiting anticancer activity, and its derivatives. We found that <b>22</b> is a potent ROS inducer and cytotoxic agent. Compound <b>25</b> (SAN7401), the hydroquinone form of <b>22</b>, induced a significant release of intracellular ROS and apoptosis (EC₅₀ = 1.3–2.6 μM) in cancer cell lines, including A549 and HCT-116. Compared with the activity of a well-known ROS inducer, piperlongumine, <b>22</b> and <b>25</b> showed stronger cytotoxicity and higher selectivity over noncancerous cells. Another hydroquinone tethering 12-carbon chain, <b>26</b> (SAN4601), generated reduced levels of ROS but showed more potent cytotoxicity (EC₅₀ = 0.8–1.6 μM) in cancer cells, although it lacked selectivity over noncancerous cells, implying that the naturally occurring 17-carbon chain is also crucial for ROS production and a selective anticancer effect. Both <b>25</b> and <b>26</b> displayed strong, equipotent activities against vemurafenib-resistant SK-Mel2 melanoma cells and p53-deficient H1299 lung cancer cells as well, demonstrating their broad therapeutic potential as anticancer agents

A Pyrazolo[3,4‑<i>d</i>]pyrimidin-4-amine Derivative Containing an Isoxazole Moiety Is a Selective and Potent Inhibitor of RET Gatekeeper Mutants

Aberrant RET kinase signaling plays critical roles in several human cancers such as thyroid carcinoma. The gatekeeper mutants (V804L or V804M) of RET are resistant to currently approved RET inhibitors such as cabozantinib and vandetanib. We, for the first time, report a highly selective and extremely potent RET inhibitor, <b>6i</b> rationally designed. Compound <b>6i</b> inhibits strongly RET gatekeeper mutants and other clinically relevant RET mutants as well as wt-RET. This substance also significantly suppresses growth of thyroid cancer-derived TT cell lines and Ba/F3 cells transformed with various RET mutants. Docking studies reveal that the isoxazole moiety in <b>6i</b> is responsible for binding affinity improvement by providing additional site for H-bonding with Lys758. Also, <b>6i</b> not only substantially blocks cellular RET autophosphorylation and its downstream pathway, it markedly induces apoptosis and anchorage-independent growth inhibition in TT cell lines while having no effect on normal thyroid Nthy ori-3-1 cells

Development of Highly Potent and Selective Steroidal Inhibitors and Degraders of CDK8

Cortistatin A is a natural product isolated from the marine sponge Corticium simplex and was found to be a potent and selective inhibitor of CDK8. Many synthetic groups have reported total syntheses of Cortistatin A; however, these syntheses require between 16 and 30 steps and report between 0.012–2% overall yields, which is not amenable to large-scale production. Owing to similarities between the complex core of Cortistatin A and the simple steroid core, we initiated a campaign to design simple, more easily prepared CDK8 inhibitors based on a steroid scaffold that would be more convenient for large-scale synthesis. Herein, we report the discovery and optimization of JH-VIII-49, a potent and selective inhibitor of CDK8 with a simple steroid core that has an eight-step synthesis with a 33% overall yield, making it suitable for large-scale preparation. Using this scaffold, we then developed a bivalent small molecule degrader, JH-XI-10-02, that can recruit the E3 ligase CRL4^Cereblon to promote the ubiquitination and proteosomal degradation of CDK8

Discovery of a broad spectrum antiproliferative agent with selectivity for DDR1 kinase: cell line-based assay, kinase panel, molecular docking, and toxicity studies

<div><p></p><p>Herein, we report compound <b>KST9046</b>, a new agent possessing quinazoline-urea scaffold. Preliminary biological evaluation done by the National Cancer Institute (NCI), USA, showed a great inhibitory effect of <b>KST9046</b> over the 60 cell-line tumor panel. Accordingly, it was selected for a dose-response assay; a broad spectrum antiproliferative activity with GI₅₀ ranging from 1.3 to 3.9 µM was exerted. To explore a potential kinase inhibitory effect, <b>KST9046</b> was applied at a single dose of 10 µM against a kinase panel of 347 different enzymes representing >50% of the predicted human protein kinome. Interestingly, selective inhibition of 76% was observed on DDR1 kinase. Further, <b>KST9046</b> showed an IC₅₀ value of 4.38 µM for DDR1. A molecular docking model presented <b>KST9046</b> as a potential type III inhibitor for DDR1 kinase with an allosteric mode of interaction, which may offer an explanation for its selectivity. As further investigation, CYP450 assay was carried out for <b>KST9046</b>, it showed a promising toxicity profile against four different isoforms. Based on these findings, <b>KST9046</b> can be further evaluated as a promising safe new hit for the development of broad spectrum anticancer agents with a selectivity for DDR1 kinase.</p></div

Discovery of a Highly Potent and Selective Indenoindolone Type 1 Pan-FLT3 Inhibitor

For a subpopulation of acute myeloid leukemia (AML) patients, the mutationally activated tyrosine kinase FLT3, has emerged as a promising target for therapy. The development of drug resistance due to mutation is a growing concern for mutant FLT3 inhibitors, such as PKC412, Quizartinib, PLX3397, and Crenolanib. Thus, there is a need to develop novel FLT3 inhibitors that overcome these mutations. Here we report the development of a novel type I ATP competitive inhibitor, JH-IX-179, that is extremely potent and selective for FLT3. JH-IX-179 also has the highest affinity for three constitutively active isoforms of FLT3 (FLT3-ITD, FLT3-N841I, and FLT3-D835V) compared to a panel 456 other kinases. The unique and specific kinase inhibition profile suggests that this chemotype may represent an attractive starting point for the development of further improved FLT3 inhibitors with therapeutic potential in tumors harboring deregulated FLT3 activity

Discovery of a benzo[e]pyrimido-[5,4-b][1,4]diazepin-6(11H)-one as a Potent and Selective Inhibitor of Big MAP Kinase 1

Kinome-wide selectivity profiling of a collection of 2-amino-pyrido[2,3-d]pyrimidines followed by cellular structure−activity relationship-guided optimization resulted in the identification of moderately potent and selective inhibitors of BMK1/ERK5 exemplified by <b>11</b>, <b>18</b>, and <b>21</b>. For example, <b>11</b> possesses a dissociation constant (<i>K</i>_d) for BMK1 of 19 nM, a cellular IC₅₀ for inhibiting epidermal growth factor induced BMK1 autophosphorylation of 0.19 ± 0.04 μM, and an Ambit KINOME<i>scan</i> selectivity score (<i>S</i>₅) of 0.035. Inhibitors <b>18</b> and <b>21</b> are also potent BMK1 inhibitors and possess favorable pharmacokinetic properties which enable their use as pharmacological probes of BMK1-dependent phenomena as well as starting points for further optimization efforts

Image_1_A novel NLRP3 inhibitor as a therapeutic agent against monosodium urate-induced gout.jpeg

BackgroundSince NEK7 is critical for NLRP3 inflammasome activation, NEK7 inhibitors could be employed as therapeutic agents against gout, a representative disease caused by NLRP3 inflammasome.MethodsWe designed NEK7 inhibitors based on biochemical kinome profiling of 2,7-substituted thieno[3,2-d]pyrimidine derivatives (SLC3031~3035 and SLC3037). Inflammasome activation was assessed by ELISA of IL-1b and immunoblotting of IL-1b maturation after treatment of bone marrow-derived macrophages with LPS+monosodium urate (MSU). NLPR3 binding to NEK7 and oligomerization were examined using immunoprecipitation and Blue Native gel electrophoresis, respectively. In vivo effect was investigated by studying gross and histopathological changes of food pad tissue of MSU-injected mice, together with assays of maturation of IL-1b and ASC speck in the tissue.ResultsSLC3037 inhibited inflammasome by MSU and other inflammasome activators through blockade of NLRP3 binding to NEK7 or oligomerization, and subsequent ASC oligomerization/phosphorylation. SLC3037 significantly reduced foot pad thickness and inflammation by MSU, which was superior to the effects of colchicine. SLC3037 significantly reduced content or maturation of IL-1b and ASC speck in the food pad. The number and height of intestinal villi were decreased by colchicine but not by SLC3037.ConclusionSLC3037, a NLRP3 inhibitor blocking NEK7 binding to NLRP3, could be a novel agent against diseases associated with NLRP3 inflammasome activation such as gout, cardiovascular diseases, metabolic syndrome or neurodegenerative diseases. </p

Discovery of a benzo[e]pyrimido-[5,4-b][1,4]diazepin-6(11H)-one as a Potent and Selective Inhibitor of Big MAP Kinase 1

Kinome-wide selectivity profiling of a collection of 2-amino-pyrido[2,3-d]pyrimidines followed by cellular structure−activity relationship-guided optimization resulted in the identification of moderately potent and selective inhibitors of BMK1/ERK5 exemplified by <b>11</b>, <b>18</b>, and <b>21</b>. For example, <b>11</b> possesses a dissociation constant (<i>K</i>_d) for BMK1 of 19 nM, a cellular IC₅₀ for inhibiting epidermal growth factor induced BMK1 autophosphorylation of 0.19 ± 0.04 μM, and an Ambit KINOME<i>scan</i> selectivity score (<i>S</i>₅) of 0.035. Inhibitors <b>18</b> and <b>21</b> are also potent BMK1 inhibitors and possess favorable pharmacokinetic properties which enable their use as pharmacological probes of BMK1-dependent phenomena as well as starting points for further optimization efforts

Structure Assignment of Lucentamycin E and Revision of the Olefin Geometries of the Marine-Derived Lucentamycins

A new lucentamycin analogue, lucentamycin E (<b>5</b>), was isolated from the culture broth of the marine-derived actinomycete <i>Nocardiopsis lucentensis</i>, strain CNR-712. The absolute stereostructure of <b>5</b> was assigned by comprehensive analyses of NMR data and by application of the advanced Marfey’s method. The planar structure of <b>5</b> was analogous to lucentamycins A–D, whereas the olefin geometry of the 3-methyl-4-ethylideneproline moiety was found to be <i>E</i>, opposite of that previously reported. Consequently, a reinvestigation of the olefin geometries of the 3-methyl-4-ethylideneproline residues of lucentamycins A–D showed that the olefin geometries of the substituted proline functionalities must be revised to (2<i>S</i>,3<i>R</i>,<i>E</i>)-3-methyl-4-ethylideneproline

Discovery of Inhibitors That Overcome the G1202R Anaplastic Lymphoma Kinase Resistance Mutation

The treatment of patients with advanced non-small-cell lung cancer harboring chromosomal rearrangements of anaplastic lymphoma kinase (ALK) has been revolutionized by the development of crizotinib, a small-molecule inhibitor of ALK, ROS1, and MET. However, resistance to crizotinib inevitably develops through a variety of mechanisms, leading to relapse both systemically and in the central nervous system (CNS). This has motivated the development of “second-generation” ALK inhibitors, including alectinib and ceritinib, that overcome some of the mutations leading to resistance. However, most of the reported ALK inhibitors do not show inhibition of the G1202R mutant, which is one of the most common mutations. Herein, we report the development of a structural analogue of alectinib (JH-VIII-157-02) that is potent against the G1202R mutant as well as a variety of other frequently observed mutants. In addition, JH-VIII-157-02 is capable of penetrating the CNS of mice following oral dosing