Salt-inducible kinases (SIKs) are key metabolic regulators. The imbalance in SIK function is associated with the development of diverse cancers, including breast, gastric, and ovarian cancers. Chemical tools to clarify the roles of SIK in different diseases are, however, sparse and are generally characterized by poor kinome-wide selectivity. Here, we have adapted the pyrido[2,3-d]pyrimidin-7-one-based p21-activated kinase (PAK) inhibitor G-5555 for the targeting of SIK, by exploiting differences in the back-pocket region of these kinases. Optimization was supported by high-resolution crystal structures of G-5555 bound to the known off-targets, MST3 and MST4, leading to a chemical probe, MRIA9, with dual SIK/ PAK activity and excellent selectivity over other kinases. Furthermore, we show that MRIA9 sensitizes ovarian cancer cells to treatment with the mitotic agent paclitaxel, confirming earlier data from genetic knockdown studies and suggesting a combination therapy with SIK inhibitors and paclitaxel for the treatment of paclitaxel-resistant ovarian cancer.

In total, more than 700 proteins regulate chromatin function 18,[22][23] and they are often part of multi-domain protein complexes. Beside the catalytic subunit that controls chromatin accessibility, also subunits that recognize and interact with epigenetic modifications are crucial components of histone modifying complexes. 2 Despite the three classes of epigenetic readers, erasers, and writers, also epigenetic movers, shapers and insulators interact with chromatin structure. [24][25] Proteins that recognize post-translational modifications are classified as epigenetic readers. 26 Well-studied protein families for epigenetic readers are, e.g., bromodomains (BRDs), which recognize acetylated lysine residues. The BRDs have been extensively studied and successfully drugged in cancer treatment. 26 In Table 1, the bromodomain BRD4 of the bromodomain and extraterminal domain (BET) family is listed due to its prominent role in super-enhancers (SEs) organization and regulation of oncogene expression in cancer. 27 Targeting BRD4 by inhibiting the acetyl-lysine binding site with small molecules, e.g., the first BRD targeting inhibitor (JQ1), was shown to be an effective strategy for cancers like the aggressive NUT midline carcinoma (NMC). [28][29] Beside the outstanding role of BRD4, other BRDs are involved as epigenetic readers in various nucleosome remodeling complexes: in the ATP-dependent human complexes BAF (BRG1/BRMassociated factor) and PBAF (polybromo-associated BAF factor), two bromodomains, SMARCA2/ 4 (SWI/SNF-related, matrix-associated actin-dependent regulator of chromatin, subfamily A2/ 4), perturbate with the core subunits BRG1/BRM histone-DNA contacts. [30][31][32] Mutations in BAF components are one of the most frequently observed genetic alteration in cancer. [33][34] demonstrated how mutations and misregulations of histone lysine methyltransferases (KMTs), demethylases and methyl-lysine-binding proteins are connected to various diseases, thus making them effective therapeutic targets for cancer treatments. [46][47] The histone demethylation process is carried out by lysine demethylases like LSD1 48 and the JARID1 familiy 49 epigenetic erasers that are known to be perturbed in cancer, as previously listed in Table 1. Equally involved in cancer formation is the class of histone lysine methyltransferases (KMTs) which are categorized as epigenetic writers. KMTs comprise proteins like MLL1-3 and SET1D which are relevant drug targets, as shown in the non-exhaustive list in Table 1. Within histone lysine methylation, H3K4 methylation is an evolutionary conserved motif that marks active gene transcription 50-51 and is highly enriched at the promotor region and transcription start site. 51 The family of Histone lysine Methyltransferases and its adaptor proteins are described in the following chapter.while the pink colored c-Myc peptide MbIIIb binds to WDR5 on a shallow cleft on the surface, the so called WBM side (pdb entry: 3eg6 and 4y7r).WDR5 has emerged as a promising drug target for anti-cancer therapies as i...

Modulation of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling is a promising method of treating autoimmune diseases, and the profound potency of clinical compounds makes this mode of action particularly attractive. Other questions that remain unanswered also include: What is the ideal selectivity between JAK1 and JAK3? Which cells are most relevant to JAK blockade? And what is the ideal tissue distribution pattern for addressing specific autoimmune conditions? We hypothesized that JAK3 selectivity is most relevant to low-dose clinical effects and interleukin-10 (IL-10) stimulation in particular, that immune cells are the most important compartment, and that distribution to inflamed tissue is the most important pharmacokinetic characteristic for in vivo disease modification. To test these hypotheses, we prepared modified derivatives of JAK3 specific inhibitors that target C909 near the ATP binding site based on FM-381, first reported in 2016; a compound class that was hitherto limited in uptake and exposure in vivo. These limits appear to be due to metabolic instability of side groups binding in the selectivity pocket. We identified derivatives with improved stability and tissue exposure. Conjugation to macrolide scaffolds with medium chain linkers was sufficient to stabilize the compounds and improve transport to organs while maintaining JAK3 affinity. These conjugates are inflammation targeted JAK3 inhibitors with long tissue half-lives and high exposure to activated immune cells.

Serine/threonine kinase 17A (death-associated protein kinase-related apoptosis-inducing protein kinase 1DRAK1) is a part of the death-associated protein kinase (DAPK) family and belongs to the so-called dark kinome. Thus, the current state of knowledge of the cellular function of DRAK1 and its involvement in pathophysiological processes is very limited. Recently, DRAK1 has been implicated in tumorigenesis of glioblastoma multiforme (GBM) and other cancers, but no selective inhibitors of DRAK1 are available yet. To this end, we optimized a pyrazolo­[1,5-a]­pyrimidine-based macrocyclic scaffold. Structure-guided optimization of this macrocyclic scaffold led to the development of CK156 (34), which displayed high in vitro potency (K D = 21 nM) and selectivity in kinomewide screens. Crystal structures demonstrated that CK156 (34) acts as a type I inhibitor. However, contrary to studies using genetic knockdown of DRAK1, we have seen the inhibition of cell growth of glioma cells in 2D and 3D culture only at low micromolar concentrations.

Inhibitors targeting the epidermal growth factor receptor (EGFR) are an effective therapy for patients with non-small cell lung cancer harboring drug-sensitive activating mutations in the EGFR kinase domain. Drug resistance due to treatment-acquired mutations has motivated the development of successive generations of inhibitors that bind in the ATP site. The thirdgeneration agent osimertinib is now a first-line treatment for this disease. Recently, allosteric inhibitors have been developed to overcome drug-resistant mutations that confer a resistance to osimertinib. Here, we present the structure-guided design and synthesis of a mutant-selective lead compound, which consists of a pyridinyl imidazole-fused benzylisoindolinedione scaffold that simultaneously occupies the orthosteric and allosteric sites. The compound potently inhibits enzymatic activity in L858R/T790M/C797S mutant EGFR (4.9 nM), with a significantly lower activity for wild-type EGFR (47 nM). Additionally, this compound achieves modest cetuximabindependent and mutant-selective cellular efficacies on the L858R (1.2 μM) and L858R/T790M (4.4 μM) variants.