Discovery of Potent, Selective, and Orally Bioavailable Small-Molecule Modulators of the Mediator Complex-Associated Kinases CDK8 and CDK19.

The Mediator complex-associated cyclin-dependent kinase CDK8 has been implicated in human disease, particularly in colorectal cancer where it has been reported as a putative oncogene. Here we report the discovery of 109 (CCT251921), a potent, selective, and orally bioavailable inhibitor of CDK8 with equipotent affinity for CDK19. We describe a structure-based design approach leading to the discovery of a 3,4,5-trisubstituted-2-aminopyridine series and present the application of physicochemical property analyses to successfully reduce in vivo metabolic clearance, minimize transporter-mediated biliary elimination while maintaining acceptable aqueous solubility. Compound 109 affords the optimal compromise of in vitro biochemical, pharmacokinetic, and physicochemical properties and is suitable for progression to animal models of cancer

3D imaging of colorectal cancer organoids identifies responses to Tankyrase inhibitors

Aberrant activation of the Wnt signalling pathway is required for tumour initiation and survival in the majority of colorectal cancers. The development of inhibitors of Wnt signalling has been the focus of multiple drug discovery programs targeting colorectal cancer and other malignancies associated with aberrant pathway activation. However, progression of new clinical entities targeting the Wnt pathway has been slow. One challenge lies with the limited predictive power of 2D cancer cell lines because they fail to fully recapitulate intratumoural phenotypic heterogeneity. In particular, the relationship between 2D cancer cell biology and cancer stem cell function is poorly understood. By contrast, 3D tumour organoids provide a platform in which complex cell-cell interactions can be studied. However, complex 3D models provide a challenging platform for the quantitative analysis of drug responses of therapies that have differential effects on tumour cell subpopulations. Here, we generated tumour organoids from colorectal cancer patients and tested their responses to inhibitors of Tankyrase (TNKSi) which are known to modulate Wnt signalling. Using compounds with 3 orders of magnitude difference in cellular mechanistic potency together with image-based assays, we demonstrate that morphometric analyses can capture subtle alterations in organoid responses to Wnt inhibitors that are consistent with activity against a cancer stem cell subpopulation. Overall our study highlights the value of phenotypic readouts as a quantitative method to asses drug-induced effects in a relevant preclinical model

A novel tankyrase inhibitor, MSC2504877, enhances the effects of clinical CDK4/6 inhibitors.

Inhibition of the PARP superfamily tankyrase enzymes suppresses Wnt/β-catenin signalling in tumour cells. Here, we describe here a novel, drug-like small molecule inhibitor of tankyrase MSC2504877 that inhibits the growth of APC mutant colorectal tumour cells. Parallel siRNA and drug sensitivity screens showed that the clinical CDK4/6 inhibitor palbociclib, causes enhanced sensitivity to MSC2504877. This tankyrase inhibitor-CDK4/6 inhibitor combinatorial effect is not limited to palbociclib and MSC2504877 and is elicited with other CDK4/6 inhibitors and toolbox tankyrase inhibitors. The addition of MSC2504877 to palbociclib enhances G 1 cell cycle arrest and cellular senescence in tumour cells. MSC2504877 exposure suppresses the upregulation of Cyclin D2 and Cyclin E2 caused by palbociclib and enhances the suppression of phospho-Rb, providing a mechanistic explanation for these effects. The combination of MSC2504877 and palbociclib was also effective in suppressing the cellular hyperproliferative phenotype seen in Apc defective intestinal stem cells in vivo. However, the presence of an oncogenic Kras p.G12D mutation in mice reversed the effects of the MSC2504877/palbociclib combination, suggesting one molecular route that could lead to drug resistance

A selective chemical probe for exploring the role of CDK8 and CDK19 in human disease.

There is unmet need for chemical tools to explore the role of the Mediator complex in human pathologies ranging from cancer to cardiovascular disease. Here we determine that CCT251545, a small-molecule inhibitor of the WNT pathway discovered through cell-based screening, is a potent and selective chemical probe for the human Mediator complex-associated protein kinases CDK8 and CDK19 with >100-fold selectivity over 291 other kinases. X-ray crystallography demonstrates a type 1 binding mode involving insertion of the CDK8 C terminus into the ligand binding site. In contrast to type II inhibitors of CDK8 and CDK19, CCT251545 displays potent cell-based activity. We show that CCT251545 and close analogs alter WNT pathway-regulated gene expression and other on-target effects of modulating CDK8 and CDK19, including expression of genes regulated by STAT1. Consistent with this, we find that phosphorylation of STAT1(SER727) is a biomarker of CDK8 kinase activity in vitro and in vivo. Finally, we demonstrate in vivo activity of CCT251545 in WNT-dependent tumors

A selective chemical probe for exploring the role of CDK8 and CDK19 in human disease

There is unmet need for chemical tools to explore the role of the Mediator complex in human pathologies ranging from cancer to cardiovascular disease. Here we determine that CCT251545, a small-molecule inhibitor of the WNT pathway discovered through cell-based screening, is a potent and selective chemical probe for the human Mediator complex–associated protein kinases CDK8 and CDK19 with >100-fold selectivity over 291 other kinases. X-ray crystallography demonstrates a type 1 binding mode involving insertion of the CDK8 C terminus into the ligand binding site. In contrast to type II inhibitors of CDK8 and CDK19, CCT251545 displays potent cell-based activity. We show that CCT251545 and close analogs alter WNT pathway–regulated gene expression and other on-target effects of modulating CDK8 and CDK19, including expression of genes regulated by STAT1. Consistent with this, we find that phosphorylation of STAT1SER727 is a biomarker of CDK8 kinase activity in vitro and in vivo. Finally, we demonstrate in vivo activity of CCT251545 in WNT-dependent tumors

Clinical Information Systems – Seen through the Ethics Lens

Objective: The more people there are who use clinical information systems (CIS) beyond their traditional intramural confines, the more promising the benefits are, and the more daunting the risks will be. This review thus explores the areas of ethical debates prompted by CIS conceptualized as smart systems reaching out to patients and citizens. Furthermore, it investigates the ethical competencies and education needed to use these systems appropriately. Methods: A literature review covering ethics topics in combination with clinical and health information systems, clinical decision support, health information exchange, and various mobile devices and media was performed searching the MEDLINE database for articles from 2016 to 2019 with a focus on 2018 and 2019. A second search combined these keywords with education. Results: By far, most of the discourses were dominated by privacy, confidentiality, and informed consent issues. Intertwined with confidentiality and clear boundaries, the provider-patient relationship has gained much attention. The opacity of algorithms and the lack of explicability of the results pose a further challenge. The necessity of sociotechnical ethics education was underpinned in many studies including advocating education for providers and patients alike. However, only a few publications expanded on ethical competencies. In the publications found, empirical research designs were employed to capture the stakeholders’ attitudes, but not to evaluate specific implementations. Conclusion: Despite the broad discourses, ethical values have not yet found their firm place in empirically rigorous health technology evaluation studies. Similarly, sociotechnical ethics competencies obviously need detailed specifications. These two gaps set the stage for further research at the junction of clinical information systems and ethics