Feedback from the Science Café roundtables at the ninth European Bioanalysis Forum Young Scientist Symposium: optimizing the work-life balance in a bioanalytical laboratory.

As part of the European Bioanalysis Forum's continued commitment to develop young scientists beyond their scientific skills, we also focus on soft skills and a community responsibility during the Young Scientist Symposia, with the Science Café. In previous years, we have focused on topics such as sustainability (green lab) or the impact of the COVID-19 pandemic on career development. At the ninth Young Scientist Symposium, the Science Café roundtables focused on the work-life balance and how caring for it can be beneficial for both the individual and the company. Feedback from a premeeting survey and from the discussions during the roundtables can be an important addition to personal and professional development. If organizations are not already focusing on the importance of a healthy work-life balance, they can be inspired to include some aspects of the outcome of the Science Café discussions when developing their staff toward future (scientific) leadership.

AT7867 is a potent and oral inhibitor of AKT and p70 S6 kinase that induces pharmacodynamic changes and inhibits human tumor xenograft growth.

The serine/threonine kinase AKT plays a pivotal role in signal transduction events involved in malignant transformation and chemoresistance and is an attractive target for the development of cancer therapeutics. Fragment-based lead discovery, combined with structure-based drug design, has recently identified AT7867 as a novel and potent inhibitor of both AKT and the downstream kinase p70 S6 kinase (p70S6K) and also of protein kinase A. This ATP-competitive small molecule potently inhibits both AKT and p70S6K activity at the cellular level, as measured by inhibition of GSK3beta and S6 ribosomal protein phosphorylation, and also causes growth inhibition in a range of human cancer cell lines as a single agent. Induction of apoptosis was detected by multiple methods in tumor cells following AT7867 treatment. Administration of AT7867 (90 mg/kg p.o. or 20 mg/kg i.p.) to athymic mice implanted with the PTEN-deficient U87MG human glioblastoma xenograft model caused inhibition of phosphorylation of downstream substrates of both AKT and p70S6K and induction of apoptosis, confirming the observations made in vitro. These doses of AT7867 also resulted in inhibition of human tumor growth in PTEN-deficient xenograft models. These data suggest that the novel strategy of AKT and p70S6K blockade may have therapeutic value and supports further evaluation of AT7867 as a single-agent anticancer strategy.

Discovery of 4-amino-1-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)piperidine-4-carboxamides as selective, orally active inhibitors of protein kinase B (Akt).

Protein kinase B (PKB or Akt) is an important component of intracellular signaling pathways regulating growth and survival. Signaling through PKB is frequently deregulated in cancer, and inhibitors of PKB therefore have potential as antitumor agents. The optimization of lipophilic substitution within a series of 4-benzyl-1-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)piperidin-4-amines provided ATP-competitive, nanomolar inhibitors with up to 150-fold selectivity for inhibition of PKB over the closely related kinase PKA. Although active in cellular assays, compounds containing 4-amino-4-benzylpiperidines underwent metabolism in vivo, leading to rapid clearance and low oral bioavailability. Variation of the linker group between the piperidine and the lipophilic substituent identified 4-amino-1-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)piperidine-4-carboxamides as potent and orally bioavailable inhibitors of PKB. Representative compounds modulated biomarkers of signaling through PKB in vivo and strongly inhibited the growth of human tumor xenografts in nude mice at well-tolerated doses.

Identification of N-(4-piperidinyl)-4-(2,6-dichlorobenzoylamino)-1H-pyrazole-3-carboxamide (AT7519), a novel cyclin dependent kinase inhibitor using fragment-based X-ray crystallography and structure based drug design.

The application of fragment-based screening techniques to cyclin dependent kinase 2 (CDK2) identified multiple (>30) efficient, synthetically tractable small molecule hits for further optimization. Structure-based design approaches led to the identification of multiple lead series, which retained the key interactions of the initial binding fragments and additionally explored other areas of the ATP binding site. The majority of this paper details the structure-guided optimization of indazole (6) using information gained from multiple ligand-CDK2 cocrystal structures. Identification of key binding features for this class of compounds resulted in a series of molecules with low nM affinity for CDK2. Optimisation of cellular activity and characterization of pharmacokinetic properties led to the identification of 33 (AT7519), which is currently being evaluated in clinical trials for the treatment of human cancers.

Application of fragment screening and fragment linking to the discovery of novel thrombin inhibitors.

The screening of fragments is an alternative approach to high-throughput screening for the identification of leads for therapeutic targets. Fragment hits have been discovered using X-ray crystallographic screening of protein crystals of the serine protease enzyme thrombin. The fragment library was designed to avoid any well-precedented, strongly basic functionality. Screening hits included a novel ligand (3), which binds exclusively to the S2-S4 pocket, in addition to smaller fragments which bind to the S1 pocket. The structure of these protein-ligand complexes are presented. A chemistry strategy to link two such fragments together and to synthesize larger drug-sized compounds resulted in the efficient identification of hybrid inhibitors with nanomolar potency (e.g., 7, IC50 = 3.7 nM). These potent ligands occupy the same area of the active site as previously described peptidic inhibitors, while having very different chemical architecture.

Structure-based design of isoquinoline-5-sulfonamide inhibitors of protein kinase B.

Structure-based drug design of novel isoquinoline-5-sulfonamide inhibitors of PKB as potential antitumour agents was investigated. Constrained pyrrolidine analogues that mimicked the bound conformation of linear prototypes were identified and investigated by co-crystal structure determinations with the related protein PKA. Detailed variation in the binding modes between inhibitors with similar overall conformations was observed. Potent PKB inhibitors from this series inhibited GSK3beta phosphorylation in cellular assays, consistent with inhibition of PKB kinase activity in cells.

Identification of novel p38alpha MAP kinase inhibitors using fragment-based lead generation.

We describe the structure-guided optimization of the molecular fragments 2-amino-3-benzyloxypyridine 1 (IC(50) 1.3 mM) and 3-(2-(4-pyridyl)ethyl)indole 2 (IC(50) 35 microM) identified using X-ray crystallographic screening of p38alpha MAP kinase. Using two separate case studies, the article focuses on the key compounds synthesized, the structure-activity relationships and the binding mode observations made during this optimization process, resulting in two potent lead series that demonstrate significant increases in activity. We describe the process of compound elaboration either through the growing out from fragments into adjacent pockets or through the conjoining of overlapping fragments and demonstrate that we have exploited the mobile conserved activation loop, consisting in part of Asp168-Phe169-Gly170 (DFG), to generate significant improvements in potency and kinase selectivity.