Elaboration of tetra-orthogonally-substituted aromatic scaffolds towards novel EGFR-kinase inhibitors

Nitration of three regioisomers of bromo-fluorobenzaldehyde proceeds regioselectively, notably with H2SO4/HNO3 at 0 °C. The thereby synthesized tetrasubstituted aromatics, endowed with orthogonal substituents, can be elaborated via Pd-catalysed coupling, reduction and reductive amination reactions. As a test-case, these compounds were converted into EGFR inhibitors related to Gefitinib, whose activity was rationalised by docking studies

Palmitoyl transferase ZDHHC20 promotes pancreatic cancer metastasis

Metastasis is one of the defining features of pancreatic ductal adenocarcinoma (PDAC) that contributes to poor prognosis. In this study, the palmitoyl transferase ZDHHC20 was identified in an in vivo shRNA screen as critical for metastatic outgrowth, with no effect on proliferation and migration in vitro, or primary PDAC growth in mice. This phenotype is abrogated in immunocompromised animals, and in animals with depleted natural killer (NK) cells, indicating that ZDHHC20 affects the interaction of tumour cells and the innate immune system. Using a chemical genetics platform for ZDHHC20-specific substrate profiling, a number of novel substrates of this enzyme were identified. These results describe a role for palmitoylation in enabling distant metastasis that could not have been detected using in vitro screening approaches and identify potential effectors through which ZDHHC20 promotes metastasis of PDAC

Synthesis of kinase inhibitors containing a pentafluorosulfanyl moiety

A series of 3-methylidene-1H-indol-2(3H)-ones substituted with a 5- or 6- pentafluorosulfanyl group has been synthesized by a Knoevenagel condensation reaction of SF5-substituted oxindoles with a range of aldehydes. The resulting products were characterized by x-ray crystallography studies and were tested for biological activity versus a panel of cell lines and protein kinases. Some exhibited single digit nM activity

Genotoxicity and epigenotoxicity of carbazole-derived molecules on mcf-7 breast cancer cells

The carbazole compounds PK9320 (1-(9-ethyl-7-(furan-2-yl)-9H-carbazol-3-yl)-N-methylmethanamine) and PK9323 (1-(9-ethyl-7-(thiazol-4-yl)-9H-carbazol-3-yl)-N-methylmethanamine), second-generation analogues of PK083 (1-(9-ethyl-9H-carbazol-3-yl)-N-methylmethanamine), restore p53 signaling in Y220C p53-mutated cancer cells by binding to a mutation-induced surface crevice and acting as molecular chaperones. In the present paper, these three molecules have been tested for mutant p53-independent genotoxic and epigenomic effects on wild-type p53 MCF-7 breast adenocarcinoma cells, employing a combination of Western blot for phospho-γH2AX histone, Comet assay and methylation-sensitive arbitrarily primed PCR to analyze their intrinsic DNA damageinducing and DNA methylation-changing abilities. We demonstrate that small modifications in the substitution patterns of carbazoles can have profound effects on their intrinsic genotoxic and epigenetic properties, with PK9320 and PK9323 being eligible candidates as “anticancer compounds” and “anticancer epi-compounds” and PK083 a “damage-corrective” compound on human breast adenocarcinoma cells. Such different properties may be exploited for their use as anticancer agents and chemical probes

A palmitoyl transferase chemical genetic system to map ZDHHC-specific S-acylation

The 23 human ZDHHC S-acyltransferases catalyze long-chain S-acylation at cysteine residues across an extensive network of hundreds of proteins important for normal physiology or dysregulated in disease. Here we present a technology platform to directly map the protein substrates of a specific ZDHHC for the first time at the whole proteome level, in intact cells. Structure-guided engineering of paired ZDHHC ‘hole’ mutants and ‘bumped’ chemically tagged fatty acid probes enabled probe transfer to specific protein substrates with excellent selectivity over wild type ZDHHCs. Chemical genetic systems were exemplified for five ZDHHCs (3, 7, 11, 15 and 20), and applied to generate the first de novo ZDHHC substrate profiles, identifying >300 unique and shared substrates across multiple cell lines and Sacylation sites for novel functionally diverse substrates. We expect that this powerful and versatile platform will open a new window on S-acylation biology for a wide range of models and organisms

Ferrocenes in medicinal chemistry; a personal perspective

We present a short review of some of our recent work mainly targeting cancer-related oncoproteins through the development of primarily novel air- and water- stable iron-based organometallic agents. This work was presented at the recent ISBOMC19 conference at York as an invited lecture

PP2A/B55 and Fcp1 regulate Greatwall and Ensa desphorylation during mitotic exit

Entry into mitosis is triggered by activation of Cdk1 and inactivation of its counteracting phosphatase PP2A/B55. Greatwall kinase inactivates PP2A/B55 via its substrates Ensa and ARPP19. Both Greatwall and Ensa/ARPP19 are regulated by phosphorylation, but the dynamic regulation of Greatwall activity and the phosphatases that control Greatwall kinase and its substrates are poorly understood. To address these questions we applied a combination of mathematical modelling and experiments using phospho-specific antibodies to monitor Greatwall, Ensa/ARPP19 and Cdk substrate phosphorylation during mitotic entry and exit. We demonstrate that PP2A/B55 is required for Gwl dephosphorylation at the essential Cdk site Thr194. Ensa/ARPP19 dephosphorylation is mediated by the RNA Polymerase II carboxy terminal domain phosphatase Fcp1. Surprisingly, neither Fcp1 nor PP2A appear to essential to dephosphorylate the bulk of mitotic Cdk1 substrates following Cdk1 inhibition. Taken together our results suggest a hierarchy of phosphatases coordinating Greatwall, Ensa/ARPP19 and Cdk substrate dephosphorylation during mitotic exit

Synthesis and biological investigation of (+)-JD1, an organometallic BET bromodomain inhibitor

(+)-JD1, a rationally designed ferrocene analogue of the BET bromodomain (BRD) probe molecule (+)-JQ1, has been synthesized and evaluated in biophysical, cell-based assays as well as in pharmacokinetic studies. It displays nanomolar activity against BRD isoforms, and its cocrystal structure was determined in complex with the first bromodomain of BRD4 and compared with that of (+)-JQ1, a known BRD4 small-molecule probe. At 1 μM concentration, (+)-JD1 was able to inhibit c-Myc, a key driver in cancer and an indirect target of BRD4

Design and Characterization of Novel Thyroid Hormone Receptor Alpha Specific Ligands

Thyroid hormone orchestrates a multifarious set of physiological activities ranging from fetal, brain, and skeletal maturation to improving vascular tone and controlling cardiac output. Thyroid hormone elicits its effects by binding to the ligand binding domain of the thyroid hormone receptor (TR) for which there are two subtypes for two isoforms: TRα1, TRα2, TRβ1, and TRβ2. Although TR isoforms, with the exception of TRβ2 which is mainly expressed in the pituitary, are ubiquitously expressed, these isoforms are expressed in different ratios in different tissues giving rise to tissue-specific isoform action. Selective thyroid hormone analogues, or selective thyromimetics, that discriminate between these two subtypes would serve as useful chemical tools to gain or refine our understanding of the physiological effects of thyroid hormone. These compounds may also prove useful in the clinic as known thyromimetics (i.e. 3,5-diiodothyroproprionic acid and GC-1) show promise in treating cardiac related diseases and metabolic disorders. One way to generate selective thyromimetics with unique pharmacological profiles is to synthesize a small panel of compounds by employing a bioisosteric replacement strategy. This method entails derivatizing one region of the thyronine backbone, the C1 region, by incorporation of various heterocycles or carbocycles. This strategy led to the production of a small panel of ligands which were screened in 125I-T3 competitive binding and transactivation assays. After this screen, the TRα-specific ligand CO22 was identified; however, it demonstrated poor binding and potency. Replacing the inner-ring methyl groups of CO22 with iodides led to CO23, the first potent thyromimetic to show TRα-specificity in vitro and in vivo. CO23 showed specificity in TRα-mediated transcription in U2OS and HeLa cells and caused Xenopus laevis tadpoles to experience more extensive and rapid hind leg growth, less larval tissue resorption, greater induction of TRα early genes, and less induction of TRβ early and late genes. It was surmised that the imidazolidinedione moiety of the inner-ring confers TRα-specificity; therefore, to engender ligands with improved specificity the 3' outer-ring position was derivatized. This led to several analogues with less potency than CO23, but with a gain in specificity of up to 2-fold

A critique of methods used to describe the overrepresentation of African Americans in the child welfare system

The overrepresentation of minority children in the child welfare system has long been a troubling issue. Strategies to reduce this racial imbalance have typically focused on child welfare decision making at various time points in the course of a case, informed by descriptive statistics used to measure racial disproportionality and disparity at these key decision points. In this paper we make comparisons between two methods used to describe racial disproportionality and disparity in child welfare: one uses the general child population as its reference group and the other uses the child welfare population as it changes from one decision point to the next. This paper discusses and critiques these two methods, using the data from four states to illustrate the utility of each in describing racial overrepresentation in child welfare.Child welfare African Americans Overrepresentation Disproportionality Disparity