Optimization of the 4-anilinoquin(az)oline scaffold as epidermal growth factor receptor (EGFR) inhibitors for chordoma utilizing a toxicology profiling assay platform.

The 4-anilinoquin(az)oline is a well-known kinase inhibitor scaffold incorporated in clinical inhibitors including gefitinib, erlotinib, afatinib, and lapatinib, all of which have previously demonstrated activity against chordoma cell lines in vitro. We screened a focused array of compounds based on the 4-anilinoquin(az)oline scaffold against both U-CH1 and the epidermal growth factor receptor (EGFR) inhibitor resistant U-CH2. To prioritize the hit compounds for further development, we screened the compound set in a multiparameter cell health toxicity assay. The de-risked compounds were then screened against a wider panel of patient derived cell lines and demonstrated low micromolar efficacy in cells. We also investigated the properties that gave rise to the toxophore markers, including the structural and electronic features, while optimizing for EGFR in-cell target engagement. These de-risked leads present a potential new therapeutic avenue for treatment of chordomas and new chemical tools and probe compound 45 (UNC-CA359) to interrogate EGFR mediated disease phenotypes.

Design of a Cyclin G Associated Kinase (GAK)/Epidermal Growth Factor Receptor (EGFR) Inhibitor Set to Interrogate the Relationship of EGFR and GAK in Chordoma.

We describe the design of a set of inhibitors to investigate the relationship between cyclin G associated kinase (GAK) and epidermal growth factor receptor (EGFR) in chordoma bone cancers. These compounds were characterized both in vitro and using in cell target engagement assays. The most potent chordoma inhibitors were further characterized in a kinome-wide screen demonstrating narrow spectrum profiles. While we observed a direct correlation between EGFR and antiproliferative effects on chordoma, GAK inhibition appeared to have only a limited effect.

Lipidation of an FlrC-dependent protein is required for enhanced intestinal colonization by Vibrio cholerae.

Vibrio cholerae, the causative agent of cholera, has a sheathed, polar flagellum, and motility has been linked to virulence. An operon with two genes, flgO and flgP (VC2207 and VC2206), is positively regulated by FlrC, the activator of class III flagellar genes. Deletion of flgP results in a nonmotile phenotype, demonstrating the requirement of this gene for V. cholerae motility. V. cholerae delta flgP cells synthesize fragile and defective flagella but transcribe flagellar genes similar to the wild-type strain. PhoA fusion analysis indicated that the putative lipoprotein FlgP is localized external to the cytoplasm, and fractionation demonstrated that it was localized to the outer membrane. Mutagenesis of the site of lipidation of FlgP (C18G) prevented [3H]palmitate incorporation and outer membrane localization. Interestingly, FlgP with the mutation C18G [FlgP(C18G)] could complement the delta flgP mutant for motility, and the cells synthesized wild-type flagella. The delta flgP mutant strain was defective for intestinal colonization (approximately 20-fold), but FlgP(C18G) was unable to complement this defect, demonstrating that lipidation of FlgP is essential for its role in intestinal colonization but not flagellar synthesis. FlgP thus represents a novel V. cholerae intestinal colonization factor that is regulated by the flagellar transcription hierarchy.

Nck deficiency is associated with delayed breast carcinoma progression and reduced metastasis.

Although it is known that noncatalytic region of tyrosine kinase (Nck) regulates cell adhesion and migration by bridging tyrosine phosphorylation with cytoskeletal remodeling, the role of Nck in tumorigenesis and metastasis has remained undetermined. Here we report that Nck is required for the growth and vascularization of primary tumors and lung metastases in a breast cancer xenograft model as well as extravasation following injection of carcinoma cells into the tail vein. We provide evidence that Nck directs the polarization of cell-matrix interactions for efficient migration in three-dimensional microenvironments. We show that Nck advances breast carcinoma cell invasion by regulating actin dynamics at invadopodia and enhancing focalized extracellular matrix proteolysis by directing the delivery and accumulation of MMP14 at the cell surface. We find that Nck-dependent cytoskeletal changes are mechanistically linked to enhanced RhoA but restricted spatiotemporal activation of Cdc42. Using a combination of protein silencing and forced expression of wild-type/constitutively active variants, we provide evidence that Nck is an upstream regulator of RhoA-dependent, MMP14-mediated breast carcinoma cell invasion. By identifying Nck as an important driver of breast carcinoma progression and metastasis, these results lay the groundwork for future studies assessing the therapeutic potential of targeting Nck in aggressive cancers.

Tapinarof Is a Natural AhR Agonist that Resolves Skin Inflammation in Mice and Humans.

Tapinarof (GSK2894512) is a naturally derived topical treatment with demonstrated efficacy for patients with psoriasis and atopic dermatitis, although the biologic target and mechanism of action had been unknown. We demonstrate that the anti-inflammatory properties of tapinarof are mediated through activation of the aryl hydrocarbon receptor (AhR). We show that tapinarof binds and activates AhR in multiple cell types, including cells of the target tissue-human skin. In addition, tapinarof moderates proinflammatory cytokine expression in stimulated peripheral blood CD4+ T cells and ex vivo human skin, and impacts barrier gene expression in primary human keratinocytes; both of these processes are likely to be downstream of AhR activation based on current evidence. That the anti-inflammatory properties of tapinarof derive from AhR agonism is conclusively demonstrated using the mouse model of imiquimod-induced psoriasiform skin lesions. Topical treatment of AhR-sufficient mice with tapinarof leads to compound-driven reductions in erythema, epidermal thickening, and tissue cytokine levels. In contrast, tapinarof has no impact on imiquimod-induced skin inflammation in AhR-deficient mice. In summary, these studies identify tapinarof as an AhR agonist and confirm that its efficacy is dependent on AhR.

Reticulate evolution in the natural range of the invasive wetland tree species Melaleuca quinquenervia.

The Melaleuca leucadendra complex (broad-leaf paperbarks; Myrtaceae) is a dominant component of the tropical and sub-tropical biota of Australia, particularly in wetlands of high conservation significance. In Florida and other parts of the Americas, however, one member of the group (Melaleuca quinquenervia) is a serious ecological and economic weed. Understanding the relationships and evolution of the group is integral to both conservation and biocontrol efforts. Although the complex is currently considered to include up to 14 species, there has been some concern over taxonomic boundaries within the complex because most species are circumscribed only by combinations of characters, each of which also occurs in other species. Here, DNA sequence data derived from the chloroplast and two nuclear regions are used to explore the relationships of M. quinquenervia. We find little evidence for clear species boundaries within the M. leucadendra complex in general, with regional sharing of chloroplast haplotypes across morphologically defined taxa, indicating asymmetrical introgression or retention of ancestral haplotypes (lineage sorting). Phylogenies were further confounded by the recovery of multiple copies of both nuclear regions sequenced (ITS and rpb2) from many individuals. There was no clear evidence of polyploidy or pseudogenes, but multiple duplications of rpb2 could not be ruled out. Parsimony networks of the nuclear ITS region show some clustering of haplotypes by morphospecies but there is also evidence of both hybridisation and recombination. Signals of introgression were also evident in rpb2, supporting an hypothesis of recent or ongoing gene flow between M. quinquenervia and other members of the M. leucadendra complex. Both relaxed and fixed molecular-clock dating estimate the introgression to have occurred sometime within the past seven million years (95% CI: 0.7-18). The New Caledonian population of M. quinquenervia appears to have been established by dispersal from Australia during this period. M. quinquenervia is found to have alleles closely related to multiple different morphotaxa within the M. leucadendra complex, suggesting considerable past introgression into this taxon from some other members of the M. leucadendra complex, and this has implications for biocontrol efforts. The M. leucadendra complex appears to reflect early to intermediate stages of speciation, possibly driven by different ecologies.

Phylogenetics of Australian Acacia thrips: the evolution of behaviour and ecology.

The species of thrips found on Acacia constitute a major component of the Australian thrips fauna, with at least 235 species in more than 30 genera, many of these being in the process of description as new. These thrips exhibit social behaviours, ranging from solitary and colonial species to a variety of more complex social organisations. Furthermore, the domiciliary habits of these species include domicile construction, gall induction, and opportunistic use of abandoned galls and domiciles. This suite of thrips also includes a variety of inquiline and kleptoparasitic taxa. To understand how these various traits have evolved and interact in this diverse group, we have reconstructed a phylogeny for 42 species of thrips associated with Acacia around Australia. We obtained DNA sequence data from two nuclear genes (Elongation Factor-1alpha and wingless) and one mitochondrial gene (cytochrome oxidase I) and analysed these using maximum parsimony and maximum likelihood methods. A phylogeny resulting from such analysis allows inference of evolutionary transitions in domiciliary habits, social organisations, and parasitic behaviours. Gall induction and parasitic behaviour are postulated to each have a single origin, with no losses of either trait. Once parasitism evolved a remarkable radiation followed that allowed exploitation of very diverse hosts. Our data do not allow hypotheses of single versus multiple origins of domicile building to be resolved while opportunistic gall use appears to have arisen several times.