Protein-protein interactions with G3BPs drive stress granule condensation and gene expression changes under cellular stress.

Stress granules (SGs) are macromolecular assemblies that form under cellular stress. Formation of these condensates is driven by the condensation of RNA and RNA-binding proteins such as G3BPs. G3BPs condense into SGs following stress-induced translational arrest. Three G3BP paralogs (G3BP1, G3BP2A, and G3BP2B) have been identified in vertebrates. However, the contribution of different G3BP paralogs to stress granule formation and stress-induced gene expression changes is incompletely understood. Here, we identified key residues for G3BP condensation such as V11. This conserved amino acid is required for formation of the G3BP-Caprin-1 complex, hence promoting SG assembly. Total RNA sequencing and ribosome profiling revealed that disruption of G3BP condensation corresponds to changes in mRNA levels and ribosome engagement during the integrated stress response (ISR). Moreover, we found that G3BP2B preferentially condenses and promotes changes in mRNA expression under endoplasmic reticulum (ER) stress. Together, this work suggests that stress granule assembly promotes changes in gene expression under cellular stress, which is differentially regulated by G3BP paralogs.

3-Ferrocenyl-estra-1,3,5 (10)-triene-17-one: Synthesis, Crystal Structure, Hirshfeld Surface Analysis, DFT Studies, and Its Binding to Human Serum Albumin Studied through Fluorescence Quenching and In Silico Docking Studies.

3-ferrocenyl-estra-1,3,5 (10)-triene-17-one (2), [Fe(C5H5)(C24H25O3)], crystallizes in the monoclinic space group C2. The cyclopentadienyl (Cp) rings adopt a nearly eclipsed conformation, and the Cp plane is tilted by 87.66° with respect to the substituted phenyl plane. An average Fe-C(Cp) bond length of 2.040(13) Å was determined, similar to the one reported for ferrocene. Hirshfeld surfaces and two-dimensional fingerprint plots were generated to analyze weak intermolecular C-H···π and C-H···O interactions. Density functional theory studies revealed a 1.15 kcal/mol rotational barrier for the C3-O1 single bound. Fluorescence quenching studies and in silico docking studies suggest that human serum albumin forms a complex with 2 via a static mechanism dominated by van der Waals interactions and hydrogen bonding interactions.

A survey of the kinome pharmacopeia reveals multiple scaffolds and targets for the development of novel anthelmintics.

Over one billion people are currently infected with a parasitic nematode. Symptoms can include anemia, malnutrition, developmental delay, and in severe cases, death. Resistance is emerging to the anthelmintics currently used to treat nematode infection, prompting the need to develop new anthelmintics. Towards this end, we identified a set of kinases that may be targeted in a nematode-selective manner. We first screened 2040 inhibitors of vertebrate kinases for those that impair the model nematode Caenorhabditis elegans. By determining whether the terminal phenotype induced by each kinase inhibitor matched that of the predicted target mutant in C. elegans, we identified 17 druggable nematode kinase targets. Of these, we found that nematode EGFR, MEK1, and PLK1 kinases have diverged from vertebrates within their drug-binding pocket. For each of these targets, we identified small molecule scaffolds that may be further modified to develop nematode-selective inhibitors. Nematode EGFR, MEK1, and PLK1 therefore represent key targets for the development of new anthelmintic medicines.

Synthesis, structure, docking and cytotoxic studies of ferrocene-hormone conjugates for hormone-dependent breast cancer application.

Previously, ferrocene incorporation into the principal structural component of biologically active molecules resulted in enhanced cytotoxic activity against hormone-dependent MCF-7 and T-47D and hormone-independent MDA-MB-231 breast-cancer cell lines. Here we explore 4 new ferrocene estrogen conjugates at position 16 of the estrogen hormone and compared them to the previously reported ferrocene estrogen conjugate 3-ferrocenyl-estra-1,3,5(10)-triene-17ß-ol. The ferrocene conjugate 16-ferrocenylidene-3-hydroxyestra-1,3,5(10)-trien-17-one was synthesized using estrone and ferrocene carboxaldehyde as starting materials in 86% yield. This ferrocene complex was used as the starting material for the synthesis of new ferrocene estrogen conjugates by a short linker group at position 16 of the estrogen hormone. The position and stereochemistry of the linker was verified by its crystal structure. The ferrocene redox behavior, in vitro studies on breast-cancer cell lines and docking studies on ERα are presented. The data suggest that the ferrocene conjugates presented, either at position 3 or 16 of the estrogen, could serve as vectors and can be recognized by ERα as a delivery mechanism into the cell. These new ferrocene hormone conjugates showed cytotoxic activity comparable to that of conventional therapeutic drugs such as tamoxifen and cisplatin.

Crystal structure of 16-ferrocenylmethyl-3ß-hydroxy-estra-1,3,5(10)-trien-17-one: a potential chemotherapeutic drug.

A new ferrocene complex, 16-ferrocenylmethyl-3ß-hy-droxy-estra-1,3,5(10)-trien-17-one dimethyl sulfoxide monosolvate, [Fe(C5H5)(C24H27O2)]·C2H6OS, has been synthesized and structurally characterized by single-crystal X-ray diffraction techniques. The mol-ecule crystallizes in the space group P21 with one mol-ecule of dimethyl sulfoxide. A hydrogen bond links the phenol group and the dimethyl sulfoxide O atom, with an O⋯O distance of 2.655 (5) Å. The ferrocene group is positioned in the ß face of the estrone moiety, with an O-C-C-C torsion angle of 44.1 (5)°, and the carbonyl bond length of the hormone moiety is 1.216 (5) Å, typical of a C=O double bond. The average Fe-C bond length of the substituted Cp ring [Fe-C(Cp*)] is similar to that of the unsubstituted one [Fe-C(Cp)], i.e. 2.048 (3) versus 2.040 (12) Å. The structure of the complex is compared with those of estrone and eth-oxy-methyl-estrone.

New platinum(II) complexes with benzo-thia-zole ligands.

Four new platinum(II) complexes, namely tetra-ethyl-ammonium tri-bromido-(2-methyl-1,3-benzo-thia-zole-κN)platinate(II), [NEt4][PtBr3(C8H7NS)] (1), tetra-ethyl-ammonium tri-bromido-(6-meth-oxy-2-methyl-1,3-benzo-thia-zole-κN)platinate(II), [NEt4][PtBr3(C9H9NOS)] (2), tetra-ethyl-ammonium tri-bromido-(2,5,6-trimethyl-1,3-benzo-thia-zole-κN)platinate(II), [NEt4][PtBr3(C10H11NS)] (3), and tetra-ethyl-ammonium tri-bromido-(2-methyl-5-nitro-1,3-benzo-thia-zole-κN)platinate(II), [NEt4][PtBr3(C8H6N2O2S)] (4), have been synthesized and structurally characterized by single-crystal X-ray diffraction techniques. These species are precursors of compounds with potential application in cancer chemotherapy. All four platinum(II) complexes adopt the expected square-planar coordination geometry, and the benzo-thia-zole ligand is engaged in bonding to the metal atom through the imine N atom (Pt-N). The Pt-N bond lengths are normal: 2.035 (5), 2.025 (4), 2.027 (5) and 2.041 (4) Šfor complexes 1, 2, 3 and 4, respectively. The benzo-thia-zole ligands are positioned out of the square plane, with dihedral angles ranging from 76.4 (4) to 88.1 (4)°. The NEt4 cation in 3 is disordered with 0.57/0.43 occupancies.