Conformational control of anticancer activity: the application of arene-linked dinuclear ruthenium(II) organometallics

Dinuclear metal complexes have emerged as a promising class of biologically active compounds which possess unique anticancer activity. Here, we describe a novel series of arene-linked dinuclear organometallic Ru(II) complexes, where the relative conformation of the ruthenium centres is controlled by the stereochemical configuration of 1,2-diphenylethylenediamine linker moieties, as confirmed by X-ray crystallography. The reactivity and cytotoxicity of these compounds is compared to flexible dinuclear and mononuclear analogues, demonstrating in all cases the complexes can undergo aquation, coordinate to typical biological donor ligands and importantly, in the case of dinuclear analogues, crosslink oligonucleotide and peptide sequences. Differences in the conformation of the isomeric dinuclear compounds lead to significantly different levels of cytotoxicity against A2780, A2780cisR and HEK-293 cell lines; isomers with a closed conformation are significantly more cytotoxic than isomers with a more open conformation and they are also significantly less susceptible to acquired resistance mechanisms operating in the A2780cisR cell line. These rigid dinuclear compounds possess markedly increased cytotoxicity relative to the non-cytotoxic mononuclear analogues that does not appear to be related to differences in complex lipophilicity or cellular uptake, which, in general, remain similar in magnitude across the series. Thus, the molecular conformation of such dinuclear species may be crucial in determining the nature of the adducts formed on coordination to biological targets in a cellular environment, and opens up a novel route toward the development of more active metal-based anticancer agents

Versatile Tool for the Analysis of Metal-Protein Interactions Reveals the Promiscuity of Metallodrug-Protein Interactions

Metallodrug protein interactions contribute to their therapeutic effect (even when DNA is the dominant target), side-effects and are implicit in drug resistance. Here, we provide mass spectrometric-based evidence to show that metallodrug interactions with proteins are considerably more complex than current literature would suggest. Using native-like incubation and electrospray conditions together with an automated tool we designed for exhaustive mass spectra matching, the promiscuity of binding of cisplatin to ubiquitin is revealed, with 14 different binding sites observed. There is a binding preference to negatively charged sites on the protein, consistent with the cationic nature of the cisplatin adduct following aquation. These results have implications in metallodrug development and beyond to the toxicological effects of metal ions more generally

The Intestinal Microbiota Contributes to the Ability of Helminths to Modulate Allergic Inflammation

We thank Manuel Kulagin for technical help, Pierre Bonnaventure for portal vein blood sampling, Francisco Sepulveda for technical assistance in GS-MS acquisition, and Dorothee Hahne (Metabolomics Australia, University of Western Australia) for human samples SCFA isolation, acquisition, and analysis. We also thank Cristina Cartoni (Phenotyping Unit, EPFL) for Milliplex analysis, Jessica Dessimoz and her team from the Histology Core Facility (EPFL), Miguel Garcia and his team from the Flow Cytometry Core Facility (EPFL), and staff from the EPFL CPG animal house for excellent animal care. The computations were partially performed at the Vital-IT Center for high-performance computing of the SIB Swiss Institute of Bioinformatics (http://www.vital-it.ch). The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 310948. Funding for A.W.W. and a subset of the 16S rRNA gene sequencing was provided by the Wellcome Trust (grant number WT 098051). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Oxaliplatin reacts with DMSO only in the presence of water

Herein we show that oxaliplatin reacts rapidly with DMSO in aqueous solutions, despite being stable in pure DMSO and pure water. Furthermore, the reactivity of the clinically applied Pt(II) drugs in water/DMSO and PBS/DMSO mixtures, and the nature of the species formed were investigated by MS, NMR and RP-HPLC techniques

Oral transfer of chemical cues, growth proteins and hormones in social insects.

Social insects frequently engage in oral fluid exchange - trophallaxis - between adults, and between adults and larvae. Although trophallaxis is widely considered a food-sharing mechanism, we hypothesized that endogenous components of this fluid might underlie a novel means of chemical communication between colony members. Through protein and small-molecule mass spectrometry and RNA sequencing, we found that trophallactic fluid in the ant Camponotus floridanus contains a set of specific digestion- and non-digestion related proteins, as well as hydrocarbons, microRNAs, and a key developmental regulator, juvenile hormone. When C. floridanus workers' food was supplemented with this hormone, the larvae they reared via trophallaxis were twice as likely to complete metamorphosis and became larger workers. Comparison of trophallactic fluid proteins across social insect species revealed that many are regulators of growth, development and behavioral maturation. These results suggest that trophallaxis plays previously unsuspected roles in communication and enables communal control of colony phenotypes

Drug-to-Antibody Ratio Estimation via Proteoform Peak Integration in the Analysis of Antibody-Oligonucleotide Conjugates with Orbitrap Fourier Transform Mass Spectrometry

The therapeutic efficacy and pharmacokinetics of antibody-drug conjugates (ADCs) in general, and antibody-oligonucleotide conjugates (AOCs) in particular, depend on the drug-to-antibody ratio (DAR) distribution and average value. The DAR is considered a critical quality attribute, and information pertaining to it needs to be gathered during ADC/AOC development, production, and storage. However, because of the high structural complexity of ADC/AOC samples, particularly in the initial drug-development stages, the application of the current state-of-the-art mass spectrometric approaches can be limited for DAR analysis. Here, we demonstrate a novel approach for the analysis of complex ADC/AOC samples, following native size-exclusion chromatography Orbitrap Fourier transform mass spectrometry (FTMS). The approach is based on the integration of the proteoform-level mass spectral peaks in order to provide an estimate of the DAR distribution and its average value with less than 10% error. The peak integration is performed via a truncation of the Orbitrap's unreduced time-domain ion signals (transients) before mass spectra generation via FT processing. Transient recording and processing are undertaken using an external data acquisition system, FTMS Booster X2, coupled to a Q Exactive HF Orbitrap FTMS instrument. This approach has been applied to the analysis of whole and subunit-level trastuzumab conjugates with oligonucleotides. The obtained results indicate that ADC/AOC sample purification or simplification procedures, for example, deglycosylation, could be omitted or minimized prior to the DAR analysis, streamlining the drug-development process

Anti-microbial peptides: from invertebrates to vertebrates

International audienc

A post-modification approach to peptide foldamers

Hydrophilic/hydrophobic patterning is a powerful strategy to control folding in non-natural polymers/oligomers. In this contribution, we present a novel strategy for the preparation of alternating hydrophilic/hydrophobic patterned non-natural peptide foldamers. This strategy relies on the post-modification of a reactive peptide precursor that can be prepared via standard solid phase peptide synthesis without the need for side chain protective groups. The peptide scaffolds consisted of an alternating sequence of L-leucine and L-allylglycine residues. Using thiol-ene chemistry, the double bonds in the side chains of the L-allylglycine units could be post-modified with cysteamine hydrochloride, thioglycolic acid, 1-thioglycerol or 2,3,4,6-tetra-O-acetyl-thio-beta-D-glucopyranose to afford alternating hydrophilic/hydrophobic patterned peptides. In agreement with the alternating hydrophilic/hydrophobic patterned primary structure, cysteamine and thioglycolic acid post-modified octapeptides were found to adopt a beta-sheet secondary structure in basic or acidic aqueous media, respectively. The proposed synthetic approach is not only of interest to generate diverse libraries of peptide foldamers from a limited number of reactive precursor scaffolds, but may also represent an attractive, general strategy for the synthesis of peptides with complex side chain functionalities that are not easily accessible via standard solid phase techniques