Fabienne Z. Gaugaz

Bio: Fabienne Z. Gaugaz is an academic researcher from ETH Zurich. The author has contributed to research in topics: Epothilones & Switched capacitor. The author has an hindex of 3, co-authored 7 publications receiving 51 citations. Previous affiliations of Fabienne Z. Gaugaz include École Polytechnique Fédérale de Lausanne.

Diversity through semisynthesis: the chemistry and biological activity of semisynthetic epothilone derivatives

Abstract: Epothilones are myxobacterial natural products that inhibit human cancer cell growth through the stabil- ization of cellular microtubules (i.e., a "taxol-like" mech- anism of action). They have proven to be highly productive lead structures for anticancer drug discovery, with at least seven epothilone-type agents having entered clinical trials in humans over the last several years. SAR studies on epothil- ones have included a large number of fully synthetic ana- logs and semisynthetic derivatives. Previous reviews on the chemistryandbiologyofepothiloneshavemostlyfocusedon analogs thatwereobtainedbydenovochemical synthesis.In contrast, the current review provides a comprehensive over- view on the chemical transformations that have been investi- gatedforthemajorepothilonesAandBasstartingmaterials, and it discusses the biological activity of the resulting prod- ucts. Many semisynthetic epothilone derivatives have been found to exhibit potent effects on human cancer cell growth and several of these have been advanced to the stage of clini-

The Impact of Cyclopropane Configuration on the Biological Activity of Cyclopropyl‐Epothilones

Abstract: Two cis-12,13-cyclopropyl-epothilone B variants have been synthesized, differing only in the configuration of the stereocenters at C12 and C13. The syntheses were based on a common allylic alcohol intermediate that was converted into the corresponding diastereomeric hydroxymethyl-cyclopropanes by means of stereoselective Charette cyclopropanations. Macrocyclizations were accomplished through ring-closing metathesis (RCM). Substantial differences between the two compounds were found with regard to microtubule binding affinity, antiproliferative activity and their effects on the cellular microtubule network. While the analogue with the cyclopropane moiety oriented in a corresponding way to the epoxide configuration in natural epothilones was almost equipotent with epothilone A, the other was significantly less active. Based on these findings, natural epothilone-like activity of cis-fused 12,13-cyclopropyl-epothilone analogues is tightly linked to the natural orientation of the cyclopropane moiety.

Chapter 16:Epothilones as Lead Structures for New Anticancer Drugs

Abstract: Drugs targeting cellular microtubules are an important element of our clinical armamentarium for cancer therapy,1 with applications in the treatment of a variety of cancer types, either as single agents or as part of different combination regimens.2,3 Microtubule-interacting agents can be grouped in...

Synthesis, Microtubule-Binding Affinity, and Antiproliferative Activity of New Epothilone Analogs and of an EGFR-Targeted Epothilone-Peptide Conjugate

Abstract: A new simplified, epoxide-free epothilone analog was prepared incorporating an N-(2-hydroxyethyl)-benzimidazole side chain, which binds to microtubules with high affinity and inhibits cancer cell growth in vitro with nM potency. Building on this scaffold, a disulfide-linked conjugate with the purported EGFR-binding (EGFR, epidermal growth factor receptor) peptide GE11 was then prepared. The conjugate retained significant microtubule-binding affinity, in spite of the size of the peptide attached to the benzimidazole side chain. The antiproliferative activity of the conjugate was significantly lower than for the parent scaffold and, surprisingly, was independent of the EGFR expression status of cells. Our data indicate that the disulfide-based conjugation with the GE11 peptide is not a viable approach for effective tumor-targeting of highly potent epothilones and probably not for other cytotoxics.

Modulators of Protein-Protein Interactions

Abstract: Lech-Gustav Milroy,† Tom N. Grossmann,‡,§ Sven Hennig,‡ Luc Brunsveld,† and Christian Ottmann*,† †Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands ‡Chemical Genomics Centre of the Max Planck Society, Otto-Hahn Straße 15, 44227 Dortmund, Germany Department of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany

Design and synthesis of analogues of natural products

Abstract: In this article strategies for the design and synthesis of natural product analogues are summarized and illustrated with some selected examples. Proven strategies include diverted total synthesis (DTS), function-oriented synthesis (FOS), biology-oriented synthesis (BIOS), complexity to diversity (CtD), hybrid molecules, and biosynthesis inspired synthesis. The latter includes mutasynthesis, the synthesis of natural products encoded by silent genes, and propionate scanning. Most of the examples from our group fall in the quite general concept of DTS. Thus, in case an efficient strategy to a natural product is at hand, modifications are possible at almost any stage of a synthesis. However, even for compounds of moderate complexity, organic synthesis remains a bottle neck. Unless some method for predicting the biological activity of a designed molecule becomes available, the design and synthesis of natural product analogues will remain what it is now, namely it will largely rely on trial and error.

Dark chemical matter as a promising starting point for drug lead discovery

Abstract: High-throughput screening (HTS) is an integral part of early drug discovery. Herein, we focused on those small molecules in a screening collection that have never shown biological activity despite having been exhaustively tested in HTS assays. These compounds are referred to as 'dark chemical matter' (DCM). We quantified DCM, validated it in quality control experiments, described its physicochemical properties and mapped it into chemical space. Through analysis of prospective reporter-gene assay, gene expression and yeast chemogenomics experiments, we evaluated the potential of DCM to show biological activity in future screens. We demonstrated that, despite the apparent lack of activity, occasionally these compounds can result in potent hits with unique activity and clean safety profiles, which makes them valuable starting points for lead optimization efforts. Among the identified DCM hits was a new antifungal chemotype with strong activity against the pathogen Cryptococcus neoformans but little activity at targets relevant to human safety.