Simon J. Shaw

Structural requirements for VanA activity of vancomycin analogues

We have prepared several sets of glycopeptide analogues in order to probe the molecular basis for the activity of derivatives that overcome vanA resistance. The results described in this paper provide compelling evidence that good vanA activity is due to a mechanism of action that does not involve peptide binding. Hypothesizing that this mechanism of action involves an interaction of the disaccharide portion of vancomycin analogues with bacterial transglycosylases, we have prepared a compound in which the vancomycin aglycone is coupled to a known transglycosylase inhibitor that is structurally unrelated to the disaccharides that have been previously investigated. The activity of this compound is excellent. This work provides a clear prescription for the design of better glycopeptide analogues.

Developing structure-activity relationships from an HTS hit for inhibition of the Cks1-Skp2 protein-protein interaction.

Structure-activity relationships have been developed around 5-bromo-8-toluylsulfonamidoquinoline 1 a hit compound in an assay for the interaction of the E3 ligase Skp2 with Cks1, part of the SCF ligase complex. Disruption of this protein-protein interaction results in higher levels of CDK inhibitor p27, which can act as a tumor suppressor. The results of the SAR developed highlight the relationship between the sulfonamide and quinoline nitrogen, while also suggesting that an aryl substituent at the 5-position of the quinoline ring contributes to the potency in the interaction assay. Compounds showing potency in the interaction assay result in greater levels of p27 and have been shown to inhibit cell growth of two p27 sensitive tumor cell lines.

Coumarin-derived discodermolide analogues possessing equivalent antiproliferative activity to the natural product--a further simplification of the lactone region.

Analogues of discodermolide in which the complete C-1 to C-7 fragment is replaced with a coumarin moiety display equivalent potency to that of the natural product.

Structure−Activity Relationships of 9-Substituted-9-Dihydroerythromycin-Based Motilin Agonists: Optimizing for Potency and Safety

A series of 9-dihydro-9-acetamido-N-desmethyl-N-isopropyl erythromycin A analogues and related derivatives was generated as motilin agonists. The compounds were optimized for potency while showing both minimal antibacterial activity and hERG inhibition. As the substituent on the amide was increased in lipophilicity the potency and hERG inhibition increased, while polar groups lowered potency, without significantly impacting hERG inhibition. The N-methyl acetamide 7a showed the optimal in vitro profile and was probed further by varying the chain length to the macrocycle as well as changing the macrocycle scaffold. 7a remained the compound with the best in vitro properties.

9-Dihydroerythromycin ethers as motilin agonists--developing structure-activity relationships for potency and safety.

A series of derivatives of the amine of 9-dihydro-9-O-ethylamino-N-desmethyl-N-isopropyl erythromycin A derivatives were synthesized as motilin agonists. The compounds were developed for potency without showing antibacterial activity and inhibition of the hERG potassium channel. The formamide of the amide series was found to show the optimal combination of properties relative to carbamates, ureas, thioureas, and amines. This prompted an investigation of heterocyclic isosteres for the amide. In this series the triazole had the optimal combination of properties. From the study, two compounds met the criteria for detailed pharmacokinetic studies.

Fragment Assembly: An Alternative Approach to Generating Complex Polyketides

Abstract A new approach to the preparation of complex polyketide natural products has been outlined in which the products of biosynthesis are used as starting materials for chemical synthesis of difficult‐to‐obtain natural products.

Ring-Opening of Benzocyclobutenol with Mild Bases and Trapping with Dieneophiles

Abstract The treatment of benzocyclobutenol with a mild base has been investigated. This reaction results in an electrocyclic opening of the cyclobutene to the corresponding o‐quinodimethane, which has been successfully treated with aldehydes and electron‐deficient alkenes to form benzolactols and benzocyclohexenes respectively.

Investigating Carboxylic Acid Analogues of Ambruticin through Semi‐Synthesis

Systemic fungal infections have increased significantly in recent years, principally in immunocompromised patients. This is particularly an issue for those with HIV/AIDS and patients undergoing cancer or organ transplant therapy. There are only a small number of drugs available to treat such infections including Amphotericin B, which has considerable side effects. Therefore, new antifungal agents are needed. The polyketide antifungal antibiotic ambruticin was first isolated in the late 1970s by Warner-Lambert from the myxobacteria Polyangium cellulosum var. flavum. The molecule comes in two series characterised by the functional group found at the 5-position (ambruticin numbering, see Figure 1); the S

Developing DYRK inhibitors derived from the meridianins as a means of increasing levels of NFAT in the nucleus

A structure-activity relationship has been developed around the meridianin scaffold for inhibition of Dyrk1a. The compounds have been focussed on the inhibition of kinase Dyrk1a, as a means to retain the transcription factor NFAT in the nucleus. NFAT is responsible for up-regulation of genes responsible for the induction of a slow, oxidative skeletal muscle phenotype, which may be an effective treatment for diseases where exercise capacity is compromised. The SAR showed that while strong Dyrk1a binding was possible with the meridianin scaffold the compounds have no effect on NFAT localisation, however, by moving from the indole to a 6-azaindole scaffold both potent Dyrk1a binding and increased NFAT residence time in the nucleus were obtained - properties not observed with the reported Dyrk1a inhibitors. One compound was shown to be effective in an ex vivo muscle fiber assay. The increased biological activity is thought to arise from the added interaction between the azaindole nitrogen and the lysine residue in the back pocket.

Abstract 3021: Development of small molecule direct AMPK activators for the treatment of cancer

5’-AMP-activated protein kinase (AMPK) is a key sensor of cellular energy status and is critical for maintaining energy homeostasis under conditions of nutrient stress. During cellular transformation, metabolic reprogramming enables the aberrant growth and proliferation of tumor cells. Both positive and negative roles for AMPK in tumor cell proliferation and survival have been reported. However, only a limited number of studies addressed this question with potent direct AMPK activators. AMPK exists as heterotrimers composed of the catalytic subunit α and reguratory subunits β and γ. We expressed the full length of all three human AMPK subunits in insect cells, purified the heterotrimer complexes, and used them for biochemical screening and characterization of AMPK activators. The purified complexes displayed basal activity, which was further enhanced by AMP. The compounds we identified potently activated the complexes in vitro at AC(2X)s (the concentration that gives a twofold activation) of 0.001-0.3 μM. Importantly, the compounds up-regulated substrate phosphorylation (pS79 Acetyl-CoA Carboxylase) and/or auto-phosphorylation (pT172 AMPKα) in multiple cancer cell lines including HepG2 hepatoma cells, A549 liver kinase B1 (LKB1) null lung cancer cells, and MOLM14 myeloid leukemia cells, indicating activation was irrespective of functional status of LKB1, which is a key AMPK-activation kinase. Activation of AMPK by the compounds was also confirmed using native AMPK isolated from normal tissues and tumor cells. We further investigated anti-proliferative effects of the compounds and found that up-regulation of AMPK kinase activity was correlated with anti-proliferative effects in A549 and MOLM14, but not in HepG2, suggesting that positive effects of direct AMPK activators could be cell-type dependent. Interestingly, we identified compounds that display comparable AMPK activation in HepG2 and A549 yet possessed divergent activities on proliferation across a panel of tumor lines. Analysis of cellular signaling across several of these tumor lines with this set of the compounds revealed dose-dependent effects on mTORC1 substrates, feedback signaling to PI3K and mTORC2, and inhibition of kinases downstream of RAF. Direct activation of AMPK could be a good therapeutic strategy for the treatment of subsets of cancers. Citation Format: Yasumichi Hitoshi, Yonchu Jenkins, Yingwu Li, Elmer Sampang, Xiang Xu, Guodong Dong, Jianing Huang, Nan Lin, Dane Goff, Simon Shaw, Luke Boralsky, Rajinder Singh, Sarkiz D. Issakani, Donald G. Payan. Development of small molecule direct AMPK activators for the treatment of cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3021.