Muhammad Ayaz

General One-pot, Two-Step Protocol Accessing a Range of Novel Polycyclic Heterocycles with High Skeletal Diversity

An Ugi one-pot three-component four-center reaction was coupled with a subsequent acid mediated cyclodehydration step to furnish a multitude of unique scaffolds having in common an embedded or attached benzimidazole and often a ring system formed through lactamization. Using combinations of tethered Ugi inputs typically via tethered acid-ketone inputs and supporting reagents containing masked internal nucleophiles, such scaffolds were produced in good to excellent yields in an operationally friendly manner.

Synthesis of diverse nitrogen-enriched heterocyclic scaffolds using a suite of tunable one-pot multicomponent reactions.

Five elegant and switchable three-component reactions which enable access to a new series of nitrogen-containing heterocycles are reported. A novel one-step addition of an isocyanide to a hydrazine derived Schiff base affords unique six-membered pyridotriazine scaffolds (A and E). With slight modification of reaction conditions and replacement of the nucleophilic isocyanide moiety with different electrophiles (i.e., isocyanates, isothiocyanates, cyclic anhydrides, and acyl chlorides) five-membered triazolopyridine scaffolds (B, D, F, G) are generated in a single step. Furthermore, the use of phenyl hydrazine enables access to dihydroindazole-carboxamides, devoid of a bridge-head nitrogen (C). All protocols are robust and tolerate a diverse collection of reactants, and as such, it is expected that the new scaffolds and associated chemistry will garner high interest from medicinal chemists involved in either file enhancement or specific target-related drug discovery campaigns.

The Synthesis of Stable, Complex Organocesium Tetramic Acids through the Ugi Reaction and Cesium-Carbonate-Promoted Cascades

Two structurally unique organocesium carbanionic tetramic acids have been synthesized through expeditious and novel cascade reactions of strategically functionalized Ugi skeletons delivering products with two points of potential diversification. This is the first report of the use of multicomponent reactions and subsequent cascades to access complex, unprecedented organocesium architectures. Moreover, this article also highlights the first use of mild cesium carbonate as a cesium source for the construction of cesium organometallic scaffolds. Relativistic DFT calculations provide an insight into the electronic structure of the reported compounds.

Potent Dual BET Bromodomain-Kinase Inhibitors as Value-Added Multitargeted Chemical Probes and Cancer Therapeutics.

Synergistic action of kinase and BET bromodomain inhibitors in cell killing has been reported for a variety of cancers. Using the chemical scaffold of the JAK2 inhibitor TG101348, we developed and characterized single agents which potently and simultaneously inhibit BRD4 and a specific set of oncogenic tyrosine kinases including JAK2, FLT3, RET, and ROS1. Lead compounds showed on-target inhibition in several blood cancer cell lines and were highly efficacious at inhibiting the growth of hematopoietic progenitor cells from patients with myeloproliferative neoplasm. Screening across 931 cancer cell lines revealed differential growth inhibitory potential with highest activity against bone and blood cancers and greatly enhanced activity over the single BET inhibitor JQ1. Gene drug sensitivity analyses and drug combination studies indicate synergism of BRD4 and kinase inhibition as a plausible reason for the superior potency in cell killing. Combined, our findings indicate promising potential of these agents as novel chemical probes and cancer therapeutics. Mol Cancer Ther; 16(6); 1054–67. ©2017 AACR.

A simple one-pot 2-step N-1-alkylation of indoles with α-iminoketones toward the expeditious 3-step synthesis of N-1-quinoxaline-indoles

A straightforward procedure for the preparation of N-quinoxaline-indoles is presented. A base-catalyzed one-pot addition of indoles to a preformed α-iminoketone proceeds on the N-1 indole and the subsequent adduct undergoes an acid-mediated deprotection of an internal amino nucleophile, intramolecular cyclization and final oxidation generating N-1-quinoxaline-indoles in good yield.

Ligand-mediated protein degradation reveals functional conservation among sequence variants of the CUL4-type E3 ligase substrate receptor cereblon

Upon binding to thalidomide and other immunomodulatory drugs, the E3 ligase substrate receptor cereblon (CRBN) promotes proteosomal destruction by engaging the DDB1–CUL4A–Roc1–RBX1 E3 ubiquitin ligase in human cells but not in mouse cells, suggesting that sequence variations in CRBN may cause its inactivation. Therapeutically, CRBN engagers have the potential for broad applications in cancer and immune therapy by specifically reducing protein expression through targeted ubiquitin-mediated degradation. To examine the effects of defined sequence changes on CRBNs activity, we performed a comprehensive study using complementary theoretical, biophysical, and biological assays aimed at understanding CRBNs nonprimate sequence variations. With a series of recombinant thalidomide-binding domain (TBD) proteins, we show that CRBN sequence variants retain their drug-binding properties to both classical immunomodulatory drugs and dBET1, a chemical compound and targeting ligand designed to degrade bromodomain-containing 4 (BRD4) via a CRBN-dependent mechanism. We further show that dBET1 stimulates CRBNs E3 ubiquitin–conjugating function and degrades BRD4 in both mouse and human cells. This insight paves the way for studies of CRBN-dependent proteasome-targeting molecules in nonprimate models and provides a new understanding of CRBNs substrate-recruiting function.

Abstract 221: Integrated functional proteomics of MET/VEGFR inhibitors reveals complex mechanism of action of foretinib in NSCLC

BACKGROUND: Foretinib (FORE) and cabozantinib (CABO) are two MET/VEGFR inhibitors with similar chemical structures. CABO is FDA-approved for medullary thyroid and renal cancer; in addition, it is in clinical trials for treatment of non-small cell lung cancer (NSCLC). Through an unbiased viability screen we have observed potent cellular activity of FORE, but not CABO, in several NSCLC cell lines. We have previously shown that most NSCLC cell lines are insensitive to MET or VEGFR inhibition, suggesting off-target activity of FORE in these cells. The aim of this project is to identify the mechanism of action of FORE in NSCLC and design an optimized combination therapy. METHODS: Cellular viability assays were done using CellTiter-Glo, cell cycle analysis by flow cytometry. Western blotting was performed to evaluate the induction of apoptosis through PARP1 and caspase cleavage, as well changes in signaling. We synthesized FORE and CABO analogues and performed differential quantitative chemical and phosphoproteomics to determine the target kinase profile and pathway effects in NSCLC cells. Changes in gene expression upon drug treatment were measured by RNA-seq. RNAi in combination with pharmacological inhibitors was performed to interrogate targets and pathways. RESULTS: FORE showed greater potency in NSCLC cell lines than CABO with regard to inhibition of viability and induction of apoptosis. FORE decreased phosphorylation of AKT and ERK. Chemical and phosphoproteomics revealed several kinases, such as MEK and MAP4K5, to bind preferentially by FORE over CABO that differentially affect the adherens junction and MAPK signaling pathways. Target validation showed differential inhibition of MEK1/2 and MAP4K5. Cellular validation with RNAi in combination with pharmacological inhibitors suggested that MEK1/2, MAP4K5 and IGF1R are involved in the mechanism of action of foretinib in NSCLC cells. RNA-seq pathway analysis furthermore suggested regulation of chromatin organization and Wnt pathway signaling by foretinib. CONCLUSION: Our results suggest that the difference in the efficacy between FORE and CABO is related to polypharmacology of FORE, which simultaneously targets IGF1R, MEK1/2 and MAP4K5. This difference results in divergence in signaling pathway inhibition and induces distinct effects in NSCLC. The establishment of FORE targets and signaling pathways can lead to optimized combination therapy for NSCLC and identification of new actionable kinases in lung cancer cells. Citation Format: Natalia J. Sumi, Bin Fang, Lily L. Rix, Muhammad Ayaz, Fumi Kinose, Eric A. Welsh, Steven A. Eschrich, Harshani R. Lawrence, John M. Koomen, Eric B. Haura, Uwe Rix. Integrated functional proteomics of MET/VEGFR inhibitors reveals complex mechanism of action of foretinib in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 221. doi:10.1158/1538-7445.AM2017-221