Thiophenyl Derivatives of Nicotinamide Are Metabolized by the NAD Salvage Pathway into Unnatural NAD Derivatives That Inhibit IMPDH and Are Toxic to Peripheral Nerve Cancers.

N-Pyridinylthiophene carboxamide (compound 21) displays activity against peripheral nerve sheath cancer cells and mouse xenografts by an unknown mechanism. Through medicinal chemistry, we identified a more active derivative, compound , and found that only analogues with structures similar to nicotinamide retained activity. Genetic screens using compound found that both NAMPT and NMNAT1, enzymes in the NAD salvage pathway, are necessary for activity.

Discovery and Optimization of N-Arylated Tetracyclic Dicarboximides That Target Primary Glioma Stem-like Cells.

We recently discovered a novel N-aryl tetracyclic dicarboximide MM0299 () with robust activity against glioma stem-like cells that potently and selectively inhibits lanosterol synthase leading to the accumulation of the toxic shunt metabolite 24(),25-epoxycholesterol. Herein, we delineate a systematic and comprehensive SAR study that explores the structural space surrounding the N-aryl tetracyclic dicarboximide scaffold. A series of 100 analogs were synthesized and evaluated for activity against the murine glioma stem-like cell line Mut6 and for metabolic stability in mouse liver S9 fractions.

Novel orexin receptor agonists based on arene- or pyridine-fused 1,3-dihydro-2H-imidazole-2-imines.

A structurally novel class of benzo- or pyrido-fused 1,3-dihydro-2H-imidazole-2-imines was designed and evaluated in an inositol phosphate accumulation assay for G signaling to measure agonistic activation of the orexin receptor type 2 (OXR). These compounds were synthesized in 4-9 steps overall from readily available starting materials. Analogs that contain a stereogenic methyl or cyclopropyl substituent at the benzylic center, and a correctly configured alkyl ether, alkoxyalkyl ether, cyanoalkyl ether, or α-hydroxyacetamido substituted homobenzylic sidechain were identified as the most potent activators of OXR coupled G signaling.

Anticancer benzoxaboroles block pre-mRNA processing by directly inhibiting CPSF3.

A novel class of benzoxaboroles was reported to induce cancer cell death but the mechanism was unknown. Using a forward genetics platform, we discovered mutations in cleavage and polyadenylation specific factor 3 (CPSF3) that reduce benzoxaborole binding and confer resistance. CPSF3 is the endonuclease responsible for pre-mRNA 3'-end processing, which is also important for RNA polymerase II transcription termination.

Structural insights for selective disruption of Beclin 1 binding to Bcl-2.

Stimulation of autophagy could provide powerful therapies for multiple diseases, including cancer and neurodegeneration. An attractive drug target for this purpose is Bcl-2, which inhibits autophagy by binding to the Beclin 1 BH3-domain. However, compounds that preclude Beclin 1/Bcl-2 binding might also induce apoptosis, which is inhibited by binding of Bcl-2 to BH3-domains of pro-apoptosis factors such as Bax.

Inducible mismatch repair streamlines forward genetic approaches to target identification of cytotoxic small molecules.

Orphan cytotoxins are small molecules for which the mechanism of action (MoA) is either unknown or ambiguous. Unveiling the mechanism of these compounds may lead to useful tools for biological investigation and new therapeutic leads. In selected cases, the DNA mismatch repair-deficient colorectal cancer cell line, HCT116, has been used as a tool in forward genetic screens to identify compound-resistant mutations, which have ultimately led to target identification.

Inducible mismatch repair streamlines forward genetic approaches to target identification of cytotoxic small molecules.

Orphan cytotoxins are small molecules for which the mechanism of action (MoA) is either unknown or ambiguous. Unveiling the mechanism of these compounds may lead to useful tools for biological investigation and in some cases, new therapeutic leads. In select cases, the DNA mismatch repair-deficient colorectal cancer cell line, HCT116, has been used as a tool in forward genetic screens to identify compound-resistant mutations, which have ultimately led to target identification.

Evaluation of the efficacy of the hypocretin/orexin receptor agonists TAK-925 and ARN-776 in narcoleptic orexin/tTA; TetO-DTA mice.

The sleep disorder narcolepsy, a hypocretin deficiency disorder thought to be due to degeneration of hypothalamic hypocretin/orexin neurons, is currently treated symptomatically. We evaluated the efficacy of two small molecule hypocretin/orexin receptor-2 (HCRTR2) agonists in narcoleptic male orexin/tTA; TetO-DTA mice. TAK-925 (1-10 mg/kg, s.

Selective and brain-penetrant lanosterol synthase inhibitors target glioma stem-like cells by inducing 24(S),25-epoxycholesterol production.

Glioblastoma (GBM) is an aggressive adult brain cancer with few treatment options due in part to the challenges of identifying brain-penetrant drugs. Here, we investigated the mechanism of MM0299, a tetracyclic dicarboximide with anti-glioblastoma activity. MM0299 inhibits lanosterol synthase (LSS) and diverts sterol flux away from cholesterol into a "shunt" pathway that culminates in 24(S),25-epoxycholesterol (EPC).

Novel Bcl-2 Inhibitors Selectively Disrupt the Autophagy-Specific Bcl-2-Beclin 1 Protein-Protein Interaction.

Autophagy plays essential roles in a wide variety of physiological processes, such as cellular homeostasis, metabolism, development, differentiation, and immunity. Selective pharmacological modulation of autophagy is considered a valuable potential therapeutic approach to treat diverse human diseases. However, development of such therapies has been greatly impeded by the lack of specific small molecule autophagy modulators.

TK216 targets microtubules in Ewing sarcoma cells.

Ewing sarcoma (EWS) is a pediatric malignancy driven by the EWSR1-FLI1 fusion protein formed by the chromosomal translocation t(11; 22). The small molecule TK216 was developed as a first-in-class direct EWSR1-FLI1 inhibitor and is in phase II clinical trials in combination with vincristine for patients with EWS. However, TK216 exhibits anti-cancer activity against cancer cell lines and xenografts that do not express EWSR1-FLI1, and the mechanism underlying cytotoxicity remains unresolved.

A convergent approach toward fidaxomicin: Syntheses of the fully glycosylated northern and southern fragments.

Efficient approaches that enable the synthesis of analogs of natural product antibiotics are needed to keep up with the emergence of multiply-resistant strains of pathogenic organisms. One promising candidate in this area is fidaxomicin, which boasts impressive anti-tubercular activity but has poor systemic bioavailability. We designed a flexible synthetic route to this target to enable the exploration of new chemical space and the future development of analogs with superior pharmacokinetics.

A Multipronged Approach Establishes Covalent Modification of β-Tubulin as the Mode of Action of Benzamide Anti-cancer Toxins.

A phenotypic high-throughput screen identified a benzamide small molecule with activity against small cell lung cancer cells. A "clickable" benzamide probe was designed that irreversibly bound a single 50 kDa cellular protein, identified by mass spectrometry as β-tubulin. Moreover, the anti-cancer potency of a series of benzamide analogs strongly correlated with probe competition, indicating that β-tubulin was the functional target.

The structure of importin α and the nuclear localization peptide of ChREBP, and small compound inhibitors of ChREBP-importin α interactions.

The carbohydrate response element binding protein (ChREBP) is a glucose-responsive transcription factor that plays a critical role in glucose-mediated induction of genes involved in hepatic glycolysis and lipogenesis. In response to fluctuating blood glucose levels ChREBP activity is regulated mainly by nucleocytoplasmic shuttling of ChREBP. Under high glucose ChREBP binds to importin α and importin β and translocates into the nucleus to initiate transcription.

A Medicinal Chemistry-Driven Approach Identified the Sterol Isomerase EBP as the Molecular Target of TASIN Colorectal Cancer Toxins.

TASIN (Truncated APC-Selective Inhibitors) compounds are selectively toxic to colorectal cancer cells with mutations, although their mechanism of action remains unknown. Here, we found that TASINs inhibit three enzymes in the postsqualene cholesterol biosynthetic pathway including EBP, DHCR7, and DHCR24. Even though all three of these enzymes are required for cholesterol biosynthesis, only inhibition of the most upstream enzyme, EBP, led to cancer cell death via depletion of downstream sterols, an observation that was confirmed by genetic silencing of EBP.

Structural basis for itraconazole-mediated NPC1 inhibition.

Niemann-Pick C1 (NPC1), a lysosomal protein of 13 transmembrane helices (TMs) and three lumenal domains, exports low-density-lipoprotein (LDL)-derived cholesterol from lysosomes. TMs 3-7 of NPC1 comprise the Sterol-Sensing Domain (SSD). Previous studies suggest that mutation of the NPC1-SSD or the addition of the anti-fungal drug itraconazole abolishes NPC1 activity in cells.

Design and Synthesis of TASIN Analogues Specifically Targeting Colorectal Cancer Cell Lines with Mutant Adenomatous Polyposis Coli (APC).

Despite advances in targeted anticancer therapies, there are still no small-molecule-based therapies available that specifically target colorectal cancer (CRC) development and progression, the second leading cause of cancer deaths. We previously disclosed the discovery of truncating adenomatous polyposis coli (APC)-selective inhibitor 1 (TASIN-1), a small molecule that specifically targets colorectal cancer cells lines with truncating mutations in the adenomatous polyposis coli (APC) tumor suppressor gene through inhibition of cholesterol biosynthesis. Here, we report a medicinal chemistry evaluation of a collection of TASIN analogues and activity against colon cancer cell lines and an isogenic cell line pair reporting on the status of APC-dependent selectivity.

Isolation, Structure, and Total Synthesis of the Marine Macrolide Mangrolide D.

The isolation, characterization, and total synthesis of the macrocyclic polyene mangrolide D is reported. A 16-step total synthesis relies on robust Suzuki and ring-closing metathesis reactions, and an iron-catalyzed hydroazidation of an exomethylene substituted tetrahydropyran as a key step for the synthesis of the appended 4- epi-vancosamine sugar. Although mangrolide D did not display antibiotic activity, this work should prove enabling toward the synthesis of the antitubercular tiacumicins which display a virtually identical macrocyclic backbone.

Gboxin is an oxidative phosphorylation inhibitor that targets glioblastoma.

Cancer-specific inhibitors that reflect the unique metabolic needs of cancer cells are rare. Here we describe Gboxin, a small molecule that specifically inhibits the growth of primary mouse and human glioblastoma cells but not that of mouse embryonic fibroblasts or neonatal astrocytes. Gboxin rapidly and irreversibly compromises oxygen consumption in glioblastoma cells.

A biosynthetically inspired synthesis of (-)-berkelic acid and analogs.

We describe a complete account of our total synthesis and biological evaluation of (-)-berkelic acid and analogs. We delineate a synthetic strategy inspired by a potentially biomimetic union between the natural products spicifernin and pulvilloric acid. After defining optimal parameters, we executed a one-pot silver-mediated in situ dehydration of an isochroman lactol to methyl pulvillorate, the cycloisomerization of a spicifernin-like alkynol to the corresponding exocyclic enol ether, and a subsequent cycloaddition to deliver the tetracyclic core of berkelic acid.

Species-Selective Pyrimidineamine Inhibitors of Trypanosoma brucei S-Adenosylmethionine Decarboxylase.

New therapeutic options are needed for treatment of human African trypanosomiasis (HAT) caused by protozoan parasite Trypanosoma brucei. S-Adenosylmethionine decarboxylase (AdoMetDC) is an essential enzyme in the polyamine pathway of T. brucei.

Antiviral Properties of Chemical Inhibitors of Cellular Anti-Apoptotic Bcl-2 Proteins.

Viral diseases remain serious threats to public health because of the shortage of effective means of control. To combat the surge of viral diseases, new treatments are urgently needed. Here we show that small-molecules, which inhibit cellular anti-apoptotic Bcl-2 proteins (Bcl-2i), induced the premature death of cells infected with different RNA or DNA viruses, whereas, at the same concentrations, no toxicity was observed in mock-infected cells.