Second-generation Analogues Research Articles

Identification of pyrimidine structure-based compounds as allosteric ligands of the dopamine transporter as therapeutic agents for NeuroHIV.

The disruption of dopamine neurotransmission by the HIV-1 Transactivator of transcription (Tat) during HIV-1 infection has been linked to the development of neurocognitive disorders, even under combined antiretroviral therapy (cART) treatment. We have demonstrated that SRI-32742, a novel allosteric modulator of dopamine (DA) transporter (DAT), attenuates cocaine- and Tat-binding to DAT, alleviates Tat-induced cognitive deficits and potentiation of cocaine reward in inducible Tat transgenic mice. The current study determined the in vitro pharmacological profile of SRI-32743 and its optimized second-generation analogs and their effects as allosteric modulators. Through structure-activity relationship studies of SRI-32743, 170 compounds were synthesized and evaluated for their ability to modulate DAT function. We identified 21 analogs as atypical competitors of DAT (Emax {less than or equal to}60%). Four compounds, SRI-46564, SRI-47056, SRI-46286 and SRI-47867, displayed IC50 values for [3H]DA uptake inhibition from 9.33 {plus minus} 0.50 to 0.96 {plus minus} 0.05 µM and from 3.96 {plus minus} 1.36 to 1.29 {plus minus} 0.19 for DAT binding, respectively. The four analogs also displayed high potency at two different concentrations (0.5 nM and 0.05 nM) to attenuate Tat-induced inhibition of [3H]DA uptake and cocaine-mediated dissociation of [3H]WIN35,428 binding in CHO cells expressing hDAT, suggesting that the effects occur through an allosteric mechanism. In further ex vivo studies using Fast-Scan Cyclic Voltammetry, we demonstrated that the analogs do not disrupt the baseline phasic-like DA release. These findings provide a new insight into the potential for development of novel therapeutic agents to attenuate DAT-Tat interactions to normalize DA neurotransmission in NeuroHIV. Significance Statement The allosteric inhibition of the dopamine (DA) transporter by the HIV-1 Transactivator of transcription (Tat) disrupts dopamine homeostasis, leading to HIV-associated neurocognitive disorders (HANDs). Analogs of SRI-32743, a novel allosteric modulator of the Tat-DAT interaction, were evaluated in the current study and characterized as atypical ligands of DA uptake. Four novel lead compounds demonstrated high potency to attenuate Tat-induced inhibition of hDAT-mediated DA uptake in an allosteric modulatory manner with no effects on the dynamics of DA uptake-release in DAT.

Synthesis of Second-Generation Analogs of Temporin-SHa Peptide Having Broad-Spectrum Antibacterial and Anticancer Effects.

Antimicrobial peptides (AMPs) are a promising class of therapeutic alternatives with broad-spectrum activity against resistant pathogens. Small AMPs like temporin-SHa (1) and its first-generation analog [G10a]-SHa (2) possess notable efficacy against Gram-positive and Gram-negative bacteria. In an effort to further improve this antimicrobial activity, second-generation analogs of 1 were synthesised by replacing the natural glycine residue at position-10 of the parent molecule with atypical amino acids, such as D-Phenylalanine, D-Tyrosine and (2-Naphthyl)-D-alanine, to study the effect of hydrophobicity on antimicrobial efficacy. The resultant analogs (3-6) emerged as broad-spectrum antibacterial agents. Notably, the [G10K]-SHa analog (4), having a lysine substitution, demonstrated a 4-fold increase in activity against Gram-negative (Enterobacter cloacae DSM 30054) and Gram-positive (Enterococcus faecalis DSM 2570) bacteria relative to the parent peptide (1). Among all analogs, [G10f]-SHa peptide (3), featuring a D-Phe substitution, showed the most potent anticancer activity against lung cancer (A549), skin cancer (MNT-1), prostate cancer (PC-3), pancreatic cancer (MiaPaCa-2) and breast cancer (MCF-7) cells, achieving an IC50 value in the range of 3.6-6.8 µM; however, it was also found to be cytotoxic against normal cell lines as compared to [G10K]-SHa (4). Peptide 4 also possessed good anticancer activity but was found to be less cytotoxic against normal cell lines as compared to 1 and 3. These findings underscore the potential of second-generation temporin-SHa analogs, especially analog 4, as promising leads to develop new broad-spectrum antibacterial and anticancer agents.

Biological Evaluation of Dinuclear Platinum(II) Complexes with Aromatic N-Heterocycles as Bridging Ligands.

The history of effective anti-cancer medications begins with the discovery of cisplatin's anti-cancer properties. Second-generation analogue, carboplatin, with a similar range of effectiveness, made progress in improving these drugs with fewer side effects and better solubility. Renewed interest in platinum-based drugs has been increasing in the past several years. These developments highlight a revitalized enthusiasm and ongoing exploration in platinum chemotherapy based on the series of dinuclear platinum(II) complexes, [{Pt(L)Cl}2(μ-bridging ligand)]2+, which have been synthesized and evaluated for their biological activities. These complexes are designed to target various cancerous conditions, exhibiting promising antitumor, antiproliferative, and apoptosis-inducing activities. The current work aims to shed light on the potential of these complexes as next-generation platinum-based therapies, highlighting their enhanced efficacy and reduced side effects, which could revolutionize the approach to chemotherapy.

Human papillomavirus-16 E6-positive cervical cancer attenuated by potent 2-(4-biphenylyl)-N-(1-ethyl-4-piperidinyl) acetamide second-generation analogs with improved binding affinity.

Human papillomavirus (HPV) infection, particularly HPV16, is a major contributor to the development of cervical cancer. Given the urgent need for novel therapeutic strategies targeting HPV-associated cancers, this study focuses on characterizing second-generation analogs of a lead compound, as a potential inhibitor of HPV16-E6. Protein-ligand docking, Gibbs binding free energy estimation, and molecular dynamics simulations were conducted. HPV16-infected SiHa and CaSki cell lines were used. MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay for proliferation and flow cytometry for target inhibition and apoptosis were employed. Computational and cell proliferation analyses revealed that modifications to E6-855, particularly in the piperidinyl group, enhanced binding affinities against HPV16-E6, with E6-272 demonstrating superior binding properties. Molecular dynamics simulations confirmed the stable binding of E6-272 to HPV16-E6, supported by favorable binding energy estimates. E6-272 inhibited the proliferation of SiHa and CaSki cells with GI50 values of 32.56 and 62.09nM, respectively. The compound reduced HPV16-E6-positive population, while inducing the early and late phase apoptosis in these cells. Structural alterations at the piperidinyl group of E6-855 identified E6-272 as a promising inhibitor of HPV16-E6 with improved efficacy against HPV16-E6. Further experimental validation of E6-272 and its analogs warrant to advance its clinical utility in combating HPV-associated cancers.

Inhibition of CREB Binding and Function with a Dual-Targeting Ligand.

CBP/p300 is a master transcriptional coactivator that regulates gene activation by interacting with multiple transcriptional activators. Dysregulation of protein-protein interactions (PPIs) between the CBP/p300 KIX domain and its activators is implicated in a number of cancers, including breast, leukemia, and colorectal cancer. However, KIX is typically considered "undruggable" because of its shallow binding surfaces lacking both significant topology and promiscuous binding profiles. We previously reported a dual-targeting peptide (MybLL-tide) that inhibits the KIX-Myb interaction with excellent specificity and potency. Here, we demonstrate a branched, second-generation analogue, CREBLL-tide, that inhibits the KIX-CREB PPI with higher potency and selectivity. Additionally, the best of these CREBLL-tide analogues shows excellent and selective antiproliferation activity in breast cancer cells. These results indicate that CREBLL-tide is an effective tool for assessing the role of KIX-activator interactions in breast cancer and expanding the dual-targeting strategy for inhibiting KIX and other coactivators that contain multiple binding surfaces.

268-OR: Impact of the COVID-Pandemic on Antihyperglycemic Prescription Patterns in Canada

Background: COVID-public health measures may have impacted diabetes care through delayed care and reduced medication access. This study describes antihyperglycemic medication prescription patterns among adults with type 2 diabetes (T2D) before and during the COVID-pandemic in Canada. Methods: Using IQVIA’s longitudinal pharmacy based prescription data, antihyperglycemic prescriptions from March 1, 2018 to February 28, 2021 were analyzed among adults who had ≥1 prescription for a non-insulin antihyperglycemic drug. The number of people who: 1) had antihyperglycemic prescriptions,2) were newly started on antihyperglycemic drugs, and3) were newly diagnosed with T2D (inferred from prescriptions) were reported. Results: The number of people who had ≥1 antihyperglycemic prescription was comparable in the year of the COVID-pandemic (March 2020 to February 2021) and the year prior (March 20to February 2020) . The number of people who newly initiated a GLP-1RA, SGLT2i or second-generation basal insulin analogue decreased for the first few months of the pandemic (April to September 2020) with recovery thereafter. The number of people who were newly diagnosed with T2D decreased by 7% in the COVID-year. Conclusion: Fewer people initiated newer antihyperglycemic medications and fewer people were newly diagnosed with T2D in the first few months for the pandemic which may reflect reduced health care access. Disclosure A.Y.Cheng: Advisory Panel; Abbott, AstraZeneca, Bayer AG, Boehringer Ingelheim International GmbH, Dexcom, Inc., Eli Lilly and Company, HLS Theraoeutics, Insulet Corporation, Janssen Pharmaceuticals, Inc., Medtronic, Novo Nordisk, Sanofi, Board Member; Type 1 Diabetes Think Tank Network, Other Relationship; Diabetes Canada, Speaker's Bureau; Bausch Health, Canada, Merck & Co., Inc. R.Goldenberg: Consultant; IQVIA Inc., Speaker's Bureau; Amgen Canada, AstraZeneca, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Janssen Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk Canada Inc., Sanofi. I.E.Krawchenko: Speaker's Bureau; Janssen Pharmaceuticals, Inc. R.Tytus: Other Relationship; Banty , Boehringer Ingelheim International GmbH, Canadian Health Research Company, Merck & Co., Inc., Novo Nordisk, Pfizer Inc. J.Hahn: Employee; Novo Nordisk Canada Inc. A.R.Liu: Employee; Novo Nordisk A/S, Novo Nordisk Canada Inc. T.Lan: Other Relationship; Novo Nordisk Canada Inc. B.Millson: Other Relationship; Novo Nordisk Canada Inc. S.B.Harris: Consultant; Abbott, AstraZeneca, Eli Lilly and Company, Novo Nordisk, Sanofi, Other Relationship; Abbott, AstraZeneca, Bayer Inc., Dexcom, Eli Lilly and Company, HLS Therapeutics, Janssen Pharmaceuticals, Inc., Novo Nordisk, Sanofi, Research Support; Applied Therapeutics Inc., AstraZeneca, Canadian Institutes of Health Research, Juvenile Diabetes Research Foundation (JDRF) , Novo Nordisk, Sanofi, The Lawson Foundation.

Pharmacophore optimization of imidazole chalcones to modulate microtubule dynamics

We recently reported a new class of imidazole-based chalcones as potential antimitotic agents. In view of their promising cytotoxic activity, a comprehensive structure–activity relationship (SAR) of these compounds was undertaken focusing on four major structural variations: the length of the molecule, the Michael acceptor character, the nature and substitution pattern of ring B, and the nature of the amide functionality tethering ring B. These second-generation analogs (IBCs) demonstrated a superior bioactivity profile than the previously reported imidazole chalcones (referred to as IPEs). The analog IBC-2 with one less methylene group (nor series) and para-fluoro substituted ring B demonstrated the best cytotoxicity profile among the library of compounds. A computational analysis of the NCI-60 data associated both IBCs and the previously reported IPEs with the privileged pharmacological pharmacophore of chalcones. Interestingly, biological studies suggest that the imidazole ring is essential for cytotoxic activity of the elongated chalcone analogues. Immunofluorescence studies revealed that IBC-2, unlike IPEs, has the ability to induce microtubule catastrophe independently of Aurora-B inhibition. The effects of IBC-2 on microtubule dynamics are similar to those of Nocodazole, but the cell cycle effects appear to be different. In-silico studies demonstrate that the members of the new series have the ability to bind to the colchicine binding site of β-tubulin with binding scores similar to those of IPEs, corresponding chalcones and Nocodazole. Although tubulin binding can partially explain the biological effects of IBC-2, on-going target identification studies are aimed at further investigation of its biological targets.

Advancing Chelation Strategies for Large Metal Ions for Nuclear Medicine Applications

Nuclear medicine leverages radioisotopes of a wide range of elements, a significant portion of which are metals, for the diagnosis and treatment of disease. To optimally use radioisotopes of the metal ions, or radiometals, for these applications, a chelator that efficiently forms thermodynamically and kinetically stable complexes with them is required. The chelator also needs to attach to a biological targeting vector that locates pathological tissues. Numerous chelators suitable for small radiometals have been established to date, but chelators that work well for large radiometals are significantly less common. In this Account, we describe recent progress by us and others in the advancement of ligands for large radiometal chelation with emerging applications in nuclear medicine.First, we discuss and analyze the coordination chemistry of the chelator macropa, a macrocyclic ligand that contains the 18-crown-6 backbone and two picolinate pendent arms, with large metal ions in the context of nuclear medicine. This ligand is known for its unusual reverse size selectivity, the preference for binding large over small metal ions. The radiolabeling properties of macropa with large radiometals 225Ac3+, 132/135La3+, 131Ba2+, 223Ra2+, 213Bi3+, and related in vivo investigations are described. The development of macropa derivatives containing different pendent donors or rigidifying groups in the macrocyclic core is also briefly reviewed.Next, efforts to transform macropa into a radiopharmaceutical agent via covalent conjugation to biological targeting vectors are summarized. In this discussion, two types of bifunctional analogues of macropa reported in the literature, macropa-NCS and mcp-click, are presented. Their implementation in different radiopharmaceutical agents is discussed. Bioconjugates containing macropa attached to small-molecule targeting vectors or macromolecular antibodies are presented. The in vitro and in vivo evaluations of these constructs are also discussed.Lastly, chelators with dual size selectivity are described. This class of ligands exhibits good affinities for both large and small metal ions. This property is valuable for nuclear medicine applications that require the simultaneous chelation of both large and small radiometals with complementary therapeutic and diagnostic properties. Recently, we reported an 18-membered macrocyclic ligand called macrodipa that attains this selectivity pattern. This chelator, its second-generation analogue py-macrodipa, and their applications for chelating the medicinally relevant large 135La3+, 225Ac3+, 213Bi3+, and small 44Sc3+ ions are also presented. Studies with these radiometals show that py-macrodipa can effectively radiolabel and stably retain both large and small radiometals. Overall, this Account makes the case for innovative ligand design approaches for novel emerging radiometal ions with unusual coordination chemistry properties.

Differential Gene Expression Profiles between N-Terminal Domain and Ligand-Binding Domain Inhibitors of Androgen Receptor Reveal Ralaniten Induction of Metallothionein by a Mechanism Dependent on MTF1.

Simple SummaryInhibition of the androgen receptor (AR) remains the mainstay treatment for prostate cancer. All current therapies involving AR inhibition either directly or indirectly target its ligand-binding domain (LBD). We have developed the first novel compounds which target the N-terminal domain, (NTD) a region which is essential for AR transcriptional activity. First-generation ralaniten (NCT02606123), and second-generation EPI-7386 (NCT04421222) remain the only AR-NTD inhibitors to progress to clinical trials. Here we aim to characterize differences between different classes of AR antagonists targeting the AR-LBD and the AR-NTD, as well as next generation AR-NTD inhibitors. An incidental finding was that ralaniten was uniquely associated with increased metallothionein expression which was independent of AR activity. Instead, expression of metallothionein genes was driven by MTF-1 indicating a potential off-target effect. Neither AR-LBD inhibitor enzalutamide nor second-generation AR-NTD inhibitor EPI-7170 had this effect. This work has important implications for the development of novel AR-NTD inhibitors.Hormonal therapies for prostate cancer target the androgen receptor (AR) ligand-binding domain (LBD). Clinical development for inhibitors that bind to the N-terminal domain (NTD) of AR has yielded ralaniten and its analogues. Ralaniten acetate is well tolerated in patients at 3600 mgs/day. Clinical trials are ongoing with a second-generation analogue of ralaniten. Binding sites on different AR domains could result in differential effects on AR-regulated gene expression. Here, we provide the first comparison between AR-NTD inhibitors and AR-LBD inhibitors on androgen-regulated gene expression in prostate cancer cells using cDNA arrays, GSEA, and RT-PCR. LBD inhibitors and NTD inhibitors largely overlapped in the profile of androgen-induced genes that they each inhibited. However, androgen also represses gene expression by various mechanisms, many of which involve protein–protein interactions. De-repression of the transcriptome of androgen-repressed genes showed profound variance between these two classes of inhibitors. In addition, these studies revealed a unique and strong induction of expression of the metallothionein family of genes by ralaniten by a mechanism independent of AR and dependent on MTF1, thereby suggesting this may be an off-target. Due to the relatively high doses that may be encountered clinically with AR-NTD inhibitors, identification of off-targets may provide insight into potential adverse events, contraindications, or poor efficacy.

The ongoing evolution of basal insulin therapy over 100 years and its promise for the future.

The evolution of basal insulin therapy over the past 100 years since the discovery of insulin is a testimony to the biomedical bench-to-bedside process, wherein incremental advances in the basic sciences are progressively translated over time into a series of enhancements in clinical care, each building upon the success of its predecessors. The emergence of recombinant DNA technology and the resultant biosynthesis of human insulin in the 1980s provided the critical capacity to bioengineer designer insulin analogues with pharmacokinetic and pharmacodynamic properties that can better mimic, although not fully replicate, the effects of endogenous insulin secretion. Through these efforts, basal insulin therapy has progressed over this time from first-generation analogues (glargine U-100, detemir) to second-generation analogues (glargine U-300, degludec) to ultra-long-acting formulations that are suitable for administration once weekly (icodec). Each iteration in this progression has represented a step closer towards the goal of replicating the continuous secretion of insulin that normally comprises the basal output of the pancreatic beta-cells between meals, during episodes of fasting and overnight. However, it may be that we may have reached the achievable limit in the context of an "open-loop" approach, such that only with the addition of closed loop control will we be able to achieve physiologic basal insulin replacement. In this review, we will examine the evolution of basal insulin therapy over the past 100 years and its implications for patient care and outcomes in current practice and the future.

Enantioselective Synthesis and Profiling of Potent, Nonlinear Analogues of Antimalarial Tetraoxanes E209 and N205.

Synthetic endoperoxide antimalarials, such as 1,2,4-trioxolanes and 1,2,4,5-tetraoxanes, are promising successors for current front-line antimalarials, semisynthetic artemisinin derivatives. However, limited solubility of second-generation analogues in biological-relevant media represents a barrier in clinical development. We present methodology for the synthesis of nonlinear analogues of second-generation tetraoxane antimalarials E209 and N205 to investigate reduced molecular symmetry on in vitro antimalarial activity and physicochemical properties. While maintaining good antimalarial activity and metabolic stability, head-to-head comparison of linear and nonlinear counterparts showed up to 10-fold improvement in FaSSIF solubility for three of the four analogues studied. Pharmacokinetic studies in rats comparing a selected nonlinear analogue 14a and its parent N205 showed improvement on oral absorption and exposure in vivo with more than double the AUC and a significant increase in oral bioavailability (76% versus 41%). These findings provide support for further in vivo efficacy studies in preclinical animal species.

Genotoxicity and Epigenotoxicity of Carbazole-Derived Molecules on MCF-7 Breast Cancer Cells.

The carbazole compounds PK9320 (1-(9-ethyl-7-(furan-2-yl)-9H-carbazol-3-yl)-N-methylmethanamine) and PK9323 (1-(9-ethyl-7-(thiazol-4-yl)-9H-carbazol-3-yl)-N-methylmethanamine), second-generation analogues of PK083 (1-(9-ethyl-9H-carbazol-3-yl)-N-methylmethanamine), restore p53 signaling in Y220C p53-mutated cancer cells by binding to a mutation-induced surface crevice and acting as molecular chaperones. In the present paper, these three molecules have been tested for mutant p53-independent genotoxic and epigenomic effects on wild-type p53 MCF-7 breast adenocarcinoma cells, employing a combination of Western blot for phospho-γH2AX histone, Comet assay and methylation-sensitive arbitrarily primed PCR to analyze their intrinsic DNA damage-inducing and DNA methylation-changing abilities. We demonstrate that small modifications in the substitution patterns of carbazoles can have profound effects on their intrinsic genotoxic and epigenetic properties, with PK9320 and PK9323 being eligible candidates as “anticancer compounds” and “anticancer epi-compounds” and PK083 a “damage-corrective” compound on human breast adenocarcinoma cells. Such different properties may be exploited for their use as anticancer agents and chemical probes.

Evolution of a 4-Benzyloxy-benzylamino Chemotype to Provide Efficacious, Potent, and Isoform Selective PPARα Agonists as Leads for Retinal Disorders.

Peroxisome proliferator-activated receptor alpha (PPARα) is expressed in retinal Müller cells, endothelial cells, and in retinal pigment epithelium; agonism of PPARα with genetic or pharmacological tools ameliorates inflammation, vascular leakage, neurodegeneration, and neovascularization associated with retinal diseases in animal models. As such, PPARα is a promising drug target for diabetic retinopathy and age-related macular degeneration. Herein, we report proof-of-concept in vivo efficacy in an streptozotocin-induced vascular leakage model (rat) and preliminary pharmacokinetic assessment of a first-generation lead 4a (A91). Additionally, we present the design, synthesis, and evaluation of second-generation analogues, which led to the discovery of 4u and related compounds that reach cellular potencies <50 nM and exhibit >2,700-fold selectivity for PPARα over other PPAR isoforms. These studies identify a pipeline of candidates positioned for detailed PK/PD and pre-clinical evaluation.

1095-P: Early Hypoglycemia after Initiation of Second-Generation Basal Insulin (BI) Analogs: Patient Characteristics and Clinical Outcomes

Titration following initiation of BI tends to occur in the first 8-12 weeks. At this time, patients may be at risk of experiencing hypoglycemia, which itself may present a barrier to optimal glycemic control. BRIGHT was the first randomized controlled trial comparing efficacy and safety of two second-generation BI analogs in insulin-naïve patients with T2DM, and showed less hypoglycemia with insulin glargine 300 U/mL (Gla-300) vs. insulin degludec 100 U/mL (IDeg) in the initial 12-week titration period. We investigated patient characteristics and clinical outcomes (including HbA1c change, and hypoglycemia incidence during weeks 13-24) by the occurrence of early confirmed (≤70 mg/dL) hypoglycemia (in the titration period) using descriptive statistics. Participants experiencing hypoglycemia within the first 12 weeks tended to be older, had lower BMI, more impaired renal function, longer duration of diabetes, and were more likely to be using SUs at baseline (Table). Overall, hypoglycemia incidence during weeks 13-24 was lower in the group that did not experience hypoglycemia within the first 12 weeks. HbA1c reductions at week 12 were greater in those with hypoglycemia in the titration period. These findings suggest that patients experiencing early hypoglycemia with second-generation BI analogs have increased hypoglycemia risk in later stages of therapy. Disclosure S.B. Harris: Advisory Panel; Self; AstraZeneca, Janssen Pharmaceuticals, Inc., Lilly/Boehringer Ingelheim, Merck &amp; Co., Inc., Novo Nordisk A/S, Sanofi. Consultant; Self; AstraZeneca, Janssen Pharmaceuticals, Inc., Lilly/Boehringer Ingelheim, Merck &amp; Co., Inc., Novo Nordisk Inc., Sanofi. Research Support; Self; Abbott, AstraZeneca, Janssen Pharmaceuticals, Inc., Merck &amp; Co., Inc., Novo Nordisk A/S, Sanofi. Other Relationship; Self; Canadian Diabetes Association, Canadian Institutes of Health Research, The Lawson Foundation. L. Berard: Advisory Panel; Self; Eli Lilly and Company. Consultant; Self; Abbott, Ascensia Diabetes Care, AstraZeneca, Bayer AG, Becton, Dickinson and Company, Janssen Pharmaceuticals, Inc., LifeScan Canada, Mylan, Novo Nordisk Inc., Sanofi. Research Support; Self; Montmed Inc. Speaker's Bureau; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Merck &amp; Co., Inc. J. Westerbacka: Employee; Self; Sanofi. Stock/Shareholder; Self; Sanofi. Z. Bosnyak: Employee; Self; Sanofi. Stock/Shareholder; Self; Sanofi. L. Melas-Melt: Consultant; Self; Sanofi. F. Lauand: Employee; Self; Sanofi. T.S. Bailey: Advisory Panel; Self; Abbott. Consultant; Self; Capillary Biomedical, Inc., Eli Lilly and Company, Medtronic, Novo Nordisk Inc., Sanofi. Research Support; Self; Abbott, Ascensia Diabetes Care, Becton, Dickinson and Company, Boehringer Ingelheim Pharmaceuticals, Inc., Calibra Medical, Capillary Biomedical, Inc., Companion Medical, Dance Biopharm Holdings Inc., Dexcom, Inc., Diasome Pharmaceuticals, Inc., Eli Lilly and Company, GlySens Incorporated, Kowa Pharmaceutical Europe Co. Ltd., Lexicon Pharmaceuticals, Inc., Medtronic, Novo Nordisk Inc., POPS! Diabetes Care, POPS! Diabetes Care, Sanofi, Senseonics, vTv Therapeutics, Xeris Pharmaceuticals, Inc., Zealand Pharma A/S. Speaker's Bureau; Self; Abbott, MannKind Corporation, Medtronic, Novo Nordisk Inc., Sanofi US, Senseonics. K. Khunti: Advisory Panel; Self; Amgen Inc., AstraZeneca, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Novo Nordisk A/S, Sanofi. Consultant; Self; AstraZeneca, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Janssen Pharmaceuticals, Inc., Merck Sharp &amp; Dohme Corp., Novartis AG, Novo Nordisk A/S, Pfizer Inc., Sanofi-Aventis, Servier, Takeda Pharmaceutical Company Limited. Research Support; Self; AstraZeneca, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Novartis AG, Novo Nordisk A/S, Pfizer Inc., Sanofi-Aventis. Speaker's Bureau; Self; AstraZeneca, Berlin-Chemie AG, Boehringer Ingelheim International GmbH, Eli Lilly and Company, Janssen Pharmaceuticals, Inc., Menarini Group, Merck Sharp &amp; Dohme Corp., Novartis AG, Novo Nordisk A/S, Roche Pharma, Sanofi, Servier, Takeda Pharmaceutical Company Limited. Funding Sanofi (NCT02738151)

Small Molecules Target the Interaction between Tissue Transglutaminase and Fibronectin.

Tissue transglutaminase (TG2) is a multifunctional protein with enzymatic, GTP-ase, and scaffold properties. TG2 interacts with fibronectin (FN) through its N-terminus domain, stabilizing integrin complexes, which regulate cell adhesion to the matrix. Through this mechanism, TG2 participates in key steps involved in metastasis in ovarian and other cancers. High-throughput screening identified several small molecule inhibitors (SMI) for the TG2/FN complex. Rational medicinal chemistry optimization of the hit compound (TG53) led to second-generation analogues (MT1-6). ELISA demonstrated that these analogues blocked TG2/FN interaction, and bio-layer interferometry (BLI) showed that the SMIs bound to TG2. The compounds also potently inhibited cancer cell adhesion to FN and decreased outside-in signaling mediated through the focal adhesion kinase. Blockade of TG2/FN interaction by the small molecules caused membrane ruffling, delaying the formation of stable focal contacts and mature adhesions points and disrupted organization of the actin cytoskeleton. In an in vivo model measuring intraperitoneal dissemination, MT4 and MT6 inhibited the adhesion of ovarian cancer cells to the peritoneum. Pretreatment with MT4 also sensitized ovarian cancer cells to paclitaxel. The data support continued optimization of the new class of SMIs that block the TG2/FN complex at the interface between cancer cells and the tumor niche.

Spirocyclic and Bicyclic 8-Nitrobenzothiazinones for Tuberculosis with Improved Physicochemical and Pharmacokinetic Properties.

8-Nitrobenzothiazinones (BTZs) typified by the second-generation analogue PBTZ169 are a new class of antitubercular agents. The activity of BTZs and lipophilicity are tightly coupled since the molecular target DprE1 is located in the mycobacterial cell envelope. A series of analogues was designed to address the notorious insolubility of the BTZs while preserving the required lipophilicity. This was accomplished by decreasing the molecular planarity and symmetry through bioisosteric replacement of the piperazine moiety of PBTZ169 with spirocyclic and bicyclic diamines. Several promising compounds with improved aqueous solubilities were identified with potent antitubercular activity. Compound 5 was identified as the most promising candidate based on its excellent antitubercular activity (MIC of 32 nM), more than 1000-fold improvement in solubility, 2-fold lower clearance in mouse and human microsomes relative to PBTZ169, and promising pharmacokinetic parameters.

Recent advances in the genome mining of Aspergillus secondary metabolites (covering 2012-2018).

Secondary metabolites (SMs) produced by filamentous fungi possess diverse bioactivities that make them excellent drug candidates. Whole genome sequencing has revealed that fungi have the capacity to produce a far greater number of SMs than have been isolated, since many of the genes involved in SM biosynthesis are either silent or expressed at very low levels in standard laboratory conditions. There has been significant effort to activate SM biosynthetic genes and link them to their downstream products, as the SMs produced by these "cryptic" pathways offer a promising source for new drug discovery. Further, an understanding of the genes involved in SM biosynthesis facilitates product yield optimization of first-generation molecules and genetic engineering of second-generation analogs. This review covers advances made in genome mining SMs produced by Aspergillus nidulans, Aspergillus fumigatus, Aspergillus niger, and Aspergillus terreus in the past six years (2012-2018). Genetic identification and molecular characterization of SM biosynthetic gene clusters, along with proposed biosynthetic pathways, will be discussed in depth.

NMR Structure‐Based Optimization of Staphylococcus aureus Sortase A Pyridazinone Inhibitors

Staphylococcus aureus is a leading cause of hospital‐acquired infections in the USA and is a major health concern as methicillin‐resistant S. aureus and other antibiotic‐resistant strains are common. Compounds that inhibit the S. aureus sortase (SrtA) cysteine transpeptidase may function as potent anti‐infective agents as this enzyme attaches virulence factors to the bacterial cell wall. While a variety of SrtA inhibitors have been discovered, the vast majority of these small molecules have not been optimized using structure‐based approaches. Here we have used NMR spectroscopy to determine the molecular basis through which pyridazinone‐based small molecules inhibit SrtA. These inhibitors covalently modify the active cysteine thiol and partially mimic the natural substrate of SrtA by inducing the closure of an active site loop. Computational and synthetic chemistry methods led to second‐generation analogues that are ~70‐fold more potent than the lead molecule. These optimized molecules exhibit broad‐spectrum activity against other types of class A sortases, have reduced cytotoxicity, and impair SrtA‐mediated protein display on S. aureus cell surface. Our work shows that pyridazinone analogues are attractive candidates for further development into anti‐infective agents, and highlights the utility of employing NMR spectroscopy and solubility‐optimized small molecules in structure‐based drug discovery.Support or Funding InformationThis research was supported by funding from the National Institutes of Health (AI52217 to R.T.C. and M.E.J.; and GM31749 to J.A.M.). A.H.C. was supported by the UCLA Chemistry Biology Interface Training program (NIH T32GM008496). B.R.A was supported by the UCLA‐MBI Whitcome Pre‐Doctoral Training Grant. Additional support at UCSD has been provided by the National Science Foundation, the Howard Hughes Medical Institute, the Center for Theoretical Biological Physics, the National Biomedical Computation Resource, and the NSF Supercomputer Centers.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Manganese porphyrins as efficient catalysts in solvent-free cyclohexane oxidation

Novel non-symmetric third-generation manganese metalloporphyrins, chlorido(5-(4-nitrophenyl)-10,15,20-triphenyl-2,3,7,8,12,13,17,18 octobromoporphyrinate)manganese(III) (MnBr8P1) and the mixture of isomers chlorido(5,10-(4-nitrophenyl)-15,20-diphenyl-2,3,7,8,12,13,17,18-octabromoporphyrinate)manganese(III) and chlorido(5,15-(4-nitrophenyl)-10,20-diphenyl-2,3,7,8,12,13,17,18-octabromoporphyrinate)manganese(III) (cis/trans-MnBr8P2) were obtained from their second-generation analogues (MnP1 and cis/trans-MnP2). These four catalysts were used in cyclohexane oxidation reactions with iodosylbenzene (PhIO) or iodobenzene diacetate (PhI(OAc)2) in the presence or absence of solvent (CH2Cl2). Cyclohexanol (Cy-ol) and cyclohexanone (Cy-one) were the sole reaction products. Regardless of the system, third-generation catalysts MnBr8P1 and cis/trans-MnBr8P2 performed better than second-generation catalysts (MnP1 and cis/trans-MnP2, respectively). In solvent systems, cis/trans-MnBr8P2 afforded a greater total yield (%Cy-ol + %Cy-one) than systems using MnBr8P1, with an increase from 80 to 89% in PhIO and from 47 to 57% in PhI(OAc)2. The systems without solvent, showed to be viable and presented significant yields with PhIO as oxidant, with total yield of 30% for MnBr8P1, and 55% for cis/trans-MnBr8P2. Additionally, in systems with third-generation catalysts without solvent, selectivity was close to 100% for Cy-ol.

Abstract 113: Evaluating the anticancer activity of two flexible heteroarotinoid analogs on breast cancer

Abstract Flexible heteroarotiniods (flex-hets) are compounds derived from retinoic acid and recent studies have indicated that these compounds exhibit anti-cancer activity. Amongst the flexible heteroarotinoids, SHetA2 has been to shown block the growth of cervical, head and neck, kidney, lung, and ovarian cancers, and most recently, prostate and breast cancers. However, due to SHetA2’s limitations— a high degree of hydrophobicity, non-selectivity, and potential liver toxicity— a second generation of analogs was developed. Results from our recent study suggest that one of the second-generation analogs, 1-(1-(naphthalen-1-yl)ethyl)-3-(4-nitrophenyl)thiourea (SL-1-09) exhibits anti-cancer activities against both ERα+ and ER- breast cancer cells at micromolar concentrations. Since SL-1-09 is a racemic mixture, the R (SL-1-29) and S (SL-1-30) enantiomers were purified and investigated for their anti-cancer properties. Our results suggest that SL-1-30 has greater growth inhibitory effects on T47D, MCF7, MDA-MB-453, MDA-MB-468 cells in comparison to SL1-29, suggesting that the activity observed in SL-1-09 is likely associated with the S enantiomer. Consistent with this data, breast cancer cells treated with SL-1-09 and SL-1-30 express lower levels of proteins that regulate the cell cycle (i.e, cyclin A, cyclin B, cyclin D1, cyclin E and cdk2). These results demonstrate that SL-1-30 and SL-1-09 inhibit breast cancer cell growth, potentially by blocking cell cycle progression, however further studies are necessary for determining the mechanisms of action. Citation Format: Emily Ginn, Hongye Zou, Maryam M. Fallatah, Shengquan Liu, Maggie C. Louie. Evaluating the anticancer activity of two flexible heteroarotinoid analogs on breast cancer [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 113. doi:10.1158/1538-7445.AM2017-113