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Publication Enantioselective Total Syntheses of (+)-Kasugamycin and (+)-Kasuganobiosamine Highlighting a Sulfamate-Tethered Aza-Wacker Cyclization Strategy(American Chemical Society, 2024-07-06) Mandal, Gour Hari; Kelley, Steven P.; Sathyamoorthi, ShyamHere, we present the first enantioselective total syntheses of the natural products (+)-kasugamycin, a potent antifungal antibiotic, and (+)-kasuganobiosamine, a compound that results from the degradation of kasugamycin. Salient features of these syntheses include a second-generation enantioselective preparation of a kasugamine derivative (efficiency much improved relative to that of our first chiral-pool effort) and our laboratory's sulfamate-tethered -Wacker cyclization.Publication Increased Risk of Breakthrough SARS-CoV-2 Infections in Patients with Colorectal Cancer: A Population-Based Propensity-Matched Analysis(MDPI, 2024-04-24) Alsakarneh, Saqr; Jaber, Fouad; Qasim, Hana; Massad, Abdallah; Alzghoul, Hamza; Abboud, Yazan; Dahiya, Dushyant Singh; Bilal, Mohammad; Shaukat, AasmaBackground/Objectives: This study aimed to investigate the association between colorectal cancer (CRC) and the risk of breakthrough respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in vaccinated patients with CRC. Methods: This retrospective cohort study used the TriNetX research network to identify vaccinated patients with CRC. Patients were matched using propensity score matching (PSM) and divided into patients with CRC and control (without history of CRC) groups. The primary outcome was the risk of breakthrough SARS-CoV-2 in vaccinated patients. The secondary outcome was a composite of all-cause emergency department (ED) visits, hospitalization, and death during the follow-up period after the diagnosis of COVID-19. Results: A total of 15,416 vaccinated patients with CRC were identified and propensity matched with 15,416 vaccinated patients without CRC. Patients with CRC had a significantly increased risk for breakthrough infections compared to patients without CRC (aOR = 1.78; [95% CI: 1.47–2.15]). Patients with CRC were at increased risk of breakthrough SARS-CoV-2 infections after two doses (aOR = 1.71; [95% CI: 1.42–2.06]) and three doses (aOR = 1.36; [95% CI: 1.09–1.69]) of SARS-CoV-2 vaccine. Vaccinated patients with CRC were at a lower risk of COVID-19 infection than unvaccinated CRC patients (aOR = 0.342; [95% CI: 0.289–0.404]). The overall composite outcome (all-cause ED visits, all-cause hospitalization, and all-cause death) was 51.6% for breakthrough infections, which was greater than 44.3% for propensity score-matched patients without CRC (aOR = 1.79; [95% CI: 1.29–2.47]). Conclusions: This cohort study showed significantly increased risks for breakthrough SARS-CoV-2 infection in vaccinated patients with CRC. Breakthrough SARS-CoV-2 infections in patients with CRC were associated with significant and substantial risks for hospitalizations.Publication Ring Opening of Aziridines by Pendant Silanols Allows for Stereospecific Preparations of 1′-Amino-tetrahydrofurans(American Chemical Society, 2023-05-30) Nirpal, Appasaheb K.; Nagamalla, Someshwar; Mague, Joel T.; Sathyamoorthi, ShyamWe have developed a highly stereospecific cyclization of aziridine silanols into 1′-amino-tetrahydrofurans. Our protocol of stirring a substrate with 10 mol % Sc (OTf)3 and 1 equivalent of NaHCO3 in CH2Cl2 is mild and compatible with a range of activating aziridine N-substituents (including tosylates, mesylates, and carbamates) and functional groups on the alkyl chains (including substituted aryl rings, alkyl bromides, and alkyl ethers). In all cases examined, trans di-substituted aziridine silanols give products with an erythro configuration; conversely, cis di-substituted aziridine silanols give products with a threo configuration. While literature syntheses of 1′-amino-tetrahydrofurans exist, only one example, contemporaneous with our work, uses a similar cyclization for their construction. Control experiments demonstrate that, for this transformation, the silanol is not particularly privileged, and a variety of protecting groups on the alcohol (including other silicon protecting groups, benzyl ethers, and MOM ethers) are compatible with product formation.Publication The Kappa Opioid Receptor Agonist 16-Bromo Salvinorin A Has Anti-Cocaine Effects without Significant Effects on Locomotion, Food Reward, Learning and Memory, or Anxiety and Depressive-like Behaviors(MDPI, 2023-06-19) van de Wetering, Ross; Ewald, Amy; Welsh, Susan; Kornberger, Lindsay; Williamson, Samuel E.; McElroy, Bryan D.; Butelman, Eduardo R.; Prisinzano, Thomas E.; Kivell, Bronwyn M.Kappa opioid receptor (KOR) agonists have preclinical antipsychostimulant effects; however, adverse side effects have limited their therapeutic development. In this preclinical study, conducted in Sprague Dawley rats, B6-SJL mice, and non-human primates (NHPs), we evaluated the G-protein-biased analogue of salvinorin A (SalA), 16-bromo salvinorin A (16-BrSalA), for its anticocaine effects, side effects, and activation of cellular signaling pathways. 16-BrSalA dose-dependently decreased the cocaine-primed reinstatement of drug-seeking behavior in a KOR-dependent manner. It also decreased cocaine-induced hyperactivity, but had no effect on responding for cocaine on a progressive ratio schedule. Compared to SalA, 16-BrSalA had an improved side effect profile, with no significant effects in the elevated plus maze, light–dark test, forced swim test, sucrose self-administration, or novel object recognition; however, it did exhibit conditioned aversive effects. 16-BrSalA increased dopamine transporter (DAT) activity in HEK-293 cells coexpressing DAT and KOR, as well as in rat nucleus accumbens and dorsal striatal tissue. 16-BrSalA also increased the early phase activation of extracellular-signal-regulated kinases 1 and 2, as well as p38 in a KOR-dependent manner. In NHPs, 16-BrSalA caused dose-dependent increases in the neuroendocrine biomarker prolactin, similar to other KOR agonists, at doses without robust sedative effects. These findings highlight that G-protein-biased structural analogues of SalA can have improved pharmacokinetic profiles and fewer side effects while maintaining their anticocaine effects.Publication Covalent Tethers for Precise Amino Alcohol Syntheses: Ring Opening of Epoxides by Pendant Sulfamates and Sulfamides(American Chemical Society, 2023-02-06) Nagamalla, Someshwar; Mague, Joel T.; Sathyamoorthi, ShyamWe describe the development of the first ring opening of epoxides using pendant sulfamates and sulfamides. These reactions are promoted by a base and proceed under mild conditions to afford oxathiazinanes and cyclic sulfamides with excellent diastereoselectivity and regiocontrol. The reactions scale well, and the products serve as synthons for ring-opening reactions.Publication Sulfamate-Tethered Aza-Wacker Cyclization Strategy for the Syntheses of 2-Amino-2-deoxyhexoses: Preparation of Orthogonally Protected d-Galactosamines(American Chemical Society, 2023-01-17) Paul, Debobrata; Mague, Joel T.; Sathyamoorthi, ShyamWe present a new strategy for the assembly of protected d-galactosamine synthons. Our route uses a sulfamate-tethered aza-Wacker cyclization as a key step and commences from d-erythrono-1,4-lactone. This stands in contrast to most literature syntheses of 2-amino-2-deoxyhexose derivatives, as these generally employ glycals or hexoses as starting materials. This strategy may serve as a template for the assembly of many other 2-amino-2-deoxyhexoses with protection patterns difficult to access by conventional methods.Publication Ring Opening of Aziridines by Pendant Silanols Allows for Preparations of (±)-Clavaminol H, (±)-Des-Acetyl-Clavaminol H, (±)-Dihydrosphingosine, and (±)-N-Hexanoyldihydrosphingosine(American Chemical Society, 2022-08-11) Nagamalla, Someshwar; Paul, Debobrata; Mague, Joel T.; Sathyamoorthi, ShyamWe present a unique strategy for the synthesis of vicinal amino alcohols. Ring opening of aziridines with pendant silanols is compatible with a range of substrates. To engage productively in ring opening, the aziridine must be at least mildly activated, and a variety of such N-substituents are tolerated. The utility of this methodology is highlighted in facile preparations of the natural products (±)-Clavaminol H, (±)-dihydrosphingosine, and (±)-N-hexanoyldihydrosphingosine as well as a natural product analogue (±)-des-acetyl-Clavaminol H.Publication Highly Stereospecific Cyclizations of Homoallylic Silanols(American Chemical Society, 2022-07-28) Shinde, Anand H.; Dhokale, Ranjeet A.; Mague, Joel T.; Sathyamoorthi, ShyamWe demonstrate that di-tert-butylsilanols are competent nucleophiles for the intramolecular interception of palladium π-allyl species. In these reactions, allyl ethyl carbonates are the best precursors for the formation of palladium π-allyl intermediates, and [(Cinnamyl)PdCl]2/BINAP is superior to other Pd salt/ligand framework combinations. Our optimized protocol is compatible with a variety of silanol substrates. Importantly, the cyclization is perfectly stereospecific, proceeding via an anti-syn mechanism, which stands in contrast to reported analogous reactions of alcohols and phenols, known to proceed via an anti-anti mechanism. The alkenes in the product dioxasilinanes serve as blank slates for further functionalization.Publication N-arylated oxathiazinane heterocycles are convenient synthons for 1,3-amino ethers and 1,3-amino thioethers(Springer, 2020-05-17) Shinde, Anand H.; Nagamalla, Someshwar; Sathyamoorthi, ShyamThis communication describes a variety of nucleophilic ring openings of N-arylated oxathiazinane heterocycles. We find that this reaction is compatible with phenoxides, naphthoxides, and thiolates and allows for the rapid assembly of N-aryl-amino ethers and N-aryl-amino thioethers. Fourteen examples are shown and a mechanistic pathway is hypothesized.Publication Synthesis of Cycloheptatriene-Containing Azetidine Lactones(American Chemical Society, 2022-05-23) Singh, Manvendra; Gaskins, Bryce; Johnson, Daniel R.; Elles, Christopher G.; Boskovic, ZarkoWe prepared a collection of complex cycloheptatriene-containing azetidine lactones by applying two key photochemical reactions: “aza-Yang” cyclization and Buchner carbene insertion into aromatic rings. While photolysis of phenacyl amines leads to a rapid charge transfer and elimination, we found that a simple protonation of the amine enables the formation of azetidinols as single diastereomers. We provide evidence, through ultrafast spectroscopy, for the electron transfer from free amines in the excited state. Further, we characterize the aza-Yang reaction by establishing the dependence of the initial reaction rates on the rates of photon absorption. An unanticipated change in reactivity in morpholine analogues is explained through interactions with the tosylate anion. The Buchner reaction proceeds with a slight preference for one diastereomer over the other, and successful reaction requires electron-donating carbene-stabilizing substituents. Overall, 16 compounds were prepared over seven steps. Guided by an increase in structural complexity, efforts such as this one extend the reach of chemists into unexplored chemical space and provide useful quantities of new compounds for studies focused on their properties.Publication Highly Regio- and Diastereoselective Tethered Aza-Wacker Cyclizations of Alkenyl Phosphoramidates(American Chemical Society, 2021-10-19) Shinde, Anand H.; Thomas, Annu Anna; Mague, Joel T.; Sathyamoorthi, ShyamWe present highly diastereoselective tethered aza-Wacker cyclization reactions of alkenyl phosphoramidates. “Arming” the phosphoramidate tether with 5-chloro-8-quinolinol was essential to achieving >20:1 diastereoselectivity in these reactions. The substrate scope with respect to alkenyl alcohols and phosphoramidate tether was extensively explored. The scalability of the oxidative cyclization was demonstrated, and the product cyclophosphoramidates were shown to be valuable synthons, including for tether removal. With chiral alkenyl precursors, enantiopure cyclic phosphoramidates were formed.Publication Oxidative Cyclization of Sulfamates onto Pendant Alkenes(American Chemical Society, 2020-01-13) Shinde, Anand H.; Sathyamoorthi, ShyamThis communication discloses the first examples of aza-Wacker cyclizations of sulfamate esters. Within the realm of related cyclization reactions, this protocol is differential in that it forms six-membered rings in good yield and uses catalytic amounts of palladium(0) rather than palladium(II) salts. These reactions scale well, and their products are demonstrated to be valuable synthetic intermediates.Publication Human cytochrome P450 17A1 structures with metabolites of prostate cancer drug abiraterone reveal substrate-binding plasticity and a second binding site(Elsevier, 2023-03-09) Petrunak, Elyse M.; Bart, Aaron G.; Peng, Hwei-Ming; Auchus, Richard J.; Scott, Emily E.Abiraterone acetate is a first-line therapy for castration-resistant prostate cancer. This prodrug is deacetylated in vivo to abiraterone, which is a potent and specific inhibitor of cytochrome P450 17A1 (CYP17A1). CYP17A1 performs two sequential steps that are required for the biosynthesis of androgens that drive prostate cancer proliferation, analogous to estrogens in breast cancer. Abiraterone can be further metabolized in vivo on the steroid A ring to multiple metabolites that also inhibit CYP17A1. Despite its design as an active-site–directed substrate analog, abiraterone and its metabolites demonstrate mixed competitive/noncompetitive inhibition. To understand their binding, we solved the X-ray structures of CYP17A1 with three primary abiraterone metabolites. Despite different conformations of the steroid A ring and substituents, all three bound in the CYP17A1 active site with the steroid core packed against the I helix and the A ring C3 keto or hydroxyl oxygen forming a hydrogen bond with N202 similar to abiraterone itself. The structure of CYP17A1 with 3-keto, 5α-abiraterone was solved to 2.0 Å, the highest resolution to date for a CYP17A1 complex. This structure had additional electron density near the F/G loop, which is likely a second molecule of the inhibitor and which may explain the noncompetitive inhibition. Mutation of the adjacent Asn52 to Tyr positions its side chain in this space, maintains enzyme activity, and prevents binding of the peripheral ligand. Collectively, our findings provide further insight into abiraterone metabolite binding and CYP17A1 function.Publication Formulation Studies to Develop Low-cost, Orally-delivered Secretory IgA Monoclonal Antibodies for Passive Immunization Against Enterotoxigenic Escherichia coli (Dataset)(Elsevier, 2023) Bajoria, Sakshi; Antunez, Lorena R.; Kumru, Ozan S.; Klempner, Mark; Wang, Yang; Cavacini, Lisa A.; Joshi, Sangeeta B.; Volkin, David B.Enterotoxigenic Escherichia coli (ETEC) is a common cause for diarrheal infections in children in low- and middle-income countries (LMICs). To date, no ETEC vaccine candidates have been approved. Passive immunization with low-cost, oral formulations of secretory IgA (sIgA) against ETEC is an alternative approach to protect high-risk populations in LMICs. Using a model sIgA monoclonal antibody (anti-LT sIgA2-mAb), the stability profiles of different formulations were assessed during storage and in in vitro digestion models (mimicking in vivo oral delivery). First, by employing various physicochemical techniques and an LT-antigen binding assay, three formulations with varying acid-neutralizing capacity (ANC) were evaluated to stabilize sIgA2-mAb during stress studies (freeze-thaw, agitation, elevated temperature) and during exposure to gastric phase digestion. Next, a low-volume, in vitro intestinal digestion model was developed to screen various additives to stabilize sIgA2-mAb in the intestinal phase. Finally, combination of high ANC buffers and decoy proteins were assessed to collectively protect sIgA2-mAb during in vitro sequential (stomach to intestine) digestion. Based on the results, we demonstrate the feasibility of low-cost, ‘single-vial’, liquid formulations of sIgA-mAbs delivered orally after infant feeding for passive immunization, and we suggest future work based on a combination of in vitro and in vivo stability considerations.Publication Cellular Target Deconvolution of Small Molecules Using a Selection-Based Genetic Screening Platform(American Chemical Society, 2022-09-22) Zhao, Junxing; Tang, Zhichao; Selvaraju, Manikandan; Johnson, Kristen A.; Douglas, Justin T.; Gao, Philip F.; Petrassi, H. Michael; Wang, Michael Zhuo; Wang, JingxinSmall-molecule drug target identification is an essential and often rate-limiting step in phenotypic drug discovery and remains a major challenge. Here, we report a novel platform for target identification of activators of signaling pathways by leveraging the power of a clustered regularly interspaced short palindromic repeats (CRISPR) knockout library. This platform links the expression of a suicide gene to the small-molecule-activated signaling pathway to create a selection system. With this system, loss-of-function screening using a CRISPR single-guide (sg) RNA library positively enriches cells in which the target has been knocked out. The identities of the drug targets and other essential genes required for the activity of small molecules of interest are then uncovered by sequencing. We tested this platform on BDW568, a newly discovered type-I interferon signaling activator, and identified stimulator of interferon genes (STING) as its target and carboxylesterase 1 (CES1) to be a key metabolizing enzyme required to activate BDW568 for target engagement. The platform we present here can be a general method applicable for target identification for a wide range of small molecules that activate different signaling pathways.Publication Combination Treatment of Withalongolide a Triacetate with Cisplatin Induces Apoptosis by Targeting Translational Initiation, Migration, and Epithelial to Mesenchymal Transition in Head and Neck Squamous Cell Carcinoma(MDPI, 2022-12-19) Subramanian, Chitra; Spielbauer, Katie K.; Pearce, Robin; Kovatch, Kevin J.; Prince, Mark E.; Timmermann, Barbara N.; Cohen, Mark S.Treatment regimens for head and neck squamous cell carcinoma (HNSCC) typically include cisplatin and radiotherapy and are limited by toxicities. We have identified naturally derived withalongolide A triacetate (WGA-TA) from Physalis longifolia as a lead compound for targeting HNSCC. We hypothesized that combining WGA-TA with cisplatin may allow for lower, less toxic cisplatin doses. HNSCC cell lines were treated with WGA-TA and cisplatin. After treatment with the drugs, the cell viability was determined by MTS assay. The combination index was calculated using CompuSyn. The expression of proteins involved in the targeting of translational initiation complex, epithelial to mesenchymal transition (EMT), and apoptosis were measured by western blot. Invasion and migration were measured using the Boyden-chamber assay. Treatment of MDA-1986 and UMSCC-22B cell lines with either WGA-TA or cisplatin alone for 72 h resulted in a dose dependent decrease in cell viability. Cisplatin in combination with WGA-TA resulted in significant synergistic cell death starting from 1.25 μM cisplatin. Combination treatment with WGA-TA resulted in lower cisplatin dosing while maintaining the downregulation of translational initiation complex proteins, the induction of apoptosis, and the blockade of migration, invasion, and EMT transition. These results suggest that combining a low concentration of cisplatin with WGA-TA may provide a safer, more effective therapeutic option for HNSCC that warrants translational validation.Publication In-Depth Characterization of Endo-Lysosomal Aβ in Intact Neurons(MDPI, 2022-08-20) McKendell, Alec K.; Houser, Mei C. Q.; Mitchell, Shane P. C.; Wolfe, Michael S.; Berezovska, Oksana; Maesako, MasatoAmyloid-beta (Aβ) peptides are produced within neurons. Some peptides are released into the brain parenchyma, while others are retained inside the neurons. However, the detection of intracellular Aβ remains a challenge since antibodies against Aβ capture Aβ and its precursor proteins (i.e., APP and C99). To overcome this drawback, we recently developed 1) the C99 720-670 biosensor for recording γ-secretase activity and 2) a unique multiplexed immunostaining platform that enables the selective detection of intracellular Aβ with subcellular resolution. Using these new assays, we showed that C99 is predominantly processed by γ-secretase in late endosomes and lysosomes, and intracellular Aβ is enriched in the same subcellular loci in intact neurons. However, the detailed properties of Aβ in the acidic compartments remain unclear. Here, we report using fluorescent lifetime imaging microscopy (FLIM) that intracellular Aβ includes both long Aβ intermediates bound to γ-secretase and short peptides dissociated from the protease complex. Surprisingly, our results also suggest that the dissociated Aβ is bound to the glycoproteins on the inner membrane of lysosomes. Furthermore, we show striking cell-to-cell heterogeneity in intracellular Aβ levels in primary neurons and APP transgenic mouse brains. These findings provide a basis for the further investigation of the role(s) of intracellular Aβ and its relevance to Alzheimer’s disease (AD).Publication Novel C-terminal heat shock protein 90 inhibitors target breast cancer stem cells and block migration, self-renewal, and epithelial–mesenchymal transition(Wiley Open Access, 2020-04-07) Subramanian, Chitra; Grogan, Patrick T.; Wang, Ton; Bazzill, Joseph; Zuo, Ang; White, Peter T.; Kalidindi, Avinaash; Kuszynski, Dawn; Wang, Grace; Blagg, Brian S. J.; Cohen, Mark S.In patients with triple-negative breast cancer (TNBC), evidence suggests that tumor-initiating cells (TIC) have stem cell-like properties, leading to invasion and metastasis. HSP90 plays a critical role in the conformational maintenance of many client proteins in TIC development. Therefore, we hypothesize that the novel C-terminal HSP90 inhibitors KU711 and KU758 can target TIC and represent a promising strategy for overcoming metastasis. Human breast cancer cells (MDA-MB-468LN, MDA-MB-231) treated with the HSP90 inhibitors KU711, KU758, and 17-AAG showed a 50–80% decrease in TIC markers CD44 and aldehyde dehydrogenase (P < 0.01) as assessed by flow cytometry. A decrease in sphere formation, which was used to assess self-renewal, was observed after the treatment of TNBC cells starting at 2.5 µm KU711 and 0.31 µm KU758. KU compounds also blocked the invasion and migration of TNBC cells in a dose-dependent manner. The knockdown of HSP90 clients was observed without any change in prosurvival HSP70 levels. In vivo, in a murine orthotopic breast cancer model, treatment with KU758 and KU711 yielded an approximately twofold and a fourfold reduction in tumor volumes versus control, respectively, without demonstrated toxicity. In conclusion, C-terminal HSP90 inhibitors are potent novel therapeutics against TNBC in vitro and in vivo as they target TICs and block invasion, EMT transition, and self-renewal.Publication Flavin Metallaphotoredox Catalysis: Synergistic Synthesis in Water(American Chemical Society, 2022-03-22) Chilamari, Maheshwerreddy; Immel, Jacob R.; Chen, Pei-Hsuan; Alghafli, Bayan M.; Bloom, StevenCombining a transition metal with a photocatalyst can drive modern synthetic chemistry. For transformations performed in water, this concept has been largely unexplored. We report the successful merger of a biocompatible flavin photocatalyst with a palladium catalyst to build isotopically enriched peptidomimetics, to mediate conjugate addition and C–H functionalization reactions, and to assemble unprotected proteinogenic and nonproteinogenic peptides, in water. We detail the important role of the ligand and the palladium oxidation state for controlling product selectivity when constructing synthetic peptides.Publication Ring Opening of Epoxides by Pendant Silanols(American Chemical Society, 2022-01-18) Nagamalla, Someshwar; Mague, Joel T.; Sathyamoorthi, ShyamWe present a new ring-opening reaction of epoxides by pendant silanols, catalyzed by either Ph3C+BF4– or BINOL-phosphoric acid. Silanol epoxides derived from trans-allylic alcohols, cis-allylic alcohols, trans-homoallylic alcohols, and cis-homoallylic alcohols were all compatible and gave products from either endo- or exo-ring opening. With silanol epoxides derived from 4-alkenyl silanols, an unusual rearrangement to tetrahydrofuran products was observed. The utility of this methodology was demonstrated in a short preparation of protected d-arabitol.