Cancer is the second leading cause of death worldwide. >90 % of cancer-related deaths are due to metastasis, a process that depends on the ability of cancer cells to leave the primary tumor, migrate, and colonize different tissues. Inositol 1,4,5-trisphosphate receptor (IPR)-mediated Ca signaling plays an essential role in maintaining the homeostasis of cancer cells and the sustained proliferation.
View Article and Find Full Text PDFHerein, the execution of synthetic strategies solving scalability issues observed in the original route is reported, increasing the total yield by 50% compared to the previously disclosed synthesis. A notable restructuring of the route's initial steps to reach a common allylic alcohol intermediate employs a highly stereoselective epoxidation method and avoids superfluous protecting group manipulations while limiting dependence on kinetic resolution in establishing stereochemistry for four of the six chiral centers in (+)-desmethylxestospongin B. Different protecting group strategies to avoid problems with their subsequent removal were considered and enacted; to this end, material was retained as byproducts were suppressed.
View Article and Find Full Text PDFEndothelial cells express multiple receptors mediating estrogen responses; including the G protein-coupled estrogen receptor (GPER). Past studies on nitric oxide (NO) production elicited by estrogens raised the question whether 17-β-estradiol (E2) and natural phytoestrogens activate equivalent mechanisms. We hypothesized that E2 and phytoestrogens elicit NO production via coupling to distinct intracellular pathways signalling.
View Article and Find Full Text PDFLiver fibrosis, characterized by excessive extracellular matrix (ECM) deposition, can progress to cirrhosis and increases the risk of liver cancer. Hepatic stellate cells (HSCs) play a pivotal role in fibrosis progression, transitioning from a quiescent to activated state upon liver injury, wherein they proliferate, migrate, and produce ECM. Calcium signaling, involving the inositol 1,4,5-trisphosphate receptor (IP3R), regulates HSC activation.
View Article and Find Full Text PDFChimeric antigen receptor T-cell (CAR T-cell) therapy has revolutionized the treatment of relapsed/refractory (R/R) large B-cell lymphoma (LBCL). We describe the real-world baseline characteristics, efficacy, safety, and post-relapse outcomes of adult patients with R/R LBCL who received CAR T-cell therapy at the University of California San Diego. A total of 66 patients with LBCL were treated with tisagenlecleucel or axicabtagene ciloleucel.
View Article and Find Full Text PDFStereoselective synthesis of α-fluoro carboxylic acids by the Ireland-Claisen rearrangement can provide a straightforward approach to this class of compounds. We report a systematic investigation of base-dependent stereocontrol in the Ireland-Claisen rearrangement of α-fluoro esters. For substrates with various substitution patterns, the use of KN(SiMe) in toluene afforded rearrangement products corresponding to the ()-enolate intermediate with a practically useful diastereoselectivity and yield.
View Article and Find Full Text PDFRemote stereocontrol in the Ireland-Claisen rearrangement using a chiral acetonide that serves as internal stereocontrol element is an effective and general method for chirality transfer from a δ-hydroxyl group in the allylic alcohol unit. This strategy circumvents the need for redundant chirality at the α-position allylic alcohol, while simultaneously producing a terminal alkene that can streamline synthetic applications and complex molecule synthesis planning.
View Article and Find Full Text PDFCase: Two cases of revision total hip arthroplasty (THA) for pseudotumor and infection with persistent postoperative bleeding because of angiosarcoma are presented. After surgery, both patients' health deteriorated because of hypovolemic shock despite transfusion, pressors, embolization, and prothrombotics. Diagnosis was obscure and delayed despite extensive imaging.
View Article and Find Full Text PDFWe report a method for direct enantioselective alkylation of 3-alkynoic and 2,3-alkendioic acids that form quaternary stereogenic centers, and application of this method to the total enantioselective synthesis of a complex alkaloid (+)-goniomitine. The methods were effective in the alkylation of both 3-alkynoic acids, 2,3-alkendioic acids substrates with a broad range of heterocyclic and functionalized alkyl group substituents. Accompanying crystallographic studies provide mechanistic insight into the structure of well-defined chiral aggregates, highlighting cation-π interactions between lithium and alkyne groups.
View Article and Find Full Text PDFIntroduction: Persons with haemophilia (PWH) have a higher prevalence of hypertension compared to the general population, which cannot be explained entirely by the usual cardiovascular risk factors. Neutralizing antibodies (inhibitors) against clotting factors might have some relation to cardiovascular disease in PWH. However, whether inhibitors facilitate hypertension is unknown.
View Article and Find Full Text PDFCalcium is an important second messenger regulating a bioenergetic response to the workloads triggered by neuronal activation. In embryonic mouse cortical neurons using glucose as only fuel, activation by NMDA elicits a strong workload (ATP demand)-dependent on Na and Ca entry, and stimulates glucose uptake, glycolysis, pyruvate and lactate production, and oxidative phosphorylation (OXPHOS) in a Ca-dependent way. We find that Ca upregulation of glycolysis, pyruvate levels, and respiration, but not glucose uptake, all depend on Aralar/AGC1/Slc25a12, the mitochondrial aspartate-glutamate carrier, component of the malate-aspartate shuttle (MAS).
View Article and Find Full Text PDFThe scalable synthesis of the oxaquinolizidine marine natural product desmethylxestospongin B is based on the early application of Ireland-Claisen rearrangement, macrolactamization, and a late-stage installation of the oxaquinolizidine units by lactam reduction. The synthesis serves as the source of material to investigate calcium signaling and its effect on mitochondrial metabolism in various cell types, including cancer cells.
View Article and Find Full Text PDFCyclic imine toxins exhibit fast acting neurotoxicity and lethality by respiratory arrest in mice explained by their potent antagonistic activity against muscular nicotinic acetylcholine receptors. We performed a survey of gymnodimine-A, 13-desmethyl spirolide-C, 13,19-didesmethyl spirolide-C, 20-methyl spirolide-G, pinnatoxin-A, pinnatoxin-G, portimine-A and 28-O-palmitoyl ester of pinnatoxin-G in 36 shellfish samples collected in coastal areas of 8 European countries using a microplate receptor binding assay and UPLC-MS/MS for toxin identification and quantification. The major toxins found in these samples were pinnatoxin-G, 20-methyl spirolide-G, 13-desmethyl spirolide-C, gymnodimine-A and portimine-A.
View Article and Find Full Text PDFA method has been developed for the α-tertiary alkylation of zirconium enolates of -(arylacetyl)oxazolidinones. This reaction directly installs an all-carbon quaternary center to a benzylic tertiary carbon in a highly diastereoselective manner.
View Article and Find Full Text PDFAn asymmetric total synthesis of [ C ]-anatoxin-a ([ C ]-1) has been developed from commercially available ethyl [ C ]-acetoacetate ([ C ]-15). The unique requirements associated with isotope incorporation inspired a new, robust, and highly scalable route, providing access to 0.110 g of this internal standard for use in the detection and precise quantification of anatoxin-a in freshwater.
View Article and Find Full Text PDFDespite a growing acceptance that withdrawal symptoms can emerge following discontinuation of cannabis products, especially in high-intake chronic users, there are no Food and Drug Administration (FDA)-approved treatment options. Drug development has been hampered by difficulties studying cannabis withdrawal in laboratory animals. One preclinical approach that has been effective in studying withdrawal from drugs in several pharmacological classes is antagonist drug discrimination.
View Article and Find Full Text PDFDirect enantioselective α-alkylation of 2-alkylpyridines provides access to chiral pyridines via an operationally simple protocol that obviates the need for prefunctionalization or preactivation of the substrate. The alkylation is accomplished using chiral lithium amides as noncovalent stereodirecting auxiliaries. Crystallographic and solution NMR studies provide insight into the structure of well-defined chiral aggregates in which a lithium amide reagent directs asymmetric alkylation.
View Article and Find Full Text PDFPinnatoxins (PnTXs) A-H constitute an emerging family belonging to the cyclic imine group of phycotoxins. Interest has been focused on these fast-acting and highly-potent toxins because they are widely found in contaminated shellfish. Despite their highly complex molecular structure, PnTXs have been chemically synthetized and demonstrated to act on various nicotinic acetylcholine receptor (nAChR) subtypes.
View Article and Find Full Text PDFEfficient asymmetric alkylation of β,γ-unsaturated carboxylic acids without prior functionalization is enabled by chiral lithium amides. Enantioselectivity is imparted by a putative mixed lithium amide-enediolate aggregate that acts a traceless auxiliary formed in situ, allowing for a direct asymmetric alkylation and a simple recovery of the chiral reagent.
View Article and Find Full Text PDF: Mitochondrial optic neuropathies such as Leber's Hereditary Optic Neuropathy (LHON) and Dominant Optic Atrophy (DOA) have been shown to produce an optic neuropathy secondary to retinal ganglion cell loss with thinning of the retinal ganglion cell complex (RGCC). : We performed a retrospective analysis assessing the thicknesses of the peripapillary retinal nerve fiber layer (pRNFL) along with the macular retinal ganglion cell-inner plexiform layer (RGC-IPL) using optical coherence tomography (OCT). We compared these changes among acute and chronic LHON, DOA, and normal healthy control patients.
View Article and Find Full Text PDFNatural products and their derivatives continue to be wellsprings of nascent therapeutic potential. However, many laboratories have limited resources for biological evaluation, leaving their previously isolated or synthesized compounds largely or completely untested. To address this issue, the Canvass library of natural products was assembled, in collaboration with academic and industry researchers, for quantitative high-throughput screening (qHTS) across a diverse set of cell-based and biochemical assays.
View Article and Find Full Text PDFA total synthesis of N-desmethyl thalassospiramide C, a unique strained macrocyclic proteobacterial depsipeptide, enabled a detailed crystallographic study of its covalent complex with cathepsin K, a member of a medicinally important family of cysteine proteases. The study provides support for the mechanism of action, and the insight gained can be used for structure-based drug design targeting these calpain proteases.
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