Breast cancer (BRCA) has become the most common type of cancer in women. Improving the therapeutic response remains a challenge. Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a classic tumour suppressor with emerging new functions discovered in recent years, and myeloid PTEN loss has been reported to impair antitumour immunity. In this study, we revealed a novel mechanism by which myeloid PTEN potentially affects antitumour immunity in BRCA. We detected accelerated stress granule (SG) assembly under oxidative stress in PTEN-deficient bone marrow-derived macrophages (BMDMs) through the EGR1-promoted upregulation of TIAL1 transcription. PI3K/AKT/mTOR (PAM) pathway activation also promoted SG formation. ATP consumption during SG assembly in BMDMs impaired the phagocytic ability of 4T1 cells, potentially contributing to the disruption of antitumour immunity. In a BRCA neoadjuvant cohort, we observed a poorer response in myeloid PTENlow patients with G3BP1 aggregating as SGs in CD68+ cells, a finding that was consistent with the observation in our study that PTEN-deficient macrophages tended to more readily assemble SGs with impaired phagocytosis. Our results revealed the unconventional impact of SGs on BMDMs and might provide new perspectives on drug resistance and therapeutic strategies for the treatment of BRCA patients.
High-dose chemotherapy followed by autologous stem cell transplantation (HDC–ASCT) is a promising approach for patients with primary central nervous system lymphoma (PCNSL). Encouraging results have been reported with thiotepa-based conditioning; however, there is currently no consensus on the optimal conditioning regimens. To improve the tolerance and efficacy of ASCT with thiotepa-based conditioning, this retrospective, single-arm, pilot study was conducted, including 12 PCNSL patients who received ASCT with modified thiotepa-based conditioning regimens. It was found that 6 patients received ASCT as a first-line consolidation in complete response (CR)/partial response (PR) state, and 6 cases underwent salvage treatment. Among the patients, 7 (58.3%) received the mTBC conditioning regimen, 4 (33.3%) received TT-Bu, and one patient was incorporated with chimeric antigen receptor T-cell (CAR-T) cell infusion with the TT-Cy regimen. All patients achieved sustained neutrophil recovery within a median of 9 (range, 7–12) days and platelet engraftment within a median of 10 (range, 6–12) days. Furthermore, all patients were in CR status at the initial efficacy evaluation following ASCT. The main complications during hospitalization were febrile neutropenia (83.3%) and diarrhea grade 3 (50.0%). No transplantation- related mortality occurred. Maintenance therapy post-ASCT was administered in 11 cases, demonstrating its effectiveness and favorable tolerability. The estimated 1- and 3-year progression-free survival (PFS) following ASCT were 80.0% and 53.3%, respectively, while the estimated 1-and 3-year overall survival (OS) were both 100%. This study presented the modified thiotepa-based conditioning regimens and confirmed their safety and efficacy with ASCT for PCNSL patients.
Objective: Analyze the impact of hyperbaric oxygen therapy on neuroprotection and recovery post severe traumatic brain injury (sTBI) resuscitation. Methods: Retrospective analysis of clinical data from 83 sTBI patients admitted between January 2022 to January 2024. Patients were divided into control (n = 41) and observation (n = 42) groups based on treatment received. Control received standard therapy, while the observation group received hyperbaric oxygen therapy. Effects on clinical outcomes, neuroinjury markers (S100β, GFAP, UCH-L1, NSE), neurotrophic factors (NGF, BDNF), neurological function indicators (NIHSS, CSS), and adverse reactions were compared. Results: The observation group showed a higher total effective rate (80.95%) compared to control (60.98%) (P < 0.05). Neuroinjury markers decreased post-treatment in both groups, with the observation group lower (P < 0.05). NGF and BDNF levels increased post-treatment in both groups, with the observation group higher (P < 0.05). NIHSS and CSS scores decreased post-treatment in both groups, with the observation group lower (P < 0.05). No significant difference in adverse reactions between groups (P > 0.05). Conclusion: Hyperbaric oxygen therapy effectively treats sTBI by improving brain resuscitation success, reducing neuroinjury factors, enhancing neurotrophic factors, and promoting neurological function recovery, without increasing adverse reaction risk.
A bivalent inhibitor was uncovered to block the multivalent interactions among stress granules.
PYX-201 is an investigational antibody drug conjugate (ADC) with an engineered, fully human IgG1 antibody, a cleavable chemical linker, and a toxin (Aur0101) with an average drug-antibody ratio (DAR) of similar to 4. A sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated to determine the presence in human plasma, of free payload Aur0101 from PYX-201 to assess drug safety and efficacy. Aur0101 and its deuterated internal standard (IS), Aur0101_d8, were extracted from 25 mu L of human plasma using a solid liquid extraction (SLE) method. Chromatographic analysis was carried out on a Waters Acquity UPLC BEH C18 (2.1 mm x 50 mm, 1.7 mu m, 130 A) column. Quantitation of free Aur0101 was conducted on a Sciex triple quadrupole mass spectrometer API 6500 + using multiple reaction monitoring (MRM) mode via positive electrospray ionization. The calibration curve was linear over the concentration range of 25.0 to 12,500 pg/mL with correlation coefficient, r(2) = 0.9988. The intra-assay %RE was between 4.3% to 14.3% with % CV was = 6.2%. The inter-assay %RE was between 0.2% to 9.5% with % CV was <= 6.1%. The average analyte recovery was 89.7% and the average IS recovery was 88.7%. Aur0101 was found to be stable in human plasma and human whole blood under various tested conditions with and without the presence of PYX-201. To our knowledge, this is the first published fully validated assay for free, unconjugated Aur0101 in any matrix, from any species. This assay has been successfully applied to clinical sample analysis to support clinical studies.
Infectious diseases caused by drug-resistant bacteria bring an increasing threat to public health. Thus, finding an effective approach equipped with a synergistic antibacterial performance becomes a critical challenge. This work reports a NiFe2O4@Au/Polydopamine core/shell nanosphere with rough surface, which exhibits a photothermal and magnetolytic coupling antibacterial behavior. The Au/Polydopamine (Au/PDA) hybrid layer, covered on the stable magnetic NiFe2O4 nanosphere by a one-step polymerization method, possesses an excellent photothermal effect. Simultaneously, the superparamagnetic characteristic offers the NiFe2O4@Au/Polydopamine with fantastic magnetolytic force to the biological organism under a rotating external magnetic field. It is found that the NiFe2O4@Au/PDA core/shell nanospheres show good photothermal antibacterial performance (808 nm laser irradiation) on both Escherichia coli and Staphylococcus aureus. Notably, the photothermal antibacterial performance can be significantly improved under applying the rotating magnetic field. This novel photothermal-magnetolytic coupled antimicrobial method supplies a high performance photothermal bactericidal therapy via a remote conduction and reduces the possible damage to normal tissue caused by overheating. Besides bactericidal therapy, the easily and scalable magnetolytic enhancing method is believed to possess high potential in drug delivery, antitumor, and bioseparation.
Abstract Stress granules (SGs) form through phase separation of biomacromolecules to assist cells in resisting environmental stresses. Numbers of SG proteins contain Arg-Gly-Gly (RGG) motifs, indicating their RNA binding ability, and providing a substrate platform for asymmetric dimethylation of arginine (ADMA), whose roles in SG assembly remain unclear. Here, we demonstrated that Caprin1-mediated recruitment of PRMT1 asymmetrically dimethylates RGGs to provide multiple binding sites for TDRD3, a typical ADMA reader, which in turn bridges the multivalent interactions between RGG motifs and RNA to promote phase separation. This process was suppressed by a bivalent inhibitor of TDRD3, eventually inhibiting proliferation more effectively than arsenite treatment alone. Our work reveals the role of ADMA in SG assembly and the potential of targeting condensates for cancer therapy.
Herein, we report a mild and general nickel-catalysed asymmetric reductive alkylation to effectively convert enamines—a class of important yet underexploited feedstock chemicals—into drug-like α-branched chiral amines and derivatives. This reaction involves the regio- and stereoselective hydrometallation of an enamine to generate a catalytic amount of enantioenriched alkylnickel intermediate, followed by C–C bond formation via alkyl electrophiles.
The Beclin 1-Vps34 complex, known as "mammalian class III PI3K," plays essential roles in membrane-mediated transport processes including autophagy and endosomal trafficking. Beclin 1 acts as a scaffolding molecule for the complex and readily transits from its metastable homodimeric state to interact with key modulators such as Atg14L or UVRAG and form functionally distinct Atg14L/UVRAG-containing Beclin 1-Vps34 subcomplexes. The Beclin 1-Atg14L/UVRAG interaction relies critically on their coiled-coil domains, but the molecular mechanism remains poorly understood. We determined the crystal structure of Beclin 1-UVRAG coiled-coil complex and identified a strengthened interface with both hydrophobic pairings and electrostatically complementary interactions. This structure explains why the Beclin 1-UVRAG interaction is more potent than the metastable Beclin 1 homodimer. Potent Beclin 1-UVRAG interaction is functionally significant because it renders UVRAG more competitive than Atg14L in Beclin 1 binding and is critical for promoting endolysosomal trafficking. UVRAG coiled-coil mutants with weakened Beclin 1 binding do not outcompete Atg14L and fail to promote endolysosomal degradation of the EGF receptor (EGFR). We designed all-hydrocarbon stapled peptides that specifically targeted the C-terminal part of the Beclin 1 coiled-coil domain to interfere with its homodimerization. One such peptide reduced Beclin 1 self-association, promoted Beclin 1-Atg14L/UVRAG interaction, increased autophagic flux, and enhanced EGFR degradation. Our results demonstrate that the targeting Beclin 1 coiled-coil domain with designed peptides to induce the redistribution of Beclin 1 among its self-associated form or Atg14L/UVRAG-containing complexes enhances both autophagy and endolysosomal trafficking.
Ovothiols are thiolhistidine derivatives. The first step of ovothiol biosynthesis is OvoA-catalyzed oxidative coupling between histidine and cysteine. In this report, the remaining steps of ovothiol A biosynthesis were reconstituted in vitro. ETA_14770 (OvoB) was reported as a PLP-dependent sulfoxide lyase, responsible for mercaptohistidine production. OvoA was found to be a bifunctional enzyme, which mediates both oxidative C-S bond formation and methylation of mercaptohistidine to afford ovothiol A. Besides reconstituting the whole biosynthetic pathway, two unique features proposed in the literature were also examined: a potential cysteine-recycling mechanism of the C-S lyase (OvoB) and the selectivity of the π- N methyltransferase.
G4–FA–PEG/DOX with surface-modified PEG and FA and encapsulated DOX showed enhanced in vitro cytotoxicity and cellular uptake via FR-mediated endocytosis.
This article reports a new one-pot method for polymer preparation, which involves double click chemistry. In one pot, two click reactions take place sequentially by adding the reactants step by step. The first click reaction is to produce the monomer for the second click reaction for polymerization. The click polymerization differs from the general click polymerization with the reaction of diazides and dialkynes. Nitrile oxides, produced in situ by the first click reaction of the formation of aldoxime, instead azides, avoiding the poisonousness and explosiveness of azides and being much safer and easy to operate. And 3,5-disubstitute polyisoxazoles are produced by the copper(I)-catalyzed the 1,3-dipolar cycloaddition of nitrile oxides with alkynes in high yields by our one-pot method. The resulting polyisoxazoles agree well with the structural assignment obtained by the 1H NMR and IR analyses, with high molecular weights, narrow molecular weight distribution (Mw/Mn < 1.2) and high regioregularity. The poor solubility of these polymers is found to be caused by their crystallization. Improvement of solubility is achieved by modifying the structures of alkyne monomers. All the polymers are thermally stable, losing little of their weights when heated to approximate to 350 degrees C. (c) 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013, 51, 1645-1650
In an attempt to establish the absolute configuration of meliloester, a natural product isolated from Melilotus alba, the literature structure was synthesized in an enantiopure form. Unexpectedly, the H-1 and C-13 NMR data was completely incompatible with those reported for the natural product. The corresponding m-hydroxy isomer was also excluded as the structure for the natural product.
Cyclodipeptides and their derivatives, the diketopiperazines (DKPs), constitute a large class of secondary metabolites with noteworthy biological activities that are mainly synthesized by microorganisms. The biosynthetic pathways of some DKPs contain cyclodipeptide synthases (CDPSs), a newly defined family of enzymes. CDPSs hijack aminoacyl-tRNAs from their essential role in ribosomal protein synthesis to catalyze the formation of the two peptide bonds of various cyclodipeptides. The aim of the work presented in this thesis manuscript is to characterize the CDPS family. At first, the structural and mechanistic characterization of the first identified CDPS, AlbC of Streptomyces noursei, is presented. Then, the results obtained with three other CDPSs, each of which having suitable properties to increase our understanding of the CDPS family, are described. The CDPS Ndas_1148 of Nocardiopsis dassonvillei extends our knowledge of the molecular bases of the CDPS specificity. The CDPS AlbC-IMI of S. sp. IMI 351155 is a good model to analyze the interaction of each of the two substrates required for the formation of a cyclodipeptide. Finally, the characterization of the CDPS Nvec-CDPS2 from Nematostella vectensis provides the first example of enzymes of animal origin involved in nonribosomal peptide synthesis.
Ion chromatography (IC) is one of the most powerful analysis technologies for the determination of charged compounds. A novel click lysine stationary phase was prepared via Cu(I) catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC) and applied to the analysis of inorganic ions. The chromatographic evaluation demonstrated good performance (e.g. the plate number of thiocyanate is ∼50,000 plates m(-1)) and effective separation ability for the common inorganic anions with aqueous Na(2)SO(4) eluent. The separation mechanism was observed to be mainly dominated by ion exchange interaction. The retention of these analytes is highly dependent on the pH value of eluent. Compared with the lysine stationary phase prepared via the conventional manner, the click lysine exchanger demonstrated shorter retention time and better ion separation characteristics under the same chromatographic conditions, which is a great advantage for rapid separation and analysis of inorganic ions.
Cyclodipeptide synthases (CDPSs) belong to a newly defined family of enzymes that use aminoacyl-tRNAs (aa-tRNAs) as substrates to synthesize the two peptide bonds of various cyclodipeptides, which are the precursors of many natural products with noteworthy biological activities. Here, we describe the crystal structure of AlbC, a CDPS from Streptomyces noursei. The AlbC structure consists of a monomer containing a Rossmann-fold domain. Strikingly, it is highly similar to the catalytic domain of class-I aminoacyl-tRNA synthetases (aaRSs), especially class-Ic TyrRSs and TrpRSs. AlbC contains a deep pocket, highly conserved among CDPSs. Site-directed mutagenesis studies indicate that this pocket accommodates the aminoacyl moiety of the aa-tRNA substrate in a way similar to that used by TyrRSs to recognize their tyrosine substrates. These studies also suggest that the tRNA moiety of the aa-tRNA interacts with AlbC via at least one patch of basic residues, which is conserved among CDPSs but not present in class-Ic aaRSs. AlbC catalyses its two-substrate reaction via a ping-pong mechanism with a covalent intermediate in which L-Phe is shown to be transferred from Phe-tRNA(Phe) to an active serine. These findings provide insight into the molecular bases of the interactions between CDPSs and their aa-tRNAs substrates, and the catalytic mechanism used by CDPSs to achieve the non-ribosomal synthesis of cyclodipeptides.
A class of compounds with a common thiazolo[3,2-a]pyrimidinone motif has been developed as general inhibitors of Bcl-2 family proteins. The lead compound was originally identified in a random screening of a small compound library using a fluorescence polarization-based competitive binding assay. Its binding to the Bcl-x(L) protein was further confirmed by (15)N-HSQC NMR experiments. Structural modifications on the lead compound were guided by the outcomes of molecular modeling studies. Among the 42 compounds obtained, a number of them exhibited much improved binding affinities to Bcl-2 family proteins as compared to the lead compound. The most potent compound, BCL-LZH-40, inhibited the binding of BH3 peptides to Bcl-x(L), Bcl-2, and Mcl-1 with inhibition constants (K(i)) of 17, 534, and 200 nm, respectively.
Cyclodipeptide synthases (CDPSs) are small enzymes structurally related to class-I aminoacyl-tRNA synthetases (aaRSs). They divert aminoacylated tRNAs from their canonical role in ribosomal protein synthesis, for cyclodipeptide formation. All the CDPSs experimentally characterized to date are bacterial. We show here that a predicted CDPS from the sea anemone Nematostella vectensis is an active CDPS catalyzing the formation of various cyclodipeptides, preferentially containing tryptophan. Our findings demonstrate that eukaryotes encode active CDPSs and suggest that all CDPSs have a similar aminoacyl-tRNA synthetase-like architecture and ping-pong mechanism. They also raise questions about the biological roles of the cyclodipeptides produced in bacteria and eukaryotes.