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Clinical Cancer Research : An Official... Jun 2024Patients with glioblastoma (GBM) have a dismal prognosis. While DNA alkylating agent temozolomide (TMZ) is mainstay of chemotherapy, therapeutic resistance develops...
PURPOSE
Patients with glioblastoma (GBM) have a dismal prognosis. While DNA alkylating agent temozolomide (TMZ) is mainstay of chemotherapy, therapeutic resistance develops rapidly in patients. Base excision repair inhibitor TRC102 (methoxyamine) reverses TMZ resistance in preclinical glioma models. We sought to investigate efficacy and safety of oral TRC102+TMZ for recurrent GBM (rGBM).
PATIENTS AND METHODS
A pre-registered (NCT02395692), non-randomized, multicenter, phase 2 clinical trial (BERT) was planned and conducted through the Adult Brain Tumor Consortium (ABTC-1402). Arm 1 included bevacizumab-naïve GBM patients at first recurrence, with primary endpoint of response rates. If sufficient activity was identified, a second arm was planned in bevacizumab-refractory patients. Secondary endpoints were overall survival (OS), progression-free survival (PFS), PFS at six months (PFS-6), and toxicity.
RESULTS
Arm 1 enrolled 19 patients with median of two treatment cycles. Objective responses were not observed, hence, arm 2 did not open. Median OS was 11.1 months (95%CI 8.2-17.9). Median PFS was 1.9 months (95%CI 1.8-3.7). PFS-6 was 10.5% (95%CI 1.3-33.1%). Most toxicities were Grade 1-2, with two Grade 3 lymphopenias and one Grade 4 thrombocytopenia. Two patients with PFS ≥17 months and OS >32 months were deemed 'extended survivors'. RNA sequencing of tumor tissue, obtained at diagnosis, demonstrated significantly enriched signatures of DNA damage response (DDR), chromosomal instability (CIN70, CIN25), and cellular proliferation (PCNA25) in 'extended survivors'.
CONCLUSIONS
These findings confirm safety and feasibility of TRC102+TMZ for rGBM patients. They also warrant further evaluation of combination therapy in biomarker-enriched trials enrolling GBM patients with baseline hyperactivated DDR pathways.
PubMed: 38836759
DOI: 10.1158/1078-0432.CCR-23-4098 -
Organic Letters May 2024A catalytic-condition-controlled synthesis strategy was reported to build quinolizinone and indolizine derivatives from the easily available enamide and triazole...
A catalytic-condition-controlled synthesis strategy was reported to build quinolizinone and indolizine derivatives from the easily available enamide and triazole substrates with high regioselectivity and good functional group tolerance. More especially, this transformation has successfully fulfilled a C-H bond activation of terminal olefin from enamides followed by a [3 + 3] and a [2 + 3] cyclization cascade under different catalytic conditions, respectively, to provide two kinds of potentially biologically active heterocyclic scaffolds with a ring-junction nitrogen atom. Mechanistically, the methoxyamine formyl group serves as either a traceless directing group (DG) or an oxidizing DG via the C-N and C-C cleavage in this protocol.
PubMed: 38767212
DOI: 10.1021/acs.orglett.4c01160 -
Chemical Research in Toxicology Aug 2023Pexidartinib (PEX, TURALIO), a selective and potent inhibitor of the macrophage colony-stimulating factor-1 receptor, has been approved for the treatment of tenosynovial...
Pexidartinib (PEX, TURALIO), a selective and potent inhibitor of the macrophage colony-stimulating factor-1 receptor, has been approved for the treatment of tenosynovial giant cell tumor. However, frequent and severe adverse effects have been reported in the clinic, resulting in a boxed warning on PEX for its risk of liver injury. The mechanisms underlying PEX-related hepatotoxicity, particularly metabolism-related toxicity, remain unknown. In the current study, the metabolic activation of PEX was investigated in human/mouse liver microsomes (HLM/MLM) and primary human hepatocytes (PHH) using glutathione (GSH) and methoxyamine (NHOMe) as trapping reagents. A total of 11 PEX-GSH and 7 PEX-NHOMe adducts were identified in HLM/MLM using an LC-MS-based metabolomics approach. Additionally, 4 PEX-GSH adducts were detected in the PHH. CYP3A4 and CYP3A5 were identified as the primary enzymes responsible for the formation of these adducts using recombinant human P450s and CYP3A chemical inhibitor ketoconazole. Overall, our studies suggested that PEX metabolism can produce reactive metabolites mediated by CYP3A, and the association of the reactive metabolites with PEX hepatotoxicity needs to be further studied.
Topics: Mice; Humans; Animals; Cytochrome P-450 CYP3A; Chromatography, Liquid; Tyrosine Kinase Inhibitors; Tandem Mass Spectrometry; Protein Kinase Inhibitors; Cytochrome P-450 CYP3A Inhibitors; Microsomes, Liver; Metabolomics; Chemical and Drug Induced Liver Injury; Glutathione
PubMed: 37531179
DOI: 10.1021/acs.chemrestox.3c00164 -
Acta Pharmaceutica (Zagreb, Croatia) Jun 2023Methoxamine (Mox) is a well-known α1-adrenoceptor agonist, clinically used as a longer-acting analogue of epinephrine. 1,2-Mox (NRL001) has been also undergoing...
Methoxamine (Mox) is a well-known α1-adrenoceptor agonist, clinically used as a longer-acting analogue of epinephrine. 1,2-Mox (NRL001) has been also undergoing clinical testing to increase the canal resting pressure in patients with bowel incontinence. Here we show, that Mox hydrochloride acts as an inhibitor of base excision repair (BER). The effect is mediated by the inhibition of apurinic/apyrimidinic endonuclease APE1. We link this observation to our previous report showing the biologically relevant effect of Mox on BER - prevention of converting oxidative DNA base damage to double-stranded breaks. We demonstrate that its effect is weaker, but still significant when compared to a known BER inhibitor methoxyamine (MX). We further determined Mox's relative at 19 mmol L, demonstrating a significant effect of Mox on APE1 activity in clinically relevant concentrations.
Topics: Humans; Methoxamine; DNA Repair; Epinephrine; Receptors, Adrenergic; Endonucleases
PubMed: 37307375
DOI: 10.2478/acph-2023-0012 -
Molecular Pharmaceutics Jul 2023Infectious diseases caused by bacterial pathogens are a leading cause of mortality worldwide. In particular, recalcitrant bacterial communities known as biofilms are...
Infectious diseases caused by bacterial pathogens are a leading cause of mortality worldwide. In particular, recalcitrant bacterial communities known as biofilms are implicated in persistent and difficult to treat infections. With a diminishing antibiotic pipeline, new treatments are urgently required to combat biofilm infections. An emerging strategy to develop new treatments is the hybridization of antibiotics. The benefit of this approach is the extension of the useful lifetime of existing antibiotics. The oxazolidinones, which include the last resort antibiotic linezolid, are an attractive target for improving antibiofilm efficacy as they present one of the most recently discovered classes of antibiotics. A key step in the synthesis of new 3-aryl-2-oxazolidinone derivatives is the challenging formation of the oxazolidinone ring. Herein we report a direct synthetic route to the piperazinyl functionalized 3-aryl-2-oxazolidinone . We also demonstrate an application of these piperazine molecules by functionalizing them with a nitroxide moiety as a strategy to extend the useful lifetime of oxazolidinones and improve their potency against Methicillin-resistant (MRSA) biofilms. The antimicrobial susceptibility of the linezolid-nitroxide conjugate and its corresponding methoxyamine derivative (a control for biofilm dispersal) was assessed against planktonic cells and biofilms of MRSA. In comparison to linezolid and our lead compound (a piperazinyl oxazolidinone derivative), the linezolid-nitroxide conjugate displayed a minimum inhibitory concentration that was 4-16-fold higher. The opposite effect was seen in biofilms where the linezolid-nitroxide hybrid was >2-fold more effective (160 μg/mL versus >320 μg/mL) in eradicating MRSA biofilms. The methoxyamine derivative performed on par with linezolid. The drug-likeness of the compounds was also assessed, and all compounds were predicted to have good oral bioavailability. Our piperazinyl oxazolidinone derivative was confirmed to be lead-like and would be a good lead candidate for future functionalized oxazolidinones. The modification of antibiotics with a dispersal agent appears to be a promising approach for eradicating MRSA biofilms and overcoming the antibiotic resistance associated with the biofilm mode of growth.
Topics: Oxazolidinones; Linezolid; Methicillin-Resistant Staphylococcus aureus; Oxindoles; Anti-Bacterial Agents; Microbial Sensitivity Tests; Biofilms
PubMed: 37289102
DOI: 10.1021/acs.molpharmaceut.3c00095 -
Molecules (Basel, Switzerland) May 2023Fenebrutinib is an orally available Bruton tyrosine kinase inhibitor. It is currently in multiple phase III clinical trials for the management of B-cell tumors and...
Fenebrutinib is an orally available Bruton tyrosine kinase inhibitor. It is currently in multiple phase III clinical trials for the management of B-cell tumors and autoimmune disorders. Elementary in-silico studies were first performed to predict susceptible sites of metabolism and structural alerts for toxicities by StarDrop WhichP450™ module and DEREK software; respectively. Fenebrutinib metabolites and adducts were characterized in-vitro in rat liver microsomes (RLM) using MS3 method in Ion Trap LC-MS/MS. Formation of reactive and unstable intermediates was explored using potassium cyanide (KCN), glutathione (GSH) and methoxylamine as trapping nucleophiles to capture the transient and unstable iminium, 6-iminopyridin-3()-one and aldehyde intermediates, respectively, to generate a stable adducts that can be investigated and analyzed using mass spectrometry. Ten phase I metabolites, four cyanide adducts, five GSH adducts and six methoxylamine adducts of fenebrutinib were identified. The proposed metabolic reactions involved in formation of these metabolites are hydroxylation, oxidation of primary alcohol to aldehyde, n-oxidation, and n-dealkylation. The mechanism of reactive intermediate formation of fenebrutinib can provide a justification of the cause of its adverse effects. Formation of iminium, iminoquinone and aldehyde intermediates of fenebrutinib was characterized. N-dealkylation followed by hydroxylation of the piperazine ring is proposed to cause the bioactivation to iminium intermediates captured by cyanide. Oxidation of the hydroxymethyl group on the pyridine moiety is proposed to cause the generation of reactive aldehyde intermediates captures by methoxylamine. N-dealkylation and hydroxylation of the pyridine ring is proposed to cause formation of iminoquinone reactive intermediates captured by glutathione. FBB and several phase I metabolites are bioactivated to fifteen reactive intermediates which might be the cause of adverse effects. In the future, drug discovery experiments utilizing this information could be performed, permitting the synthesis of new drugs with better safety profile. Overall, in silico software and in vitro metabolic incubation experiments were able to characterize the FBB metabolites and reactive intermediates using the multistep fragmentation capability of ion trap mass spectrometry.
Topics: Rats; Animals; Chromatography, Liquid; Chromatography, High Pressure Liquid; Tandem Mass Spectrometry; Piperazines; Pyridones; Glutathione; Cyanides; Aldehydes; Microsomes, Liver
PubMed: 37241965
DOI: 10.3390/molecules28104225 -
Journal of Colloid and Interface Science Sep 2023Recently, quasi two-dimensional (Q-2D) perovskites with alternating cations in the interlayer space (ACI) have attracted more attentions owing to their elevated...
Recently, quasi two-dimensional (Q-2D) perovskites with alternating cations in the interlayer space (ACI) have attracted more attentions owing to their elevated stability compared with three-dimensional (3D) analogs. While the efficiency of the devices derived from Q-2D perovskites is much smaller than that based on 3D perovskites. Here, we utilized urea and methoxyamine hydrochloride (MOAH) dual additives to acquire high quality Q-2D ACI perovskite GA(MA)PbI (GA = guanidinium, MA = methylammonium) films. The efficiency of the perovskite solar cells (PSCs) derived from the Q-2D perovskite films induced by the synergistic effect of urea and MOAH dual additives increases to 20.32% from 17.21% for the devices without additive. This efficiency enhancement could be attributed to the enlarged grain size, improved crystallinity, optimized quantum well thickness distribution, and reduced trap states of the perovskite films. Moreover, the solar cells with dual additives present improved stability. The efficiency of devices with dual additives holds 95% of the original value after storage for 1600 h in ambient air. These results prove that the synergistic effect of urea and MOAH is an effective method to achieve highly efficient and stable Q-2D PSCs.
PubMed: 37235937
DOI: 10.1016/j.jcis.2023.05.132 -
ACS Omega Oct 2022The experiments described here examined the effects of reaction conditions, various additives, and local sequence on the formation and stability interstrand cross-links...
Effects of Local Sequence, Reaction Conditions, and Various Additives on the Formation and Stability of Interstrand Cross-Links Derived from the Reaction of an Abasic Site with an Adenine Residue in Duplex DNA.
The experiments described here examined the effects of reaction conditions, various additives, and local sequence on the formation and stability interstrand cross-links (ICLs) derived from the reaction of an apurinic/apyrimidinic (AP) site with the exocyclic amino group of an adenine residue on the opposing strand in duplex DNA. Cross-link formation was observed in a range of different buffers, with faster formation rates observed at pH 5. Inclusion of the base excision repair enzyme alkyladenine DNA glycosylase (hAAG) which binds tightly to AP-containing duplexes decreased, but did not completely prevent, formation of the dA-AP ICL. Formation of the dA-AP ICL was not altered by the presence of the biological metal ion Mg or the biological thiol, glutathione. Several organocatalysts of imine formation did not enhance the rate of dA-AP ICL formation. Duplex length did not have a large effect on dA-AP yield, so long as the melting temperature of the duplex was not significantly below the reaction temperature (the duplex must remain hybridized for efficient ICL formation). Formation of the dA-AP ICL was examined in over 40 different sequences that varied the neighboring and opposing bases at the cross-linking site. The results indicate that ICL formation can occur in a wide variety of sequence contexts under physiological conditions. Formation of the dA-AP ICL was strongly inhibited by the aldehyde-trapping agents methoxyamine and hydralazine, by NaBHCN, by the intercalator ethidium bromide, and by the minor groove-binding agent netropsin. ICL formation was inhibited to some extent in bicarbonate and Tris buffers. The dA-AP ICL showed substantial inherent stability under a variety of conditions and was not a substrate for AP-processing enzymes APE1 or Endo IV. Finally, we characterized cross-link formation in a small (11 bp) stem-loop (hairpin) structure and in DNA-RNA hybrid duplexes.
PubMed: 36278095
DOI: 10.1021/acsomega.2c05736 -
Metabolites Aug 2022Preterm birth (PTB) is a social problem that adversely affects not only the survival rate of the fetus, but also the premature babies and families, so there is an urgent...
Preterm birth (PTB) is a social problem that adversely affects not only the survival rate of the fetus, but also the premature babies and families, so there is an urgent need to find accurate biomarkers. We noted that among causes, eubiosis of the vaginal microbial community to dysbiosis leads to changes in metabolite composition. In this study, short chain fatty acids (SCFAs) representing dysbiosis were derivatized using (-butyldimethylsilyl--methyltrifluoroacetamide, MTBSTFA) and targeted analysis was conducted in extracted organic phases of cervicovaginal fluid (CVF). In residual aqueous CVF, polar metabolites produced biochemistry process were derivatized using methoxyamine and ,-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and non-targeted analysis were conducted. Nine SCFAs were quantified, and 58 polar metabolites were detected in 90 clinical samples using gas chromatography/mass spectrometry (GC/MS). The criteria of statistical analysis and detection rate of clinical sample for development of PTB biomarkers were presented, and 19 biomarkers were selected based on it, consisting of 1 SCFA, 2 organic acids, 4 amine compounds, and 12 amino acids. In addition, the model was evaluated as a suitable indicator for predicting PTB without distinction between sample collection time. We hope that the developed biomarkers based on microbiota-derived metabolites could provide useful diagnostic biomarkers for actual patients and pre-pregnancy.
PubMed: 36005605
DOI: 10.3390/metabo12080734 -
Analytica Chimica Acta Aug 2022Lipid peroxidation products, such as short chain aldehydes, are powerful biomarkers of oxidative stress, due to the advantage of long lifetime compared to other...
Quality-by-design approach for development of aqueous headspace microextraction GC-MS method for targeted metabolomics of small aldehydes in plasma of cardiovascular patients.
Lipid peroxidation products, such as short chain aldehydes, are powerful biomarkers of oxidative stress, due to the advantage of long lifetime compared to other metabolites of the lipidome. This work proposes an advanced combined derivatization/solvent-less extraction procedure from plasma followed by rapid Gas Chromatography with Mass Spectrometric detection (GC-MS). A new sample pretreatment protocol is presented which is based on a combination of aldehyde derivatization with methoxyamine under fully aqueous-based conditions of diluted plasma samples followed by headspace solid-phase microextraction (HS-SPME) which is faster compared to methods in the literature serving the same purpose. Being the smallest oximation reagent, methoxyamine derivatization does not require a silylation step of hydroxyl groups as customary and made it possible to have the shortest run times for this series of aldehydes by GC-MS. A Response Surface Methodology (RSM) is employed to optimize the HS-SPME of the aldehyde methoximes to provide insights into the Design Space (DS) of HS-SPME of aldehydes of variable chain lengths and unsaturation. The workflow includes a Quality by Design (QbD) approach for optimization of sample microextraction and derivatization methodology under fully aqueous conditions, in contrast to all reported non-aqueous tedious and long extraction methods in the literature followed by development of a rapid GC-MS assay. The optimal sample preparation obtained from the RSM, and multiple linear regression procedure involved addition of 15 mg methoxyamine (CHONH) and 160 mg NaSO to 0.5 mL plasma diluted to 1 mL with water in an extraction vial followed by HS-SPME using Polydimethylsiloxane/Divinylbenzene fiber at 750 rpm and 77 °C for 15 min. The developed HS-SPME-GC-MS method was validated according to FDA guidelines in SIM mode and applied for targeted determination of lipid peroxidation aldehyde metabolites in plasma of 24 cardiovascular patients vs 20 healthy controls. The run time of the GCMS method was less than 15 min and the LOQ of the 10 targeted aldehydes were 0.5 nM for decanal, 5 nM for hexanal, heptanal, octanal, citronellal and citral, 7 nM for malondialdehyde, 35 nM for 4- hydroxynonenal, 105 nM for 4- hydroxyhexenal and 500 nM for glyoxal. Hexanal, Malondialdehyde and Hydroxynonenal concentrations were significantly higher in patients (p-value<0.05) in the targeted study, while citral was significantly lower as obtained from the untargeted study. Reporting an aldehydic profile signature -whether predictive or diagnostic-for cardiovascular patients would support proper medical intervention at the initiation or progression phases of the disease when expanded on larger number of subjects.
Topics: Aldehydes; Gas Chromatography-Mass Spectrometry; Humans; Malondialdehyde; Metabolomics; Solid Phase Microextraction
PubMed: 35934390
DOI: 10.1016/j.aca.2022.340176