Reverse N-Substituted Hydroxamic Acid Derivatives of Fosmidomycin Target a Previously Unknown Subpocket of 1-Deoxy-d-xylulose 5-Phosphate Reductoisomerase (DXR).

Reverse analogs of the phosphonohydroxamic acid antibiotic fosmidomycin are potent inhibitors of the nonmevalonate isoprenoid biosynthesis enzyme 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR, IspC) of Plasmodium falciparum. Some novel analogs with large phenylalkyl substituents at the hydroxamic acid nitrogen exhibit nanomolar PfDXR inhibition and potent in vitro growth inhibition of P. falciparum parasites coupled with good parasite selectivity. X-ray crystallographic studies demonstrated that the N-phenylpropyl substituent of the newly developed lead compound 13e is accommodated in a subpocket within the DXR catalytic domain but does not reach the NADPH binding pocket of the N-terminal domain. As shown for reverse carba and thia analogs, PfDXR selectively binds the S-enantiomer of the new lead compound. In addition, some representatives of the novel inhibitor subclass are nanomolar Escherichia coli DXR inhibitors, whereas the inhibition of Mycobacterium tuberculosis DXR is considerably weaker.

Hydroxamate-Containing Bisphosphonates as Fosmidomycin Analogues: Design, Synthesis, and Proherbicide Activity.

Fosmidomycin (FOS) is a natural product inhibiting the DXR enzyme in the MEP pathway and has stimulated interest for finding more suitable FOS analogues. Herein, two series of FOS analogue hydroxamate-containing bisphosphonates as proherbicides were designed, with bisphosphonate replacing the phosphonic unit in FOS while retaining the hydroxamate (BPF series) or replacing it with retro-hydroxamate (BPRF series). The BPF series were synthesized through a three-step reaction sequence including Michael addition of vinylidenebisphosphonate, N-acylation, and deprotection, and the BPRF series were synthesized with a retro-Claisen condensation incorporated into the reaction sequence. Evaluation on model plants demonstrated several compounds having considerable herbicidal activities, and in particular, compound 8m exhibited multifold activity enhancement as compared to the control FOS. The proherbicide properties were comparatively validated. Furthermore, DXR enzyme assay, dimethylallyl pyrophosphate rescue, and molecular docking verified 8m to be a promising proherbicide candidate targeting the DXR enzyme. In addition, 8m also displayed good antimalarial activities.

Exploration of potential hit compounds targeting 1-deoxy-d-xylulose 5-phosphate reductoisomerase (IspC) from Acinetobacter baumannii: an in silico investigation.

The emergence of carbapenem-resistant Acinetobacter baumannii, a highly concerning bacterial species designated as a Priority 1: Critical pathogen by the WHO, has become a formidable global threat. In this study, we utilised computational methods to explore the potent molecules capable of inhibiting the IspC enzyme, which plays a crucial role in the methylerythritol 4-phosphate (MEP) biosynthetic pathway. Employing high-throughput virtual screening of small molecules from the Enamine library, we focused on the highly conserved substrate binding site of the DXR target protein, resulting in the identification of 1000 potential compounds. Among these compounds, we selected the top two candidates (Z2615855584 and Z2206320703) based on Lipinski's rule of Five and ADMET filters, along with FR900098, a known IspC inhibitor, and DXP, the substrate of IspC, for molecular dynamics (MD) simulations. The MD simulation trajectories revealed remarkable structural and thermodynamic stability, as well as strong binding affinity, for all the IspC-ligand complexes. Furthermore, binding free energy calculations based on MM/PBSA (Molecular Mechanics/Poisson-Boltzmann Surface Area) methodology demonstrated significant interactions between the selected ligand molecules and IspC. Taking into consideration all the aforementioned criteria, we suggest Z2206320703 as the potent lead candidate against IspC. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-024-03923-w.

RL2 Enhances the Elimination of Breast Cancer Cells by Doxorubicin.

RL2 (recombinant lactaptin 2), a recombinant analogon of the human milk protein Κ-Casein, induces mitophagy and cell death in breast carcinoma cells. Furthermore, RL2 was shown to enhance extrinsic apoptosis upon long-term treatment while inhibiting it upon short-term stimulation. However, the effects of RL2 on the action of chemotherapeutic drugs that induce the intrinsic apoptotic pathway have not been investigated to date. Here, we examined the effects of RL2 on the doxorubicin (DXR)-induced cell death in breast cancer cells with three different backgrounds. In particular, we used BT549 and MDA-MB-231 triple-negative breast cancer (TNBC) cells, T47D estrogen receptor alpha (ERα) positive cells, and SKBR3 human epidermal growth factor receptor 2 (HER2) positive cells. BT549, MDA-MB-231, and T47D cells showed a severe loss of cell viability upon RL2 treatment, accompanied by the induction of mitophagy. Furthermore, BT549, MDA-MB-231, and T47D cells could be sensitized towards DXR treatment with RL2, as evidenced by loss of cell viability. In contrast, SKBR3 cells showed almost no RL2-induced loss of cell viability when treated with RL2 alone, and RL2 did not sensitize SKBR3 cells towards DXR-mediated loss of cell viability. Bioinformatic analysis of gene expression showed an enrichment of genes controlling metabolism in SKBR3 cells compared to the other cell lines. This suggests that the metabolic status of the cells is important for their sensitivity to RL2. Taken together, we have shown that RL2 can enhance the intrinsic apoptotic pathway in TNBC and ERα-positive breast cancer cells, paving the way for the development of novel therapeutic strategies.

Design, Synthesis and Bioactivity Evaluation of Heterocycle-Containing Mono- and Bisphosphonic Acid Compounds.

Fosmidomycin (FOS) is a naturally occurring compound active against the 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) enzyme in the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, and using it as a template for lead structure design is an effective strategy to develop new active compounds. In this work, by replacing the hydroxamate unit of FOS with pyrazole, isoxazole and the related heterocycles that also have metal ion binding affinity, while retaining the monophosphonic acid in FOS or replacing it with a bisphosphonic acid group, heterocycle-containing mono- and bisphosphonic acid compounds as FOS analogs were designed. The key steps involved in the facile synthesis of these FOS analogs included the Michael addition of diethyl vinylphosphonate or tetraethyl vinylidenebisphosphonate to ß-dicarbonyl compounds and the subsequent cyclic condensation with hydrazine or hydroxylamine. Two additional isoxazolinone-bearing FOS analogs were synthesized via the Michaelis-Becker reaction with diethyl phosphite as a key step. The bioactivity evaluation on model plants demonstrated that several compounds have better herbicidal activities compared to FOS, with the most active compound showing a 3.7-fold inhibitory activity on Arabidopsis thaliana, while on the roots and stalks of Brassica napus L. and Echinochloa crus-galli in a pre-emergence inhibitory activity test, the activities of this compound were found to be 3.2- and 14.3-fold and 5.4- and 9.4-fold, respectively, and in a post-emergency activity test on Amaranthus retroflexus and Echinochloa crus-galli, 2.2- and 2.0-fold inhibition activities were displayed. Despite the significant herbicidal activity, this compound exhibited a DXR inhibitory activity lower than that of FOS but comparable to that of other non-hydroxamate DXR inhibitors, and the dimethylallyl pyrophosphate rescue assay gave no statistical significance, suggesting that a different target might be involved in the inhibiting process. This work demonstrates that using bioisosteric replacement can be considered as a valuable strategy to discover new FOS analogs that may have high herbicidal activities.

Cloning and functional analysis of the DXR gene and promoter region in Osmanthus fragrans var. semperflorens.

The precise biological function and activity of the deoxylulose-5-phosphate reductoisomerase (DXR) gene and its promoter in Osmanthus fragrans var. semperflorens remain unclear, even though OfDXR is known as the crucial enzyme involved in plant terpenoid synthesis. This study aimed to shed light on the role and activity of the OfDXR gene and its promoter in O. fragrans var. semperflorens by employing RACE-PCR and Hi-TAIL-PCR techniques for the cloning of the gene and promoter sequence from the petal tissue. Subsequently, genetic transformation and histochemical staining methods were utilized to analyze their function and activity. The OfDXR gene exhibited a DNA sequence length of 5241 bp, encompassing 12 exons and 11 introns. The corresponding cDNA sequence of the OfDXR gene was 1629 bp, encoding 474 amino acid residues. Expression analysis revealed that the OfDXR gene was predominantly active in the petals during the early full blooming stage. Overexpression of the OfDXR gene in Arabidopsis plants at the primary or full blooming stage led to an augmentation in the total terpenoid content. Furthermore, the promoter sequence of the OfDXR gene spanned a length of 1174 bp and contained conserved regulatory/response elements, demonstrating functional activity. These findings indicate that the OfDXR gene plays a pivotal role in terpenoid synthesis, while its promoter exhibits robust activity.

MEPicides: α,ß-unsaturated Fosmidomycin N-Acyl Analogs as Efficient Inhibitors of Plasmodium falciparum 1-Deoxy-d-xylulose-5-phosphate reductoisomerase.

Malaria, a mosquito-borne disease caused by several parasites of the Plasmodium genus, remains a huge threat to global public health. There are an estimated 0.5 million malaria deaths each year, mostly among African children. Unlike humans, Plasmodium parasites and a number of important pathogenic bacteria employ the methyl erythritol phosphate (MEP) pathway for isoprenoid synthesis. Thus, the MEP pathway represents a promising set of drug targets for antimalarial and antibacterial compounds. Here, we present new unsaturated MEPicide inhibitors of 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), the second enzyme of the MEP pathway. A number of these compounds have demonstrated robust inhibition of Plasmodium falciparum DXR, potent antiparasitic activity, and low cytotoxicity against HepG2 cells. Parasites treated with active compounds are rescued by isopentenyl pyrophosphate, the product of the MEP pathway. With higher levels of DXR substrate, parasites acquire resistance to active compounds. These results further confirm the on-target inhibition of DXR in parasites by the inhibitors. Stability in mouse liver microsomes is high for the phosphonate salts, but remains a challenge for the prodrugs. Taken together, the potent activity and on-target mechanism of action of this series further validate DXR as an antimalarial drug target and the α,ß-unsaturation moiety as an important structural component.

Dingxin recipe â ¢ ameliorates hyperlipidemia injury in SD rats by improving the gut barrier, particularly the SCFAs/GPR43 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Dingxin Recipe Ⅲ (DXR Ⅲ) is a traditional Chinese medicine compound used for hyperlipidemia treatment in clinical practice. However, its curative effects and pharmacological mechanisms in hyperlipidemia have not been clarified to date. AIM OF THE STUDY: Studies have demonstrated that gut barrier was strongly implicated in lipid deposition. Based on gut barrier and lipid metabolism, this study examined the effects and molecular mechanisms of DXR Ⅲ in hyperlipidemia. MATERIALS AND METHODS: The bioactive compounds of DXR Ⅲ were detected by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and its effects were evaluated in high-fat diet-fed rats. Specifically, the serum levels of lipids and hepatic enzymes were measured using the appropriate kits; colon and liver sections were obtained for histological analyses; gut microbiota and metabolites were analyzed by 16S rDNA sequencing and liquid chromatography-MS/MS; and the expression of genes and proteins was determined by real-time quantitative polymerase chain reaction and western blotting and immunohistochemistry, respectively. The pharmacological mechanisms of DXR Ⅲ were further explored by fecal microbiota transplantation and short-chain fatty acid (SCFAs)-based interventions. RESULTS: DXR Ⅲ treatment significantly downregulated serum lipid levels, mitigated hepatocyte steatosis and improved lipid metabolism. Moreover, DXR Ⅲ improved the gut barrier, specifically by improving the physical barrier in the colon, causing part composition changes in the gut microbiota, and increasing the serum SCFAs level. DXR Ⅲ also upregulated the expression of colon GPR43/GPR109A. Fecal microbiota transplantation from rats treated with DXR Ⅲ downregulated part hyperlipidemia-related phenotypes, while the SCFAs intervention significantly improved most of the hyperlipidemia-related phenotypes and upregulated the expression of GPR43. Moreover, both DXR Ⅲ and SCFAs upregulated the expression of colon ABCA1. CONCLUSION: DXR Ⅲ protects against hyperlipidemia by improving the gut barrier, particularly the SCFAs/GPR43 pathway.

Over 40 Years of Fosmidomycin Drug Research: A Comprehensive Review and Future Opportunities.

To address the continued rise of multi-drug-resistant microorganisms, the development of novel drugs with new modes of action is urgently required. While humans biosynthesize the essential isoprenoid precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) via the established mevalonate pathway, pathogenic protozoa and certain pathogenic eubacteria use the less well-known methylerythritol phosphate pathway for this purpose. Important pathogens using the MEP pathway are, for example, Plasmodium falciparum, Mycobacterium tuberculosis, Pseudomonas aeruginosa and Escherichia coli. The enzymes of that pathway are targets for antiinfective drugs that are exempt from target-related toxicity. 2C-Methyl-D-erythritol 4-phosphate (MEP), the second enzyme of the non-mevalonate pathway, has been established as the molecular target of fosmidomycin, an antibiotic that has so far failed to be approved as an anti-infective drug. This review describes the development and anti-infective properties of a wide range of fosmidomycin derivatives synthesized over the last four decades. Here we discuss the DXR inhibitor pharmacophore, which comprises a metal-binding group, a phosphate or phosphonate moiety and a connecting linker. Furthermore, non-fosmidomycin-based DXRi, bisubstrate inhibitors and several prodrug concepts are described. A comprehensive structure-activity relationship (SAR) of nearly all inhibitor types is presented and some novel opportunities for further drug development of DXR inhibitors are discussed.

Isoprenoid biosynthesis regulation in poplars by methylerythritol phosphate and mevalonic acid pathways.

It is critical to develop plant isoprenoid production when dealing with human-demanded industries such as flavoring, aroma, pigment, pharmaceuticals, and biomass used for biofuels. The methylerythritol phosphate (MEP) and mevalonic acid (MVA) plant pathways contribute to the dynamic production of isoprenoid compounds. Still, the cross-talk between MVA and MEP in isoprenoid biosynthesis is not quite recognized. Regarding the rate-limiting steps in the MEP pathway through catalyzing 1-deoxy-D-xylulose5-phosphate synthase and 1-deoxy-D-xylulose5-phosphate reductoisomerase (DXR) and also the rate-limiting step in the MVA pathway through catalyzing 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), the characterization and function of HMGR from Populus trichocarpa (PtHMGR) were analyzed. The results indicated that PtHMGR overexpressors (OEs) displayed various MEP and MVA-related gene expressions compared to NT poplars. The overexpression of PtDXR upregulated MEP-related genes and downregulated MVA-related genes. The overexpression of PtDXR and PtHMGR affected the isoprenoid production involved in both MVA and MEP pathways. Here, results illustrated that the PtHMGR and PtDXR play significant roles in regulating MEP and MVA-related genes and derived isoprenoids. This study clarifies cross-talk between MVA and MEP pathways. It demonstrates the key functions of HMGR and DXR in this cross-talk, which significantly contribute to regulate isoprenoid biosynthesis in poplars.

Transcriptomic profiling of the floral fragrance biosynthesis pathway of Liriodendron and functional characterization of the LtuDXR gene.

Floral fragrance, which has the function of attracting pollinators, is a class of volatile secondary metabolites mainly released by the secretory tissue of petals. Terpenoids are key components of floral volatile substances. Previous studies have shown that there are significant differences in the concentration and composition of volatile floral fragrances, especially terpenoids, between Liriodendron chinense and L. tulipifera. At present, the mechanism by which the synthesis of floral fragrance is regulated in Liriodendron remains unexplored. In this study, we analyzed the differentially expressed genes (DEGs) of L. chinense and L. tulipifera, and identified 130 DEGs related to terpenoid synthesis. A KEGG enrichment analysis of DEGs related to terpenoid biosynthesis revealed that the monoterpenoid biosynthesis pathway was the most significant. We cloned the LtuDXR gene from L. tulipifera using RACE technology. RT-qPCR results showed that the expression of the LtuDXR gene was the highest in the early florescence petals, indicating that the LtuDXR gene may play a role in the synthesis of volatile terpenoids. Subcellular localization showed that the LtuDXR protein is mainly localized in the chloroplast. Overexpression of LtuDXR in Arabidopsis thaliana significantly increased the plant height, DXR enzyme activity, and carotenoid content. In this study, we identified and functionally characterized LtuDXR, which is involved in terpenoid synthesis in Liriodendron. Our work lays the foundation for further exploration of the molecular mechanism by which terpenoid biosynthesis is regulated in Liriodendron.

α,α-Difluorophosphonohydroxamic Acid Derivatives among the Best Antibacterial Fosmidomycin Analogues.

Three α,α-difluorophosphonate derivatives of fosmidomycin were synthesized from diethyl 1,1-difluorobut-3-enylphosphonate and were evaluated on Escherichia coli. Two of them are among the best 1-deoxy-d-xylulose 5-phosphate reductoisomerase inhibitors, with IC50 in the nM range, much better than fosmidomycin, the reference compound. They also showed an enhanced antimicrobial activity against E. coli on Petri dishes in comparison with the corresponding phosphates and the non-fluorinated phosphonate.

CircPRDM2 Contributes to Doxorubicin Resistance of Osteosarcoma by Elevating EZH2 via Sponging miR-760.

BACKGROUND: Circular RNAs (circRNAs) are implicated in the chemoresistance of human cancers. However, the functions of circRNA PR/SET domain 2 (circPRDM2) in the resistance of osteosarcoma (OS) to doxorubicin (DXR) are unknown. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) assay was conducted to determine the levels of circPRDM2, microRNA-760 (miR-760) and enhancer of zeste homolog 2 (EZH2). RNase R assay was used to analyze the characteristics of circPRDM2. IC50 of DXR was estimated by Cell Counting Kit-8 (CCK-8) assay. Colony formation assay was performed for cell colony formation ability. Wound-healing assay and transwell assay were utilized for cell migration and invasion. Flow cytometry analysis was conducted for cell apoptosis. Western blot assay was employed for protein levels. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay were adopted to analyze the relationships among circPRDM2, miR-760 and EZH2. Murine xenograft model assay was utilized to explore DXR resistance in vivo. RESULTS: CircPRDM2 level was enhanced in DXR-resistant OS tissues and cells. CircPRDM2 deficiency inhibited IC50 of DXR, colony formation, migration and invasion and facilitated apoptosis in DXR-resistant OS cells in vitro. CircPRDM2 was identified as the sponge for miR-760. MiR-760 inhibition reversed the inhibitory effects of circPRDM2 knockdown on DXR resistance and cell progression in DXR-resistant OS cells. Moreover, EZH2 was identified as the target gene of miR-760 and EZH2 overexpression abolished miR-760-mediated impacts on DXR sensitivity and malignant behaviors in DXR-resistant OS cells. Also, circPRDM2 silencing improved DXR sensitivity in vivo. CONCLUSION: Our study demonstrated the role of circPRDM2/miR-760/EZH2 axis in enhancing DXR resistance.

In silico characterization and differential expression analysis of 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR) of Centella asiatica.

The 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR; EC1.1.1.267), an NADPH-dependent reductase, plays a pivotal role in the methylerythritol 4-phosphate pathway (MEP), in the conversion of 1-deoxy-d-xylulose-5-phosphate (DXP) into MEP. Photochemical profiles, as well as pharmaceutical activities of Centella asiatica (L.), one of the most valuable medicinal plants, divulge the presence of secondary metabolites called Centellosides. Despite well-studied pharmaceutical activities, not much is known about the genes responsible for the synthesis of these compounds. In the present study, the full-length DXR gene sequence (JQ965955) of Centella submitted in NCBI was characterized using various bioinformatics tools and tissue specific differential expression studies were also carried out. The full-length CDNA of CaDXR contains an open reading frame (ORF) of 1425 bp which encodes a peptide of 474 amino acids. The molecular weight of this protein was found to be 51.5 kDa with isoelectric point of 6.33. The protein contains three conserved domain, namely NADPH (GSTGSIGT and LAAGSNV), substrate binding (LPADSEHSAI and NKGLEVIEAHY) and Cys-Ser-(Ala/Met/Val/Thr) cleavage-site domains. Phylogenetic studies of CaDXR sequence show close homology with DXR sequence of Angelica sinensis and Daucus carota subsp sativus as they all belong to Apiaceae family. In silico analysis predicted that CaDXR protein contains 21 α-helix and 11 ß-sheets and further DXR protein model was validated by Ramachandran plot analysis. The results of molecular dynamics (MD) simulations unveil dynamic stability of the proposed model and docking studies suggest that the NDP cofactor tightly binds in the active site of the protein with a strong network of hydrogen and hydrophobic interactions. The expression studies by semi-RT followed by qRT-PCR suggests that CaDXR is differentially expressed in different tissues (with maximal expression in the node and lowest in the roots). Thus, characterization and structure-function analysis of DXR gene in Centella facilitate us to understand not only the functions of DXR gene but also regulatory mechanisms involved in the MEP pathway in C. asiatica plant at the molecular level. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02723-w.

Identification of potential therapeutic target of naringenin in breast cancer stem cells inhibition by bioinformatics and in vitro studies.

Cancer therapy is a strategic measure in inhibiting breast cancer stem cell (BCSC) pathways. Naringenin, a citrus flavonoid, was found to increase breast cancer cells' sensitivity to chemotherapeutic agents. Bioinformatics study and 3D tumorsphere in vitro modeling in breast cancer (mammosphere) were used in this study, which aims to explore the potential therapeutic targets of naringenin (PTTNs) in inhibiting BCSCs. Bioinformatic analyses identified direct target proteins (DTPs), indirect target proteins (ITPs), naringenin-mediated proteins (NMPs), BCSC regulatory genes, and PTTNs. The PTTNs were further analyzed for gene ontology, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, protein-protein interaction (PPI) networks, and hub protein selection. Mammospheres were cultured in serum-free media. The effects of naringenin were measured by MTT-based cytotoxicity, mammosphere forming potential (MFP), colony formation, scratch wound-healing assay, and flow cytometry-based cell cycle analyses and apoptosis assays. Gene expression analysis was performed using real-time quantitative polymerase chain reaction (q-RT PCR). Bioinformatics analysis revealed p53 and estrogen receptor alpha (ERα) as PTTNs, and KEGG pathway enrichment analysis revealed that TGF-ß and Wnt/ß-catenin pathways are regulated by PTTNs. Naringenin demonstrated cytotoxicity and inhibited mammosphere and colony formation, migration, and epithelial to mesenchymal transition in the mammosphere. The mRNA of tumor suppressors P53 and ERα were downregulated in the mammosphere, but were significantly upregulated upon naringenin treatment. By modulating the P53 and ERα mRNA, naringenin has the potential of inhibiting BCSCs. Further studies on the molecular mechanism and formulation of naringenin in BCSCs would be beneficial for its development as a BCSC-targeting drug.

Non-hydroxamate inhibitors of 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR): A critical review and future perspective.

1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) catalyzes the second step of the non-mevalonate (or MEP) pathway that functions in several organisms and plants for the synthesis of isoprenoids. DXR is essential for the survival of multiple pathogenic bacteria/parasites, including those that cause tuberculosis and malaria in humans. DXR function is inhibited by fosmidomycin (1), a natural product, which forms a chelate with the active site divalent metal (Mg2+/Mn2+) through its hydroxamate metal-binding group (MBG). Most of the potent DXR inhibitors are structurally similar to 1 and retain hydroxamate despite the unfavourable pharmacokinetic and toxicity profile of the latter. We provide our perspective on the lack of non-hydroxamate DXR inhibitors. We also highlight the fundamental flaws in the design of MBG in these molecules, primarily responsible for their failure to inhibit DXR. We also suggest that for designing next-generation non-hydroxamate DXR inhibitors, approaches followed for other metalloenzymes targets may be exploited.

Decrease of the DXR-induced genotoxicity and nongenotoxic effects of Theobroma cacao revealed by micronucleus assay / Diminuição da genotoxicidade induzida por DXR e efeitos não genotóxicos de Theobroma cacao revelados pelo ensaio de micronúcleo

This study evaluated the genotoxicity of lyophilized glycolic extract of Theobroma cacao Linné seeds (TCL), using the micronucleus assay in bone marrow of mice. The interaction between TCL and doxorubicin (DXR) was also analyzed. Experimental groups were evaluated 24-48 h after treatment with N-Nitroso-N-ethylurea (NEU: 50 mg/kg), DXR (5 mg/kg), NaCl (145 mM), TCL (0.5-2 g/kg), and TCL (2 g/kg) in combination with DXR (antigenotoxic assays). Analysis of micronucleated polychromatic erythrocytes (MNPCEs) showed no significant differences between all the treatment doses of TCL and NaCl control. Mice experimentally treated with DXR and NEU significantly induced MNPCEs. However, a significant reduction of MNPCEs was also observed when TCL was administered in combination with the chemotherapeutic agent DXR. The analysis of the PCE/NCE ratio revealed no significant differences between the NaCl control, all doses of TCL, and DXR. However, there were significant differences in the PCE/NCE ratio between positive NEU control and all other treatments. The PCE/NCE ratio observed after treatment with TCL and DXR showed significant differences and intermediate values to controls (NaCl and NEU). This study suggests absence of genotoxicity and cytotoxicity of TCL, regardless of dose, sex, and time. TCL reduced genotoxic effects induced by DXR, suggesting potential antigenotoxic effects.

Este estudo avaliou a genotoxicidade do extrato glicólico liofilizado de sementes de Theobroma cacao Linné (TCL), usando o ensaio do micronúcleo em medula óssea de camundongos. A interação entre TCL e doxorrubicina (DXR) foi também analisada. Grupos experimentais foram avaliados 24-48 h após tratamento com N-Nitroso-N-etilureia (NEU: 50 mg/kg), DXR (5 mg/kg), NaCl (145 mM), TCL (0,5-2 g/kg), e TCL (2 g/kg) em combinação com DXR (ensaio antigenotóxico). As análises de eritrócitos policromáticos micronucleados (EPCMNs) não mostraram diferenças significantes entre todas as doses de tratamento do TCL e o controle NaCl. Camundongos experimentalmente tratados com DXR e NEU induziram significativamente EPCMNs. Contudo, uma redução significante de EPCMNs foi também observada quando TCL foi administrada em combinação com o agente quimioterapêutico DXR. As análises da relação EPC/ENC (eritrócito policromático/eritrócito normocromático) revelaram ausência de diferenças significantes entre o controle NaCl, todas as doses de TCL e DXR. Contudo, houve diferenças significantes na relação EPC/ENC entre o controle positivo NEU e todos os outros tratamento. A relação ECP/ENC observada após o tratamento com TCL e DXR mostrou diferenças significantes e valores intermediários aos controles (NaCl e NEU). Este estudo sugere ausência de genotoxicidade e citotoxicidade de TCL, independentemente da dose, sexo e tempo. TCL reduziu os efeitos genotóxicos induzidos por DXR, sugerindo potencial efeitos antigenotóxicos.

Efficacy and Safety of Dual-Drug-Eluting Stents for de Novo Coronary Lesions in South Korea-The Effect Trial.

BACKGROUND: Drug-eluting stents (DESs) are commonly used in percutaneous coronary intervention (PCI) procedures; however, complications including in-stent restenosis and stent thrombosis are significant challenges. The dual-DES is a stent that elutes two drugs to target various stages of the restenosis reaction. This study investigated the safety and efficacy of dual-DES in clinical practice. METHODS: This study included 375 patients who underwent PCI with Cilotax™ or DXR™ dual-DESs at one of 13 centers in South Korea. The primary endpoint was target lesion failure (TLF) within 1 year. The secondary endpoints were cardiac death, myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis. RESULTS: The rates of TLF in dual-DESs (3.7%) were comparable to those reported in conventional DES. In addition, the DXR™ group had a significantly lower rate of TLF than the Cilotax™ group. In multivariate analysis, the DXR™ group had a lower risk of TLF (adjusted hazard ratio (HR) 0.30, 95% CI 0.09-0.92, p = 0.036) and MI (adjusted HR 0.16, 95% CI 0.03-0.82, p = 0.027) than the Cilotax™ group. CONCLUSION: Dual-DESs had similar clinical outcomes regarding efficacy and safety as conventional DES. Among the dual-DES, the DXR™ stent as a new generation dual-DES had more favorable clinical outcomes than the Cilotax™ stent.

Adjuvant Antitumor Immunity Contributes to the Overall Antitumor Effect of Pegylated Liposomal Doxorubicin (Doxil®) in C26 Tumor-Bearing Immunocompetent Mice.

Doxorubicin (DXR) has been reported to have direct cytotoxicity against cancer cells and indirect immunotoxicity by modulation of host antitumor immunity. Hence, it may prevent cancer progression by a dual mechanism. Doxil®, a formulation of DXR encapsulated in polyethylene glycol modified (PEGylated) liposomes, is the most widely used of the clinically approved liposomal anticancer drugs. However, the effect of Doxil® on host antitumor immunity is not well understood. In this study, Doxil® efficiently suppressed tumor growth in immunocompetent mice bearing C26 murine colorectal carcinomas, but not in T cell-deficient nude mice, indicating a contribution of T cells to the overall antitumor effect of Doxil®. In immunocompetent mice, Doxil® increased major histocompatibility complex (MHC-1) levels in C26 tumors, which may be an indicator of increased immunogenicity of tumor cells, and potentially amplified tumor immunogenicity by decreasing immunosuppressive cells such as regulatory T cells, tumor-associated microphages and myeloid-derived suppressor cells that collectively suppress T cell-mediated antitumor responses. This suggests that encapsulation of DXR into PEGylated liposomes increased the therapeutic efficacy of DXR though effects on host antitumor immunogenicity in addition to direct cytotoxic effects on tumor cells. This report describes the role of host antitumor immunity in the overall therapeutic effects of Doxil®. Manipulating pharmacokinetics and biodistribution of chemotherapeutic agents with immunomodulatory properties may increase their therapeutic efficacies by amplifying host antitumor immunity in addition to direct cytotoxic effects on tumor cells.

Projected lung areas using dynamic X-ray (DXR).

BACKGROUND: Dynamic X-ray (DXR) provides images of multiple phases of breath with less radiation exposure than CT. The exact images at end-inspiratory or end-expiratory phases can be chosen accurately. PURPOSE: To investigate the correlation of the projected lung area (PLA) by dynamic chest X-ray with pulmonary functions. MATERIAL AND METHODS: One hundred sixty-two healthy volunteers who received medical check-ups for health screening were included in this study. All subjects underwent DXR in both posteroanterior (PA) and lateral views and pulmonary function tests on the same day. All the volunteers took several tidal breaths before one forced breath as instructed. The outlines of lungs were contoured manually on the workstation with reference to the motion of diaphragm and the graph of pixel values. The PLAs were calculated automatically, and correlations with pulmonary functions and demographic data were analyzed statistically. RESULTS: The PLAs have correlation with physical characteristics, including height, weight and BMI, and pulmonary functions such as vital capacity (VC) and forced expiratory volume in one second (FEV1). VC and FEV1 revealed moderate correlation with the PLAs of PA view in forced inspiratory phase (VC: right, r = 0.65; left, r = 0.69. FEV1: right, r = 0.54; left, r = 0.59). Multivariate analysis showed that body mass index (BMI), sex and VC were considered independent correlation factors, respectively. CONCLUSION: PLA showed statistically significant correlation with pulmonary functions. Our results indicate DXR has a possibility to serve as an alternate method for pulmonary function tests in subjects requiring contact inhibition including patients with suspected or confirmed covid-19.