The large and rapid increase in the incidence and mortality of colorectal cancer (CRC) demonstrates the urgent need for new drugs with higher efficacy to treat CRC. However, the lack of applicable and reliable preclinical models significantly hinders the progress of drug development. Patient-derived xenograft (PDX) models are currently considered reliable in vivo preclinical models for predicting drug efficacy in cancer patients.
View Article and Find Full Text PDFJ Med Chem
December 2024
Methylenetetrahydrofolate dehydrogenase/cyclohydrolase 2 (MTHFD2), a pivotal mitochondrial enzyme in one-carbon metabolism, is significantly upregulated in various cancers but minimally expressed in normal proliferating cells. In contrast, MTHFD1, which performs similar functions, is predominantly expressed in normal cells. Therefore, targeting MTHFD2 with selective inhibitors holds promise for a broader therapeutic window with reduced toxicity and fewer side effects.
View Article and Find Full Text PDFIndoleamine 2,3-dioxygenase-1 (IDO1) is a potential target for the next generation of cancer immunotherapies. We describe the development of two series of IDO1 inhibitors incorporating a N-hydroxy-thiophene-carboximidamide core generated by knowledge-based drug design. Structural modifications to improve the cellular activity and pharmacokinetic (PK) properties of the compounds synthesized, including extension of the side chain of the N-hydroxythiophene-2-carboximidamide core, resulted in compound 27a, a potent IDO1 inhibitor which demonstrated significant (51%) in vivo target inhibition on IDO1 in a human SK-OV-3 ovarian xenograft tumor mouse model.
View Article and Find Full Text PDFMethylenetetrahydrofolate dehydrogenase 2 (MTHFD2) plays an important role in one-carbon metabolism. The MTHFD2 gene is upregulated in various cancers but very low or undetectable in normal proliferating cells, and therefore a potential target for cancer treatment. In this study, we present the structure of MTHFD2 in complex with xanthine derivative , which allosterically binds to MTHFD2 and coexists with the substrate analogue.
View Article and Find Full Text PDFIEEE Trans Neural Netw Learn Syst
November 2022
Underwater image processing has been shown to exhibit significant potential for exploring underwater environments. It has been applied to a wide variety of fields, such as underwater terrain scanning and autonomous underwater vehicles (AUVs)-driven applications, such as image-based underwater object detection. However, underwater images often suffer from degeneration due to attenuation, color distortion, and noise from artificial lighting sources as well as the effects of possibly low-end optical imaging devices.
View Article and Find Full Text PDFIEEE Trans Image Process
December 2019
Images/videos captured from outdoor visual devices are usually degraded by turbid media, such as haze, smoke, fog, rain, and snow. Haze is the most common one in outdoor scenes due to the atmosphere conditions. In this paper, a novel deep learning-based architecture (denoted by MSRL-DehazeNet) for single image haze removal relying on multi-scale residual learning (MSRL) and image decomposition is proposed.
View Article and Find Full Text PDFAim: To examine the accuracy of machine learning to relate particulate matter (PM) 2.5 and PM10 concentrations to upper respiratory tract infections (URIs).
Methods: Daily nationwide and regional outdoor PM2.
ACS Appl Mater Interfaces
January 2018
Titanium (Ti) has high potential in many practical applications such as biomedicine, architecture, aviation, and energy. In this study, we demonstrate an innovative application of dye-sensitized solar cells (DSSCs) based on Ti photoanodes that can be integrated into the roof engineering of large-scale architectures. A chromatic Ti foil produced by anodizing oxidation (coloring) technology is an attractive roof material for large-scale architecture, showing a colorful appearance due to the formation of a reflective TiO thin layer on both surfaces of Ti.
View Article and Find Full Text PDFFree Radic Biol Med
December 2017
Nuclear factor erythroid-2-related factor 2 (NRF2) mainly regulates transcriptional activation through antioxidant-responsive elements (AREs) present in the promoters of NRF2 target genes. Recently, we found that NRF2 was overexpressed in a KB-derived drug-resistant cancer cell panel. In this panel, KB-7D cells, which show acquired resistance to topoisomerase II (Top II) poisons, exhibited the highest NRF2 activation.
View Article and Find Full Text PDFIn most hermaphroditic fish, the sexual phase of the gonad responds to external stimuli so that only one sex remains functional while the other sex becomes dormant. However, protandrous black porgy are male during their first two reproductive cycles. Estradiol (E2)-induced female growth results in a transient and immature female, and the sexual phase reverts from female to male after E2 is withdrawn.
View Article and Find Full Text PDFWe have designed and synthesized certain novel oxime- and amide-bearing coumarin derivatives as nuclear factor erythroid 2 p45-related factor 2 (Nrf2) activators. The potency of these compounds was measured by antioxidant responsive element (ARE)-driven luciferase activity, level of Nrf2-related cytoprotective genes and proteins, and antioxidant activity. Among them, (Z)-3-(2-(hydroxyimino)-2-phenylethoxy)-2H-chromen-2-one (17a) was the most active, and more potent than the positive t-BHQ in the induction of ARE-driven luciferase activity.
View Article and Find Full Text PDFThe induction of detoxifying enzymes and antioxidant proteins by chemopreventive agents protects cells from oxidizing substances capable of damaging DNA integrity and initiating carcinogenesis. Coniferyl aldehyde, a naturally occurring substance, has been found in many foods and edible plants. We and others previously demonstrated that trans-coniferylaldehyde (t-CA) has potential antimutagenic and antioxidant properties.
View Article and Find Full Text PDFMisfolded proteins of the endoplasmic reticulum (ER) are eliminated by the ER-associated degradation (ERAD) in eukaryotes. In S. cerevisiae, ER-resident lectins mediate substrate recognition through bipartite signals consisting of an unfolded local structure and the adjacent glycan.
View Article and Find Full Text PDFMisfolded proteins of the endoplasmic reticulum (ER) are retrotranslocated to the cytosol and degraded by the proteasome via a process termed ER-associated degradation (ERAD). The precise mechanism of retrotranslocation is unclear. Here, we use several lumenal ERAD substrates targeted for degradation by the ubiquitin ligase HRD1 including SHH (sonic hedgehog) and NHK (null Hong Kong α1-antitrypsin) to study the geometry, organization, and regulation of the HRD1-containing ERAD machinery.
View Article and Find Full Text PDFEndoplasmic reticulum-associated degradation (ERAD) is an important system that eliminates misfolded proteins from the ER. Three derlins have been implicated in this process, but their precise function remains unknown. In this study, we report that although both derlin1 and derlin2 are capable of binding the ERAD-specific ubiquitin ligase HRD1, they associate with the HRD1-containing complex with different affinities.
View Article and Find Full Text PDFA transmembrane domain (TMD) at the N-terminus of a membrane protein is a signal sequence that targets the protein to the endoplasmic reticulum (ER) membrane. Proline is found more frequently in TM helices compared to water-soluble helices. To investigate the effects of proline on protein translocation and integration in mammalian cells, we made proline substitutions throughout the TMD of dipeptidyl peptidase IV, a type II membrane protease with a single TMD at its N-terminus.
View Article and Find Full Text PDFJ Cell Biol
March 2011
The Hedgehog (Hh) signaling pathway has important functions during metazoan development. The Hh ligand is generated from a precursor by self-cleavage, which requires a free cysteine in the C-terminal part of the protein and results in the production of the cholesterol-modified ligand and a C-terminal fragment. In this paper, we demonstrate that these reactions occur in the endoplasmic reticulum (ER).
View Article and Find Full Text PDFFibroblast activation protein (FAP) is a prolyl-cleaving endopeptidase proposed as an anti-cancer drug target. It is necessary to define its cleavage-site specificity to facilitate the identification of its in vivo substrates and to understand its biological functions. We found that the previously identified substrate of FAP, α(2)-anti-plasmin, is not a robust substrate in vitro.
View Article and Find Full Text PDFFibroblast activation protein (FAP) belongs to the prolyl peptidase family. FAP inhibition is expected to become a new antitumor target. Most known FAP inhibitors often resemble the dipeptide cleavage products, with a boroproline at the P1 site; however, these inhibitors also inhibit DPP-IV, DPP-II, DPP8, and DPP9.
View Article and Find Full Text PDFDipeptidyl peptidase IV (DPP-IV) is a drug target in the treatment of human type II diabetes. It is a type II membrane protein with a single transmembrane domain (TMD) anchoring the extracellular catalytic domain to the membrane. DPP-IV is active as a dimer, with two dimer interacting surfaces located extracellularly.
View Article and Find Full Text PDFBioorg Med Chem Lett
June 2010
A series of 2-[3-[2-[(2S)-2-cyano-1-pyrrolidinyl]-2-oxoethylamino]-3-methyl-1-oxobutyl]-based DPP-IV inhibitors with various monocyclic amines were synthesized. The structure-activity relationships (SAR) led to the discovery of potent DPP-IV inhibitors, having IC(50) values of <100 nM with excellent selectivity over the closely related enzymes, DPP-II, DPP8, DPP9 and FAP (IC(50)>20 microM). Of these compounds, the analogues 12a, 12h and 12i exhibited a long-lasting ex vivo DPP-IV inhibition in rats.
View Article and Find Full Text PDFBiochem Pharmacol
July 2009
DPP-IV (EC 3.4.14.
View Article and Find Full Text PDFA series of (2S)-cyanopyrrolidines with glutamic acid derivatives at the P2 site have been prepared and evaluated as inhibitors of dipeptidyl peptidase IV (DPP-IV). The structure-activity relationships (SAR) led to the discovery of potent 3-substituted glutamic acid analogues, providing enhanced chemical stability and excellent selectivity over the closely related enzymes, DPP8, DPP-II and FAP. Compound 13f exhibited the ability to both significantly decrease the glucose excursion and inhibit plasma DPP-IV activity.
View Article and Find Full Text PDFA series of trans-2-aryl-cyclopropylamine derived compounds were synthesized and evaluated their biological activities against DPP-IV. The structure-activity relationships (SAR) led to the discovery of novel series of DPP-IV inhibitors, having IC(50) values of <100 nM with excellent selectivity over the closely related enzymes, DPP8, DPP-II and FAP. The studies identified a potent and selective DPP-IV inhibitor 24b, which exhibited the ability to both significantly inhibit plasma DPP-IV activity in rats and improve glucose tolerance in lean mice and diet induced obese mice.
View Article and Find Full Text PDFWe have previously shown that six propolins, A-F, could be isolated from Taiwanese propolis (TP) and that they exerted a broad spectrum of biological activities. Recently, we isolated a seventh compound, propolin G. Its chemical structure has been identified by NMR and fast atom bombardment-mass spectrometry spectra and was found to be identical to a known compound, nymphaeol C.
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