Time-dependent Inhibition Research Articles

A New Modeling Approach for Predicting the Growth of Filamentous Algae in Outdoor Algae-Based Wastewater Treatment Systems.

Filamentous algae (FA) can form readily harvestable floating mats or attached turfs that facilitate their application in wastewater treatment systems. However, large-scale implementation is hindered by our inability to predict performance as a function of key operational parameters. A predictive mathematical model would be a valuable tool for designing efficient FA-based systems. Developing accurate models is challenging due to dynamic environmental conditions and the spatial complexities of FA cultures. In this work, a model was developed to mathematically describe the biomass productivity of static FA cultures (mats and turfs) in relation to the incident light intensity and temperature. The model was validated against published data to investigate the influence of time-dependent inhibition (inhibition from sustained light exposure) on productivity. When time-dependent inhibition was included in the model, predictions were within ~10% of experimental values, however, without including time-dependent inhibition there was a sixfold overestimation of biomass productivity. The model could also generate predictions of the effects of time-dependent inhibition during diurnal light fluctuations using experimentally determined rate constants. The model represents a powerful tool for optimizing the design and operational parameters in FA cultures that could be further expanded to incorporate the influence of nutrient and CO2 availability.

Bisubstrate Analog Inhibitors of DXP Synthase Show Species Specificity.

1-Deoxy-d-xylulose 5-phosphate synthase (DXPS) is a unique thiamin diphosphate (ThDP)-dependent enzyme that catalyzes the formation of DXP, a branchpoint metabolite required for the biosynthesis of vitamins and isoprenoids in bacterial pathogens. DXPS has relaxed substrate specificity and utilizes a gated mechanism, equipping DXPS to sense and respond to diverse substrates. We speculate that pathogens utilize this distinct gated mechanism in different ways to support metabolic adaptation during infection. DXPS is susceptible to time-dependent inhibition by bisubstrate analogs. We suggest that potential differences in the ligand-gated mechanism that may accompany alternative activities of DXPS homologues may enable the development of species-specific bisubstrate analog inhibitors. Here, we evaluate known bisubstrate analog inhibitors of Escherichia coli DXPS (EcDXPS) against DXPS from Pseudomonas aeruginosa (PaDXPS), a Gram-negative pathogen with a remarkable capacity to adapt to diverse environments. Our results indicate that these inhibitors are significantly less potent against PaDXPS compared to EcDXPS. Acceptor site residues that stabilize the phosphonolactyl-ThDP adduct (PLThDP) of bisubstrate analog d-PheTrAP on EcDXPS are not as critical for stabilization of this PLThDP adduct on PaDXPS. Substitution of EcR99 or the analogous PaR106 reduces the potency of both d-PheTrAP and the simpler BAP scaffold, suggesting a common role of these arginine residues in stabilizing PLThDP adducts. However, although EcR99 is required for potent, time-dependent inhibition of EcDXPS by d-PheTrAP, PaR106 does not appear to govern slow-onset inhibition. This work demonstrates that species-specific targeting of DXPS by bisubstrate analogs is possible and highlights mechanistic differences that should be considered in the design of homologue-specific inhibitors, toward narrow-spectrum approaches targeting DXPS.

Uncovering the naturally occurring covalent inhibitors of SARS-CoV-2 Mpro from the Chinese medicine sappanwood and deciphering their synergistic anti-Mpro effects.

The Chinese medicine sappanwood is primarily sourced from the dried heartwood of the medicinal plant Caesalpinia sappan Linn., which has been found with a variety of valuable properties including anti-inflammatory, anti-oxidant, and anti-viral effects. Preliminary investigations have demonstrated that sappanwood showed strong anti-SARS-CoV-2 Mpro effects, but the key constituents responsible for SARS-CoV-2 Mpro inhibition and their anti-Mpro mechanisms have not been uncovered. This study aims to uncover the naturally occurring covalent inhibitors of SARS-CoV-2 Mpro from the sappanwood extract (SWE), to characterize the anti-Mpro mechanisms of the newly identified inhibitors in SWE, as well as to elucidate their synergistic anti-Mpro mechanisms. The proteolytic activity of SARS-CoV-2 Mpro was monitored using a fluorescence-based biochemical assay. Comprehensive phytochemical profiling of SWE was conducted by UHPLC-Q-Exactive Orbitrap HRMS. The nanoLC-MS/MS-based chemoproteomic profiling was employed to characterize the phytochemical-modified peptides of SARS-CoV-2 Mpro. Inactivation kinetics, surface plasmon resonance, and molecular dynamics (MD) simulations were utilized to investigate the binding affinity and binding modes of the newly identified SARS-CoV-2 Mpro inhibitors. SWE was found with strong anti-Mpro effect in both dose- and time-dependent manners. Twenty-three constituents in SWE were subsequently identified by utilizing UHPLC-Q-Exactive Orbitrap HRMS, while chemoproteomic profiling revealed that 14 constituents in SWE could covalently modify SARS-CoV-2 Mpro. The anti-SARS-CoV-2 Mpro effects of these newly identified Mpro binders were then tested one by one. The results showed that most of the tested phytochemicals in SWE exhibited time-dependent inhibition on SARS-CoV-2 Mpro, while hematoxylin, brazilin, sappanchalcone, and protosappanin B were identified as the potent time-dependent inhibitors against SARS-CoV-2 Mpro. Furthermore, the combination of hematoxylin and protosappanin B could synergistically block the formation of catalytic active Mpro dimers and then significantly inhibit the catalytic activity of Mpro. MD simulations provided further insight into the synergistic effects between two identified natural Mpro inhibitors (hematoxylin and protosappanin B). The naturally occurring covalent inhibitors of SARS-CoV-2 Mpro from the SWE were identified using an integrated approach. Among all identified covalent inhibitors of SARS-CoV-2 Mpro, hematoxylin, brazilin, sappanchalcone, and protosappanin B emerged as the efficacious Mpro inactivators, which offers powerful evidence to support the anti-coronavirus effects of the Chinese medicine sappanwood.

In vitro assessment of Bionectria ochroleuca metabolites: A promising approach for controlling root-knot nematode, Meloidogyne incognita

Meloidogyne incognita, a highly destructive root-knot nematode, causes substantial crop losses worldwide by infesting plant roots, which disrupts nutrient and water uptake. This pest is notoriously challenging to manage due to its broad host range and growing resistance to many chemical nematicides, emphasizing the urgent need for sustainable, eco-friendly alternatives. In this context, the current study investigated the nematicidal potential of secondary metabolites derived from the entomopathogenic fungus, Bionectria ochroleuca against M. incognita. The in vitro assays demonstrated a dose- and time-dependent inhibition of egg hatching and juvenile survival. At a crude metabolite concentration of 100%, egg hatching was reduced to 5.64% and juvenile mortality increased to 95.4% after 72 h. Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified key metabolites, including palmitic acid, butanedioic acid, lactic acid, and oleic acid, which appear to inhibit nematode growth through mechanisms that impair cell membrane integrity, disrupt energy metabolism, and interfere with essential metabolic pathways. Further, metabolite enrichment analysis revealed their involvement in the biosynthetic pathways, such as unsaturated fatty acids, galactose metabolism, and phenylalanine metabolism. Molecular docking studies supported these findings by showing high binding affinities of these metabolites to virulent nematode proteins, including Cytochrome c oxidase subunit 1 and NAD(H) oxidase, suggesting interference with essential biological processes within the nematode. Overall, these findings position the metabolites of B. ochroleuca as promising candidates for managing nematode infestations, offering a potent alternative to chemical nematicides and thereby contributing to sustainable agricultural practices.

Absorption, single-dose and steady-state metabolism, excretion, and pharmacokinetics of adagrasib, a KRASG12C inhibitor.

This study investigated absorption, metabolism, and excretion of adagrasib after a single oral 600mg dose (1µCi [14C]-adagrasib) in 7 healthy subjects and compared the metabolite profile to the profile at steady-state in 4 patients dosed at 600mg twice daily. Plasma, urine, and feces were collected post [14C]-adagrasib administration and total radioactivity and pooled sample metabolite profiles were determined. Adagrasib pharmacokinetics were determined in plasma and urine. The steady-state plasma metabolite profile was examined in patients and in vitro studies were performed to understand adagrasib's potential to inhibit CYP enzymes and identify CYPs involved in its metabolism. The total mean recovery of the administered radioactivity was 79.2%, with 74.7% and 4.49% of total radioactivity recovered from feces and urine, respectively. Only 1.8% of the dose was excreted in urine as unchanged adagrasib, indicating negligible renal clearance. Adagrasib, M55a, M11, and M68 were major plasma components accounting for 38.3%, 13.6%, 13.4%, and 11.0% of the total plasma radioactivity exposure, respectively. Metabolite M55a was not detected in plasma at steady state where only M68 (24%) and M11 (17.1%) were abundant. In vitro data showed that CYP3A4 (72%) and CYP2C8 (28%) are main contributors to metabolism and adagrasib is a time-dependent inhibitor of CYP3A4. Elimination of adagrasib is mainly by fecal excretion. Adagrasibs altered metabolite profile at steady state is likely due to CYP3A4 autoinhibition. The abundant steady-state plasma metabolites, M68 and M11, are not human specific and do not contribute significantly to the pharmacological activity of adagrasib.

In Silico Enabled Discovery of KAI-11101, a Preclinical DLK Inhibitor for the Treatment of Neurodegenerative Disease and Neuronal Injury.

Dual leucine zipper kinase (DLK), expressed primarily in neuronal cells, is a regulator of neuronal degeneration in response to cellular stress from chronic disease or neuronal injury. This makes it an attractive target for the treatment of neurodegenerative diseases such as Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis, and neuronal injury, such as chemotherapy-induced peripheral neuropathy. Here, we describe the discovery of a potent, selective, brain-penetrant DLK inhibitor, KAI-11101 (59). Throughout the program's progression, medicinal chemistry challenges such as potency, hERG inhibition, CNS penetration, CYP3A time-dependent inhibition, and kinase selectivity were overcome through the implementation of cutting-edge in silico tools. KAI-11101 displayed an excellent in vitro safety profile and showed neuroprotective properties in an ex vivo axon fragmentation assay as well as dose-dependent activity in a mouse PD model.

Discovery of a Novel Mutant-Selective Epidermal Growth Factor Receptor Inhibitor Using an In Silico Enabled Drug Discovery Platform.

Despite the success of first, second, and third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) for non-small cell lung cancer with classical EGFR mutations (L858R or Exon 19 deletions), disease progression occurs due to the acquisition of T790M and C797S resistance. Herein, we report a physics-based computationally driven lead identification approach that identified structurally unique imidazo[3.2-b]pyrazoles as reversible and wild-type-sparing EGFR TKIs of classical mutations bearing both T790M and C797S. During profiling of imidazo[3.2-b]pyrazoles, we elucidated the bioactivation mechanism causing CYP3A4/5 time-dependent inhibition (TDI) and found key modifications to mitigate the TDI. Compound 31 inhibited EGFR L858R/T790M/C797S in biochemical assays with a Ki = 2.1 nM and EGFR del19/T790M/C797S in a Ba/F3 cellular assay with an IC50 = 56.9 nM. The deuterated analogue of 31 (38) demonstrated dose-dependent tumor growth inhibition in a Ba/F3 EGFR del19/T790M/C797S CDX model by 47% at 50 mg/kg BID and 92% at 100 mg/kg BID.

The study of halogen effect on the reactivity of the serine-targeting covalent warheads.

Halogens favorably contributes to the drug potency and metabolic stability via electrostatic interactions. Herein, the halogen effects on the reactivity of the halogenated 2,2,2-trifluoroacetophenones as serine-targeting covalent warheads were investigated. Our results showed that introducing halogen atoms, especially Cl or Br, into the phenyl scaffold would influence the electron density around the ring, which led to different time-dependent inhibition response to the target serine hydrolase (hCES1A). Co-crystallography analysis not only verified that halogenated molecules preferred to form covalent adducts, but also provided the conformational information for the design of covalent inhibitors targeting to hCES1A protein for the treatment of drug-induced acute enteritis.

The neurotoxic effect of Naja nubiae (Serpentes: Elapidae) venom from Sudan.

Neurotoxicity is a common feature of elapid snake envenomation. There are limited studies on the toxicity of Naja nubiae venom, the Nubian spitting cobra, from north-east Africa. We used the chick biventer cervicis nerve-muscle preparation to demonstrate the neurotoxic effect of N. nubiae venom and to compare it with the potent neurotoxic cobra Naja melanoleuca venom. Venoms were separated by successive reverse-phase high-performance liquid chromatography (RP-HPLC) runs and the molecular mass of the neurotoxins was determined by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Both venoms caused time-dependent inhibition of nerve-mediated twitches with a t90 value of 22.2±1.9min and 12.9±1.2min for N. nubiae and N. melanoleuca venoms, respectively. Prior incubation of some commercial antivenom (EchiTab-Plus-ICP [Costa Rica], CSL, Parkville, Victoria, Australia) and snake venom antisera [India]) did not prevent the neurotoxic effect of N. nubiae venom. The chromatographic separation of N. nubiae and N. melanoleuca venoms followed by MALDI-TOF MS analysis revealed that short-chain α-neurotoxin accounted for 8.4% of N. nubiae and 14.8% of N. melanoleuca whole venoms. N. nubiae venom, which was previously known as cytotoxic venom, exhibits considerable in vitro neurotoxic effects on chick nerve-muscle preparations that may have consequences for antivenom development in north-east Africa.

A sulfonimide derivative of bezafibrate as a dual inhibitor of cyclooxygenase-2 and PPARα.

PPARα and cyclooxygenase (COX)-2 are overexpressed in certain types of cancer. Thus, developing a dual inhibitor that targets both could be more effective as an anticancer agent than single inhibitors. We have previously shown that an analog of the bezafibrate named AA520 is a PPARα antagonist. Herein, we report the identification of AA520 as a potent COX-2 inhibitor using in silico approaches. In addition, we performed a thorough pharmacological characterization of AA520 towards COX-1 and COX-2 in different in vitro models. AA520 was characterized for inhibiting platelet COX-1 and monocyte COX-2 activity in human whole blood (HWB) and for effects on lipidomics of eicosanoids using LC-MS/MS. The kinetics of the interaction of AA520 with COX-2 was assessed in the human colon cancer cell line, HCA-7, expressing only COX-2, by testing the COX-2 activity after extensive washing of the cells. The impact of AA520 on cancer cell viability, metabolic activity, and cytotoxicity was tested using the MTT reagent. In HWB, AA520 inhibited in a concentration-dependent fashion LPS-stimulated leukocyte prostaglandin (PG) E2 generation with an IC50 of 0.10 (95% CI: 0.05-0.263) μM while platelet COX-1 was not affected up to 300μM. AA520 did not affect LPS-induced monocyte COX-2 expression, and other eicosanoids generated by enzymatic and nonenzymatic pathways. AA520 inhibited COX-2-dependent PGE2 generation in the colon cancer cell line HCA7. Comparison of the inhibition of COX-2 and its reversibility by AA520, indomethacin (a time-dependent inhibitor), acetylsalicylic acid (ASA) (an irreversible inhibitor), and ibuprofen (a reversible inhibitor) showed that the compound is acting by forming a tightly bound COX-2 interaction. This was confirmed by docking and molecular dynamics studies. Moreover, AA520 (1μM) significantly reduced MTT in HCA7 cells. We have identified a highly selective COX-2 inhibitor with a unique scaffold. This inhibitor retains PPARα antagonism at the same concentration range. It has the potential to be effective in treating certain types of cancer, such as hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC), where COX-2 and PPARα are overexpressed.

The MAPK/ERK signaling pathway involved in Raddeanin A induces apoptosis via the mitochondrial pathway and G2 phase arrest in multiple myeloma

Multiple myeloma (MM) is a hematological malignancy characterized by the unrestricted proliferation of plasma cells that secrete immunoglobulin in the bone marrow. Extracted primarily from Anemone raddeana regel, Raddeanin A (RA) is a natural triterpenoid saponin compound with anti-inflammatory and anti-tumor activities. However, most research on the anti-tumor effects of RA has concentrated on solid tumors, with little exploration into non-solid tumors like MM. Furthermore, there is a dearth of research investigating the interplay between RA and MM, encompassing their interaction targets and mechanisms. This study aims to delve into the biological activity and molecular mechanism of RA’s anti-MM properties through the lens of network pharmacology and experimental validation. The findings from GO enrichment analysis, KEGG enrichment analysis, and molecular docking prediction suggested a potential correlation between the MAPK signaling pathway, including the MAPK1 gene (also known as ERK2), and the impact of RA on MM. Results from the CCK-8 assay revealed a time-dependent and concentration-dependent inhibition of proliferation in MM cell lines treated with RA. Notably, in the cell lines used for the test, the IC50 values for MM.1 S cells were 1.616 µM at 24 H and 1.058 µM at 48 H, for MM.1R cells were 3.905 µM at 24 H and 2.18 µM at 48 H, while for RPMI 8226 cells, they were 6.091 µM at 24 H and 3.438 µM at 48 H. The PI, Annexin V-FITC/PI, and JC-1 staining showed that RA could arrest the cell cycle in the G2 phase, cause apoptosis, and induce the change of mitochondrial membrane potential (MMP) in MM cells. Treated with RA, the Western blot analysis showed that the expression levels of Bim, Cleaved Caspase 3/9, and Cleaved PARP were increased, and the expression level of Mcl-1 was decreased in MM cells. Concurrently, the phosphorylated protein expression levels of p-ERK1/2, p-MSK1, p-P90RSK, and p-MEK1/2 were diminished following RA treatment. These results suggest that RA has the activity of anti-MM, and the MAPK/ERK signaling pathway is involved in the growth inhibition effect of RA on MM cells via cycle arrest and mitochondrial-pathway-dependent apoptosis.

Design, synthesis, and biological evaluation of novel (E)-2-cyano-3-(4,9-dioxo-4,9-dihydronaphtho[2,3-b]furan-2-yl) derivatives as potent STAT3-targeting anticolorectal cancer agents

Dysregulation of signal transducer and activator of transcription 3 (STAT3) is implicated in the pathogenesis of various cancers, underscoring its potential as a cancer therapeutic target. In this work, we designed and synthesized a novel series of (E)-2-cyano-3-(4,9-dioxo-4,9-dihydronaphtho[2,3-b]furan-2-yl) derivatives and evaluated their anti-proliferative effects on tumour cells. Among these derivatives, NW16 exhibited remarkable antiproliferative activity against HCT116 cells, with an IC50 value of 0.28 μM, and exhibited dose- and time-dependent inhibition of the JAK/STAT3 signalling pathway. In addition, NW16 induced reactive oxygen species (ROS) production, which subsequently suppressed the ROS-dependent PI3K/AKT pathway and enhanced its antitumour efficacy. In vivo studies confirmed significant tumour-suppressive effects upon oral administration of NW16 along with favourable tolerability in a colorectal cancer xenograft model. These results indicate that NW16 could be a promising candidate for developing targeted therapy for colorectal cancer because of its multifaceted mechanism.

Discovery of Chalcone Derivatives as Bifunctional Molecules with Anti-SARS-CoV-2 and Anti-inflammatory Activities.

Danshensu extracted with traditional Chinese medicine Salvia miltiorrhiza has a wide range of bioactivities. Danshensu containing a catechol moiety has a moderate inhibitory effect on SARS-CoV-2 3CLpro (IC50 = 2.2 μM) by a reversible covalent interaction and exhibits good anti-inflammatory activity. To enhance the inhibitory activity, we introduced Michael receptors into the side chain of danshensu as a possible covalent warhead and blocked the covalent binding sites of catechol moiety to yield chalcone derivatives. The resulting chalcone derivatives, A4 and A7, were found to inhibit SARS-CoV-2 3CLpro in vitro with IC50 values of 83.2 and 261.3 nM, respectively. Furthermore, A4 and A7 inhibit viral replication in the SARS-CoV-2 replicon system with EC50 values of 19.9 and 11.7 μM, respectively. Time-dependent inhibition experiment and mass spectrometry show that A4 acted as a noncovalent mixed inhibitor, while A7 likely binds covalently at Cys145. The interaction mechanism between SARS-CoV-2 3CLpro and A4 or A7 was characterized by molecular docking studies. Additionally, both A4 and A7 demonstrated potent anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. These promising results suggest that chalcone derivatives A4 and A7 can serve as bifunctional molecules with both antivirus and anti-inflammatory properties.

Drug-induced cholestasis (DIC) predictions based on in vitro inhibition of major bile acid clearance mechanisms.

Drug-induced cholestasis (DIC) is recognized as a major safety concern in drug development, as it represents one of the three types of drug-induced liver injury (DILI). Cholestasis is characterized by the disruption of bile flow, leading to intrahepatic accumulation of toxic bile acids. Bile acid regulation is a multifarious process, orchestrated by several hepatic mechanisms, namely sinusoidal uptake and efflux, canalicular secretion and intracellular metabolism. In the present study, we developed a prediction model of DIC using in vitro inhibition data for 47 marketed drugs on nine transporters and five enzymes known to regulate bile acid homeostasis. The resulting model was able to distinguish between drugs with or without DILI concern (p-value = 0.039) and demonstrated a satisfactory predictive performance, with the area under the precision-recall curve (PR AUC) measured at 0.91. Furthermore, we simplified the model considering only two processes, namely reversible inhibition of OATP1B1 and time-dependent inhibition of CYP3A4, which provided an enhanced performance (PR AUC = 0.95). Our study supports literature findings suggesting a contribution not only from a single process inhibition, but a rather synergistic effect of the key bile acid clearance processes in the development of cholestasis. The use of a quantitative model in the preclinical investigations of DIC is expected to reduce attrition rate in advanced development programs and guide the discovery and development of safe medicines.

Heterotropic allosteric modulation of CYP3A4 invitro by progesterone: Evidence for improvement in prediction of time-dependent inhibition for macrolides.

Predictions of drug-drug interactions resulting from time-dependent inhibition (TDI) of CYP3A4 have consistently overestimated or mispredicted (ie, false positives) the interaction that is observed invivo. Recent findings demonstrated that the presence of the allosteric modulator progesterone (PGS) in the invitro assay could alter the invitro kinetics of CYP3A4 TDI with inhibitors that interact with the heme moiety, such as metabolic-intermediate complex forming inhibitors. The impact of the presence of 100μM PGS on the TDI of molecules in the class of macrolides typically associated with metabolic-intermediate complex formation was investigated. The presence of PGS resulted in varied responses across the inhibitors tested. The TDI signal was eliminated for 5 inhibitors, and unaltered in the case of 1, fidaxomicin. The remaining molecules erythromycin, clarithromycin, and troleandomycin were observed to have a decrease in both potency and maximum inactivation rate ranging from 1.7- to 6.7-fold. These changes in TDI kinetics led to a >90% decrease in inactivation efficiency. To determine invitro conditions that could reproduce invivo inhibition, varied concentrations of PGS were incubated with clarithromycin and erythromycin. The resulting invitro TDI kinetics were incorporated into dynamic physiologically based pharmacokinetic models to predict clinically observed interactions. The results suggested that a concentration of ∼45 μM PGS would result in TDI kinetic values that could reproduce invivo observations and could potentially improve predictions for CYP3A4 TDI. SIGNIFICANCE STATEMENT: The impact of the allosteric heterotropic modulator progesterone on the CYP3A4 time-dependent inhibition kinetics was quantified for a set of metabolic-intermediate complex forming mechanism-based inhibitors. We identify the invitro conditions that optimally predict time-dependent inhibition for invivo drug-drug interactions through dynamic physiologically based pharmacokinetic modeling. The optimized assay conditions improve invitro to invivo translation and prediction of time-dependent inhibition.

Oldenlandia diffusa(Willd.) Roxb. Essential Oil from Assam, India: GC-MS Analysis and Anticancer Activity

In this study essential oil from Oldenlandia diffusa (aerial parts) was extracted using hydrodistillation method. Characterization of the essential oil was done by using GC-MS analysis and identified 71 compounds. Pentacosane (13.29%), hexacosane (11.59%), tetracosane (11.18%), heptacosane (9.76%),tricosane (6.90%), phytol (5.71%), hexatriacontane (4.87%) and isophytol (4.69%) were the major compounds constituting the oil. Further, cytotoxicity of the extracted oil was observed against PA1 (Ovarian), MIAPaCa-2 (Pancreatic), A549 (Lung), MCF7 (Breast), HeLa (Cervical), HepG2 (Liver), PC-3 (Prostatic), MDA-MB-231 (Breast) cell lines. The oil exhibited dose and time dependent inhibition effects against the cancer cell lines. Best inhibition activity was observed against PA1, HeLa and PC-3 cancer cell lines. The IC50 values ranged from 24.19±0.837 - 3.12±0.126 µg/mL in PA1 cells, 51.87±3.104 - 28.95±0.76 µg/mL in HeLa cells and 52.92±1.233 - 14.62±0.465 µg/mL in PC-3 cells at 24, 48 and 72h. From the experiments, it was clear that essential oil of Oldenlandia diffusa should be further explored as an anticancer agent for developing medicinal drug.

Analysis of a high-dimensional free boundary problem on tumor growth with time-dependent nutrient supply and inhibitor action

This paper is concerned with a free boundary problem modeling tumor growth with time-dependent nutrient supply and inhibitor action. We highlight in this paper that the spatial domain occupied by the tumor is set to be n-dimensional for any n⩾3, and it is taken into account that the nutrient supply ϕ(t) and the inhibitor injection ψ(t) on the tumor surface are time-varying in this problem. The high-dimensional setting of the problem makes the proof of the existence of radial stationary solutions and the accurate determination of their numbers highly nontrivial, in which we have developed a new method that is different from the previous work by Cui and Friedman [11]. We can give a complete classification of the radial stationary solutions to this problem under different parameter conditions, and also explore the asymptotic behavior of the transient solution for small c:=c1+c2 in the case that ϕ(t) and ψ(t) have finite limits as t→∞.

Detection and Quantification of Drug-Protein Adducts in Human Liver.

Covalent protein adducts formed by drugs or their reactive metabolites are risk factors for adverse reactions, and inactivation of cytochrome P450 (CYP) enzymes. Characterization of drug-protein adducts is limited due to lack of methods identifying and quantifying covalent adducts in complex matrices. This study presents a workflow that combines data-dependent and data-independent acquisition (DDA and DIA) based liquid chromatography with tandem mass spectrometry (LC-MS/MS) to detect very low abundance adducts resulting from CYP mediated drug metabolism in human liver microsomes (HLMs). HLMs were incubated with raloxifene as a model compound and adducts were detected in 78 proteins, including CYP3A and CYP2C family enzymes. Experiments with recombinant CYP3A and CYP2C enzymes confirmed adduct formation in all CYPs tested, including CYPs not subject to time-dependent inhibition by raloxifene. These data suggest adducts can be benign. DIA analysis showed variable adduct abundance in many peptides between livers, but no concomitant decrease of unadducted peptides. This study sets a new standard for adduct detection in complex samples, offering insights into the human adductome resulting from reactive metabolite exposure. The methodology presented will aid mechanistic studies to identify, quantify and differentiate between adducts that result in adverse drug reactions and those that are benign.

Small Molecule Induces Time-Dependent Inhibition of Stat3 Dimerization and DNA-Binding Activity and Regresses Human Breast Tumor Xenografts.

Aberrantly-active signal transducer and activator of transcription (Stat)3 has a causal role in many human cancers and represents a validated anticancer drug target, though it has posed significant challenge to drug development. A new small molecule, JKB887, was identified through library screening and is predicted to interact with Lys591, Arg609 and Pro63 in the phospho-tyrosine (pTyr)-binding pocket of the Stat3 SH2 domain. JKB887 inhibited Stat3 DNA-binding activity in vitro in a time-dependent manner, with IC50 of 2.2-4.5 μM at 30-60-min incubation. It directly disrupted both the Stat3 binding to the cognate, high-affinity pTyr (pY) peptide, GpYLPQTV-NH2 in fluorescent polarization assay with IC50 of 3.5-5.5 μM at 60-90-min incubation, and to the IL-6 receptor/gp130 or Src in treated malignant cells. Treatment with JKB887 selectively blocked constitutive Stat3 phosphorylation, nuclear translocation and transcriptional activity, and Stat3-regulated gene expression, and decreased viable cell numbers, cell growth, colony formation, migration, and survival in human or mouse tumor cells. By contrast, JKB887 had minimal effects on Stat1, pErk1/2MAPK, pShc, pJAK2, or pSrc induction, or on cells that do not harbor aberrantly-active Stat3. Additionally, JKB887 inhibited growth of human breast cancer xenografts in mice. JKB887 is a Stat3-selective inhibitor with demonstrable antitumor effects against Stat3-dependent human cancers.

A Tale of Two Cases: Acquired Hemophilia A and/or Lupus Anticoagulant?

Abstract Distinguishing between acquired hemophilia A (AHA) and lupus anticoagulant (LA) is essential for effective clinical management. This can be challenging due to similarities in laboratory tests and potential interference between their diagnostic tests. Here we present two complex cases. Case 1 is a 69-year-old female with PNH presenting with a subdural hematoma. Prolonged aPTT with no correction on mixing raised clinical suspicion of AHA. Factor VIII activity was low (2%) across three dilutions in the factor assay. A Bethesda assay revealed a low factor VIII inhibitor (1%). LA was negative by DRVVT. Antiphospholipid antibodies (Cardiolipin and Beta-2-Glycoprotein 1) were also negative. Treatment with prednisone and intravenous immunoglobulin was initiated with presumptive diagnosis of AHA. Subsequent samples to check other factor levels uncovered low Factor IX as well. Higher dilutions in factor assays exhibited non-parallelism in Factor IX and VIII, suggesting a non-specific inhibitor. Chromogenic Factor VIII was within the normal range. Another LA test, Staclot-LA was positive. Overall, this case was consistent with LA rather than AHA. The initial ‘positive’ Bethesda assay was attributed to interference by LA. Case 2 is a 20-year-old female with no significant medical history who was admitted elsewhere for a complicated C-section with intraabdominal hemorrhage. She had prolonged aPTT and positive LA by platelet neutralization test there. Upon transfer, the initial assessment confirmed prolonged aPTT and a time-dependent inhibitor pattern in mixing studies. Factor studies revealed significantly diminished factor VIII activity (<1%) using both one-stage clotting and chromogenic assays. A strong factor VIII inhibitor was identified through chromogenic Bethesda assay (126 BU). Non-parallelism was observed in other factors (Factor IX, XI, XII). LA was negative by DRVVT but positive by Staclot-LA. Cardiolipin and beta2-glycoprotein-1 antibodies were negative. The diagnosis of AHA was evident. But is there concurrent LA present? Both Staclot-LA and platelet neutralization tests are PTT-based and susceptible to interference from factor VIII inhibitor. The patient underwent treatment, and factor VIII inhibitor disappeared in 3 months. Staclot-LA also turned negative, suggesting that the initially ‘positive’ LA test was likely a result of interference. In both cases, adopting a holistic approach to differentiate between AHA and LA is beneficial. Relying solely on individual tests may lead to false interpretations, as LA can inhibit FVIII activity assays and produce false positives in the Bethesda assay. It is advisable to include higher dilutions in factor assays and/or chromogenic assays to mitigate interference. The presence of factor VIII inhibitor can also result in false-positive LA results such as Staclot-LA assay. For more reliable results, DRVVT and antibody tests are preferable. If the aPTT-based assay is the sole positive LA test, the presence of LA is suggested when it occurs before and/or after the presence of a factor inhibitor.