Design of innovative and low-cost dopamine-biotin conjugate sensor for the efficient detection of protein and cancer cells.

The rapid, precise identification and quantification of specific biomarkers, toxins, or pathogens is currently a key strategy for achieving more efficient diagnoses. Herein a dopamine-biotin monomer was synthetized and oxidized in the presence of hexamethylenediamine, to obtain adhesive coatings based on polydopamine-biotin (PDA-BT) on different materials to be used in targeted molecular therapy. Insight into the structure of the PDA-BT coating was obtained by solid-state 13C NMR spectroscopy acquired, for the first time, directly onto the coating, deposited on alumina spheres. The receptor binding capacity of the PDA-BT coating toward 4-hydroxyazobenzene-2-carboxylic acid/Avidin complex was verified by means of UV-vis spectroscopy. Different deposition cycles of avidin onto the PDA-BT coating by layer-by-layer assembly showed that the film retains its receptor binding capacity for at least eight consecutive cycles. Finally, the feasibility of PDA-BT coating to recognize cell lines with different grade of overexpression of biotin receptors (BR) was investigated by tumor cell capture experiments by using MCF-7 (BR+) and HL-60 (BR-) cell lines. The results show that the developed system can selectively capture MCF-7 cells indicating that it could represent a first approach for the development of future more sophisticated biosensors easily accessible, low cost and recyclable with the dual and rapid detection of both proteins and cells.

The Interaction of Myeloperoxidase with the Industrial Contaminant 6-PPD: A Potential Pathway for Reactive Metabolites.

6-PPD (N-[1,3-dimethylbutyl]-N'-phenyl-p-phenylenediamine) is an industrial antioxidant reported to be an environmental contaminant. It was found to be highly toxic to coho salmon and potentially other aquatic organisms. The toxicity of 6-PPD in humans, however, remains unknown. The neutrophil enzyme myeloperoxidase (MPO) is known to catalyze xenobiotic metabolism; therefore, its role in 6-PPD cytotoxicity was investigated using the MPO-rich HL-60 cell line. UV-visible spectroscopy and liquid chromatography-mass spectrometry (LC/MS) were performed to investigate the MPO-mediated oxidation of 6-PPD and identify possible metabolites in the absence and presence of glutathione (GSH). 6-PPD's cytotoxicity, effect on mitochondrial membrane potential (MMP), and GSH-depleting ability in HL-60 cells were assessed. Electron paramagnetic resonance (EPR) was used to determine GSH radical formation using DMPO, and mitochondrial-derived superoxide was assessed with the mito-TEMPO-H probe. Evaluation of the 6-PPD-induced cellular injury pathways was performed by preincubating an antioxidant and an MPO inhibitor with HL-60 cells. UV-vis analysis of MPO-catalyzed oxidation of 6-PPD demonstrated changes in the 6-PPD spectrum, whereas the addition of GSH altered the spectrum, indicating possible GSH conjugate formation. LC/MS showed the formation of multiple products, including GSH-6-PPD conjugates and a GSH conjugate to a 4-hydroxydiphenylamine (a known 6-PPD degradant), which could potentially induce cytotoxicity. 6-PPD demonstrated concentration-dependent cytotoxicity, and cellular GSH levels were decreased by 6-PPD. Similarly, the level of MMP decreased, suggesting mitochondrial depolarization. Furthermore, the EPR spin probe for mitochondrial superoxide showed a positive relationship with 6-PPD concentration, and EPR spin-trapping demonstrated 6-PPD concentration-dependent GSH radical signal intensity using MPO/H2O2. The GSH precursor, NAC, demonstrated partial cytoprotection against 6-PPD; however, the MPO inhibitor PF-1355 surprisingly showed no significant cytoprotective effect. Our results suggest that MPO could be a potential catalyst for 6-PPD toxicity in humans. However, MPO inhibition did not significantly affect cellular viability, suggesting an MPO-independent toxicity pathway. These findings warrant a deeper investigation to determine 6-PPD mammalian toxicity pathways.

Potential of NRF2 Inhibitors-Retinoic Acid, K67, and ML-385-In Overcoming Doxorubicin Resistance in Promyelocytic Leukemia Cells.

Drug resistance is one of the major obstacles to the clinical use of doxorubicin, an extensively used chemotherapeutic drug to treat various cancers, including leukemia. Inhibition of the nuclear factor erythroid 2-related factor 2 (NRF2) seems a promising strategy to reverse chemoresistance in cancer cells. NRF2 is a transcription factor that regulates both antioxidant defense and drug detoxification mechanisms. In this study, we investigated the potential of three inhibitors of NRF2-K67, retinoic acid and ML-385-to overcome doxorubicin resistance in promyelocytic leukemia HL-60 cells. For this purpose, low-dose doxorubicin was used to establish doxorubicin-resistant HL-60/DR cells. The expression of NRF2 and its main repressor, Kelch-like ECH-associated protein 1 (KEAP1), at mRNA and protein levels was examined. HL-60/DR cells overexpressed NRF2 at mRNA and protein levels and down-regulated KEAP1 protein compared to drug-sensitive HL-60 cells. The effects of NRF2 inhibitors on doxorubicin-resistant HL-60/DR cell viability, apoptosis, and intracellular reactive oxygen species (ROS) levels were analyzed. We observed that NRF2 inhibitors significantly sensitized doxorubicin-resistant HL-60/DR cells to doxorubicin, which was associated with increased intracellular ROS levels and the expression of CAS-9, suggesting the participation of the mitochondrial-dependent apoptosis pathway. Furthermore, ML-385 inhibitor was used to study the expression of NRF2-KEAP1 pathway genes. NRF2 gene and protein expression remained unchanged; however, we noted the down-regulation of KEAP1 protein upon ML-385 treatment. Additionally, the expression of NRF2-regulated antioxidant and detoxification genes including SOD2, HMOX2, and GSS was maintained upon ML-385 treatment. In conclusion, our results demonstrated that all the studied inhibitors, namely K67, retinoic acid, and ML-385, increased the efficacy of doxorubicin in doxorubicin-resistant HL-60/DR cells, and suggested a potential strategy of combination therapy using NRF2 inhibitors and doxorubicin in overcoming doxorubicin resistance in leukemia.

[Cytotoxicity Studies of 5-Arylaminouracil Derivatives].

We have previously shown that 5-arylaminouracil derivatives can inhibit HIV-1, herpesviruses, mycobacteria, and other pathogens through various mechanisms. The purpose of this study was to evaluate the potential of 5-arylaminouracils and their derivatives against leukemia, neuroblastoma, and glial brain tumors. 5-Aminouracils with various substituents and their 5'-norcabocyclic and ribo derivatives were screened for cytotoxicity against two neuroblastoma cell lines (SH-SY5Y and IMR-32), K-562 lymphoblastic cells, HL-60 promyeoloblastic cells, and low-passage variants of well-differentiated glioblastoma multiforme (GBM5522 and GBM6138). Cytotoxicity assessment by the standard MTT test showed that most of the compounds lack significant toxicity towards the above cells. However, 5-(4-isopropylphenylamine)uracil and 5-(4-tert-butylphenylamine)uracil exhibited a dose-dependent toxic effect towards the GBM6138 cell line with half-maximal inhibitory concentrations (IC50) of 9 and 2.3 µÐœ, respectively. Antitumor activity was for the first time demonstrated for compounds of this type and can serve as a starting point for further research.

Pharmacological inhibition of cathepsin S and of NSPs-AAP-1 (a novel, alternative protease driving the activation of neutrophil serine proteases).

An uncontrolled activity of neutrophil serine proteases (NSPs) contributes to inflammatory diseases. Cathepsin C (CatC) is known to activate NSPs during neutrophilic differentiation and represents a promising pharmacological target in NSP-mediated diseases. In humans, Papillon-Lefèvre syndrome (PLS) patients have mutations in theirCTSC gene, resulting in the complete absence of CatC activity. Despite this, low residual NSP activities are detected in PLS neutrophils (<10% vs healthy individuals), suggesting the involvement of CatC-independent proteolytic pathway(s) in the activation of proNSPs. This prompted us to characterize CatC-independent NSP activation pathways by blocking proCatC maturation. In this study, we show that inhibition of intracellular CatS almost completely blocked CatC maturation in human promyeloid HL-60 cells. Despite this, NSP activation was not significantly reduced, confirming the presence of a CatC-independent activation pathway involving a CatC-like protease that we termed NSPs-AAP-1. Similarly, when human CD34+ progenitor cells were treated with CatS inhibitors during neutrophilic differentiation in vitro, CatC activity was nearly abrogated but ∼30% NSP activities remained, further supporting the existence of NSPs-AAP-1. Our data indicate that NSPs-AAP-1 is a cysteine protease that is inhibited by reversible nitrile compounds designed for CatC inhibition. We further established a proof of concept for the indirect, although incomplete, inhibition of NSPs by pharmacological targeting of CatC maturation using CatS inhibitors. This emphasizes the potential of CatS as a therapeutic target for inflammatory diseases. Thus, preventing proNSP maturation using a CatS inhibitor, alone or in combination with a CatC/NSPs-AAP-1 inhibitor, represents a promising approach to efficiently control the extent of tissue injury in neutrophil-mediated inflammatory diseases.

Bispecific antibody (ABL602 2 + 1) induced bistable acute myeloid leukemia kinetics.

ABL602 2 + 1, a bispecific antibody with two distinct domains binding to CLL-1 on leukemias and CD3 on T cells, exhibits superior T cell activation and tumour lysing activity. Treatment outcomes of bispecific antibody rely on acute myeloid leukemia cell replication and antibody induced tumour lysing, but their quantitative relationship was unknown. Mathematical models are employed to quantitatively investigate HL-60 cell kinetics determined by bispecific antibody and tumour burden. First, we analysed cytotoxicity assay data testing HL-60 cell against bispecific antibody and T cells, and found efficiency of bispecific antibody induced tumour lysing increases but saturates with increase of HL-60 cell, T cell and bispecific antibody concentration. As a result, their interaction leads to bistable HL-60 cell kinetics; namely, at a given bispecific antibody and T cell concentration interval, HL-60 cell kinetics with small tumour burdens are inhibited but refractory to large tumour burdens. T cell concentration is strong negatively correlated with HL-60 cell concentration. With bispecific antibody clearance, observed bistable HL-60 cell kinetics still exists. Our finding explains observed phenomenon that bispecific antibody was less efficacious at high tumour burden even with enough activated cytotoxic CD8 + T cells. Maintaining high antibody concentration and preventing T-cell exhaustion are equivalently important to sustain long-term control.

Parvovirus B19 Infection Is Associated with the Formation of Neutrophil Extracellular Traps and Thrombosis: A Possible Linkage of the VP1 Unique Region.

Neutrophil extracellular traps (NETs) formation, namely NETosis, is implicated in antiphospholipid syndrome (APS)-related thrombosis in various autoimmune disorders such as systemic lupus erythematosus (SLE) and APS. Human parvovirus B19 (B19V) infection is closely associated with SLE and APS and causes various clinical manifestations such as blood disorders, joint pain, fever, pregnancy complications, and thrombosis. Additionally, B19V may trigger the production of autoantibodies, including those against nuclear and phospholipid components. Thus, exploring the connection between B19V, NETosis, and thrombosis is highly relevant. An in vitro NETosis model using differentiated HL-60 neutrophil-like cells (dHL-60) was employed to investigate the effect of B19V-VP1u IgG on NETs formation. A venous stenosis mouse model was used to test how B19V-VP1u IgG-mediated NETs affect thrombosis in vivo. The NETosis was observed in the dHL-60 cells treated with rabbit anti-B19V-VP1u IgG and was inhibited in the presence of either 8-Br-cAMP or CGS216800 but not GSK484. Significantly elevated reactive oxygen species (ROS), myeloperoxidase (MPO), and citrullinated histone (Cit-H3) levels were detected in the dHL60 treated with phorbol myristate acetate (PMA), human aPLs IgG and rabbit anti-B19V-VP1u IgG, respectively. Accordingly, a significantly larger thrombus was observed in a venous stenosis-induced thrombosis mouse model treated with PMA, human aPLs IgG, rabbit anti-B19V-VP1u IgG, and human anti-B19V-VP1u IgG, respectively, along with significantly increased amounts of Cit-H3-, MPO- and CRAMP-positive infiltrated neutrophils in the thrombin sections. This research highlights that anti-B19V-VP1u antibodies may enhance the formation of NETosis and thrombosis and implies that managing and treating B19V infection could lower the risk of thrombosis.

4-Methylthiazole triggers apoptosis and mitochondrial disruption in HL-60 cells.

BACKGROUND: Thiazole derivatives are gaining prominence in cancer research due to their potent anti-cancer effects and multifaceted biological activities. In leukemia research, these compounds are particularly studied for their ability to induce apoptosis, disrupt mitochondrial membrane potential (MMP), and modulate cell signaling pathways. METHODS AND RESULTS: This study investigates the efficacy of 4-Methylthiazole in inducing apoptosis in HL-60 leukemia cells. Apoptosis was quantified via flow cytometry using FITC Annexin V and propidium iodide staining. Mitochondrial disruption was evaluated through alterations in mitochondrial membrane potential (MMP) as measured by the JC-1 assay. The compound significantly disrupted MMP, activated Caspase-3, and induced the release of Cytochrome C, all of which are critical markers of apoptosis (****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05). Additionally, treatment with 4-Methylthiazole markedly reduced CD45 and CD123 surface markers, indicating significant phenotypic alterations in leukemia cells (****p < 0.0001). High-dose treatment with 4-Methylthiazole significantly increased ROS levels, suggesting elevated oxidative stress and the presence of intracellular free radicals, contributing to its cytotoxic effects (*p < 0.05). A significant rise in TNF-α levels was observed post-treatment, indicating a pro-inflammatory response that may further inhibit leukemia cell viability. While IL-6 levels remained unchanged, a dose-dependent decrease in IL-10 levels was noted, suggesting a reduction in immunosuppressive conditions within the tumor microenvironment (*p < 0.05). CONCLUSIONS: Overall, 4-Methylthiazole targets leukemia cells through multiple apoptotic mechanisms and modifies the immune landscape of the tumor microenvironment, enhancing its therapeutic potential. This study highlights the need for further clinical investigation to fully exploit the potential of thiazole derivatives in leukemia treatment.

Structure elucidation, absolute configuration, and biological evaluation of cyclic peroxides from the sponge Plakinastrella sp.

Two cyclic peroxides, plakortides V (1) and W (2) were purified from the organic extract of the sponge Plakinastrella sp. Their planar structures were established based on extensive NMR and MS analysis and the absolute configurations of the three stereogenic centers of the 1,2-dioxane moiety were determined to be 3R,4S,6S by comparative analysis of the 1H NMR spectral data of the R- or S-MTPA Mosher esters. Compounds 1 and 2 exhibited potent cytotoxic activity against LOX IMVI (melanoma), UO-31 (renal), and HL-60 (TB) (leukemia) cell lines in the NCI-60 cytotoxicity assay.

Rationally designed febuxostat-based hydroxamic acid and its pH-Responsive nanoformulation elicits anti-tumor activity.

Attempts to furnish antitumor structural templates that can prevent the occurrence of drug-induced hyperuricemia spurred us to generate xanthine oxidase inhibitor-based hydroxamic acids and anilides. Specifically, the design strategy involved the insertion of febuxostat (xanthine oxidase inhibitor) as a surface recognition part of the HDAC inhibitor pharmacophore model. Investigation outcomes revealed that hydroxamic acid 4 elicited remarkable antileukemic effects mediated via HDAC isoform inhibition. Delightfully, the adduct retained xanthine oxidase inhibitory activity, though xanthine oxidase inhibition was not the underlying mechanism of its cell growth inhibitory effects. Also, compound 4 demonstrated significant in-vivo anti-hyperuricemic (PO-induced hyperuricemia model) and antitumor activity in an HL-60 xenograft mice model. Compound 4 was conjugated with poly (ethylene glycol) poly(aspartic acid) block copolymer to furnish pH-responsive nanoparticles (NPs) in pursuit of circumventing its cytotoxicity towards the normal cell lines. SEM analysis revealed that NPs had uniform size distributions, while TEM analysis ascertained the spherical shape of NPs, indicating their ability to undergo self-assembly. HDAC inhibitor 4 was liberated from the matrix due to the polymeric nanoformulation's pH-responsiveness, and the NPs demonstrated selective cancer cell targeting ability.

Development of mesoporous magnetic nanoparticles supported idarubicin and investigation of apoptotic and cytotoxic effects on cancer cell lines.

BACKGROUND: Many methods are used for cancer treatment, especially chemotherapy. In addition to the their therapeutic effects, chemotherapeutic drugs also have serious disadvantages, such as not being cell and tissue-specific, causing toxicity in many tissues, and developing drug resistance. Many methods, especially nanocarriers, have been designed to overcome these disadvantages. METHODS AND RESULTS: In this study, we synthesized mesoporous silica iron oxide nanoparticles with different pore diameters and loaded idarubicin (6MFe3O4-NH2-IDA and 35MFe3O4-NH2-IDA). The synthesized molecules were characterized using FT-IR, XRD, and SEM methods. The cytotoxic effects of unbound idarubicin and idarubicin-loaded nanoparticles on MCF7 and HL-60 cell lines were examined by MTT test. Additionally, the expression of anti-apoptotic (Survivin and BCL-2) and apoptotic (BAX, PUMA, and NOXA) genes of the nanoparticles were measured by PCR method. As a result of the analyses, it was seen that nanoparticles with the desired properties and sizes were synthesized. In MTT analysis, it was observed that both nanoparticles dramatically decreased the IC50 value in cell lines. However, the 35MFe3O4-NH2-IDA molecule was found to have lower IC50 values. IC50 values ​​for pristine IDA, 6MFe3O4-NH2, and 35MFe3O4-NH2 at 24 h were found to be 3.56, 1.24 and 0.25 µM in the MCF7 cell line and 4.15, 1.16 and 0.34 µM in the HL-60 cell line, respectively. Additionally, apoptotic gene expression increased, and anti-apoptotic gene expression decreased. CONCLUSIONS: Our study demonstrates that the effectiveness of idarubicin can be significantly enhanced by its application with mesoporous nanocarriers. This enhancement is attributed to the controlled release of idarubicin from the nanocarrier, which circumvents drug resistance mechanisms, improves drug solubility, and increases the drug-carrying capacity per unit volume due to the porous structure of the carrier. These findings underscore the potential of the synthesized nanocarrier in cancer treatment and provide a clear direction for future research in this field.

Moojecin: The first disintegrin from Bothrops moojeni venom and its antitumor activity in acute myeloid leukemia.

Disintegrins are a class of peptides found in snake venom that inhibit the activity of integrins, which are essential cell adhesion receptors in tumor progression and development. In this work, moojecin, a RGD disintegrin, was isolated from Bothrops moojeni snake venom, and its antitumor potential in acute myeloid leukemia (AML) HL-60 and THP-1 cells was characterized. The isolation was performed using a C18 reverse-phase column in two chromatographic steps, and its molecular mass is 7417.84 Da. N-terminal and de novo sequencing was performed to identify moojecin. Moojecin did not show cytotoxic or antiproliferative activity in THP-1 and HL-60 at tested concentrations, but it exhibited significant antimigratory activity in both cell lines, as well as inhibition of angiogenesis in the tube formation assay on Matrigel in a dose-dependent manner. A stronger interaction with integrin αVß3 was shown in integrin interaction assays compared to α5ß1, and the platelet aggregation assay indicated an IC50 of 5.039 µg/mL. Preliminary evaluation of disintegrin toxicity revealed no incidence of hemolysis or cytotoxic effects on peripheral blood mononuclear cells (PBMCs) across the tested concentrations. Thus, this is the first study to report the isolation, functional and structural characterization of a disintegrin from B. moojeni venom and bring a new perspective to assist in AML treatment.

Peptidyl arginine deiminase-4 inhibitor ameliorates pulmonary fibrosis through positive regulation of developmental endothelial locus-1.

Recurring lung injury, chronic inflammation, aberrant tissue repair and impaired tissue remodelling contribute to the pathogenesis of pulmonary fibrosis (PF). Neutrophil extracellular traps (NETs) are released by activated neutrophils to trap, immobilise and kill invading pathogen and is facilitated by peptidyl arginine deiminase-4 (PAD-4). Dysregulated NETs release and abnormal PAD-4 activation plays a crucial role in activating pro-fibrotic events in PF. Developmental endothelial locus-1 (Del-1), expressed by the endothelial cells of lungs and brain acts as an endogenous inhibitor of inflammation and fibrosis. We have hypothesised that PAD-4 inhibitor exerts anti-inflammatory and anti-fibrotic effects in mice model of PF. We have also hypothesised by PAD-4 regulated the transcription of Del-1 through co-repression and its inhibition potentiates anti-fibrotic effects of Del-1. In our study, the PAD-4 inhibitor chloro-amidine (CLA) demonstrated anti-NETotic and anti-inflammatory effects in vitro in differentiated HL-60 cells. In a bleomycin-induced PF mice model, CLA administration in two doses (3 mg/kg, I.P and 10 mg/kg, I.P) improved lung function, normalized bronchoalveolar lavage fluid parameters, and attenuated fibrotic events, including markers of extracellular matrix and epithelial-mesenchymal transition. Histological analyses confirmed the restoration of lung architecture and collagen deposition with CLA treatment. ELISA, IHC, IF, RT-PCR, and immunoblot analysis supported the anti-NETotic effects of CLA. Furthermore, BLM-induced PF reduced Del-1 and p53 expression, which was normalized by CLA treatment. These findings suggest that inhibition of PAD-4 results in amelioration of PF in animal model and may involve modulation of Del-1 and p53 pathways, warranting further investigation.

Metabolic features of neutrophilic differentiation of HL-60 cells in hyperglycemic environments.

INTRODUCTION: Chronic hyperglycemia affects neutrophil functions, leading to reduced pathogen killing and increased morbidity. This impairment has been directly linked to increased glycemia, however, how this specifically affects neutrophils metabolism and their differentiation in the bone marrow is unclear and difficult to study. RESEARCH DESIGN AND METHODS: We used high-resolution respirometry to investigate the metabolism of resting and activated donor neutrophils, and flow cytometry to measure surface CD15 and CD11b expression. We then used HL-60 cells differentiated towards neutrophil-like cells in standard media and investigated the effect of doubling glucose concentration on differentiation metabolism. We measured the oxygen consumption rate (OCR), and the enzymatic activity of carnitine palmitoyl transferase 1 (CPT1) and citrate synthase during neutrophil-like differentiation. We compared the surface phenotype, functions, and OCR of neutrophil-like cells differentiated under both glucose concentrations. RESULTS: Donor neutrophils showed significant instability of CD11b and OCR after phorbol 12-myristate 13-acetate stimulation at 3 hours post-enrichment. During HL-60 neutrophil-like cell differentiation, there was a significant increase in surface CD15 and CD11b expression together with the loss of mitochondrial mass. Differentiated neutrophil-like cells also exhibited higher CD11b expression and were significantly more phagocytic. In higher glucose media, we measured a decrease in citrate synthase and CPT1 activities during neutrophil-like differentiation. CONCLUSIONS: HL-60 neutrophil-like differentiation recapitulated known molecular and metabolic features of human neutrophil differentiation. Increased glucose concentrations correlated with features described in hyperglycemic donor neutrophils including increased CD11b and phagocytosis. We used this model to describe metabolic features of neutrophil-like cell differentiation in hyperglycemia and show for the first time the downregulation of CPT1 and citrate synthase activity, independently of mitochondrial mass.

A novel bioprinted microtumour model for studying acute-leukemia-cell- contaminated in ovarian tissue.

Microtumor models, combining cancer and stromal cells within 3D hydrogels, are vital for testing anticancer therapies. Bioprinting hydrogel scaffolds allows tailored in vitro models. We created a 3D microtumor model using a bioprinter, with varying ratios of ovarian stromal cells and leukemia cells (HL-60). PEGylated fibrinogen and alginate hydrogel were used. Cell dynamics and proliferation were assessed via immunofluorescence staining. Microtumors with different HL-60 ratios (1:1, 1:10, 1:100) were cultured for 5 days. Results showed tumor development modulation by cell ratios and culture time. A significant cell density increase occurred in 1:1 ratio microtumors, indicating rapid cancer cell proliferation. No HL-60 cells were found in 1:100 ratio microtumors by day 5. The 1:10 ratio closely mimicked leukemia invasion in ovarian tissue, showing detectable cancer cells by days 3 and 5 without altering total cell density dynamics significantly. This bioprinted leukemia microtumor model offers better physiological relevance than 2D assays, promising applications in cellular analysis and drug screening.

Discovery of Novel Mcl-1 Inhibitors with a 3-Substituted-1H-indole-1-yl Moiety Binding to the P1-P3 Pockets to Induce Apoptosis in Acute Myeloid Leukemia Cells.

Mcl-1 is a main antiapoptotic protein in acute myeloid leukemia (AML) and is used as a target to develop inhibitors. Currently, potent Mcl-1 inhibitors primarily interact with the P2-P4 pockets of Mcl-1, but pharmacological modulation by targeting the P1 pocket is less explored. We designed a series of 1H-indole-2-carboxylic acid compounds as novel Mcl-1 inhibitors occupying the P1-P3 pockets and evaluated their Mcl-1 inhibition and apoptosis induction in AML cells. Two-dimensional 15N-HSQC spectroscopy indicated that 47 (Ki = 24 nM) bound to the BH3 binding groove, occupied the P1 pocket in Mcl-1, and formed interactions with Lys234 and Val249. 47 exhibited good microsomal stability and pharmacokinetic profiles, with low potential risk of cardiotoxicity. 47 inhibited tumor growth in HL-60 and THP-1 xenograft models with growth inhibition rate of 63.7% and 57.4%, respectively. Collectively, 47 represents a novel Mcl-1 inhibitor targeting the P1-P3 pockets with excellent antileukemia effects.

The role of PI3K-Akt-mTOR axis in Warburg effect and its modification by specific protein kinase inhibitors in human and rat inflammatory macrophages.

The Warburg effect occurs both in cancer cells and in inflammatory macrophages. The aim of our work was to demonstrate the role of PI3K-Akt-mTOR axis in the Warburg effect in HL-60 derived, rat peritoneal and human blood macrophages and to investigate the potential of selected inhibitors of this pathway to antagonize it. M1 polarization in HL-60-derived and human blood monocyte-derived macrophages was supported by the increased expression of NOS2 and inflammatory cytokines. All M1 polarized and inflammatory macrophages investigated expressed higher levels of HIF-1α and NOS2, which were reduced by selected kinase inhibitors, supporting the role of PI3K-Akt-mTOR axis. Using Seahorse XF plates, we found that in HL-60-derived and human blood-derived macrophages, glucose loading reduced oxygen consumption (OCR) and increased glycolysis (ECAR) in M1 polarization, which was antagonized by selected kinase inhibitors and by dichloroacetate. In rat peritoneal macrophages, the changes in oxidative and glycolytic metabolism were less marked and the NOS2 inhibitor decreased OCR and increased ECAR. Non-mitochondrial oxygen consumption and ROS production were likely due to NADPH oxidase, expressed in each macrophage type, independently of PI3K-Akt-mTOR axis. Our results suggest that inflammation changed the metabolism in each macrophage model, but a clear relationship between polarization and Warburg effect was confirmed only after glucose loading in HL-60 and human blood derived macrophages. The effect of kinase inhibitors on Warburg effect was variable in different cell types, whereas dichloroacetate caused a shift toward oxidative metabolism. Our findings suggest that these originally anti-cancer inhibitors may also be candidates for anti-inflammatory therapy.

Luteolin Inhibits Indoxyl Sulfate-Induced ICAM-1 and MCP-1 Expression by Inducing HO-1 Expression in EA.hy926 Human Endothelial Cells.

In patients with chronic kidney disease, the uremic toxin indoxyl sulfate (IS) accelerates kidney damage and the progression of cardiovascular disease. IS may contribute to vascular diseases by inducing inflammation in endothelial cells. Luteolin has documented antioxidant and anti-inflammatory properties. This study aimed to investigate the effect of luteolin on IS-mediated reactive oxygen species (ROS) production and intercellular adhesion molecule (ICAM-1) and monocyte chemoattractant protein (MCP-1) expression in EA.hy926 cells and the possible mechanisms involved. IS significantly induced ROS production (by 6.03-fold, p < 0.05), ICAM-1 (by 2.19-fold, p < 0.05) and MCP-1 protein expression (by 2.18-fold, p < 0.05), and HL-60 cell adhesion (by 31%, p < 0.05), whereas, luteolin significantly decreased IS-induced ROS production, ICAM-1 and MCP-1 protein expression, and HL-60 cell adhesion. Moreover, luteolin attenuated IS-induced nuclear accumulation of p65 and c-jun. Luteolin dose-dependently increased heme oxygenase-1 (HO-1) expression and the maximum fold induction of HO-1 by luteolin was 3.68-fold (p < 0.05), whereas, HO-1 knockdown abolished the suppression of ICAM-1 and MCP-1 expression by luteolin. Luteolin may protect against IS-induced vessel damage by inducing HO-1 expression in vascular endothelial cells, which suppresses nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1) mediated ICAM-1 and MCP-1 expression.

Sodium Acetate Enhances Neutrophil Extracellular Trap Formation via Histone Acetylation Pathway in Neutrophil-like HL-60 Cells.

Neutrophil extracellular trap formation has been identified as a new cell death mediator, termed NETosis, which is distinct from apoptosis and necrosis. NETs capture foreign substances, such as bacteria, by releasing DNA into the extracellular environment, and have been associated with inflammatory diseases and altered immune responses. Short-chain fatty acids, such as acetate, are produced by the gut microbiota and reportedly enhance innate immune responses; however, the underlying molecular mechanisms remain unclear. Here, we investigated the effects of sodium acetate, which has the highest SCFA concentration in the blood and gastrointestinal tract, on NETosis by focusing on the mechanisms associated with histone acetylation in neutrophil-like HL-60 cells. Sodium acetate enhanced NETosis, as shown by fluorescence staining with SYTOX green, and the effect was directly proportional to the treatment duration (16-24 h). Moreover, the addition of sodium acetate significantly enhanced the acetylation of Ace-H3, H3K9ace, and H3K14ace. Sodium acetate-induced histone acetylation rapidly decreased upon stimulation with the calcium ionophore A23187, whereas histone citrullination markedly increased. These results demonstrate that sodium acetate induces NETosis via histone acetylation in neutrophil-like HL-60 cells, providing new insights into the therapeutic effects based on the innate immunity-enhancing effect of dietary fiber.

Exploring the effects of three-finger toxins from Naja ashei venom on neuronal and immunological cancer cell membranes.

Three-finger proteins are the most abundant toxins in the venom of Naja ashei, a snake species from the Elapidae family. This research aimed to describe the effects of varying charges of these proteins, isolated from Naja ashei venom using SEC and IEX chromatography. The study examined how differently charged three-finger toxin fractions interact with and affect neuroblastoma (SK-N-SH) and promyeloblast (HL-60) cells, as well as model Langmuir membranes and liposomes designed to mimic cellular lipid composition. Findings revealed that protein surface charges significantly impact cell survival (MTT assay), membrane damage (lactate dehydrogenase release, malondialdehyde formation), and the structural and electrochemical properties of model membranes (Langmuir membranes and zeta potential for liposomes and cancer cell lines). Results indicated that SK-N-SH cells, characterized by a higher negative charge on their cell membranes, interacted more effectively with positively charged toxins than HL-60 cells. However, the mechanism of these electrostatic interactions is complex. The research demonstrated that electrostatic and mechanical membrane modifications induced by venom proteins can significantly affect cell metabolism. Additionally, the total charge of the membrane, influenced by polar lipid components and phospholipid saturation, plays a decisive role in toxin interaction.