Human Leukemia Cells Research Articles

Pyroptosis is not likely to play a major role in anthracycline-induced cytotoxicity in H9c2 cardiomyocytes and human cardiac endothelial cells

Abstract Background Although anthracyclines are widely used as effective chemotherapeutic agents, anthracycline-induced cardiotoxicity (AIC) causes significant morbidity and mortality. The precise mechanism of AIC remains elusive, although apoptosis may be involved. Recent research suggests pyroptosis, a programmed lytic cell death pathway, might also contribute to AIC. Although studies have focused on AIC in the myocardium, emerging evidence suggests that AIC may also affect vascular cells. Furthermore, the cytotoxicity of doxorubicin (DOX) or its supposed active metabolite, doxorubicinol (DOXOL), has not been widely investigated in cardiac vascular cells. Purpose This study examines the hypothesis that pyroptosis plays a role in DOX and DOXOL cytotoxicity in H9c2 immortalised rat cardiac myoblasts and two types of human cardiac endothelial cells. Methods In vitro experiments were conducted to ascertain dose-dependent toxicity in H9c2, and cardiac endothelial cells following treatment with DOX or DOXOL. The type of cell death was determined by assessing cell morphology and fluorescent staining with markers of apoptosis (Annexin V) and lytic cell death (Propidium Iodide PI) following DOX or DOXOL treatment in comparison to known inducers of pyroptosis (LPS & Nigericin). Western blot experiments were conducted to study the expression of GSDMD (involved in pyroptosis), and caspase 3 (involved in apoptosis), following DOX or DOXOL. A human monocytic acute myeloid leukaemia cell line (THP-1 cells) was used as a positive control for pyroptosis. Results Dose-dependent cell death following DOX treatment was higher than with DOXOL in both H9c2 and cardiac endothelial cells. DOX caused apoptotic changes in all cell types. In contrast, DOXOL had weaker effects, inducing early apoptosis. No cleavage (activation) of GSDMD or caspase 3 was detected after DOX or DOXOL. Interestingly, in THP-1 cells, DOX induced predominantly apoptotic cell death, whereas DOXOL induced predominantly pyroptotic cell death, assessed both morphologically and by caspase 3 and GSDMD cleavage. Conclusion DOX and DOXOL primarily induce apoptotic cell death in H9c2 cardiomyocytes and cardiac endothelial cells. Interestingly, DOXOL, supposedly the active metabolite, was less cytotoxic than DOX. THP-1 cells undergo apoptotic or pyroptotic cell death with DOX or DOXOL, respectively. In conclusion, anthracycline-induced cytotoxicity is likely to be due to apoptotic injury rather than pyroptosis.

Anti-IL-1RAP scFv-mSA-S19-TAT fusion carrier as a multifunctional platform for versatile delivery of biotinylated payloads to myeloid leukemia cells

Acute myeloid leukemia (AML) is an aggressive blood cancer with frequently poor clinical outcomes. This heterogeneous malignancy encompasses genetically, molecularly, and even clinically different subgroups. This makes it difficult to develop therapeutic agents that are effective for all subtypes of the disease. Therefore, a selective, universal, and adaptable delivery platform capable of carrying various types of anti-neoplastic agents is an unmet requirement in this area. Two multifunctional fusion proteins were designed for the delivery of biotinylated cargoes to human myeloid leukemia cells by fusing an anti-IL-1RAP single-chain antibody with streptavidin (tetramer or monomer), a cell-penetrating peptide (CPP), and an endosomolytic peptide in a single biomacromolecule. The designed fusions were analyzed primarily in silico, and the biofunctionality of the selected fusion was fully characterized via several binding assays, hemolysis assay, confocal microscopy and cell cytotoxicity assay after production via the Escherichia coli (E. coli) system. The refolded protein exhibited desirable binding activity to leukemic cells, pure antigen and biotinylated BSA. Further analyses revealed efficient cellular uptake, endosomolytic activity, and nuclear penetration without any detectable cytotoxicity toward normal epithelial cells. The described platform seems to have great potential for targeted delivery of different therapeutics to malignant myeloid cells.

Investigation of Apoptosis-mediated Cytotoxic Effects of Royal Jelly on HL-60 Cells

In recent years, the use of nontoxic natural products that can be effective on cancer cells as new agents has attracted the attention of scientists in order to reduce the negative side effects of existing cancer drugs and their toxicity to normal cells. Some in vivo and in vitro studies have shown that royal jelly (RJ) inhibits cell proliferation and induces apoptosis. In this research, we aimed to investigate the effects of RJ on proliferative and apoptotic processes in the human acute promyelocytic leukemia cell line (HL-60). The HL60 cell line was treated with different concentrations of RJ for 24, 48, and 72 hours. The half maximum inhibitory concentration (IC50) of RJ was determined using 3-(4.5 dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide test (MTT) and the proliferation activity of HL-60 cells was evaluated. Flow cytometry analysis was performed to measure apoptosis in HL-60 cells. IC50 values for RJ were calculated as 13.98, 6.45, and 2.06 mg/mL for 24, 48, and 72 hours, respectively. Flow cytometry results also showed that RJ had apoptotic effects at the concentrations found. The results showed that RJ treatment significantly induced apoptosis and reduced the proliferation of HL-60 cells. This study shows that RJ can be a complementary treatment against HL-60 acute myeloid leukemia cells due to its anticancer and antiproliferative effects.

Enzymatic reaction and competitive prereduction enable label-free and separation-free inductively coupled plasma mass spectrometry detection of leukemia cells

The enzyme terminal deoxynucleotidyl transferase (TdT) exhibits significant activity in various leukemia cells, including human acute lymphoblastic leukemia cells (CCRF). It demonstrates substantial potential as a diagnostic biomarker for acute lymphoblastic leukemia (ALL). Herein, a highly sensitive method for the homogeneous quantification of TdT and CCRF cells, without the need for labeling or separation, was established based on inductively coupled plasma mass spectrometry (ICP-MS). The simple sensor relied on the TdT-induced polymerization process, lengthening the DNA strand and producing large amounts of the by-product phosphates of pyrophosphate (PPi). The PPi formed complexes with Cu²⁺, altering its morphology in homogeneous systems. The remaining Cu²⁺ competed with Hg²⁺ in consuming ascorbic acid (AA) through the pre-reduction of Hg²⁺, affecting the ICP-MS signal of Hg²⁺. Under optimal conditions, this approach exhibited excellent specificity and ultrahigh sensitivity, with limits of detection (LODs) as low as 0.05 U/L for TdT and 5 cells/mL for CCRF cells, respectively. The proposed method offers significant advantages, including high sensitivity and precision, operation at room temperature without the involvement of proteases, and the ability to accurately quantify in complex biological matrices. Consequently, the proposed method shows great promise as a valuable tool for TdT-related biological research and leukemia diagnosis.

High glucose condition aggravates inflammatory response induced by Porphyromonas gingivalis in THP-1 macrophages via autophagy inhibition

BackgroundPorphyromonase gingivalis (P. gingivalis) is a type of bacteria that causes periodontitis, which is strongly correlated with systemic diseases such as diabetes. However, the effect of hyperglycemia on periodontitis are unclear. The present study examined the effects of high glucose levels on the response to P. gingivalis infection.ResultsThe expression of P. gingivalis-induced interleukin-1β (IL-1β) and inflammasomes increased as the glucose concentration increased. High glucose conditions suppressed P. gingivalis–induced autophagy in human acute monocytic leukemia cell line (THP-1) macrophages. Zingerone increased autophagy and alleviated P. gingivalis-induced inflammatory response in THP-1 macrophages under high glucose conditions. In addition, P. gingivalis- induced inflammation in bone marrow-derived macrophages of diabetic mice was higher than in wild-type mice, but a zingerone treatment decreased the levels. Alveolar bone loss due to a P. gingivalis infection was significantly higher in diabetic mice than in wild-type mice.ConclusionsHigh-glucose conditions aggravated the inflammatory response to P. gingivalis infection by suppressing of autophagy, suggesting that autophagy induction could potentially to treat periodontitis in diabetes. Zingerone has potential use as a treatment for periodontal inflammation induced by P. gingivalis in diabetes patients.

BCAT1 contributes to the development of TKI-resistant CML.

Although most of chronic myeloid leukemia (CML) patients can be effectively treated by the tyrosine kinase inhibitors (TKIs), such as Imatinib, TKI-resistance still occurs in approximately 15-17% of cases. Although many studies indicate that branched chain amino acid (BCAA) metabolism may contribute to the TKI resistance in CML, the detailed mechanisms remains largely unknown. The cell proliferation, colony formation and in vivo transplantation were used to determined the functions of BCAT1 in leukemogenesis. Quantitative real-time PCR (RT-PCR), western blotting, RNA sequencing, BCAA stimulation in vitro were applied to characterize the underlying molecular mechanism that control the leukemogenic activity of BCAT1-knockdown cells. In this report, we revealed that branched chain amino acid transaminase 1 (BCAT1) is highly enriched in both mouse and human TKI-resistant CML cells. Leukemia was almost completely abrogated upon BCAT1 knockdown during transplantation in a BCR-ABLT315I-induced murine TKI-resistant CML model. Moreover, knockdown of BCAT1 led to a dramatic decrease in the proliferation of TKI-resistant human leukemia cell lines. BCAA/BCAT1 signaling enhanced the phosphorylation of CREB, which is required for maintenance of TKI-resistant CML cells. Importantly, blockade of BCAA/BCAT1 signaling efficiently inhibited leukemogenesis both in vivo and in vitro. These findings demonstrate the role of BCAA/BCAT1 signaling in cancer development and suggest that targeting BCAA/BCAT1 signaling is a potential strategy for interfering with TKI-resistant CML.

Clerodane diterpene 3-deoxycaryoptinol (Clerodin) selectively induces apoptosis in human monocytic leukemia (THP-1) cells and upregulates apoptotic protein caspase-3

3-deoxycaryoptinol (Clerodin) is a clerodane diterpene isolated from the leaves of Clerodendrum infortunatum. The present research investigates the anticancer therapeutic efficacy of clerodin in human monocytic leukemic (THP-1) cells for the first time. In vitro assay using THP-1 cells showed the cytotoxic ability of clerodin. Further, Annexin-V(FITC)/PI and intracellular ROS (DCFDA) assays carried out using flow cytometry, and confocal laser scanning microscopy confirmed the apoptotic potential of clerodin. Moreover, the western blot was used to detect mitochondrial apoptosis of THP-1 cells. RT-PCR, ELISA, and western blot analysis clearly indicated that clerodin significantly increased the expression of pro-apoptotic marker caspase-3 in THP-1 cells. clerodin also selectively targeted the G2/M phase of THP-1 cells, a key feature for anticancer molecules. Importantly, the clerodin did not exhibit cytotoxicity against human peripheral blood cells. These properties of clerodin make it a potential chemotherapeutic agent that can selectively induce apoptosis in leukemia-like cancer cells.

Phenolic Bisabolane Sesquiterpene Derivatives from an Arctic Marine-derived Fungus Aspergillus sydowii MNP-2

Background:: Filamentous fungi in the genus Aspergillus are well known for their important roles in production of bioactive secondary metabolites with diversely chemical structures and potential application in pharmaceutical industry. Objective:: The present study aimed to investigate the phenolic bisabolane sesquiterpene (PBS) derivatives from an Arctic marine-derived fungus Aspergillus sydowii MNP-2. Methods:: In this study, antimicrobial activities were carried out according to the broth microdilution assay, nitric oxide (NO) production in mouse macrophages (RAW264.7) and BV2 microglial cells was used to detect the inhibitory effect of compounds in inflammatory reactions, and in vitro inhibitory cell proliferation activity was determined by the cell counting kit-8 (CCK-8) assay. Results:: In this work, chemical investigation of an Arctic marine-derived strain A. sydowii MNP-2 led to the isolation of 11 PBSs (1-11) using various chromatographic methods. Their chemical structures were unambiguously determined by 1H NMR spectroscopy and mass spectrometry analyses as well as comparison with literature data. It is noteworthy that compounds 1, 7 and 11 were firstly obtained from A. sydowii. Antimicrobial assay showed that these chemicals had no potent inhibitory effect on Staphylococcus aureus, Escherichia coli, and Candida albicans with MIC values > 16 μg/mL. Additionally, the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)- induced inflammation in mouse macrophages (RAW264.7) and BV2 microglial cells were all below 10% for compounds 4-6 and 8, indicating almost negligible anti-inflammatory efficacy. Among the tested compounds 4-6 and 8 for tumor-cell proliferation inhibition activities, compound 5 demonstrated the strongest inhibitory effect against human acute promyelocytic leukemia cells (HL-6) with a 44.76% inhibition rate. Conclusion:: In the present study, 11 PBS derivatives were purified and characterized from the solidand liquid-state fermentations of the Arctic marine-derived fungus A. sydowii MNP-2. Unfortunately, none of these metabolites had significant antimicrobial, anti-inflammatory, or tumor-cell proliferation inhibition activities.

Progesterone decreases viability and up regulates membrane progesterone receptors expression on the human Chronic Myeloid Leukemia cell line

Progesterone (P4)) has an important effect (activatory or inhibitory) on cell proliferation. Although there is evidence of the impact of progesterone on sex-linked cancers, it can affect other cancer cells expressing P4 receptors (PRs). We evaluated the expression of membrane P4 receptors (mPRs) and the viability in progesterone-treated K562 cells to inspect the possible effects route of progesterone on this (CML) cancer cell line. K562 cells were exposed to various concentrations of progesterone or no exposure for 48 and 72 hours. The percentage of viability and cells that expressed mPRα and mPRβ were evaluated by MTT test and flow cytometry respectively. Progesterone significantly increased the expression of mPRα and especially mPRβ on the surface of K562 cells and significantly decreased their viability (p ≤ 0.05). Progesterone can reduce viability in K562 cells. Our findings showed that progesterone affects its receptor expression on K562 cells. Thus it may influence the performance of K562 cells in addition to its direct effects on these cells (via binding to its receptors).

The cytotoxic activities of the major diterpene extracted from Salvia multicaulis (Bardakosh) are mediated by the regulation of heat-shock response and fatty acid metabolism pathways in human leukemia cells

BackgroundLeukemia is one of the most lethal cancers worldwide and represents the sixth-leading cause of cancer deaths. The results of leukemia treatment have not been as positive as desired, and recurrence is common. PurposeThus, there is an urgent requirement for the development of new therapeutic drugs. Salvia multicaulis (Bardakosh) is a widespread species that contains multiple phytochemical components with anti-cancer activities. MethodsWe isolated and characterized the major diterpene candesalvone B methyl ester from S. multicaulis and investigated its action as a cytotoxic agent towards sensitive and drug-resistant leukemia cells by the resazurin reduction assay. Additionally, the targeted genes and the affected molecular mechanisms attributed to the potent cytotoxic activities were discovered by transcriptome-wide mRNA expression profiling. The targets predicted to be regulated by candesalvone B methyl ester in each cell line were confirmed by qRT-PCR, molecular docking, microscale thermophoresis, and western blotting. Moreover, cell cycle distribution and apoptosis were analyzed by flow cytometry. ResultsCandesalvone B methyl ester was cytotoxic with IC50 values of 20.95 ± 0.15 µM against CCRF-CEM cells and 4.13 ± 0.10 µM against multidrug-resistant CEM/ADR5000 leukemia cells. The pathway enrichment analysis disclosed that candesalvone B methyl ester could regulate the heat-shock response signaling pathway via targeting heat shock factor 1 (HSF1) in CCRF-CEM cells and ELOVL fatty acid elongase 5 (ELOVL5) controls the fatty acid metabolism pathway in CEM/ADR5000 cells. Microscale thermophoresis showed the binding of candesalvone B methyl ester with HSF1 and ELOVL5, confirming the results of molecular docking analysis. Down-regulation of both HSF1 and ELOVL5 by candesalvone B methyl ester as detected by both western blotting and RT-qPCR was related to the reversal of drug resistance in the leukemia cells. Furthermore, candesalvone B methyl ester increased the arrest in the sub-G1 phase of the cell cycle in a dose-dependent manner from 1.3 % to 32.3 % with concomitant induction of apoptosis up to 29.0 % in CCRF-CEM leukemic cells upon inhibition of HSF1. ConclusionCandesalvone B methyl ester isolated from S. multicaulis exerted cytotoxicity by affecting apoptosis, cell division, and modulation of expression levels of genes contributing to the heat stress signaling and fatty acid metabolism pathways that could relieve drug resistance of leukemia cells.

Inhibition of calpain reduces oxidative stress and attenuates pyroptosis and ferroptosis in Clostridium perfringens Beta-1 toxin-induced macrophages

Clostridium perfringens Beta-1 toxin (CPB1) is a lethal toxin, which can lead to necrotic enteritis, but the pathological mechanism has not been elucidated. We investigated whether reactive oxygen species (ROS) participated in CPB1-induced pyroptosis and ferroptosis, and investigated the effects of calpain on CPB1-induced oxidative stress and inflammation. Scavenging ROS by N-acetyl cysteine (NAC) led to the reduction of ROS, inhibited the death of macrophages, cytoplasmic swelling and membrane rupture, the expression of pyroptosis-related proteins and proinflammatory factor, while increased the expression of anti-inflammatory factors in cells treated with rCPB1. Adenosine triphosphate (ATP) synthase, H+ transporting, mitochondrial F1 complex, alpha subunit 1 (ATP5A1) was identified specifically interact with rCPB1. Silencing ATP5A1 inhibited accumulation of ATP and ROS, leaded to less cytoplasmic swelling and membrane rupture, attenuated pyroptosis and inflammation in rCPB1-treated cells. We also found that rCPB1 induces ferroptosis in macrophages, and the level of ferroptosis was similar with H2O2. Of note, H2O2 is a major ROS source, indicated that ROS production may play a major role in the regulation of ferroptosis in macrophages treated with rCPB1. This finding was further corroborated in rCPB1- induced human acute monocytic leukemia cells, which were treated with NAC. In addition, the inhibition of ferroptosis using liproxstatin-1 inhibited the shriveled mitochondrial morphology, increased the expression of glutathione peroxidase 4, nicotinamide adenine dinucleotide (phosphate) hydrogen: quinone oxidoreductase 1 and cysteine/glutamic acid reverse transport solute carrier family 7 members 11, decreased the expression of heme oxygenase 1, nuclear receptor coactivator 4 and transferrin receptor proteins, reduced malondialdehyde and lipid peroxidation levels, and increased intracellular L-glutathione levels in cells treated with rCPB1. Furthermore, calpain inhibitor PD151746 was used to investigate how pyroptosis and ferroptosis were involved simultaneously in rCPB1-treated macrophages. We showed that PD151746 inhibited ATP and ROS production, reversed the representative pyroptosis/ferroptosis indicators and subsequently reduced inflammation. The above findings indicate that rCPB1 might lead to macrophage pyroptosis and ferroptosis through the large and sustained increase in intracellular calpain and oxidative stress, further lead to inflammation.

Targeting USP14/UCHL5: A Breakthrough Approach to Overcoming Treatment-Resistant FLT3-ITD-Positive AML.

FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) mutations in acute myeloid leukemia (AML) are associated with poor prognosis and therapy resistance. This study aimed to demonstrate that inhibiting the deubiquitinating enzymes ubiquitin-specific peptidase 14 (USP14) and ubiquitin C-terminal hydrolase L5 (UCHL5) (USP14/UCHL5) with b-AP15 or the organogold compound auranofin (AUR) induces apoptosis in the ITD-transformed human leukemia cell line MV4-11 and mononuclear leukocytes derived from patients with FLT3-ITD-positive AML. This study included patients diagnosed with AML at Tokyo Medical and Dental University Hospital between January 2018 and July 2024. Both treatments blocked downstream FLT3 pathway events, with the effects potentiated by USP14 knockdown. Both treatments inhibited FLT3 deubiquitination via K48 and disrupted translation initiation via 4EBP1, a downstream FLT3 target. FLT3 was downregulated in the leukemic cells, with the associated activation of stress-related MAP kinase pathways and increased NF-E2-related factor 2. Furthermore, the overexpression of B-cell lymphoma-extra-large and myeloid cell leukemia-1 prevented the cell death caused by b-AP15 and AUR. These results suggest that inhibiting USP14/UCHL5, which involves multiple regulatory mechanisms, is a promising target for novel therapies for treatment-resistant FLT3-ITD-positive AML.

Marine Bioactives in Cancer Prevention and Treatment

The twice high incidence risk of cancer in men was the reason for over a million new cases and deaths recorded globally in 2018. The two most frequent cancer-related fatalities are lung and breast cancer. Novel therapies have been made possible by developments in immunotherapy, biology, and pharmaceutical design. Novel cancer prevention and therapy elements are being made possible by technological advancements and studies on marine natural resources. The creation of innovative anticancer medications is utilizing marine-derived natural products (MNPs). Biologically active polyketides, high molecular weight organic sugars, terpenes, bioengineered alkaloids, and marine animal peptides are some examples of these MNPs. Anticancer drugs are also developed with the help of plants, animals, invertebrates, and microbes found on land. The National Cancer Institute is exploring the potential of nutrition and food in cancer prevention despite the absence of preclinical and clinical data. Marine organisms contain bioactive compounds that have potential anticancer effects. Polyphenols, polysaccharides, and alkaloids are some of the active components found in marine species. Polyphenols, found in edible seaweeds like Palmaria palmata, can lower cancer cell division and proliferation, while polysaccharides trigger the innate immune system, causing apoptosis in pancreatic islet cancer and human leukemia cells. Alkaloids, derived from marine sources, can inhibit cancer cell development. Peptides, found in various plant species, have shown cytotoxic effects on several human cell lines, including pancreatic, breast, lung, and bladder cancers. Marine drug approval faces challenges like the possibility of a resurgence of different metabolites due to environmental conditions and limited lead compound availability.

Capsular polysaccharide from the marine bacterium Cobetia marina induces apoptosis via both caspase-dependent and mitochondria-mediated pathways in HL-60 cells

In the present study, we investigated the antiproliferative effect of the capsular polysaccharide (CPS) from marine Gram-negative bacterium Cobetia marina (formerly C. pacifica) KMM 3878 against human leukemia cells in vitro and the potential molecular mechanism underlying this activity. Our results showed that the CPS could inhibit the proliferation of HL-60 cells in a dose-dependent manner with no effect on normal PBMC cells. HL-60 cells treated with the CPS exhibited typical morphologic and biochemical signs of apoptosis. We found that the CPS caused the collapse of mitochondrial transmembrane potential (ΔΨm), activated caspases-8,-9, and − 3, decreased the ratio of anti-apoptotic Bcl-2 and pro-apoptotic Bax proteins, increased ROS production and TNF-α secretion, and stimulated phosphorylation of p38 MAPK and p53 in HL-60 cells. Taken together, these data suggest that both extracellular and intracellular signaling pathways contribute to the CPS-induced apoptosis in HL-60 cells.

RETRACTION: Antisense inhibition of Bcr-Abl/c-Abl synthesis promotes telomerase activity and upregulates tankyrase in human leukemia cells.

R. Bakalova, H. Ohba, Z. Zhelev, T. Kubo, M. Fujii, M. Ishikawa, Y. Shinohara, and Y. Baba, 'Antisense inhibition of Bcr-Abl/c-Abl synthesis promotes telomerase activity and upregulates tankyrase in human leukemia cells,' FEBS Letters 564, no. 1-2 (2004): 73-84, https://doi.org/10.1016/S0014-5793(04)00318-7. The above article, published online on 9 April 2004 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors; the journal Editor-in-Chief, Michael Brunner; FEBS Press; the National Institute of Advanced Industrial Science and Technology (AIST); and John Wiley and Sons Ltd. Following publication, concerns were raised by a third-party regarding several figures in the article. The subsequent institutional investigation conducted by the AIST revealed: Inappropriate duplication of image panels within the article, between the β-actin loading controls for 4 and 6 days in the Western blot of Fig. 2A K-562; between the subpanels of the electrophoresis blots in Fig. 4A K-562 and Jurkat cells; and between the subpanels of the electrophoresis blots in Fig. 6B. Band insertion in the Western blot of Fig. 6A p210 Bcr-Ab lane. Inappropriate duplication of images between this article (Fig. 2A K562 β-actin and Fig. 4B K562 6 days treatment bands) and an earlier publication from 2003 by an overlapping group of authors representing different experimental conditions. Inappropriate duplication and modification of an image between this article (Figure 3A2) and an earlier publication from 2004 by an overlapping group of authors representing different experimental conditions. Therefore, the conclusions of the paper are substantially compromised and the institute has recommended the paper to be retracted. The editors of the journal agree with the retraction based on the institutional investigation.

Pharmacological restriction of genomic binding sites redirects PU.1 pioneer transcription factor activity.

Transcription factor (TF) DNA-binding dynamics govern cell fate and identity. However, our ability to pharmacologically control TF localization is limited. Here we leverage chemically driven binding site restriction leading to robust and DNA-sequence-specific redistribution of PU.1, a pioneer TF pertinent to many hematopoietic malignancies. Through an innovative technique, 'CLICK-on-CUT&Tag', we characterize the hierarchy of de novo PU.1 motifs, predicting occupancy in the PU.1 cistrome under binding site restriction. Temporal and single-molecule studies of binding site restriction uncover the pioneering dynamics of native PU.1 and identify the paradoxical activation of an alternate target gene set driven by PU.1 localization to second-tier binding sites. These transcriptional changes were corroborated by genetic blockade and site-specific reporter assays. Binding site restriction and subsequent PU.1 network rewiring causes primary human leukemia cells to differentiate. In summary, pharmacologically induced TF redistribution can be harnessed to govern TF localization, actuate alternate gene networks and direct cell fate.

Novel alloxazine analogues: design, synthesis, and antitumour efficacy enhanced by kinase screening, molecular docking, and ADME studies

This study describes the development of novel alloxazine analogues as potent antitumor agents with enhanced selectivity for tumour cells. Twenty-nine out of 45 newly compounds were investigated in vitro for their growth inhibitory activities, against two human tumour cell lines, namely, the human T-cell acute lymphoblastoid leukaemia cell line (CCRF-HSB-2) and human oral epidermoid carcinoma cell line (KB), and the antitumor agent “Ara-C” was used as a positive reference in this investigation. Compounds 9e and 10J were the highest among their analogues, against both tumour cell lines (CCRF-HSB-2 and KB). Correlation analyses demonstrated a strong relationship between the IC50 values and AutoDock binding free energy or calculated inhibition (Ki ). The study delves into structure–activity relationships (SARs) through advanced modelling tools integrated with structure-based drug design (SBDD) using GOLD 5.2.2, AutoDock 4.2, and Accelrys Discovery Studio 3.5. Physicochemical properties, pharmacokinetics, drug-likeness, and toxicity predictions of the most potent alloxazine derivatives were conducted using ProTox-II and Swiss ADME for effective antitumor agents with improved selectivity.

Selective degradation of mutant FMS-like tyrosine kinase-3 requires BIM-dependent depletion of heat shock proteins

AbstractInternal tandem duplications in the FMS-like tyrosine kinase-3 (FLT3-ITD) are common mutations in acute myeloid leukemia (AML). Proteolysis-targeting chimeras (PROTACs) that induce proteasomal degradation of mutated FLT3 emerge as innovative pharmacological approach. Molecular mechanisms that control targeted proteolysis beyond the ubiquitin-proteasome-system are undefined and PROTACs are the only known type of FLT3 degraders. We report that the von-Hippel-Lindau ubiquitin-ligase based FLT3 PROTAC MA49 (melotinib-49) and the FLT3 hydrophobic tagging molecule MA50 (halotinib-50) reduce endoplasmic reticulum-associated, oncogenic FLT3-ITD but spare FLT3. Nanomolar doses of MA49 and MA50 induce apoptosis of human leukemic cell lines and primary AML blasts with FLT3-ITD (p < 0.05-0.0001), but not of primary hematopoietic stem cells and differentiated immune cells, FLT3 wild-type cells, retinal cells, and c-KIT-dependent cells. In vivo activity of MA49 against FLT3-ITD-positive leukemia cells is verified in a Danio rerio model. The degrader-induced loss of FLT3-ITD involves the pro-apoptotic BH3-only protein BIM and a previously unidentified degrader-induced depletion of protein-folding chaperones. The expression levels of HSP90 and HSP110 correlate with reduced AML patient survival (p < 0.1) and HSP90, HSP110, and BIM are linked to the expression of FLT3 in primary AML cells (p < 0.01). HSP90 suppresses degrader-induced FLT3-ITD elimination and thereby establishes a mechanistically defined feed-back circuit.

METTL3-mediated TIM1 promotes macrophage M1 polarization and inflammation through IGF2BP2-dependent manner.

Macrophage polarization and inflammation may play an important role in the development of sepsis. T-cell immunoglobulin mucin 1 (TIM1) has been demonstrated to promote macrophage inflammatory responses. However, whether TIM1 regulates macrophage polarization and inflammation to affect sepsis development remains unclear. Human monocytic leukemia cell line was induced into macrophages, followed by stimulated with LPS and IL-4 to induce M1 polarization and M2 polarization. The expression levels of TIM1, methyltransferase 3 (METTL3), and insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) were examined by qRT-PCR and western blot. IL-6, IL-1β, and TNF-α levels were tested by ELISA. CD86+cell rate was analyzed by flow cytometry. The m6A methylation level of TIM1 was assessed by MeRIP assay. The interaction of between TIM1 and METTL3 or IGF2BP2 was assessed by dual-luciferase reporter assay and RIP assay. TIM1 knockdown repressed LPS-induced macrophage M1 polarization and inflammation. In terms of mechanism, METTL3 promoted TIM1 expression through m6A modification, and this modification could be recognized by IGF2BP2. Besides, knockdown of METTL3/IGF2BP2 suppressed LPS-induced macrophage M1 polarization and inflammation, while this effect could be eliminated by TIM1 overexpression. METTL3/IGF2BP2/TIM1 axis promoted macrophage M1 polarization and inflammation, which might provide potential target for sepsis treatment.

Steroidal constituents in the whole plants of Helleborus niger and their cytotoxic activity in vitro

Phytochemical investigation of the whole plants of Helleborus niger L. (Ranunculaceae) resulted in the isolation of five undescribed compounds, including one bufadienolide (1), two bufadienolide rhamnosides (2 and 3), and two ecdysteroids (12 and 13), along with eight known compounds (4–11). The chemical structures of 1–3, 12, and 13 were determined by spectroscopic studies, including 2D NMR, and chromatographic and spectroscopic analyses of the hydrolyzed products. Compounds 1–13 were evaluated for their cytotoxic activity against HL-60 human leukemia cells, A549 human lung adenocarcinoma cells, SBC-3 human small-cell lung cancer cells, and TIG-3 human normal diploid lung cells. Compounds 1–12 showed cytotoxic activity against HL-60, A549, and SBC-3 cells, with IC50 values ranging from 0.0016 to 6.1 μM. Bufadienolide rhamnoside 2 exhibited potent cell proliferation inhibitory activity against SBC-3 cells after 24–48 h of treatment and apoptosis-inducing activity in SBC-3 cells via an intrinsic pathway after 72 h of treatment. The JFCR39 panel screening of 2 suggests that the molecular target of 2 is Na+,K+-ATPase.