Selective eradication of venetoclax-resistant monocytic acute myeloid leukemia with iron oxide nanozymes.

The clinical treatment of human acute myeloid leukemia (AML) is rapidly progressing from chemotherapy to targeted therapies led by the BCL-2 inhibitor venetoclax (VEN). Despite its unprecedented success, VEN still encounters clinical resistance. Thus, uncovering the biological vulnerability of VEN-resistant AML disease and identifying effective therapies to treat them are urgently needed. We have previously demonstrated that iron oxide nanozymes (IONE) are capable of overcoming chemoresistance in AML. The current study reports a new activity of IONE in overcoming VEN resistance. Specifically, we revealed an aberrant redox balance with excessive intracellular reactive oxygen species (ROS) in VEN-resistant monocytic AML. Treatment with IONE potently induced ROS-dependent cell death in monocytic AML in both cell lines and primary AML models. In primary AML with developmental heterogeneity containing primitive and monocytic subpopulations, IONE selectively eradicated the VEN-resistant ROS-high monocytic subpopulation, successfully resolving the challenge of developmental heterogeneity faced by VEN. Overall, our study revealed an aberrant redox balance as a therapeutic target for monocytic AML and identified a candidate IONE that could selectively and potently eradicate VEN-resistant monocytic disease.

A rare KMT2A::CBL transcript in an acute monoblastic leukemia patient with an unfavorable outcome.

BACKGROUND: Lysine [K] methyltransferase 2A (KMT2A, previously known as MLL) gene rearrangements are common in acute leukemias of various lineages and are associated with features such as chemotherapy resistance and rapid relapse. KMT2A::CBL is a rare fusion of unknown pathogenesis generated by a unique interstitial deletion of chromosome 11 that has been reported across a wide age range in both acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) patients. The leukemogenic effect of the KMT2A::CBL rearrangement and its association with clinical prognosis have not been well clarified. METHODS AND RESULTS: We report the case of a 64-year-old female who was diagnosed with acute monoblastic leukemia (M5a) and who acquired the rare KMT2A::CBL fusion. The patient received multiple cycles of therapy but did not achieve remission and eventually succumbed to severe infection and disease progression. Additionally, we characterized the predicted KMT2A-CBL protein structure in this case to reveal the underlying leukemogenic mechanisms and summarized reported cases of hematological malignancies with KMT2A::CBL fusion to investigate the correlation of gene rearrangements with clinical outcomes. CONCLUSIONS: This report provides novel insights into the leukemogenic potential of the KMT2A::CBL rearrangement and the correlation between gene rearrangements and clinical outcomes.

Leukemia Cutis With Histopathologic and Immunophenotypic Features Resembling S100-Negative CD1a-Positive Cutaneous Histiocytosis.

ABSTRACT: S100-negative CD1a-positive cutaneous histiocytosis is an exceedingly rare histiocytosis that is defined histopathologically by a dense dermal infiltrate of ovoid mononuclear cells with grooved nuclei and ample cytoplasm with variable nuclear atypia and mitoses that are immunohistochemically positive for CD1a and negative for S100 and CD207 (langerin). The histogenesis of S100-negative CD1a-positive histiocytosis is unclear, and its precursor cell has yet to be characterized. Although all cases thus far have been described as benign and occasionally self-resolving, the clinical course and outcome of this disease are not fully understood. This case expands the spectrum of disease associated with S100-negative CD1a-positive histiocytosis given its malignant course.

LINC00449 regulates the proliferation and invasion of acute monocytic leukemia and predicts favorable prognosis.

Acute myeloid leukemia (AML) is a highly aggressive disease that causes high mortality. Long noncoding RNA (lncRNA) have studied in recent years that could be a potential biomarker and therapeutic target. Therefore, it is urgently necessary to explore the novel lncRNAs in AML. Microarray analysis was performed to determine the differentially expressed lncRNAs between mononuclear cells of AML and normal samples. The biological function of lncRNA on cell proliferation and migration was measured in vitro. The predicted downstream target of lncRNA was validated by dual-luciferase reporter assay, RNA immunoprecipitation, RNA pull-down, and rescue experiments. The tumor formation and metastasis study were conducted in vivo. The expression of lncRNA in clinical samples was determined by a quantitative reverse transcription-polymerase chain reaction. LINC00449 was one of the most differentially expressed lncRNA which is mainly located in the cytoplasm. We found that overexpression of LINC00449 could inhibit the cell proliferation and invasion of AML cells in vitro and in vivo. Besides, miR-150 was identified as the downstream target gene that was negatively regulated by LINC00449 and FOXD3 was targeted by miR-150. The results were confirmed by dual-luciferase reporter assay, RNA immunoprecipitation, RNA pull-down, rescue experiments, and in vivo assays. Patients with AML with high expression of LINC0049 may characterize a favorable survival. All the above-mentioned findings indicated that the LINC00449/miR-150/FOXD3 signaling pathway might represent a novel prognostic biomarker or therapeutic target for the treatment of AML.

PFKFB4 is critical for the survival of acute monocytic leukemia cells.

Acute myeloid leukemia (AML), which is characterized by an overproliferation of blood cells, is divided into several subtypes in adults and children. Of those subtypes, acute monocytic leukemia (M4/M5, AMoL) is reported to be associated with abnormal gene fusions that result in monocytic cell differentiation being blocked. However, few studies have shown a relationship between cellular metabolism and the initiation of AMoL. Here, we use the open-access database TCGA to analyze the expression of enzymes in the metabolic cycle and find that PFKFB4 is highly expressed in AMoL. Subsequently, knocking down PFKFB4 in THP-1 and U937 cells significantly inhibits cell growth and increases the sensitivity of cells to chemical drug-induced apoptosis. In line with the gene-editing alterations, treatment with a PFKFB4 inhibitor exhibits similar effects on THP-1 and U937 proliferation and apoptosis. In addition, we find that PFKFB4 functions as a reliable target of the epigenetic regulator MLL, which is a well-known modulator in AMoL. Mechanistically, MLL promotes PFKFB4 expression at the transcriptional level through the putative E2F6 binding site in the promoter of the pfkfb4 gene. Taken together, our results suggest PFKFB4 serves as a downstream target of MLL and functions as a potent therapeutic target in AMoL.

Anisotropic Platinum Nanoparticle-Induced Cytotoxicity, Apoptosis, Inflammatory Response, and Transcriptomic and Molecular Pathways in Human Acute Monocytic Leukemia Cells.

The thermoplasmonic properties of platinum nanoparticles (PtNPs) render them desirable for use in diagnosis, detection, therapy, and surgery. However, their toxicological effects and impact at the molecular level remain obscure. Nanotoxicology is mainly focused on the interactions of nanostructures with biological systems, particularly with an emphasis on elucidating the relationship between the physical and chemical properties such as size and shape. Therefore, we hypothesized whether these unique anisotropic nanoparticles could induce cytotoxicity similar to that of spherical nanoparticles and the mechanism involved. Thus, we synthesized unique and distinct anisotropic PtNPs using lycopene as a biological template and investigated their biological activities in model human acute monocytic leukemia (THP-1) macrophages. Exposure to PtNPs for 24 h dose-dependently decreased cell viability and proliferation. Levels of the cytotoxic markers lactate dehydrogenase and intracellular protease significantly and dose-dependently increased with PtNP concentration. Furthermore, cells incubated with PtNPs dose-dependently produced oxidative stress markers including reactive oxygen species (ROS), malondialdehyde, nitric oxide, and carbonylated protein. An imbalance in pro-oxidants and antioxidants was confirmed by significant decreases in reduced glutathione, thioredoxin, superoxide dismutase, and catalase levels against oxidative stress. The cell death mechanism was confirmed by mitochondrial dysfunction and decreased ATP levels, mitochondrial copy numbers, and PGC-1α expression. To further substantiate the mechanism of cell death mediated by endoplasmic reticulum stress (ERS), we determined the expression of the inositol-requiring enzyme (IRE1), (PKR-like ER kinase) PERK, activating transcription factor 6 (ATF6), and activating transcription factor 4 ATF4, the apoptotic markers p53, Bax, and caspase 3, and the anti-apoptotic marker Bcl-2. PtNPs could activate ERS and apoptosis mediated by mitochondria. A proinflammatory response to PtNPs was confirmed by significant upregulation of interleukin-1-beta (IL-1ß), interferon γ (IFNγ), tumor necrosis factor alpha (TNFα), and interleukin (IL-6). Transcriptomic and molecular pathway analyses of THP-1 cells incubated with the half maximal inhibitory concentration (IC50) of PtNPs revealed the altered expression of genes involved in protein misfolding, mitochondrial function, protein synthesis, inflammatory responses, and transcription regulation. We applied transcriptomic analyses to investigate anisotropic PtNP-induced toxicity for further mechanistic studies. Isotropic nanoparticles are specifically used to inhibit non-specific cellular uptake, leading to enhanced in vivo bio-distribution and increased targeting capabilities due to the higher radius of curvature. These characteristics of anisotropic nanoparticles could enable the technology as an attractive platform for nanomedicine in biomedical applications.

Curcumin inhibited the growth and invasion of human monocytic leukaemia SHI-1 cells in vivo by altering MAPK and MMP signalling.

Context: Curcumin, a polyphenolic compound extracted from the rhizome of the tropical plant Curcuma longa L. (Zingiberaceae), has been considered as a cancer chemopreventive drug by American National Cancer Institute.Objective: To examine the effect of curcumin on acute monocytic leukaemia SHI-1 cells in vivo.Materials and methods: The SHI-1 cells (1 × 106 cells in 0.1 mL PBS) were injected subcutaneously into the right flanks of the female SCID mice. Curcumin dissolved in olive oil (15 and 30 mg/kg) was administered (i.p.) to mice once a day for 15 days while the control group received olive oil injection. Tumour proliferation and apoptosis were examined by PCNA, TUNEL and cleaved caspase-3 staining. The expression of MAPK, NF-κB, MMP9, MMP2 and vimentin were confirmed by RT-PCR, immunohistochemistry or western blotting.Results: Administration of curcumin significantly inhibited tumour growth, as the tumour weight decreased from 0.67 g (control) to 0.47 g (15 mg/kg) and 0.35 g (30 mg/kg). Curcumin inhibited the expression of PCNA and increased the degree of TUNEL and cleaved caspase-3 staining in tumour tissue. The results of western blotting showed that curcumin treatment inhibited NF-κB and ERK signalling while activating p38 and JNK. Moreover, curcumin attenuated the mRNA transcription and protein expression of MMP2 and MMP9. Curcumin also suppressed the level of vimentin.Discussion and conclusions: Our study demonstrates that curcumin can inhibit the growth and invasion of human monocytic leukaemia in vivo, suggesting the possible use of curcumin for anti-metastasis in leukaemia and the value of determining its unique target.

Tryptophanyl-tRNA synthetase mediates high-affinity tryptophan uptake into human cells.

The tryptophan (Trp) transport system has a high affinity and selectivity toward Trp, and has been reported to exist in both human and mouse macrophages. Although this system is highly expressed in interferon-γ (IFN-γ)-treated cells and indoleamine 2,3-dioxygenase 1 (IDO1)-expressing cells, its identity remains incompletely understood. Tryptophanyl-tRNA synthetase (TrpRS) is also highly expressed in IFN-γ-treated cells and also has high affinity and selectivity for Trp. Here, we investigated the effects of human TrpRS expression on Trp uptake into IFN-γ-treated human THP-1 monocytes or HeLa cells. Inhibition of human TrpRS expression by TrpRS-specific siRNAs decreased and overexpression of TrpRS increased Trp uptake into the cells. Of note, the TrpRS-mediated uptake system had more than hundred-fold higher affinity for Trp than the known System L amino acid transporter, promoted uptake of low Trp concentrations, and had very high Trp selectivity. Moreover, site-directed mutagenesis experiments indicated that Trp- and ATP-binding sites, but not tRNA-binding sites, in TrpRS are essential for TrpRS-mediated Trp uptake into the human cells. We further demonstrate that the addition of purified TrpRS to cell culture medium increases Trp uptake into cells. Taken together, our results reveal that TrpRS plays an important role in high-affinity Trp uptake into human cells.

The outer membrane protein Tp92 of Treponema pallidum induces human mononuclear cell death and IL-8 secretion.

Treponema pallidum is the pathogen that causes syphilis, a sexually transmitted disease; however, the pathogenic mechanism of this organism remains unclear. Tp92 is the only T. pallidum outer membrane protein that has structural features similar to the outer membrane proteins of other Gram-negative bacteria, but the exact functions of this protein remain unknown. In the present study, we demonstrated that the recombinant Tp92 protein can induce human mononuclear cell death. Tp92 mediated the human monocytic cell line derived from an acute monicytic leukemia patient (THP-1) cell death by recognizing CD14 and/or TLR2 on cell surfaces. After the stimulation of THP-1 cells by the Tp92 protein, Tp92 may induce atypical pyroptosis of THP-1 cells via the pro-caspase-1 pathway. Meanwhile, this protein caused the apoptosis of THP-1 cells via the receptor-interacting protein kinase 1/caspase-8/aspase-3 pathway. Tp92 reduced the number of monocytes among peripheral blood mononuclear cells. Interestingly, further research showed that Tp92 failed to increase the tumour necrosis factor-α, interleukin (IL)-1ß, IL-6, IL-10, IL-18 and monocyte chemotactic protein 1 (MCP)-1 levels but slightly elevated the IL-8 levels via the Nuclear Factor (NF)-κB pathway in THP-1 cells. The data suggest that Tp92 recognizes CD14 and TLR2, transfers the signal to a downstream pathway, and activates NF-κB to mediate the production of IL-8. This mechanism may help T. pallidum escape recognition and elimination by the host innate immune system.

Induction of apoptosis in human acute monocytic leukemia (THP-1) cells with NaF and the related mechanisms.

PURPOSE: Acute monocytic leukemia remains a big challenge, and there are a series of non-specific esterases which can be inhibited by sodium fluoride (NaF) in mononuclear cells, providing insights into the leukemia targeted therapy. In this study, the apoptotic effect of NaF with human mononuclear leukemia THP-1 cells and the inhibition of α-naphthol acetate esterase (α-NAE) activity, and also the potentially underlying mechanisms were investigated. METHODS: THP-1 cells were cultured with different concentrations of NaF (0, 0.5, 1, 2, 4, 8 mM) for 24, 48 and 72 hrs. The α-NAE staining and chromogenic method were used to detect the activation of α-NAE. The 3-(4, 5-dimethylthiazol-2-yl)-2), 5-diphenyltetrazolium bromide (MTT) assay was used to detect the antitumor effect of NaF on THP-1 cells in vitro. Flow cytometry was used to observe the apoptotic ratio following treatment with NaF in THP-1 cells. The mRNA levels of mammalian target of Bcl-2 and Bax were detected pre and post-NaF treatment using reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The generation of depression effects of THP-1 cells cultured in vitro were detected using MTT technology, which revealed a dose- and time-dependent association. After 24hrs of exposure to NaF at greater than 1mmol/L, typical apoptotic changes were observed, accompanied by the α-NAE positive reaction and decreased intensity. The IC50 was 4 mmol/L at 24hrs. Flow cytometric analysis indicated that treatment with NaF at concentrations of 2, 4 and 8 mmol/L increased the apoptotic rate of THP-1 cells. RT-PCR indicated that NaF upregulated the gene expression of Bax and downregulated the expression of Bcl-2. CONCLUSION: NaF inhibited the proliferation of THP-1 cells and the activation of α-NAE by adversely regulating the expression of Bax and Bcl-2.

Sodium azide suppresses LPS-induced expression MCP-1 through regulating IκBζ and STAT1 activities in macrophages.

Sodium azide (NaN3) is a chemical compound with multiple toxic effects on vascular and neuronal systems, causing hypotension and neurotoxicity, respectively. In order to test its effects on the immune system, human and mouse macrophage-like cell lines were treated with nontoxic doses of NaN3 and the changes in LPS-induced inflammatory activation was measured. Interestingly, the LPS-induced expression of monocyte chemoattractant protein (MCP)-1 was suppressed by NaN3 without affecting the expression of IL-8 and TNF-α. Further analysis of cellular signaling mediators involved in the expression of these cytokines revealed that NaN3 suppressed the LPS-induced activation of signal transducers and activator of transcription (STAT)1 and inhibitor of κB (IκB) ς, which are involved in the LPS-induced expression of MCP-1, while the LPS-induced activation of nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) was not affected. The LPS-induced expression of MCP-2 and CXCL10, which are also regulated by STAT1, was suppressed by NaN3. Similarly, the LPS-induced expression of IL-6, which is regulated by IκBζ, was suppressed by NaN3. These results demonstrate that NaN3 selectively suppresses the LPS-induced expression of pro-inflammatory mediators through the suppression of STAT1 and IκBζ activation. These new findings about the activity of NaN3 may contribute to the development of specific regulators of macrophage activity during acute and chronic inflammation.

Enlightenment and lesson from the successful treatment of acute superior mesenteric artery embolism.

 Despite recent advances, treatment of acute superior mesenteric artery embolism (SMAE) in emergency is still very difficult. The comparative rarity, the difficulty of early diagnosis, and the extremely high mortality of SMAE give us the sufficient reasons to report our successful experience in curing a patient with acute SMAE. In the present case, the patient was diagnosed early without evidence of intestinal necrosis. The diagnosis of SMAE was verified by computed tomography angiography (CTA). A comprehensive treatment was immediately employed including a combination of intra-arterial thrombolysis and embolectomy operation with emergent laparotomy. We summarize that the successful treatment of superior mesenteric artery embolism depends on early diagnosis and timely reestablishment of arterial flow under the support of general treatments such as prevention of sepsis and control of organic insufficiencies. Through a combined treatment, patient's life could be saved without complications.

mRNA expression profiling of histone modifying enzymes in pediatric acute monoblastic leukemia.

Histone modification is dysregulated in various types of cancers, including hematological malignancies. However, the expression profile of histone-modifying enzymes in pediatric acute monoblastic leukemia (AML FAB M5) has not been investigated. In this study, we evaluated the mRNA expression profile of 85 genes that encode enzymes involved in histone-modification in 27 pediatric AML FAB M5 samples by using a novel real-time PCR array. We obtained a gene cluster consisting of a total of 28 genes (15 up-regulated genes and 13 down-regulated genes). This gene signature revealed up-regulated expression of putative oncogenes GCN5L2, SETD8, KDM5C, AURKA and AURKB, and downregulated putative tumor suppressor genes (TSGs) EP300, PRMT3, PRMT8 and NOTCH2. We investigated possible biological interactions between differentially expressed genes using ingenuity pathway analysis (IPA) and found 12 significant networks. Among these, gene expression, cancer, and embryonic development showed the highest number of networks with 39 focus molecules and had an associated significance score of 68. Further, Rb, CDKN2C, and E2F1 were found to be upstream regulators of histone-modifying enzymes. This study provides additional insights into the molecular pathogenesis of pediatric AML FAB M5. These genes represent interesting targets with potential for diagnostic, prognostic and therapeutic application in pediatric AML patients.

[Congenital leukemia showing lineage switch following induction chemotherapy and attaining long-term remission after HLA-haploidentical stem cell transplantation].

Congenital leukemia is a rare subgroup of childhood leukemia. Lineage switches in leukemic cells are relatively rare events, which have been occasionally reported in congenital leukemia. To the best of our knowledge, the survival of congenital leukemia patients with lineage switch has not been previously documented. This lack of documentation may be attributable to extremely poor prognosis of these patients. We describe a case of a newborn female with initial diagnosis of MLL-AF4 positive B-precursor acute lymphoblastic leukemia, who developed lineage switch to acute monocytic leukemia following the induction therapy. Although morphological remission was temporary, she received an HLA-haploidentical bone marrow transplant from her father with non-remission status because of an early relapse at the age of 4 months. Despite many difficulties such as graft-versus-host disease, growth impairment, and psychomotor retardation, she remained in remission for 3 years and 7 months after the transplant. This successful outcome suggests that the graft-versus-leukemia effect was potentially accomplished in the patient. Taken together, early HLA-haploidentical stem cell transplant following remission is required for congenital leukemia patients with lineage switch, and it may be an effective alternative for refractory patients.

Bioassay-Guided Fractionation and In Vitro Antiproliferative Effects of Fractions of Artemisia nilagirica on THP-1 cell line.

ABSTACT Artemisia nilagirica (Clarke) is a widely used medicinal herb in Indian traditional system of medicine. Therefore, the present study was designed to evaluate the effects of A. nilagirica extracts/fractions on inhibition of proliferation and apoptosis in a human monocytic leukemia (THP-1) cell line. The crude extracts (A. nilagirica ethyl acetate extract [ANE] and A. nilagirica methanolic extract [ANA]) showed cytotoxic activity toward THP-1 cells with the IC50 values of 38.21 ± 7.37 and 132.41 ± 7.19 µg/ml, respectively. However, the cytotoxic activity of active fractions (ANE-B and ANM-9) obtained after column chromatography was found to be much more pronounced than their parent extracts. The IC50 values of ANE-B and ANM-9 were found to be 27.04 ± 2.54 µg/ml and 12.70 ± 4.79 µg/ml, respectively, suggesting greater susceptibility of the malignant cells. Cell cycle analysis and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end-labeling (TUNEL) assay revealed that inhibition of cell growth by A. nilagirica fractions on THP-1 cells was mediated by apoptosis. Active fractions of A. nilagirica increased the expression levels of caspase-3, -7, and poly-ADP-ribose polymerase (PARP), a critical member of the apoptotic pathway. These results suggested that active fractions of A. nilagirica may play a promising role in growth suppression by inducing apoptosis in human monocytic leukemic cells via mitochondria-dependent and death receptor-dependent apoptotic pathways.

Polydatin Induces Apoptosis and Inhibits Growth of Acute Monocytic Leukemia Cells.

Polydatin (PD), a component isolated from Polygonum cuspidatum, has various activities such as inhibiting platelet aggregation, lowering level of blood lipid, reducing lipid peroxidation, and so on. However, the antitumor activity of PD has been poorly reported. In the present study, effect of PD on cell proliferation was evaluated by Cell Counting Kit-8, and cell cycle and apoptosis were investigated by flow cytometry. Meanwhile, the protein expression level of Bc1-2, Bax, cyclin A, cyclin B, and cyclin D1, which associated with apoptosis and cell cycle were analyzed by Western blotting. Results show that PD could effectively inhibit the growth, arrest cells in S phase, and induce apoptosis of acute monocytic leukemia cell line THP-1; meanwhile, expression of cyclin D1 and Bc1-2 decreased significantly, and expression of Bax and cyclin A increased notably. All results suggest that PD maybe a potential therapeutic strategy for acute monocytic leukemia.