Human Acute Myeloid Leukemia U937 Research Articles

Decoding the Mechanism of Shen Qi Sha Bai Decoction in Treating Acute Myeloid Leukemia Based on Network Pharmacology and Molecular Docking

Traditional Chinese Medicine (TCM) has been shown to be efficacious in treating leukemia for thousands of years. It has been shown that Shen Qi Sha Bai Decoction (SQSBD) has been extensively used in the treatment of acute myeloid leukemia (AML). However, the mechanism of SQSBD in treating AML remains unclear. In this study, we employed network pharmacology to analyze the potential active components and elucidate molecular mechanism of SQSBD in treating AML. A total of 268 active components were identified from SQSBD, among which 9 key components (Quercetin, luteolin, kaempferol, licochalcone A, formononetin, wogonin, β-sitosterol, oroxylin A, naringenin, and baicalein) were hit by the 6 hub targets (CDK1, MAPK1, JUN, PCNA, HSB1, STAT3) associated with leukemia. Molecular docking showed that two core active components, quercetin and licochalcone A, exhibited the highest component-like properties (DL), and could bind well to CDK1 and MAPK1 protein. The experimental validation of these two components showed that quercetin inhibited cell growth through CDK1 dephosphorylation-mediated cell cycle arrest at G2/M phase in human AML U937 and HL60 cells, and licochalcone A induced cell differentiation in these leukemia cells via activation of MAPK1 and upregulation of CD11b. All these results indicate that SQSBD is effective in the treatment of AML, and quercetin and licochalcone A are the major candidate compounds for AML treatment.

In vitro activity of some flavonoid derivatives on human leukemic myeloid cells: evidence for aminopeptidase-N (CD13) inhibition, antiproliferative and cell death properties

Leukemia cells from patients with acute myeloid leukemia (AML) display high proliferative capacity and are resistant to death. Membrane-anchored aminopeptidase-N/CD13 is a potential drug target in AML . Clinical research efforts are currently focusing on targeted therapies that induce death in AML cells. We previously developed a non-cytotoxic APN/CD13 inhibitor based on flavone-8-acetic acid scaffold, the 2',3-dinitroflavone-8-acetic acid (1) . In this context, among the variously substituted 113 compounds further synthesized and tested for evaluation of their effects on APN/CD13 activity, proliferation and survival in human AML U937 cells, eight flavonoid derivatives emerged: 2',3-dinitro-6-methoxy-flavone-8-acetic acid ( 2 ), four compounds ( 3 – 6 ) with the 3-chloro-2,3-dihydro-3-nitro-2-phenyl-4 H -1-benzopyran-4-one structure, and three ( 7 – 9 ) with the 3-chloro-3,4-dihydro-4-hydroxy-3-nitro-2-phenyl-2 H -1-benzopyran framework. Different structure-activity relationships were observed between APN/CD13 activity and growth/survival processes. We showed that compound 2 , but not benzopyran derivatives 3 – 9 , inhibited APN activity (although to a less degree than 1) . Both 1 and 2 did not affect AML cell proliferation and survival, indicating that CD13’s APN activity is not required for these processes. In contrast, benzopyran compounds 3 – 9 inhibited in a concentration-dependent manner the growth of U937 cells by inducing death as evidenced by phosphatidylserine externalization. Cell death was associated with the presence of geminal nitro group and chlorine at the 3-position of the 2 H -1-benzopyran scaffold. The presence of other substituents such as CH 2 COOH or CH 2 CH=CH 2 groups at the 8-position, NO 2 or I substituents at the 2'- or 3'-position, OCH 3 or OCH 2 C 6 H 5 groups at the 4'-position did not affect cell death. Importantly, the inhibitory effects evidenced with compounds 7 – 9 were not due to their potential decomposition into the corresponding ( Z )-(2chloro-2-nitroethenyl)benzene and salicylaldehyde. Based on these preliminary data, the 3-chloro,3-nitro-2 H -1-benzopyran derivatives could be classified as a new group of compounds with promising antitumor properties; this study therefore provides the opportunity to explore their potential efficiency in AML patients’ cells ex vivo .

PU.1 affects proliferation of the human acute myeloid leukemia U937 cell line by directly regulating MEIS1.

The transcription factor PU.1 is a member of the ETS family, which is expressed in a wide variety of hematopoietic lineages. Accumulating evidence has indicated that PU.1 plays a key role in hematopoiesis, and reduced expression of PU.1 leads to the pathogenesis of human myeloid leukemia. As a multi-functional factor, PU.1 is also required for mixed lineage leukemia (MLL) stem cell potential and the development of MLL. However, the function of PU.1 in human non-MLL leukemia and its molecular mechanism remains poorly understood. In the present study, PU.1 siRNA was demonstrated to efficiently inhibit the transcription level of oncogene MEIS1 in the human acute myeloid non-MLL leukemia U937 cell line. In addition, PU.1, as a positive regulator of MEIS1, performed a crucial role in maintaining cell proliferation. Using electrophoretic mobility shift assay, chromatin immunoprecipitation analysis and luciferase reporter assay, previously unexplored evidence that PU.1 activated the MEIS1 promoter through a conserved binding motif in vitro and in vivo was further defined. Overall, the present study provides insight into the molecular mechanism of the contribution of PU.1 to the pathogenesis of non-MLL U937 cells, which is mediated by direct regulation of MEIS1 transcription. The present data reveal the possibility of developing an alternative therapy for non-MLL leukemia by targeting PU.1-mediated MEIS1 gene activation.

Tert‐Butylcarbamate‐Containing Histone Deacetylase Inhibitors: Apoptosis Induction, Cytodifferentiation, and Antiproliferative Activities in Cancer Cells

Herein we report novel pyrrole- and benzene-based hydroxamates (8, 10) and 2'-aminoanilides (9, 11) bearing the tert-butylcarbamate group at the CAP moiety as histone deacetylase (HDAC) inhibitors. Compounds 8 b and 10 c selectively inhibited HDAC6 at the nanomolar level, whereas the other hydroxamates effected an increase in acetyl-α-tubulin levels in human acute myeloid leukemia U937 cells. In the same cell line, compounds 8 b and 10 c elicited 18.4 and 21.4 % apoptosis, respectively (SAHA: 16.9 %), and the pyrrole anilide 9 c displayed the highest cytodifferentiating effect (90.9 %). In tests against a wide range of various cancer cell lines to determine its antiproliferative effects, compound 10 c exhibited growth inhibition from sub-micromolar (neuroblastoma LAN-5 and SH-SY5Y cells, chronic myeloid leukemia K562 cells) to low-micromolar (lung H1299 and A549, colon HCT116 and HT29 cancer cells) concentrations. In HT29 cells, 10 c increased histone H3 acetylation, and decreased the colony-forming potential of the cancer cells by up to 60 %.

Copper ions regulate cytotoxicity of disulfiram to myeloid leukemia cells

White blood cell (WBC) count is considered a prognostic risk factor in acute myeloid leukemia. As density of leukemic cells increases, the cytotoxic activity of certain anticancer drugs, such as vincristine and doxorubicin, progressively decreases. In this study, we investigated the cell density-dependent induction of apoptosis of human acute myeloid leukemia U937 and ML-1 cells by disulfiram (DSF), the dithiocarbamate drug recently proposed for treatment of human cancers. This effect is dependent on uptake of extracellular copper and its intracellular accumulation. High-density cells cannot uptake and accumulate this metal to a sufficient level that would allow induction of apoptosis due to progressive decrease of its extracellular concentration. Simple addition of copper can resume sensitivity of high-density leukemic cells to DSF and improve efficiency of anti-leukemic therapies using this drug, thus providing benefit to patients with high WBC count.

TPCK Induces Apoptosis in Human Acute Myeloid Leukemia U-937 Cells.

Many types of antitumor therapy in general and AML in particular exert their effect by activating apoptosis. Apoptosis of AML cells can be induced by cytostatic drugs, corticosteroids, and radiation. Recently, the role of different proteases as possible targets for chemotherapy was described. N-tosyl-L-phenylalanine chloromethyl ketone (TPCK), a chymotrypsin-like protease (CLP) inhibitor was shown to exert a dual effect on leukemic cells: proapoptotic and antiapoptotic. In the present study the mechanism of its proapoptotic effect was addressed. It was found that the CLP inhibitors, TPCK and 3,4 dichloroisicoumarine induced apoptosis in a time- and concentration-dependent manner. Apoptosis was accompanied by a decrease in mitochondrial membrane potential, cytochrome c release, caspase-3 (but not caspase-8) activation, PS flip-flop (measured by Annexin-V staining followed by flow cytometry analysis) and chromatin condensation, but not fragmentation (detected by acridine orange/ethidium bromide staining).All apoptotic processes induced by TPCK were completely inhibited by cycloheximide. The ability of cycloheximide to inhibit TPCK-induced cell death suggests that protein synthesis plays a role in TPCK-induced apoptosis. Additionaly, the proapoptotic effect of TPCK was abolished by elimination of glucose from the medium. The data supports the role of mitochondria in this process.In the present study the apoptotic pathway driven by inhibition of CLP was demonstrated. Moreover, these findings suggest possible ways of preventing the proapoptotic activity of TPCK and thereby enhancimg its antiapoptotic action.