Myeloid Leukemia Cell Line HL-60 Research Articles

Effect of plasminogen activator urokinase receptor gene on the activation and apoptosis of neutrophil

Objective: To investigate the effect of plasminogen activator urokinase receptor (PLAUR) gene on neutrophil activation and apoptosis in neutrophil-like cell model. Methods: Human acute myeloid leukemia cell line HL60 was cultured in vitro and induced to differentiate into neutrophil-like cells by all-trans retinoic acid (ATRA). Lentiviral vectors interfering with human PLAUR gene was constructed and transfected into neutrophil-like cells (siRNA group). The phosphate buffer saline (PBS) group (untransfected neutrophil-like cells) and normal blank control group (NC group) (neutrophil-like cells transfected with blank plasmid) were used as controls (n=3). After starvation culture and addition of interleukin-17 afterwards in these 3 groups, the expression of CD11b on the cell membrane was detected by flow cytometry, and the levels of myeloperoxide (MPO) and extracellular neutrophil traps (NETs) in the supernatant were detected by enzyme-linked immunosorbent assay (ELISA) to investigate the activation of neutrophil-like cells. The apoptosis was detected by flow cytometry with annexin V/propidium iodide (PI) double staining and the expressions of apoptosis-related proteins caspase-3, bax and bcl-2 were detected by Western blotting. Results: The expression of CD11b in siRNA group (32.37±8.17) was lower than that in PBS group (46.27±1.54) and NC group (53.07±8.14) (P<0.05) by flow cytometry. The levels of MPO and NETs (33.37±1.11, 57.69±3.03) in the supernatant of siRNA group were significantly lower than those in PBS group (41.64±2.20, 77.60±4.33) and NC group (40.84±5.11, 76.15±2.10) (P<0.05). Flow cytometry with annexin V/PI showed that the expression of apoptosis in siRNA group (20.42%±2.45%) was significantly higher than that in PBS group (11.91%±2.23%) and NC group (11.13%±2.56%) (P<0.05). The relative expression of caspase-3 protein and bax protein (0.84±0.05, 0.83±0.04) in siRNA group was significantly higher than that in PBS group (0.68±0.02, 0.63±0.08) and NC group (0.71±0.01, 0.66±0.10) (P<0.05), and the relative expression of anti-apoptosis protein bcl-2 decreased in siRNA group (0.38±0.02) than in PBS group (0.73±0.05) and NC group (0.69±0.06) (P<0.05). Conclusion: PLAUR promotes the activation of neutrophil-like cells and inhibits the apoptosis.

Effect of Inhibiting SIX1 Expression on Drug-resistance of Acute Myeloid Leukemia Cell Line HL-60/ADR Cells

To establish HL-60 cells and adriamycin resistant HL-60 cells (H-60/ADR) in which the expression of homologous box gene 1 (SIX1) was inhibited, and investigate the effect of inhibiting the expression of SIX1 on the drug resistance. Lentivirus was used to transfect HL-60 and HL-60/ADR cells, and the cell lines stably inhibiting the expression of SIX1 were screened by puromycin. CCK-8 assay was used to detect the proliferation ability of cells in each group, apoptosis kit was used to detect the cell apoptosis, and real-time quantitative PCR was used to detect the expression level of drug-resistant related genes. HL-60 and HL-60/ADR stably transfected cell lines with down-regulation of SIX1 expression were successfully constructed. Compared with control group, the inhibition of SIX1 expression significantly inhibited the proliferation of HL-60 and HL-60/ADR cells (P <0.05), increased the apoptosis rate (P <0.05), and the sensitivity of cells to adriamycin increased after inhibition of SIX1 expression. Inhibition of SIX1 expression can improve cell sensitivity to adriamycin, and its role in reversing drug resistance may be related to the promotion of apoptosis gene expression.

Novel indole retinoid derivative induces apoptosis and cell cycle arrest and modulates AKT and ERK signaling in HL-60 cells.

Chemotherapy with targeted drugs is the first line therapy option for acute and chronic myeloid leukemia. However, hematopoietic stem cell transplantation may be used in high-risk patients or patients with failed responses to chemo drugs. Discovery and development of more effective new agents with lower side effects is the main aim of leukemia treatment. In this study, a novel retinoid compound with tetrahydronaphthalene ring was synthesized and evaluated for anticancer activity in human chronic and acute myeloid leukemia cell lines K562 and HL-60. Novel N-(1H-indol-1-yl)-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene-2-carboxamide was synthesized based on molecular hybridization of the two different bioactive structures retinoid head and indole. The effects of the synthesized carboxamide compound, which was referred to as compound 5, were determined in K562 chronic myeloid leukemia and HL-60 acute myeloid leukemia cell lines and L929 fibroblast cell line, which served as a control. Colorimetric MTT and caspase3 activity tests, flow cytometry, western blot, and microscopic examinations were used to evaluate biological activity. Compound 5 more effectively induced cell death in HL60 cells in comparison to K562 cells and L929 fibroblast cells. Therefore, further mechanism of cell death was investigated in HL60 cell line. It was found that compound 5 induced remarkable cytotoxicity, caspase3 activation, and PARP fragmentation in HL60 cells. Flow cytometric staining showed that the percentage of cells arrested in G0/G1 was also increased with compound 5 treatment. Important modulator proteins of cell proliferation p-ERK, p-AKT, and p-m-TOR were also found to be inhibited with compound 5 treatment. Collectively, our results reveal compound 5, which is a novel indole retinoid compound as a potential active agent for the treatment of acute promyelocytic leukemia.

Novel Insights into the Role of Kras in Myeloid Differentiation: Engaging with Wnt/β-Catenin Signaling.

Cells of the HL-60 myeloid leukemia cell line can be differentiated into neutrophil-like cells by treatment with dimethyl sulfoxide (DMSO). The molecular mechanisms involved in this differentiation process, however, remain unclear. This review focuses on the differentiation of HL-60 cells. Although the Ras proteins, a group of small GTP-binding proteins, are ubiquitously expressed and highly homologous, each has specific molecular functions. Kras was shown to be essential for normal mouse development, whereas Hras and Nras are not. Kras knockout mice develop profound hematopoietic defects, indicating that Kras is required for hematopoiesis in adults. The Wnt/β-catenin signaling pathway plays a crucial role in regulating the homeostasis of hematopoietic cells. The protein β-catenin is a key player in the Wnt/β-catenin signaling pathway. A great deal of evidence shows that the Wnt/β-catenin signaling pathway is deregulated in malignant tumors, including hematological malignancies. Wild-type Kras acts as a tumor suppressor during DMSO-induced differentiation of HL-60 cells. Upon DMSO treatment, Kras translocates to the plasma membrane, and its activity is enhanced. Inhibition of Kras attenuates CD11b expression. DMSO also elevates levels of GSK3β phosphorylation, resulting in the release of unphosphorylated β-catenin from the β-catenin destruction complex and its accumulation in the cytoplasm. The accumulated β-catenin subsequently translocates into the nucleus. Inhibition of Kras attenuates Lef/Tcf-sensitive transcription activity. Thus, upon treatment of HL-60 cells with DMSO, wild-type Kras reacts with the Wnt/β-catenin pathway, thereby regulating the granulocytic differentiation of HL-60 cells. Wild-type Kras and the Wnt/β-catenin signaling pathway are activated sequentially, increasing the levels of expression of C/EBPα, C/EBPε, and granulocyte colony-stimulating factor (G-CSF) receptor.

Green synthesis of copper oxide spindle like nanostructure using Hibiscus cannabinus flower extract for antibacterial and anticancer activity applications

In this study, CuO nanospindle synthesized using petal extract of Hibiscus cannabinus (H. cannabinus) was attempted to have better antibacterial activity against Gram-positive and Gram-negative bacteria. Cytotoxic activity was found to be 70 % against human acute myeloid leukemia HL60 cell line at 500 µg/ml. Morphological features of CuO was analyzed by scanning electron microscopy (SEM). Structural properties were analyzed by X-ray diffraction (XRD) pattern and the Fourier transform infrared (FTIR) spectrum of CuO provides additional evidence for the formation of monoclinic crystal structured CuO. Energy dispersive X-ray spectroscopy (EDAX) analysis exposed the pristine properties of CuO nanospindles.

Bacillamide F, Extracted from Marine Bacillus atrophaeus C89, Preliminary Effects on Leukemia Cell Lines.

Developing new treatments for leukemia is essential since current therapies often suffer from drug resistance and toxicity. Bacillamides are very promising, naturally occurring compounds with various bioactivities. In the present study, we investigated the use of bacillamide analogues, a new thiazole alkaloid bacillamide F that was isolated from marine Bacillus atrophaeus C89 associated with sponge Dysidea avara. The structure of the new compound bacillamide F with indolyl-thiazolyl-pyrrolidine ring was determined by high resolution mass spectrometry, secondary mass spectrometry, and nuclear magnetic resonance analyses. Intriguingly, bacillamide F is able to inhibit the proliferation of an acute myeloid leukemia cell line HL60 (IC50 (24 h) 21.82 µM), and an acute T-cell leukemia Jurkat (IC50 (24 h) 46.90 µM), rather than inhibit the proliferation of the acute histiocytic lymphoma U-937 cell line, human fetal lung fibroblast MRC-5 cell line, and some solid tumor cell lines (IC50 (24 h) &gt; 100 µM). The study provides a new indication of the pharmacological activity of natural product bacillamides.

Antiproliferative Activity and Apoptotic Potential of Curcumin on Human Acute Myeloid Leukemia Cell Line (HL-60)

Curcuma Longa or also known as turmeric is a prominent natural remedy in Asia that has been utilized to heal diseases for decades. It has been demonstrated to have substantial biological activities, including anticarcinogenic, antimutagenic, antioxidant, anti-inflammatory, anti-infectious, hypocholesterolemic, and chemopreventive properties. Curcumin is a therapeutic substance extracted from Curcuma Longa that is thought to have anti-cancer properties against a variety of cancer types. However, its anti-cancer potential on acute myeloid leukemia (AML) remains uncertain [1,2]. &#x0D; &#x0D; The objective of this intervention study was to examine the anti-proliferative and apoptotic effects of curcumin on the HL-60 cell line of acute myeloid leukemia. A stock solution of pure curcumin compound was obtained by dissolving it in dimethyl sulfide (DMSO). HL-60 cells were treated with six different concentrations which were 100, 50, 25, 12.5, 6.25, 3.125 µg/ml and incubated at three distinct incubation period (24, 48 and 72 hours). The in vitro cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and quantified using a microplate reader at 570 nm. Acridine orange (AO) and propidium iodide (PI) staining were employed to evaluate morphological changes. &#x0D; &#x0D; MTT assays results show that curcumin has a high cytotoxicity effect on HL-60 cells. The maximal half inhibitory concentration (IC50) value of curcumin was consistently decreased when the incubation time increased. The IC50 of curcumin on HL-60 cells were reported to be 13, 8, and 3.5 µg/ml at 24, 48 and 72 hours of incubation, respectively. There was a significantly different IC50 value (p&lt;0.05) of curcumin between the incubation periods (Figure 1). The morphological alteration was shown in AO/PI staining by the appearance of early apoptosis, late apoptosis, and necrotic cells.&#x0D; These findings illustrated that curcumin revealed an effective anti-cancer action on human acute myeloid leukemia HL-60 cell line. Further research is required to determine the mechanism of cell death in HL-60 cells treated with pure curcumin compound.&#x0D; &#x0D; In conclusion, the study revealed the role of putative targeted genes in the biological mechanism in gout pathogenesis has provides insight of the potential biomarkers in developing the personalized medicine better treatment for gout patient in ensuring better patient healthcare.

Anti-Leukemic Activity of Brassica-Derived Bioactive Compounds in HL-60 Myeloid Leukemia Cells.

Acute myeloid leukemia (AML) is a cancer of the myeloid blood cells mainly treated with chemotherapy for cancer remission, but this non-selective treatment also induces numerous side effects. Investigations with bioactive compounds from plant-derived foods against cancer have increased in the last years because there is an urgent need to search for new anti-leukemic agents possessing higher efficacy and selectivity for AML cells and fewer negative side effects. In this study, we analyzed the anti-leukemic activity of several phytochemicals that are representative of the major classes of compounds present in cruciferous foods (glucosinolates, isothiocyanates, hydroxycinnamic acids, flavonols, and anthocyanins) in the human acute myeloid leukemia cell line HL-60. Our results revealed that among the different Brassica-derived compounds assayed, sulforaphane (SFN) (an aliphatic isothiocyanate) showed the most potent anti-leukemic activity with an IC50 value of 6 µM in dose-response MTT assays after 48 h of treatment. On the other hand, chlorogenic acid (a hydroxycinnamic acid) and cyanidin-3-glucoside (an anthocyanin) also displayed anti-leukemic potential, with IC50 values of 7 µM and 17 µM after 48 h of incubation, respectively. Importantly, these compounds did not show significant cell toxicity in macrophages-like differentiated cells at 10 and 25 µM, indicating that their cytotoxic effects were specific to AML cancer cells. Finally, we found that these three compounds were able to induce the NRF2/KEAP1 signaling pathway in a dose-dependent manner, highlighting SFN as the most potent NRF2 activator. Overall, the present evidence shed light on the potential for using foods and ingredients rich in anticancer bioactive phytochemicals from Brassica spp.

Antitumor Effect of Glandora rosmarinifolia (Boraginaceae) Essential Oil through Inhibition of the Activity of the Topo II Enzyme in Acute Myeloid Leukemia.

It was previously shown that the antitumor and cytotoxic activity of the essential oil (EO) extracted from the aerial parts of Glandora rosmarinifolia appears to involve a pro-oxidant mechanism in hepatocellular carcinoma (HCC) and in triple-negative breast cancer (TNBC) cell lines. Its most abundant compound is a hydroxy-methyl-naphthoquinone isomer. Important pharmacological activities, such as antitumor, antibacterial, antifungal, antiviral and antiparasitic activities, are attributed to naphthoquinones, probably due to their pro-oxidant or electrophilic potential; for some naphthoquinones, a mechanism of action of topoisomerase inhibition has been reported, in which they appear to act both as catalytic inhibitors and as topoisomerase II poisons. Our aim was to evaluate the cytotoxic activity of the essential oil on an acute myeloid leukemia cell line HL-60 and on its multidrug-resistant (MDR) variant HL-60R and verify its ability to interfere with topoisomerase II activity. MTS assay showed that G. rosmarinifolia EO induced a decrease in tumor cell viability equivalent in the two cell lines; this antitumor effect could depend on the pro-oxidant activity of EO in both cell lines. Furthermore, G. rosmarinifolia EO reduced the activity of Topo II in the nuclear extracts of HL-60 and HL-60R cells, as inferred from the inability to convert the kinetoplast DNA into the decatenated form and then not inducing linear kDNA. Confirming this result, flow cytometric analysis proved that EO induced a G0-G1 phase arrest, with cell reduction in the S-phase. In addition, the combination of EO with etoposide showed a good potentiation effect in terms of cytotoxicity in both cell lines. Our results highlight the antitumor activity of EO in the HL-60 cell line and its MDR variant with a peculiar mechanism as a Topo II modulator. Unlike etoposide, EO does not cause stabilization of a covalent Topo II-DNA intermediate but acts as a catalytic inhibitor. These data make G. rosmarinifolia EO a potential anticancer drug candidate due to its cytotoxic action, which is not affected by multidrug resistance.

Effects of SIDT2 on the miR-25/NOX4/HuR axis and SIRT3 mRNA stability lead to ROS-mediated TNF-α expression in hydroquinone-treated leukemia cells.

Our previous studies indicated that the benzene metabolite hydroquinone (HQ) evokes the ROS/p38 MAPK/protein phosphatase 2A/tristetraprolin axis, leading to increased TNF-α expression in human acute myeloid leukemia cell lines U937 and HL-60. In this study, we aimed to identify the upstream pathway involved in ROS-mediated TNF-α expression. HQ treatment increased SIDT2 expression, which subsequently decreased miR-25 and SIRT3 expression in U937 cells. Notably, miR-25 downregulation promoted SIDT2 expression in HQ-treated U937 cells. SIDT2 induced lysosomal degradation of SIRT3 mRNA, but inhibited miR-25 expression through a lysosome-independent pathway. MiR-25 inhibition reduced NOX4 mRNA turnover, resulting in increased NOX4 protein levels. NOX4 induces mitochondrial ROS production and HuR downregulation. Restoration of HuR expression increased SIRT3 expression, suggesting that NOX4-mediated HuR downregulation promotes SIDT2-mediated degradation of SIRT3 mRNA. Inhibition of NOX4 or SIRT3 overexpression abolished HQ-induced ROS production, thereby abolishing TNF-α upregulation. Overall, these results indicate that SIDT2 regulates the miR-25/NOX4/HuR axis and SIRT3 mRNA destabilization, leading to ROS-mediated TNF-α upregulation in HQ-treated U937 cells. HQ-induced increase in TNF-α expression in HL-60 cells was also mediated through a similar pathway.

Effect of Competitive Antagonist of Transmembrane Glutamine Flux V-9302 on Apoptosis of Acute Myeloid Leukemia Cell Lines HL-60 and KG-1

To investigate the effect of V-9302 (an antagonist of transmembrane glutamine flux) on the proliferation and apoptosis of acute myeloid leukemia cells HL-60 and KG-1. HL-60 and KG-1 cells at logarithmic phase were treated by different concentrations of V-9302. CCK-8 assay was used to detect the proliferation of the cells. Annexin V-FITC / PI double staining flow cytometry was used to detect the apoptosis of HL-60 and KG-1 cells. The expressions of BAX, BCL-2 and Caspase3 were detected by RT-qPCR and Western blot. V-9302 could significantly inhibit the growth of HL-60 and KG-1 cells. The concentration of V-9302 at 10, 20 μmol/L could significantly promote the apoptosis of HL-60 and KG-1 cells(P<0.05). The results of apoptosis related gene detection showed that when V-9302 was applied to HL-60 and KG-1 cell lines at 10 and 20 μmol/L, the expression levels of Pro-apoptotic protein genes BAX and Caspase3 in HL-60 and KG-1 were significantly higher than those in control group (P<0.05), while the expression level of anti-apoptotic protein gene BCL-2 was significantly lower than that in the control group (P<0.05). The results of Western blot were basically consistent with that of RT-qPCR. Competitive antagonist of transmembrane glutamine flux V-9302 can significantly promote the apoptosis of acute myeloid leukemia cell lines HL-60 and KG-1.

Analysis of Peganum harmala, Melia azedarach and Morus alba extracts against six lethal human cancer cells and oxidative stress along with chemical characterization through advance Fourier Transform and Nuclear Magnetic Resonance spectroscopic methods towards green chemotherapeutic agents

Traditional medicines implicate consumption of plant crude extracts, which may consist of extensive phytochemical diversity. Overall, the most biologically active extract of Peganum harmala (seeds) exhibited significant cytotoxic activity on Artemia salina with LC50 value of 61.547 µg/mL, while P. harmala (roots) [LC50 = 124.229 µg/mL] and M. azedarach (fruits) [LC50 = 147.813 µg/mL] showed moderate cytotoxic potential. P. harmala (seeds) extract also showed the maximum antitumor potential with 52.278 µg/mL LC50. Branches of P. harmala and Morus alba were not active in both bioassays. These outcomes were further reinforced by the levels of phenolics and flavonoids checked against gallic acid and quercetin equivalents, respectively, by standard curves. Current study aims to isolate, structurally characterize and analyze the bioactive compound from plant extracts by using chromatographic and spectrophotometric techniques. Bioactivity guided isolation of extracts led to the isolation of PH-HM-16 from ethyl acetate fraction P. harmala seeds. Chemical structure of PH-HM-16 was elucidated by ESI-MS, 1H NMR, 13C NMR, HSQC and IR spectrum. The results demonstrated significant positive anticancer activities against six human cancer cell lines assessed through MTT cancer cell growth inhibition assay. PH-HM-16 was most effective against prostate cancer cell lines [IC50 = 17.63 µg/mL] followed by breast cancer cell line MCF7 [IC50 value of 41.81 µg/mL]. IC50 value of PH-HM-16 against human myeloid leukemia cell line HL-60 and human colorectal tumor cells HCT-116 was observed as 68.77 µg/mL and 71.54 µg/mL respectively. The IC 50 value of PH-HM-16 compound was not significant against human gastric cancer SGC-7901 (111.89 µg/mL) and human lung adenocarcinoma epithelial cell line A549 (176.04 µg/mL). Isolated bioactive metabolite PH-HM-16 possesses significant antitumor potential so this could be the first step to develop an effective anticancer agent. Hence, this compound represents a promising potential to be chemically standardized or developed into pharmaceuticals for the chemoprevention and/or the treatment of certain types of cancer, especially as adjuvant phytotherapeutics in conventional chemotherapy.

The Influence of Glutamic Pyruvate Transaminase 2 to Biological Characteristics of Acute Myeloid Leukemia Cell HL-60

To investigate the influence of GPT2（glutamic pyruvate transaminase 2）to biological characteristics of human acute myeloid leukemia cell line HL-60. The expression of GPT2 in hematological tumor and AML cell was detected. The lentvirus-mediated of short-hairpin RNA (shRNA) was constricted, and the knock-down efficiency of HL-60 in AML cell after infected by lentvirus-mediated was detected by Western blot and Q-PCR. CCK-8 assay and soft agar colony formation assay were used to detect the effect of GPT2 gene deletion to the cell proliferation potential. Fluorescence activated cell sorting(FACS) was used to analyze the effect of gene deletion to the cell cycle and Caspase 3/7 Activity Assay Kit was used to analyze the effect of GPT2 gene deletion to the cell apoptosis. GPT2 showed mRNA high expression in AML patients. CCK-8, soft agar assay, and Caspase 3/7 Activity Assay Kit results showed that compared with shCtrl group, the cells in shGPT2-1、shGPT2-2、shGPT2-3 group showed the slowing down on proliferation, decreasing on colony ability, and the apoptosis of the cells was increasing significantly. FACS showed that GPT2 gene was related to the cycle of HL-60 cell. GPT2 appears to involve the proliferation, cycle distribution and apoptosis of AML cell HL-60. The deletion of GPT gene can lead to the inhibitation of cells proliferation and increase apoptosis.

Effects and Mechanism of PARP Inhibitor Olaparib on the Expression of NKG2D Ligands in HL-60 Cells

To investigate the regulatory effects of Olaparib on natural killer cell activating receptor (NKG2D) ligands expression on human acute myeloid leukemia (AML) cell line HL-60, and to explore the molecular mechanism of Olaparib on HL-60 cells. After HL-60 cells in logarithmic growth phase were treated with Olaparib at different concentrations for different times (24, 48 h), the expression of NKG2D ligand on the surface of HL-60 cells was detected by flow cytometry. Western blot was used to dectect the expression of ERK expression in HL-60 cells. The killing effect of NK cells to HL-60 cells was detected by CFSE/PI method. 10 μmol/L Olaparib could upregulate the expression of NKG2D ligand on the surface of HL-60 cell at 24 and 48 hours, while 5 μmol/L Olaparib could induce up-regulation of the expression of ULBP-2 and ULBP-3 at 48 hours. Western blot analysis showed that ERK phosphorylation of HL-60 cells was enhanced after treating with Olaparib. The killing effect of NK cells to HL-60 cells could be enhanced by Olaparib, however, ERK inhibitor could suppress the killing effect of NK cells to HL-60 cells. Olaparib can upregulate NKG2D ligands expression on the surface of HL-60 cells and enhance the cytotoxicity of NK cell to HL-60 cells. The mechanism may be related to Olaparib promoting ERK phosphorylation expression.

An Evaluation of the Activity of Histidine-Rich Glycoprotein on Differentiated Neutrophil-Like Cells from Human Cell Lines.

Histidine-rich glycoprotein (HRG) treatment ameliorated the survival rate of septic mice by suppressing excess immunothrombus formation. Although such findings suggested that HRG may be one of the most useful drugs for sepsis, obtaining a stable experimental system to standardize the HRG drug product is difficult to achieve using neutrophils isolated from volunteers. This is due to the short survival time and individual differences of human neutrophils. In the present study, we determined whether the differentiated neutrophil-like cell lines exhibited similar responses to HRG compared with human purified neutrophils. All-trans retinoic acid (ATRA) was employed to induce the differentiation of the human myeloid leukemia cell lines HL-60 and NB-4. Thereafter, the cells were treated with Hank's balanced salt solution, human serum albumin, or HRG. The effects of HRG on these cells were evaluated according to cell shape, microcapillary passage, reactive oxygen species (ROS) production, neutrophil extracellular traps (NETs) formation, the expression of activated CD11b, and cell viability. HRG maintained the round shape of differentiated neutrophil-like cells, decreased the time required by cells to pass through the microcapillaries, and inhibited ROS production, NETs formation, and the expression of activated CD11b on the cell surface. Moreover, the cells could survive longer in the presence of HRG than the control. The ATRA-induced differentiated cell lines could be used as alternatives to neutrophils to investigate the effects of HRG on neutrophils. This method can thus be used as an essential standardization test in pharmaceutical development. SIGNIFICANCE STATEMENT: Human neutrophils exhibit varying responses to histidine-rich glycoprotein (HRG); however, all-trans retinoic acid-induced differentiated neutrophil-like cell lines can be used as reliably proxies to investigate the effects of HRG on neutrophils. Additionally, these cell lines can be employed in the development of therapies for the treatment of sepsis.

Axolotl Ambystoma mexicanum extract induces cell cycle arrest and differentiation in human acute myeloid leukemia HL-60 cells.

Acute myeloid leukemia is the most common form of acute leukemia in adults, constituting about 80% of cases. Although remarkable progress has been made in the therapeutic scenario for patients with acute myeloid leukemia, research and development of new and effective anticancer agents to improve patient outcome and minimize toxicity is needed. In this study, the antitumor activity of axolotl (AXO) Ambystoma mexicanum crude extract was assessed in vitro on the human acute myeloid leukemia HL-60 cell line. The anticancer activity was evaluated in terms of ability to influence proliferative activity, cell viability, cell cycle arrest, and differentiation. Moreover, gene expression analysis was performed to evaluate the genes involved in the regulation of these processes. The AXO crude extract exhibited antiproliferative but not cytotoxic activities on HL-60 cells, with cell cycle arrest in the G0/G1 phase. Furthermore, the AXO-treated HL-60 cells showed an increase in both the percentage of nitroblue tetrazolium positive cells and the expression of CD11b, whereas the proportion of CD14-positive cells did not change, suggesting that extract is able to induce differentiation toward the granulocytic lineage. Finally, the treatment with AXO extract caused upregulation of CEBPA, CEBPB, CEBPE, SPI1, CDKN1A, and CDKN2C, and downregulation of c-MYC. Our data clearly show the potential anticancer activity of Ambystoma mexicanum on HL-60 cells and suggest that it could help develop promising therapeutic agents for the treatment of acute myeloid leukemia.

A New Hybrid δ-Lactone Induces Apoptosis and Potentiates Anticancer Activity of Taxol in HL-60 Human Leukemia Cells.

In the search for new drug candidates, researchers turn to natural substances isolated from plants which may be either used directly or may serve as a source for chemical modifications. An interesting strategy in the design of novel anticancer agents is based on the conjugation of two or more biologically active structural motifs into one hybrid compound. In this study, we investigated the anticancer potential of 4-benzyl-5,7-dimethoxy-4-methyl-3-methylidene-3,4-dihydro-2H-chroman-2-one (DL-247), a new hybrid molecule combining a chroman-2-one skeleton with an exo-methylidene bond conjugated with a carbonyl group, in human myeloid leukemia HL-60 cell line. The cytotoxicity of the new compound was tested using MTT assay. The effect of DL-247 on cell proliferation and apoptosis induction were studied by flow cytometry, fluorometric assay and ELISA analysis. DL-247 displayed high cytotoxic activity (IC50 = 1.15 µM, after 24 h incubation), significantly inhibited cell proliferation and induced apoptosis by both, the intrinsic and extrinsic pathways. A combination of DL-247 with taxol exhibited a strong synergistic effect on DNA damage generation, apoptosis induction and inhibition of cell growth.

Molecular mechanisms of apoptosis induced by a novel synthetic quinolinone derivative in HL-60 human leukemia cells

The mortality rates for acute myeloid leukemia are very high, necessitating the search for novel chemotherapeutic candidates. Herein, we investigated the anticancer potential of a new synthetic compound, 2-ethyl-3-methyliden-1-tosyl-2,3-dihydroquinolin-4-(1H)-one (AJ-374) against myeloid leukemia HL-60 cell line. This analog was selected from the small library of synthetic dihydroquinolinones on the basis of its strong antiproliferative activity against HL-60 cells and 30-fold lower cytotoxicity towards healthy HUVEC cells. AJ-374 promoted the arrest of the cells in the subG0/G1 phase of the cell cycle in the first 24 h. Treatment of HL-60 cells with AJ-374 caused an increase in annexin-V positive cells, activation of caspase-8, -9 and -3, dissipation of the mitochondrial membrane potential and enhancement of FAS protein level. Apoptosis induction triggered by this quinolinone was blocked by the pre-treatment of the cells with caspase-8, -9 and -3 inhibitors. The obtained results indicated that AJ-374-induced apoptosis was executed by both, the extrinsic and intrinsic pathways. The cytotoxic activity of AJ-374 was also associated with down-regulation of the mitogen-activated protein kinase (MAPK) pathway and was independent of reactive oxygen species generation. Taken together, these results suggest that AJ-374 exerts a potent anticancer effect on leukemia cells, with a wide safety margin, which makes this analog an attractive drug candidate for further testing.

Amide and ester derivatives of chlorido[4-carboxy-1,2-disalicylideneaminobenzene]iron(iii) as necroptosis and ferroptosis inducers.

In continuation of the structure-activity study about 4-substituted chlorido[N,N'-disalicylidene-1,2-phenylenediamine]iron(iii) complexes as necroptosis and ferroptosis inducers, we introduced a 4-COOH group at the 1,2-phenylenediamine moiety of the lead ([Fe(iii)salopheneCl]) and derived the resulting complex 15 to the respective ethyl, propyl, or butyl amides (16-18) and esters (19-21). The compounds 16-21 exerted concentration-dependent antiproliferative and antimetabolic effects against HL-60 cells. The esters were more active than the analogous amides. Elongation of the alkyl chain enhanced the activity of the amides, while that of the esters decreased. The complexes 16-21 induced necroptosis and/or ferroptosis but not apoptosis. Studies on protein binding and uptake into HL-60 cells indicated that the complexes mainly accumulated by passive transport. The high binding tendency of all complexes to apo-Transferrin, however, points to participation of a carrier-mediated transport into the cells, too.

Effect of SALL4 on radiosensitivity of leukemia cell line HL-60

Objective To evaluate the effect of down-regulating SALL4 on the radiosensitivity of leukemia cells, aiming to provide new ideas for improving radiosensitivity of leukemia patients. Methods Human acute myeloid leukemia cell line HL-60 infected with shRNA SALL4 and shRNA control lentivirus was classified into the Lv-shSALL4 group and Lv-shNC group. The levels of SALL4 mRNA and protein in cells were detected by RT-PCR and Western blot. The infected cells treated with 8 Gy dose irradiation were assigned into the Lv-shSALL4+ radiation and Lv-shNC+ radiation groups. The cell apoptosis was detected by flow cytometry. The levels of cleaved Caspase-3, cleaved Caspase-9 and Bax proteins in cells were determined by Western blot. The cells in the Lv-shSALL4 and Lv-shNC groups were exposed to 0, 2, 4, 6 and 8 Gy irradiation. The radiosensitivity ratio was determined by cell clone test. Results The level of SALL4 in the Lv-shSALL4 group was significantly lower than that in the Lv-shNC group (P<0.05). The cell apoptosis rate was significantly increased, the levels of cleaved Caspase-3, cleaved Caspase-9 and Bax proteins were remarkably up-regulated in cells compared with those in the Lv-shNC group (all P<0.05). The cell proliferation ability in the Lv-shSALL4+ radiation was significantly reduced, the cell apoptosis rate was considerably increased, the levels of cleaved Caspase-3, cleaved Caspase-9 and Bax proteins were significantly up-regulated compared with those in the Lv-shSALL4 and Lv-shNC+ radiation groups (all P<0.05). The cell radiosensitization ratio in the Lv-shSALL4 group was 1.323. Conclusion Down-regulating SALL4 can increase the radiosensitivity of leukemic cells, inhibit the cell proliferation and induce the apoptosis of leukemic cells. Key words: SALL4 gene; HL-60 cell line; Radiosensitivity