Human Leukemia Cell Line HL-60 Research Articles

Cytochalasins D1 and C1, unique cytochalasans from endophytic fungus Xylaria cf. curta

Cytochalasins D1 (1) and C1 (2) were isolated from the liquid fermentation of fungus Xylaria cf. curta. Their structures and absolute configurations were determined by comprehensive experimental spectroscopic methods as well as ECD and GIAO 13C NMR calculation. They possess a unique eleven-membered macrocycle with an oxygen bridge. Cytochalasins D1 and C1 showed moderate cytotoxicity against human leukemia cell lines HL-60 with IC50 value of 12.7 and 22.3 μM, respectively.

Esterified Derivatives of Panaxadiol and Their Inhibitory Effect on HL‐60, THP‐1, and PC‐3 Cell Lines

Panaxadiol is a dammarane-type ginsenoside having high ginseng content. The 3-hydroxy group of panaxadiol (PD) was modified by fatty acids and diacids. The modified panax glycol had enhanced anticancer activity. Twelve PD derivatives were evaluated and purified by chemical synthesis, column chromatography, co-synthesis, and identification. The human leukemia cells THP-1, HL-60, and human prostate cancer cell lines PC-3 were evaluated; PD derivatives were tested and evaluated in vitro by MTT assay. The results showed that the antitumor activities of some derivatives on three tumor cell lines were better than those of PD.

Preliminary results indicate resveratrol affects proliferation and apoptosis of leukemia cells by regulating PTEN/PI3K/AKT pathway.

PTEN-PI3K/AKT signaling pathway is widely involved in the regulation of cell proliferation, cell cycle, apoptosis, and invasion. Resveratrol (Resv) is a natural botanical ingredient involved in several biological activities. It is still unclear in terms of whether Resv may exert anti-leukemia effects by regulating the PTEN-PI3K/AKT pathway. This study investigated the effect of Resv on leukemia cell proliferation and apoptosis by regulating PTEN-PI3K/AKT pathway. Human normal peripheral blood PBMC cells, and human acute promyelocytic leukemia (APL) cell line NB-4 and HL-60 cells were cultured in vitro. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect Phosphatase and tensin homolog (PTEN) mRNA expression. Western blot was adopted to test PTEN protein expression. HL-60 and NB-4 cells were treated with 0, 5, 10, and 20 μM Resv, respectively. Cell proliferation was analyzed by cell counting kit8 (CCK-8) assay. The level of caspase-3 was measured by Western blot. HL-60 cells were divided into control group, 20 μM Resv treatment group, and Resv+PTEN inhibitor SF1670 group. Cell apoptosis was determined by flow cytometry. Cell proliferation was assessed by EdU staining. Compared with peripheral blood mononuclear cell (PBMC), PTEN mRNA and protein levels were significantly decreased in NB-4 and HL-60 cells. Resv significantly inhibited the proliferation activity in HL-60 and NB-4 cells, and increased the activity of caspase-3. Resv treatment up-regulated the expression of PTEN and reduced the expression of p-AKT protein in HL-60 cells. However, Resv treatment markedly suppressed the proliferation of HL-60 and induced apoptosis. SF1670 treatment in the presence of Resv significantly antagonized the down-regulation of p-AKT protein expression induced by Resv, resulting in decreased apoptosis and enhanced cell proliferation. Resv can up-regulate PTEN expression and inhibit the activity of PI3K/AKT pathway to play an anti-leukemia effect through suppressing cell proliferation and inducing apoptosis.

USP39 regulates the cell cycle, survival, and growth of human leukemia cells.

Ubiquitin-specific peptidase 39 (USP39) is one member of the cysteine proteases of the USP family, which represents the largest group of DeUbiquitinases with more than 50 members in humans. The roles of USP39 in human cancer have been widely investigated. However, the roles of USP39 in human leukemia and the underlying mechanism remain unknown. Here we reported the function of USP39 in human leukemia. We observed that the expression of USP39 was up-regulated in human leukemia cells and the high expression of USP39 was correlated with poor survival of the patients with leukemia. Lentivirus-mediated knockdown of USP39 repressed the proliferation and colony formation of human leukemia cell lines HL-60 and Jurkat cells. Mechanism study showed that USP39 knockdown induced the arrest of cell cycle and apoptosis of leukemia cells. In addition, our microarray and bioinformatic analysis demonstrated that USP39 regulated diverse cellular signaling pathways that were involved in tumor biology, and several pivotal genes (IRF1, Caspase 8, and SP1) have been validated by quantitative real-time polymerase chain reaction. Knockdown or IRF1 partially restored the proliferation rate of leukemia cells with USP39 knockdown. Taken together, our findings implicate that USP39 promotes the development of human leukemia by regulating cell cycle, survival, and proliferation of the cells.

Anticancer potential of metabolic compounds from marine actinomycetes isolated from Lagos Lagoon sediment

Thirty-two actinomycetes strains were isolated from sediment samples from 12 different sites at Lagos Lagoon and identified using standard physiological and biochemical procedures as well as 16S rDNA gene sequence analysis. Secondary metabolites were extracted from the strains and their anticancer activity on the K562 (Human acute myelocytic leukemia), HeLa (cervical carcinoma), AGS (Human gastric), MCF-7 (breast adenocarcinoma) and HL-60 (Human acute promyelocytic leukemia) cell lines was determined. The metabolic extracts exhibited cytotoxicity with IC50 values ranging from 0.030 mg/mL to 4.4 mg/mL. The Streptomyces bingchenggensis ULS14 extract was cytotoxic against all the cell lines tested. The bioactivity-guided extraction and purification of the metabolic extracts from this strain yielded two purified anticancer compounds: ULDF4 and ULDF5. The structures of the extracted compounds were determined using spectroscopic analyses, including electrospray ionization mass spectrophotometer and nuclear magnetic resonance (1 Dimensional and 2 Dimensional), and were shown to be structurally similar to staurosporine and kigamicin. The IC50 of ULDF4 and ULDF5 against the HeLa cell line was 0.034 μg/mL and 0.075 μg/mL, respectively. This study is the first to reveal the anticancer potential of actinomycetes from Lagos Lagoon, which could be exploited for therapeutic purposes.

Development of an Opsonophagocytic Killing Assay Using HL-60 Cells for Detection of Functional Antibodies against Streptococcus pyogenes.

The clinical development of group A streptococcal (GAS) vaccines will require the implementation of a standardized, high-throughput assay to measure the activity of functional opsonic antibodies in vaccine recipients. In the present study, we adapted and modified the HL-60-based protocol that was developed for the detection of opsonic antibodies against Streptococcus pneumoniae for use with multiple M types of GAS. Modifications of the assay conditions permitted the evaluation of 21 different M types of GAS in the assay. The specificity of the antibody-mediated opsonization was demonstrated by inhibition with homologous, but not heterologous, M proteins. Maximum rates of opsonophagocytic killing (OPK) of 14 different M types promoted by rabbit antiserum against the 30-valent M protein-based vaccine were comparable in whole-blood and HL-60 assays. Data are also presented showing OPK serum titers (opsonic index) of naturally acquired human antibodies present in IVIG [intravenous immune globulin (human)]. Results of the HL-60 assay performed on different days using 21 different M types of GAS and IVIG as the antibody source were significantly concordant. This report indicates that the OPK assay conditions may be optimized for the measurement of opsonic antibodies against a number of epidemiologically important M types of GAS and, once standardized, should facilitate the clinical development of effective vaccines to prevent these infections.IMPORTANCE Measuring functional opsonic antibodies against group A streptococci is an important component of the clinical development path for effective vaccines. Prior studies have used an assay developed over 60 years ago that relied on whole human blood as the source of phagocytes and complement, both of which are critical components of antibody-mediated killing assays. In this study, we adapted an assay that uses the HL-60 human promyelocytic leukemia cell line as phagocytic cells and baby rabbit serum as a source of complement for detection of opsonic antibodies against group A streptococci. On the basis of some of the known biological characteristics of the bacteria, we modified the assay conditions to support the evaluation of 21 epidemiologically important M types and demonstrated the utility and reproducibility of the assay for measurement of functional opsonic antibody levels.

RA-XXV and RA-XXVI, Bicyclic Hexapeptides from Rubia cordifolia L.: Structure, Synthesis, and Conformation.

Two RA-series bicyclic hexapeptides, RA-XXV (4) and RA-XXVI (5), which have no N-methyl group at Tyr-5, were isolated from the roots of Rubia cordifolia L. Their amino acid compositions and sequences were determined by interpretation of MS, and 1D and 2D NMR data and their relative structures were elucidated by XRD analysis of 4 and RA-XXVI acetate (6). The absolute stereochemistry of 4 was established by the total synthesis of 4, and that of 5, by the chemical correlation with 4. Peptides 4 and 5 exhibited cytotoxicity toward human promyelocytic leukemia HL-60 (IC50 =0.062 and 0.066 μm, respectively) and human colonic carcinoma HCT-116 (IC50 =0.028 and 0.051 μm, respectively) cell lines. Analysis of the conformational structures of 4 and 6 in the crystalline state and those of 4 and 5 in solution revealed that the N-methyl group at Tyr-5 functions to make this series of peptides preferentially adopt the active conformation.

Deacetylase activity-independent transcriptional activation by HDAC2 during TPA-induced HL-60 cell differentiation.

The human myeloid leukemia cell line HL-60 differentiate into monocytes following treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA). However, the mechanism underlying the differentiation of these cells in response to TPA has not been fully elucidated. In this study, we performed ChIP-seq profiling of RNA Pol II, HDAC2, Acetyl H3 (AcH3), and H3K27me3 and analyzed differential chromatin state changes during TPA-induced differentiation of HL-60 cells. We focused on atypically active genes, which showed enhanced H3 acetylation despite increased HDAC2 recruitment. We found that HDAC2 positively regulates the expression of these genes in a histone deacetylase activity-independent manner. HDAC2 interacted with and recruited paired box 5 (PAX5) to the promoters of the target genes and regulated HL-60 cell differentiation by PAX5-mediated gene activation. Taken together, these data elucidated the specific-chromatin status during HL-60 cell differentiation following TPA exposure and suggested that HDAC2 can activate transcription of certain genes through interactions with PAX5 in a deacetylase activity-independent pathway.

Experimental study on bi-chimeric antigen receptors modified T lymphocytes targeting on acute myeloid leukemia

Objective To study the cytotoxicity of bi-chimeric antigen receptors modified T lymphocytes (BiCAR-T) on the human acute myeloid leukemia (AML) cell line HL60 in vitro and the anti-tumor effects of BiCAR-T on the NOD SCID mouse model of AML in vivo. Methods The BiCAR-T were prepared and the expression of chimeric antigen receptor (CAR) of prepared BiCAR-T was analyzed by flow cytometry. In vitro study was divided into two groups: the experiment group (BiCAR-T) and the control group (T lymphocyte). The killing rate of BiCAR-T in vitro on HL60 cells was determined by CCK8 assay and the level of interferon-γ (IFN-γ) secreted from BiCAR-T co-culturing with HL60 cells for 48 hours was detected by enzyme linked immunosorbent assay (ELISA) at different effect/target ratios (5∶1, 10∶1, 20∶1). The NOD SCID mice AML model was established by the injection of HL60 cells through tail vein and used to assess the anti-tumor effects in vivo. The mice were randomly divided into three groups according to the random number table: the blank control group receiving 0.9% NaCl 0.2 ml through tail vein, the model group and the treatment group receiving 1×107 HL60 cells in 0.2 ml phosphate buffer saline (PBS). After 20 days, the treatment group was injected with 2×107 BiCAR-T in 0.2 ml PBS 3 times a week for 2 weeks, while the other two groups received 0.9% NaCl 0.2 ml. The pathological changes in the mice livers and spleens were observed after 2 weeks of treatment. Results The CAR expression rates of BiCAR-T were more than 50.00%. In vitro experiments proved that the killing rates of BiCAR-T in the experimental group and T lymphocytes in the control group on HL60 cells were (25.43±1.32)% vs. (16.18±0.75)%, (50.33±3.11)% vs. (25.47±1.27)%, and (85.89±3.96)% vs. (49.45±2.77)% at different effect/target ratios (5∶1, 10∶1, 20∶1). The killing efficiency of BiCAR-T and T lymphocytes on HL60 cells was significantly different (F=404.17, P<0.001); the killing efficiency of BiCAR-T and T lymphocytes on HL60 cells was significantly different at different effect/target ratios (F=548.09, P<0.001); and the killing efficiency on HL60 cells in the experimental group (BiCAR-T) was significantly higher than that in the control group (T lymphocytes) at different effect/target ratios (F=45.36, P<0.001). The IFN-γ levels secreted from BiCAR-T in the experiment group and T lymphocytes in the control group co-culturing with HL60 cells after 48 h were (435.65±20.44)pg/ml vs. (356.75±19.87)pg/ml, (1 639.98±95.75)pg/ml vs. (1 109.37±80.98)pg/ml, and (3 467.43±187.54)pg/ml vs. (2 245.52±112.66)pg/ml. The IFN-γ level in the experiment group (BiCAR-T) and the control group (T lymphocytes) was significantly different (F=156.24, P<0.001); the IFN-γ level was significantly different at different effect/target ratios (F=857.67, P<0.001); the IFN-γ level in the experimental group (BiCAR-T) was significantly higher than that in the control group (T lymphocytes) at different effect/target ratios of 5∶1, 10∶1, 20∶1, respectively (F=46.31, P<0.001). The result of hematoxylineosin staining (HE) staining showed that leukocyte infiltration in the treatment group was significantly decreased compared with the model group. Conclusion The experimental results showed that BiCAR-T is a kind of efficient targeted immunocyte modified by gene engineering, and it can significantly inhibit leukocyte infiltration of AML in vivo and in vitro. Key words: Leukemia, myeloid, acute; T-lymphocytes; Chimeric antigen receptor

Silencing of TIM-3 Expression by miR-326 Affects Apoptosis and Proliferation of Human HL-60 Leukemia Cell Line

Silencing of TIM-3 Expression by miR-326 Affects Apoptosis and Proliferation of Human HL-60 Leukemia Cell Line

A rapid and sensitive LC–MS/MS method for quantitative analysis of cardiolipin (18:2)4 in human leukocytes and mouse skeletal muscles

A rapid and sensitive LC–MS/MS method has been developed for quantitative analysis of cardiolipin (18:2)4 or CL (18:2)4 in human leukocytes and mouse mitochondria. The structural analog CL (14:0)4 was used as the internal standard. Both CL (18:2)4 and the IS were extracted using a modified Folch method, and separated on a Waters XBridge® BEH C18 XP column using a mobile phase of 0.1% ammonium hydroxide in acetonitrile/water (90:10, v/v) pumped at a flow rate of 0.4 mL/min. Quantitation was achieved by negative ESI-MS/MS in MRM mode. The total run time was 2.00 min with retention times of 0.74 min for the IS and 0.84 min for CL (18:2)4, respectively. The method was validated according to the US-FDA guidance for bioanalytical method validation using human leukemia and lymphoma cell lines, which had a calibration range of 0.120–60.2 nM with a correlation coefficient >0.999. The intra- and inter-assay accuracy and precision were ≤±5% and ≤8%. The IS normalized matrix factors of CL (18:2)4 and the IS normalized recoveries of CL (18:2)4 ranged 0.92–1.04, and 95–101%, respectively. The stability studies showed that CL (18:2)4 was stable under various test conditions. The developed method was successfully applied to the measurement of CL (18:2)4 in various biological samples including K562 and HL-60 human leukemia cell lines, U937 human lymphoma cell line, white blood cells from patients of Alzheimer’s disease and normal cognitive controls (NCCs), and mitochondria from mouse skeletal muscles. It may be useful for preclinical and clinical studies of this compound.

Structure-Activity Relationships of Nitro-Substituted Aroylhydrazone Iron Chelators with Antioxidant and Antiproliferative Activities.

Aroylhydrazone iron chelators such as salicylaldehyde isonicotinoyl hydrazone (SIH) protect various cells against oxidative injury and display antineoplastic activities. Previous studies have shown that a nitro-substituted hydrazone, namely, NHAPI, displayed markedly improved plasma stability, selective antitumor activity, and moderate antioxidant properties. In this study, we prepared four series of novel NHAPI derivatives and explored their iron chelation activities, anti- or pro-oxidant effects, protection against model oxidative injury in the H9c2 cell line derived from rat embryonic cardiac myoblasts, cytotoxicities to the corresponding noncancerous H9c2 cells, and antiproliferative activities against the MCF-7 human breast adenocarcinoma and HL-60 human promyelocytic leukemia cell lines. Nitro substitution had both negative and positive effects on the examined properties, and we identified new structure-activity relationships. Naphthyl and biphenyl derivatives showed selective antiproliferative action, particularly in the breast adenocarcinoma MCF-7 cell line, where they exceeded the selectivity of the parent compound NHAPI. Of particular interest is a compound prepared from 2-hydroxy-5-methyl-3-nitroacetophenone and biphenyl-4-carbohydrazide, which protected cardiomyoblasts against oxidative injury at 1.8 ± 1.2 μM with 24-fold higher selectivity than SIH. These compounds will serve as leads for further structural optimization and mechanistic studies.

Long noncoding RNA UCA1 promotes cell proliferation, migration and invasion of human leukemia cells via sponging miR-126.

Acute myeloid leukemia (AML) is a bone marrow malignancy. Long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) plays an important role in several cancers. However, the role of lncRNA UCA1 in AML remained unclear. LncRNA UCA1 expressions in different cell lines were determined by RT-PCR. In human myelogenous leukemia (ML) cell lines K562 and HL60, effects of lncRNA UCA1 knockdown on cell viability, migration, invasion, and apoptosis were assessed, respectively. Binding effects between lncRNA UCA1 and microRNA (miR)-126, and between miR-126 and RAC1 3'UTR were detected by RT-PCR and luciferase activity assay. Involvements of miR-126 and RAC1 in lncRNA UCA1-mediated cell bioactivities were assessed. We found that lncRNA UCA1 was upregulated in ML cell lines. Knockdown of lncRNA UCA1 inhibited cell viability, migration, invasion, and prompted apoptosis of ML cells in vitro. LncRNA UCA1 could bind with miR-126 and downregulate miR-126 expression. Simultaneously, the anti-growth and anti-metastasis actions of lncRNA UCA1 knockdown on ML cells were reversed by miR-126 suppression. RAC1 was a target gene of miR-126, and the anti-ML actions of miR-126 were abolished by RAC1 overexpression. Moreover, PI3K/AKT and JAK/STAT signaling pathways were blocked by miR-126 overexpression while were activated by RAC1 overexpression. Taken together, this study elucidates a novel UCA1-miR-126-RAC1 regulatory network in ML cells, which may provide the feasibility for use lncRNA-based therapy in AML treatment.

The Effect of Bone Marrow Mesenchymal Stem Cells on the Granulocytic Differentiation of HL-60 Cells.

Objective:Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a variety of cell types. They control the process of hematopoiesis by secreting regulatory cytokines and growth factors and by the expression of important cell adhesion molecules for cell-to-cell interactions. This investigation was intended to examine the effect of bone marrow (BM)-derived MSCs on the differentiation of HL-60 cells according to morphological evaluation, flow cytometry analysis, and gene expression profile.Materials and Methods:The BM-MSCs were cultured in Dulbecco’s modified Eagle’s medium supplemented with 10% fetal bovine serum (FBS). After the third passage, the BM-MSCs were irradiated at 30 Gy. To compare how the HL-60 cells differentiated in groups treated differently, HL-60 cells were cultured in RPMI-1640 and supplemented with 10% FBS. The HL-60 cells were seeded into six-well culture plates and treated with all-trans-retinoic acid (ATRA), BM-MSCs, or BM-MSCs in combination with ATRA, while one well remained as untreated HL-60 cells. The expression levels of the granulocyte subset-specific genes in the HL-60 cells were assayed by real-time polymerase chain reaction.Results:Our results revealed that BM-MSCs support the granulocytic differentiation of the human promyelocytic leukemia cell line HL-60.Conclusion:Based on the results of this study, we concluded that BM-MSCs may be an effective resource in reducing or even preventing ATRA’s side effects and may promote differentiation for short medication periods. Though BM-MSCs are effective resources, more complementary studies are necessary to improve this differentiation mechanism in clinical cases.

Rapid structure prediction by HPLC-ESI-MSn of twenty-five polyoxypregnane tetraglycosides from Dregea sinensis with NMR confirmation of eight structures

Dregea sinensis Hemsl is an important herbal medicine in the Dai nationality of China. Its prominent clinical application has generated interest in the polyoxypregnane glycosides of the plant. This paper describes an extension of previous research on the polyoxypregnane di- and triglycosides of D. sinensis, aiming at identifying related tetraglycosides. On the basis of HPLC-ESI-MSn analysis in positive mode, twenty-five previously undescribed polyoxypregnane tetraglycosides were characterized (regarding molecular masses and fragmentation in MSn) from an ethyl acetate fraction that was not previously investigated. Guided by MSn fragmentation and known structures of related di- and triglycosides from D. sinensis, tentative structures were predicted from the MS data. In order to test the predictions, eight of the glycosides were isolated and their structures were elucidated by 1D and 2D NMR methods, confirming the tentative predictions. Finally, the cytotoxicity of the isolates was evaluated on several human cell lines with little effect in general, even though slight inhibitory effects of four polyoxypregnane glycosides were detected at 10 μM against the human leukemia cell line HL-60.

Deoxynivalenol and Nivalenol Toxicities in Cultured Cells: a Review of Comparative Studies.

The in vitro studies of the toxicities of trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) including cell proliferation, cytokine secretion, and the involvement of heat shock protein 90 (Hsp90) in their toxicities were reviewed. Trichothecene mycotoxins are extremely toxic to leukocytes and leukopenia is one of the leading signs of trichothecene toxicosis, implying that trichothecenes hinder cell proliferation. Both toxins retarded proliferation of all four cell lines tested. NIV was more potent than DON in human promyelocytic leukemia cell line HL60, human lymphoblastic leukemia cell line MOLT-4, and rat aortic myoblast cell line A-10. In contrast, both toxins exhibited almost the same potencies in human hepatoblastoma cell line HepG2. While exposure to 0.3 μg/mL DON greatly induced the secretion of anti-hematopoietic cytokines CCL3 and CCL4, treatment with NIV decreased the secretion of these cytokines in HL60 cells, indicating that the toxicity mechanisms of these mycotoxins differ. Because molecular chaperone Hsp90 occupies a pivotal position in a wide range of pathological processes, the effects of an Hsp90-specific inhibitor radicicol on cytokine secretions were investigated. Radicicol counteracted the effect of DON on cytokine secretion, indicating that Hsp90 plays a crucial role in DON-induced cytokine secretion in HL60 cells. Conversely, the results of co-treatment with NIV and radicicol indicate that radicicol does not mitigate the effect of NIV. Regarding CCL3 and CCL4 secretions, DON and NIV have Hsp90-related and -unrelated mechanisms of toxicities, respectively. Taken together the results suggest that, although these toxins share similar chemical structure, there are differences in their toxic mechanisms.

Design, synthesis, in vitro antiproliferative activity and apoptosis-inducing studies of 1-(3′,4′,5′-trimethoxyphenyl)-3-(2′-alkoxycarbonylindolyl)-2-propen-1-one derivatives obtained by a molecular hybridisation approach

Inhibition of microtubule function using tubulin targeting agents has received growing attention in the last several decades. The indole scaffold has been recognized as an important scaffold in the design of novel compounds acting as antimitotic agents. Indole-based chalcones, in which one of the aryl rings was replaced by an indole, have been explored in the last few years for their anticancer potential in different cancer cell lines. Eighteen novel (3′,4′,5′-trimethoxyphenyl)-indolyl-propenone derivatives with general structure 9 were synthesized and evaluated for their antiproliferative activity against a panel of four different human cancer cell lines. The highest IC50 values were obtained against the human promyelocytic leukemia HL-60 cell line. This series of chalcone derivatives was characterized by the presence of a 2-alkoxycarbonyl indole ring as the second aryl system attached at the carbonyl of the 3-position of the 1-(3′,4′,5′-trimethoxyphenyl)-2-propen-1-one framework. The structure–activity relationship (SAR) of the indole-based chalcone derivatives was investigated by varying the position of the methoxy group, by the introduction of different substituents (hydrogen, methyl, ethyl or benzyl) at the N-1 position and by the activity differences between methoxycarbonyl and ethoxycarbonyl moieties at the 2-position of the indole nucleus. The antiproliferative activity data of the novel synthesized compounds revealed that generally N-substituted indole analogues exhibited considerably reduced potency as compared with their parent N-unsubstituted counterparts, demonstrating that the presence of a hydrogen on the indole nitrogen plays a decisive role in increasing antiproliferative activity. The results also revealed that the position of the methoxy group on the indole ring is a critical determinant of biological activity. Among the synthesized derivatives, compound 9e, containing the 2-methoxycarbonyl-6-methoxy-N-1H-indole moiety exhibited the highest antiproliferative activity, with IC50 values of 0.37, 0.16 and 0.17 μM against HeLa, HT29 and MCF-7 cancer cell lines, respectively, and with considerably lower activity against HL-60 cells (IC50: 18 μM). This derivative also displayed cytotoxic properties (IC50 values ∼1 μM) in the human myeloid leukemia U-937 cell line overexpressing human Bcl-2 (U-937/Bcl-2) via cell cycle progression arrest at the G2-M phase and induction of apoptosis. The results obtained also demonstrated that the antiproliferative activity of this molecule is related to inhibition of tubulin polymerisation. The presence of a methoxy group at the C5- or C6-position of the indole nucleus, as well as the absence of substituents at the N-1-indole position, contributed to the optimal activity of the indole-propenone-3′,4′,5′-trimethoxyphenyl scaffold.

Self-assembling nanoparticles based on cytarabine prodrug for enhanced leukemia treatment

Cytarabine (Ara-C) is an attractive chemotherapeutic agent used for the treatment of acute myeloblastic leukemia, however, its severely drawbacks such as low lipophilicity and rapid plasma degradation limit clinical applications. Here, we synthesized a new Ara-C prodrug DTA-Ara by conjugating 2-decyltetradecanoic acid (DTA), a double-chained fatty acid with 24 carbons with Ara-C. It was the first time to see that DTA-Ara molecules could self-assemble into stable spherical nanoparticles (NPs) in aqueous solution with extremely high drug loading (63wt%). The DTA-Ara NPs had the average sizes of approximately 130nm and a zeta potential around −31.6mV. Importantly, the DTA-Ara NPs were stable in deionized water or phosphate buffer solution (PBS, pH7.4) solution for more than one week and the hemolysis rate was <10%, which indicated that it could be administrated intravenously. Moreover, the in vitro cytotoxicity study further manifested that the resulting prodrug showed the marked antitumor activity against human leukemia cell line K562 and HL60 cells compared to the naked drug ascribed to its improvement of the hydrophobicity and biomembrane penetrability. The strategy of delivering lipophilized nucleoside analogs using prodrug self-assembling nanoparticles demonstrate potential superiority for Ara-C and provide a new promising therapeutic schedule for leukemia.

Biosynthesis of MgO Nanoparticles Using Lactobacillus Sp. and its Activity Against Human Leukemia Cell Lines HL-60

The present study reports a low-cost, eco-friendly, and reproducible microbes Lactobacillus sp. mediated biosynthesis magnesium oxide nanoparticles. The nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and high-resolution transmission electron microscopy (HRTEM). The morphological characteristics were found to be spherical, oval in shape, individual nanoparticles as well as a few aggregates. The XRD shows the crystallographic plane indicating that nanoparticles structure dominantly corresponds crystalline. The biosynthesized magnesium oxide nanoparticles showed corresponding functional peaks. The cytotoxic effects of the magnesium oxide nanoparticles could significantly inhibited HL-60cancer cell lines proliferation in a time and concentration-dependent manner by MTT assay. L. sporogenes mediated magnesium oxide nanoparticles had potential to inhibit the cancerous cells by 60% while L. plantarum mediated nanoparticles found to inhibit the growth by 50%. The biosynthesis of nanoparticles has been proposed as an environmental friendly and cost effective alternative to chemical and physical methods. Hence, this report added the value for the application of magnesium oxide nanoparticles in biomedical and nanotechnology applications with the absence of adverse side effects from nonpathogenic, mesophilic Lactobacillus plantarum and Lactobacillus sporogenes for the nanoparticles.

Characteristics of doxorubicin-selected multidrug-resistant human leukemia HL‑60 cells with tolerance to arsenic trioxide and contribution of leukemia stem cells

The present study selected and characterized a multidrug-resistant HL-60 human acute promyelocytic leukemia cell line, HL-60/RS, by exposure to stepwise incremental doses of doxorubicin. The drug-resistant HL-60/RS cells exhibited 85.68-fold resistance to doxorubicin and were cross-resistant to other chemotherapeutics, including cisplatin, daunorubicin, cytarabine, vincristine and etoposide. The cells over-expressed the transporters P-glycoprotein, multidrug-resistance-related protein 1 and breast-cancer-resistance protein, encoded by the adenosine triphosphate-binding cassette (ABC)B1, ABCC1 and ABCG2 genes, respectively. Unlike other recognized chemoresistant leukemia cell lines, HL-60/RS cells were also strongly cross-resistant to arsenic trioxide. The proportion of leukemia stem cells (LSCs) increased synchronously with increased of drug resistance in the doxorubicin-induced HL-60 cell population. The present study confirmed that doxorubicin-induced HL-60 cells exhibited multidrug-resistance and high arsenic-trioxide resistance. Drug-resistance in these cells may be due to surviving chemoresistant LSCs in the HL-60 population, which have been subjected to long and consecutive selection by doxorubicin.