Human Leukemia Jurkat Cells Research Articles

Label-free detection of the cytotoxicity effect of cisplatin in human leukemic cells using Raman spectroscopy in conjunction with multivariate analysis.

The single-cell Raman spectra of human leukemic Jurkat cells can be obtained by confocal microscopy Raman spectroscopy, including cell groups treated with different doses of cisplatin (0, 3.5, 7, 10.5 and 14 μmol L-1) for 24 hours and those treated with 10.5 μmol L-1 cisplatin for different times (0, 6, 12, 24 and 36 hours). The structure and amount of protein, nucleic acid and other major molecules from different cell groups show special changes in the percentage of biochemical constituents. Compared with the control group, the two protein Raman bands (1449 and 1659 cm-1) and two DNA bands (1303 and 1338 cm-1) in the treatment groups decrease in intensity with the increase of the drug dose and treatment time of cisplatin. Partial least squares combined with support vector machines was used to develop diagnostic algorithms for distinguishing between control and treatment groups. The support vector machines for classification between the control group (0 μmol L-1) and cell groups treated with 10.5 and 14 μmol L-1 cisplatin for 24 hours have achieved good diagnostic results with a high sensitivity of 100%, specificity of 100% and accuracy of 100%, respectively, indicating that 10.5 μmol L-1 can be used as an appropriate therapeutic dose. Using the same method, the diagnostic sensitivity, specificity and accuracy between the control group (0 hours) and cell groups treated with 10.5 μmol L-1 cisplatin for 24 and 36 hours are all 100%, showing that 24 hours can be used as an appropriate therapeutic time. These results showed that Raman spectroscopy in conjunction with multivariate statistical analysis could be a useful tool for evaluating the cytotoxicity induced by cisplatin in human leukemic cells.

Evaluating the cytotoxicity mechanism of the cell-penetrating peptide TP10 on Jurkat cells

TP10, a classic cell-penetrating peptide, shows a high degree of similarity to AMPs in structure. Although TP10 has been widely used in drug delivery, the mechanism underlying its cytotoxicity is yet to be elucidated. Herein, we explored the cell-killing mechanism of TP10 against human leukemia Jurkat cells. TP10 induced necrosis in Jurkat cells via rapid disruption of cell membranes, particularly at high concentrations. Although mitochondria in Jurkat cells were damaged by TP10, mitochondria-mediated apoptosis did not occur, possibly due to intracellular ATP depletion. Necroptosis in TP10-treated Jurkat cells became an alternative route of apoptosis. Our results demonstrate that necrosis and necroptosis rather than apoptosis are involved in the cell-killing mechanism of TP10, which contributes to the understanding of its toxicity.

MiR-708 regulates the biological behavior of childhood leukemia cells by binding to the 3'utr end of the target gene and reducing the level of the target gene.

This study was performed to analyze the biological behavior of childhood leukemia cells regulated by miR-708 by binding to the 3&apos; UTR end of the target gene and reducing the level of the target gene. In this regard, human leukemia Jurkat cell lines were selected and divided into a control group, miR-708 overexpression group and miR-708 inhibition group. MTT assay was used to detect the cell proliferation inhibition rate, flow cytometry was used to detect the apoptosis rate and cell cycle change, the scratch test was used to detect the cell migration capacity, and Western Blot assay was used to detect the expression of CNTFR, apoptosis and JAK/STAT pathway related proteins. To verify the binding site of miR-708 and target gene CNTFR. The results showed that the cell proliferation inhibition rate, apoptosis rate, G1 phase ratio, Bax protein, and CNTFR protein in the miR-708 overexpression group were significantly lower than those in the control group at each time point, while the S phase ratio, Bcl-2 protein, cell migration ability, JAK3 and STAT3 protein were significantly higher than those in the control group (P<0.05). The results of the miR-708 inhibition group were contrary to those of the miR-708 overexpression group. The binding sites of miR-708 and CNTFR were predicted by TargetScan bioinformatics software. It was found that there were two binding sites of miR-708 and CNTFR, 394-400 bp and 497-503 bp respectively. In conclusion, miR-708 can reduce the expression of CNTFR by binding to the target gene CNTFR3&apos; UTR, activate the JAK/STAT pathway to regulate apoptosis-related proteins, reduce apoptosis, and enhance the migration ability of leukemia cells.

Molecular Mechanisms Responsible for In Vitro Cytotoxic Attributes of Conyza bonariensis Extract against Lymphoblastic Leukaemia Jurkat Cells.

Conyza bonariensis is known to have anti-cancer properties. The current study investigated the in vitro pro-apoptotic properties of Conyza bonariensis (C. bonariensis) towards human lymphoblastic leukemia Jurkat cells. Ariel parts of C. bonariensis were macerated in a non-polar (n-Hexane) solvent. MTS cell viability assay was employed to determine the cytotoxic activity of the extract towards human leukemia Jurket cells and normal Peripheral Blood Mononuclear Cells (PBMCs). The phytochemical composition of the extract was screened using HPLC method. Flow cytometric studies (FACS) were conducted to explore the pro-apoptotic potential of the extract. Western blot studies were employed to identify the molecular targets involved in the induction of apoptosis. The n-hexane extract showed selective cytotoxic activity towards Jurkat cells. FACS analysis indicated that the extract induced early and late apoptosis in Jurkat cells. Western blot studies revealed that the extract downregulated the expression of DNMT1, SIRT1, and UHRF1 with a simultaneous up-regulation of p73 and caspases-3 proteins expression. HPLC characterization of the extract revealed the presence of phenolic compounds. Overall, these findings demonstrate that the anti-cancer effects of a Conyza bonariensis extract towards human lymphoblastic leukemia Jurkat cells are due to the modulation of the activity of multiple oncogenic and tumor suppressor proteins. Phenolic contents of the extract are proposed to be responsible for these activities.

Apoptotic Effects of a Thioether Analog of Vitamin K3 in a Human Leukemia Cell Line.

Research suggests that thioether analogs of vitamin K3 (VK3) can act to preserve the phosphorylation of epidermal growth factor receptors by blocking enzymes (phosphatases) responsible for their dephosphorylation. Additionally, these derivatives can induce apoptosis via mitogen-activated protein kinase and caspase-3 activation, inducing reactive oxygen species (ROS) production, and apoptosis. However, vitamin K1 exhibits only weak inhibition of phosphatase activity, while the ability of VK3 to cause oxidative DNA damage has raised concerns about carcinogenicity. Hence, in the current study, we designed, synthesized, and screened a number of VK3 analogs for their ability to enhance phosphorylation activity, without inducing off-target effects, such as DNA damage. 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay revealed that each analog produced a different level of cytotoxicity in the Jurkat human leukemia cell line; however, none elicited a cytotoxic effect that differed significantly from that of the control. Of the VK3 analogs, CPD5 exhibited the lowest EC50, and flow cytometry results showed that apoptosis was induced at final concentrations of ≥10μM; hence, only 0.1, 1, and 10μM were evaluated in subsequent assays. Furthermore, CPD5 did not cause vitamin K-attributed ROS generation and was found to be associated with a significant increase in caspase 3 expression, indicating that, of the synthesized thioether VK3 analogs, CPD5 was a more potent inducer of apoptosis than VK3. Hence, further elucidation of the apoptosis-inducing effect of CPD5 may reveal its efficacy in other neoplastic cells and its potential as a medication.

Targeting Itch/p73 pathway by thymoquinone as a novel therapeutic strategy for cancers with p53 mutation

The tumor suppressor p73 is a member of p53 family and has a high degree of similarity with p53 function and structure. Like p53, p73 can also induce the expression of several genes involved in cell cycle and apoptosis. p73 expression is downregulated in many tumors by several mechanisms including the ubiquitination pathway. Thus, understanding the ubiquitin-proteasome pathway in p73 regulation will help in targeting this later and develop a new promising therapeutic strategy for cancer with p53 mutations. The aim of this study was to evaluate the effect of Thymoquinone (TQ), the major biologically active compound of the black seed oil on the expression of several E3 ubiquitin ligase enzymes known to be regulators of p73 and the related events in cancer cells with p53 mutation, such as the human acute lymphoblastic leukemia Jurkat cells, the human triple-negative breast cancer (MDA-MB-468 cells) and human promyelocytic leukemia HL60 cells. RNA-seq data showed that several E3 ubiquitin-ligase enzymes, well documented to be involved in the degradation of p73 including Itch, Pirh2, E3s Pin2, Mdm2, TRIM32 and SCFFBXO45 were downregulated in Jurkat cells. Among the target genes, Itch was significantly downregulated in TQ-treated Jurkat cells as compared with control cells. TQ-induced Itch downregulation was confirmed by real-time RT-PCR in Jurkat cells, MDA-MB-468 cells and HL60. Treating Jurkat cells with either TQ or the proteasome inhibitor MG132 induced an upregulation of p73. The present study indicates that TQ could be a promising inhibitor of the E3-ubiquitin ligase Itch leading to the upregulation of tumor suppressor p73 in cancers expressing mutant p53.

Dihydroartemisinin Induces Apoptosis of Human Acute T Lymphocytic Leukemia Cells by Activating Oxidative Stress

To investigate the effects of dihydroartemisinin (DHA) on the proliferation and apoptosis of human T-cell acute lymphoblastic leukemia (T-ALL) Jurkat cell. The effects of DHA on the proliferation of Jurkat cells and the recovery of DHA-inhibited cell viability by N-acetyl-L-cysteine (NAC) were examined by CCK-8 assay. Flow cytometry was performed to analyze the cell apoptosis and generation of reactive oxygen species (ROS). Western-blot was used to detected protein expression of DNA damage-related genes, as well as apoptosis-associated genes, respectively. DHA inhibited the proliferation of Jurkat cells, and shows a concentration-dependent manner(r =0.936), and NAC could partially restore the activity of DHA on cell proliferation inhibition. With the increase of drug concentration, the apoptosis rate (r =0.946) and ROS accumulation was increased (r =0.965). Western blot showed that the protein expressions of DNA damage-related gene γ-H2AX and apoptosis-related genes p53, c-Caspase3, BAX and cPARP were significantly increased, and BCL-2 protein expression was decreased. DHA can induce ROS production in Jurkat cells, which can cause DNA damage, activate the P53 apoptotic pathway, and promote apoptosis of cells.

Fli-1 promotes proliferation and upregulates NANOGP8 expression in T-lymphocyte leukemia cells

Friend leukemia integration 1 (Fli-1) is a member of the E26 transformation-specific (ETS) transcription factor family. Fli-1 regulates normal hematopoiesis and vasculogenesis, and its aberrant expression underlies virus-induced leukemias and various types of human cancers. NANOGP8, a retro-pseudogene of stem cell mediator NANOG, is expressed predominantly in cancer cells and plays a role in tumorigenesis. In this study, we demonstrate that Fli-1 expression enhances human acute T-cell leukemia Jurkat cell proliferation and that Fli-1 acts as a transcriptional activator of NANOGP8 expression in these cells. NANOGP8 and Fli-1 are highly expressed in Jurkat cells, whereas NANOG was undetectable at both the RNA and protein levels. Moreover, the expression of endogenous NANOGP8 was significantly influenced by gain of function and loss of function of Fli-1. Promoter-reporter assays showed that NANOGP8 transcription was significantly upregulated by dose-dependent Fli-1 overexpression. A series of deletion mutagenesis of NANOGP8 promoter sequence revealed that NANOGP8 promoter activity was tightly regulated and found the minimal promoter region sufficient to activate NANOGP8 transcription mediated by Fli-1. Moreover, site-directed mutagenesis of the putative binding site abolished both NANOGP8 full-length and minimal promoter activities. Binding assays revealed that Fli-1 directly interacts with the potent binding site in NANOG promoter region. Taken together, our data demonstrate that Fli-1 is a novel upstream transcriptional activator of NANOGP8 and provide the molecular details of Fli-1-mediated NANOGP8 gene expression. Ultimately, these findings may contribute to understanding the expanded regulatory mechanisms of oncogenic NANOGP8 and ETS family transcription factors in leukemogenesis.

Induction of caspase-2 gene expression in carboxyl-functionalized carbon nanotube-treated human T-cell leukemia (Jurkat) cell line

Carbon nanotubes (CNTs) have great potential as novel diagnostic or therapeutic tools in biomedicine but, cellular toxicity must be well considered before widespread application of CNTs. Many chemical agents exert their toxicity through apoptotic pathways by induction of caspase biomolecules. In the current study, effects of carboxyl-functionalized single-walled (SW) and multi-walled (MW) CNTs at a single dose of 100 µg ml−1 on the survival of Jurkat cells were examined using MTT assay. Additionally, the impacts of carboxylated CNTs on the gene expression levels of selected caspases were investigated. Jurkat cells were exposed to CNTs (100 µg ml−1 for 72 h) and then expression levels of selected caspase genes (Cas) were evaluated by qRT-PCR analysis. Housekeeping genes, β-actin, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH), were used as normalization controls. The results showed only a mild decrease in the viability of Jurkat cells treated with carboxylated MWCNT. The results of qRT-PCR analysis revealed the elevated level of Cas2 mRNA in the cells treated with carboxylated MWCNT (6.08-fold) and carboxylated SWCNT (1.20-fold). The expression levels of Cas4, Cas6, Cas8, and Cas10 genes were increased not significantly compared to the control untreated cells. Our findings suggested that exposure to carboxyl-functionalized CNTs could be resulted in up-regulation of the Cas2 gene and not initiator Cas8 and Cas10 genes. In addition, it seems that carboxylated MWCNT was more potent than SWCNT in activation of Cas2 gene expression and triggering cell death signal in a manner different from intrinsic or extrinsic apoptosis pathways.

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.

ABT-263-induced MCL1 upregulation depends on autophagy-mediated 4EBP1 downregulation in human leukemia cells

The present study aimed to investigate the pathway related to MCL1 expression in ABT-263-treated human leukemia U937 cells. ABT-263 upregulated MCL1 protein expression but did not affect its mRNA level and protein stability. Notably, ABT-263 increased 4EBP1 mRNA decay and thus reduced 4EBP1 expression. Overexpression of 4EBP1 abrogated ABT-263-induced MCL1 upregulation. ABT-263-induced activation of IKKα/β-NFκB axis elicited autophagy of U937 cells, leading to reduced mRNA stability of 4EBP1. Inhibition of the IKKα/β-NFκB axis or autophagy mitigated the effect of ABT-263 on 4EBP1 and MCL1 expression. Amsacrine enhanced the cytotoxicity of ABT-263 in human leukemia U937, HL-60, and Jurkat cells because of its inhibitory effect on the IKKα/β-NFκB-mediated pathway. Our data indicate that ABT-263 alleviates the inhibitory effect of 4EBP1 on MCL1 protein synthesis through IKKα/β-NFκB-mediated induction of autophagy, and suggest a promising strategy to improve anti-leukemia therapy with ABT-263.

Synthesis of Nerol Derivatives Containing a 1,2,3-Triazole Moiety and Evaluation of Their Activities against Cancer Cell Lines

In the present investigation, a collection of twenty two nerol derivatives, containing 1,2,3-triazolic appendages, was synthesized and screened in vitro for their cytotoxic activity against HL60, Nalm6, and Jurkat human leukemia cells as well as against B16F10 (melanoma cell line). In most cases, derivatives were able to reduce cell viability. The most potent compound (Z)-4-(((3,7-dimethylocta-2,6-dien-1-yl)oxy)methyl)-1-(4-(trifluoromethoxy)benzyl)-1H-1,2,3 triazole showed antiproliferative activity against Jurkat cells and reduced B16F10 cell migration. Physicochemical properties of the compounds were calculated in order to evaluate their potential for drug development. Most of the evaluated physicochemical parameters seemed to be favorable for drug development. In addition, for a better understanding of the biological activity results, 3D quantitative structure-activity relationship (QSAR) studies were carried out. 3D-QSAR studies indicate that the anticancer activities observed for the cell lines HL60 and Jurkat may occur by a similar mechanism of action and the same was found for the Nalm6 and B16F10 cell lines.

Caspase-mediated cleavage of X-ray repair cross-complementing group 4 promotes apoptosis by enhancing nuclear translocation of caspase-activated DNase

X-ray repair cross-complementing group 4 (XRCC4), a repair protein for DNA double-strand breaks, is cleaved by caspases during apoptosis. In this study, we examined the role of XRCC4 in apoptosis. Cell lines, derived from XRCC4-deficient M10 mouse lymphoma cells and stably expressing wild-type XRCC4 or caspase-resistant XRCC4, were established and treated with staurosporine (STS) to induce apoptosis. In STS-induced apoptosis, expression of wild-type, but not caspase-resistant, XRCC4 in XRCC4-deficient cells enhanced oligonucleosomal DNA fragmentation and the appearance of TUNEL-positive cells by promoting nuclear translocation of caspase-activated DNase (CAD), a major nuclease for oligonucleosomal DNA fragmentation. CAD activity is reportedly regulated by the ratio of two inhibitor of CAD (ICAD) splice variants, ICAD-L and ICAD-S mRNA, which, respectively, produce proteins with and without the ability to transport CAD into the nucleus. The XRCC4-dependent promotion of nuclear import of CAD in STS-treated cells was associated with reduction of ICAD-S mRNA and protein, and enhancement of phosphorylation and nuclear import of serine/arginine-rich splicing factor (SRSF) 1. These XRCC4-dependent, apoptosis-enhancing effects were canceled by depletion of SRSF1 or SR protein kinase (SRPK) 1. In addition, overexpression of SRSF1 in XRCC4-deficient cells restored the normal level of apoptosis, suggesting that SRSF1 functions downstream of XRCC4 in activating CAD. This XRCC4-dependent, SRPK1/SRSF1-mediated regulatory mechanism was conserved in apoptosis in Jurkat human leukemia cells triggered by STS, and by two widely used anti-cancer agents, Paclitaxel and Vincristine. These data imply that the level of XRCC4 expression could be used to predict the effects of apoptosis-inducing drugs in cancer treatment.

Rice protein prolamin promotes anti-leukemia immunity and inhibits leukemia growth in vivo

Prolamin is a heat-stable storage protein of rice (Oryza sativa). This study aimed to examine the effect of prolamin on anti-tumor immune response in vitro and leukemia growth in vivo. The prolamin-enriched rice fractions were prepared to stimulate peripheral blood mononuclear cells (MNC) from mice spleen. The MNC-conditioned medium (MNC-CM) was collected to treat leukemia L1210 cells. Human MNC-CM was prepared to treat Jurkat acute T cell leukemia cells. Purified prolamin was orally administered to syngeneic L1210-bearing DBA/2 mice to assess weights of tumor, liver and spleen, liver histopathology, peripheral blood neutrophil count and cytokine levels. Prolamin-prepared MNC-CM inhibited the viability of murine leukemia L1210 cells and human leukemia Jurkat cells, indicating an immunomodulatory effect. In syngeneic L1210-bearing DBA/2 mice, oral administration of purified prolamin dose-dependently decreased the tumor weight and attenuated the leukemia-induced reduction of liver and spleen weights. Prolamin inhibited the increase of peripheral blood leukocyte count. The levels of tumor necrosis factor-α and interferon-γ in MNC-CM and mice serum were significantly increased by prolamin treatment. No significant change in body weight, serum alanine aminotransferase and creatinine levels was noted by prolamin treatment. Rice prolamin could effectively promote anti-tumor immunity and inhibit leukemia growth without significant toxicity.

Up-regulated Ectonucleotidases in Fas-Associated Death Domain Protein– and Receptor-Interacting Protein Kinase 1–Deficient Jurkat Leukemia Cells Counteract Extracellular ATP/AMP Accumulation via Pannexin-1 Channels during Chemotherapeutic Drug-Induced Apoptosis

Pannexin-1 (Panx1) channels mediate the efflux of ATP and AMP from cancer cells in response to induction of extrinsic apoptosis by death receptors or intrinsic apoptosis by chemotherapeutic agents. We previously described the accumulation of extracellular ATP /AMP during chemotherapy-induced apoptosis in Jurkat human leukemia cells. In this study, we compared how different signaling pathways determine extracellular nucleotide pools in control Jurkat cells versus Jurkat lines that lack the Fas-associated death domain (FADD) or receptor-interacting protein kinase 1 (RIP1) cell death regulatory proteins. Tumor necrosis factor-α induced extrinsic apoptosis in control Jurkat cells and necroptosis in FADD-deficient cells; treatment of both lines with chemotherapeutic drugs elicited similar intrinsic apoptosis. Robust extracellular ATP/AMP accumulation was observed in the FADD-deficient cells during necroptosis, but not during apoptotic activation of Panx1 channels. Accumulation of extracellular ATP/AMP was similarly absent in RIP1-deficient Jurkat cells during apoptotic responses to chemotherapeutic agents. Apoptotic activation triggered equivalent proteolytic gating of Panx1 channels in all three Jurkat cell lines. The differences in extracellular ATP/AMP accumulation correlated with cell-line-specific expression of ectonucleotidases that metabolized the released ATP/AMP. CD73 mRNA, and αβ-methylene-ADP-inhibitable ecto-AMPase activity were elevated in the FADD-deficient cells. In contrast, the RIP1-deficient cells were defined by increased expression of tartrate-sensitive prostatic acid phosphatase as a broadly acting ectonucleotidase. Thus, extracellular nucleotide accumulation during regulated tumor cell death involves interplay between ATP/AMP efflux pathways and different cell-autonomous ectonucleotidases. Differential expression of particular ectonucleotidases in tumor cell variants will determine whether chemotherapy-induced activation of Panx1 channels drives accumulation of immunostimulatory ATP versus immunosuppressive adenosine within the tumor microenvironment.

Ginsenoside Rh2 and Rg3 inhibit cell proliferation and induce apoptosis by increasing mitochondrial reactive oxygen species in human leukemia Jurkat cells.

Ginsenoside Rh2 (GRh2) and ginsenoside Rg3 (GRg3) are primary bioactive components in Panax ginseng. The present study aimed to investigate the underlying mechanisms of apoptotic cell-death induced by GRh2 and GRg3 in human leukemia Jurkat cells. The Cell Counting kit-8 assay was used to determine cell proliferation. Apoptosis was detected by nuclear morphologic observation by Hoechst 33342 staining and Annexin V-allophycocyanin and 7-amino-actinomycin D assay. mitoTEMPO, a mitochondrial reactive oxygen species (ROS) scavenger, was used to examine the effects of mitochondrial ROS on cell viability and mitochondrial membrane potential (MMP). Finally, the expression levels of numerous mitochondrial-associated apoptosis proteins were assessed by western blot analysis. These results demonstrated that GRh2 and GRg3 inhibited cell growth and induced apoptosis, and that GRh2 had greater cytotoxicity than GRg3. GRh2 induced generation of more mitochondrial ROS compared with GRg3 in Jurkat cells; however, this effect was ameliorated by subsequent treatment with mitoTEMPO. Furthermore, excess mitochondrial ROS induced by GRh2 was more potent than GRg3 in inhibiting cell proliferation and reducing MMP. In addition, expression levels of apoptosis-associated proteins were significantly increased in Jurkat cells treated with GRh2 than GRg3. In conclusion, these findings suggested that GRh2 and GRg3 induce mitochondrial-associated apoptosis by increasing mitochondrial ROS in human leukemia Jurkat cells. GRh2 may more effectively inhibit cell growth and accelerate apoptosis than GRg3. This study provides a potential novel strategy for the treatment of acute lymphoblastic leukemia.

Role of epigenetic regulation on the induction of apoptosis in Jurkat leukemia cells by white grape pomace rich in phenolic compounds.

Grape pomace is a rich source of phenolic compounds commonly employed for elaboration of dietary supplements. The aim of the present study was to investigate the anticancer effect of a purified white grape pomace extract (PWGPE) in acute lymphoblastic leukemia Jurkat cells and to characterize the underlying mechanism. Apoptosis, mitochondrial membrane potential and reactive oxygen species (ROS) levels were assessed by flow cytometry and protein expression levels were analysed by Western blotting. PWGPE induced apoptosis in Jurkat cells in a time- and concentration-dependent manner. The anticancer effect was associated with an increased expression of p73 and down-regulation of pro-survival factors, including p-Akt, Bcl-2, and survivin. PWGPE reduced the expression of several proteins that block the expression of apoptosis-related genes such as DNMT1, HDAC1/2, UHRF1, and the polycomb group protein members: EZH2, SUZ12, and BMI1. In addition, the extract induced the formation of ROS, whereas pre-treatment with PEG-catalase and N-acetylcysteine prevented the ROS formation and markedly decreased the induction of apoptosis. These findings suggest that PWGPE-induced apoptosis in Jurkat human leukemia cells, is mediated by mitochondrial depolarization and caspase-3 cleavage, and depends on ROS generation and regulation of epigenetic gene silencing. Therefore, PWGPE may play an important role in the treatment of acute lymphoblastic leukemia (ALL).

Andrographolide inhibits growth of human T-cell acute lymphoblastic leukemia Jurkat cells by downregulation of PI3K/AKT and upregulation of p38 MAPK pathways.

T-cell acute lymphoblastic leukemia (T-ALL) as a prevalent hematologic malignancy is one of the most common malignant tumors worldwide in children. Andrographolide (Andro), the major active component from Andrographis paniculata, has been shown to possess antitumor activities in several types of cancer cells. However, whether Andro would inhibit T-ALL cell growth remains unclear. In this study, we investigated the cytotoxic effect of Andro on human T-ALL Jurkat cells and explored the mechanisms of cell death. Cell apoptosis was assayed by flow cytometry, and the signaling transduction for Andro was analyzed by Western blotting. The results indicated 10 μg/mL Andro could significantly induce Jurkat cells’ apoptosis, depending on the inhibition of PI3K/AKT pathway. Moreover, Andro-induced apoptosis is enhanced by AKT-selective inhibitor LY294002. ERK- or JNK-selective inhibitors PD98059 and SP600125 had no effect on Andro-induced apoptosis. In addition, p38 inhibitor SB203580 could reverse Andro-induced apoptosis in Jurkat cells. We also found that the protein expression of p-p53 and p-p38 were increased after Andro treatments. The result of an in vivo study also demonstrated Andro’s dose-dependent inhibition in subcutaneous Jurkat xenografts. In conclusion, our findings explained a novel mechanism of drug action by Andro in Jurkat cells and suggested that Andro might be developed into a new candidate therapy for T-ALL patients in the coming days.

Fermented Brown Rice Extract Causes Apoptotic Death of Human Acute Lymphoblastic Leukemia Cells via Death Receptor Pathway.

Mixture of brown rice and rice bran fermented with Aspergillus oryzae, designated as FBRA, has been reported to reveal anti-carcinogenic and anti-inflammatory effects in rodents. Then, to test its potential anti-cancer activity, the aqueous extract was prepared from FBRA powder, and the effect of this extract on human acute lymphoblastic leukemia Jurkat cells was directly examined. The exposure to FBRA extract reduced the cell viability in a concentration- and time-dependent manner. The reduction of the cell viability was accompanied by the DNA fragmentation, and partially restored by treatment with pan-caspase inhibitor. Further studies showed that FBRA extract induced the cleavage of caspase-8, -9, and -3, and decreased Bcl-2 protein expression. Moreover, the expression of tBid, DR5, and Fas proteins was enhanced by FBRA extract, and the pretreatment with caspase-8 inhibitor, but not caspase-9 inhibitor, restored the reduction of the cell viability induced by FBRA extract. These findings suggested that FBRA extract could induce the apoptotic death of human acute lymphoblastic leukemia cells probably through mainly the death receptor-mediated pathway and supplementarily through the tBid-mediated mitochondrial pathway, proposing the possibility that FBRA was a potential functional food beneficial to patients with hematological cancer.

Molecular Cytotoxic Mechanisms of 1-(3,4,5-Trihydroxyphenyl)-dodecylbenzoate in Human Leukemia Cell Lines.

Recent studies have shown that gallic acid and its alkylesters induce apoptosis in different cell lines. Since new compounds with biological activity and less cytotoxicity to normal cells are necessary for cancer therapy, the aim of this study was to evaluate the cytotoxic effect of 1-(3,4,5-trihydroxyphenyl)-dodecylbenzoate on human acute myeloid leukemia K562 cells and on human acute lymphoblastic leukemia Jurkat cells. The cell viability was determined by MTT method. The apoptosis induction was assessed by bromide and acridine orange staining and by Annexin V-FITC Apoptosis Detection kit. The cell cycle analysis was carried out by flow cytometry using propidium iodide. Cytometric analysis was also performed to evaluate the expression of the following proteins: AIF, p53, Bcl-2 and Bax. The mitochondrial potential was also assessed by flow cytometry using MitoView633 kit. The results showed that the compound significantly reduced the cell viability of K562 and Jurkat cells in a concentration and time dependent manner (IC50 of 30 μM). The compound induced cell cycle arrest in G0/G1phase and significantly increased the proportion of cells in the sub-G0/G1phase. Apoptosis was confirmed by the sight of morphological characteristics of apoptosis and by phosphatidylserine externalization (73.47±5.71% of cells expressing annexin). The results also showed that the compound promotes a modification in Bax:Bcl-2 ratio and increases p53 expression. Thus, it is possible to conclude that 1-(3,4,5-trihydroxyphenyl)-dodecylbenzoate induces apoptosis by inhibiting the antiapoptotic protein Bcl-2 and by increasing the release of AIF, Bax and p53. In addition, it blocks the cell cycle at G0/G1, stopping cell proliferation. So far, the results suggest that this compound may have a potential therapeutic effect against leukemia cells.