OBJECTIVETo investigate the role of Tal1 gene, which is aberrantly expressed in 40%-60% of patients with T lymphocytic leukemia (T-ALL), in the proliferation of T-ALL cells.

METHODSWe established stable Jurkat-siTal1 and Jurkat-T1 cell lines by trasnfecting T-ALL Jurkat cells with lentiviral vectors to knock-down or overexpress Tal1. Jurkat cells transfected with negative control siRNAs for Tal1 knock-down (Jurkat-mock1) and over-expression(Jurkat-mock2) served as the control cells. The proliferation of the cells lines was assessed using CCK-8 assay, and the cell cycle distribution was determined by flow cytometry. The mRNA and protein expressions of cyclin-dependent kinase inhibitor 2 (CDKN2A) and cyclin-dependent kinase inhibitor 1 (CDKN2B) were measured by real-time RT-PCR and Western blotting, respectively.

RESULTSJurkat-T1 cells showed more active proliferation in vitro than Jurkat-mock2 cells, while Jurkat-siTal1 cells showed slower growth than Jurkat-mock1 cells. In Jurkat-T1 cells, G0/G1 phase cells were decreased and S phase cells increased compared with Jurkat-mock2 cells, and Jurkat-siTal1 cells showed increased G0/G1 phase cells and decreased S phase cells compared with Jurkat-mock1 cells. Real-time RT-PCR and Western blotting showed that Tal1 inhibited the cellular expression of CDKN2A and CDKN2B at both mRNA and protein levels.

CONCLUSIONTal1 promotes the growth and the transition from G0/G1 phase to S phase in T-ALL cells Jurkat by inhibiting the expressions of G0/G1 and S phase negative regulatory proteins CDKN2A and CDKN2B.

Apoptosis ; Basic Helix-Loop-Helix Transcription Factors ; metabolism ; Cell Cycle ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p15 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Humans ; Jurkat Cells ; Lentivirus ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; metabolism ; pathology ; Proto-Oncogene Proteins ; metabolism ; RNA, Small Interfering ; T-Cell Acute Lymphocytic Leukemia Protein 1

This study investigated the effects of miRNA-155 on malignant biological characteristics of NK/T-cell lymphoma cell lines and the possible mechanism. The expression of miRNA-155 was detected in lymphoma cell lines from different sources (SNK-6, YTS, Jurkat and DOHH2) by real-time PCR. Lentiviral vectors (pLL3.7) that could overexpress or downexpress miRNA-155 were constructed. Recombinant lentiviral particles were prepared and purified, and their titers determined. The expression of miRNA-155 in the infected SNK-6 cells and the cell proliferation were detected by PCR and CCK-8, respectively. Flow cytometry was used to determine the apoptosis of infected SNK-6 cells. The target of miRNA155 was predicted from Targetscan website. The effect of miRNA155 on FOXO3a expression was examined by Western blotting. The results showed that among the human NK/T-cell lymphoma cell lines SNK-6, YTS, Jurkat and DOHH2, the expression of miRNA-155 was highest in SNK-6. The infection efficiency of the recombinant lentivirus in SNK-6 was more than 70% at multiplicity of infection (MOI) of 100. The expression of miRNA-155 was significantly increased in SNK-6 cells infected by lentivirus vectors with high expression of miRNA-155 (4 times higher than the control group), and profoundly decreased in those infected with lentiviruses with low expression of miRNA-155. The proliferation of letivirus-infected SNK-6 cells was decreased as the expression of miRNA-155 reduced. The apoptosis rate was increased with the reduction in the expression of miRNA-155. FOXO3a was found to be a possible target of miRNA155, as suggested by Targetscan website. Western blotting showed that the expression of FOXO3a was significantly elevated in SNK-6 cells with miRNA-155 inhibition. It was concluded that reduction in miRNA-155 expression can inhibit the proliferation of SNK-6 lymphoma cells and promote their apoptosis, which may be associated with regulation of FOXO3a gene.
Apoptosis ; genetics ; Forkhead Box Protein O3 ; Forkhead Transcription Factors ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; Humans ; Jurkat Cells ; Lymphoma, T-Cell ; genetics ; metabolism ; pathology ; MicroRNAs ; biosynthesis ; genetics ; Natural Killer T-Cells ; metabolism ; pathology ; Neoplasm Proteins ; genetics ; metabolism ; RNA, Neoplasm ; biosynthesis ; genetics ; Transduction, Genetic

This study was purposed to explore the mechanism of central nervous system (CNS) leukemia resulting from brain metastasis of human acute T-cell leukemia (T-ALL) cells and the role of MIP-1α in migration of Jurkat cells through human brain microvascular endothelial cells (HBMEC). The real-time PCR, siRNA test, transendothelial migration test, endothelial permeability assay and cell adhesion assay were used to detect MIP-1α expression, penetration and migration ability as well as adhesion capability respectively. The results showed that the MIP-1α expression in Jurkat cells was higher than that in normal T cells and CCRF-HSB2, CCRF-CEM , SUP-T1 cells. The MIP-1α secreted from Jurkat cells enhanced the ability of Jurkat cells to penetrate through HBMEC, the ability of Jurkat cells treated by MIP-1α siRNA to adhere to HBMEC and to migrate trans endothelial cells decreased. It is concluded that the MIP-1α secreted from Jurkat cells participates in process of penetrating the Jurkat cells through HBMEC monolayer.
Brain Neoplasms ; pathology ; secondary ; Cell Adhesion ; Cell Movement ; Chemokine CCL3 ; metabolism ; Endothelial Cells ; pathology ; Endothelium, Vascular ; pathology ; Humans ; Jurkat Cells ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ; pathology

The activity of the mTOR pathway is frequently increased in acute myeloid leukemia, and is tightly related with cellular proliferation. Leucine is tightly linked to the mTOR pathway and can activate it, thereby stimulating cellular proliferation. LAT3 is a major transporter for leucine, and suppression of its expression can reduce cell proliferation. Here, we show that suppression of LAT3 expression can reduce proliferation of the acute leukemia cell line, K562. We investigated the mRNA and protein expression of LAT3 in several leukemia cell lines and normal peripheral blood mononuclear cells (PBMNCs) using RT-PCR and Western blotting. We also evaluated cell viability using a methyl thiazolyl tetrazolium (MTT) assay after blocking LAT3 expression with either shRNA targeted to LAT3 or a small molecular inhibitor BCH (2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid). LAT3 mRNA and protein expression was detected in leukemia cell lines, but not in normal PBMNCs. Using K562 cells, it was found that cellular proliferation and mTOR pathway activity were significantly reduced when LAT3 was blocked with either shRNA or BCH. Our results suggest that leukemia cell proliferation can be significantly suppressed by blocking LAT3. This finding may lead to a new strategy to develop clinical therapy for the treatment of acute myeloid leukemia.
Amino Acid Transport Systems, Basic ; antagonists & inhibitors ; genetics ; metabolism ; Amino Acids, Cyclic ; pharmacology ; Blotting, Western ; Cell Line, Tumor ; Cell Proliferation ; Cell Survival ; drug effects ; genetics ; Cells, Cultured ; Dose-Response Relationship, Drug ; Gene Expression Regulation, Leukemic ; genetics ; HL-60 Cells ; Humans ; Jurkat Cells ; K562 Cells ; Leukemia, Erythroblastic, Acute ; genetics ; metabolism ; pathology ; Phosphorylation ; drug effects ; RNA Interference ; Reverse Transcriptase Polymerase Chain Reaction ; TOR Serine-Threonine Kinases ; metabolism

OBJECTIVETo investigate the cytotoxic effects of mTOR inhibitor rapamycin (Rapa) and idarubicin (IDA) on human T-cell acute lymphoblastic leukemia Jurkat cell line.

METHODSThe proliferation of Jurkat cells was observed by CCK-8 assay. The combined index was analyzed by Isobologram method. Apoptosis was detected by electron microscopy and flow cytometry with Annexin V/PI staining. Protein expressions of Caspase 3, PARP, Caspase 8, Caspase 9, Akt, p-Akt, P85S6K, p-P85S6K, P70S6K, p-P70S6K, ERK1/2 and p-ERK1/2 were determined by Western blotting.

RESULTSThe IC(50) of IDA for Jurkat cells was significantly reduced when combined with 10 nmol/L rapamycin. The combined index was <1. Both electron microscopy and Annexin V/PI staining flow cytometry revealed that rapamycin significantly increased apoptotic sensitivity to IDA. The combination of IDA with rapamycin enhanced the expressions of Caspase 3, PARP, Caspase 8 and Caspase 9. Rapamycin significantly inhibited mTOR signaling upstream Akt and downstream S6K activation triggered by IDA, and the combination of the two agents led to synergistic inhibition of ERK phosphorylation.

CONCLUSIONCombination of IDA with rapamycin exerted a synergistic anti-proliferative effect and promoted apoptosis by both extrinsic and intrinsic apoptotic pathways in Jurkat cells. Inhibition of ERK phosphorylation and mTOR signaling by rapamycin may play a certain role in this synergistic effect.

Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Cell Proliferation ; drug effects ; Drug Synergism ; Humans ; Idarubicin ; pharmacology ; Jurkat Cells ; metabolism ; pathology ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ; metabolism ; pathology ; Proto-Oncogene Proteins c-akt ; metabolism ; Sirolimus ; pharmacology

The study was aimed to explore the correlation of expression of pten mRNA and PTEN protein with AKT phosphorylation levels in various types of leukemia and to elucidate its role in the pathogenesis of leukemia so as to provide some evidence for using PI3K/AKT pathway inhibitors in future. 128 de novo leukemia patients were enrolled in this study, including 61 AML cases, 27 ALL cases, 24 CML cases, and 16 CLL cases. 21 volunteers were selected as normal control. The RT-PCR and Western blot were used to assay the expressions of pten mRNA, PTEN protein, and P-AKT protein in Jurkat cells, bone marrow mononuclear cells of patients respectively. The results showed that the expressions of pten mRNA and PTEN protein in Jurkat cells were lower than that in normal control group; the expression of pten mRNA in AML group was lower than that in normal control group, but the difference was not significant (p=0.274); the expressions of pten mRNA in ALL, CML, CLL each group were lower than that in normal control group, and the difference was significant (p<0.05). Compared with normal control group, the expression of PTEN protein was lower and the expression of P-AKT protein was higher in AML, ALL, CML, CLL each group, the difference were significant (p<0.05). It is concluded that the a lower expression of PTEN protein and higher expression of P-AKT protein may play an important role on leukemia pathogenesis, and inactivation of PTEN protein mainly occurs in the level of protein translation.
Bone Marrow Cells ; metabolism ; Case-Control Studies ; Humans ; Jurkat Cells ; Leukemia ; metabolism ; pathology ; PTEN Phosphohydrolase ; metabolism ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA, Messenger ; genetics

OBJECTIVETo construct a eukaryotic expression vector of CD99 gene for transfection into Hodgkin lymphoma L428 cells.

METHODSThe full-length cDNA of CD99 gene was amplified from Jurkat cells by RT-PCR and cloned into the pcDNA3.1(+) vector and transfected into L428 cell line using Lipofextamine 2000. The sequence of CD99 mRNA in the transfected cells was confirmed by restriction endonuclease digestion and DNA sequencing, and the expression of CD99 protein was identified using immunocytochemistry.

RESULTSA gene fragment of 558 bp was amplified from the transfected cells and the sequence was verified by DNA sequencing. Immunocytochemistry identified the presence of CD99 expression in the transfected cells.

CONCLUSIONA eukaryotic expression vector pcDNA3.1(+)-CD99 is successfully constructed and stably expressed in L428 cell line.

12E7 Antigen ; Antigens, CD ; biosynthesis ; genetics ; Base Sequence ; Cell Adhesion Molecules ; biosynthesis ; genetics ; Cell Line, Tumor ; Cloning, Molecular ; Genetic Vectors ; genetics ; Hodgkin Disease ; metabolism ; pathology ; Humans ; Jurkat Cells ; Molecular Sequence Data ; Transfection

OBJECTIVETo detect the expression levels of telomere binding factor 2 (TRF2) on leukemia cell lines and primary leukemia cells.

METHODSThe expression of TRF2 mRNA was detected with quantitative real-time RT-PCR in leukemia cell lines and primary leukemia cells. The Western blot analysis was used for the detection of TRF2 protein expression.

RESULTTRF2 was overexpressed in T-cell leukemia cell lines but not in myelogenous leukemia cell lines. Significant higher expression levels of TRF2 were observed in primary leukemia cells from patients with M0 and M1 subtypes of acute myelogenous leukemia (AML) compared with normal control and other subtypes of AML.

CONCLUSIONIncreased TRF2 expression levels are found in T-cell leukemia cell lines and AML patients with poor prognosis, which suggests that TRF2 expression might be related to the prognosis of leukemia.

Adolescent ; Adult ; Female ; HL-60 Cells ; Humans ; Jurkat Cells ; K562 Cells ; Leukemia, Myeloid, Acute ; metabolism ; Leukemia, T-Cell ; metabolism ; pathology ; Male ; Middle Aged ; RNA, Messenger ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Telomeric Repeat Binding Protein 2 ; metabolism ; Young Adult

OBJECTIVETo investigate the expression variation and significance of Skp2 and p27(kip1) during the proliferation of lymphoma cell line Jurkat cells.

METHODSThe binding of p27(kip1) and Skp2 in Jurkat cells were detected by immunoprecipitation. Jurkat cells were treated with serum starvation and release synchronization. The expression variation and subcellular localization of p27(kip1) and Skp2 were detected by subcellular fractionation, Western blot and double immunofluorescence labelling.

RESULTSThe results of immunoprecipitation suggested that p27(kip1) and Skp2 could bind each other in Jurkat cells. During the proliferation of Jurkat cells, the protein expression of p27(kip1) decreased and intranuclear p27(kip1) decreased significantly, while the Skp2 protein increased and cytoplasmic Skp2 increased significantly.

CONCLUSIONDuring the proliferation of Jurkat cells, the increased cytoplasmic synthesis of Skp2 may speed up p27(kip1) degradation via the ubiquitin-proteasome pathway, then intranuclear p27(kip1) decreases significantly, leading to an increased cell cycling activity.

Cell Nucleus ; metabolism ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Cytoplasm ; metabolism ; Humans ; Jurkat Cells ; Lymphoma, B-Cell ; metabolism ; pathology ; Protein Binding ; S-Phase Kinase-Associated Proteins ; metabolism

Reactive oxygen species (ROS) performs a pivotal function as a signaling mediator in receptor-mediated signaling. However, the sources of ROS in this signaling have yet to be determined, but may include lipoxygenases (LOXs) and NADPH oxidase. The stimulation of lymphoid cells with TNF-alpha, IL-1beta, and LPS resulted in significant ROS production and NF-kappaB activation. Intriguingly, these responses were markedly abolished via treatment with the LOXs inhibitor nordihydroguaiaretic acid (NDGA). We further examined in vivo anti-inflammatory effects of NDGA in allergic airway inflammation. Both intraperitoneal and intravenous NDGA administration attenuated ovalbumin (OVA)-induced influx into the lungs of total leukocytes, as well as IL-4, IL-5, IL-13, and TNF-alpha levels. NDGA also significantly reduced serum levels of OVA-specific IgE and suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine. The results of our histological studies and flow cytometric analyses showed that NDGA inhibits OVA-induced lung inflammation and the infiltration of CD11b+ macrophages into the lung. Collectively, our findings indicate that LOXs performs an essential function in pro-inflammatory signaling via the regulation of ROS regulation, and also that the inhibition of LOXs activity may have therapeutic potential with regard to the treatment of allergic airway inflammation.
Animals ; Antioxidants/metabolism ; Asthma/complications/metabolism/pathology/physiopathology ; Bronchial Hyperreactivity/drug therapy/pathology ; Bronchial Provocation Tests ; Bronchoalveolar Lavage Fluid/cytology ; Cells, Cultured ; Drug Evaluation, Preclinical ; Humans ; Inflammation/*etiology/metabolism ; Jurkat Cells ; Lipoxygenase/*physiology ; Lipoxygenase Inhibitors/pharmacology/therapeutic use ; Lymphocytes/drug effects/metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Nordihydroguaiaretic Acid/pharmacology/therapeutic use ; Reactive Oxygen Species/*adverse effects/*metabolism