Cell Cycle-Related Protein Kinases and T Cell Death

Background The bark of Uncaria rhynchophylla has been traditionally used to treat convulsion, bleeding, hypertension, auto-immune conditions, cancer, and other diseases. The main focus of this research is done for the purpose of exploring the antitumor activity and mechanism of action (MOA) for hirsutine isolated from U. rhynchophylla. Methods Jurkat clone E6-1 cells were treated using 10, 25 and 50 μM for 48 h. Inhibition of cell proliferation due to hirsutine treatment was evaluated by CCK8 assay. Flow cytometry was applied to ascertain Jurkat cell cycle progression and apoptosis after treatment with 10, 25 and 50 μM hirsutine for 48 h. The expression and level of the apoptosis-related genes and proteins was analyzed by Real-time Quantitative polymerase chain reaction (qPCR) and Western blotting method, respectively. Results CCK8 analyses revealed that hirsutine could significantly inhibit the proliferation of Jurkat clone E6-1 cells, in a concentration and time-dependent fashion. Flow cytometry assays revealed that hirsutine could drive apoptotic death and G0/G1 phase arrest in Jurkat cells. Apoptotic cells frequencies were 4.99 ± 0.51%, 13.69 ± 2.00% and 40.21 ± 15.19%, and respective cell cycle arrest in G0/G1 accounted for 34.85 ± 1.81%, 42.83 ± 0.70% and 49.12 ± 4.07%. Simultaneously, compared with the control group, Western blot assays indicated that the up-regulation of pro-apoptotic Bax, cleaved-caspase3, cleaved-caspase9 and Cyto c proteins, as well as the down-regulation of Bcl-2 protein which guards against cell death, might be correlated with cell death induction and inhibition of cell proliferation. QPCR analyses indicated that hirsutine could diminish BCL2 expression and, at the same time, improve Bax, caspase-3 and caspase-9 mRNA levels, thus reiterating a putative correlation of hirsutine treatment in vitro with apoptosis induction and inhibition of cell proliferation (p-value < 0.05). Excessive hirsutine damages the ultrastructure in mitochondria, leading to the release of Cyt c from the mitochondria to cytoplasm in Jurkat clone E6-1 cells, thereby inducing the activated caspase cascade apoptosis process through a mitochondria-mediated pathway. Conclusion An important bioactive constituent—hirsutine—appears to have antitumor effects in human T-cell leukemia, thus enlightening the use of phytomedicines as a novel source for tumor therapy. It is speculated that hirsutine may induce apoptosis of Jurkat Clone E6-1 cells through the mitochondrial apoptotic pathway.

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Satureja hortensis induces cell death and inhibited cell cycle progression in K562 myelogenous and Jurkat T cell leukemia cell lines

Journal of Immunoassay and Immunochemistry ◽

10.1080/15321819.2019.1629592 ◽

2019 ◽

Vol 40 (5) ◽

pp. 459-472

Author(s):

Morvarid Asadipour ◽

Zahra Amirghofran

Keyword(s):

Cell Cycle ◽

Cell Death ◽

T Cell ◽

Cell Lines ◽

Cell Cycle Progression ◽

Leukemia Cell ◽

Cell Leukemia ◽

Cycle Progression ◽

Leukemia Cell Lines ◽

Jurkat T Cell

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CTLA-4 engagement inhibits IL-2 accumulation and cell cycle progression upon activation of resting T cells.

Journal of Experimental Medicine ◽

10.1084/jem.183.6.2533 ◽

1996 ◽

Vol 183 (6) ◽

pp. 2533-2540 ◽

Cited By ~ 604

Author(s):

M F Krummel ◽

J P Allison

Keyword(s):

Cell Cycle ◽

T Cells ◽

Cell Death ◽

T Cell ◽

T Cell Activation ◽

Cell Cycle Progression ◽

Cell Activation ◽

Apoptotic Cell ◽

Activated T Cells ◽

Activated State

While interactions between CD28 and members of the B7 family costimulate and enhance T cell responses, recent evidence indicates that the CD28 homologue CTLA-4 plays a downregulatory role. The mechanism by which this occurs is not clear, but it has been suggested that CTLA-4 terminates ongoing responses of activated T cells, perhaps by induction of apoptosis. Here we demonstrate that CTLA-4 engagement by antibody cross-linking or binding to B7 inhibits proliferation and accumulation of the primary T cell growth factor, IL-2, by cells stimulated with anti-CD3 and anti-CD28. This inhibition is not a result of enhanced cell death. Rather it appears to result from restriction of transition from the G1 to the S phase of the cell cycle. Our observation that upregulation of both the IL-2R alpha chain and the CD69 activation antigen are inhibited by CTLA-4 engagement supplies further evidence that CTLA-4 restricts the progression of T cells to an activated state. Together this data demonstrates that CTLA-4 can regulate T cell activation in the absence of induction of apoptotic cell death.

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Activation-induced T-cell death is cell cycle dependent and regulated by cyclin B.

Molecular and Cellular Biology ◽

10.1128/mcb.15.2.932 ◽

1995 ◽

Vol 15 (2) ◽

pp. 932-942 ◽

Cited By ~ 78

Author(s):

R Fotedar ◽

J Flatt ◽

S Gupta ◽

R L Margolis ◽

P Fitzgerald ◽

...

Keyword(s):

Cell Cycle ◽

T Cells ◽

Cell Death ◽

T Cell ◽

Programmed Cell Death ◽

Kinase Activity ◽

Apoptotic Cell ◽

Cyclin B ◽

Activation Induced Cell Death ◽

Diagnostic Characteristics

Developing thymocytes and some T-cell hybridomas undergo activation-dependent programmed cell death. Although recent studies have identified some critical regulators in programmed cell death, the role of cell cycle regulation in activation-induced cell death in T cells has not been addressed. We demonstrate that synchronized T-cell hybridomas, irrespective of the point in the cell cycle at which they are activated, stop cycling shortly after they reach G2/M. These cells exhibit the diagnostic characteristics of apoptotic cell death. Although p34cdc2 levels are not perturbed after activation of synchronously cycling T cells, cyclin B- and p34cdc2-associated histone H1 kinase activity is persistently elevated. This activation-dependent induction of H1 kinase activity in T cells is associated with a decrease in the phosphotyrosine content of p34cdc2. We also demonstrate that transient inappropriate coexpression of cyclin B with p34cdc2 induces DNA fragmentation in a heterologous cell type. Finally, in T cells, cyclin B-specific antisense oligonucleotides suppress activation-induced cell death but not cell death induced by exposure to dexamethasone. We therefore conclude that a persistent elevation of the level of cyclin B kinase is required for activation-induced programmed T-cell death.

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T Cell Receptor (TCR)-β Gene Recombination: Dissociation from Cell Cycle Regulation and Developmental Progression During T Cell Ontogeny

Journal of Experimental Medicine ◽

10.1084/jem.185.9.1549 ◽

1997 ◽

Vol 185 (9) ◽

pp. 1549-1556 ◽

Cited By ~ 90

Author(s):

Michelle R. Tourigny ◽

Svetlana Mazel ◽

Douglas B. Burtrum ◽

Howard T. Petrie

Keyword(s):

Cell Cycle ◽

Cell Death ◽

T Cell ◽

Programmed Cell Death ◽

T Cell Receptor ◽

Cell Receptor ◽

Gene Recombination ◽

Developmental Progression ◽

Cell Cycle Status ◽

Cell Ontogeny

T cell lymphopoiesis involves extensive cell division and differentiation; these must be balanced by export and programmed cell death to maintain thymic homeostasis. Details regarding the nature of these processes, as well as their relationships to each other and to the definitive process of T cell receptor (TCR) gene recombination, are presently emerging. Two widely held concepts are that cell cycle status is inherently and inversely linked to gene recombination and that the outcomes of gene recombination regulate developmental progression. In this study, we analyze TCR-β recombination and cell cycle status with respect to differentiation during early T cell ontogeny. We find that although differentiation, cell cycle fluctuations, and gene recombination are coincident during normal T cell development, differentiation and cell cycle status are not inherently linked to the recombination process or its products. Rather, recombination appears to occur in parallel with these events as part of a genetically patterned program of development. We propose that the outcome of gene recombination (i.e., TCR expression) may not influence developmental progression per se, but instead serves to perpetuate those developing cells that have been successful in recombination. The potential consequences of this model for the regulation of thymic lymphopoiesis and programmed cell death are discussed.

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T Cell Receptor-induced Activation and Apoptosis In Cycling Human T Cells Occur throughout the Cell Cycle

Molecular Biology of the Cell ◽

10.1091/mbc.10.12.4441 ◽

1999 ◽

Vol 10 (12) ◽

pp. 4441-4450 ◽

Cited By ~ 15

Author(s):

Michael Karas ◽

Tal Z. Zaks ◽

Liu JL ◽

Derek LeRoith

Keyword(s):

Cell Cycle ◽

T Cells ◽

Cell Death ◽

T Cell ◽

T Cell Receptor ◽

Fas Ligand ◽

Cell Receptor ◽

Receptor Activation ◽

Activation Induced Cell Death ◽

Human T Cells

Previous studies have found conflicting associations between susceptibility to activation-induced cell death and the cell cycle in T cells. However, most of the studies used potentially toxic pharmacological agents for cell cycle synchronization. A panel of human melanoma tumor-reactive T cell lines, a CD8+ HER-2/neu-reactive T cell clone, and the leukemic T cell line Jurkat were separated by centrifugal elutriation. Fractions enriched for the G0–G1, S, and G2–M phases of the cell cycle were assayed for T cell receptor-mediated activation as measured by intracellular Ca2+flux, cytolytic recognition of tumor targets, and induction of Fas ligand mRNA. Susceptibility to apoptosis induced by recombinant Fas ligand and activation-induced cell death were also studied. None of the parameters studied was specific to a certain phase of the cell cycle, leading us to conclude that in nontransformed human T cells, both activation and apoptosis through T cell receptor activation can occur in all phases of the cell cycle.

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