Non-cytotoxic 1,2,3-triazole tethered fused heterocyclic ring derivatives display Tax protein inhibition and impair HTLV-1 infected cells

Abstract Abstract 1730 Human T-lymphotropic virus type-1(HTLV-1) is the causative agent of adult T cell leukemia/lymphoma (ATL). HTLV-1 infected T cell growth or leukemogenesis in ATL is controlled by various host immune surveillance systems. Among them, CD70 on HTLV-1 infected T cells coupled with CD27 on virus specific cytotoxic T cells has been suggested to play an important role in ATL leukemogenesis. The CD70 molecule is the only known ligand for CD27, a member of the tumor necrosis factor (TNF) receptor superfamily 7. This negative immunoregulatory pathway downregulates cytotoxic T lymphocyte activity against CD70-expressing virus infected cells. In the present study, we examined CD70 expression on primary lymphocytes of HTLV-1 carriers and ATL patients, its relationship with HTLV-1 Tax protein expression, and the effect on CTL induction. CD70 expression was higher on peripheral blood mononuclear cells (PBMCs) of HTLV-1 infected carriers compared with healthy donors (p = 0.021, n = 21, Mann-Whitney U test), and higher in ATL patients compared to carriers (p = 0.045, n = 38, Mann-Whitney U test). CD70 expression may be observed in CD4 T cells, as well as B cells, but not in CD8 T cells or monocytes. CD70 expression in CD4 T cells is related to HTLV-1 infection, because of increased detection of HTLV-1 Tax protein during over night culture of CD70-expressing cells. Experiments using an ATL cell line, in which Tax expression is inducible by doxycycline stimulation, demonstrated enhanced CD70 expression when Tax protein was induced in HTLV-1 infected cells. Anti-CD70 antibody enhanced CD107a mobilization, a marker of recent cytotoxic degranulation, in HTLV-1 Tax specific CTLs in PBMCs from asymptomatic carriers in vitro, suggesting that the CD70/CD27 pathway plays an important role in the immune response to HTLV-1 infection in carriers, as well as ATL patients. Disclosures: No relevant conflicts of interest to declare.

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Bromodomain and Extraterminal (BET) Protein Inhibition Suppresses Human T Cell Leukemia Virus 1 (HTLV-1) Tax Protein-mediated Tumorigenesis by Inhibiting Nuclear Factor κB (NF-κB) Signaling

Journal of Biological Chemistry ◽

10.1074/jbc.m113.485029 ◽

2013 ◽

Vol 288 (50) ◽

pp. 36094-36105 ◽

Cited By ~ 26

Author(s):

Xuewei Wu ◽

Jun Qi ◽

James E. Bradner ◽

Gutian Xiao ◽

Lin-Feng Chen

Keyword(s):

T Cell ◽

Leukemia Virus ◽

Nuclear Factor Κb ◽

Nuclear Factor ◽

Cell Leukemia ◽

Protein Inhibition ◽

Tax Protein ◽

Human T Cell ◽

T Cell Leukemia Virus ◽

Bet Protein

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Inhibition of Caspase Cascade by HTLV-I Tax Through Induction of NF-κB Nuclear Translocation

Blood ◽

10.1182/blood.v94.11.3847.423a24_3847_3854 ◽

1999 ◽

Vol 94 (11) ◽

pp. 3847-3854 ◽

Cited By ~ 3

Author(s):

Atsushi Kawakami ◽

Tomoki Nakashima ◽

Hideaki Sakai ◽

Satoshi Urayama ◽

Satoshi Yamasaki ◽

...

Keyword(s):

Nuclear Translocation ◽

Leukemia Virus ◽

Plasmid Vector ◽

Jurkat Cells ◽

Tax Protein ◽

Human T Cell ◽

T Cell Leukemia Virus ◽

Infected Cells ◽

Sequential Activation ◽

Caspase Cascade

NF-κB is required for prevention of apoptosis. We examined the importance of human T-cell leukemia virus–I (HTLV-I) Tax protein to stimulate NF-κB nuclear translocation, thus preventing apoptosis. Jurkat cells and JPX-9 cells in which the inducible Tax expression plasmid vector was stably transfected were used in the present study. Both Jurkat and Tax− JPX-9 cells had small amounts of basal nuclear NF-κB activity. The addition of NF-κB inhibitors suppressed NF-κB nuclear translocation of the cells, thus inducing apoptosis. Sequential activation of caspases from caspase-8 to caspase-3 was shown during this process. NF-κB nuclear translocation in JPX-9 cells was stimulated through Tax expression, and both the activation of caspases and apoptosis induced by NF-κB inhibitors were significantly suppressed in the Tax+ JPX-9 cells. The expression of Bcl-2, Bax, and Bcl-x was not changed among Jurkat, Tax− JPX-9, and Tax+ JPX-9 cells in the presence or absence of NF-κB inhibitors. X-chromosome–linked inhibitor of apoptosis (XIAP) protein expression in Tax−JPX-9 cells was significantly suppressed by NF-κB inhibitors, however, its expression in Tax+ JPX-9 cells was maintained even by the addition of NF-κB inhibitors. Our results suggest that the activation of NF-κB via Tax protein in HTLV-I infected cells renders the cells resistant to apoptosis. The expression of anti-apoptotic gene products such as XIAP to suppress caspase cascade, results in an increase of cytokine production and cell proliferation; one of the proposed mechanisms that promotes autoimmune disorders such as Sjögren’s syndrome and rheumatoid arthritis found in HTLV-I seropositive subjects.

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Inhibition of Caspase Cascade by HTLV-I Tax Through Induction of NF-κB Nuclear Translocation

Blood ◽

10.1182/blood.v94.11.3847 ◽

1999 ◽

Vol 94 (11) ◽

pp. 3847-3854 ◽

Cited By ~ 58

Author(s):

Atsushi Kawakami ◽

Tomoki Nakashima ◽

Hideaki Sakai ◽

Satoshi Urayama ◽

Satoshi Yamasaki ◽

...

Keyword(s):

Nuclear Translocation ◽

Leukemia Virus ◽

Plasmid Vector ◽

Jurkat Cells ◽

Tax Protein ◽

Human T Cell ◽

T Cell Leukemia Virus ◽

Infected Cells ◽

Sequential Activation ◽

Caspase Cascade

Abstract NF-κB is required for prevention of apoptosis. We examined the importance of human T-cell leukemia virus–I (HTLV-I) Tax protein to stimulate NF-κB nuclear translocation, thus preventing apoptosis. Jurkat cells and JPX-9 cells in which the inducible Tax expression plasmid vector was stably transfected were used in the present study. Both Jurkat and Tax− JPX-9 cells had small amounts of basal nuclear NF-κB activity. The addition of NF-κB inhibitors suppressed NF-κB nuclear translocation of the cells, thus inducing apoptosis. Sequential activation of caspases from caspase-8 to caspase-3 was shown during this process. NF-κB nuclear translocation in JPX-9 cells was stimulated through Tax expression, and both the activation of caspases and apoptosis induced by NF-κB inhibitors were significantly suppressed in the Tax+ JPX-9 cells. The expression of Bcl-2, Bax, and Bcl-x was not changed among Jurkat, Tax− JPX-9, and Tax+ JPX-9 cells in the presence or absence of NF-κB inhibitors. X-chromosome–linked inhibitor of apoptosis (XIAP) protein expression in Tax−JPX-9 cells was significantly suppressed by NF-κB inhibitors, however, its expression in Tax+ JPX-9 cells was maintained even by the addition of NF-κB inhibitors. Our results suggest that the activation of NF-κB via Tax protein in HTLV-I infected cells renders the cells resistant to apoptosis. The expression of anti-apoptotic gene products such as XIAP to suppress caspase cascade, results in an increase of cytokine production and cell proliferation; one of the proposed mechanisms that promotes autoimmune disorders such as Sjögren’s syndrome and rheumatoid arthritis found in HTLV-I seropositive subjects.

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Analysis of Nucleotide Sequence of Tax, miRNA and LTR of Bovine Leukemia Virus in Cattle with Different Levels of Persistent Lymphocytosis in Russia

Pathogens ◽

10.3390/pathogens10020246 ◽

2021 ◽

Vol 10 (2) ◽

pp. 246

Author(s):

Aneta Pluta ◽

Natalia V. Blazhko ◽

Charity Ngirande ◽

Thomas Joris ◽

Luc Willems ◽

...

Keyword(s):

Bovine Leukemia Virus ◽

Sequence Variation ◽

Leukemia Virus ◽

Lymphoproliferative Disease ◽

P Value ◽

Persistent Lymphocytosis ◽

Tax Protein ◽

Infected Cells ◽

The Relationship ◽

Bovine Species

Bovine Leukemia Virus (BLV) is the etiological agent of enzootic bovine leucosis (EBL), a lymphoproliferative disease of the bovine species. In BLV-infected cells, the long terminal repeat (LTR), the viral Tax protein and viral miRNAs promote viral and cell proliferation as well as tumorigenesis. Although their respective roles are decisive in BLV biology, little is known about the genetic sequence variation of these parts of the BLV genome and their impact on disease outcome. Therefore, the objective of this study was to assess the relationship between disease progression and sequence variation of the BLV Tax, miRNA and LTR regions in infected animals displaying either low or high levels of persistent lymphocytosis (PL). A statistically significant association was observed between the A(+187)C polymorphism in the downstream activator sequence (DAS) region in LTR (p-value = 0.00737) and high lymphocytosis. Our study also showed that the mutation A(−4)G in the CAP site occurred in 70% of isolates with low PL and was not found in the high PL group. Conversely, the mutations G(−133)A/C in CRE2 (46.7%), C(+160)T in DAS (30%) and A(310)del in BLV-mir-B4-5p, A(357)G in BLV-mir-B4-3p, A(462)G in BLV-mir-B5-5p, and GA(497–498)AG in BLV-mir-B5-3p (26.5%) were often seen in isolates with high PL and did not occur in the low PL group. In conclusion, we found several significant polymorphisms among BLV genomic sequences in Russia that would explain a progression towards higher or lower lymphoproliferation. The data presented in this article enabled the classification between two different genotypes; however, clear association between genotypes and the PL development was not found.

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Transcriptional activation of human TR3/nur77 gene expression by human T-lymphotropic virus type I Tax protein through two AP-1-like elements

Journal of General Virology ◽

10.1099/0022-1317-80-12-3073 ◽

1999 ◽

Vol 80 (12) ◽

pp. 3073-3081 ◽

Cited By ~ 17

Author(s):

Xiangdong Liu ◽

Xiaolin Chen ◽

Vladimir Zachar ◽

Chawnshang Chang ◽

Peter Ebbesen

Keyword(s):

Transcription Factor ◽

Virus Type ◽

Transcriptional Activation ◽

Gene Deletion ◽

Type I ◽

Transcription Start ◽

T Lymphotropic Virus ◽

Tax Protein ◽

Infected Cells ◽

Mutation Analyses

The Tax transactivator of human T-lymphotropic virus type I (HTLV-I) is capable of inducing expression of the human immediate-early TR3/nur77 gene. Deletion and mutation analyses of the TR3/nur77 promoter demonstrated that multiple transcription elements in the 121 bp sequence proximal to the transcription start site are required for full Tax transactivation. Mutations of CArG-like, Ets and RCE motifs in this region severely decreased Tax transactivation. Mutation of either of the two identical AP-1-like elements (NAP 1 and 2) immediately upstream of the TATA box caused around 80% reduction of Tax transactivation. Mutation of both NAP elements blocked Tax-mediated activation totally. These two NAP elements could confer Tax-responsiveness on a heterologous basal promoter. Furthermore, the specific NAP-binding complex was only observed in HTLV-I-infected cells. Formation of this specific NAP-binding complex was correlated directly with Tax expression, as demonstrated in JPX-9 cells upon induction of Tax expression. The specific NAP binding could be competed for by consensus AP-1 and CREB elements, indicating that the NAP-binding proteins probably belong to the AP-1 and CREB/ATF transcription factor families. Supershift analysis with antibodies to both the AP-1 and CREB/ATF transcription factor families revealed that only anti-JunD antibody could partially shift this NAP-binding complex, indicating that JunD is a component of the NAP complex. This work suggests that JunD is involved in Tax-regulated TR3/nur77 expression.

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Differential expression of Rel family members in human T-cell leukemia virus type I-infected cells: transcriptional activation of c-rel by Tax protein.

Journal of Virology ◽

10.1128/jvi.67.7.4205-4213.1993 ◽

1993 ◽

Vol 67 (7) ◽

pp. 4205-4213 ◽

Cited By ~ 17

Author(s):

C C Li ◽

F W Ruscetti ◽

N R Rice ◽

E Chen ◽

N S Yang ◽

...

Keyword(s):

T Cell ◽

Transcriptional Activation ◽

Leukemia Virus ◽

Type I ◽

Cell Leukemia ◽

Cell Leukemia Virus Type ◽

Tax Protein ◽

Human T Cell ◽

T Cell Leukemia Virus ◽

Infected Cells

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Interference with glycosylation of glycoproteins. Inhibition of formation of lipid-linked oligosaccharides in vivo

Biochemical Journal ◽

10.1042/bj1840113 ◽

1979 ◽

Vol 184 (1) ◽

pp. 113-123 ◽

Cited By ~ 80

Author(s):

R Datema ◽

R T Schwarz

Keyword(s):

Molecular Weight ◽

Influenza Virus ◽

Kinetic Analysis ◽

Protein Glycosylation ◽

Protein Inhibition ◽

Infected Cells ◽

Lag Period ◽

High Mannose ◽

Virus Proteins

Influenza-virus-infected cells were labelled with radioactive sugars and extracted to give fractions containing lipid-linked oligosaccharides and glycoproteins. The oligosaccharides linked to lipid were of the ‘high-mannose’ type and contained glucose. In the glycoprotein fraction, radioactivity was associated with virus proteins and found to occur predominantly in the ‘high-mannose’ type of glycopeptides. In the presence of the inhibitors 2-deoxy-D-glucose, 2-deoxy-2-amino-D-glucose (glucosamine), 2-deoxy-2-fluoro-D-glucose and 2-deoxy-2-fluoro-D-mannose incorporation of radiolabelled sugars into lipid- and protein-linked oligosaccharides was decreased. Kinetic analysis showed that the inhibitors affected first the assembly of lipid-linked oligosaccharides and then protein glycosylation after a lag period. During inhibition by deoxyglucose and the fluoro sugars lipid-linked oligosaccharides were formed that contained oligosaccharides of decreased molecular weight. No such aberrant forms were found during inhibition by glucosamine. In the case of inhibition by deoxyglucose it was shown that the aberrant oligosaccharides were not transferred to protein. Inhibition of formation of lipid-linked oligosaccharides by deoxyglucose and fluoro sugars was antagonized by mannose, in which case oligosaccharides of normal molecular weight were formed. The inhibition by glucosamine was reversed by its removal from the medium. The reversible effects of these inhibitors exemplify their usefulness as tools in the study of glycosylation processes.

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