Expression of Human Inducible Nitric Oxide Synthase Gene in T-Cell Lines Infected With Human T-Cell Leukemia Virus Type-I and Primary Adult T-Cell Leukemia Cells

Blood ◽  
1999 ◽  
Vol 94 (8) ◽  
pp. 2862-2870 ◽  
Author(s):  
Naoki Mori ◽  
Youichi Nunokawa ◽  
Yasuaki Yamada ◽  
Shuichi Ikeda ◽  
Masao Tomonaga ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
Leukemic Cells ◽  
Type I ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Lines

We examined the expression of messenger RNA (mRNA) of the human inducible nitric oxide synthase (hiNOS) gene in a panel of human T-cell lines. Reverse transcriptase-polymerase chain reaction showed that human T-cell leukemia virus type-I (HTLV-I)–infected T-cell lines (MT-1, SLB-1, and C5/MJ) expressed mRNA for the hiNOS, but TL-Om1 or uninfected Jurkat, H9, and CCRF-CEM did not. The MT-1, SLB-1, and C5/MJ cell lines are infected with HTLV-I and express the viral transactivator Tax, whereas TL-Om1 cells, although derived from adult T-cell leukemia (ATL) leukemic cells, do not express Tax. There was, thus, a correlation between Tax and hiNOS mRNA expression. The transcriptional regulatory region of the hiNOS gene was activated by Tax in Jurkat, in which endogenous hiNOS is induced by Tax. Deletion analysis showed that the region of hiNOS encompassing nucleotides −159 to −111 contained the minimum Tax-responsive elements. Mutations in the NF-κB element at position −115 and −106 bp in the hiNOS promoter were still activated by Tax, and a Tax mutant defective for activation of the NF-κB pathway retained the ability to activate the hiNOS promoter. In addition, overexpression of the dominant-negative mutants of IκB and I κBβ failed to reduce Tax-induced activation of hiNOS gene. Furthermore, hiNOS mRNA was detected in leukemic cells from ATL patients. Our results show that the hiNOS promoter contains a minimum Tax-responsive element located between nucleotides −159 and −111, and imply that the expression of the hiNOS gene is involved in the pathogenesis of HTLV-I–associated diseases.

Human T-Cell Leukemia Virus Type I Tax Activates CD69 Gene Expression.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2256-2256
Author(s):  
Chie Ishikawa ◽  
Taeko Okudaira ◽  
Tetsuro Nakazato ◽  
Mariko Tomita ◽  
Naoki Mori
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
Type I ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
Cd69 Expression ◽  
T Cell Lines

Abstract The human T-cell leukemia virus type I (HTLV-I) is an oncogenic retrovirus that is etiologically linked to the genesis of adult T-cell leukemia (ATL). Emerging evidence suggests that the pathogenicity of ATL involves suppression of the overall immune response, although the underlying mechanism remains unclear. In this study, we demonstrated that HTLV-I transactivator Tax induces the aberrant expression of CD69, an early leukocyte activation molecule that plays an important role in downregulation of the immune response. In a panel of HTLV-I-infected T-cell lines, CD69 expression was highly elevated compared to HTLV-I-negative T-cell lines at both mRNA and protein levels. Furthermore, CD69 expression correlated with Tax expression. Peripheral blood mononuclear cells from ATL patients also showed an increased expression of CD69 compared with controls. In vitro infection of a T-cell line with HTLV-I was associated with CD69 expression in conjunction with the increasing Tax expression. Expression of CD69 was dependent upon Tax expression in the inducible Tax-expressing cell line JPX-9. Tax transactivated the CD69 gene promoter in a transient transfection assay. Using Tax mutants and dominant negative mutants of IκBs, IKKs, NIK, and CREB, we demonstrated that Tax-induced CD69 expression required the NF-κB and CREB signaling pathways. A series of deletion and mutation analyses of the CD69 gene promoter indicated that two NF-κB, two EGR, and a CRE sequences were critical for Tax transactivation. Electrophoretic mobility shift assay showed the formation of specific protein-DNA complexes in HTLV-I-infected T-cell lines. These results suggest that Tax directly transactivated CD69 gene expression, through multiple cis-acting elements and by the interplay of transcription factors of the NF-κB, EGR, and CREB families. Tax-induced CD69 expression may be involved in immune suppression in ATL.

scholarly journals Transcriptional regulation of the human interleukin-6 gene promoter in human T-cell leukemia virus type I-infected T-cell lines: evidence for the involvement of NF-kappa B

Blood ◽  
1994 ◽  
Vol 84 (9) ◽  
pp. 2904-2911 ◽  
Author(s):  
N Mori ◽  
F Shirakawa ◽  
H Shimizu ◽  
S Murakami ◽  
S Oda ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
Type I ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Nf Kappa B ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Lines

Abstract Freshly isolated leukemic cells from patients with adult T-cell leukemia (ATL) and human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines constitutively produce high levels of interleukin-6 (IL-6) protein and mRNA. To clarify the mechanisms that lead to the activation of IL-6 gene in HTLV-I-infected cells, we first studied the regulatory regions in the IL-6 gene transcription by transfection of chloramphenicol acetyltransferase (CAT) reporter plasmids containing the IL-6 promoter. When transfected into HTLV-I-infected T-cell lines MT-2 and HUT-102, IL-6 promoter/CAT plasmids were strongly activated without any stimulation. By deletion analysis of 52 upstream region of IL-6 promoter, the DNA region between -73 and -59 bp from the transcription start site of IL-6 gene was important in the expression of IL-6/CAT activities in HTLV-I-infected cells. This region contains nuclear factor (NF)-kappa B binding site. The site-directed mutation of the kappa B motif in IL-6/CAT plasmid resulted in the complete abrogation of IL-6 promoter activity in these cells. Furthermore, when IL-6 promoter/CAT plasmid was introduced into an HTLV-I-uninfected T- cell line, Jurkat, IL-6 promoter activity was silent in the basal level, but strongly increased by the cotransfection with an HTLV-I tax expression plasmid. However, tax expression plasmid showed no transactivation activity, when kappa B site was mutated in IL-6 promoter/CAT plasmid. We found that the IL-6 kappa B site specifically formed a complex with NF-kappa B-containing nuclear extracts from MT-2 and HUT-102 cells. Finally, transfection of HTLV-I tax into Jurkat cells resulted in induction of specific binding of nuclear extracts to the NF-kappa B sequence. These results strongly suggest that HTLV-I tax gene may transactivate IL-6 gene through kappa B site in HTLV-I- positive T-cell lines and activation of NF-kappa B may be crucial in HTLV-I-induced IL-6 gene activation in ATL.

scholarly journals Transcriptional regulation of the human interleukin-6 gene promoter in human T-cell leukemia virus type I-infected T-cell lines: evidence for the involvement of NF-kappa B

Blood ◽  
1994 ◽  
Vol 84 (9) ◽  
pp. 2904-2911 ◽  
Author(s):  
N Mori ◽  
F Shirakawa ◽  
H Shimizu ◽  
S Murakami ◽  
S Oda ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
Type I ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Nf Kappa B ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Lines

Freshly isolated leukemic cells from patients with adult T-cell leukemia (ATL) and human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines constitutively produce high levels of interleukin-6 (IL-6) protein and mRNA. To clarify the mechanisms that lead to the activation of IL-6 gene in HTLV-I-infected cells, we first studied the regulatory regions in the IL-6 gene transcription by transfection of chloramphenicol acetyltransferase (CAT) reporter plasmids containing the IL-6 promoter. When transfected into HTLV-I-infected T-cell lines MT-2 and HUT-102, IL-6 promoter/CAT plasmids were strongly activated without any stimulation. By deletion analysis of 52 upstream region of IL-6 promoter, the DNA region between -73 and -59 bp from the transcription start site of IL-6 gene was important in the expression of IL-6/CAT activities in HTLV-I-infected cells. This region contains nuclear factor (NF)-kappa B binding site. The site-directed mutation of the kappa B motif in IL-6/CAT plasmid resulted in the complete abrogation of IL-6 promoter activity in these cells. Furthermore, when IL-6 promoter/CAT plasmid was introduced into an HTLV-I-uninfected T- cell line, Jurkat, IL-6 promoter activity was silent in the basal level, but strongly increased by the cotransfection with an HTLV-I tax expression plasmid. However, tax expression plasmid showed no transactivation activity, when kappa B site was mutated in IL-6 promoter/CAT plasmid. We found that the IL-6 kappa B site specifically formed a complex with NF-kappa B-containing nuclear extracts from MT-2 and HUT-102 cells. Finally, transfection of HTLV-I tax into Jurkat cells resulted in induction of specific binding of nuclear extracts to the NF-kappa B sequence. These results strongly suggest that HTLV-I tax gene may transactivate IL-6 gene through kappa B site in HTLV-I- positive T-cell lines and activation of NF-kappa B may be crucial in HTLV-I-induced IL-6 gene activation in ATL.

Preferential selection of human T-cell leukemia virus type I provirus integration sites in leukemic versus carrier states

Blood ◽  
2005 ◽  
Vol 106 (3) ◽  
pp. 1048-1053 ◽  
Author(s):  
Keitarou Doi ◽  
Xiaolin Wu ◽  
Yuko Taniguchi ◽  
Jun-ichirou Yasunaga ◽  
Yorifumi Satou ◽  
...  
Keyword(s):  
T Cell ◽  
Leukemia Virus ◽  
Leukemic Cells ◽  
Viral Gene ◽  
Type I ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
Integration Sites

Abstract Human T-cell leukemia virus type I (HTLV-I) is a causative agent of neoplastic disease, adult T-cell leukemia (ATL). Although the encoding viral proteins play an important role in oncogenesis, the role of the HTLV-I proviral integration site remains unsolved. We determined the integration sites of HTLV-I proviruses in ATL cells and HTLV-I–infected cells in asymptomatic carriers. In carrier and ATL cells, HTLV-I provirus was integrated into the transcriptional unit at frequencies of 26.8% (15/56) and 33.9% (20/59), respectively, which were equivalent to the frequency calculated based on random integration (33.2%). In addition, HTLV-I provirus was prone to integration near the transcriptional start sites in leukemic cells (P = .006), and the transcriptional direction of the provirus was in accordance with that of integrated cellular genes in 70% of cases. More importantly, the integration sites in the carrier cells favored the alphoid repetitive sequences (11/56; 20%) whereas in leukemic cells they disfavored these sequences (2/59; 3.4%). Taken together, during natural course from carrier to onset of ATL, HTLV-I–infected cells with integration sites favorable for viral gene transcription are susceptible to malignant transformation due to increased viral gene expression.

scholarly journals Apoptosis Induced by the Histone Deacetylase Inhibitor FR901228 in Human T-Cell Leukemia Virus Type 1-Infected T-Cell Lines and Primary Adult T-Cell Leukemia Cells

2004 ◽  
Vol 78 (9) ◽  
pp. 4582-4590 ◽  
Author(s):  
Naoki Mori ◽  
Takehiro Matsuda ◽  
Masayuki Tadano ◽  
Takao Kinjo ◽  
Yasuaki Yamada ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Adult T Cell Leukemia ◽  
Human T Cell ◽  
Induced Apoptosis ◽  
T Cell Lines

ABSTRACT Inhibition of histone deacetylase (HDAC) activity induces growth arrest, differentiation, and, in certain cell types, apoptosis. FR901228, FK228, or depsipeptide, is an HDAC inhibitor effective in T-cell lymphomas. Adult T-cell leukemia (ATL) is caused by human T-cell leukemia virus type 1 (HTLV-1) and remains incurable. We examined whether FR901228 is effective for treatment of ATL by assessing its ability to induce apoptosis of HTLV-1-infected T-cell lines and primary leukemic cells from ATL patients. FR901228 induced apoptosis of Tax-expressing and -unexpressing HTLV-1-infected T-cell lines and selective apoptosis of primary ATL cells, especially those of patients with acute ATL. FR901228 also efficiently reduced the DNA binding of NF-κB and AP-1 in HTLV-1-infected T-cell lines and primary ATL cells and down-regulated the expression of Bcl-xL and cyclin D2, regulated by NF-κB. Although the viral protein Tax is an activator of NF-κB and AP-1, FR901228-induced apoptosis was not associated with reduced expression of Tax. In vivo use of FR901228 partly inhibited the growth of tumors of HTLV-1-infected T cells transplanted subcutaneously in SCID mice. Our results indicated that FR901228 could induce apoptosis of these cells and suppress the expression of NF-κB and AP-1 and suggest that FR901228 could be therapeutically effective in ATL.

scholarly journals Aberrant Activation of the Interleukin-2 Autocrine Loop through the Nuclear Factor of Activated T Cells by Nonleukemogenic Human T-Cell Leukemia Virus Type 2 but Not by Leukemogenic Type 1 Virus

2005 ◽  
Vol 79 (18) ◽  
pp. 11925-11934 ◽  
Author(s):  
Akiko Niinuma ◽  
Masaya Higuchi ◽  
Masahiko Takahashi ◽  
Masayasu Oie ◽  
Yuetsu Tanaka ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Activated T Cells ◽  
Cell Leukemia Virus Type ◽  
Autocrine Loop ◽  
Human T Cell ◽  
T Cell Lines

ABSTRACT Human T-cell leukemia virus type 1 (HTLV-1) but not HTLV-2 is associated with adult T-cell leukemia. We found that HTLV-2 Tax2 protein stimulated reporter gene expression regulated by the interleukin (IL)-2 promoter through the nuclear factor of activated T cells (NFAT) in a human T-cell line (Jurkat). However, the activity of HTLV-1 Tax1 was minimal in this system. T-cell lines immortalized by HTLV-2 but not HTLV-1 constitutively exhibited activated NFAT in the nucleus and constitutively expressed IL-2 mRNA. Cyclosporine A, an inhibitor of NFAT activation, abrogated the induction of IL-2 mRNA in HTLV-2-immortalized T-cell lines and concomitantly inhibited cell growth. This growth inhibition was rescued by the addition of IL-2 to the culture. Furthermore, anti-IL-2 receptor antibodies significantly reduced the proliferation of HTLV-2-infected T-cell lines but not that of HTLV-1-infected cells. Our results suggest that Tax2 activates an IL-2 autocrine loop mediated through NFAT that supports the growth of HTLV-2-infected cells under low-IL-2 conditions. This mechanism would be especially important in vivo, where this autocrine mechanism establishes a nonleukemogenic life-long HTLV-2 infection. The results also suggest that differences in long-term cytokine production between HTLV-1 and HTLV-2 infection are another factor for the differences in pathogenesis.

scholarly journals Resistance to Apo2 Ligand (Apo2L)/Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL)-Mediated Apoptosis and Constitutive Expression of Apo2L/TRAIL in Human T-Cell Leukemia Virus Type 1-Infected T-Cell Lines

2005 ◽  
Vol 79 (3) ◽  
pp. 1367-1378 ◽  
Author(s):  
Takehiro Matsuda ◽  
Alex Almasan ◽  
Mariko Tomita ◽  
Jun-nosuke Uchihara ◽  
Masato Masuda ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Leukemia Virus ◽  
Induced Apoptosis ◽  
T Cell Lines

ABSTRACT Adult T-cell leukemia (ATL), a CD4+-T-cell malignancy caused by human T-cell leukemia virus type 1 (HTLV-1), is difficult to cure, and novel treatments are urgently needed. Apo2 ligand (Apo2L; also tumor necrosis factor-related apoptosis-inducing ligand [TRAIL]) has been implicated in antitumor therapy. We found that HTLV-1-infected T-cell lines and primary ATL cells were more resistant to Apo2L-induced apoptosis than uninfected cells. Interestingly, HTLV-1-infected T-cell lines and primary ATL cells constitutively expressed Apo2L mRNA. Inducible expression of the viral oncoprotein Tax in a T-cell line up-regulated Apo2L mRNA. Analysis of the Apo2L promoter revealed that this gene is activated by Tax via the activation of NF-κB. The sensitivity to Apo2L was not correlated with expression levels of Apo2L receptors, intracellular regulators of apoptosis (FLICE-inhibitory protein and active Akt). NF-κB plays a crucial role in the pathogenesis and survival of ATL cells. The resistance to Apo2L-induced apoptosis was reversed by N-acetyl-l-leucinyl-l-leucinyl-l-norleucinal (LLnL), an NF-κB inhibitor. LLnL significantly induced the Apo2L receptors DR4 and DR5. Our results suggest that the constitutive activation of NF-κB is essential for Apo2L gene induction and protection against Apo2L-induced apoptosis and that suppression of NF-κB may be a useful adjunct in clinical use of Apo2L against ATL.

scholarly journals Constitutive expression of the cyclooxygenase-2 gene in T-cell lines infected with human T cell leukemia virus type I

2001 ◽  
Vol 94 (6) ◽  
pp. 813-819 ◽  
Author(s):  
Naoki Mori ◽  
Hiroyasu Inoue ◽  
Tsutomu Yoshida ◽  
Tadashi Tanabe ◽  
Naoki Yamamoto
Keyword(s):  
T Cell ◽  
Cell Lines ◽  
Leukemia Virus ◽  
Constitutive Expression ◽  
Type I ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
T Cell Leukemia Virus ◽  
T Cell Lines
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