scholarly journals ORP4L is a prerequisite for the induction of T-cell leukemogenesis associated with human T-cell leukemia virus 1

Blood ◽  
2021 ◽  
Author(s):  
Wenbin Zhong ◽  
Xiuye Cao ◽  
Guoping Pan ◽  
Qun Niu ◽  
Xiaoqin Feng ◽  
...  

Human T-cell leukemia virus 1 (HTLV-1) causes adult T-cell leukemia (ATL), but the mechanism underlying its initiation remains elusive. Here we report that ORP4L is expressed in ATL cells but not normal T-cells. ORP4L ablation completely blocks T-cell leukemogenesis induced by the HTLV-1 oncoprotein Tax in mice while engineering ORP4L expression in T-cells results in T-cell leukemia in mice, suggesting the oncogenic properties and prerequisite of ORP4L for the initiation of T-cell leukemogenesis. For molecular insight, loss of miR-31 caused by HTLV-1 induces ORP4L expression in T-cells. ORP4L interacts with PI3Kδ to promote PI(3,4,5)P3 generation, contributing to AKT hyperactivation, NF-κB-dependent p53 inactivation induced pro-oncogenes expression and T-cell leukemogenesis. Consistently, ORP4L ablation eliminates human ATL cells in patient-derived xenograft ATL models. These results reveal a plausible mechanism of T-cells deterioration by HTLV-1 that can be therapeutically targeted.

Blood ◽  
1995 ◽  
Vol 85 (7) ◽  
pp. 1865-1870 ◽  
Author(s):  
Y Furukawa ◽  
M Osame ◽  
R Kubota ◽  
M Tara ◽  
M Yoshida

Patients with human T-cell leukemia virus type-1 (HTLV-1)-associated myelopathy (HAM/TSP) generally harbor a much greater population of HTLV-1-infected T cells in peripheral blood mononuclear cells (PBMCs) than asymptomatic carriers. These cells are not malignant but frequently proliferate clonally. To investigate the possibility that higher expression of the viral activator Tax induces preferential proliferation of infected nonmalignant T cells in HAM/TSP patients, the expression of Tax mRNA in fresh PBMCs was analyzed by reverse transcriptase-mediated polymerase chain reaction. Total amount of Tax mRNA was higher in HAM/TSP patients than in carriers, but the expression level was almost the same as that in asymptomatic carriers when compared per infected cell. The expression levels in adult T-cell leukemia patients were significantly lower than those in HAM/TSP patients and asymptomatic carriers. These results indicate that tax gene is not expressed at a continuously high level in HAM/TSP patients who carry a high population of infected T cells, even in those with clonally proliferated infected T cells.


Blood ◽  
2002 ◽  
Vol 99 (5) ◽  
pp. 1505-1511 ◽  
Author(s):  
Osamu Yoshie ◽  
Ryuichi Fujisawa ◽  
Takashi Nakayama ◽  
Hitomi Harasawa ◽  
Hideaki Tago ◽  
...  

Chemokines and chemokine receptors play important roles in migration and tissue localization of various lymphocyte subsets. Here, we report the highly frequent expression of CCR4 in adult T-cell leukemia (ATL) and human T-cell leukemia virus type 1 (HTLV-1)–immortalized T cells. Flow cytometric analysis revealed that ATL and HTLV-1–immortalized T-cell lines consistently expressed CCR4. Inducible expression of HTLV-1 transcriptional activator tax in a human T-cell line Jurkat did not, however, up-regulate CCR4 mRNA. In vitro immortalization of peripheral blood T cells led to preferential outgrowth of CD4+ T cells expressing CCR4. We further demonstrated highly frequent expression of CCR4 in fresh ATL cells by (1) reverse transcriptase–polymerase chain reaction (RT-PCR) analysis of CCR4 expression in peripheral blood mononuclear cells (PBMCs) from patients with ATL and healthy controls; (2) flow cytometric analysis of CCR4-expressing cells in PBMCs from patients with ATL and healthy controls; (3) CCR4 staining of routine blood smears from patients with ATL; and (4) an efficient migration of fresh ATL cells to the CCR4 ligands, TARC/CCL17 and MDC/CCL22, in chemotaxis assays. Furthermore, we detected strong signals for CCR4, TARC, and MDC in ATL skin lesions by RT-PCR. Collectively, most ATL cases have apparently derived from CD4+ T cells expressing CCR4. It is now known that circulating CCR4+ T cells are mostly polarized to Th2 and also contain essentially all skin-seeking memory T cells. Thus, HTLV-1–infected CCR4+ T cells may have growth advantages by deviating host immune responses to Th2. CCR4 expression may also account for frequent infiltration of ATL into tissues such as skin and lymph nodes.


Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 127
Author(s):  
Norbert Kassay ◽  
János András Mótyán ◽  
Krisztina Matúz ◽  
Mária Golda ◽  
József Tőzsér

The human T-lymphotropic viruses (HTLVs) are causative agents of severe diseases including adult T-cell leukemia. Similar to human immunodeficiency viruses (HIVs), the viral protease (PR) plays a crucial role in the viral life-cycle via the processing of the viral polyproteins. Thus, it is a potential target of anti-retroviral therapies. In this study, we performed in vitro comparative analysis of human T-cell leukemia virus type 1, 2, and 3 (HTLV-1, -2, and -3) proteases. Amino acid preferences of S4 to S1′ subsites were studied by using a series of synthetic oligopeptide substrates representing the natural and modified cleavage site sequences of the proteases. Biochemical characteristics of the different PRs were also determined, including catalytic efficiencies and dependence of activity on pH, temperature, and ionic strength. We investigated the effects of different HIV-1 PR inhibitors (atazanavir, darunavir, DMP-323, indinavir, ritonavir, and saquinavir) on enzyme activities, and inhibitory potentials of IB-268 and IB-269 inhibitors that were previously designed against HTLV-1 PR. Comparative biochemical analysis of HTLV-1, -2, and -3 PRs may help understand the characteristic similarities and differences between these enzymes in order to estimate the potential of the appearance of drug-resistance against specific HTLV-1 PR inhibitors.


2016 ◽  
Vol 27 (9) ◽  
pp. 1059-1066 ◽  
Author(s):  
Hisayoshi Kondo ◽  
Midori Soda ◽  
Norie Sawada ◽  
Manami Inoue ◽  
Yoshitaka Imaizumi ◽  
...  

2006 ◽  
Vol 97 (9) ◽  
pp. 836-841 ◽  
Author(s):  
Takayuki Nitta ◽  
Masayuki Kanai ◽  
Eiji Sugihara ◽  
Masakazu Tanaka ◽  
Binlian Sun ◽  
...  

1986 ◽  
Vol 83 (12) ◽  
pp. 4524-4528 ◽  
Author(s):  
M. Shimoyama ◽  
Y. Kagami ◽  
K. Shimotohno ◽  
M. Miwa ◽  
K. Minato ◽  
...  

2003 ◽  
Vol 77 (14) ◽  
pp. 7728-7735 ◽  
Author(s):  
Jianxin Ye ◽  
Li Xie ◽  
Patrick L. Green

ABSTRACT Human T-cell leukemia virus type 1 (HTLV-1) and HTLV-2 are distinct oncogenic retroviruses that infect several cell types but display their biological and pathogenic activity only in T cells. Previous studies have indicated that in vivo HTLV-1 has a preferential tropism for CD4+ T cells, whereas HTLV-2 in vivo tropism is less clear but appears to favor CD8+ T cells. Both CD4+ and CD8+ T cells are susceptible to HTLV-1 and HTLV-2 infection in vitro, and HTLV-1 has a preferential immortalization and transformation tropism of CD4+ T cells, whereas HTLV-2 immortalizes and transforms primarily CD8+ T cells. The molecular mechanism that determines this tropism of HTLV-1 and HTLV-2 has not been determined. HTLV-1 and HTLV-2 carry the tax and rex transregulatory genes in separate but partially overlapping reading frames. Since Tax has been shown to be critical for cellular transformation in vitro and interacts with numerous cellular processes, we hypothesized that the viral determinant of transformation tropism is encoded by tax. Using molecular clones of HTLV-1 (Ach) and HTLV-2 (pH6neo), we constructed recombinants in which tax and overlapping rex genes of the two viruses were exchanged. p19 Gag expression from proviral clones transfected into 293T cells indicated that both recombinants contained functional Tax and Rex but with significantly altered activity compared to the wild-type clones. Stable transfectants expressing recombinant viruses were established, irradiated, and cocultured with peripheral blood mononuclear cells. Both recombinants were competent to transform T lymphocytes with an efficiency similar to that of the parental viruses. Flow cytometry analysis indicated that HTLV-1 and HTLV-1/TR2 had a preferential tropism for CD4+ T cells and that HTLV-2 and HTLV-2/TR1 had a preferential tropism for CD8+ T cells. Our results indicate that tax/rex in different genetic backgrounds display altered functional activity but ultimately do not contribute to the different in vitro transformation tropisms. This first study with recombinants between HTLV-1 and HTLV-2 is the initial step in elucidating the different pathobiologies of HTLV-1 and HTLV-2.


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