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1.
Retrovirology ; 16(1): 5, 2019 02 19.
Article in English | MEDLINE | ID: mdl-30782173

ABSTRACT

BACKGROUND: Adult T-cell leukemia (ATL) is an aggressive neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1). ATL carries a poor prognosis due to chemotherapy resistance. Thus, it is urgent to develop new treatment strategies. Hypericin (HY) is a new-type of photosensitizer in the context of photodynamic therapy (PDT) due to its excellent photosensitizing properties and anti-tumor activities. RESULTS: In the present study, we investigated the efficacy of hypericin in ATL cells. Clinically achievable concentrations of hypericin in association with PDT induced the inhibition of cell proliferation in ATL cell lines with minimal effect on peripheral blood CD4+ T lymphocytes. Moreover, hypericin-PDT treatment caused apoptosis and G2/M phase cell cycle arrest in leukemic cells. Western blot analyses revealed that hypericin-PDT treatment resulted in downregulation of Bcl-2 and enhanced the expression of Bad, cytochrome C, and AIF. Cleavage of caspases-3/-7/-9/-8, Bid, and PARP was increased in hypericin-PDT-treated ATL cells. In a luciferase assay, hypericin-PDT treatment was able to activate the promoter activity of Bax and p53, resulting in enhanced expression of Bax and p53 proteins. Finally, hypericin-PDT treatment suppressed the expression of viral protein HBZ and Tax by blocking the promoter activity via HTLV-1 5'LTR and 3'LTR. CONCLUSIONS: Our results revealed that hypericin-PDT is highly effective against ATL cells by induction of apoptosis and suppression of viral transcription. These studies highlight the promising use of hypericin-PDT as a targeted therapy for ATL.


Subject(s)
Apoptosis/drug effects , Human T-lymphotropic virus 1/drug effects , Leukemia-Lymphoma, Adult T-Cell/drug therapy , Light , Perylene/analogs & derivatives , Photochemotherapy/methods , Photosensitizing Agents/pharmacology , Anthracenes , Apoptosis/radiation effects , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Proliferation/radiation effects , Cell Survival/drug effects , Cell Survival/radiation effects , Human T-lymphotropic virus 1/radiation effects , Humans , Models, Biological , Perylene/pharmacology , Transcription, Genetic/drug effects , Transcription, Genetic/radiation effects , Tumor Stem Cell Assay
2.
J Biosci ; 43(4): 785-795, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30207322

ABSTRACT

The human T-cell lymphotropic virus type 1 (HTLV-1) is a deltaretrovirus claimed to be aetiologically linked to the adult T-cell leukaemia/lymphoma (ATLL) and associated myelopathy/tropical spastic paraparesis (HAM/TSP) besides other minor pathologies. HTLV-1 infection is worldwide distributed, despite its heterogeneous prevalence. Environmental factors and host-genetic background are very likely to determine the epidemiological profile of HTLV-1 prevalence and related disease confinement in distinct human ethnic populations and geographical coordinates, which raises the question if the virus is a real pathogen or a runaway well-organized packed genome of a burden host cell near death process. New methodological approaches need to be proposed and applied in order to prove or discard the hypotheses emerged in the present review.


Subject(s)
HTLV-I Infections/virology , Human T-lymphotropic virus 1/pathogenicity , Leukemia-Lymphoma, Adult T-Cell/virology , Paraparesis, Tropical Spastic/virology , HTLV-I Infections/epidemiology , HTLV-I Infections/genetics , Human T-lymphotropic virus 1/genetics , Human T-lymphotropic virus 1/radiation effects , Humans , Leukemia-Lymphoma, Adult T-Cell/epidemiology , Leukemia-Lymphoma, Adult T-Cell/genetics , Paraparesis, Tropical Spastic/epidemiology , Paraparesis, Tropical Spastic/genetics , Radiation, Ionizing
3.
Viruses ; 8(7)2016 07 11.
Article in English | MEDLINE | ID: mdl-27409630

ABSTRACT

The environmental factors that lead to the reactivation of human T cell leukemia virus type-1 (HTLV-I) in latently infected T cells in vivo remain unknown. It has been previously shown that heat shock (HS) is a potent inducer of HTLV-I viral protein expression in long-term cultured cell lines. However, the precise HTLV-I protein(s) and mechanisms by which HS induces its effect remain ill-defined. We initiated these studies by first monitoring the levels of the trans-activator (Tax) protein induced by exposure of the HTLV-I infected cell line to HS. HS treatment at 43 °C for 30 min for 24 h led to marked increases in the level of Tax antigen expression in all HTLV-I-infected T cell lines tested including a number of HTLV-I-naturally infected T cell lines. HS also increased the expression of functional HTLV-I envelope gp46 antigen, as shown by increased syncytium formation activity. Interestingly, the enhancing effect of HS was partially inhibited by the addition of the heat shock protein 70 (HSP70)-inhibitor pifithlin-µ (PFT). In contrast, the HSP 70-inducer zerumbone (ZER) enhanced Tax expression in the absence of HS. These data suggest that HSP 70 is at least partially involved in HS-mediated stimulation of Tax expression. As expected, HS resulted in enhanced expression of the Tax-inducible host antigens, such as CD83 and OX40. Finally, we confirmed that HS enhanced the levels of Tax and gp46 antigen expression in primary human CD4⁺ T cells isolated from HTLV-I-infected humanized NOD/SCID/γc null (NOG) mice and HTLV-I carriers. In summary, the data presented herein indicate that HS is one of the environmental factors involved in the reactivation of HTLV-I in vivo via enhanced Tax expression, which may favor HTLV-I expansion in vivo.


Subject(s)
Gene Expression/radiation effects , Gene Products, tax/biosynthesis , Hot Temperature , Human T-lymphotropic virus 1/radiation effects , T-Lymphocytes/radiation effects , T-Lymphocytes/virology , Animals , Cells, Cultured , Disease Models, Animal , HTLV-I Infections/virology , Humans , Mice , Mice, Inbred NOD , Mice, SCID
4.
Tropical Doctor ; 44(2): 103-105, April 2014.
Article in English | MedCarib | ID: med-18216

ABSTRACT

The ophthalmic presentation of relapse in a patient with human T-lymphotropic virus type 1 (HTLV1) associated adult T-cell lymphoma leukaemia is described. Epidemiology, clinical features and therapeutic options are briefly reviewed. Antenatal screening and inclusion of HTLV1 in the differential diagnosis of inflammatory and neuromuscular eye conditions should be considered in endemic regions.


Subject(s)
Human T-lymphotropic virus 1/drug effects , Human T-lymphotropic virus 1/radiation effects , Trinidad and Tobago
5.
J Gen Virol ; 93(Pt 3): 608-617, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22113012

ABSTRACT

The biological properties of human T-cell leukemia virus type I (HTLV-I) and HTLV type II (HTLV-II) are not well elucidated as cell-free viruses. We established new assay systems to detect the infectivity of cell-free HTLVs and examined the stability of cell-free HTLVs at different temperatures. HTLVs lost infectivity more rapidly than did bovine leukemia virus (BLV), which is genetically related to HTLVs. The half-lives of three HTLV-I strains (two cosmopolitan strains and one Melanesian strain) at 37 °C were approximately 0.6 h, whereas the half-life of a BLV strain was 8.5 h. HTLV-I rapidly lost infectivity unexpectedly at 0 and 4 °C. We examined the stability of vesicular stomatitis virus pseudotypes with HTLV-I, HTLV-II or BLV Env proteins, and the Env proteins of HTLVs were found to be more unstable at 4 and 25 °C than the Env proteins of the BLV. Over the course of the viral life cycle, heat treatment inhibited HTLV-I infection at the phase of attachment to the host cells, and inhibition was more marked upon entry into the cells. The HTLV-I Env surface (SU) protein (gp46) was easily released from virions during incubation at 37 °C. However, this release was inhibited by pre-treatment of the virions with N-ethylmaleimide, suggesting that the inter-subunit bond between gp46 SU and gp21 transmembrane (TM) proteins is rearranged by disulfide bond isomerization. HTLVs are highly unstable over a wide range of temperatures because the disulfide bonds between the SU and TM proteins are labile.


Subject(s)
Human T-lymphotropic virus 1/radiation effects , Human T-lymphotropic virus 2/radiation effects , Microbial Viability/radiation effects , Disulfides/chemistry , Human T-lymphotropic virus 1/pathogenicity , Human T-lymphotropic virus 2/pathogenicity , Humans , Leukemia Virus, Bovine/pathogenicity , Leukemia Virus, Bovine/radiation effects , Protein Stability , Protein Subunits/chemistry , Temperature , Time Factors , Viral Envelope Proteins/chemistry
6.
Transfusion ; 45(7): 1151-9, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15987361

ABSTRACT

BACKGROUND: Human T-cell leukemia virus Types I and II (HTLV-I and HTLV-II), blood-borne retroviruses found worldwide, can cause leukemia, immunosuppression, and severe neurologic diseases. In most countries, HTLV-I and -II screening is not performed systematically for blood donations. A new photochemical treatment (PCT) with a synthetic psoralen was developed to inactivate most pathogens in platelet (PLT) concentrates or plasma and to improve the safety of blood donations. STUDY DESIGN AND METHODS: Cell-associated HTLV-I or -II (10(6)/mL) was inoculated in full-size fresh PLT concentrates or fresh frozen plasma and treated with 150 micromol per L amotosalen (S-59) and different doses of long-wavelength ultraviolet A (UVA) light. The residual viral titer in the treated samples was assessed by a cocultivation assay on indicator cells. RESULTS: The inactivation obtained at a 3.0 J per cm2 UVA dose was greater than 5.2 log foci-forming units (FFUs) per mL for HTLV-I and 4.6 log FFUs per mL for HTLV-II in presence of human PLT concentrates and greater than 4.5 log FFUs per mL for HTLV-I and 5.7 log FFUs per mL for HTLV-II in the presence of human plasma. The residual infectivity was very low and shown as the limit of detection of the cocultivation assay. CONCLUSION: In human plasma or PLT concentrates, the retroviruses HTLV-I and -II were strongly sensitive to the PCT with 150 micromol per L amotosalen (S-59) and a 3.0 J per cm2 UVA dose. This high efficiency for photoinactivation of these retroviruses opens a possibility of improving the safety of PLTs or plasma transfusion in the future.


Subject(s)
Blood Platelets/virology , Human T-lymphotropic virus 1/growth & development , Human T-lymphotropic virus 2/growth & development , Plasma/virology , Ultraviolet Rays , Furocoumarins/pharmacology , Human T-lymphotropic virus 1/drug effects , Human T-lymphotropic virus 1/radiation effects , Human T-lymphotropic virus 2/drug effects , Human T-lymphotropic virus 2/radiation effects , Humans , Platelet Transfusion/adverse effects , Virus Replication/drug effects , Virus Replication/radiation effects
7.
J Gen Virol ; 85(Pt 8): 2397-2406, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15269382

ABSTRACT

The biological characteristics of human T-cell leukaemia virus type I (HTLV-I) are not yet well understood. UV light C (UV-C) sensitivity of HTLV-I was studied using a newly established infectivity assay: infection with cell-free HTLV-I dose-dependently induced syncytial plaques in cat cells transduced with the tax1 gene of HTLV-I. HTLV-I was inactivated by a much lower UV dose than bovine leukaemia virus (BLV). The D(10) (10 % survival dose) of HTLV-I was about 20 J m(-2), while that of BLV was about 180 J m(-2), which was similar to the reported D(10) of BLV. The UV sensitivity of HTLV-I and BLV was also examined by detecting viral DNA synthesis 24 h after infection. The D(10) values determined by PCR using the gag primers for HTLV-I and BLV were close to those determined by the infectivity assays. Further PCR analyses were then performed to determine D(10) values using several different primers located between the 5'-long terminal repeat (5'-LTR) and the tax1 gene. The difference in UV sensitivity between HTLV-I and BLV was detected very early during replication, even during reverse transcription of the 5'-LTR of irradiated viruses, and became more prominent as reverse transcription proceeded towards the tax1 gene. Chimeric mouse retroviruses that contain the LTR-tax1 fragments of HTLV-I and BLV were made and hardly any difference in UV sensitivity was detected between them, suggesting that the difference was not determined by the linear RNA sequences of HTLV-I and BLV. HTLV-I was found to be much more sensitive than other retroviruses to UV.


Subject(s)
Human T-lymphotropic virus 1/radiation effects , Ultraviolet Rays , DNA, Viral/biosynthesis , HeLa Cells , Human T-lymphotropic virus 1/genetics , Humans , Leukemia Virus, Bovine/radiation effects , RNA, Viral/radiation effects , Radiation Tolerance , Transcription, Genetic , Vesicular stomatitis Indiana virus/radiation effects
8.
Blood ; 86(11): 4063-75, Dec.1 1995.
Article in English | MedCarib | ID: med-1757

ABSTRACT

Adult T-cell leukemia (ATL) is a malignancy of mature lumphocytes caused by the retrovirus human T-cell lymphotropic virus-I. It is an aggressive leukemia with a median survival time of 9 months: no chemotherapy regimen appears successful inducing long-term disease-free survival. The scientific basis of the present study is the ATL cells express high-affinity interleukin-2 receptors identified by the anti-Tac monoclonal antibody, whereas normal resting cells do not. To exploit this differnce, we administered anti-Tac armed with Yttrium-90 (Y) to 18 patients with ATL initially (first 9 patients) in a phase I dose-escalation trial and subsequently (second group of 9 patients) in a phase II trial involving a uniform 10-mCi dose of Y-labeled anti-Tac. Patients undergoing a remission were permitted to receive up to eight additional doses. At the 5-to 15-mCi doses used, 9 of 16 evaluable patients responded to Y anti-Tac with a partial (7 patients) or complete (2 patients) remission. The responses observed represent improved efficacy in terms of length of remission when compared with previous results with unmodified anti-Tac. Clinically meaningful (> grade 3) toxicity was largely limited to the hematopoietic system. In conclusion, radioimmunotherapy with Y anti-Tac directed toward the IL-2R expressed on ATL cells may provide a useful approach for treatment of this aggressive malignancy.(AU)


Subject(s)
Adult , Middle Aged , Aged , Female , Humans , Male , Human T-lymphotropic virus 1/radiation effects , Receptors, Interleukin-2/therapeutic use , Radioimmunotherapy , Yttrium Radioisotopes/therapeutic use , Antibodies, Monoclonal/therapeutic use , United States , Jamaica , Trinidad and Tobago , Guyana , Japan , Haiti , Grenada , Saint Vincent and the Grenadines , Cross-Sectional Studies
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