Human Adult T-cell Leukemia Research Articles

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

AbstractHuman T-cell leukemia virus 1 (HTLV-1) causes adult T-cell leukemia (ATL), but the mechanism underlying its initiation remains elusive. In this study, ORP4L was expressed in ATL cells but not in normal T-cells. ORP4L ablation completely blocked T-cell leukemogenesis induced by the HTLV-1 oncoprotein Tax in mice, whereas engineering ORP4L expression in T-cells resulted in T-cell leukemia in mice, suggesting the oncogenic properties and prerequisite of ORP4L promote the initiation of T-cell leukemogenesis. For molecular insight, we found that loss of miR-31 caused by HTLV-1 induced 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-oncogene 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-cell deterioration by HTLV-1 that can be therapeutically targeted.

IL-2 and IL-15 blockade by BNZ-1, an inhibitor of selective γ-chain cytokines, decreases leukemic T-cell viability.

Interleukin-15 (IL-15) and IL-2 drive T-cell malignancies including T-cell large granular lymphocyte leukemia (T-LGLL) and HTLV-1 driven adult T-cell leukemia (ATL). Both cytokines share common γ-chain receptors and downstream signaling pathways. T-LGLL is characterized by clonal expansion of cytotoxic T cells and is associated with abnormal JAK/STAT signaling. ATL is an aggressive CD4+ T cell neoplasm associated with HTLV-1. T-LGLL and ATL share dependence on IL-2 and IL-15 for survival and both diseases lack effective therapies. BNZ-1 is a pegylated peptide designed to specifically bind the γc receptor to selectively block IL-2, IL-15 and IL-9 signaling. We hypothesized that treatment with BNZ-1 would reduce cytokine mediated proliferation and viability. Our results demonstrated that in vitro treatment of a T-LGLL cell line and ex vivo treatment of T-LGLL patient cells with BNZ-1 inhibited cytokine mediated viability. Furthermore, BNZ-1 blocked downstream signaling and increased apoptosis. These results were mirrored in an ATL cell line and in ex vivo ATL patient cells. Lastly, BNZ-1 drastically reduced leukemic burden in an IL-15-driven human ATL mouse xenograft model. Thus, BNZ-1 shows great promise as a novel therapy for T-LGLL, ATL and other IL-2 or IL-15 driven hematopoietic malignancies.

Cytopathologic Herpes Simplex Virus Features In Laryngeal Squamous Cell Carcinoma

Cytopathologic Herpes Simplex Virus Features In Laryngeal Squamous Cell Carcinoma

ID: 238: IL-15 markedly augmented the number of circulating NK cells and enhanced ADCC mediated by tumor-directed monoclonal antibodies

Interleukin-15, that activates antitumor T and natural killer cells, has potential applications in cancer immunotherapy. IL-15 administered at 20 μg/kg/day by continuous intravenous (CIV) infusion for 10 days to nonhuman primates yielded an 80–100-fold expansion of circulating CD8+ effector memory T-cells, a 15-fold increase in the number of monocytes and an 8-fold increase in NK cells. Based on these observations we performed a first-in-human phase 1 clinical trial of rhIL-15 administered by bolus infusions and a trial of IL-15 by CIV in patients with metastatic malignancy. When administered by CIV at 2 μg/kg per day IL-15 led to a 30-fold increase in the number of NK cells and over a 200-fold increase in the number of CD56+ CD16− NK cells. It was clear from these clinical trials that to be effective IL-15 would have to be administered in combination with agents with specificity directed toward the tumor. Given the capacity of IL-15 to increase NK cells an attractive strategy was to use it in conjunction with an antitumor antibody to augment ADCC. When IL-15 was administered with rituximab it markedly increased the ADCC effectiveness of this antibody in a syngeneic mouse model of human B-cell lymphoma involving EL4 leukemia cells transfected with human CD20. Activity of this combination was lost in Fc alpha-R-1- mice. Furthermore IL-15 augmented the ADCC of alemtuzumab in a xenograft model of human adult T-cell leukemia (ATL). These studies support our clinical trial involving IL-15 with alemtuzumab in patients with acute ATL.

Augmented efficacy with the combination of blockade of the Notch-1 pathway, bortezomib and romidepsin in a murine MT-1 adult T-cell leukemia model.

Adult T-cell leukemia (ATL) is an aggressive malignancy caused by human T-cell lymphotropic virus I (HTLV-1). There is no accepted curative therapy for ATL. We have reported that certain ATL patients have increased Notch-1 signaling along with constitutive activation of the NF-κB pathway. Physical and functional interaction between these two pathways provides the rationale to combine the γ-secretase inhibitor Compound E with the proteasome inhibitor Bortezomib. Moreover, Romidepsin, a histone deacetylase inhibitor, has demonstrated major antitumor action in leukemia/lymphoma. In this study, we investigated the therapeutic efficacy of the single agents and combinations of these agents in a murine model of human ATL, the MT-1 model. Single and double agents inhibited tumor growth as monitored by tumor size (P < .05), and prolonged survival of leukemia-bearing mice (P < .05) compared with the control group. The combination of three agents significantly enhanced the antitumor efficacy as assessed by tumor size, tumor markers in the serum (human sIL-2Rα and β2M), and survival of the MT-1 tumor bearing mice, compared with all other treatment groups (P < .05). Improved therapeutic efficacy obtained by combining Compound E, Bortezomib and Romidepsin supports a clinical trial of this combination in the treatment of ATL.

Evidence of the Human T-cell Lymphotropic Virus (HTLV-I) Circulation in Santiago De Cuba Province (Cuba)

Evidence of the Human T-cell Lymphotropic Virus (HTLV-I) Circulation in Santiago De Cuba Province (Cuba) Human adult T-cell leukaemia and the HTLV-associated myelopathy/tropical spastic paraparesis constitute the indicative main disease of the HTLV-I virus circulation in endemic areas. The objective of this work was to confirm the existence or not of the HTLVI infection in Santiago de Cuba Province where there have not been reported any HTLV seropositive persons up to the present. We studied 1548 sera samples: 1436 blood donors, 35 transfused patients and 77 persons with clinical symptoms associated to this virus. We used enzyme-linked immunosorbent (EIA) and Western blot assays (DAVIH-BLOT HTLV-I (DAVIH Laboratories, Cuba) to detect and confirm the HTLV-I-specific antibodies.

HTLV-1 bZIP Factor Suppresses Apoptosis by Attenuating the Function of FoxO3a and Altering Its Localization

As the infectious agent causing human adult T-cell leukemia (ATL), the human T-cell leukemia virus type 1 (HTLV-1) virus spreads in vivo primarily by cell-to-cell transmission. However, the factors that determine its transmission efficiency are not fully understood. The viral genome encodes the HTLV-1 bZIP factor (HBZ), which is expressed in all ATL cases and is known to promote T-cell proliferation. In this study, we investigated the hypothesis that HBZ also influences the survival of T cells. Through analyzing the transcriptional profile of HBZ-expressing cells, we learned that HBZ suppressed transcription of the proapoptotic gene Bim (Bcl2l11) and that HBZ-expressing cells were resistant to activation-induced apoptosis. Mechanistic investigations into how HBZ suppresses Bim expression revealed that HBZ perturbs the localization and function of FoxO3a, a critical transcriptional activator of the genes encoding Bim and also Fas ligand (FasL). By interacting with FoxO3a, HBZ not only attenuated DNA binding by FoxO3a but also sequestered the inactive form of FoxO3a in the nucleus. In a similar manner, HBZ also inhibited FasL transcription induced by T-cell activation. Further study of ATL cells identified other Bim perturbations by HBZ, including at the level of epigenetic alteration, histone modification in the promoter region of the Bim gene. Collectively, our results indicated that HBZ impairs transcription of the Bim and FasL genes by disrupting FoxO3a function, broadening understanding of how HBZ acts to promote proliferation of HTLV-1-infected T cells by blocking their apoptosis.

Interferon regulatory factor-4 activates IL-2 and IL-4 promoters in cooperation with c-Rel

Interferon regulatory factor (IRF)-4 is a member of the IRF transcription factor family, whose expression is primarily restricted to lymphoid and myeloid cells. In T-cells, IRF-4 expression is induced by T-cell receptor (TCR) cross-linking or treatment with phorbol-12-myristate-13-acetate (PMA)/Ionomycin, and IRF-4 is thought to be a critical factor for various functions of T-cells. To elucidate the IRF-4 functions in human adult T-cell leukemia virus type 1 (HTLV-1)-infected T-cells, which constitutively express IRF-4, we isolated IRF-4-binding proteins from T-cells, using a tandem affinity purification (TAP)-mass spectrometry strategy. Fourteen proteins were identified in the IRF-4-binding complex, including endogenous IRF-4 and the nuclear factor-kappaB (NF-κB) family member, c-Rel. The specific association of IRF-4 with c-Rel was confirmed by immunoprecipitation experiments, and IRF-4 was shown to enhance the c-Rel-dependent binding and activation of the interleukin-4 (IL-4) promoter region. We also demonstrated that IL-2 production was also enhanced by exogenously-expressed IRF-4 and c-Rel in the presence of P/I, in T-cells, and that the optimal IL-2 and IL-4 productions in vivo was IRF-4-dependent using IRF-4−/− mice. These data provide molecular evidence to support the clinical observation that elevated expression of c-Rel and IRF-4 is associated with the prognosis in adult T-cell leukemia/lymphoma (ATLL) patients, and present possible targets for future gene therapy.

Decreased CXCR3 Expression in CD4+ T Cells Exposed to Asbestos or Derived from Asbestos-Exposed Patients

Asbestos causes malignant tumors such as lung cancer and malignant mesothelioma (MM). To determine whether asbestos exposure causes reduction of antitumor immunity, we established an in vitro T-cell line model of low-dose and continuous exposure to asbestos using an human adult T-cell leukemia virus-1 immortalized human polyclonal T-cell line, MT-2, and revealed that MT-2 cells exposed continuously to asbestos showed resistance to asbestos-induced apoptosis. In addition, the cells presented reduction of surface CXCR3 chemokine receptor expression and IFN-γ production. In this study, to confirm that these findings are suitable for clinical translation, surface CXCR3 and IFN-γ expression were analyzed using freshly isolated human CD4(+) T cells derived from healthy donors and patients with pleural plaque (PP) or MM. The results revealed that CXCR3 and IFN-γ expression in the ex vivo model were reduced in some cases. Additionally, CXCR3 expression in CD4(+) T cells from PPs and MMs was significantly reduced compared with that from healthy donors, and CD4(+) T cells from patients with MMs exhibited a marked reduction in IFN-γ mRNA levels after stimulation in vitro. Moreover, CD4(+)CXCR3(+) T cells in lymphocytes from MMs showed a tendency for an inverse correlation with its ligand CXCL10/IP10 in plasma. These findings show reduction of antitumor immune function in asbestos-exposed patients and indicate that CXCR3, IFN-γ, and CXCL10/IP10 may be candidates to detect and monitor disease status.

Activation of hypoxia-inducible factor 1 in human T-cell leukaemia virus type 1-infected cell lines and primary adult T-cell leukaemia cells

Activation of hypoxia-inducible factor 1 in human T-cell leukaemia virus type 1-infected cell lines and primary adult T-cell leukaemia cells

Inhibition of proliferation by agricultural plant extracts in seven human adult T-cell leukaemia (ATL)-related cell lines

Adult T-cell leukaemia (ATL) is caused by human T-cell leukaemia virus type I (HTLV-I) infection and is resistant to conventional chemotherapy. We evaluated the inhibitory effects of agricultural plants on the proliferation of seven ATL-related human leukaemia cells, using three ATL cell lines (ED, Su9T01 and S1T), two human T-cell lines transformed by HTLV-I infection (HUT-102 and MT-2) and two HTLV-I-negative human T-cell acute lymphoblastic leukaemia cell lines (Jurkat and MOLT-4). A total of 52 samples of 80% ethanol extracts obtained from 30 types of agricultural plants were examined. On the basis of IC(50) values, we selected samples with greater activity than genistein, which was used as a positive control. The highest inhibitory effect was observed with extracts from leaves of Vaccinium virgatum Aiton (blueberry) on four cell lines (ED, Su9T01, HUT-102 and Jurkat); seeds of Momordica charantia L. (bitter gourd) exhibited the second highest activity. The bitter gourd seeds suppressed the proliferation of three cell lines (Su9T01, HUT-102 and Jurkat). The extracts from edible parts of Ipomea batatas LAM. (sweet potato), edible parts of Colocasia esculenta (L.) Schott (taro), skin of taro and seeds of Prunus mume Sieb. et Zucc. (mume) showed markedly greater inhibitory effects on Su9T01 than genistein. These findings suggest that ATL-preventative bioactive compounds may exist in these agricultural plants, which are considered to be functional foods.

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

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

Retraction Note: Inhibition of constitutively active Jak-Stat pathway suppresses cell growth of human T-cell leukemia virus type 1-infected T-cell lines and primary adult T-cell leukemia cells

Retraction Note: Inhibition of constitutively active Jak-Stat pathway suppresses cell growth of human T-cell leukemia virus type 1-infected T-cell lines and primary adult T-cell leukemia cells

Reduction of CXC Chemokine Receptor 3 in anIn VitroModel of Continuous Exposure to Asbestos in a Human T-Cell Line, MT-2

Because patients with silicosis who are chronically exposed to silica particles develop not only pulmonary fibrosis, but also complications involving autoimmune diseases such as rheumatoid arthritis and systemic sclerosis, exposure to asbestos may affect the human immune system. This immunologic effect may impair antitumor immune function because cancer complications such as lung cancer and malignant mesothelioma are found in patients exposed to asbestos. To elucidate the antitumor immune status caused by CD4(+) T cells exposed to asbestos, an in vitro T-cell model of long-term and low-level exposure to chrysotile asbestos was established from a human adult T-cell leukemia virus-1-immortalized human polyclonal T cell line, MT-2, and the resulting six sublines showed resistance to asbestos-induced apoptosis after more than 8 months of continuous exposure. The results of DNA microarray analysis showed that the expression of 139 genes was altered by long-term and low-level exposure to asbestos, and the profile was almost similar among the six sublines when compared with the original MT-2 cells that had never been exposed to asbestos. Pathway and network analysis indicated a down-regulation of IFN-γ signaling and expression of CXC chemokine receptor 3 (CXCR3) in the sublines, whereas ELISA and flow cytometry analysis demonstrated a reduction in Th1-related IFN-γ production and cell-surface CXCR3 expression. These findings suggest that chronic exposure to asbestos may reduce antitumor immune status in CD4(+) T cells, and that an in vitro T-cell model may be useful in identifying molecules related to the impairment of antitumor immune function.

CADM1 Interacts with Tiam1 and Promotes Invasive Phenotype of Human T-cell Leukemia Virus Type I-transformed Cells and Adult T-cell Leukemia Cells

CADM1 encodes a multifunctional immunoglobulin-like cell adhesion molecule whose cytoplasmic domain contains a type II PSD95/Dlg/ZO-1 (PDZ)-binding motif (BM) for associating with other intracellular proteins. Although CADM1 lacks expression in T lymphocytes of healthy individuals, it is overexpressed in adult T-cell leukemia-lymphoma (ATL) cells. It has been suggested that the expression of CADM1 protein promotes infiltration of leukemic cells into various organs and tissues, which is one of the frequent clinical manifestations of ATL. Amino acid sequence alignment revealed that Tiam1 (T-lymphoma invasion and metastasis 1), a Rac-specific guanine nucleotide exchange factor, has a type II PDZ domain similar to those of membrane-associated guanylate kinase homologs (MAGUKs) that are known to bind to the PDZ-BM of CADM1. In this study, we demonstrated that the cytoplasmic domain of CADM1 directly interacted with the PDZ domain of Tiam1 and induced formation of lamellipodia through Rac activation in HTLV-I-transformed cell lines as well as ATL cell lines. Our results indicate that Tiam1 integrates signals from CADM1 to regulate the actin cytoskeleton through Rac activation, which may lead to tissue infiltration of leukemic cells in ATL patients.

9‐Deazaguanine derivatives connected by a linker to difluoromethylene phosphonic acid are slow‐binding picomolar inhibitors of trimeric purine nucleoside phosphorylase

Genetic deficiency of purine nucleoside phosphorylase (PNP; EC 2.4.2.1) activity leads to a severe selective disorder of T-cell function. Therefore, potent inhibitors of mammalian PNP are expected to act as selective immunosuppressive agents against, for example, T-cell cancers and some autoimmune diseases. 9-(5',5'-difluoro-5'-phosphonopentyl)-9-deazaguanine (DFPP-DG) was found to be a slow- and tight-binding inhibitor of mammalian PNP. The inhibition constant at equilibrium (1 mm phosphate concentration) with calf spleen PNP was shown to be = 85 +/- 13 pm (pH 7.0, 25 degrees C), whereas the apparent inhibition constant determined by classical methods was two orders of magnitude higher ( = 4.4 +/- 0.6 nm). The rate constant for formation of the enzyme/inhibitor reversible complex is (8.4 +/- 0.5) x 10(5) m(-1).s(-1), which is a value that is too low to be diffusion-controlled. The picomolar binding of DFPP-DG was confirmed by fluorimetric titration, which led to a dissociation constant of 254 pm (68% confidence interval is 147-389 pm). Stopped-flow experiments, together with the above data, are most consistent with a two-step binding mechanism: E + I <--> (EI) <--> (EI)*. The rate constants for reversible enzyme/inhibitor complex formation (EI), and for the conformational change (EI) <--> (EI)*, are k(on1) = (17.46 +/- 0.05) x 10(5) m(-1).s(-1), k(off1) = (0.021 +/- 0.003) s(-1), k(on2) = (1.22 +/- 0.08) s(-1) and k(off2) = (0.024 +/- 0.005) s(-1), respectively. This leads to inhibition constants for the first (EI) and second (EI)* complexes of K(i) = 12.1 nM (68% confidence interval is 8.7-15.5 nm) and = 237 pm (68% confidence interval is 123-401 pm), respectively. At a concentration of 10(-4) m, DFPP-DG exhibits weak, but statistically significant, inhibition of the growth of cell lines sensible to inhibition of PNP activity, such as human adult T-cell leukaemia and lymphoma (Jurkat, HuT78 and CCRF-CEM). Similar inhibitory activities of the tested compound were noted on the growth of lymphocytes collected from patients with Hashimoto's thyroiditis and Graves' disease. The observed weak cytotoxicity may be a result of poor membrane permeability.

Antiproliferative Activity of Purine Nucleoside Phosphorylase Multisubstrate Analogue Inhibitors Containing Difluoromethylene Phosphonic Acid against Leukaemia and Lymphoma Cells

Potent inhibitors of purine nucleoside phosphorylase (PNP) are expected to act as selective agents against T-cell tumours. Five compounds with guanine, three with hypoxanthine, and five with 9-deazaguanine, all connected by a linker with difluoromethylene phosphonic acid, were studied on their inhibitory potential against human and calf PNPs. Antiproliferative activity of these analogues against lymphocytes as well as lymphoma and leukaemia cells has been also investigated. All tested compounds act as multisubstrate analogue inhibitors of PNP with the apparent inhibition constants in the range 5-100 nm, and also show a slight antiproliferative activity. Analogues with 9-deazaguanine aglycone have better anti-leukaemic and anti-lymphoma activities compared to the guanine and hypoxanthine analogues, and applied in the concentration of 100 mum, caused a statistically significant decrease in the cell viability in all human leukaemia and lymphoma cells used. Despite the high PNP inhibitory potential of tested analogues, no differences were observed between the effects on the growth of tumour cells sensible to the inhibition of PNP, such as human adult T-cell leukaemia and lymphoma cells, and other investigated cells. Obtained poor effects on cell proliferation could be explained probably by a poor ability of tested compounds to penetrate cell membranes.

Inhibition of the SDF-1α–CXCR4 axis by the CXCR4 antagonist AMD3100 suppresses the migration of cultured cells from ATL patients and murine lymphoblastoid cells from HTLV-I Tax transgenic mice

Adult T-cell leukemia (ATL) is a T-cell malignancy caused by human T lymphotropic virus type I, and presents as an aggressive leukemia with characteristic widespread leukemic cell infiltration into visceral organs and skin. The molecular mechanisms associated with leukemic cell infiltration are poorly understood. We have used mouse models of ATL to investigate the role of chemokines in this process. Transfer of splenic lymphomatous cells from transgenic to SCID mice reproduces a leukemia and lymphoma that is histologically identical to human disease. It could be shown that lymphomatous cells exhibit specific chemotactic activity in response to stromal cell-derived factor-1alpha (SDF-1alpha). Lymphomatous cells exhibited surface expression of CXCR4, the specific receptor of SDF-1alpha. AMD3100, a CXCR4 antagonist, was found to inhibit both SDF-1alpha-induced migration and phosphorylation of extracellular signal-related kinase 1/2. Investigation of cultured cells from human ATL patients revealed identical findings. Using the SCID mouse model, it could be demonstrated that AMD3100 inhibited infiltration of lymphomatous cells into liver and lung tissues in vivo. These results demonstrate the involvement of the SDF-1alpha/CXCR4 interaction as one mechanism of leukemic cell migration and this may provide a novel target as part of combination therapy for ATL.

Adult T-cell leukemia-like disease in monkey naturally infected with simian retrovirus related to human T-cell leukemia virus type I.

Spontaneous T-cell leukemia similar to human adult T-cell leukemia (ATL) was found in an African green monkey naturally infected with simian retrovirus closely related to human T-cell leukemia virus type I (HTLV-I). Monoclonal integration of the simian retrovirus was detected in the primary leukemic cells, suggesting an association of the retrovirus with ATL-like leukemia in the monkey.

Highly Enhanced Expression of CD70 on Human T-Lymphotropic Virus Type 1-Carrying T-Cell Lines and Adult T-Cell Leukemia Cells

Human T-lymphotropic virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia (ATL). In Japan, the number of HTLV-1 carriers is estimated to be 1.2 million and more than 700 cases of ATL have been diagnosed every year. Considering the poor prognosis and lack of curative therapy of ATL, it seems mandatory to establish an effective strategy for the treatment of ATL. In this study, we attempted to identify the cell surface molecules that will become suitable targets of antibodies for anti-ATL therapy. The expression levels of approximately 40,000 host genes of three human T-cell lines carrying HTLV-1 genomes were analyzed by oligonucleotide microarray and compared with the expression levels of the genes in an HTLV-1-negative T-cell line. The HTLV-1-carrying T-cell lines used for experiments had totally different expression patterns of viral genome. Among the genes evaluated, the expression levels of 108 genes were found to be enhanced more than 10-fold in all of the T-cell lines examined and 11 of the 108 genes were considered to generate the proteins expressed on the cell surface. In particular, the CD70 gene was upregulated more than 1,000-fold and the enhanced expression of the CD70 molecule was confirmed by laser flow cytometry for various HTLV-1-carrying T-cell lines and primary CD4(+) T cells isolated from acute-type ATL patients. Such expression was not observed for primary CD4(+) T cells isolated from healthy donors. Since CD70 expression is strictly restricted in normal tissues, such as highly activated T and B cells, CD70 appears to be a potential target for effective antibody therapy against ATL.