Gamma-secretase inhibitor does not induce cytotoxicity in adult T-cell leukemia cell lines despite NOTCH1 expression.

BACKGROUND: Activated mutations in NOTCH1 are drivers of T-cell type acute lymphoblastic leukemia/lymphoma. The γ-secretase inhibitor (GSI), which suppresses the function of NOTCH1, is expected to be a molecular-targeted agent. NOTCH1 is also expressed in other malignant neoplasms. We aimed to determine the function of NOTCH1 expression and the effects of GSI on adult T-cell leukemia/lymphoma (ATL) caused by long-term human T-cell leukemia virus type I (HTLV-1) infection. METHODS: We analyzed the expression of NOTCH1 in six ATL- and HTLV-1-infected cell lines and investigated the influence of activated NOTCH1 (i.e., the cleaved form of NOTCH1) together with GSI on cell proliferation. RESULTS: Activated NOTCH1 found in ATL- and HTLV-1-infected cell lines was undetectable after incubation with GSI, regardless of Tax expression (HTLV-1-coded protein). Whole-exome sequencing revealed that activated NOTCH1 mutations were undetectable in six ATL- and HTLV-1-infected cell lines, regardless of abundant NOTCH1 expression. Moreover, GSI did not suppress the growth of ATL cell lines. CONCLUSIONS: These findings suggested that NOTCH1 protein is constitutively activated but is likely a passenger during NOTCH1-mutation-negative ATL cell proliferation.

A survivin-responsive, conditionally replicating adenovirus induces potent cytocidal effects in adult T-cell leukemia/lymphoma.

BACKGROUND: Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell malignancy caused by long-term human T-cell leukemia virus type I (HTLV-1) infection. Survivin-responsive, conditionally replicating adenoviruses regulated by multiple tumor-specific factors (Surv.m-CRAs), in which the expression of the adenoviral early region 1A gene is regulated by the survivin (BIRC5) promoter, can be used to treat several cancers. As survivin is overexpressed in ATL, we examined the effects of Surv.m-CRAs on ATL-selective replication and survival. METHODS: We tested two ATL cell lines and four HTLV-1-infected T-cell lines. The cells were subjected to infection with either E1-deleted, replication-defective adenoviruses or Surv.m-CRAs at various multiplicities of infection. RESULTS: Strong activation of survivin promoter was observed in all six cell lines. Moreover, the expression of the coxsackie and adenovirus receptor (CAR), which is important for adenoviral infection, was high in the cell lines. In contrast, we observed the absence of survivin promoter activity and a low expression of CAR in activated peripheral blood lymphocytes (PBLs) from healthy subjects. Surv.m-CRAs actively replicated and induced cytocidal effects in five out of six cell lines; conversely, we observed minimal viral replication and no marked cytotoxicity in normal activated PBLs. CONCLUSIONS: This is the first report demonstrating that Surv.m-CRAs constitute attractive potential anti-ATL agents.

A retrospective analysis of treatment outcomes in adult T cell leukemia/lymphoma patients with aggressive disease treated with or without allogeneic stem cell transplantation: A single-center experience.

Adult T cell leukemia/lymphoma (ATL) is an aggressive peripheral T cell neoplasm with very poor prognosis. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been reported as a curative treatment modality for ATL. However, there are no reports comparing chemotherapy alone with allo-HSCT in ATL. In this report, we retrospectively analyzed data for patients treated with (n = 29, median age 55 years) or without allo-HSCT (n = 37, median age 58 years) for ATL in Kagoshima University Hospital, located in one of the most endemic areas of human T cell lymphotropic leukemia virus type 1 infection. Forty patients (61%) started coordination for allo-HSCT. Ten patients (34.4%) received allo-HSCT while in complete remission (CR), whereas the others were not in CR. Twenty-five patients (86.2%) received reduced-intensity conditioning, and the others received myeloablative conditioning. With a median follow-up period for survivors of 41 months (range, 5 to 125 months), the 3-year overall survival (OS) rate from first chemotherapy for all patients (with or without allo-HSCT) was 35.2%. The 3-year OS from first chemotherapy for patients who received allo-HSCT or only chemotherapy was 44.9% and 27.7%, respectively. Univariate analyses revealed that high serum soluble IL-2 receptor (sIL-2R) levels (≥ 2000 U/mL) just before the conditioning regimen and progressive disease (PD) status at HSCT (according to Japan Clinical Oncology Group Study 0907 criteria) were significant risk factors for OS in the allo-HSCT group. Multivariate analyses revealed that PD status was a significant risk factor for OS in the allo-HSCT group. In the chemotherapy-only group, the 3-year OS rate was 61.5% (95% CI, 30.8% to 81.8%) in patients with serum sIL-2R levels < 2000 U/mL for > 3 months. In contrast, the 3-year OS rate was 5.7% (95% CI, .4% to 22.4%) in patients who did not achieve serum sIL-2R levels < 2000 U/mL for >3 months. Our single-center cohort experience indicates that chemosensitivity is the most important prognostic factor for OS in ATL patients and the use of allo-HSCT is limited in chemorefractory patients with aggressive ATL disease. In the chemosensitive patients, allo-HSCT demonstrated a tendency toward better OS. Further clinical studies are warranted to determine optimal treatments for patients who are less sensitive to conventional chemotherapy.

CD160 expression defines a uniquely exhausted subset of T lymphocytes in HTLV-1 infection.

HTLV-1 infection is a life-long retroviral infection. Chronic viral antigenic stimulation induces persistent infection which results in a clinically asymptomatic carrier state. Only a minor proportion of infected individuals develop adult T cell leukemia/lymphoma (ATLL) or HTLV-1-associated myelopathy/tropical spastic myelopathy (HAM/TSP). This is dependent on a balance of host and genetic factors. CD8+ cytotoxic T lymphocyte function is important in the immune response against viral infection; however, the contribution of CD160 receptor associated with CD8+ T lymphocytes is unclear. Thus, we sought to decipher its role on CTL function in HTLV-1 infection. Here, we report high frequencies of CD160 on CD8+ T cells, with significantly higher levels on HTLV-1 specific CD8+ T cells. Intercepting the CD160 pathway via blockade of the receptor or its ligand, herpes virus entry mediator (HVEM) resulted in improved perforin production and CD107a degranulation of HTLV-1 specific CD8+ T cells. Analysis of the CD160-expressing CD8+ cells demonstrated a unique subset associated with a highly differentiated effector memory based on CD45RA and CCR7 co-expression, increased expression of inhibitory molecules, 2B4 and PD1. Altogether, these results suggest a role for CD160/HVEM pathway in regulating immune response against HTLV-1 infection which may prove promising in the development of immune therapies for the treatment of HTLV-1 infection and other associated disorders.

Prevention of human T-cell lymphotropic virus type 1 infection and adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is a highly aggressive peripheral T-cell malignancy that develops after long-term chronic infection with human T-cell lymphotropic virus type-1 (HTLV-1). Despite the recent advances in chemotherapy, allogeneic hematopoietic stem cell transplantation (alloHSCT), and supportive care, the prognosis for patients with ATL is one of the poorest among hematological malignancies; overall survival (OS) at 3 years is only 24 % in the more aggressive subtypes of ATLL. HTLV-1 is a human retrovirus infecting approximately 10-20 million people worldwide, particularly in southern and southeastern Japan, the Caribbean, highlands of South America, Melanesia, and Equatorial Africa. Despite this high frequency of human infection, only 2-5 % of HTLV-1-infected individuals develop ATLL. Three major routes of viral transmission have been established: (1) mother-to-child transmission through breast-feeding; (2) sexual transmission, predominantly from men to women; and (3) cellular blood components. Multiple factors (e.g., virus, host cell, and immune factors) have been implicated in the development of ATLL, although the underlying mechanisms of leukemogenesis have not been fully elucidated. No preventive vaccine against HTLV-1 is currently available, and interrupting the well-recognized primary modes of HTLV-1 transmission is the mainstay of ATLL prevention. Prevention of mother-to-child transmission through the replacement of breast-feeding has been shown to have the most significant impact on the incidence of HTLV-1 infection, and public health policies should consider the risk of malnutrition, especially in developing countries where malnutrition is the significant cause of infant mortality.

Two autopsy cases of severe fever with thrombocytopenia syndrome (SFTS) in Japan: a pathognomonic histological feature and unique complication of SFTS.

We report two autopsy cases of severe fever with thrombocytopenia syndrome (SFTS) with a high fatality rate in aged Japanese patients. Both cases were caused by a tick-bite. The pathognomonic histological feature was necrotizing lymphadenitis of systemic lymphoid tissue with SFTS viruses and SFTSV-RNA copies. Marked fungal infections were also observed in the lungs of both patients. Since cellular immune function may be suppressed in SFTS patients, physicians should be aware of possible fungal infections.

Anticancer agents targeted to sirtuins.

Sirtuins are nicotinamide adenine dinucleotide+-dependent deacetylases of which there are seven isoforms (SIRT1-7). Sirtuin activity is linked to gene expression, lifespan extension, neurodegeneration, and age-related disorders. Numerous studies have suggested that sirtuins could be of great significance with regard to both antiaging and tumorigenesis, depending on its targets in specific signaling pathways or in specific cancers. Recent studies have identified small chemical compounds that modulate sirtuins, and these modulators have enabled a greater understanding of the biological function and molecular mechanisms of sirtuins. This review highlights the possibility of sirtuins, especially SIRT1 and SIRT2, for cancer therapy targets, and focuses on the therapeutic potential of sirtuin modulators both in cancer prevention and treatment.

Assessment of peripheral blood CD4+ adenosine triphosphate activity in patients with rheumatoid arthritis.

OBJECTIVE: The ability of the ImmuKnow (Cylex) assay to predict the risk of infection in rheumatoid arthritis (RA) patients receiving synthetic or biological disease-modifying antirheumatic drugs (DMARDs) was examined. METHODS: The amount of adenosine triphosphate (ATP) produced by CD4+ cells in response to phytohemagglutinin was measured in whole blood from 117 RA patients without infection versus 17 RA patients with infection, and compared with results in 75 healthy controls. RESULTS: The mean ATP level was significantly lower in patients with infection compared to both healthy controls (P < 0.0005) and patients without infection (P = 0.040). Also, the mean ATP level in patients without infection was significantly lower than that in healthy controls (P = 0.012). There was no correlation between the ATP level and the Disease Activity Score in 28 joints. CONCLUSION: ImmuKnow assay results may be effective in identifying RA patients at increased risk of infection, but the results showed no correlation with RA activity. Larger studies are required to establish the clinical advantages of this assay in RA treatment.

High expression of the longevity gene product SIRT1 and apoptosis induction by sirtinol in adult T-cell leukemia cells.

Adult T-cell leukemia-lymphoma (ATL) is an aggressive peripheral T-cell neoplasm that develops after long-term infection with human T-cell leukemia virus (HTLV-1). SIRT1, a nicotinamide adenine dinucleotide(+)-dependent histone/protein deacetylase, plays a crucial role in various physiological processes, such as aging, metabolism, neurogenesis and apoptosis, owing to its ability to deacetylate numerous substrates, such as histone and NF-κB, which is implicated as an exacerbation factor in ATL. Here, we assessed how SIRT1 is regulated in primary ATL cells and leukemic cell lines. SIRT1 expression in ATL patients was significantly higher than that in healthy controls, especially in the acute type. Sirtinol, a SIRT1 inhibitor, induced significant growth inhibition or apoptosis in cells from ATL patients and leukemic cell lines, especially HTLV-1-related cell lines. Sirtinol-induced apoptosis was mediated by activation of the caspase family and degradation of SIRT1 in the nucleus. Furthermore, SIRT1 knockdown by SIRT1-specific small interfering RNA caused apoptosis via activation of caspase-3 and PARP in MT-2 cells, HTLV-1-related cell line. These results suggest that SIRT1 is a crucial antiapoptotic molecule in ATL cells and that SIRT1 inhibitors may be useful therapeutic agents for leukemia, especially in patients with ATL.

The bioassay-guided isolation of growth inhibitors of adult T-cell leukemia (ATL), from the Jamaican plant Hyptis verticillata, and NMR characterization of hyptoside.

Through bioassay-guided isolation, five compounds with growth inhibitory activity on S1T, an adult T-cell leukemia (ATL) cell line, were isolated from the crude methanol extract of the aerial parts of Hyptis verticillata.

Target epitopes of HTLV-1 recognized by class I MHC-restricted cytotoxic T lymphocytes in patients with myelopathy and spastic paraparesis and infected patients with autoimmune disorders.

Human T-cell lymphotropic virus type I (HTLV-1) causes adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The different patterns of clinical diseases are thought to be linked to immunogenetic host factors. A variety of autoimmune diseases, such as Sjögren's syndrome, have been reported in persons infected with HTLV-1, although the precise relationship between these disorders and HTLV-1 infection remains unknown. There is no report on the repertoire of HTLV-1-specific CD8+ T-cells in HAM/TSP patients or carriers with autoimmune diseases, both characterized by an abnormal immune state. In this study, to characterize HTLV-1-specific CD8+ T-cells in asymptomatic HTLV-1 carriers, HAM/TSP patients and carriers with autoimmune diseases, we examined the frequency and diversity of HTLV-1-specific CD8+ T-cells using HTLV-1 tetramers. HTLV-1 Env-specific CD8+ T-cells were significantly more frequent in HAM/TSP and carriers with autoimmune diseases compared with asymptomatic HTLV-1 carriers, while the frequency of HTLV-1 Tax-specific CD8+ T-cells was not significantly different among them. CD8+ cells binding to HTLV-1 Tax tetramers in carriers with autoimmune diseases were significantly reduced compared with HAM/TSP patients. This study demonstrates the importance of CD8+ T-cells recognizing HTLV-1 Env-tetramers in HAM/TSP patients and carriers with autoimmune diseases, thereby suggesting that the diversity, frequency and repertoire of HTLV-1 Env-specific CD8+ T-cell clones may be related to the hyperimmune response in HAM/TSP and carriers with autoimmune diseases, although different immunological mechanisms may mediate the hyperimmunity in these conditions.

Two cytotoxic squalene-derived polyethers from the Japanese red alga Chondria armata.

The red alga Chondria armata is known to produce and contain a rich diversity of secondary metabolites, such as domoic acid-related alkaloids and triterpene polyethers. Our investigation on red alga C. armata from Kagoshima coast, Japan, resulted in the isolation of two new triterpene polyethers, bandokorols A (1) and B (2). The structures of these compounds were determined based on spectroscopic data such as infrared (FTIR), 1H-NMR, APT, 1H-1H-COSY, HSQC, HMBC, NOESY and FAB mass spectrometry (HRFABMS). The anticancer potentials of these compounds were tested against adult T-cell leukaemia (ATL), S1T cells and their IC50 values are reported here.

Correction to: Treatment of aggressive adult T-cell leukemia/lymphoma: a retrospective study in a hospital located in HTLV-1 highly endemic area.

In the original publication of the article, Table 5 was published with incorrect contents. The correct Table 5 is given in this correction.

Treatment of aggressive adult T-cell leukemia/lymphoma: a retrospective study in a hospital located in HTLV-1 highly endemic area.

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell neoplasm associated with the human T-cell leukemia virus type-I (HTLV-1); prognosis still remains very poor. We retrospectively reviewed the treatment of 198 patients with acute-, lymphoma- and unfavorable chronic-type ATL (aggressive ATL) diagnosed from 2005 to 2014 in a hospital located in an area of Japan in which HTLV-1 is highly endemic. One-hundred forty-three, and 35 patients were treated using OPEC/MPEC and VCAP-AMP-VECP, respectively. OPEC/MPEC was mainly used until around 2010, and gradually switched to VCAP-AMP-VECP, especially for younger patients. The 2-year overall survival for patients treated by VCAP-AMP-VECP was significantly higher than that using OPEC/MPEC for patients < 70 years old (y.o.), but not for patients ≥ 70 y.o. A less intensive chemotherapy OPEC/MPEC could be performed without reducing dose intensity, even in elderly patients, and its therapeutic outcome is not inferior to that of VCAP-AMP-VECP. It is difficult to draw definite conclusion from this small retrospective study; however, OPEC/MPEC may represent an alternative option for elderly patients with aggressive ATL.

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.

Aggressive NK cell leukaemia after splenectomy: association with CD95-resistant memory T-cell proliferation and recalcitrant clinical course of haemophagocytic syndrome.

We describe a 44-yr-old Japanese woman with persistent polyclonal T-cell proliferation and recalcitrant clinical course of haemophagocytic syndrome (HPS). T cells bearing alphabeta T-cell receptors (TCR) expressed increased amounts of CD95 and of CD45RO, which are phenotypically memory T cells. The TCR repertoire was broad and diverse. Regardless of CD95 expression, these cells were resistant to CD95-mediated apoptosis. Aggressive natural killer cell leukaemia (ANKL) without an association with Epstein-Barr virus was detected 1 month after therapeutic splenectomy that followed 3 yr of immunosuppressive therapy against HPS. The immunophenotype of these leukaemia cells was CD56, CD16(dim), CD7, CD45RA and they expressed some CD2, CD8 and HLA-DR. Moreover, hyperdiploid clones with complex chromosomal abnormalities were also detected. Latent NK-cell malignancy seemed to cause the CD95-resistant memory T-cell proliferation and splenectomy resulted in overt ANKL progression. There should be careful consideration of the risks versus benefits of splenectomy in HPS, in light of the possibility of fatal leukaemia/lymphoma progression.

In vitro effects of arsenic trioxide, interferon α and zidovudine in adult T cell leukemia/lymphoma cells.

Despite the efficacy of combination chemotherapy with arsenic trioxide (ATO), interferon α (IFN) and zidovudine (AZT) for adult T cell leukemia/lymphoma (ATL), the precise mechanism underlying this combination treatment effect is unknown. In the present study, ATO/IFN/AZT was examined in an ATL leukemic cell line (S1T, non-Tax expressing), a human T-lymphotropic virus 1 (HTLV-1)-infected cell line (MT2, Tax-expressing) and primary ATL cells from patients with acute and chronic ATL. IFN/AZT marginally inhibited MT2 cell proliferation, but substantially inhibited S1T cell proliferation. IFN/AZT increased the cleavage of numerous caspases and PARP in S1T cells, and regulated the signal transducer and activator of transcription 1 and nuclear factor-κB signaling pathway. These effects represent the potential anti-ATL mechanisms of INF/AZT in vitro. In addition, the combination of ATO and IFN/AZT demonstrated synergistic effects on S1T cells. Therefore, the Tax-independent mechanism underlying the anti-ATL effect of ATO must be further elucidated.

Development of sugar chain-binding single-chain variable fragment antibody to adult T-cell leukemia cells using glyco-nanotechnology and phage display method.

Adult T-cell leukemia (ATL) is an intractable blood cancer caused by the infection of human T-cell leukemia virus type-1, and effective medical treatment is required. It is known that the structure and expression levels of cell surface sugar chains vary depending on cell states such as inflammation and cancer. Thus, it is expected that the antibody specific for ATL cell surface sugar chain would be an effective diagnostic tool and a strong candidate for the development of an anti-ATL drug. Here, we developed a stable sugar chain-binding single-chain variable fragment antibody (scFv) that can bind to ATL cells using a fibre-type Sugar Chip and phage display method. The fiber-type Sugar Chips were prepared using O-glycans released from ATL cell lines. The scFv-displaying phages derived from human B cells (diversity: 1.04 × 108) were then screened using the fiber-type Sugar Chips, and an O-glycan-binding scFv was obtained. The flow cytometry analysis revealed that the scFv predominantly bound to ATL cell lines. The sugar chain-binding properties of the scFv was evaluated by array-type Sugar Chip immobilized with a library of synthetic glycosaminoglycan disaccharide structures. Highly sulphated disaccharide structures were found to have high affinity to scFv.

A new cytogenetic abnormality, t(2;7)(q33;q36), in acute promyelocytic leukemia.

We report the case of a patient with acute promyelocytic leukemia (APL) carrying a novel chromosomal abnormality, t(2;7)(q33;q36). The 54-year-old woman was morphologically diagnosed with APL through bone marrow aspiration. The proportion of blast cells in bone marrow was 78%, including cells displaying Auer rods and faggot cells. Chromosomal analysis revealed the karyotype 46,XX,t(2;7)(q33;q36)[17]/46,XX[3]. The t(15;17) was not detected with conventional cytogenetic analysis. However, reverse transcriptase-polymerase chain reaction revealed the presence of a PML/RARA fusion gene. Cells displaying t(2;7)(q33;q36) disappeared after complete remission was achieved, using induction chemotherapy. Although several additional chromosomal abnormalities have been reported, this t(2;7)(q33;q36) without the classic t(15;17) represents a novel chromosomal abnormality associated with APL.