AbstractAdult T-cell Leukemia/lymphoma Research Articles

Dual targeting of aberrant DNA and histone methylation synergistically suppresses tumor cell growth in ATL.

Adult T-cell leukemia/lymphoma (ATL) is a malignancy of mature CD4+ T cells caused by human T-cell lymphotropic virus type 1 (HTLV-1)-induced T-cell transformation. After infection with HTLV-1, it takes several decades for HTLV-1 carriers to develop ATL. The prognosis of ATL remains poor despite several new agents being approved in the last few years. Recently, it has been noted that epigenetic abnormalities, both DNA methylation and trimethylation at histone H3Lys27 (H3K27me3), contribute to ATL leukemogenesis. Here, we investigated the effect of combination treatment with DNA demethylating agents (azacitidine [AZA], decitabine (DAC), and OR-2100 (OR21), which is a silylated derivative of DAC) and inhibitors of enhancer of zeste homolog 2 (EZH2) (EPZ-6438 and DS-3201b), which catalyze trimethylation of H3K27, in ATL. The combination of DAC and OR21 but not AZA with EZH inhibitors exhibited synergistic anti-ATL effects invitro and invivo, concomitant with DNA demethylation and reduction of H3K27me3. The combination induced gene expression reprogramming. Dual-specificity phosphatase 5 (DUSP5), an extracellular signal-regulated kinase (ERK)-specific phosphatase, was identified as a key molecule that mediated the inhibitory effect of combination treatment by inactivating the ERK signaling pathway. DUSP5 was downregulated by DNA methylation and H3K27me3 accumulation in the promoter region in HTLV-1-infected cells from patients with ATL during ATL leukemogenesis. The present results demonstrate that dual targeting of aberrant DNA and histone methylation synergistically suppresses tumor cell growth by restoring DUSP5, and that dual targeting of aberrant DNA and histone methylation is a feasible therapeutic approach for ATL.

Cutaneous Manifestations and Treatment Advances of Adult T-Cell Leukemia/Lymphoma

Abstract Adult T-cell leukemia/lymphoma (ATLL) is an aggressive peripheral T-cell lymphoma caused by the human T lymphotropic virus type-1. The skin is affected in approximately half of ATLL patients, and skin lesions may be the first manifestation of the disease. The skin lesions of ATLL are polymorphous, and depend on the type of skin eruption, which makes it possible for doctors to predict the prognosis of the disease based on the characteristics of skin lesions. In this review article, we describe the clinical manifestations and histopathological patterns of skin lesions in ATLL, focus on its diagnostic and prognostic significance, and also summarize the advances in the treatment of ATLL.

Development of a novel Indium-111 radiolabeled mogamulizumab targeting CCR4 for imaging adult T-cell leukemia/lymphoma in vivo.

Adult T-cell leukemia/lymphoma (ATL), caused by human T-cell lymphotropic virus type I (HTLV-1) infection, is among the most aggressive categories and has the worst prognosis among T-cell lymphomas. Mogamulizumab, an anti-CC chemokine receptor 4 (CCR 4), has been shown to be effective in the treatment of ATL; however, some ATL cases are often resistant, particularly the lymphoma-type ATL. To evaluate drug delivery in vivo and identify the distribution of CCR4-positive cells in the body, we developed a novel mogamulizumab tracer labeled with Indium-111(111In) via diethylenetriaminepentaacetic acid (DTPA) for single-photon emission computerized tomography (SPECT), named [111In]In-DTPA-mogamulizumab, and evaluated its potential for visualizing CCR4 expression in vivo. [111In]In-DTPA-mogamulizumab was added to HCT116/CCR4 or HCT116/empty vector (EV) cells, and their radioactivity was measured 1h after administration. A blocking study was additionally performed by treating HCT116/CCR4 cells with excess mogamulizumab in addition to [111In]In-DTPA-mogamulizumab. The biodistribution and SPECT imaging of [111In]In-DTPA-mogamulizumab in HCT116/CCR4 and HCT116/EV dual-xenografted BALB/c-nu mice were evaluated for 72h after intravenous injection. [111In]In-DTPA-mogamulizumab was acquired with a radiochemical purity > 95%. The cellular uptake level of [111In]In-DTPA-mogamulizumab by HCT116/CCR4 cells was significantly higher than that by HCT116/EV cells (HCT116/CCR4: 0.951 ± 0.069, HCT116/EV: 0.006 ± 0.001%dose/mg protein, p < 0.01), and the uptake was significantly suppressed by co-incubation with excess mogamulizumab (0.013 ± 0.003%dose/mg protein, p < 0.01). In the in vivo study, the radioactivity of the HCT116/CCR4 tumor tissue was significantly higher than that of the HCT116/EV tumor tissue at 72h after the administration of [111In]In-DTPA-mogamulizumab (HCT116/CCR4: 20.5 ± 5.4, HCT116/EV: 5.7 ± 1.0%ID/g), and HCT116/CCR4 tumors were clearly and specifically visualized on SPECT imaging. We have successfully developed a novel SPECT imaging tracer targeting CCR4, [111In]In-DTPA-mogamulizumab, which showed good specificity and pharmacokinetics, indicating potential in visualizing CCR4 expression in vivo.

SAT-LB309 Amphotericin B Induced Hypocalcemia in a Patient With Severe Hypercalcemia Due to Acute T-Cell Leukemia/Lymphoma

SAT-LB309 Amphotericin B Induced Hypocalcemia in a Patient With Severe Hypercalcemia Due to Acute T-Cell Leukemia/Lymphoma

Inhibition of I\u03baB\u03b1 phosphorylation potentiates regulated cell death induced by azidothymidine in HTLV-1 infected cells

Adult T cell leukemia/lymphoma (ATL) can be susceptible, at least transiently, to treatments with azidothymidine (AZT) plus IFNα and/or arsenic trioxide. However, the real role of AZT in this effect is still unclear. In fact, while reverse transcriptase (RT) inhibition could explain reduction of clonal expansion and of renewal of HTLV-1 infected cells during ATL progression, this effect alone seems insufficient to justify the evident and prompt decrease of the pro-viral load in treated patients. We have previously demonstrated that AZT is endowed with an intrinsic pro-apoptotic potential towards both peripheral blood mononuclear cells from healthy donors or some tumor cell lines, but this cytotoxic potential cannot be fully achieved unless IκBα phosphorylation is inhibited. Since the constitutive activation of NF-kappa B (NF-κB) appears a common biological basis of HTLV-1-infected cells, a pharmacological inhibition of IκBα phosphorylation seems a potential strategy for treating and preventing HTLV-1 related pathologies. In this study, we have demonstrated that a combination treatment with the IκBα phosphorylation inhibitor Bay 11-7085 and AZT induced increased levels of regulated cell death (RCD) by apoptosis compared to the single treatments in HTLV-1 infected cells of different origin. Importantly, levels of RCD were considerably higher in infected cells in comparison with the uninfected ones. Inhibition of NF-κB activation following the combined treatment was confirmed by analysis of both gel-shift and functional activity of the NF-κB complex proteins, p65/p52. Moreover, a transcriptional analysis revealed that the addition of Bay 11-7085 to AZT treatment in HTLV-1-infected cells modified their transcriptional profile, by inducing the upregulation of some pro-apoptotic genes together with the downregulation of some anti-apoptotic genes. Our data suggest that addition of adequate concentrations of IκBα phosphorylation inhibitor to therapeutic regimens including AZT could be a promising strategy in ATL.

Genome-Wide CRISPR Library Screening Identifies CDK6 As Genetic Vulnerability in Adult T-Cell Leukemia/Lymphoma

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive hematological malignancy associated with the retrovirus human T-cell lymphotropic virus type I. Clinical outcomes of currently available chemotherapies are generally inferior with extremely poor prognosis. Previous studies have recently utilized next generation sequencing technology for the identification of mutated genes that may be pivotal in the pathogenesis of ATLL. However, the identification of indispensable genes for the proliferation and/or survival of ATLL cells remains a formidable challenge due to the complexity of genomic/epigenetic alterations in the ATLL genome. To investigate previously undescribed therapeutic targets in ATLL, we performed a genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screening to identify genetic vulnerabilities in ATLL cells. Three ATLL cell lines were transduced with lentiviral construct for Cas9 nuclease, followed by lentiviral delivery of the human CRISPR Brunello pooled library (Addgene 73178) of 76,456 single-guide RNAs targeting 19,144 protein-coding genes to cause DNA double-stranded cleavage by the Cas9 nuclease and loss-of-function of the respective genes. Compared with the control cell lines, 23 essential genes, including BATF3 (which we previously discovered by shRNA library screening; Nakagawa et al., Cancer Cell. 34:286-297. 2018) and novel genes (CDK6, JUNB, STAT3, and CCND2) were identified to be involved in ATLL cell proliferation and/or survival. Among these, CDK6 (cyclin-dependent kinase 6), a critical regulatory serine/threonine kinase that forms heterodimers with D-type cyclins, had the best score. The CDK6/D-type cyclin complex regulates E2F transcription factors through the phosphorylation of Rb (retinoblastoma protein), resulting in G1-S transition of the cell cycle. Utilizing publicly available microarray data from peripheral T-cell lymphoma patients, we demonstrated the higher expression of CDK6 in ATLL than that of the other subtypes of T-cell lymphomas, which prompted us to focus on CDK6 as a therapeutic molecular target in ATLL. In confirmatory experiments, two sgRNAs targeting the coding sequences of CDK6 exhibited strong toxicity in five ATLL cell lines in a temporal fashion, which was mediated by G1 cell arrest and partially through apoptosis. We confirmed on-target effect of the sgCDK6 by successfully rescuing cells from toxicity using retroviruses expressing sgRNA-resistant CDK6 cDNA in two ATLL cell lines. The knockout of CDK6 and decrease in the level of phosphorylated Rb were confirmed by immunoblot of sgCDK6-transduced ATLL cell lines. Collectively, the data showed an essential role for CDK6 in cellular proliferation and survival in ATLL. Of the 19,144 genes examined, CDK6 was considered the best vulnerable target for ATLL; therefore, we extended our analysis to evaluate the pharmacological inhibition of CDK6 in ATLL cells. Palbociclib, FDA-approved CDK4/6 inhibitor for breast cancer, was toxic in 11 ATLL cell lines and in four primary ATLL cells but the range of IC50 values were relatively broad (9-6500 nM) among ATLL lines. Because aproximately 20% of ATLL patients carry genetic alteration in a cell cycle/apoptosis regulator TP53 gene, we hypothesized that TP53 alteration may affect the sensitivity of ATLL cells to palbociclib. First, we assessed TP53 status of ATLL cell lines by Sanger sequencing and immunoblotting and showed that six TP53-altered ATLL cell lines exhibited significantly higher IC50 for palbociclib compared with five TP53-intact ATLL cell lines (p&lt;0.05). Notably, CRISPR-mediated TP53 knockout in a TP53-intact ATLL cell line, which exhibited increased resistance to palbociclib, supported the notion that TP53 is a potential molecular biomarker for palbociclib in ATLL. As a further confirmation of our in vitro findings, treatment of a TP53-intact ATLL cell line-xenograft mouse model with palbociclib showed significant inhibition of tumor growth without systemic toxicity. Through the findings of this study, we have provided evidence that CDK6 can serve as a novel therapeutic target for ATLL. We proposes that CDK6 inhibition with CDK4/6 inhibitor palbociclib, together with the biomarker anaylsis including TP53 status, is worth to be evaluated as a therapeutic strategy for ATLL in future clinical study. Disclosures Teshima: Novartis: Honoraria, Research Funding. Waldmann:Bioniz: Membership on an entity's Board of Directors or advisory committees. Staudt:Nanostring: Patents &amp; Royalties. Nakagawa:akeda Pharmaceutical Company Limited: Research Funding.

Understanding the Mechanisms Driving Genomic Instability in Adult T-Cell Leukemia/Lymphoma

Adult T-cell Leukemia/Lymphoma (ATLL) is a T-cell malignancy that results from infection by the retrovirus, human T cell lymphotropic virus-1 (HTLV-1). ATLL is endemic to Japan, the Caribbean regions and Latin America. Despite the rare occurrence of the disease, ATLL is a very aggressive malignancy with limited treatment options. Recent studies show that the ATLL patients diagnosed in North America (NA-ATLL), who are largely from the Caribbean region, have extremely poor prognosis as compared to the Japanese ATLL (J-ATLL) patients. A better understanding of the molecular pathogenesis of NA-ATLL is critical to identifying effective treatment measures for these patients. It has been previously shown that genomic instability including extensive chromosomal variations can be frequently found in ATLLs. However, the underlying mechanisms leading to this instability are unclear. Analysis of the mechanism of HTLV-1 action has revealed that the virus, in addition to hijacking the host cell machinery, disrupts DNA repair mechanisms and cell division processes. While the disruption of repair mechanisms could be held accountable for the accumulation of damage in ATLL cells, the precise nature of this disruption has not been fully understood. In proliferating cells, damage to the DNA occurs or is primarily recognized during DNA replication. This indicates that defective DNA replication could be an important factor driving genomic instability in ATLL cells. Possible involvement of replicative defects in the etiology of ATLL is further strengthened by the fact that genomic instability in ATLL cells has been shown to occur at difficult to replicate genomic regions referred to as common fragile sites. Here, using a powerful locus specific approach called the single molecule analysis of replicated DNA (SMARD), we show that perturbed DNA replication is an inherent component of disease manifestation in ATLL patients. Furthermore, our preliminary findings suggest that these changes in DNA replication can be largely attributed to the EP300 inactivating mutations often found among NA-ATLL patients. This study will help elucidate the molecular mechanisms contributing to the marked chemo-resistant feature of NA-ATLL patients, as compared to J-ATLL patients. In addition to increasing our understanding of the mechanisms contributing to ATLL in general, the results from this study may inform new and mechanism-based treatment paradigms that target the replicative defects of this unique disease. Disclosures No relevant conflicts of interest to declare.

S-Phase Progression of North American ATLL Cells Is Critically Regulated By the Proto-Oncogene BCL6 and Targetable By PARP Inhibition

Adult T-cell leukemia/lymphoma (ATLL) is a disease of malignant T cells that develops in human T-lymphotropic virus-1 (HTLV-1) carriers. ATLL is one of the most aggressive form of NHL with an abysmal survival and no promising targeted therapies. We and others have shown that ATLLs diagnosed in the Japanese (J-ATLL) and North American (NA-ATLL) patients have very different clinical behavior, with the NA-ATLL variant showing a more aggressive clinical course and carrying more frequent epigenetic mutations compared to J-ATLLs. The most frequently mutated epigenetic modifier gene in NA-ATLL is EP300 which is mutated in 20% of our patients compared to only 5.7% of J-ATLLs. EP300 encodes p300, a lysine acetyltransferase with a multitude of protein substrates including histone H3 and a number of important transcription factors, among which are p53 and BCL6. Previously, we have demonstrated that p300 mutations correlate with reduced p53 levels and compromised p53 transcriptional activity. In this study, we discovered for the first time that the B cell lymphoma oncogene BCL6 is expressed in primary ATLL samples and in vitro cultured ATLL cells. As expected, p300 mutation corresponds to reduced BCL6 acetylation. More importantly, notable differences in BCL6-regulated transcriptome were uncovered between EP300 WT and mutated samples based on RNA-seq analysis. Functional importance of BCL6 was then investigated using the siRNA-based knock-down approach in combination with a small compound BCL6 inhibitor, FX1. Unexpectedly, we discovered that nearly all cultured NA-ATLL samples are very sensitive to BCL6 inactivation (FX1 IC50 = 36+/-14 uM), while the 6 J-ATLL cell lines tested showed a wide range of FX1 sensitivity. This disparity is also seen in the pattern of BCL6-regulated genes. Specifically, based on clustering analysis, BCL6-regulated Reactome Pathways are more closely related among 4 NA-ATLL cell lines relative to those among 4 J-ATLL cell lines. Finally, we demonstrate that continued expression of BCL6 is critical for the survival of NA-ATLL cells going through the S-phase of cell cycle since the S-phase fraction was selectively depleted following BCL6 inactivation by either BCL6 siRNA transfection or FX1 treatment. Prompted by the recognition that the S-phase could be an "achilles heel" of NA-ATLL cells, we tested the sensitivity of a number of NA-ATLL samples (both primary and cell lines) and J-ATLL cell lines to 3 S-phase directed drugs: the PARP inhibitor, Olaparib, the Wee1 inhibitor, AZD-1775, and the ATR inhibitor, AZD-6738. While virtually all ATLL samples tested showed sensitivity to the Wee1 (IC50 = 0.2 to 1.1 uM) and ATR (IC50 = 1.0 to 14.5 uM) inhibitors, Olaparib sensitivity demonstrated ethnic and genotype specificity. Specifically, except the one and only EP300-mutated sample, 5/6 J-ATLL cell lines are resistant to Olaparib. In comparison, among the 10 NA-ATLL samples tested, 6/10 are Olaparib sensitive (IC50 =20-40 uM). The 4 Olaparib resistant samples carried inactivating mutations in either TP53 or RICTOR/PIK3CD. In summary, this study provides additional insights into the functional consequences of EP300 mutations in NA-ATLL. For the first time, we demonstrate that BCL6 is expressed in NA-ATLL and is critically required for survival of these cells when they transit through the S-phase of cell cycle. Furthermore, our discovery that NA-ATLLs are often sensitive to Olaparib treatment in vitro warrants follow up investigation that could lead to a novel targeted therapeutic strategy for this devastating malignancy. Disclosures Verma: Stelexis: Equity Ownership, Honoraria; Acceleron: Honoraria; Celgene: Honoraria; BMS: Research Funding; Janssen: Research Funding. Sica:Physician's Education Resources (PER): Honoraria.

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 < 70years 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.

Adult T-Cell Leukemia-Lymphoma.

Adult T-cell leukemia-lymphoma (ATL) is a peripheral T-lymphocyte malignancy caused by an RNA retrovirus, human T-cell leukemia virus type 1. ATL is clinically classified into four disease subtypes. The acute, lymphoma type, and cases of the chronic type involving unfavorable prognostic factors are regarded as aggressive ATL subtypes that require immediate treatment. Dose-intensified chemotherapy, such as the VCAP-AMP-VECP regimen, is considered to be the most recommended treatment for aggressive ATL. However, ATL remains difficult to cure and has an extremely poor prognosis, even when such chemotherapy is employed. Allogeneic stem cell transplantation is the only known curative therapy and is recommended for younger patients with aggressive ATL. However, because of the increasing age at the onset of ATL, only a small fraction of patients with ATL can benefit from such transplants; therefore, there is an unmet medical need for novel drugs. Mogamulizumab, a defucosylated, humanized anti-C-C motif chemokine receptor 4 (CCR4) monoclonal antibody, was developed using a novel glycoengineering technique. Mogamulizumab monotherapy achieved clinically meaningful effects in patients with relapsed aggressive ATL and has exhibited acceptable toxicity profiles both inside and outside of Japan. In addition, lenalidomide has shown promising antitumor activity in patients with ATL. Furthermore, based on the results of translational research, several promising novel agents are currently being investigated and might contribute to improving the prognosis of ATL.

The small molecule STF-62247 induces apoptotic and autophagic cell death in leukemic cells

Adult T cell leukemia/lymphoma (ATL) is an aggressive malignant T cell disease caused by human T cell leukemia virus-I (HTLV-1). Treatment outcomes for aggressive subtypes of ATL remain poor, with little improvement in overall survival since HTLV-1 was discovered. Therefore, new therapeutic strategies for ATL are required. STF-62247 induces autophagy and selectively kills renal cell carcinoma without apoptotic cell death. Here, we demonstrate that STF-62247 reduced cell viability and resulted in autophagosome accumulation and autophagy in leukemic cell lines (S1T, MT-2, and Jurkat). Interestingly, STF-62247 induced apoptosis in HTLV-1-infected cell lines (S1T and MT-2), as indicated by DNA fragmentation and caspase activation, but not in non-HTLV-1-infected Jurkat cells; a caspase inhibitor did not prevent this caspase-associated cell death. STF-62247 also increased nuclear endonuclease G levels. Furthermore, STF-62247 reduced cell viability and increased the number of apoptotic cells in peripheral blood mononuclear cells collected from patients with acute ATL, which has a poor prognosis. Therefore, STF-62247 may have novel therapeutic potential for ATL. This is the first evidence to demonstrate the cell growth-inhibitory effect of an autophagy inducer by caspase-dependent apoptosis and caspase-independent cell death via autophagy and endonuclease G in leukemic cells.

EPOCH regimen as salvage therapy for adult T-cell leukemia–lymphoma

Adult T-cell leukemia-lymphoma (ATL) is an intractable hematopoietic malignancy with a very poor prognosis. Although improved responses have been achieved through intensive chemotherapy in newly diagnosed patients with aggressive ATL, most patients suffer from relapse or disease recurrence, and an effective salvage therapy, especially for candidates for allogeneic hematopoietic stem cell transplantation (allo-HSCT), is yet to be established. The efficacy of the EPOCH regimen has been reported for several lymphoid malignancies; however, its efficacy for ATL has not been sufficiently evaluated. Here, we report results of a study of the EPOCH regimen as a salvage therapy for ATL. We retrospectively analyzed patients with relapsed or refractory ATL treated in our institution, with EPOCH as a first salvage therapy. Fourteen patients with a median age of 58years were analyzed, among whom eight achieved a response, including a complete response in one patient and partial responses in seven. Seven patients underwent allo-HSCT after EPOCH therapy; however, the median overall survival (OS) could not be determined, whereas OS at 2years after allo-HSCT was estimated to be 85.7%. These results suggest that EPOCH is an option for salvage therapy in patients with ATL, including candidates for allo-HSCT.

HTLV-1 Tax-Specific CTL Epitope-Pulsed Dendritic Cell Therapy Reduces Proviral Load in Infected Rats with Immune Tolerance against Tax.

Adult T cell leukemia/lymphoma (ATL), a CD4+ T cell malignancy with a poor prognosis, is caused by human T cell leukemia virus type 1 (HTLV-1) infection. High proviral load (PVL) is a risk factor for the progression to ATL. We previously reported that some asymptomatic carriers had severely reduced functions of CTLs against HTLV-1 Tax, the major target Ag. Furthermore, the CTL responses tended to be inversely correlated with PVL, suggesting that weak HTLV-1-specific CTL responses may be involved in the elevation of PVL. Our previous animal studies indicated that oral HTLV-1 infection, the major route of infection, caused persistent infection with higher PVL in rats compared with other routes. In this study, we found that Tax-specific CD8+ T cells were present, but not functional, in orally infected rats as observed in some human asymptomatic carriers. Even in the infected rats with immune unresponsiveness against Tax, Tax-specific CTL epitope-pulsed dendritic cell (DC) therapy reduced the PVL and induced Tax-specific CD8+ T cells capable of proliferating and producing IFN-γ. Furthermore, we found that monocyte-derived DCs from most infected individuals still had the capacity to stimulate CMV-specific autologous CTLs in vitro, indicating that DC therapy may be applicable to most infected individuals. These data suggest that peptide-pulsed DC immunotherapy will be useful to induce functional HTLV-1-specific CTLs and decrease PVL in infected individuals with high PVL and impaired HTLV-1-specific CTL responses, thereby reducing the risk of the development of ATL.

Adult T Cell Leukemia/Lymphoma in a 56 years Old Indian Male with History of Miliary Kochs on Anti-Tubercular Therapy

Adult T-cell leukemia/lymphoma (ATLL) is a rare T lymph proliferative disorder which is etiologically linked with human T-cell lymphotropic virus type-1 (HTLV-1). HTLV-1 is endemic in Japan, Caribbean and Africa. The highest incidence of ATLL is in Japan although sporadic cases have been reported elsewhere in the world. We describe a case of ATLL where a 56-year-old Indian male was referred to our hospital for increasing swelling on the left side of neck and thigh since last one month. Clinical examination revealed tender left cervical mass (150 mm by 90 mm) that was fixed, warm and slightly erythematous. A subcutaneous mass (40 mm by 35 mm) on the left thigh was non-tender and without erythema. Histopathological examination of the neck and thigh mass showed mixtures of intermediate and large atypical tumor cells. Immunohistochemical staining was positive for CD3, CD4 and CD8 and negative for CD29 and CD 79a, results that were consistent with T-cell lymphoma. Testing for antibody to human T-cell leukemia virus type 1 (HTLV-1) was positive.

Retargeting Oncolytic Vesicular Stomatitis Virus to Human T-Cell Lymphotropic Virus Type 1-Associated Adult T-Cell Leukemia.

ABSTRACTAdult T cell leukemia/lymphoma (ATL) is an aggressive cancer of CD4/CD25+ T lymphocytes, the etiological agent of which is human T-cell lymphotropic virus type 1 (HTLV-1). ATL is highly refractory to current therapies, making the development of new treatments a high priority. Oncolytic viruses such as vesicular stomatitis virus (VSV) are being considered as anticancer agents since they readily infect transformed cells compared to normal cells, the former appearing to exhibit defective innate immune responses. Here, we have evaluated the efficacy and safety of a recombinant VSV that has been retargeted to specifically infect and replicate in transformed CD4+ cells. This was achieved by replacing the single VSV glycoprotein (G) with human immunodeficiency virus type 1 (HIV-1) gp160 to create a hybrid fusion protein, gp160G. The resultant virus, VSV-gp160G, was found to only target cells expressing CD4 and retained robust oncolytic activity against HTLV-1 actuated ATL cells. VSV-gp160G was further noted to be highly attenuated and did not replicate efficiently in or induce significant cell death of primary CD4+ T cells. Accordingly, VSV-gp160G did not elicit any evidence of neurotoxicity even in severely immunocompromised animals such as NOD/Shi-scid, IL-2Rγ-c-null (NSG) mice. Importantly, VSV-gp160G effectively exerted potent oncolytic activity in patient-derived ATL transplanted into NSG mice and facilitated a significant survival benefit. Our data indicate that VSV-gp160G exerts potent oncolytic efficacy against CD4+ malignant cells and either alone or in conjunction with established therapies may provide an effective treatment in patients displaying ATL.IMPORTANCE Adult T cell leukemia (ATL) is a serious form of cancer with a high mortality rate. HTLV-1 infection is the etiological agent of ATL and, unfortunately, most patients succumb to the disease within a few years. Current treatment options have failed to significantly improve survival rate. In this study, we developed a recombinant strain of vesicular stomatitis virus (VSV) that specifically targets transformed CD4+ T cells through replacement of the G protein of VSV with a hybrid fusion protein, combining domains from gp160 of HIV-1 and VSV-G. This modification eliminated the normally broad tropism of VSV and restricted infection to primarily the transformed CD4+ cell population. This effect greatly reduced neurotoxic risk associated with VSV infection while still allowing VSV to effectively target ATL cells.

Preclinical efficacy of belinostat in combination with zidovudine in adult T-cell leukemia-lymphoma

Adult T-cell leukemia-lymphoma (ATLL) is an aggressive malignancy that is incurable by conventional drugs. Histone deacetylase (HDAC) inhibitors (HDIs) are broadly active anti-neoplastic agents that can be cautiously exploited in the treatment of ATLL. The HTLV-I provirus is clonally integrated in virtually all ATLL cells. The viral promoter is trans-activated by Tax protein through binding of CREB and p300/CBP at the 5'LTR. Tax binding enhances p300/CBP histone acetyl transferase (HAT) activity resulting in chromatin unwinding and transcription of the viral genome. Such HAT activity is countered by HDACs, and also by HBZ, which unlike Tax is the only viral gene consistently transcribed from the negative 3’ proviral strand end in ATLL. We recently conducted a clinical trial using the old generation HDI valproic acid (VPA) combined with zidovudine (AZT) and interferon alpha (IFNα) during maintenance therapy in patients with ATLL. We hypothesized that the HDI would reactivate HTLV-I thus provoking an immune response against circulating ATLL cells that normally persist after AZT/IFNα therapy. Supporting this notion adding VPA to AZT/IFNα resulted in HTLV-I proviral load reduction, followed by a molecular and prolonged clinical remission in one subject. We recently compared and tested more potent HDIs on primary ATLL cells and low-passage cell lines. In general, HDIs induced dose dependent Tax expression and apoptosis in ATLL cells, and provoked an intracellular innate immune response evidenced by the upregulation of IFN-B and IRF-7. The pan HDI belinostat caused H3 acetylation, blocked HBZ protein expression, and induced Tax protein expression in ATLL cells, while paradoxically inhibiting NF-κB nuclear activity, resulting in concomitant apoptosis. Further, adding AZT to belinostat augmented ATLL cell death. In contrast, IFNα treatment diminished apoptosis induced by belinostat. Based on these preclinical data, we proposed using belinostat in combination with AZT as consolidation therapy for ATLL. A pilot clinical trial is underway at our institution.

Prospective studies of allogeneic hema topoietic stem cell transplantation for adult T-cell leukemia-lymphoma

Adult T-cell leukemia-lymphoma (ATL) is divided into two types for decision of therapeutic strategy; aggressive variant includes acute, lymphoma and chronic type with poor prognostic factor, and indolent variant includes smoldering and chronic type without any factors. Prognosis of aggressive ATL by chemotherapy alone is very poor. We have reported the possibility of improvement of prognosis in aggressive ATL by allogeneic hematopoietic stem cell transplantation (allo-HSCT) for the first time in 2001, however transplant-related mortality (TRM) was very high. In order to reduce TRM and improve outcomes of aggressive ATL, we conducted prospective clinical trials of allo-HSCT using the reduced intensity conditioning (RIC). The first clinical trial (NST-1) was performed for evaluating allo-HSCT with RIC using HLA matched sibling donor in the patients of aggressive ATL aged over 50, and subsequently NST-2 trial was applied for the same eligibility. Conditioning regimen in NST-1 included busulfan, fludarabine and antithymocyte globulin (ATG), but omitted ATG in NST-2 because of early relapse. In all 29 patients registered in NST-1 and -2, 3-year and 5-year overall survival rates (OS) were 36% and 34% respectively. Eight patients were died of TRM. Ten of the 29 patients obtained long-term survival with good performance status. Subsequently, NST-3 trial was conducted with similar eligibility with NST-2 to confirm the efficacy of the therapeutic strategy of RIC. Twenty patients were transplanted and 2-year OS was 53%. The availability of sibling donors is becoming difficult mainly due to the aging of not only patients but also donors. Therefore, NST-4 trial was performed with similar eligibility using unrelated bone marrow (UBM) as alternative stem cell source. Fifteen patients were transplanted, we have confirmed the feasibility of UBM and 2-year OS was 67%. For the further improvement of allo-HSCT for aggressive ATL, the study using cord blood (NST-5) is on the way.

Phase I / II trial of dose adjusted EPOCH chemotherapy with bortezomib combined with integrase inhibitor therapy for HTLV-1 associated T-cell leukemia lymphoma

Adult T-cell leukemia lymphoma (ATLL) acute and lymphoma subtypes have a poor prognosis, with median survival of about one year. The malignant cells are characterized by high levels of nuclear factor kappa B (NFkappaB). In order to improve therapy, we assessed the safety, tolerance, and efficacy of a combination of dose-adjusted EPOCH chemotherapy (etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin), combined with proteasome inhibitor, bortezomib, to prevent degradation of the inhibitor of NFkappaB (IkappaB). In addition, integrase inhibitor, raltegravir, was added to the regimen to block virus replication occurring during treatment. This multicenter study enrolled 18 of 20 planned subjects over 2.5 yrs in the U.S., although 15 of the subjects were born in the Caribbean. Six subjects had acute ATLL, and the remainder lymphoma subtype, all but one with stage 4 disease. Therapy was well tolerated; subjects received 1-6 cycles of therapy (mean 4.5 cycles). Two subjects achieved complete remission lasting for >12 mos, 10 subjects had a partial remission, and 3 subjects had stable disease as their best response. Baseline calcium level, absolute lymphocyte count, and proviral DNA load were not predictive of response. Correlations with proviral expression, integration site, and integrase gene analyses will be presented. Supported by NIH grants CA94056, CA1730, CA63413, Lymphoma Leukemia Society grant 6067-10, and Lymphoma Research Foundation grant 307181203. Authors’ details Division of Oncology, Washington University, St Louis, MO, USA. University of Miami, Miami, FL, USA. Lymphoma & Hematology Division, Memorial Sloan Kettering Cancer Center, New York, NY, USA. Divisions of Hematology-Oncology, Montefiore Hospital, New York, NY, USA. Columbia University, New York, NY, USA. Division of Hematologic Malignancies, Johns Hopkins University, Baltimore, MD, USA. NINDS, NIH, Bethesda, MD, USA.

A rare presentation of adult T-cell leukemia/lymphoma with generalized cutaneous purpuric lesions

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive malignancy caused by human T-cell lymphotropic virus type 1. The disease is characterized by the presence of pleomorphic lymphocytes and cutaneous purpuric eruptions with skin, lymph node, visceral organs, central nervous system, and bone marrow involvement. We herein present the case of a 70-year-old man diagnosed with ATLL. The patient developed unique generalized cutaneous purpuric eruptions with systemic involvement including the gastrointestinal tract, peripheral blood, and bone marrow. Despite advanced chemotherapeutic treatment, he died about 5 months later due to a rapid progressive clinical course. Therefore, generalized cutaneous purpuric eruptions could be a poorer prognostic factor in the aggressive subtype of acute ATLL.

Adult T-Cell Leukemia/Lymphoma in a Caucasian Patient After Sexual Transmission of Human T-Cell Lymphotropic Virus Type 1.

Adult T-cell leukemia/lymphoma (ATLL), a T-cell neoplasm caused by human T-cell lymphotropic virus type 1 (HTLV-1), develops in the majority of cases in individuals who were infected with HTLV-1 as young children, by their mother during prolonged breastfeeding. We report the case of a Caucasian French man, whose parents were HTLV-1-seronegative and who developed ATLL after HTLV-1 sexual transmission by a Cameroonian woman. This hypothesis was corroborated by genotyping of the patient's virus, which revealed an HTLV-1B strain, found only in Central Africa, especially in Cameroon. Thus, ATLL may develop after HTLV-1 infection during adulthood, outside breastfeeding.