Treatment of adult T-cell leukemia/lymphoma: past, present, and future

Stem cell therapy for HTLV-1 induced adult T-cell leukemia/lymphoma (ATLL): A comprehensive review

Adult T-cell leukemia/lymphoma (ATLL) is a rare and aggressive form of cancer associated with human T-cell lymphotropic virus type 1 (HTLV-1) infection. The emerging field of stem cell therapies for ATLL is discussed, highlighting the potential of hematopoietic stem cell transplantation (HSCT) and genetically modified stem cells. HSCT aims to eradicate malignant T-cells and restore a functional immune system through the infusion of healthy donor stem cells. Genetically modified stem cells show promise in enhancing their ability to target and eliminate ATLL cells. The article presents insights from preclinical studies and limited clinical trials, emphasizing the need for further research to establish the safety, efficacy, and long-term outcomes of stem cell therapies for ATLL and challenges associated with these innovative approaches are also explored. Overall, stem cell therapies hold significant potential in revolutionizing ATLL treatment, and ongoing clinical trials aim to determine their benefits in larger patient populations.

Therapeutic approaches for HTLV-1-associated adult T-cell leukemia/lymphoma: a comprehensive review

Adult T-cell leukemia/lymphoma (ATLL), an infrequent malignancy resultant from human T-cell lymphotropic virus type I (HTLV-1), exhibits a spectrum of phenotypes, encompassing acute, smoldering, lymphomatous, and chronic variants, each bearing distinct clinical presentations. The preponderant acute manifestation is characterized by hypercalcemia, systemic manifestations, organomegaly, and dermatological eruptions. Conversely, the chronic phenotype is typified by lymphocytosis and/or cutaneous eruptions, while smoldering ATLL assumes an asymptomatic course. Immunocompromise afflicts ATLL patients, heightening their vulnerability to opportunistic infections that frequently intricately intertwine with disease progression. Therefore, an early diagnosis is crucial to manage the disease appropriately. While conventional chemotherapeutic regimens have shown limited success, especially in acute and lymphoma types, recent studies suggest that allogeneic stem cell transplantation might enhance treatment results because it has shown promising outcomes in some patients. Novel therapeutics, such as interferon and monoclonal antibodies, have also shown promise, but more research is needed to confirm their efficacy. Moreover, the identification of biomarkers for ATLL and genetic changes in HTLV-1 infected cells has led to the development of targeted therapies that have shown remarkable success in clinical trials. These targeted therapies have the potential to offer a more personalized approach to the treatment of ATLL. The aim of our review is to elaborate on conventional and novel therapies and the efficiency of mentioned treatments.

Screening of promising chemotherapeutic candidates from plants against human adult T-cell leukemia/lymphoma (VIII): six new withanolides from Physalis philadelphica

Adult T-cell leukemia/lymphoma (ATL) is a malignancy of mature peripheral T-lymphocytes caused by human T-cell leukemia virus type I (HTLV-I). There are an estimated 5-20 million HTLV-1-infected individuals worldwide. Conventional chemotherapeutic regimens used against other malignant lymphomas have been administered to patients with ATL, but the therapeutic outcomes of acute and lymphoma-type ATL remain extremely poor. In the course of our screening program for novel chemotherapeutic candidate compounds from plants against two human T-cell leukemia virus I-infected T-cell lines (MT-1 and MT-2), we screened 16 extracts obtained from different parts of 7 Solanaceae plants. We identified that the extracts of Physalis pruinosa and P. philadelphica showed potent anti-proliferative activity in MT-1 and MT-2 cells. In our previous study, we have isolated withanolides from extract of aerial parts of P. pruinosa and examined their structure-activity relationships. In addition, we are also investigating further structure-activity relationships about other withanolides from Solanaceae plants (Withania somnifera, Withania coagulans, Physalis angulate, Nicandra physalodes, Petunia hybrida, and Solanum cilistum). In this study, we attempted to isolate their active compounds against MT-1 and MT-2 from extracts of P. philadelphica. We identified 13 withanolides, including six newly isolated compounds [24R, 25S-4β, 16β, 20R-trihydroxy-1-oxowitha-2-en-5β, 6 β -epoxy-22,26-olide (1), 4β, 7β,20R-trihydroxy-1-oxowitha-2-en-5β, 6β -epoxy-22,26-olide (2), 17β,20 S-dihydroxywithanone (3), 2,3-dihydro-3β-methoxy-23β-hydroxywithaphysacarpin (4), 3-O-(4-rhamnosyl)glucosyl-physalolactone B (5), and 17R, 20R, 22S, 23S, 24R, 25R-4β, 5α, 6β, 20β, 22α -tetrahydroxy-16β, 23-diepoxy-1-oxowitha-2-en-26, 23-olide (6)], from the extract and examined the structure-activity relationships. The 50% effective concentration of withaphysacarpin (compound 7) [MT-1: 0.10 µM and MT-2: 0.04 µM] was comparable to that of etoposide [MT-1: 0.08 µM and MT-2: 0.07 µM]. Therefore, withanolides might be promising candidates for the treatment of ATL.

Screening of Promising Chemotherapeutic Candidates from Plants against Human Adult T-Cell Leukemia/Lymphoma (VII): Active Principles from Thuja occidentalis L

During the screening of novel chemotherapeutic candidates from plants against adult T-cell leukemia/lymphoma, we identified that the extracts of Thuja occidentalis (Cupressaceae) showed potent anti-proliferative activity in MT-1 and MT-2 cells. Therefore, we attempted to isolate the active components from this plant. We isolated and identified 32 compounds (1-32; eight lignans, 18 terpenoids, and six flavonoids) from the extracts of the leaves and cones. Their structures were determined by spectroscopic analysis. Several of the isolated compounds inhibited the growth of both cell lines. Lignans showed more potent activity than other classes of compounds. A comparison of the activities of compounds 1-8 revealed that the presence of a trans-lactone (linkage of C-6 to C-7) correlated with increased activity. Diterpenes showed moderate activity, and the presence of a ketone moiety at the C-7 position correlated with increased activity in compounds 12-21. In addition, biflavones showed moderate activity, and the presence of methoxy functions appeared to influence the activity of these compounds. Several lignans were lead compound of anti-cancer reagent (etoposide). In conclusion, not only lignans, but also diterpenes and/or biflavones, may be promising candidates for the treatment of adult T-cell leukemia/lymphoma.

Targeting NF-κB with Nanotherapy in a Mouse Model of Adult T-Cell Leukemia/Lymphoma

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive, clonal malignancy of mature T cells caused by human T-cell leukemia virus type 1. Although it is a rare tumor type, it serves as an excellent model of a virus driven process that transforms cells and engenders a highly malignant tumor that is extraordinarily difficult to treat. The viral transcriptional transactivator (Tax) in the HTLV-1 genome directly promotes tumorigenesis, and Tax-induced oncogenesis depends on its ability to constitutively activate NF-κB signaling. Accordingly, we developed and evaluated a nano-delivery system that simultaneously inhibits both canonical (p65) and noncanonical (p100) NF-κB signaling pathways locally in tumors after systemic administration. Our results demonstrate that siRNA is delivered rapidly to ATLL tumors after either i.p. or i.v. injection. The siRNA treatment significantly reduced both p65 and p100 mRNA and protein expression. Anti-NF-κB nanotherapy significantly inhibited tumor growth in two distinct tumor models in mice: a spontaneous Tax-driven tumor model, and a Tax tumor cell transplant model. Moreover, siRNA nanotherapy sensitized late-stage ATLL tumors to the conventional chemotherapeutic agent etoposide, indicating a pleiotropic benefit for localized siRNA nanotherapeutics.

Orbital and Ocular Adnexal Manifestations of Adult T-Cell Leukemia/Lymphoma: a Case Report and Systematic Review

PURPOSE

To describe a patient with orbital adult T-cell leukemia/lymphoma (ATLL) and to review the literature on presentation, diagnostics, management, and clinical course of this rare disease.

METHODS

A systematic literature review. PubMed/MEDLINE and Google Scholar databases were searched for all well-documented cases of orbital/ocular adnexal ATLL.

RESULTS

Sixteen patients were included in the final analysis. The median age at diagnosis was 47 years (range, 20-85), 9/16 patients (56%) were male, and patients were of Japanese (10/16, 63%), Caribbean (5/16, 31%), or African (1/16, 6%) origin. Proptosis (6/15, 40%) and visual loss (5/15, 33%) were the most common presenting signs. Involvement of adjacent structures was documented in 8 of 16 (50%) patients. All patients had evidence of systemic ATLL, which was identified concurrently with orbital/ocular adnexal disease in 9 of 15 (60%) patients. Management included multi-agent chemotherapy with steroids (9/13, 69%), antivirals (2/13, 15%), biologic agents (4/13, 31%), and umbilical cord blood transplantation (1/13, 8%). Most patients (8/12, 67%) experienced at least partial remission with disease relapse occurring in 6 of 8 patients (75%). The median survival time was 28 months (95% CI, 5.5-50.5 months).

CONCLUSIONS

Adult T-cell leukemia/lymphoma should be considered in the differential diagnosis of orbital and ocular adnexal space-occupying lesions, particularly in male patients from endemic regions. Orbital disease is frequently locally aggressive and presents concurrently with systemic ATLL, highlighting the importance of comprehensive multimodal work-up and multidisciplinary management. Emerging targeted therapies and hematopoietic stem cell transplant may prolong survival.

HTLV-1 infection of myeloid cells: from transmission to immune alterations

Human T cell leukemia virus type 1 (HTLV-1), the etiological agent of adult T-cell leukemia/lymphoma (ATLL) and the demyelinating neuroinflammatory disease known as HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), was the first human retrovirus to be discovered. T-cells, which represent the main reservoir for HTLV-1, have been the main focus of studies aimed at understanding viral transmission and disease progression. However, other cell types such as myeloid cells are also target of HTLV-1 infection and display functional alterations as a consequence. In this work, we review the current investigations that shed light on infection, transmission and functional alterations subsequent to HTLV-1 infection of the different myeloid cells types, and we highlight the lack of knowledge in this regard.

Clinical Features, Pathological Features, and Treatment Outcomes of 22 Patients with Aggressive Adult T-cell Leukemia-lymphoma Treated with a Humanized CCR4 Antibody (Mogamulizumab) at a Single Institution during a 6-year Period (2012-2018)

Objective To elucidate the clinical impact of humanized CCR4 antibody (mogamulizumab) on adult T-cell leukemia-lymphoma (ATL), we retrospectively analyzed the clinical and pathological features and treatment outcomes of aggressive ATL. Methods Twenty-two patients (median age: 65 years) with aggressive ATL [acute- (n=16) or lymphoma-type (n=6)] had their characteristics analyzed. All cases were treated with mogamulizumab at our institution from 2012 to 2018. In addition, we subjected 14 specimens of ATL to histological, immunological, and genetic analyses. Results Regarding the patient outcomes, the overall response rates were 68.1% and 31.8% after 4 and 8 courses (or after the final courses), respectively. The median overall survival (OS) was 95.5 days, while the OS rates at 6 and 12 months were 31.5% and 21.1%, respectively. Concerning patient pathological characteristics, 6 of the 14 patients examined (42.9%) had CCR4 mutations. Regarding the clinicopathological findings related to the mogamulizumab response, notably, the cases with somatic CCR4 mutation tended to have a poorer response (16.7%) than those with wild-type CCR4 (62.5%) after 4 cycles of mogamulizumab. Furthermore, the CCR4 global score tended to be higher in the responder cases than in the non-responder cases. Conclusion The present findings suggest that the CCR4 expression may be related to the mogamulizumab response, although no other significant predictive markers were identified in this study. Further studies will be needed in order to identify more markers related to the mogamulizumab response.

Phosphatidylinositol 3-kinase-δ (PI3K-δ) is a potential therapeutic target in adult T-cell leukemia-lymphoma

The prognosis of adult T-cell leukemia-lymphoma (ATL) remains very poor, and there is an urgent clinical need to investigate novel therapies for ATL. The expression of phosphatidylinositol 3-kinase-δ (PI3k-δ) is normally restricted to hematopoietic cells and is known as a key determinant of cell survival in certain cancers. The inhibitor of PI3k-δ, idelalisib, has been shown to be effective in the treatment of chronic lymphocytic leukemia. Here, we report the expression of PI3k-δ and the ability of idelalisib to promote apoptosis in ex vivo ATL samples. The activity of PI3K was quantified by a PI3-Kinase Activity ELISA kit. Although there was no significant difference in mean PI3K activity between healthy donors and patients with ATL, certain cases of ATL showed extremely high PI3K activities. The expression of PI3k-δ protein was detectable in most ATL cases. The freshly isolated cells from ATL patients were cultured with or without idelalisib for 0–10 days, and cell survival was then quantified. Idelalisib induced apoptosis in ATL cells in a time-dependent manner, and significantly reduced the frequency of viable ATL cells at 10 days. No time-dependent effects of idelalisib were observed in non-malignant T cells from the same patients. CCL22 has been reported to promote survival of ATL cells in part through the PI3K-AKT pathway. Idelalisib blocked this CCL22-induced phosphorylation of AKT and significantly inhibited the proliferation of ATL cells. These results validate the PI3K-AKT pathway as a potential therapeutic target in ATL.

IFI16 regulates HTLV-1 replication through promoting HTLV-1 RTI-induced innate immune responses

Interferon (IFN)-inducible protein 16 (IFI16) regulates human immunodeficiency virus replication by inducing innate immune responses as a DNA sensor. Human T-lymphotropic virus type 1 (HTLV-1), a delta retrovirus family member, has been linked to multiple diseases. Here, we report that IFI16 expression is induced by HTLV-1 infection or HTLV-1 reverse transcription intermediate (RTI) ssDNA90 transfection. IFI16 overexpression decreases HTLV-1 protein expression, whereas IFI16 knockdown increases it. Furthermore, the knockdown of IFI16 is followed by impaired innate immune responses upon HTLV-1 infection. In addition, IFI16 forms a complex with ssDNA90 and enhances ssDNA90-triggered innate immune responses. Collectively, our data suggest a critical role for IFI16 during HTLV-1 infection by interacting with HTLV-1 RTI ssDNA90 and restricting HTLV-1 replication.

The Effects of Ultrasound and Arsenic Trioxide on Neurogliocytoma Cells and Secondary Activation of Macrophages

Aims and Background

As a new technique for clinical therapeutics, ultrasound has synergistic effects on traditional chemotherapy. Arsenic trioxide (AS2O3), an apoptosis-inducing drug, has successfully been used in the treatment of some tumor types in recent years. Macrophages have both positive and negative effects on the occurrence and development of tumors. The aim of this study was to observe the effects of ultrasound and AS2O3 on a glioma cell line and the secondary activation of macrophages by cell death, in order to provide a theoretical basis for the clinical application of AS2O3 and ultrasound in glioma treatment.

Methods

Different AS2O3 concentrations were used solely or combined with ultrasound in rat glioma C6 cells to induce cell death. The degree of C6 cell death was determined by AnnexinV-FITC and PI double staining. The intracellular arsenium concentration and the release of lactate dehydrogenase (LDH) from C6 cells were also measured. The supernatant of C6 cells was then used to stimulate macrophages. Finally the activation of NF-κB and the secretion of TNF-α and TGF-β1 by macrophages were determined.

Results

The cell death increase in the group where ultrasound was used together with AS2O3 was significantly higher than that obtained by either ultrasound or AS2O3. The increase was also significantly higher than the sum of the increases in the ultrasound and the AS2O3 only groups. At the same AS2O3 concentration, additional treatment with ultrasound can significantly increase the intracellular arsenium concentration. The release of LDH from C6 cells showed a close, direct correlation with late apoptosis and necrosis, but did not exhibit an obvious correlation with early apoptosis. The activation of NF-κB and the secretion of TNF-α and TGF-β1 in macrophages also showed a close direct correlation with late apoptosis and necrosis.

Conclusions

This in vitro study demonstrates that ultrasound may synergistically enhance the cell-killing effect by promoting AS2O3 to enter the C6 cells. Macrophages may be activated by killed C6 cells, especially by necrotic C6 cells.

The Impact of a Humanized CCR4 Antibody (Mogamulizumab) on Patients with Aggressive-Type Adult T-Cell Leukemia-Lymphoma Treated with Allogeneic Hematopoietic Stem Cell Transplantation

Although a humanized CCR4 antibody (mogamulizumab) was reported to be effective for refractory adult T-cell leukemia-lymphoma (ATL), several reports regarding the use of mogamulizumab before allo-hematopoietic stem cell transplantation (HSCT) strongly indicated a high incidence of severe acute graft-versus-host-disease (GVHD) and treatment-related mortality (TRM). We retrospectively analyzed nine aggressive-type ATL patients who underwent allo-HSCT at a single institution in Miyazaki from 2006.1.1 to 2015.7.31. Among nine ATL patients, three had used mogamulizumab before treatment with allo-HSCT because of the poor control of refractory ATL. All three patients were treated with four to eight cycles of mogamulizumab. The interval from last administration of mogamulizumab to allo-HSCT was two to five months. All three patients with prior mogamulizumab treatment developed mild-moderate acute GVHD (grade 2) 28, 34, or 40 days after allo-HSCT. Acute GVHD was controlled by prednisolone treatment. Two patients in complete remission before allo-HSCT exhibited relatively prolonged survival (survival rate, 66%). Moreover, one patient developed human T-cell leukemia virus type 1-associated myelopathy-mimicking myelitis at five months after allo-HSCT. In contrast, two of six ATL patients without a history of mogamulizumab use survived (survival rate 33%). Thus, in cases of mogamulizumab use before treatment with allo-HSCT for refractory ATL, an appropriately long interval from the last administration of mogamulizumab to allo-HSCT may be one of factors to reduce TRM by acute GVHD, and to subsequently enhance graft-versus-tumor effects in ATL cases. Furthermore, caution is needed when administering mogamulizumab before allo-HSCT for severe GVHD and TRM.

Screening of promising chemotherapeutic candidates from plants against human adult T-cell leukemia/lymphoma (V): coumarins and alkaloids from Boenninghausenia japonica and Ruta graveolens

During the course of our studies towards the identification of promising chemotherapeutic candidates from plants against two human T-cell lymphotropic virus type I-infected T-cell lines (MT-1 and MT-2), we screened 17 extracts from 9 rutaceous plants against MT-1 and MT-2 cells. The extracts from the aerial parts and roots of Boenninghausenia japonica, as well as the leaves and roots of Ruta graveolens showed potent antiproliferative effects. After activity-guided fractionation, we isolated 44 compounds from two rutaceous plants, including three new compounds (1-3), which were classified into 26 coumarin analogs (13 coumarins, 8 furanocoumarins, 4 dihydrofuranocoumarins and one dihydropyranocoumarin), 15 alkaloid analogs (7 quinolone alkaloids, 4 acridone alkaloids, 3 furanoquinoline alkaloids and one tetrahydroacridone alkaloid) and 3 flavonoid glycosides. Structure-activity relationship studies were also evaluated. The coumarin compounds (2, 3 and 7-9) bearing a 3-dimethylallyl moiety showed potent activity. Similarly, of all the furanocoumarins evaluated in the current study, compound 17 bearing a 3-dimethylallyl group also showed potent activity. A dihydrofuranocoumarin (27) bearing a 3-dimethylallyl moiety showed the most potent activity. Following 27, compound 28 showed potent activity. These results therefore suggested that the presence of a 3-dimethylallyl moiety was important to the antiproliferative activity of these coumarin analogs.

Treatment of adult T-cell leukemia

Adult T-cell Leukemia (ATL) is an aggressive malignant disease of CD4+ T-cells associated with human T-cell leukemia virus type I (HTLV-I). Prognosis of ATL patients is directly correlated to the subtype of ATL. Treatment of the aggressive forms (acute and lymphoma types) of ATL remains inadequate, as most ATL patients receive conventional chemotherapy without stem cell rescue. At present, LSG15 is the standard chemotherapy for the treatment of aggressive ATL, but the efficacy of LSG15 in most patients is transient. To prolong median survival time, additional therapies for maintenance of complete response (CR) are needed after achieving CR by induction chemotherapy. Improved outcome after allogeneic stem cell transplantation (allo-SCT), despite a high incidence of graft-versus-host disease, has been reported. Thus, allogeneic bone marrow transplantation and allogeneic peripheral blood SCT may have great potential for eradication of HTLV-1 and cure of ATL. Recently, reduced-intensity conditioning stem cell transplantation was also reported to be effective for ATL. Although several issues, including selection criteria for patients and sources of stem cells remain to be resolved, allo-SCT may be considered as a treatment option for patients with aggressive ATL. To evaluate whether allo-SCT is more effective than the standard chemotherapy (LSG15) for aggressive ATL, an up front phase II clinical trial of JCOG-LSG is now being planned. Novel innovative targeted strategies, such as antiretroviral therapy, arsenic trioxide, nuclear factor-kappaB inhibitors, proteasome inhibitors, histone deacetylase inhibitors, several monoclonal antibodies including anti-CC chemokine receptor 4, anti-folate, purine nucleotide phosphorylase inhibitor, mTOR (mammalian target of rapamycin) inhibitor, bendamustine, small molecule Bcl-2 inhibitors and Tax-targeted immunotherapy, should be promptly studied in order to develop curative treatments for ATL in the near future.

Clinical Impact of a Humanized CCR4 Antibody (Mogamulizumab) in 14 Patients with Aggressive Adult T-cell Leukemia-lymphoma Treated at a Single Institution During a Three-year Period (2012-2014)

Objective We elucidated the effectiveness of a humanized CCR4 antibody (mogamulizumab) on adult T-cell leukemia-lymphoma (ATL), which typically has a poor outcome. Methods We retrospectively analyzed 14 patients with aggressive ATL who had been treated at our institution with weekly cycles of mogamulizumab for eight weeks from 2012-2014. Results The patients (median age: 63 years old) were classified as having acute- (n=10) or lymphoma-type (n=4) ATL. The prior treatment regimens consisted of CHOP, VCAP-AMP-VECP, DeVIC and CHASE, with an average of two courses (range: 1-4). The prior disease responses were partial remission (n=3) and progressive disease (n=11). The treatment was administered in the primary refractory setting (n=8), for relapse (n=2), or as bridging therapy before hematopoietic stem cell transplantation (n=4). The overall response rates were 64% and 43% after four and eight cycles (or after the final cycles), respectively. The median overall survival (OS), OS rate at six months and OS rate at 12 months were 66 days, 41.7% and 20.8%, respectively. All of the patients with acute-type ATL who showed a response to treatment had an early response. Notably, six of the 14 ATL patients showed somewhat prolonged survival (>100 days). However, relapse or disease progression in the peripheral blood, central nervous system, lymph nodes, skin, and/or bone occurred within a relatively short period after treatment. The adverse effects were tolerable, and included lymphopenia, cytomegalovirus infection and skin rash. Conclusion Mogamulizumab therapy resulted in an early and high remission rate and somewhat prolonged survival in patients with refractory ATL. However, the duration of remission was short, and there was early relapse and disease progression. This study may show the current impact of mogamulizumab in clinical practice.

Clinical Features and Treatment Outcomes of 81 Patients with Aggressive Type Adult T-cell Leukemia-lymphoma at a Single Institution over a 7-year Period (2006-2012)

OBJECTIVE

Despite the remarkable advances in chemotherapy and allogeneic hematopoietic stem cell transplantation (HSCT), adult T-cell leukemia-lymphoma (ATL) is still associated with a high mortality rate. It is therefore essential to elucidate the current features of ATL.

METHODS

We retrospectively analyzed 81 patients with aggressive type ATL at our institution over a 7-year period based on Shimoyama's diagnostic criteria.

RESULTS

Eighty-one patients with a median age of 67.5 years were classified as having acute (n=47), lymphoma (n=32), or chronic type (n=2) ATL. They were initially treated by either palliative therapy (n=25) or systemic chemotherapy [n=56; cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) therapy (n=25)/vincristine, cyclophosphamide, doxorubicin, and prednisone (VCAP)-doxorubicin, ranimustine, and prednisone (AMP)-vindesine, etoposide, carboplatin, and prednisone (VECP) therapy (VCAP-AMP-VECP) or CHOP-VMMV therapy (n=31)], and showed median survival durations of 16 and 277 days, respectively. Subsequent to the initial treatment, HSCT (n=6) was performed for certain patients, thus revealing that two-thirds (n=4) relapsed, and one-third (n=2) survived for 131 days and 203 days, respectively. The relapsed ATL patients were treated with conventional salvage therapy (n=29) or anti-CC chemokine receptor 4 antibody (mogamulizumab) (n=3). The patients treated with mogamulizumab demonstrated complete response (2) and partical response (1) with short duration periods of 82 days, 83 days, and 192 days, respectively. Among the five long-term survivors (>5 years) who received chemotherapy, most showed a low and intermediate risk according to the ATL prognostic index.

CONCLUSION

In our study, the overall survival of ATL remains poor due to the advanced age of the patients at diagnosis, a high proportion of patients receiving palliative therapy, and a small proportion of long-term survivors receiving chemotherapy and undergoing HSCT. This study illustrates the current clinical features, treatment strategies, and outcomes in clinical practice.

Quantification of the effect of chemotherapy and steroids on risk of Pneumocystis jiroveci among hospitalized patients with adult T-cell leukaemia

This study aimed to quantify the risks of Pneumocystis pneumonia (PCP) among adult T-cell leukaemia (ATL) patients without prophylaxis. We used hospital administrative data collected nationwide in Japan over 4 years. The research design was a retrospective cohort study. Subjects were 4369 patients diagnosed with ATL aged 18 years or older. The subjects were categorized into four treatment groups: no agent, chemotherapy, chemotherapy + steroids and steroids. We described the risks of PCP among ATL patients without prophylaxis. Risks of PCP were 3·2% for the no agent group, 9·7% for the chemotherapy group, 10·0% for the chemotherapy + steroids group and 16·6% for the steroids group. Logistic regression analyses showed that the chemotherapy, chemotherapy + steroids and steroids groups had significantly higher risk of PCP than did the no agent group [adjusted odds ratio (AOR) 3·30 (1·55-7·02), P = 0·002 for the chemotherapy group; AOR 3·35 (2·18-5·17), P < 0·001 for the chemotherapy + steroids group; AOR 6·12 (3·99-9·38), P < 0·001 for the steroids group]. In conclusion, the chemotherapy, chemotherapy + steroids and steroids groups had significantly higher risks of PCP. Prophylaxis for PCP among ATL patients being treated with chemotherapy, chemotherapy + steroids and steroids is highly recommended.

Development of peripheral T-cell lymphoma not otherwise specified in an HTLV-1 carrier

Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia (ATL) after a long latency period of about 60 years. As the mature T-cell neoplasms that emerge in patients infected with HTLV-1 are often ATL, T-cell neoplasms developing in such patients tend to be diagnosed simply as ATL without further investigation. However, not all T-cell neoplasms that develop in HTLV-1-infected cases are ATL. Mature T-cell malignancies other than ATL should be carefully excluded in patients infected with HTLV-1, as these sometimes closely resemble ATL in their clinical, morphological, and histological features. Here, we present a case of peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) in an HTLV-1 carrier. Confirmation of monoclonal integration of the virus with Southern blotting leads to a definite diagnosis of ATL. Although we did not detect the monoclonal integration band of HTLV-1 in this case, the high HTLV-1 proviral load complicated the diagnosis. Multicolor flow cytometric analysis clearly showed that HTLV-1 was not integrated in the tumor cells, and facilitated discrimination of PTCL-NOS from ATL.

Screening of promising chemotherapeutic candidates from plants against human adult T-cell leukemia/lymphoma (III)

Adult T-cell leukemia/lymphoma (ATL) is a malignancy of mature peripheral T lymphocytes caused by human T-cell lymphotropic virus type I (HTLV-I). In our previous paper, 214 extracts from 162 plants were screened to elucidate the anti-proliferative principles against HTLV-I-infected T-cell lines. In this study, 245 extracts from 182 plants belonging to 61 families were further tested against two HTLV-I-infected T-cell lines (MT-1 and MT-2). Potent anti-proliferative effects were exhibited against MT-1 and MT-2 cells by 52 and 60 of the 245 extracts tested, respectively. Of these, two extracts showed strong inhibitory activity (EC₅₀ values 0.1-1 μg/mL; +++) against both cells, 7 extracts showed moderate inhibitory activity (EC5₅₀ values 1-10 μg/mL; ++), and 43 extracts showed weak inhibitory activity (EC₅₀ values 10-100 μg/mL; +), whereas the remaining extracts did not show any activity (EC₅₀ values >100 μg/mL; -) against MT-1 cells. On the other hand, 10 extracts showed moderate inhibitory activit and, 48 extracts showed weak inhibitory activity, whereas the remaining extracts did not show any activity against MT-2 cells. Extracts from the aerial parts of Annona reticulata and A. squamosa showed the most potent inhibitory activity and three aporphine alkaloids were isolated from their extracts as the active principles by activity-guided fractionation.

Markedly additive antitumor activity with the combination of a selective survivin suppressant YM155 and alemtuzumab in adult T-cell leukemia

Adult T-cell leukemia (ATL) is an aggressive malignancy of CD4(+)CD25(+) lymphocytes caused by human T-cell lymphotropic virus type 1. Currently, there is no accepted curative therapy for ATL. In gene expression profiling, the antiapoptotic protein survivin (BIRC5) demonstrated a striking increase in ATL, and its expression was increased in patient ATL cells resistant to the anti-CD52 monoclonal antibody alemtuzumab (Campath-1H). In this study, we investigated the antitumor activity of a small-molecule survivin suppressant YM155 alone and in combination with alemtuzumab in a murine model of human ATL (MET-1). Both YM155 alone and its combination with alemtuzumab demonstrated therapeutic efficacy by lowering serum soluble IL-2Rα (sIL-2Rα) levels (P < .001) and prolonged the survival of tumor-bearing mice (P < .0001). Moreover, the combination of YM155 with alemtuzumab demonstrated markedly additive antitumor activity by significantly lowering serum sIL-2Rα levels and improving the survival of leukemia-bearing mice compared with monotherapy with either YM155 (P < .001) or alemtuzumab (P < .05). More significantly, all mice that received the combination therapy survived and were tumor free >6 months after treatment. Our data support a clinical trial of the combination of YM155 with alemtuzumab in ATL. This trial was registered at www.clinicaltrials.gov as #NCT00061048.

Lymphomas and leukemias due to infectious organisms

World-wide, approximately 25% of all human malignancies are caused by infectious organisms, including approximately 10% of cancers occurring in resource rich areas of the world. While some of these disorders are more likely to be seen in patients with underlying immunodeficiency, this is not a requisite for development of malignancy, and most patients, in fact, are not immune-suppressed at the time of diagnosis. In considering hematologic malignancies, several organisms have been implicated in disease etiology. These organisms include Human Herpesvirus 8 (HHV8/KSHV), which is linked to primary effusion lymphoma and to multicentric Castleman s disease, as well as to development of Kaposi's sarcoma; Epstein Barr Virus (EBV) which has been associated with Burkitt lymphoma and nasal T cell lymphoma, among others; Human T lymphotrophic virus type I (HTLV 1), which is associated with Adult T cell leukemia/lymphoma (ATLL); Hepatitis C virus, associated with splenic marginal and other lymphomas; and Helicobacter pylori, associated with gastric MALT lymphoma. The presentation will focus on the latter three disorders, describing pathogenesis of disease, clinical manifestations and therapeutic options.

Prognostic Index for Acute- and Lymphoma-Type Adult T-Cell Leukemia/Lymphoma

Purpose

The prognosis of acute- and lymphoma-type adult T-cell leukemia/lymphoma (ATL) is poor, but there is marked diversity in survival outcomes. The aim of this study was to develop a prognostic index (PI) for acute- and lymphoma-type ATL (ATL-PI).

Patients and Methods

In a retrospective review, data from 807 patients newly diagnosed with acute- and lymphoma-type ATL between January 2000 and May 2009 were evaluated. We randomly divided subjects into training (n = 404) and validation (n = 403) samples, and developed a PI using a multivariable fractional polynomial model.

Results

Median overall survival time (MST) for the 807 patients was 7.7 months. The Ann Arbor stage (I and II v III and IV), performance status (0 to 1 v 2 to 4), and three continuous variables (age, serum albumin, and soluble interleukin-2 receptor [sIL-2R]) were identified as independent prognostic factors in the training sample. Using these variables, a prognostic model was devised to identify different levels of risk. In the validation sample, MSTs were 3.6, 7.3, and 16.2 months for patients at high, intermediate, and low risk, respectively (P < .001; χ2 = 89.7, 2 df; log-rank test). We also simplified the original ATL-PI according to dichotomizing age at 70 years, serum albumin at 3.5 g/dL, and sIL-2R at 20,000 U/mL and developed an easily calculable PI with prognostic discrimination power (P < .001; χ2 = 74.2, 2 df; log-rank test).

Conclusion

The ATL-PI is a promising new tool for identifying patients with acute- and lymphoma-type ATL at different risks.

Pediatric T- and NK-cell lymphomas: new biologic insights and treatment strategies

T- and natural killer (NK)-cell lymphomas are challenging childhood neoplasms. These cancers have varying presentations, vast molecular heterogeneity, and several are quite unusual in the West, creating diagnostic challenges. Over 20 distinct T- and NK-cell neoplasms are recognized by the 2008 World Health Organization classification, demonstrating the diversity and potential complexity of these cases. In pediatric populations, selection of optimal therapy poses an additional quandary, as most of these malignancies have not been studied in large randomized clinical trials. Despite their rarity, exciting molecular discoveries are yielding insights into these clinicopathologic entities, improving the accuracy of our diagnoses of these cancers, and expanding our ability to effectively treat them, including the use of new targeted therapies. Here, we summarize this fascinating group of lymphomas, with particular attention to the three most common subtypes: T-lymphoblastic lymphoma, anaplastic large cell lymphoma, and peripheral T-cell lymphoma-not otherwise specified. We highlight recent findings regarding their molecular etiologies, new biologic markers, and cutting-edge therapeutic strategies applied to this intriguing class of neoplasms.

Differential role of PKC-induced c-Jun in HTLV-1 LTR activation by 12-O-tetradecanoylphorbol-13-acetate in different human T-cell lines

We have previously shown that TPA activates HTLV-1 LTR in Jurkat T-cells by inducing the binding of Sp1-p53 complex to the Sp1 site residing within the Ets responsive region 1 (ERR-1) of the LTR and that this activation is inhibited by PKCalpha and PKCepsilon. However, in H9 T-cells TPA has been noted to activate the LTR in two consecutive stages. The first stage is activation is mediated by PKCetta and requires the three 21 bp TRE repeats. The second activation mode resembles that of Jurkat cells, except that it is inhibited by PKCdelta. The present study revealed that the first LTR activation in H9 cells resulted from PKCetta-induced elevation of non-phosphorylated c-Jun which bound to the AP-1 site residing within each TRE. In contrast, this TRE-dependent activation did not occur in Jurkat cells, since there was no elevation of non-phosphorylated c-Jun in these cells. However, we found that PKCalpha and PKCepsilon, in Jurkat cells, and PKCetta and PKCdelta, in H9 cells, increased the level of phosphorylated c-Jun that interacted with the Sp1-p53 complex. This interaction prevented the Sp1-p53 binding to ERR-1 and blocked, thereby, the ERR-1-mediated LTR activation. Therefore, this PKC-inhibited LTR activation started in both cell types after depletion of the relevant PKCs by their downregulation. In view of these variable activating mechanisms we assume that there might be additional undiscovered yet modes of HTLV-1 LTR activation which vary in different cell types. Moreover, in line with this presumption we speculate that in HTLV-1 carriers the LTR of the latent provirus may also be reactivated by different mechanisms that vary between its different host T-lymphocyte subclones. Since this reactivation may initiate the ATL process, understanding of these mechanisms is essential for establishing strategies to block the possibility of reactivating the latent virus as preventive means for ATL development in carriers.

Targeting Bcl-2 family proteins in adult T-cell leukemia/lymphoma: in vitro and in vivo effects of the novel Bcl-2 family inhibitor ABT-737

Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell malignancy caused by human T-lymphotropic virus type I (HTLV-1). ABT-737, a small molecule inhibitor of Bcl-2, Bcl-X(L), and Bcl-w, significantly induced apoptosis in HTLV-1 infected T-cell lines as well as in fresh ATLL cells, and synergistically enhanced the cytotoxicity and apoptosis induced by conventional cytotoxic drugs. Moreover, ABT-737 significantly inhibited the in vivo tumor growth of an ATLL mouse model. These results suggest that the use of an agent targeting anti-apoptotic bcl-2 family proteins, either alone or in combination with other conventional drugs, represents a novel promising approach for ATLL.

An update on the management of peripheral T-cell lymphoma and emerging treatment options

Peripheral T-cell lymphomas (PTCLs) comprise a rare and heterogeneous subset of non-Hodgkin’s lymphomas (NHLs) that arise from post-thymic T-cells or natural killer (NK)-cells at nodal or extranodal sites. Worldwide, PTCLs represent approximately 12% of all NHLs and the 2008 World Health Organization (WHO) classification includes over 20 biologically and clinically distinct T/NK-cell neoplasms that differ significantly in presentation, pathology, and response to therapy. Because of the rarity and heterogeneity of these diseases, large clinical trials have not been conducted and optimal therapy is not well defined. Most subtypes are treated with similar combination chemotherapy regimens as used for aggressive B-cell NHL, but with poorer outcomes. New treatment combinations and novel agents are currently being explored for PTCLs and this review highlights a number of options that appear promising.

Molecular determinants of human T-lymphotropic virus type 1 transmission and spread

Human T-lymphotrophic virus type-1 (HTLV-1) infects approximately 15 to 20 million people worldwide, with endemic areas in Japan, the Caribbean, and Africa. The virus is spread through contact with bodily fluids containing infected cells, most often from mother to child through breast milk or via blood transfusion. After prolonged latency periods, approximately 3 to 5% of HTLV-1 infected individuals will develop either adult T-cell leukemia/lymphoma (ATL), or other lymphocyte-mediated disorders such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The genome of this complex retrovirus contains typical gag, pol, and env genes, but also unique nonstructural proteins encoded from the pX region. These nonstructural genes encode the Tax and Rex regulatory proteins, as well as novel proteins essential for viral spread in vivo such as, p30, p12, p13 and the antisense encoded HBZ. While progress has been made in the understanding of viral determinants of cell transformation and host immune responses, host and viral determinants of HTLV-1 transmission and spread during the early phases of infection are unclear. Improvements in the molecular tools to test these viral determinants in cellular and animal models have provided new insights into the early events of HTLV-1 infection. This review will focus on studies that test HTLV-1 determinants in context to full length infectious clones of the virus providing insights into the mechanisms of transmission and spread of HTLV-1.

Clonal structure of rapid-onset MDV-driven CD4+ lymphomas and responding CD8+ T cells

Lymphoid oncogenesis is a life threatening complication associated with a number of persistent viral infections (e.g. EBV and HTLV-1 in humans). With many of these infections it is difficult to study their natural history and the dynamics of tumor formation. Marek's Disease Virus (MDV) is a prevalent α-herpesvirus of poultry, inducing CD4+ TCRαβ+ T cell tumors in susceptible hosts. The high penetrance and temporal predictability of tumor induction raises issues related to the clonal structure of these lymphomas. Similarly, the clonality of responding CD8 T cells that infiltrate the tumor sites is unknown. Using TCRβ repertoire analysis tools, we demonstrated that MDV driven CD4+ T cell tumors were dominated by one to three large clones within an oligoclonal framework of smaller clones of CD4+ T cells. Individual birds had multiple tumor sites, some the result of metastasis (i.e. shared dominant clones) and others derived from distinct clones of transformed cells. The smaller oligoclonal CD4+ cells may represent an anti-tumor response, although on one occasion a low frequency clone was transformed and expanded after culture. Metastatic tumor clones were detected in the blood early during infection and dominated the circulating T cell repertoire, leading to MDV associated immune suppression. We also demonstrated that the tumor-infiltrating CD8+ T cell response was dominated by large oligoclonal expansions containing both “public” and “private” CDR3 sequences. The frequency of CD8+ T cell CDR3 sequences suggests initial stimulation during the early phases of infection. Collectively, our results indicate that MDV driven tumors are dominated by a highly restricted number of CD4+ clones. Moreover, the responding CD8+ T cell infiltrate is oligoclonal indicating recognition of a limited number of MDV antigens. These studies improve our understanding of the biology of MDV, an important poultry pathogen and a natural infection model of virus-induced tumor formation.

Many viral infections target the immune system, making use of the long lived, highly proliferative lymphocytes to propagate and survive within the host. This characteristic has led to an association between some viruses such as Epstein Barr Virus (EBV), Human T cell Lymphotrophic Virus-1 (HTLV-1) and Mareks Disease Virus (MDV) and lymphoid tumors. We employed methods for identifying the T cell receptor repertoire as a molecular bar-code to study the biology of MDV-induced tumors and the anti-tumor response. Each individual contained a small number of large (high frequency) tumor clones alongside some smaller (lower frequency) clones in the CD4+ T cell population. The tumor infiltrating CD8+ T cell response was highly focused with a small number of large clones, with one representing a public CDR3 sequence. This data is consistent with the recognition of a small number of dominant antigens and understanding the relationship between these and protective immunity is important to improve development of new vaccination strategies. Collectively, our results provide insights into the clonal structure of MDV driven tumors and in the responding CD8+ T cell compartment. These studies advance our understanding of MDV biology, an important poultry disease and a natural infection model of virus-induced tumor formation.

A comparative study of HIV-1 and HTLV-I protease structure and dynamics reveals a conserved residue interaction network

The two retroviruses human T-lymphotropic virus type I (HTLV-I) and human immunodeficiency virus type 1 (HIV-1) are the causative agents of severe and fatal diseases including adult T-cell leukemia and the acquired immune deficiency syndrome (AIDS). Both viruses code for a protease that is essential for replication and therefore represents a key target for drugs interfering with viral infection. The retroviral proteases from HIV-1 and HTLV-I share 31% sequence identity and high structural similarities. Yet, their substrate specificities and inhibition profiles differ substantially. In this study, we performed all-atom molecular dynamics (MD) simulations for both enzymes in their ligand-free states and in complex with model substrates in order to compare their dynamic behaviors and enhance our understanding of the correlation between sequence, structure, and dynamics in this protein family. We found extensive similarities in both local and overall protein dynamics, as well as in the energetics of their interactions with model substrates. Interestingly, those residues that are important for strong ligand binding are frequently not conserved in sequence, thereby offering an explanation for the differences in binding specificity. Moreover, we identified an interaction network of contacts between conserved residues that interconnects secondary structure elements and serves as a scaffold for the protein fold. This interaction network is conformationally stable over time and may provide an explanation for the highly similar dynamic behavior of the two retroviral proteases, even in the light of their rather low overall sequence identity.

Silencing of HTLV-1 gag and env genes by small interfering RNAs in HEK 293 cells

Since the discovery of RNAi technology, several functional genomic and disease therapy studies have been conducted using this technique in the field of oncology and virology. RNAi-based antiviral therapies are being studied for the treatment of retroviruses such as HIV-1. These studies include the silencing of regulatory, infectivity and structural genes. The HTLV-1 structural genes are responsible for the synthesis of proteins involved in the entry, assembly and release of particles during viral infection. To examine the possibility of silencing HTLV-1 genes gag and env by RNA interference technology, these genes were cloned into reporter plasmids. These vectors expressed the target mRNAs fused to EGFP reporter genes. Three small interference RNAs (siRNAs) corresponding to gag and three corresponding to env were designed to analyze the effect of silencing by RNAi technology. The plasmids and siRNAs were co-transfected into HEK 293 cells. The results demonstrated that the expression of the HTLV-1 gag and env genes decreased significantly in vitro. Thus, siRNAs can be used to inhibit HTLV-1 structural genes in transformed cells, which could provide a tool for clarifying the roles of HTLV-1 structural genes, as well as a therapy for this infection.

Schedule-dependent inhibition of T-cell lymphoma cells by cotreatment with the mTOR inhibitor everolimus and anticancer drugs

OBJECTIVE

Everolimus (RAD001) is a novel mammalian target of rapamycin (mTOR) inhibitor, and anti-proliferative activity in various malignancies has been reported. This study evaluated the anti-tumor effects and schedule-dependent synergism of everolimus in combination with other chemotherapeutic agents in T-cell lymphoma cell lines.

MATERIALS AND METHODS

Human T-cell lymphoma cell lines Hut-78 and Jurkat were treated with increasing doses of everolimus, alone or in combination with doxorubicin, etoposide, vincristine, or bortezomib, using different dosing schedules. Anti-tumor effects were measured by assays for cell proliferation, apoptosis, and cell cycle distribution. Drug interactions were determined by median effect analysis.

RESULTS

Exposure to everolimus alone induced G1 phase cell cycle arrest without significant apoptosis. With certain dosing schedules, everolimus showed synergism with doxorubicin, etoposide, and bortezomib, but antagonism with vincristine. Cytotoxic synergism was observed following cotreatment with doxorubicin and everolimus, bortezomib and everolimus, doxorubicin followed by everolimus, and bortezomib followed by everolimus. By contrast, cell exposure to everolimus followed by doxorubicin or followed by bortezomib resulted in antagonistic effects. Sequential exposure to doxorubicin or bortezomib followed by everolimus effectively prevented potential negative interactions, and resulted in drug synergism. Drug combination synergisms or antagonisms were associated with variable effects on the cell cycle distribution.

CONCLUSIONS

Everolimus effectively inhibited the growth of T-cell lymphoma cells in vitro. Specific schedule-dependent combinations of everolimus with other anti-tumor agents which avoid potential drug antagonism and produce effective synergism may lead to clinically effective treatments for T-cell lymphoma.

Mouse models of human T lymphotropic virus type-1-associated adult T-cell leukemia/lymphoma

Human T-lymphotropic virus type-1 (HTLV-1), the first human retrovirus discovered, is the causative agent of adult T-cell leukemia/lymphoma (ATL) and a number of lymphocyte-mediated inflammatory conditions including HTLV-1-associated myelopathy/tropical spastic paraparesis. Development of animal models to study the pathogenesis of HTLV-1-associated diseases has been problematic. Mechanisms of early infection and cell-to-cell transmission can be studied in rabbits and nonhuman primates, but lesion development and reagents are limited in these species. The mouse provides a cost-effective, highly reproducible model in which to study factors related to lymphoma development and the preclinical efficacy of potential therapies against ATL. The ability to manipulate transgenic mice has provided important insight into viral genes responsible for lymphocyte transformation. Expansion of various strains of immunodeficient mice has accelerated the testing of drugs and targeted therapy against ATL. This review compares various mouse models to illustrate recent advances in the understanding of HTLV-1-associated ATL development and how improvements in these models are critical to the future development of targeted therapies against this aggressive T-cell lymphoma.

Adult T-Cell Leukemia/Lymphoma with CLL-Like Morphology-A Case Report

Adult T-cell Leukemia/Lymphoma (ATL) is rarely seen in the U.S. and Europe, usually limited to African Americans from the southeastern U.S. and immigrants from HTLV-1 endemic areas. Reaching an accurate and timely diagnosis of ATL in such nonendemic areas can be challenging, owing to limited exposure, diverse manifestations, and varying cell morphology. We present a case of chronic adult T-cell leukemia (ATL) with Chronic Lymphocytic Leukemia- (CLL-) like morphology that remained untreated for ten years and then developed treatment refractory acute ATL crisis.

Rapidly fatal HTLV-1-associated T-cell leukemia/lymphoma in a patient with SLE

BACKGROUND

A 57-year-old Afro-Jamaican woman with an 8-year history of systemic lupus erythematosus, including lupus nephritis, was admitted to hospital with intractable back pain accompanied by fever and severe malaise. At the time of presentation she was receiving immunosuppressive treatment with glucocorticoids and azathioprine. She also had gout, hypertension and type II diabetes.

INVESTIGATIONS

Physical and neurological examination and laboratory analyses, including biochemical, hematological and electrophoresis tests, X-ray of the lumbar spine, pelvis and chest, mammography, MRI of the lumbar spine, thoracic and abdominal CT, and biopsy of a peripheral lymph node and bone marrow with immunohistochemistry and serology for human T-cell lymphotrophic virus (HTLV) 1 and 2.

DIAGNOSIS

HTLV-1-associated acute adult T-cell leukemia/lymphoma with bone marrow infiltration and hypercalcemia. Reaching the correct diagnosis was difficult and only possible through close collaboration with the pathologist and with consideration of the patient's ethnic and geographical background.

MANAGEMENT

Chemotherapy with high-dose prednisone and adjusted doses of cyclophosphamide and doxorubicin. The patient developed tumor lysis syndrome and died 3 weeks after the diagnosis was made.