Progression Of Adult T-cell Leukemia/lymphoma Research Articles

Single-Cell RNA Sequencing Revealed the YY1/EZH2/MLH1 Axis As a Possible Therapeutic Target of Intractable Adult T-Cell Leukemia

Background: Due to clinical heterogeneity of adult T-cell leukemia/lymphoma (ATL) and its diverse genetic abnormality, common therapeutic targets of ATL remains unclear. Whereas the YY1/EZH2 axis regulates global epigenetic modification of genes in ATL, its downstream target genes have not been fully elucidated. Meanwhile, DNA mismatch repair proteins may be targeted in ATL. Here we explored underlying molecular axes for ATL progression through comprehensive single-cell RNA-sequencing (sc-RNA-seq). Methods: Peripheral blood of 42 ATL patients and asymptomatic HTLV-1 carriers in addition to two cell lines of ATL43T and ED+ were subjected to the following analyses. Molecular markers associated with their clinical phenotypes were extracted through sc-RNA-seq analysis. Expression levels of DNA mismatch repair proteins (MLH1, MSH2) and target molecules were validated by flow cytometry. Finally, their function was verified through lentiviral shRNA-dependent knockdown and molecular-targeting reagents. Results: While the frequencies of CADM1+ cells among CD4+ T cells were generally correlated with HTLV-1 proviral loads (R = 0.76, p < 0.001), substantial CADM1+ cells were detected but did not increase in some long-remitted cases; thus, CADM1+ cells are biologically heterogeneous. sc-RNA-seq of CADM1+ cells of four ATL cases identified a cluster of CD48-deficient cells. in silico promoter analysis of the cluster extracted a transcription factor YY1 as a candidate for common master regulators. EZH2 and the putative driver genes (CELF2, PTPRC, CBLB, ATXN1, IKZF2) were identified as differentially expressed genes (DEGs) in the cluster. The EZH2-overexpressed cluster was increased in acute-type ATL compared with remitted ATL and smoldering-type ATL. Interestingly, the cluster increased moderately in the other smoldering-type ATL, which required UVB irradiation due to intractable skin lesion. Given that YY1 and EZH2 were up-regulated in acute-type ATL, the cluster may represent tumor aggressiveness. Furthermore, biphasic expression of YY1/EZH2 was observed in 2 acute-type ATL, which indicates that the EZH2 high ATL cells confer malignant signature. In-house analysis on microarray dataset GSE55851 specified the MLH1 associated with YY1/EZH2. MLH1 within CADM1+ fraction was down-regulated in ATL patients with remission (n = 7) but maintained in progressive ATL (n = 6) (p < 0.05). Lentiviral shYY1 knockdown resulted in down-regulation of MLH1 in both ATL43T and ED+ (p < 0.01). The EZH1/2 inhibitor valemetostat down-regulated EZH2 (p = 0.018) and MLH1 (p = 0.014) in primary ATL cells. Finally, knockdown of either YY1 or MLH1 suppressed proliferation of ATL43T and ED+ (p < 0.0001). Conclusions: Our findings indicate that down-regulation of MLH1 through YY1/EZH2 inhibition plays a key role in the treatment of aggressive ATL.

Decoding dysregulated angiogenesis in HTLV-1 asymptomatic carriers compared to healthy individuals.

Human T-cell lymphotropic virus type 1 (HTLV-1) is the first identified human retrovirus responsible for two significant diseases: HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia/lymphoma (ATLL). Although the majority of infected individuals remain asymptomatic carriers, a small percentage may develop ATLL or HAM/TSP. In tumorigenesis, a crucial process is angiogenesis, which involves the formation of new blood vessels. However, the precise mechanism of HTLV-1 associated angiogenesis remains unclear. This study aims to investigate the gene regulation involved in the angiogenesis signaling pathway associated with HTLV-1 infection. The research enrolled 20 male participants, including asymptomatic carriers and healthy individuals. Blood samples were collected and screened using ELISA for HTLV-1 confirmation, and PCR was performed for both Tax and HBZ for validation. RNA extraction and cDNA synthesis were carried out, followed by RT-qPCR analysis targeting cellular genes involved in angiogenesis. Our findings indicate that gene expression related to angiogenesis was elevated in HTLV-1 ACs patients. However, the differences in gene expression of the analyzed genes, including HSP27, Paxillin, PDK1, PTEN, RAF1, SOS1, and VEGFR2 between ACs and healthy individuals were not statistically significant. This suggests that although angiogenesis-related genes may show increased expression in HTLV-1 infection, they might not be robust indicators of ATLL progression in asymptomatic carriers. The results of our study demonstrate that angiogenesis gene expression is altered in ACs of HTLV-1, indicating potential involvement of angiogenesis in the early stages before ATLL development. While we observed elevated angiogenesis gene expression in ACs, the lack of statistical significance between ACs and healthy individuals suggests that these gene markers may not be sufficient on their own to predict the development of ATLL in asymptomatic carriers.

The development of adult T cell leukemia/lymphoma in renal transplant recipients: report of two cases with literature review

BackgroundsTherefore, reports on the risk of HTLV-1-related diseases in organ transplantation have increased in recent years, and the management of HTLV in renal transplantation remains a challenge.Patients and methodsWe retrospectively analyzed four HTLV-1-positive recipients or donors among 89 renal transplantation cases from 2006 to 2021.ResultsAmong the four HTLV-1-positive recipients, two patients developed adult T cell leukemia/lymphoma (ATL) derived from recipients at approximately 3 years (1016 days and 1195 days) after renal transplantation. Case 1 developed lymphoma-type ATL (an extranodal primary cutaneous variant), including skin and pulmonary lesions. The patient achieved CR with FK tapering and CHOP therapy following cord blood stem cell transplantation. However, the patient died 101 days after ATL development because of a severe fungal infection. Case 2 developed acute-type ATL with an unusual phenotype of CD4+8+30+. The patient was treated with FK tapering and palliative therapy because of poor PS. Notably, in case 1, histopathological findings showed high numbers of PD-1-positive TIL cells in ATL, suggesting exhausted T cells and a correlation with the early onset of ATL. Furthermore, in Case 2, histopathological findings revealed CD 30 expression in ATL cells, suggesting the importance of CD 30 in ATL development. Importantly, case 2 showed typical driver mutations, including CCR4 truncation mutations of the C-terminal, TBL1XR1 mutation, and TP53 mutation in the splice site. Notably, our present study and our previous study on renal transplantation strongly indicated that two out of two and one out of 59 “recipient” positive cases developed ATL, respectively. Furthermore, our previous nationwide study 4 out of 10 “donor” positive cases developed HAM. These findings showed that ATL may be derived from HTLV-I+ recipient cells and HAM may be derived from HTLV-1+ donor cells, although the precise mechanism remains unknown.ConclusionsThus, early onset and rapid progression of ATL with poor outcomes should be considered in HTLV-1 endemic areas. Furthermore, immunological or genetic mechanisms may be related to the development of ATL after renal transplantation. We believe that the mechanism of onset of ATL after transplantation may be important when considering the immune environment of ATL itself.

CD30 Expression and Its Functions during the Disease Progression of Adult T-Cell Leukemia/Lymphoma.

CD30, a member of the tumor necrosis factor receptor superfamily, plays roles in pro-survival signal induction and cell proliferation in peripheral T-cell lymphoma (PTCL) and adult T-cell leukemia/lymphoma (ATL). Previous studies have identified the functional roles of CD30 in CD30-expressing malignant lymphomas, not only PTCL and ATL, but also Hodgkin lymphoma (HL), anaplastic large cell lymphoma (ALCL), and a portion of diffuse large B-cell lymphoma (DLBCL). CD30 expression is often observed in virus-infected cells such as human T-cell leukemia virus type 1 (HTLV-1). HTLV-1 is capable of immortalizing lymphocytes and producing malignancy. Some ATL cases caused by HTLV-1 infection overexpress CD30. However, the molecular mechanism-based relationship between CD30 expression and HTLV-1 infection or ATL progression is unclear. Recent findings have revealed super-enhancer-mediated overexpression at the CD30 locus, CD30 signaling via trogocytosis, and CD30 signaling-induced lymphomagenesis in vivo. Successful anti-CD30 antibody-drug conjugate (ADC) therapy for HL, ALCL, and PTCL supports the biological significance of CD30 in these lymphomas. In this review, we discuss the roles of CD30 overexpression and its functions during ATL progression.

The oncogenic driving force of CD30 signaling-induced chromosomal instability in adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) develops via stepwise accumulation of gene mutations and chromosome aberrations. However, the molecular mechanisms underlying this tumorigenic process are poorly understood. We previously reported the presence of a biological link between the expression of CD30, which serves as a marker for ATL progression, and the actively proliferating fraction of human T-cell leukemia virus type 1 (HTLV-1)-infected cells that display polylobulation. Here, we demonstrated that CD30 signaling induced chromosomal instability with clonal expansion through DNA double-strand breaks (DSBs) via an increase of intracellular reactive oxygen species. CD30+ ATL cells were composed of subclones with additional genomic aberrations compared with CD30- ATL cells in ATL patients. Furthermore, we found an accumulation of copy number loss of DSB repair-related genes as the disease progressed. Taken together, CD30 expression on ATL cells appears to be correlated with genomic instability, suggesting that CD30 signaling is one of the oncogenic factors of ATL progression with clonal evolution. This study provides new insight into the biological roles of CD30 signaling and could improve our understanding of tumorigenic processes of HTLV-1-infected cells.

Highly Sensitive Detection Method Reveals Significant Anti-Tumor Activity of Valemetostat in Patients with Relapsed/Refractory Adult T Cell Leukemia

Background: Enhancer of zeste homolog 2 (EZH2) and its close homolog, EZH1, catalyze the attachment of 3 methyl groups to histone H3 at lysine 27 (H3K27me3). H3K27me3 is an epigenetic mark involved in downregulating gene expression associated with tumor suppression and cell differentiation. Adult T-cell leukemia/lymphoma (ATL) is an aggressive non-Hodgkin lymphoma (NHL) subtype that arises from CD4 positive T cells associated with human T-lymphotropic virus type 1 (HTLV-1) infection. During asymptomatic period, genetic and epigenetic abnormalities in the HTLV-1 infected cells accumulates and finally leads to ATL development. Current therapy for aggressive type ATL is still unsatisfactory and prognosis of relapsed and refractory (r/r) ATL after lenalidomide or mogamulizumab treatment is poor. Dysregulation of EZH2/PRC2-mediated epigenome status has been reported to be highly involved in tumorigenesis in ATL as well as other tumors such as B cell lymphoma. Valemetostat is a potent dual inhibitor of EZH1 and 2 which are key catalytic subunits of PRC2. The safety and efficacy of valemetostat in patients with r/r ATL were evaluated in a multicenter, single-arm, open-label phase 2 study (NCT04102150) and the results were presented at ASH 2021. Here we show clinical biomarker data using peripheral blood obtained over time, accompanying clinical outcomes. Also we discuss relevance of the measured data in blood to clinical outcomes among assay formats. Method: In the Ph2 study, valemetostat 200mg was orally administrated once daily in continuous 28-day cycles until disease progression or intolerance. Nine of 25 patients in the Ph2 study had abnormal lymphocytes in their peripheral blood. Peripheral blood from these 9 patients (7 acute and 2 unfavorable chronic) was drawn at pre-dosing and every 4-weeks for the analysis of this study. Abnormal lymphocytes (Ably) and soluble IL-2R (sIL-2R) are indicator of ATL prognosis. For HTLV-1 proviral load (PVL) detection, genomic DNA was extracted from PBMC from each patient. Droplet Digital PCR (ddPCR) was performed using probes specific for HTLV-1 provirus and RNase 5’ pyrophospgohydrolase (RPPH) gene. % PVL was determined from the copy number ratio of HTLV-1 to RPPH1 genes. For HTLV-1 Analysis System (HAS)-flow cytometry, frozen cell suspensions were thawed and stained with anti- CD3/4/7/14/CADM1 Abs. The data from live T cells was analyzed by CD7 versus CADM1 plot. CADM1+CD7- population ratio was denoted as %N. We analyzed changes of each measured parameter in every patient in comparison with clinical outcome. Result: In the 9 patients who met criteria in blood collection for blood biomarker evaluation at screening, 1 CR, 6 PRs and 1 SD were observed as the best response by blood assessment (not evaluable in one patient, who failed to meet criteria for blood assessment at pre-treatment evaluation). Significant decrease in Ably number and blood sIL-2R concentration was observed after 4-week valemetostat treatment in all 9 patients and this decrease was maintained during the treatment until PD. Valemetostat also decreased the %PVL and %N in HAS-flow. The reduction trends were weaker in comparison with Ably and sIL-2R. As for %PVL, most of the patients experienced modest reduction and sustained around 50%. Especially HAS-flow results exhibited two patient groups with either lower (<25%) or higher %N at pre-dosing. Two patients in the lower %N group showed CR or PR, and in overall response the remaining 7 patients with higher %N showed SD or PR. Conclusion: Valemetostat significantly reduced markers of ATL progression. Ably and sIL-2R to very low levels in all patients. In contrast, PVL assay did not exhibit complete %PVL reduction. HAS-flow showed variable %N at pre-dosing and the patients with higher %N exhibited SD or PR throughout the treatment in overall response and blood assessment. These data suggest that PVL assay and HAS-flow can detect ATL cells with a high resolution, which cannot be detected by Ably and sIL-2R, when valemetostat has significant therapeutic efficacy in ATL patients. Further analyses, such as gene mutation, transcription, chromatin state and histone methylation, using the collected blood samples will be performed next.

Signaling factors potentially associated to the pathogenesis of Adult T-cell leukemia /lymphoma: A network-analysis and novel findings assessment

Adult T-cell leukemia/lymphoma (ATLL) is a human T-cell leukemia virus (HTLV) type 1-associated disease of TCD4+ cell transformation. Despite extensive studies on ATLL development and progression, the fundamental processes of HTLV-1 oncogenicity are yet to be understood. This study aimed to integrate high-throughput microarray datasets to find novel genes involved in the mechanism of ATLL progression. For this purpose, five microarray datasets were downloaded from the Gene Expression Omnibus database and then profoundly analyzed. Differentially expressed genes and miRNAs were determined using the MetaDE package in the R software and the GEO2R web tool. The STRING database was utilized to construct the protein-protein interaction network and explore hub genes. Gene ontology and pathway enrichment analysis were carried out by employing the EnrichR web tool. Furthermore, flow cytometry was employed to assess the CD4/CD8 ratio, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to confirm the high-throughput data analysis results. Four miRNAs, including hsa-mir-146, hsa-mir-451, hsa-mir-31, and hsa-mir-125, were among the statistically significant differentially expressed miRNAs between healthy individuals and ATLL patients. Moreover, 924 differentially expressed genes were identified between normal and ATLL samples. Further network analysis highlighted 59 hub genes mainly regulating pathways implicated in viral interferences, immunological processes, cancer, and apoptosis pathways. Among the identified hub genes, RhoA and PRKACB were most considerable in the high-throughput analysis and were further validated by qRT-PCR. The RhoA and PRKACB expression were significantly down-regulated in ATLL patients compared to asymptomatic carriers (p<0.0001 and p=0.004) and healthy subjects (p=0.043 and p=0.002). Therefore, these corresponding miRNAs and proteins could be targeted for diagnosis purposes and designing effective treatments.

Oncogenic isoform switch of tumor suppressor BCL11B in adult T-cell leukemia/lymphoma

B-Cell leukemia/lymphoma 11B (BCL11B) is a transcription factor important for T-cell development and acts as a tumor suppressor gene in T-cell acute lymphoblastic leukemia. Here, we identified BCL11B as a candidate leukemia-associated gene in human T-cell leukemia virus type 1 (HTLV-1)-induced adult T-cell leukemia/lymphoma (ATLL). Interestingly, the short form lacking exon 3 (BCL11B/S) protein was more highly expressed than the full-length BCL11B (BCL11B/L) in leukemic cells from most of the ATLL patients, although expression ratios of BCL11B/L to BCL11B/S were almost equal in control CD4+ T cells. BCL11B/S and BCL11B/L exhibited distinct subcellular localization and differential effects on cellular growth; BCL11B/L expression exhibited nuclear localization and inhibited cell growth in ATLL cells, whereas BCL11B/S exhibited nucleocytoplasmic distribution and accelerated cell growth. Furthermore, BCL11B/S expression accelerated the development of T-cell leukemia/lymphomas in transgenic mice carrying HTLV-1/HBZ, a critical viral factor in leukemogenesis, whereas these phenotypes did not occur in the double transgenic mice carrying BCL11B/L and HTLV-1/HBZ. In HTLV-1-infected T-cell lines, BCL11B expression is downregulated by HTLV-1/Tax, a viral factor necessary at the early stage of leukemogenesis. These results suggest that downregulation of BCL11B/L expression and upregulation of BCL11B/S may contribute to the development and progression of ATLL.

Integration of gene co-expression analysis and multi-class SVM specifies the functional players involved in determining the fate of HTLV-1 infection toward the development of cancer (ATLL) or neurological disorder (HAM/TSP).

Human T-cell Leukemia Virus type-1 (HTLV-1) is an oncovirus that may cause two main life-threatening diseases including a cancer type named Adult T-cell Leukemia/Lymphoma (ATLL) and a neurological and immune disturbance known as HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). However, a large number of the infected subjects remain as asymptomatic carriers (ACs). There is no comprehensive study that determines which dysregulated genes differentiate the pathogenesis routes toward ATLL or HAM/TSP. Therefore, two main algorithms including weighted gene co-expression analysis (WGCNA) and multi-class support vector machines (SVM) were utilized to find major gene players in each condition. WGCNA was used to find the highly co-regulated genes and multi-class SVM was employed to identify the most important classifier genes. The identified modules from WGCNA were validated in the external datasets. Furthermore, to find specific modules for ATLL and HAM/TSP, the non-preserved modules in another condition were found. In the next step, a model was constructed by multi-class SVM. The results revealed 467, 3249, and 716 classifiers for ACs, ATLL, and HAM/TSP, respectively. Eventually, the common genes between the WGCNA results and classifier genes resulted from multi-class SVM that also determined as differentially expressed genes, were identified. Through these step-wise analyses, PAIP1, BCAS2, COPS2, CTNNB1, FASLG, GTPBP1, HNRNPA1, RBBP6, TOP1, SLC9A1, JMY, PABPC3, and PBX1 were found as the possible critical genes involved in the progression of ATLL. Moreover, FBXO9, ZNF526, ERCC8, WDR5, and XRCC3 were identified as the conceivable major involved genes in the development of HAM/TSP. These genes can be proposed as specific biomarker candidates and therapeutic targets for each disease.

TAS‐116 (pimitespib), a heat shock protein 90 inhibitor, shows efficacy in preclinical models of adult T‐cell leukemia

Adult T‐cell leukemia/lymphoma (ATL) is a highly chemoresistant malignancy of peripheral T lymphocytes caused by human T‐cell leukemia virus type 1 infection, for which there is an urgent need for more effective therapeutic options. The molecular chaperone heat shock protein 90 (HSP90) plays a crucial role in nuclear factor‐κB (NF‐κB)‐mediated antiapoptosis in ATL cells, and HSP90 inhibitors are new candidate therapeutics for ATL. Accordingly, we investigated the anti‐ATL effects of a novel oral HSP90 inhibitor, TAS‐116 (pimitespib), and the mechanisms involved in ex vivo and in vivo preclinical models. TAS‐116 achieved IC50 values of less than 0.5 μmol/L in 10 ATL‐related cell lines and less than 1 μmol/L in primary peripheral blood cells of nine ATL patients; no toxicity was observed toward CD4+ lymphocytes from healthy donors, indicating the safety of this agent. Given orally, TAS‐116 also showed significant inhibitory effects against tumor cell growth in ATL cell‐xenografted mice. Furthermore, gene expression profiling of TAS‐116‐treated Tax‐positive or ‐negative cell lines and primary ATL cells using DNA microarray and multiple pathway analysis revealed the significant downregulation of the NF‐κB pathway in Tax‐positive cells and cell‐cycle arrest in Tax‐negative cells and primary ATL cells. TAS‐116 suppressed the activator protein‐1 and tumor necrosis factor pathways in all examined cells. These findings strongly indicate the efficacy of TAS‐116, regardless of the stage of ATL progression, and its potential application as a novel clinical anti‐ATL therapeutic agent.

Pivotal Phase 2 Study of the EZH1 and EZH2 Inhibitor Valemetostat Tosylate (DS-3201b) in Patients with Relapsed or Refractory Adult T-Cell Leukemia/Lymphoma

Pivotal Phase 2 Study of the EZH1 and EZH2 Inhibitor Valemetostat Tosylate (DS-3201b) in Patients with Relapsed or Refractory Adult T-Cell Leukemia/Lymphoma

Dissecting Multicellular Ecosystems of HTLV-1 Infection and ATL By Multi-Omics Single Cell Analysis

Adult T-cell leukemia/lymphoma (ATL) is an aggressive peripheral T-cell malignancy, caused by human T-cell leukemia virus type-1 (HTLV-1) infection. To elucidate immune microenvironment and heterogeneity of HTLV-1-infected normal and leukemic cells, we performed multi-omics single cell analysis, evaluating whole-transcriptome, 101 surface marker proteins, and T/B-cell receptor repertoires in the same single cells. We analyzed 236,192 peripheral blood mononuclear cells (PBMCs) from 31 ATL patients (35 samples including 4 sequential samples), 11 HTLV-1-infected carriers, and 4 healthy donors. In our analysis, expression of HTLV-1-related genes, such as HBZ, clearly identified a distinct cluster of HTLV-1-infected cells within non-malignant CD4+ T cells. These cells are characterized by a CD45RO+CD62L-CD7-CCR4+CD25+CD73+ memory/effector phenotype. By contrast, malignant ATL cells were segregated into different clusters across patients, suggestive of inter-tumor heterogeneity. Transcriptome analysis of CD4+ T cells revealed up-regulation of interferon (IFN) responses and down-regulation of TNFa signaling in malignant ATL cells compared with HTLV-1-infected normal CD4+ T cells. Likewise, sequential sample analysis showed that progression from indolent to aggressive disease enhanced IFN responses, suggesting a pivotal role of this pathway in the ATL pathogenesis. Surface marker protein analysis demonstrated that HTLV-1 infection up-regulated the expression of stimulatory and inhibitory immune checkpoint molecules (such as OX40 and TIGIT, respectively), which was further augmented by ATL progression. Within malignant cells, we identified a fraction of cycling cells present across most ATL samples. This fraction showed an enhanced T-cell activation markers, such as CD25 and HLA-DR, and their frequency was increased in aggressive subtypes. On the other hand, in HTLV-1-infected carriers, HTLV-1-infected CD4+ T cells contained a small population of malignant-like cells showing clonal expansion. The degree of clonal expansion was significantly correlated with HTLV-1 viral load in PBMCs. These results clarify the heterogeneity within HTLV-1-infected cells and ATL malignant cells, pointing to its relevance during ATL initiation and progression. We also observed dynamic changes of the immune microenvironment in ATL. Although the relative frequencies of other cell types remained almost the same or reduced, only myeloid cells were increased in ATL patients compared with in HTLV-1-infected carriers. Re-clustering of myeloid cells identified a novel cluster of monocytes expressing FCGR1A, encoding CD64, a biomarker of IFN-stimulated gene levels. Transcriptome analysis revealed increased IFN signaling and decreased TNFa in myeloid cells from ATL patients compared with HTLV-1-infected carriers. Similar expression signatures changes were also observed in various immune cell types, such as B, CD8+ T, and NK cells, in ATL patients. In addition, substantial changes of surface marker proteins were also found in ATL patients. Particularly, T-cell activation markers, such as HLA-DR, and inhibitory immune checkpoint molecules, such as PD-1 and TIM-3, were up-regulated in CD8+ T cells from ATL patients. A co-culture experiment of ATL cell lines with PBMCs from healthy volunteers demonstrated that ATL cells induced immune-phenotypic changes of myeloid and CD8+ T cells, similar to those observed in ATL patient by our single-cell analysis, confirming the role of ATL cells in the modulation of the immune system. Taken together, the composition and function of immune microenvironment is dramatically altered in ATL patients, which may contribute to immunosuppression and disease progression in ATL. In summary, our multi-omics single-cell analysis comprehensively dissects the cellular and molecular architecture in HTLV-1-infected carriers and ATL patients. In particular, our approach clearly defines HTLV-1-infected cells by the expression of HTLV-1-related genes, leading to the detailed characterization of HTLV-1-infected cells and elucidation of their difference from ATL malignant cells. These findings will help to devise novel diagnostic and therapeutic strategies for HTLV-1-related disorders. Disclosures Kogure: Takeda Pharmaceutical Company Limited.: Honoraria. Shimoda:Japanese Society of Hematology: Research Funding; The Shinnihon Foundation of Advanced Medical Treatment Research: Research Funding; Bristol-Myers Squibb: Honoraria; Takeda Pharmaceutical Company: Honoraria; Novartis: Honoraria, Research Funding; CHUGAI PHARMACEUTICAL CO., LTD.: Research Funding; Kyowa Hakko Kirin Co., Ltd.: Research Funding; Pfizer Inc.: Research Funding; Otsuka Pharmaceutical: Research Funding; Asahi Kasei Medical: Research Funding; Shire plc: Honoraria; Celgene: Honoraria; Perseus Proteomics: Research Funding; PharmaEssentia Japan: Research Funding; AbbVie Inc.: Research Funding; Astellas Pharma: Research Funding; Merck &amp; Co.: Research Funding. Kataoka:CHUGAI PHARMACEUTICAL CO., LTD.: Research Funding; Takeda Pharmaceutical Company: Research Funding; Otsuka Pharmaceutical: Research Funding; Asahi Genomics: Current equity holder in private company.

Whole-Genome Analysis of Adult T-Cell Leukemia/Lymphoma

Whole-Genome Analysis of Adult T-Cell Leukemia/Lymphoma

TACC3 expression as a prognostic factor in aggressive types of adult T-cell leukemia/lymphoma patients.

Adult T-cell leukemia/lymphoma (ATLL) is a malignant peripheral T-cell neoplasm associated with human T-cell leukemia virus type-1 (HTLV-1). The acute and lymphoma subtypes are regarded as aggressive ATLLs, and the overall survival (OS) of patients remains poor. Transforming acidic coiled-coil-containing protein 3 (TACC3) regulates microtubules, which are associated with cancer-related proteins overexpressed in various cancers. Such a relationship has not been reported in hematopoietic tumors, including ATLL. We examined tissue microarrays of histological samples from 92 cases of aggressive ATLL and assessed clinical features, including TACC3 protein expression levels. Compared with TACC3-low, TACC3-high ATLL patients were significantly older (P<.001), with a tendency toward pleomorphic variant over other morphological classifications (P=.019). TACC3-high patients (median survival time [MST] 10.6months, confidence interval [CI] [6.27-15.6]) had poorer OS compared to TACC3-low patients (MST 20months, CI [9.43-38.5]) (P=.0168). Moreover, multivariate analysis on TACC3 expression levels suggests that TACC3-high is an independent significant prognostic factor (HR, 1.700; 95% CI, 1.037-2.753; P=.0355). Certain drugs that inhibit TACC3-overexpressing neoplastic cells are used clinically. Further studies might highlight a key role for TACC3 in the oncogenesis and progression of ATLL.

PS1097 ADULT T‐CELL LEUKEMIA/LYMPHOMA: EPIDEMIOLOGY, CLINICAL FEATURES AND OUTCOME OF A CARIBBEAN COHORT FROM GUADELOUPE

Background:Adult T‐cell leukemia/lymphoma (ATLL) is a rare mature T‐cell malignancy first described in Japan in 1977. The causative agent of ATLL has been identified as the human T cell lymphotropic virus type 1 (HTLV‐1) which is endemic in Japan, Caribbean area, Central and South America and parts of sub‐Saharan Africa. Whereas Japanese cohorts of ATLL are commonly described, the studies gathering ATLL in the Caribbean islands are less frequently provided. ATLL is an unfrequent and subsequently unknown in Europa in opposite to the French overseas departments of the caribbean area.Aims:To report and describe ATLL in the lesser Antilles at the modern area of zidovudine and interferon treatment.Methods:We identified ATLL patients diagnosed in our institution between 2014 and 2018. Charts were reviewed to report clinicopathologic features, treatment patterns and outcomes of this Caribbean cohort exclusively diagnosed in Guadeloupe (French West Indies). ATLL diagnosis is based for all patients on the presence of a clonal T cells proliferation along with positivity for HTLV‐1 serology.Results:Among 309 patients positive for HTLV‐1 in this period, 24 developed an ATLL (7.76%). The median age at presentation is of 59 years (27–92). The sex ratio M/F was 11/13 (0.84). Based on the Shimoyama classification, 14 patients (58,9%) had acute subtype, 9 (37,5%) had lymphomatous and 1 (4,1%) chronic/smoldering disease. 22/24 had lymphadenopathy or deep tumoral syndrom at diagnosis whereas 2 patients presented splenomegaly. LDH was elevated in 23 patients (mean rate is 4.36N (0.94 – 28.03)). Hypercalcemia was present in half of the cases (mean value of 2,69 mg/dL (1.46 – 4.22)). Lymphocytosis was present in 7 patients (29%) and typical flower cells in 14 cases. Circulating lymphocyte phenotyping, performed for 19 patients, showed clonal T‐cells in 15 cases. Two third of the available karyotype were complex with abnormalities of the chromosome 14 in 50% of the cases.Most of the patients (n = 22, 91.6%) received first‐line treatment, whereas 8.3% (n = 2) quickly passed away before initiating any specific medication. As first line, 11 patients were treated by zidovudine and pegylated interferon +/‐ corticosteroid, 10 patients received a polychimiotherapy only or associated with zidovudine and peg‐interferon and one received corticosteroid only. Among the 15 patients with relapse or refractory diseases, 6 were able to receive a second line treatment. One patient benefits from haploidentical bone marrow transplantation. Five patients are still alive at last follow‐up : 3 patients in complete response (including the transplanted patient), 2 in partial response. Among them, 4 are still treated with interferon and zidovudine. Mean overall survival is 10.1 months (0.2–58.4). Among the 18 death with available data: 10 were related to ATLL progression, 6 related to infections and 2 patients died with acute respiratory distress syndrome.Summary/Conclusion:We report the first description of ATLL in Guadeloupe island. Compared to Japanese cohorts, we have younger patients and dominance of acute and lymphomatous ATLL subtypes. Cytologic detection of flower cells needs trained biologists and Shimoyama classification requires a very low blood cell count (&lt;1%) for lymphomatous category. Nevertheless, this detection can be improved by immunophenotyping which might be worthly introduced in this classification. Despite large and early use of zidovudine and interferon, with or without chemotherapy, ATLL remains a very poor prognostic disease confirming that innovative therapies are still needed.

Cells of adult T-cell leukemia evade HTLV-1 Tax/NF-κB hyperactivation–induced senescence

AbstractHuman T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma (ATL). The HTLV-1 viral trans-activator/oncoprotein Tax is a major driver of ATL, yet it induces rapid p21Cip1/Waf1 (p21)- and p27Kip1-mediated cellular senescence through constitutive activation (hyperactivation) of NF-κB. Although constitutive NF-κB activation is a common feature of T/B-cell leukemia/lymphoma, including ATL, it is not known how ATL cells maintain chronic NF-κB activation without undergoing senescence. Here, we demonstrate that, in contrast to HTLV-1− T-cell lines, ATL cell lines no longer undergo Tax-induced senescence. Although Tax+ and Tax− ATL cell lines showed signatures of constitutive NF-κB activation, their ability to progress through the cell cycle was unaffected. In some cases, ATL cell lines continued to proliferate despite significant upregulation of p21; additionally, many cell lines displayed altered expression of G1 and G1/S cyclins, particularly overexpression of cyclin D2. We propose that, during the course of ATL development, leukemia cells acquire genetic/epigenetic changes that can mitigate the senescence response triggered by NF-κB hyperactivation. Restoring the NF-κB–induced senescence response would likely help to control the development and progression of ATL and similar lymphoid malignancies.

Metabolic abnormalities in adult T-cell leukemia/lymphoma and induction of specific leukemic cell death using photodynamic therapy

Adult T-cell leukemia/lymphoma (ATL) is an aggressive T-cell neoplasm caused by human T-cell leukemia virus type I (HTLV-I). Therapeutic interventions have not been associated with satisfactory outcomes. We showed that the porphyrin metabolic pathway preferentially accumulates the endogenous photosensitive metabolite, protoporphyrin IX (PpIX) in ATL, after a short-term culture with 5-aminolevulinic acid (ALA). PpIX accumulated 10–100-fold more in ATL leukemic cells when compared to healthy peripheral blood mononuclear cells (PBMCs). Patient specimens showed dynamic changes in flow cytometry profiles during the onset and progression of ATL. Furthermore, 98.7% of ATL leukemic cell death in the ATL patient specimens could be induced with 10 min of visible light exposure, while 77.5% of normal PBMCs survived. Metabolomics analyses revealed that a specific stage of the metabolic pathway progressively deteriorated with HTLV-I infection and at the onset of ATL. Therefore, this method will be useful in diagnosing and identifying high-risk HTLV-I carriers with single cell resolutions. Photodynamic therapy in the circulatory system may be a potential treatment due to its highly-specific, non-invasive, safe, simultaneous, and repeatedly-treatable modalities.

Adult T cell leukemia aggressivenness correlates with loss of both 5-hydroxymethylcytosine and TET2 expression.

Mutations in TET2, encoding one of the TET members responsible for the conversion of DNA cytosine methylation to hydroxymethylation (5-hmc), have been recently described in Human T-lymphotropic virus type 1-associated adult T-cell leukemia/lymphoma (ATLL). However, neither the amount of genomic 5-hmc in ATLL tumor cells nor TET2 expression has been studied yet. In this study, we analyzed these two parameters as well as the mutational status of TET2 in ATLL patients. By employing a direct in situ approach, we documented that tumor T cells infiltrating lymph nodes exhibit low level of 5-hmc compared to residual normal T cells. Furthermore, this 5-hmc defect was more pronounced in tumor T cells from acute patients than from chronic ones and correlated with reduced expression of TET2 protein. TET2 variations were found in 14 patients (20%), including 13 with aggressive forms. Strikingly, 9 of the 14 patients showed the same variation (SNP rs72963007), whose frequency in ATLL patients was significantly higher than that of an ethnically matched control population (13% vs. 5%). However, no reduction of 5-hmc was found in PBMC from individuals possessing the variant rs72963007 TET2 allele, as compared to wild-type individuals. In contrast, a robust correlation was observed between 5-hmc and the levels of TET2 mRNA. Finally, loss of 5-hmc and TET2 downregulation both correlated with poor survival. These findings demonstrate that ATLL progression coincides with loss of genomic 5-hmc and indicate that downregulation of TET2, rather than TET2 mutations, is the key mechanism involved in 5-hmc modulation during ATLL progression.

Efficiency of AUY922 in mice with adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive malignancy caused by human T-cell leukemia virus type 1 (HTLV-1). ATLL is associated with poor prognosis mainly due to resistance to chemotherapy, which highlights the requirement for alternative therapies. The chaperone heat shock protein (HSP) 90 assist proteins involved in the onset and progression of ATLL. In the present study, the efficacy of a second generation HSP90 inhibitor termed AUY922 was investigated in ATLL. In vitro, AUY922 induced marked inhibition of cell viability in the HTLV-1-infected T-cell lines HUT-102 and MT-4. In immunodeficient mice bearing HUT-102 xenotransplants, AUY922 markedly retarded tumor growth, compared with the control group. Apoptosis was evident in hematoxylin and eosin stained- and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling-labeled tissue sections from AUY922-treated mice. In addition, AUY922 significantly reduced the serum levels of the surrogate tumor markers soluble interleukin-2 receptor and soluble cluster of differentiation 30. Overall, the present results demonstrate that AUY922 has potent anti-ATLL activity, thus providing a rationale for continuing the clinical development of HSP90 inhibitors in clinical trials for the treatment of patients with ATLL.

Abstract 3132: Dynamic changes of epigenetic abnormalities during initiation and progression of adult T-cell leukemia/lymphoma (ATLL)

Abstract HTLV-1 causes ATLL in 3-5% of infected individuals after a long latent period of 40 to 60 years. ATLL is divided into four stages: namely, smoldering, chronic, lymphoma and acute types. The smoldering and chronic types are indolent, but the acute and lymphoma types are aggressive ATLL characterized by resistance to chemotherapy and a poor prognosis. Such a long latent period suggests that a multi-step leukemogenic/lymphomagenic mechanism is involved in the development of ATLL, although the critical events in the progression have not been characterized. To determine whether epigenetic abnormalities are playing the important role in the progression of ATLL, we analyzed the methylation profiles, showing that number of CpG island methylated genes increased with disease progression and aberrant hyper-methylation in specific genes was detected even in HTLV-1 carriers and correlated with progression to ATLL. The CpG island methylator phenotype (CIMP) was observed most frequently in lymphoma type ATLL and was also closely associated with the progression and crisis of ATLL. The high number of methylated genes and increase of CIMP incidence were shown to be unfavorable prognostic factors and correlated with a shorter overall survival with the Kaplan-Meyer analysis. Dynamic changes of aberrant DNA methylation status in the specific genes were observed during the progression of an ATLL patient. The present findings strongly suggest that the multi-step accumulation of aberrant CpG methylation in specific target genes and the presence of CIMP are deeply involved in the initiation and progression of ATLL not only epidemiologically but also in the clinical course of a specific ATLL patient. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3132. doi:1538-7445.AM2012-3132