Mechanisms of action and resistance in histone methylation-targeted therapy

Epigenomes enable the rectification of disordered cancer gene expression, thereby providing new targets for pharmacological interventions. The clinical utility of targeting histone H3 lysine trimethylation (H3K27me3) as an epigenetic hallmark has been demonstrated1-7. However, in actual therapeutic settings, the mechanism by which H3K27me3-targeting therapies exert their effects and the response of tumour cells remain unclear. Here we show the potency and mechanisms of action and resistance of the EZH1-EZH2 dual inhibitor valemetostat in clinical trials of patients with adult T cell leukaemia/lymphoma. Administration of valemetostat reduced tumour size and demonstrated durable clinical response in aggressive lymphomas with multiple genetic mutations. Integrative single-cell analyses showed that valemetostat abolishes the highly condensed chromatin structure formed by the plastic H3K27me3 and neutralizes multiple gene loci, including tumour suppressor genes. Nevertheless, subsequent long-term treatment encounters the emergence of resistant clones with reconstructed aggregate chromatin that closely resemble the pre-dose state. Acquired mutations at the PRC2-compound interface result in the propagation of clones with increased H3K27me3 expression. In patients free of PRC2 mutations, TET2 mutation or elevated DNMT3A expression causes similar chromatin recondensation through de novo DNA methylation in the H3K27me3-associated regions. We identified subpopulations with distinct metabolic and gene translation characteristics implicated in primary susceptibility until the acquisition of the heritable (epi)mutations. Targeting epigenetic drivers and chromatin homeostasis may provide opportunities for further sustained epigenetic cancer therapies.

EZH1/2 dual inhibitors suppress HTLV-1-infected cell proliferation and hyperimmune response in HTLV-1-associated myelopathy

Background

Human T-cell leukemia virus type 1 (HTLV-1) causes HTLV-1-associated myelopathy (HAM), adult T-cell leukemia/lymphoma (ATL), HTLV-1-associated uveitis, and pulmonary diseases. Although both HAM and ATL show proliferation of infected cells, their pathogeneses are quite different. In particular, the pathogenesis of HAM is characterized by hyperimmune responses to HTLV-1-infected cells. Recently, we demonstrated the overexpression of histone methyltransferase EZH2 in ATL cells and the cytotoxic effects of EZH2 inhibitors and EZH1/2 dual inhibitors on these cells. However, these phenomena have never been studied in HAM. Furthermore, what effect these agents have on the hyperimmune response seen in HAM is completely unknown.

Methods

In this study, we investigated histone methyltransferase expression levels in infected cell populations (CD4⁺ and CD4⁺CCR4⁺ cells) from patients with HAM using microarray and RT-qPCR analyses. Next, using an assay system that utilizes the spontaneous proliferation characteristic of peripheral blood mononuclear cells derived from patients with HAM (HAM-PBMCs), we investigated the effects of EZH2 selective inhibitors (GSK126 and tazemetostat) and EZH1/2 dual inhibitors (OR-S1 and valemetostat, also known as DS-3201), particularly on cell proliferation rate, cytokine production, and HTLV-1 proviral load. We also examined the effect of EZH1/2 inhibitors on the proliferation of HTLV-1-infected cell lines (HCT-4 and HCT-5) derived from patients with HAM.

Results

We found elevated expression of EZH2 in CD4⁺ and CD4⁺CCR4⁺ cells from patients with HAM. EZH2 selective inhibitors and EZH1/2 inhibitors significantly inhibited spontaneous proliferation of HAM-PBMC in a concentration-dependent manner. The effect was greater with EZH1/2 inhibitors. EZH1/2 inhibitors also reduced the frequencies of Ki67⁺ CD4⁺ T cells and Ki67⁺ CD8⁺ T cells. Furthermore, they reduced HTLV-1 proviral loads and increased IL-10 levels in culture supernatants but did not alter IFN-γ and TNF-α levels. These agents also caused a concentration-dependent inhibition of the proliferation of HTLV-1-infected cell lines derived from patients with HAM and increased annexin-V(+)7-aminoactinomycin D(-) early apoptotic cells.

Conclusion

This study showed that EZH1/2 inhibitors suppress HTLV-1-infected cell proliferation through apoptosis and the hyperimmune response in HAM. This indicates that EZH1/2 inhibitors may be effective in treating HAM.

Schlafen 12 restricts HIV-1 latency reversal by a codon-usage dependent post-transcriptional block in CD4+ T cells

Latency is a major barrier towards virus elimination in HIV-1-infected individuals. Yet, the mechanisms that contribute to the maintenance of HIV-1 latency are incompletely understood. Here we describe the Schlafen 12 protein (SLFN12) as an HIV-1 restriction factor that establishes a post-transcriptional block in HIV-1-infected cells and thereby inhibits HIV-1 replication and virus reactivation from latently infected cells. The inhibitory activity is dependent on the HIV-1 codon usage and on the SLFN12 RNase active sites. Within HIV-1-infected individuals, SLFN12 expression in PBMCs correlated with HIV-1 plasma viral loads and proviral loads suggesting a link with the general activation of the immune system. Using an RNA FISH-Flow HIV-1 reactivation assay, we demonstrate that SLFN12 expression is enriched in infected cells positive for HIV-1 transcripts but negative for HIV-1 proteins. Thus, codon-usage dependent translation inhibition of HIV-1 proteins participates in HIV-1 latency and can restrict the amount of virus release after latency reversal.

Long-term safety and efficacy of mogamulizumab (anti-CCR4) for treating virus-associated myelopathy

Some carriers of human T-cell leukemia virus type 1 (HTLV-1), a retrovirus that primarily infects CD4+ T cells and causes lifelong infection, develop HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Current treatments for HAM/TSP are insufficient with problematic long-term side effects. This study evaluated the long-term safety and efficacy of the anti-CCR4 antibody mogamulizumab in patients with HAM/TSP over a 4-year period. We conducted an open-label, extended long-term study (UMIN trial number: UMIN000019942) of a Phase 1-2a trial with mogamulizumab for HAM/TSP (UMIN000012655). The study participants were patients with corticosteroid-resistant HAM/TSP who could walk 10 m with or without assistive tools. Mogamulizumab was administered at 0.01, 0.03, 0.1, or 0.3 mg/kg at intervals of ≥8 weeks (0.01 and 0.03 mg/kg) or ≥12 weeks (0.1 and 0.3 mg/kg). HTLV-1 proviral load, cerebrospinal fluid inflammatory markers, and clinical symptoms were summarized by descriptive statistics. Missing observations were imputed using the last-observation-carried-forward method. As a post-hoc analysis, we evaluated the therapeutic effect of mogamulizumab on gait function by comparing it with contemporary control data from a HAM/TSP patient registry. Of the 21 participants in the Phase 1-2a, 18 (86%) enrolled in the long-term study and 15 (71%) continued repeated doses of mogamulizumab for 4 years. The median dose was 0.1 mg/kg after 4 years. Seventeen of 21 participants (81%) experienced grade 1-2 skin-related adverse events. Observed grade 3 drug-related adverse effects included three cases of lymphopenia and one case each of microscopic polyangiitis, elevated levels of aspartate aminotransferase, and neutropenia. Four of 21 participants (19%) developed neutralizing antibodies. After 4 years, the peripheral blood proviral load and the number of infected cells in CSF decreased by 60.7% and 66.3%, respectively. Neopterin and CXCL10 CSF concentrations decreased by 37.0% and 31.0%, respectively. Among the 18 participants, spasticity and Osame Motor Disability Score (OMDS) improved in 17 (94%) and 4 (22%), respectively. However, 10 m walking time worsened by 7.3% on average. Comparison with the contemporary control group demonstrated that mogamulizumab inhibited OMDS progression (p = 0.02). The results of the study suggest that mogamulizumab has long-term safety and inhibitory effect on lower limb motor disability progression in corticosteroid-treated patients with HAM/TSP. This will provide a basis for the application of mogamulizumab in HAM/TSP treatment.

The role of epigenetics in T-cell lymphoma

Malignant lymphomas are a group of diseases with epigenomic abnormalities fundamental to pathogenesis and pathophysiology. They are characterized by a high frequency of abnormalities related to DNA methylation regulators (DNMT3A, TET2, IDH2, etc.) and histone modifiers (EZH2, HDAC, KMT2D/MLL2, CREBBP, EP300, etc.). These epigenomic abnormalities directly amplify malignant clones. They also originate from a hematopoietic stem cell-derived cell lineage triggered by epigenomic changes. These characteristics are linked to their high affinity for epigenomic therapies. Hematology has led disease epigenetics in the areas of basic research, clinical research, and drug discovery. However, epigenomic regulation is generally recognized as a complex system, and gaps exist between basic and clinical research. To provide an overview of the status and importance of epigenomic abnormalities in malignant lymphoma, this review first summarizes the concept and essential importance of the epigenome, then outlines the current status and future outlook of epigenomic abnormalities in malignant lymphomas.

KRAS mutation in intrahepatic cholangiocarcinoma: Linkage with metastasis-free survival and reduced E-cadherin expression

BACKGROUND AND AIMS

Although KRAS mutations are the major driver of intrahepatic cholangiocarcinoma (ICC), their role remains unexplored. This study aimed to elucidate the prognostic effects, association with clinicopathologic characteristics and potent functions of KRAS mutations in ICC.

METHODS

A hundred and seven resected stage I-III ICCs were analysed for KRAS mutation status and its link with clinicopathological features. An independent validation cohort (n = 138) was included. In vitro analyses using KRAS-mutant ICC cell lines were performed.

RESULTS

KRAS mutation was significantly associated with worse overall survival in stage I-III ICCs, which was validated in an independent cohort. Recurrence-free survival did not significantly differ between cases with and without KRAS mutations, but if limited to recurrence with extrahepatic metastasis, KRAS-mutant cases showed significantly worse distant metastasis-free survival than KRAS-wild cases showed. KRAS mutations were associated with frequent tumour budding with reduced E-cadherin expression. In vitro, KRAS depletion caused marked inhibition of cell growth and migration together with E-cadherin upregulation in KRAS-mutant ICC cells. The RNA-sequencing assay revealed that KRAS depletion caused MYC pathway downregulation and interferon pathway upregulation.

CONCLUSIONS

Our observations suggest that KRAS mutations are associated with aggressive behaviour of ICC, especially the development of extrahepatic metastasis. Mutant KRAS is likely to change the adhesive status of ICC cells, affect the responsiveness of tumour cells to interferon immune signals, and consequently promote extrahepatic metastasis. KRAS mutation status, which predicts the prognoses of patients with ICC after surgical resection, is expected to help stratify patients better for individual postoperative treatment strategies.

RAISING is a high-performance method for identifying random transgene integration sites

Both natural viral infections and therapeutic interventions using viral vectors pose significant risks of malignant transformation. Monitoring for clonal expansion of infected cells is important for detecting cancer. Here we developed a novel method of tracking clonality via the detection of transgene integration sites. RAISING (Rapid Amplification of Integration Sites without Interference by Genomic DNA contamination) is a sensitive, inexpensive alternative to established methods. Its compatibility with Sanger sequencing combined with our CLOVA (Clonality Value) software is critical for those without access to expensive high throughput sequencing. We analyzed samples from 688 individuals infected with the retrovirus HTLV-1, which causes adult T-cell leukemia/lymphoma (ATL) to model our method. We defined a clonality value identifying ATL patients with 100% sensitivity and 94.8% specificity, and our longitudinal analysis also demonstrates the usefulness of ATL risk assessment. Future studies will confirm the broad applicability of our technology, especially in the emerging gene therapy sector.

[The role of epigenetics in malignant lymphoma]

Malignant lymphomas are a group of diseases in which epigenomic abnormalities are fundamental to the pathogenesis and pathophysiology and are characterized by a high frequency of abnormalities in DNA methylation regulators and histone modifiers. These epigenomic abnormalities directly amplify malignant clones. They also originated from a cell lineage differentiated from hematopoietic stem cells through epigenomic changes. These characteristics are associated with their high affinity for epigenomic therapies. Hematology has been a leader in the basic, clinical, and drug discovery areas of disease epigenetics. However, the epigenomic regulation is generally recognized as a complex system, and gaps are observed between basic and clinical studies. To overview the status and importance of "epigenomic abnormalities in malignant lymphoma," this review first summarizes the concept and essential importance of the epigenome and then outlines the current status and future perspective of epigenomic abnormalities in malignant lymphomas.

HTLV-1 infection promotes excessive T cell activation and transformation into adult T cell leukemia/lymphoma

Human T cell leukemia virus type 1 (HTLV-1) mainly infects CD4+ T cells and induces chronic, persistent infection in infected individuals, with some developing adult T cell leukemia/lymphoma (ATL). HTLV-1 alters cellular differentiation, activation, and survival; however, it is unknown whether and how these changes contribute to the malignant transformation of infected cells. In this study, we used single-cell RNA-sequencing and T cell receptor-sequencing to investigate the differentiation and HTLV-1-mediated transformation of T cells. We analyzed 87,742 PBMCs from 12 infected and 3 uninfected individuals. Using multiple independent bioinformatics methods, we demonstrated the seamless transition of naive T cells into activated T cells, whereby HTLV-1-infected cells in an activated state further transformed into ATL cells, which are characterized as clonally expanded, highly activated T cells. Notably, the greater the activation state of ATL cells, the more they acquire Treg signatures. Intriguingly, the expression of HLA class II genes in HTLV-1-infected cells was uniquely induced by the viral protein Tax and further upregulated in ATL cells. Functional assays revealed that HTLV-1-infected cells upregulated HLA class II molecules and acted as tolerogenic antigen-presenting cells to induce anergy of antigen-specific T cells. In conclusion, our study revealed the in vivo mechanisms of HTLV-1-mediated transformation and immune escape at the single-cell level.

Impact of cumulative exposure to LDL cholesterol on cardiovascular events in patients with familial hypercholesterolemia

Aims

Recent studies suggest that cumulative exposure to LDL-cholesterol (LDL-C) leads to the development of atherosclerotic cardiovascular disease (ASCVD). However, few studies have investigated whether this link extends to individuals with familial hypercholesterolemia (FH), a relevant patient population. We aimed to determine whether cholesterol-year-score, an indicator of cumulative exposure to LDL-C, is associated with ASCVD events among Japanese patients with FH

Methods and results

We retrospectively investigated the health records of 1,050 patients with clinical FH diagnosis who were referred to our institute between April 1990 and March 2019. We used Cox proportional hazards models adjusted for established ASCVD risk factors to assess the association between cholesterol-year-score and major adverse cardiovascular events (MACEs), including death from any cause or hospitalization due to ASCVD events. Cholesterol-year-score was calculated as LDL-C max × [age at diagnosis / statin initiation] + LDL-C at inclusion × [age at inclusion − age at diagnosis / statin initiation]. The median follow-up period for MACE evaluation was 12.3 (interquartile range, 9.1–17.5) years, and 177 patients experienced MACEs during the observation period. Cholesterol-year-score was significantly associated with MACEs (hazard ratio [HR], 1.35; 95% confidence interval, 1.07–1.53; P=0.0034, per 1,000 mg-year/dL), independent of other traditional risk factors including age and LDL-C, based on cross-sectional assessment. Cholesterol-year-score improved the discrimination ability of other traditional risk factors for ASCVD events (C-index, 0.901 versus 0.889; P=0.00473).

Conclusion

Cumulative LDL-C exposure was strongly associated with MACEs in Japanese patients with FH, warranting early diagnosis and treatment initiation in these patients.

Funding Acknowledgement

Type of funding sources: None.

POS0730 DECREASED RISK OF OSTEONECROSIS OVER TIME IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS USING JAPANESE HEALTH INSURANCE DATABASE

Background:

In patients with systemic lupus erythematosus (SLE), prevalence of osteonecrosis (ON) was 20–40% 1, and 4–10 times higher risk of ON than the general population was observed 2,3. Because ON can influence patients’ physical activity and quality of life, it is essential for rheumatologists to manage ON appropriately. Recently, medications such as mycophenolate mofetil (MMF) and hydroxychloroquine (HCQ) were approved for SLE in Japan. Considering the changes in treatments for SLE over time, it is clinically important to investigate the risk and risk factors of ON in patients with the disease. However, to date, only evidence is found in the literature.

Objectives:

To estimate incidence rate (IR) and identify risk factors of ON in patients with SLE using a Japanese health insurance database.

Methods:

This retrospective longitudinal population-based study was conducted using claims data provided by Medical Data Vision Co., Ltd (Tokyo, Japan). We defined individuals as SLE cases if they met all of the following: 1) having at least one ICD10 code (M321 or M329); 2) having at least one prescription of oral corticosteroids (CS), methylprednisolone (mPSL) pulse therapy, immunosuppressive drugs (IS) (azathioprine, mizoribine, tacrolimus, MMF, cyclophosphamide, methotrexate), biologics (belimumab, rituximab) or HCQ between January 2010 and January 2017; 3) being 16 years old or over. The start of observation was defined by the first month in which cases met all of the above criteria. Patients were followed until the earliest of date of first ON, date of loss of follow-up, or the end of follow-up (December 2017). ON was defined when patients had at least one ICD code (M87.0, M87.1, M87.2, M87.3, M87.8, M87.9, M90.5) during the observation period. Patients were excluded if they had a previous diagnosis of ON during the first 3 months of the observation period. We defined baseline characteristics using the data in the month of starting observation, and calculated incidence rate (IR) in each year, adjusted relative risk (RR [95% CI]) of ON using a Poisson regression model, and adjusted odds ratio (OR [95% CI]) of risk factors of ON after adjusting for age and sex at baseline, and medications and comorbidities during the observation period using a logistic regression model.

Results:

In this study, 16,386 cases were included. The median age was 55 years and 81.3% were female. Median observation period was 33 months, and total observation period was 47,138 patient-years (PY). IR/1,000 PY of ON in each year from 2010 to 2017 was 13.2, 10.6, 11.0, 13.3, 13.1, 9.8, 8.5, and 7.3, respectively. Adjusted RR in each year from 2011 to 2017 compared to 2010 was 0.5 [0.2–1.4], 0.3 [0.1–0.9], 0.6 [0.3–1.4], 0.7 [0.3–1.6], 0.4 [0.2–0.8], 0.4 [0.2–0.8], and 0.3 [0.1–0.7], respectively. Adjusted OR was 1.22 [1.10–1.34] for younger age by decade, 1.41 [1.11–1.79] for male, 2.69 [1.52–4.76] for use of oral CS (> 0 and < 5 mg/day of prednisolone [PSL] equivalent dose versus no use), 2.21 [1.26–3.86] for oral CS (≥ 5 and < 10mg/day versus no use), and 1.25 [1.02–1.54] for dyslipidemia.

Conclusion:

Significant decrease in IR of ON after 2015 was observed in Japanese patients with SLE for the first time. Younger age, use of CS, and dyslipidemia were identified as significant risk factors of ON.

References:

[1]Rheumatology 2018;57(5):844-9.

[2]BMJ Open. 2017;7(7):e016788.

[3]Eur J Intern Med. 2016;35:e23-e4.

Disclosure of Interests:

Ryoko Sakai Speakers bureau: RS received fees from Bristol Myers Squibb Co., Ltd., Grant/research support from: Tokyo Women’s Medical University (TWMU), particularly the Division of Multidisciplinary Management of Rheumatic Diseases, Department of Rheumatology, has received unrestricted research grants from Ayumi Pharmaceutical Co.; Chugai Pharmaceutical Co., Ltd.; Eisai Co., Ltd., Nippon Kayaku Co., Ltd.; Taisho Toyama Pharmaceutical Co., Ltd.; Takeda Pharmaceutical Co., Ltd.; Mitsubishi Tanabe Pharma Co.; and Teijin Pharma Ltd., with which TWMU paid the salaries of RS., Eiichi Tanaka Speakers bureau: ET has received lecture fees from Abbvie, Asahi Kasei pharma co., Astellas Pharmaceutical, Ayumi Pharmaceutical, Chugai Pharmaceutical, Eisai Pharmaceutical, Eli Lilly Japan K.K., GlaxoSmithKline K.K., Kyowa Pharma Chemical CO.,LTD., Janssen Pharmaceutical K.K., Mochida Pharmaceutical CO.,LTD., Pfizer, Takeda Pharmaceutical, and Teijin Pharma Ltd., Consultant of: ET has received lecture fees from Abbvie, Asahi Kasei pharma co., Astellas Pharmaceutical, Ayumi Pharmaceutical, Chugai Pharmaceutical, Eisai Pharmaceutical, Eli Lilly Japan K.K., GlaxoSmithKline K.K., Kyowa Pharma Chemical CO.,LTD., Janssen Pharmaceutical K.K., Mochida Pharmaceutical CO.,LTD., Pfizer, Takeda Pharmaceutical, and Teijin Pharma Ltd., Miku Yamagishi: None declared, masako majima: None declared, masayoshi harigai Speakers bureau: MH has received speaker’s fee from AbbVie Japan GK, Ayumi Pharmaceutical Co., Boehringer Ingelheim Japan, Inc., Bristol Myers Squibb Co., Ltd., Chugai Pharmaceutical Co., Ltd., Eisai Co.,Ltd., Eli Lilly Japan K.K., GlaxoSmithKline K.K., Kissei Pharmaceutical Co., Ltd., Pfizer Japan Inc., Takeda Pharmaceutical Co., Ltd., and Teijin Pharma Ltd., Consultant of: MH is a consultant for AbbVie, Boehringer-ingelheim, Bristol Myers Squibb Co., Kissei Pharmaceutical Co., Ltd. and Teijin Pharma., Grant/research support from: MH has received research grants from AbbVie Japan GK, Asahi Kasei Corp., Astellas Pharma Inc., Ayumi Pharmaceutical Co., Bristol Myers Squibb Co., Ltd., Chugai Pharmaceutical Co., Daiichi-Sankyo, Inc., Eisai Co., Ltd., Kissei Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Nippon Kayaku Co., Ltd., Sekisui Medical, Shionogi & Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Ltd., and Teijin Pharma Ltd.

Prognostic impact of cascade screening for familial hypercholesterolemia on cardiovascular events

Background

Early diagnosis and timely treatment for the patients with familial hypercholesterolemia (FH) can substantially lower the risk of atherosclerotic cardiovascular disease (ASCVD). In this sense, cascade screening could be one of the most useful options. However, few data exist regarding the impact of cascade screening for FH on the reduction of risk of ASCVD events.

Objectives

We aimed to evaluate the prognostic impact of cascade screening for FH.

Methods

We retrospectively investigated the health records of 1,050 patients with clinically diagnosed FH, including probands and their relatives who were cascade-screened. We used Cox models that were adjusted for established ASCVD risk factors to assess the association between cascade screening and major adverse cardiovascular events (MACE). The median period of follow-up was 12.3 years (interquartile range [IQR] = 9.1–17.5 years), and MACE included death from any causes or hospitalization due to ASCVD events.

Results

During the observation period, 246 participants experienced MACE. The mean age of patients identified through cascade screening was 18-years younger than that of the probands (38.7 yr vs. 57.0 yr, P&lt;0.001), with a lower proportion of ASCVD risk factors. Interestingly, patients identified through cascade screening under milder lipid-lowering therapies were at reduced risk for MACE (hazard ratio [HR] = 0.36; 95% CI = 0.22 to 0.60; P&lt;0.001) when compared with the probands, even after adjusting for those known risk factors.

Conclusions

The identification of patients with FH via cascade screening appeared to result in better prognoses.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Scientific research grants from the Ministry of Education, Science and Culture of Japan (no. 16K19394, 18K08064, and 19K08575)

Targeting Excessive EZH1 and EZH2 Activities for Abnormal Histone Methylation and Transcription Network in Malignant Lymphomas

Although global H3K27me3 reprogramming is a hallmark of cancer, no effective therapeutic strategy for H3K27me3-high malignancies harboring EZH2^WT/WT has yet been established. We explore epigenome and transcriptome in EZH2^WT/WT and EZH2^WT/Mu aggressive lymphomas and show that mutual interference and compensatory function of co-expressed EZH1 and EZH2 rearrange their own genome-wide distribution, thereby establishing restricted chromatin and gene expression signatures. Direct comparison of leading compounds introduces potency and a mechanism of action of the EZH1/2 dual inhibitor (valemetostat). The synthetic lethality is observed in all lymphoma models and primary adult T cell leukemia-lymphoma (ATL) cells. Opposing actions of EZH1/2-polycomb and SWI/SNF complexes are required for facultative heterochromatin formation. Inactivation of chromatin-associated genes (ARID1A, SMARCA4/BRG1, SMARCB1/SNF5, KDM6A/UTX, BAP1, KMT2D/MLL2) and oncovirus infection (HTLV-1, EBV) trigger EZH1/2 perturbation and H3K27me3 deposition. Our study provides the mechanism-based rationale for chemical dual targeting of EZH1/2 in cancer epigenome.

A high-throughput detection method for the clonality of Human T-cell leukemia virus type-1-infected cells in vivo

Approximately 10-20 million of Human T-cell leukemia virus type-1 (HTLV-1)-infected carriers have been previously reported, and approximately 5% of these carriers develop adult T-cell leukemia/lymphoma (ATL) with a characteristic poor prognosis. In Japan, Southern blotting has long been routinely performed for detection of clonally expanded ATL cells in vivo, and as a confirmatory diagnostic test for ATL. However, alternative methods to Southern blotting, such as sensitive, quantitative, and rapid analytical methods, are currently required in clinical practice. In this study, we developed a high-throughput method called rapid amplification of integration site (RAIS) that could amplify HTLV-1-integrated fragments within 4 h and detect the integration sites in > 0.16% of infected cells. Furthermore, we established a novel quantification method for HTLV-1 clonality using Sanger sequencing with RAIS products, and the validity of the quantification method was confirmed by comparing it with next-generation sequencing in terms of the clonality. Thus, we believe that RAIS has a high potential for use as an alternative routine molecular confirmatory test for the clonality analysis of HTLV-1-infected cells.

Sequentially addressable dielectrophoretic array for high-throughput sorting of large-volume biological compartments

Droplet microfluidics has become a powerful tool in precision medicine, green biotechnology, and cell therapy for single-cell analysis and selection by virtue of its ability to effectively confine cells. However, there remains a fundamental trade-off between droplet volume and sorting throughput, limiting the advantages of droplet microfluidics to small droplets (<10 pl) that are incompatible with long-term maintenance and growth of most cells. We present a sequentially addressable dielectrophoretic array (SADA) sorter to overcome this problem. The SADA sorter uses an on-chip array of electrodes activated and deactivated in a sequence synchronized to the speed and position of a passing target droplet to deliver an accumulated dielectrophoretic force and gently pull it in the direction of sorting in a high-speed flow. We use it to demonstrate large-droplet sorting with ~20-fold higher throughputs than conventional techniques and apply it to long-term single-cell analysis of Saccharomyces cerevisiae based on their growth rate.

CD4+ CADM1+ cell percentage predicts disease progression in HTLV-1 carriers and indolent adult T-cell leukemia/lymphoma

We recently took advantage of the universal expression of cell adhesion molecule 1 (CADM1) by CD4⁺ cells infected with HTLV‐1 and the downregulation of CD7 expression that corresponds with the oncogenic stage of HTLV‐1‐infected cells to develop a flow cytometric system using CADM1 versus CD7 plotting of CD4⁺ cells. We risk‐stratified HTLV‐1 asymptomatic carriers (AC) and indolent adult T‐cell leukemia/lymphoma (ATL) cases based on the CADM1⁺ percentage, in which HTLV‐1‐infected clones are efficiently enriched. AC and indolent ATL cases were initially classified according to their CADM1⁺ cell percentage. Follow‐up clinical and flow cytometric data were obtained for 71 cases. In G1 (CADM1⁺ ≤ 10%) and G2 (10% < CADM1⁺ ≤ 25%) cases, no apparent clinical disease progression was observed. In G3 (25% < CADM1⁺ ≤ 50%) cases, five out of nine (55.5%) cases progressed from AC to smoldering‐type ATL. In G4 (50% < CADM1⁺) cases, the cumulative incidence of receiving systemic chemotherapy at 3 years was 28.4%. Our results indicate that the percentage of the CD4⁺CADM1⁺ population predicts clinical disease progression: G1 and G2 cases, including AC cases, are stable and considered to be at low risk; G3 cases, including advanced AC cases and smoldering‐type ATL cases based on the Shimoyama criteria, are considered to have intermediate risk; and G4 cases, which are mainly indolent ATL cases, are unstable and at high risk of acute transformation.

Correlation of two distinct metastasis-associated proteins, MTA1 and S100A4, in angiogenesis for promoting tumor growth

Extensive studies on metastasis-associated proteins, S100A4 and MTA1, have been carried out for over two decades, but correlation of both proteins remains obscure. Here we show evidence for the correlation in angiogenesis. First, silencing of each protein by siRNA-mediated knockdown in mouse endothelial MSS31 cells resulted in the inhibition of tube formation. Unexpectedly, the knockdown of MTA1 affected not only its own expression but also the expression of S100A4, whereas silencing of S100A4 did not affect the MTA1 expression. Additionally, non-muscle myosin IIA (NMIIA) phosphorylation, which was partly controlled by S100A4, was found to be upregulated by knockdown of both proteins in MSS31 cells. Moreover, cycloheximide treatment of MSS31 cells revealed that the rate of S100A4 degradation was accelerated by MTA1 knockdown. This finding, together with our observation that cytoplasmic MTA1, but not nuclear MTA1, was colocalized with S100A4, suggested the involvement of MTA1 in S100A4 stability. The direct in vivo angiogenesis assay showed that both protein siRNAs provoked a significant inhibition of new blood vessel formation induced by angiogenic factors, indicating their anti-angiogenic activities. Treatment of human pancreatic tumor (PANC-1) xenograft in mice with mMTA1 siRNA resulted in tumor regression via suppression of angiogenesis in vivo, as also observed in the case of human prostate cancer xenograft treated with mS100A4 siRNA. Taken together, these data led us to conclude that the MTA1-S100A4-NMIIA axis exists in endothelial cells as a novel pathway in promoting tumor vascular formation and could be a target for suppressing tumor growth and metastasis.

HTLV-1-Mediated Epigenetic Pathway to Adult T-Cell Leukemia-Lymphoma

Human T-cell leukemia virus type 1 (HTLV-1), the first reported human oncogenic retrovirus, is the etiologic agent of highly aggressive, currently incurable diseases such as adult T-cell leukemia-lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1 proteins, including Tax and HBZ, have been shown to have critical roles in HTLV-1 pathogenicity, yet the underlying mechanisms of HTLV-1-driven leukemogenesis are unclear. The frequent disruption of genetic and epigenetic gene regulation in various types of malignancy, including ATL, is evident. In this review, we illustrate a focused range of topics about the establishment of HTLV-1 memory: (1) genetic lesion in the Tax interactome pathway, (2) gene regulatory loop/switch, (3) disordered chromatin regulation, (4) epigenetic lock by the modulation of epigenetic factors, (5) the loss of gene fine-tuner microRNA, and (6) the alteration of chromatin regulation by HTLV-1 integration. We discuss the persistent influence of Tax-dependent epigenetic changes even after the disappearance of HTLV-1 gene expression due to the viral escape from the immune system, which is a remaining challenge in HTLV-1 research. The summarized evidence and conceptualized description may provide a better understanding of HTLV-1-mediated cellular transformation and the potential therapeutic strategies to combat HTLV-1-associated diseases.

HIV LTR-Driven Antisense RNA by Itself Has Regulatory Function and May Curtail Virus Reactivation From Latency

Latently infected T lymphocytes are an important barrier toward eliminating a persistent HIV infection. Here we describe an HIV-based recombinant fluorescent-lentivirus referred to as “rfl-HIV” that enables to analyze sense and antisense transcription by means of fluorescence reporter genes. This model virus exhibited similar transcriptional and functional properties of the antisense transcript as observed with a wild type HIV, and largely facilitated the generation of latently-infected T cells clones. We show that latently-infected cells can be divided into two types, those with and those without antisense transcription. Upon addition of latency reversal agents, only the cells that lack antisense transcripts are readily reactivated to transcribe HIV. Thus, antisense transcripts may exhibit a dominant suppressor activity and can lock an integrated provirus into a non-reactivatable state. These findings could have important implications for the development of strategies to eradicate HIV from infected individuals.

[Epigenetic aberrations in adult T-cell leukemia/lymphoma and development of a novel EZH1/2 inhibitor]

Histone H3 lysine 27 tri-methylation (H3K27me3) -dependent transcription regulation is a fundamental process of gene control. Although EZH2 mutation is observed in certain lymphoma types, many other cancers show global H3K27me3 accumulation irrespective of mutation. However, the underlying mechanisms of gene silencing and therapeutic efficacies of epigenetic drugs remain unclear. In this study, we showed that globally-accumulated H3K27me3 is induced by both cis-bound EZH1 and EZH2 in mature lymphocyte-derived malignancies. Mutual interference and compensatory functions of co-expressed EZH1/2 rearrange the genome-wide distribution, establishing restricted chromatin and gene expression signatures. Using novel EZH1/2 dual inhibitors, we found that both EZH1 and EZH2 are required for the maintenance and induction of H3K27me3. The synthetic lethality of targeting EZH1 and EZH2 was observed in lymphoma models and primary adult T-cell leukemia/lymphoma (ATL) cells harboring H3K27me3 accumulation. This heritable EZH1/2 dysfunctional state was epigenetically imprinted at the virus-infected, immortalized phase. EZH1/2 dual inhibition could eliminate infected cell populations more effectively than EZH2 inhibition. Regarding the frequent observation of H3K27me3 accumulation in advanced-stage and early-phase malignant progenitors, the emerging EZH1- and EZH2-dependent epigenetic reprograming is an incipient process of fate decision within developmental pathways of cancers.

EVI1 modulates oncogenic role of GPC1 in pancreatic carcinogenesis

Glypican-1 (GPC1) protein in exosomes was recently identified as a biomarker for the early detection of pancreatic ductal adenocarcinoma (PDAC). Immunohistochemical analyses and in vitro assays were conducted to assess the usefulness of GPC1 as a PDAC biomarker, to reveal the biological role of GPC1 in pancreatic carcinogenesis, and to ascertain the regulation mechanism of GPC1. An aberrant overexpression of GPC1 protein which is usually absent in normal pancreatic duct, was a widespread marker across the full spectrum of human PDAC precursors, PDAC, and pancreatic cancerous stroma. In intraductal papillary-mucinous neoplasms (IPMNs), GPC1 tended to be positive in gastric-type IPMN. KRAS mutations were found in all GPC1-positive IPMN cases and in one-third of GPC1-negative IPMN cases. In pancreatic cell lines, GPC1 depletion caused remarkable inhibition of cell growth and migration, suggesting its oncogenic roles. GPC1 depletion upregulated the molecules associated with cell cycle arrest in pancreatic cell lines. Furthermore, KRAS and ecotropic viral integration site 1 (EVI1) oncoprotein upregulated GPC1 expression. In a clinical cohort, GPC1 overexpression was not correlated with pancreatic cancer prognosis. Taken together, these findings suggest the necessity of establishing a threshold of GPC1 value for detecting pancreatic malignancy because GPC1 is overexpressed even in low-grade PDAC precursors which do not always become malignant. Our study also reveals a new aspect of pancreatic carcinogenesis: KRAS and EVI1, two important molecules in early phases of pancreatic carcinogenesis, positively regulate GPC1 expression and likely promote pancreatic carcinogenesis.

Homeostatically Maintained Resting Naive CD4+ T Cells Resist Latent HIV Reactivation

Homeostatic proliferation (HSP) is a major mechanism by which long-lived naïve and memory CD4⁺ T cells are maintained in vivo and suggested to contribute to the persistence of the latent HIV-1 reservoir. However, while many in vitro latency models rely on CD4⁺ T cells that were initially differentiated via T-cell receptor (TCR) stimulation into memory/effector cells, latent infection of naïve resting CD4⁺ T cells maintained under HSP conditions has not been fully addressed. Here, we describe an in vitro HSP culture system utilizing the cytokines IL-7 and IL-15 that allows studying latency in naïve resting CD4⁺ T cells. CD4⁺ T cells isolated from several healthy donors were infected with HIV pseudotypes expressing GFP and cultured under HSP conditions or TCR conditions as control. Cell proliferation, phenotype, and GFP expression were analyzed by flow cytometry. RNA expression was quantified by qRT-PCR. Under HSP culture conditions, latently HIV-1 infected naïve cells are in part maintained in the non-dividing (= resting) state. Although a few HIV-1 provirus⁺ cells were present in these resting GFP negative cells, the estimated level of GFP transcripts per infected cell seems to indicate a block at the post-transcriptional level. Interestingly, neither TCR nor the prototypic HDAC inhibitor SAHA were able to reactivate HIV-1 provirus from these cells. This lack of reactivation was not due to methylation of the HIV LTR. These results point to a mechanism of HIV control in HSP-cultured resting naïve CD4⁺ T cells that may be distinct from that in TCR-stimulated memory/effector T cells.

One-hour plasma glucose as a predictor of the development of Type 2 diabetes in Japanese adults

AIMS

To test the hypothesis that 1-h plasma glucose in an oral glucose tolerance test is a better predictor of the development of diabetes than 2-h plasma glucose, independently of indices of insulin secretion or action in Japanese adults.

METHODS

A historical cohort study was conducted in 1445 Japanese workers who did not have diabetes. The association between 1-h plasma glucose and the development of Type 2 diabetes was analysed.

RESULTS

Overall, 95 of the study participants developed Type 2 diabetes during a mean follow-up of 4.5 years. The area under the receiver-operating characteristic curve for 1-h plasma glucose for future diabetes [0.88 (95% CI 0.84-0.91)] was greater than that for 2-h plasma glucose [0.79 (95% CI 0.74-0.84)], and for insulinogenic [0.73 (95% CI 0.68-0.78)] and disposition indices [0.79 (95% CI 0.74-0.84); P < 0.05]. Compared with the first quartile, the hazard ratio for future diabetes in the fourth quartile of 1-h plasma glucose was 42.5 [95% CI 5.7-315.2 (P < 0.05)] and the hazard ratio in the fourth quartile of 2-h plasma glucose was 4.4 [95% CI 1.8-10.8 (P < 0.05)], after adjustments for covariates including fasting plasma glucose. The significance of the elevated hazard ratio in the fourth quartile of 1-h plasma glucose was maintained after adjustments for 2-h plasma glucose, insulinogenic index or disposition index, whereas the elevation of the hazard ratio in the fourth quartile of 2-h plasma glucose was diminished and was no longer significant after adjustments for 1-h plasma glucose.

CONCLUSIONS

One-hour plasma glucose had a greater association with the future development of Type 2 diabetes than did 2-h plasma glucose, independently of oral glucose tolerance test-derived indices of insulin action in a Japanese population.

Coordinated loss of microRNA group causes defenseless signaling in malignant lymphoma

Biological robustness is exposed to stochastic perturbations, which should be controlled by intrinsic mechanisms; the promiscuous signaling network without appropriate alleviation is the true nature of cancer cells. B cell receptor (BCR) signaling is a major source of gene expression signature important for B cell. It is still unclear the mechanism by which the expression of functionally important genes is continuously deregulated in malignant lymphomas. Using RISC-capture assay, we reveal that multiple BCR signaling factors are persistently regulated by microRNA (miRNA) in human B cells. Clinical samples from patients with diffuse large B-cell lymphoma (DLBCL, n = 83) show loss of an essential miRNA set (miR-200c, miR-203, miR-31). Conventional screening and RISC profiling identify multiple targets (CD79B, SYK, PKCβII, PLCγ1, IKKβ, NIK, MYD88, PI3K class I (α/β/δ/γ), RasGRP3); signaling network habitually faces interference composed by miRNA group in normal B cells. We demonstrate that simultaneous depletion of the key miRNAs enhances translation of the multiple targets and causes chronic activation of NF-κB, PI3K-Akt, and Ras-Erk cascades, leading to B cell transformation. This study suggests that compensatory actions by multiple miRNAs rather than by a single miRNA ensure robustness of biological processes.