Hiroaki Kitamura

Effector Regulatory T Cells Reflect the Equilibrium between Antitumor Immunity and Autoimmunity in Adult T-cell Leukemia.

Anti-CCR4 treatment of ATL destroys leukemic and normal Tregs, which can lead to autoimmunity. Only leukemic Tregs expressed CADM1, distinguishing the two populations. Treg depletion was associated with autoimmunity and Treg reemergence with relapse of ATL. The regulatory T cells (Treg) with the most potent immunosuppressive activity are the effector Tregs (eTreg) with a CD45RA–Foxp3++CCR4+ phenotype. Adult T-cell leukemia (ATL) cells often share the Treg phenotype and also express CCR4. Although mogamulizumab, a monoclonal antibody to CCR4, shows marked antitumor effects against ATL and peripheral T-cell lymphoma, concerns have been raised that it may induce severe autoimmune immunopathology by depleting eTregs. Here, we present case reports for two patients with ATL who responded to mogamulizumab but developed a severe skin rash and autoimmune brainstem encephalitis. Deep sequencing of the T-cell receptor revealed that ATL cells and naturally occurring Tregs within the cell population with a Treg phenotype can be clearly distinguished according to CADM1 expression. The onset of skin rash and brainstem encephalitis was coincident with eTreg depletion from the peripheral blood, whereas ATL relapses were coincident with eTreg recovery. These results imply that eTreg numbers in the peripheral blood sensitively reflect the equilibrium between antitumor immunity and autoimmunity, and that mogamulizumab might suppress ATL until the eTreg population recovers. Close monitoring of eTreg numbers is crucial if we are to provide immunomodulatory treatments that target malignancy without severe adverse events. Cancer Immunol Res; 4(8); 644–9. ©2016 AACR.

Therapeutic management in cardiac lymphoma

1 Division of Hematology, Respiratory Medicine and Oncology, Department of Internal Medicine, 2 Department of Medical Science Technology, School of Health Sciences at Fukuoka, International University of Health and Welfare, Fukuoka, Japan, 3 Department of Thoracic and Cardiovascular Surgery, 4 Division of Cardiology, Department of Internal Medicine 5 Department of Laboratory and Blood Transfusion Medicine, Faculty of Medicine, Saga University, Saga, Japan and 6 Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan

Diffuse bone marrow uptake of fluorodeoxyglucose in a patient with aleukaemic acute lymphoblastic leukaemia

A 61-year-old woman presented with fever, right shoulder pain and back pain. A computerized tomography (CT) scan of the chest demonstrated a nodule with spiculations and pleural indentation in the right lower lobe, suggestive of lung cancer. She was referred to the respiratory medicine service for lung cancer diagnosis and staging. On physical examination neither hepatosplenomegaly nor lymphadenopathy was noted. Her blood test results showed a haemoglobin concentration 130 g/l, white blood cell count 3 9 9 10/l (59 4% neutrophils, 0 8% basophils, 1 5% eosinophils, 9 9% monocytes and 28 4% lymphocytes) and platelet count 148 9 10/l. Carcinoembryonic antigen was slightly elevated. The patient underwent F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT for surveillance of metastatic disease. Unexpectedly, diffuse homogeneous bone marrow FDG uptake was noted (left). An imprint from a bone marrow trephine biopsy specimen after a dry tap showed a markedly hypercellular marrow with diffuse infiltration by leukaemic blasts (right). Repeated bone marrow aspirate films performed after a 5-d constant infusion of cytarabine showed 80% myeloperoxidase-negative lymphoblasts, which were positive for CD19, CD10, CD34, CD33 and CD13. Reverse transcription-polymerase chain reaction analysis detected a minor BCR-ABL1 transcript. A diagnosis of Ph+ aleukaemic acute lymphoblastic leukaemia was made. She received dasatinib plus cyclophosphamide, daunorubicin and vincristine, which resulted in complete remission of leukaemia and disappearance of her symptoms. Diffuse bone marrow FDG uptake has been reported in association with a hyperplastic bone marrow, including during marrow recovery after chemotherapy, following administration of marrow stimulating cytokines (granulocyte colonystimulating factor, granulocyte-macrophage colony-stimulating factor or erythropoietin), as a result of cytokine-producing tumours and in haematological disorders. We took advantage of the PET imaging to diagnose leukaemia in a patient who had no circulating blast cells. A ‘superscan’ (or beautiful bone scan) refers to the intense symmetric activity in the bones on a Tc bone scan, which indicates diffuse underlying skeletal pathology, such as metabolic bone disease or diffuse metastatic disease. We suggest that a superscan-like image on a PET may indicate occult leukaemia.

Successful Autologous Hematopoietic Stem Cell Transplantation Followed by Bortezomib Maintenance in a Patient with Relapsed CD138-low Multiple Solitary Plasmacytomas Harboring a 17p Deletion

Solitary bone plasmacytoma (SBP) tends to progress to multiple myeloma (MM); however, progression to multiple solitary plasmacytomas (MSP) is rare. We report a case of CD138-low MSP with 17p deletion in a patient with relapsed SBP. 17p deletion is associated with a poor outcome in patients with MM, and the low expression of CD138 in myeloma cells is associated with drug resistance and a poor prognosis. The patient was successfully treated with bortezomib plus dexamethasone induction therapy and autologous hematopoietic stem cell transplantation followed by bortezomib maintenance therapy. Consequently, bortezomib treatment was stopped and a stringent complete response has been maintained.

Acute myeloid leukemia with t(19;21)(q13;q22) and marked eosinophilia

Dear Editor, Translocation (19;21)(p13;q22) has only once been previously reported, in one case of radiation-associated acute myeloid leukemia (AML) [1]. Here, we report the first case of AML with t(19;21)(q13;q22) and marked eosinophilia. A 58-year-old man was admitted because of severe anemia. His white blood cell (WBC) count was 6.7 × 10/L, with 42% eosinophils, 1% myeloblasts, and 1.5% erythroblasts (Fig. 1a). The hemoglobin concentration was 49 g/L, and the platelet count was 196 × 10/L. Bone marrow aspiration showed myeloid dysplasia with 4.8% myeloblasts and 22.4% eosinophils (Fig. 1b). The patient was diagnosed temporarily with myelodysplastic syndrome, unclassifiable (MDS-U). Cytogenetic analysis revealed the karyotype 45, X, -Y, t(19;21)(p13;q22) in 17/20 of the metaphases examined (Fig. 1c). Fluorescence in situ hybridization analysis showed three RUNX1 signals and two RUNX1T1 signals in 37% of cells, but no signals corresponding to RUNX1-RUNX1T1 gene fusion (Fig. 1d). As the fusion transcript termed RUNX1AMP19 has been isolated from an AML patient with a t(19;21)(q13;q22) [2], RT-PCR of RUNX1-AMP19 fusion gene was performed; however, the transcripts were not detected. As the patient’s symptoms were improved by transfusions, he was discharged from hospital and closely monitored for disease progression. The peripheral blood (PB) eosinophil count diminished over time. Two months later, anemia and thrombocytopenia progressed. Transformation to AML was confirmed by the increasing blast counts in the bone marrow (64%; Fig. 1e). After two courses of ineffective chemotherapy, pancytopenia and transfusion dependency remained because normal hematopoiesis was suppressed by increasing numbers of blasts. Thereafter, the patient developed septic shock due to Klebsiella pneumonia infection. His clinical condition recovered after intensive treatment for the infection, but, 2 weeks later, the patient died from pontine hemorrhage due to severe thrombocytopenia. In the present case, because the duration from diagnosis of MDS to diagnosis of AML was very short (2 months), the marked eosinophilia could be considered one of the accompanying symptoms at the onset of AML. The decrease in the proportion of eosinophils observed thereafter could have been due to immature blasts outnumbering eosinophils. Although RUNX1-AMP19 fusion transcript was cloned from an AML patient with a t(19;21)(q13;q22) [2], this fusion gene was not detected in the present patient. Identification of chimeric gene in our case is an interesting subject in the future. Both the first reported case [1] and the present case showed loss of sex chromosome (LOS). LOS is one of the most common recurrent cytogenetic abnormalities observed in t(8;21) AML [3]. Several studies suggest that LOS leads to decreased expression of the GM-CSF receptor, located on the pseudoautosomal regions of the sex chromosomes, and is an additional event required for transformation to full-blown leukemia [4–6]. Thus, LOS could also be an important event for the leukemic transformation in t(19;21) AML. As interleukin (IL)-3Rα, GM-CSFRα, and IL-5Rα chain share a commonβ subunit (cβ) [7, 8], and IL-5 is a major regulator of eosinophils, it is feasible that insufficient expression of GM-CSFRα could induce greater occupation of the cβ by IL-5Rα, * Yasushi Kubota kubotay@cc.saga-u.ac.jp

Abstract 3730: The PPM1D inhibitor GSK2830371 has p53-dependent anti-lymphoma effects and enhances bortezomib-induced apoptosis in mantle cell lymphoma

p53 mutations are relatively rare (∼15%) in mantle cell lymphoma (MCL). Chemotherapeutic agents induce DNA damage, p53 phosphorylation and pro-apoptotic wild-type (WT) p53 signaling, resulting in lymphoma cell death. However, DNA damaging agents may have severe acute toxicities, accelerate clonal evolution and cause therapy-related neoplasms by adding new mutations to the original clones. PPM1D is a serine/threonine phosphatase that negatively regulates key DNA damage response proteins including p53, CHK2, Histone H2AX, and ATM. PPM1D has been thought to be an oncogenic protein. It has been reported that PPM1D is overexpressed or amplified in breast and ovarian cancers. GSK2830371 (GSK) is a PPM1D inhibitor, which binds to a flap subdomain that regulates enzymatic activity of PPM1D and substrate recognition (Nat Chem Biol 2014). Treatment of tumor cells with the inhibitor GSK has been found to increase phosphorylation of PPM1D substrates and cause growth inhibition in tumor cells harboring wild-type p53. We investigated the clinical significance of PPM1D and anti-lymphoma effects of GSK in MCL. The mRNA expression levels in patient samples were determined using Oncomine. Our gene expression analyses showed an increase in PPM1D mRNA expression in MCL samples versus normal naive B lymphocytes (P = 0.044) that are the normal counterparts of MCL. PPM1D mRNA levels were positively correlated with CCND1 (encoding Cyclin D1) mRNA levels (r = 0.33, P = 0.0014) and proliferation signature averages (r = 0.54, P Citation Format: Kensuke Kojima, Mariko Yoshimura, Aya Maeda, Hiroaki Kitamura, Yuki Nishida, Shinya Kimura. The PPM1D inhibitor GSK2830371 has p53-dependent anti-lymphoma effects and enhances bortezomib-induced apoptosis in mantle cell lymphoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3730.

Abstract 2938: BMI-1 inhibition by PTC-209 induces mitochondrial apoptosis in acute myeloid leukemia cells

Leukemia stem cells play important roles in leukemia initiation, progression, and relapse, and represent a critical target for therapeutic intervention. BMI-1 is essential for the self-renewal of normal hematopoietic and leukemia stem cells. High expression of BMI-1 has been associated with poor prognosis in AML. PTC-209 is a novel transcriptional inhibitor of BMI-1, which has been reported to exhibit antitumor activity against cancer-initiating cells in colorectal cancer. We investigated anti-leukemia effects of the BMI-1 inhibitor PTC-209 on AML cells. A total of 8 AML cell lines (MOLM-13, OCI-AML3, MV4-11, NB4, HL-60, U-937, MOLM-14, OCI-AML2) were treated with different concentrations of PTC-209 for 48 hours and the IC50 values (concentration at which cell growth is inhibited by 50% at 48 hours of exposure) and the ED50 values (effective concentration inducing 50% killing as measured by Annexin V positivity) were determined. The IC50 values were 0.38 ± 0.07 μM (mean ± SEM), indicating high anti-proliferation effect. The ED50 values ranged from 1.2 to 2.6 μM in 7 cell lines (1.97 ± 0.22 μM) and the remaining cell line (NB4) showed relative resistance to PTC-induced apoptosis (> 10 μM). PTC-209 exhibited dose- and time-dependent anti-proliferative and cytotoxic activities, by inducing G1-S transition delay and apoptosis. PTC-209 induced conformational change of BAX (i.e., BAX activation), loss of mitochondrial membrane potential (MMP), caspase-3 activation and DNA fragmentation in addition to phosphatidylserine (PS) externalization, indicating mitochondrial apoptosis. PTC-209 induced Annexin V in primary AML cells (23.4 ± 4.6% after 48-hour treatment with 1 μM PTC-209, n = 23) in a dose-dependent manner, which is more prominent in immature CD34+CD38- population (33.7 ± 6.0%; P = 0.0036). In accordance with its high anti-leukemia activity, PTC-209 strongly reduced cellular BMI-1 levels in CD34+CD38- AML cells. Higher reduction of BMI-1 expression was positively correlated with higher susceptibility to PTC-209 in CD34+CD38- AML cells (r = 0.88; P = 0.047). The apoptotic activity was observed independent of p53 or FLT3 mutational status of the leukemia cells. Our data suggest that BMI-1 inhibition by small molecule inhibitors may be developed into a novel therapeutic strategy for AML. (Drs M. Andreeff and S. Kimura are co-senior authors with equal contribution to the work) Citation Format: Kensuke Kojima, Yuki Nishida, Aya Maeda, Dhruv Chachad, Hiroaki Kitamura, Jo Ishizawa, Michael Andreeff, Shinya Kimura. BMI-1 inhibition by PTC-209 induces mitochondrial apoptosis in acute myeloid leukemia cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2938. doi:10.1158/1538-7445.AM2015-2938