ALBERT

Description: Recently, it has been demonstrated that the proapoptotic protein BIM showed a deletion polymorphism at exon 3 in eastern Asian population, and some CML patients with the BIM deletion polymorphism are resistant to imatinib treatment (Ng et al. Nature Medicine, 2012). More recently, a BIM single nucleotide polymorphism (SNP) at exon 8 (c465C〉T) has also been found in French CML patients and this SNP is associated with not only imatinib resistance but also the presence of BCR-ABL mutations (Mahon et al. ASH abstract, 2012). We aimed to investigate a possible association between such genetic variations of BIM and clinical manifestation in Japanese CML patients who experienced undetectable minimal residual disease (UMRD: so-called CMR4.5). In this study, we newly analyzed BIM SNP (c465C〉T) in 47 CML-UMRD patients with known BIM deletion polymorphism status (Katagiri et al. Br J Haematol, 2013). Twenty normal subjects were used as controls. The frequency of either BIM SNP at exon 8 or BIM deletion polymorphism did not deviate from the normal subjects in the Japanese population (P = 0.7597 and P = 0.2880, respectively). None of the subjects showed both BIM SNP at exon 8 and BIM deletion polymorphism concomitantly. We then compared the clinical features among 3 CML-UMRD groups: patients with BIM SNP, patients with BIM deletion polymorphism, and patients who showed neither BIM SNP nor BIM deletion polymorphism (no genetic variations). The frequency of CML patients who maintained 400 mg imatinib dose until stopping was significantly higher in those without genetic variations than in those with BIM SNP or BIM deletion polymorphism (P = 0.0002). Moreover, the frequency of CML patients who switched to second tyrosine kinase inhibitors (2nd TKIs) was significantly higher in those with BIM SNP or BIM deletion polymorphism than in those without such polymorphisms (P = 0.0055).Number of CML patientsMaintained IM 400 mgChange of imatinib dose2nd TKIs switchingBIM SNP (c465C〉T)11/474/115/112/11BIM deletion polymorphism6/471/63/62/6BIM SNP or deletion polymorphism17/475/178/174/17No BIM genetic variationss30/4725/305/300/30 This is apparently the first study to circumstantiate the BIM genetic variants in Japanese CML patients with UMPD. Although the number of patients is small, our results suggest that CML patients without BIM deletion polymorphism/SNP could be maintained under standard imatinib dose without switching to 2nd TKIs, and thereby, have a possibility to stop TKIs therapy. Disclosures: Ohyashiki: Norvartis KK: Research Funding, Speakers Bureau; Bristol Meyer Squibe KK: Research Funding, Speakers Bureau.

Description: Background: The inhibition of BCR-ABL1 kinase with tyrosine kinase inhibitors (TKIs) has markedly improved the prognosis of chronic myeloid leukemia (CML). Recently, it has been recognized that some CML patients with a complete molecular response (CMR) are able to maintain treatment-free remission (TFR) after discontinuation of TKIs. However, no predictive prognostic factors for successful discontinuation of the treatment have yet been identified. We set out to further clarify the role of predictive biomarkers in molecular relapse and non-relapse after ABL TKI discontinuation. Materials and methods: Patients in sustained CMR (MR 4.5) undergoing TKI therapy were eligible for inclusion in the study. Molecular relapse was defined as loss of major molecular response (MMR) of at least one point. Genomic DNA was obtained from whole blood using a DNA Extractor WB Kit (Wako, Osaka, Japan), and was subjected to polymerase chain reaction (PCR) amplification using primers designed to detect a deletion site (2903 bp) in intron two of the BCL2L11 gene (forward: 5′-AATACCACAGAGGCCCACAG-3′; reverse: 5′-GCCTGAAGGTGCTGAGAAAG-3′) and JumpStart RedAccuTaq LA DNA polymerase (Sigma Aldrich, St. Louis, MO, USA). Results: 32 CML patients (17 men, 15 women, median age 58.4 years) were included in this study (Sokal category; low 24, intermediate 7, high 1). Six patients were treated with IFNα before TKI treatment, and 3 were treated with IFNα after stopping TKI. Median duration from TKI initiation to discontinuation was 79.3 months (range; 22 to 138 months); median duration of CMR before TKI discontinuation was 47.3 months (range; 5 to 97 months). Seven patients showed loss of MMR; 6 relapsed within 6 months and one showed late relapse at 25 months after discontinuation. The cumulative incidence of MMR loss was estimated as 18.8% at 12 months and at 24 months. Fluctuation of BCR-ABL transcript levels below the MMR threshold (〉 two consecutive positive values) was observed in 6.25% of patients at 24 months after ABL TKI discontinuation. Treatment-free remission was estimated as 81.2% at 12 months and at 24 months. The median period of restoration of second CMR was 6.0 months in re-treated patients. No patient died during the follow-up period. TKI-free remission was estimated as 78.1% at 30 months. There was only a significant difference in BCL2L11 (BIM) deletion polymorphism between the patients who maintained and those who lost MMR (p = 0.0253). No significant difference was observed in prior IFNα therapy, time to complete cytogenetic response (CCyR), time to MMR, and time to CMR between relapsing and non-relapsing patients. Conclusion: Our study shows a specific association between BCL2L11 (BIM) deletion polymorphism and clinical outcome after ABL TKI discontinuation in patients with long-lasting molecular undetectable residual disease. BCL2L11 (BIM) deletion polymorphism may predict relapse after ABL TKI discontinuation, which may have an impact on future ABL TKI discontinuation trials. These results further illustrate the importance of single nucleotide polymorphisms in successful long-term treatment of CML. Disclosures Ohyashiki: Bristol-Myers Squibb KK : Research Funding, Speakers Bureau; Novartis KK: Research Funding, Speakers Bureau.

Description: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematological malignancy, characteristic of skin lesions followed by hematopoietic organ dissemination. The cell of origin of which is considered to be precursors of plasmacytoid dendritic cells (pDCs). BPDCN cells show high frequencies of mutations in TET2 and p53; however, the molecular mechanisms underlying the pathogenesis of BPDCN have not yet been elucidated. RUNX2 transcription factor, located on chromosome 6p21, is critical for the differentiation of pDCs and the enhancer of RUNX2 is activated in pDCs. Since translocation (6;8)(p21;q24), which is a rare, but specific anomaly for BPDCN, involves regions adjacent to RUNX2 and MYC, we demonstrate that the pDC-specific RUNX2 super-enhancer activates the expression of RUNX2, which functions as a lineage-survival transcription factor, but also is hijacked to activate expression of MYC via t(6;8) in BPDCN cells, and that RUNX2 and MYC promote the initiation and propagation of BPDCN by generating a novel mouse model. In order to identify the breakpoint of t(6;8)(p21;q24), we first performed fluorescent in situ hybridization and whole genome sequencing of CAL-1 cells, a BPDCN cell line, and identified a fusion point of chromosome translocation between chromosome 8 in 69 kilobases (kb) downstream of MYC and chromosome 6, which was 58 kb centromeric to a long and clustered super-enhancer of RUNX2 (791 kb upstream of RUNX2) defined by chromatin immunoprecipitation sequencing using anti-H3K27ac or anti-BRD4 antibodies. As we observed the enhanced levels of MYC and RUNX2 expression in BPDCN cells in patients and CAL-1 cells, we knocked down expression of MYC or RUNX2 using distinct shRNA vectors in CAL-1 cells. We found that the knockdown of MYC and/or RUNX2 significantly impaired colony formation capacities. By performing microarray analysis, we found that RUNX2 knockdown significantly reduced expression of pDCs-signature genes in CAL-1 cells, accompanied with the enhanced apoptosis in CAL-1 cells, implying that RUNX2 is critical for the survival of BPDCN cells due to expressing pDCs-signature genes. To evaluate the function of RUNX2 super-enhancer, we examined how BRD4 inhibition affected the proliferative capacities of CAL-1 cells in vitro. Indeed, we found that JQ1-treated CAL-1 cells showed significantly lower H3K27ac modification levels at the RUNX2 super-enhancer and significantly decreased levels of MYC and RUNX2 expression, resulting in the impaired colony formation capacities, which were rescued by the ectopic expression of both RUNX2 and MYC. We also genetically deleted the mutant-allele super-enhancer of RUNX2 on der(8) (seRUNX2der8), but not that on chromosome 6, using CRISPR-Cas9 vectors. After establishing single cell clones, all seRUNX2der8-deleted clones showed markedly impaired colony formation capacities accompanied with the reduced expression of MYC. Taken together, the seRUNX2der8 directly activates the expression of MYC to promote the development of BPDCN, which is reversed by the inhibition of BRD4. We finally examined whether the transduction of MYC and RUNX2 was sufficient for the initiation of BPDCN in vivo in the absence of Tet2 and p53. We purified Lineage-Sca-1+c-Kit+ stem/progenitor cells from wild-type and Tet2/p53 double knockout (DKO) mice and infected them with MYC- and RUNX2-retrovirus vectors. After a 9-day culture promoting the differentiation of pDCs, we transplanted transduced cells into recipient mice together with wild-type competitor cells. MYC+RUNX2-DKO mice showed robust leukocytosis, anemia, and thrombocytopenia and died by two months post-transplantation following the expansion of immature leukemic blasts. A FACS analysis showed that these leukemic blasts were CD11b-CD11cmid/+B220+Bst2+, which was consistent with the murine pDCs immunophenotype, and massively infiltrated the spleen and liver tissues. MYC+RUNX2-DKO leukemic cells were transplantable in secondary recipient mice with the same immunophenotype. Thus, the transduction of MYC and RUNX2 is sufficient to initiate the transformation of lethal BPDCN-like disease in mice lacking Tet2 and p53. We are now exploring the molecular mechanism of how MYC and RUNX2 collaborate to initiate the formation of BPDCN by performing RNA-sequencing analysis and transplantation assay of BPDCN-initiating cells. Disclosures Asou: Asahi Kasei Pharma Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; SRL Inc.: Consultancy; Yakult Honsha Co., Ltd.: Speakers Bureau; Kyowa Hakko Kirin Co., Ltd.: Speakers Bureau; Astellas Pharma Inc.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Research Funding. Ohyashiki:Pfizer KK,: Honoraria, Research Funding; MSD,: Honoraria, Research Funding; Kyowakko Kirin KK,: Research Funding; Jansen Pharma KK,: Research Funding; Novartis KK,: Honoraria, Research Funding; Celegene KK,: Honoraria, Research Funding; Takeda Pharmaceutical KK,: Honoraria, Research Funding; Taiho Pharmaceutical KK: Honoraria, Research Funding; Asahikase: Research Funding; Asteras KK,: Research Funding; Nihon-Seiyaku,: Research Funding; Eizai,: Research Funding; Dainippon Sumitomo KK,: Honoraria, Research Funding; Nippon-shinyaku,: Honoraria, Research Funding; Bristol Meyer Squibb KK,: Honoraria, Research Funding; Ono Pharmaceutical KK,: Honoraria, Research Funding; Chugai KK,: Honoraria, Research Funding.

Description: Background: Therapy-related myeloid neoplasm (tMN) is a late complication of cytotoxic chemotherapy and radiotherapy. Because patients with malignant lymphoma (ML) tend to receive various types of chemotherapy, the developmental mechanism of tMN remains unclear.In myelodysplastic syndrome (MDS), clonal hematopoiesis of indeterminate potential (CHIP) has recently been consideredas a disease background,and preleukemic mutations have been detected as CHIP in peripheral blood samples of some patients with tMN before chemotherapy. Nevertheless, the clonal evolution from CHIP-related genetic modifications to tMN remains to be validated by the sequential analysis of bone marrow (BM) samples. Materials and methods: We performed targeted deepsequencing (TDS) using BM samples and ML tissues of five patients with tMN after treatment for ML between 2005 and 2017 to examine the sequentialclonal evolution of tMN. For DNA sequencing with MiSeq, we used the Myeloid Neoplasms Panel with 50 known mutation target genes of hematopoietic diseases. This study was approvedby the Institutional Review Board of Tokyo Medical University (no. 2151). Results : TDS revealed variedclonal evolution patterns in three patients. In patient 1, a small clone having NRAS, SETBP1, and SMC1A mutations was detectedat the diagnosis of diffuse large B-cell lymphoma [DLBCL; variant allele frequency (VAF): 0.07, 0.05, and 0.07, respectively], whereas other clones having TP53 and TET2 mutations emerged as a dominant clone at tMN by clonal sweeping.In patient 2, a clone having RUNX1 and TET2 mutations (VAF: 0.41 and 0.40, respectively) was detected 6 years before the diagnosis of nodular sclerosis classical Hodgkin lymphoma (NSCHL). The clone seemed to acquired NRAS and NF1 mutations at the NSCHL and tMN diagnoses (VAF: 0.31 and 0.38, respectively).This pattern is similar to the clonal evolution of MDS to secondary acute myeloid leukemia. In patient 3, we detected a clone having a DNMT3A mutation as the primary clone at DLBCL diagnosis; however, this clone was not detectedat the tMN diagnosis. Moreover, a clone having a SF3B1 mutation that was detected as a minor clone (VAF, 0.07) at the DLBCL diagnosis seemingly acquired the TP53 mutation and evolved as a dominant clone at tMN.This pattern demonstrates a clonalevolution from CHIP to tMN.We detected no common nonsynonymous mutations with BM mononuclear cells (BMMCs) in ML tissues of patients with tMN, excluding patient 2. The same RUNX1, TET2, and NRAS mutations observed in BMMCs were detectedat the NSCHL diagnosis in patient 2, however we speculated that these mutations were derived from nonmalignant T cells. Conclusion: This study suggests that the primaryclone as CHIP at the ML diagnosis was not always responsible for tMN, and clones that resisted chemotherapy or radiotherapy may have evolved into tMN by several clonal evolution patterns, including clonal sweeping and linear evolution. Disclosures Ohyashiki: Asteras KK,: Research Funding; Celegene KK,: Honoraria, Research Funding; Nihon-Seiyaku,: Research Funding; Novartis KK,: Honoraria, Research Funding; MSD,: Honoraria, Research Funding; Pfizer KK,: Honoraria, Research Funding; Asahikase: Research Funding; Ono Pharmaceutical KK,: Honoraria, Research Funding; Nippon-shinyaku,: Honoraria, Research Funding; Dainippon Sumitomo KK,: Honoraria, Research Funding; Taiho Pharmaceutical KK: Honoraria, Research Funding; Chugai KK,: Honoraria, Research Funding; Jansen Pharma KK,: Research Funding; Bristol Meyer Squibb KK,: Honoraria, Research Funding; Takeda Pharmaceutical KK,: Honoraria, Research Funding; Kyowakko Kirin KK,: Research Funding; Eizai,: Research Funding.

Description: Recent studies have demonstrated that exosomal microRNAs (miRNAs) have the potential of facilitating molecular diagnosis. Currently, little is known about the underlying mechanism behind late-onset acute graft-versus-host disease (LA GVHD). Identifying differentially expressed miRNAs in exosomes should be useful for understanding the role of miRNAs in this disease. This study was established to investigate the relevance of miRNAs in exosomes derived from patients developing LA GVHD after allogeneic hematopoietic stem cell transplantation (HSCT). Plasma samples were collected from patients with LA GVHD (n = 5), non-GVHD (n = 5), and controls (n = 8) for exosomal miRNA expression profiling using a TaqMan low-density array; the results were validated by quantitative reverse transcription polymerase chain reaction (RT-PCR). We analyzed exosomal miRNAs differentially expressed among these three groups. MirTarBase was employed to predict potential target genes of the miRNAs specific for LA GVHD. We detected 55 miRNAs that were differentially expressed with a significant change 〉2.0-fold between LA GVHD and non-GVHD. Of these, we selected the 10 miRNAs (miR-423-5p, miR-19a, miR-142-3p, miR-128, miR-193b, miR-30c, miR-193a, miR-191, miR-125b, and miR-574-3p) with the most significant differential expression. Using quantitative RT-PCR, we further identified that miR-128 was significantly upregulated at the onset of LA GVHD compared with that in normal controls and is a promising diagnostic marker of LA GVHD, with an area under the curve (AUC) value of 0.975. MirTarBase analysis revealed that the predicted target genes of miR-128 are involved in the immune system and inflammation. Increased expression of miR-128 may serve as a novel, noninvasive biomarker for early LA GVHD diagnosis.

Description: Background Current prognostic model for multiple myeloma (MM) is based on International Staging System (ISS) and presence of specific chromosomal abnormalities (CAs), especially by fluorescence in situ hybridization (FISH) analysis. MicroRNAs (miRNAs) play important roles in the development and progression in multiple myeloma (MM). Previously, we have described that plasma miRNA profiling has showed considerably lower plasma miR-92a levels in newly diagnosed MM patients (Yoshizawa et al. Blood Cancer Journal 2(1):e53, 2012). The aim of this study was to investigate the impact of plasma miR-92a levels to CAs and to prognosis in patients with newly diagnosed MM. Patients and methods From April 2004 to December 2012, 60 patients with newly diagnosed symptomatic MM (median age, 66 years; range, 34-93 years) were included in this study. We measured plasma miR-92a values (miR-92a/miR-638) by qRT-PCR. They were divided into high-risk and standard-risk by using FISH and conventional cytogenetic studies: high-risk cytogenetics was defined as translocations t(4;14), t(14;16), or del (17p13) detected by FISH, or del (13q) by Q-banding according to IMWG guidelines. All others, including t(11;14), were defined as standard-risk cytogenetics. We analyzed the clinical relevance of plasma miR-92a levels with respects to CAs. Furthermore we identified miR-92a expression cut points with the most impact on outcome to investigate which of the some disease characteristics and its cut-off value had prognostic influence in MM patients. Results Chromosomal aberrations were noted in 26 (43%) MM patients after diagnosis, including 12 patients with t(4;14), 5 with t(11;14), 3 with t(14;16), 2 with del (17p13), 2 with del (13q), and 1 with t(4;14) and del (17p13), 1 with t(11;14) and del (17p13). Between MM patients with and without high-risk cytogenetics, there were no significant differences in β2-microglobulin and albumin levels (P = 0.994 and 0.85, respectively), ISS staging (P = 0.583), age (P = 0.651), sex (P = 0.585), frequency of CRAB symptoms (hypercalcemia, P = 0.755; renal insufficiency, P = 0.75; anemia, P = 0.375; bone lesion, P= 0.65, respectively). The plasma miR-92a level was significantly lower in the newly diagnosed MM with high-risk groups than in those with standard-risk groups (P = 0.015). Patients with plasma miR-92a levels 〈 0.04 had a significantly shorter progression-free survival (PFS) than patients with plasma miR-92a levels ≥ 0.04 (median PFS: 48 vs 15.8 months, P = 0.011). In addition, some clinical parameters were associated with adverse PFS: high-risk cytogenetics (P = 0.001), high proportions of bone marrow plasma cells (P = 0.043), high levels of serum β2-microglobulin (P = 0.022) and not attaining ≥ very good partial response (VGPR) (P = 0.007). On multivariate analysis, lower miR-92a level was an independent prognostic factor for PFS. Using the same miR-92a cut points, there was a tendency towards significant difference among standard-risk myeloma patients (P = 0.077). Moreover, the combinations of chromosomal aberrations and plasma miR-92a were able to classify newly diagnosed MM patients with three risk groups with different probabilities. Conclusion The plasma miR-92a values vary across high- and standard-risk cytogenetics in newly diagnosed MM patients. We conclude that measurement of plasma miR-92a levels may not only function as novel biomarkers for diagnosis, but may also be helpful for prognostic stratification. Disclosures: Ohyashiki: Janssen Pharmaceutical co.: Research Funding.

Description: Multiple myeloma (MM) is one of the common hematological malignancies and is a uniformly fatal disorder of B cells characterized by accumulation of abnormal plasma cells in the bone marrow.Clinical progression of patients with MM is improved with the proteasome inhibitor (PI) (e.g. bortezomib) and the immunomodulatory drugs (IMiDs) such as thalidomide and lenalidomide. Although PI and IMiDs have considerably changed the treatment paradigm of MM, many patients show disease relapse due to developing into drug resistance of MM cells. Since the prognosis remains poor for patients with refractory disease, the new therapeutic strategies are required to treat against these patients. Sphingosine-1-phosphate (S1P) is a potent bioactive sphingolipid. Two isoforms of sphingosine kinases (SphKs), SK1 and SK2, catalyze the formation of the S1P in mammalian cells. SphKs have also been shown to be up-regulated in the variety of cancer types. SphKs/S1P/S1P receptor (S1PR) axis is involved in multiple biological processes. It has been reported that S1P is involved in cell proliferation, angiogenesis and inflammation. S1P is also involved in cancer progression including cell transformation, oncogenesis and cell survival in hematological malignancies such as multiple myeloma. Therefore, S1P and SphKs may present attractive targets for MM treatment. One of the S1P analog, fingolimod (FTY720), which is an orally active immunomodulatory drug, is developed for the treatment of multiple sclerosis. SKI-I, which is a non-lipid pan-SphK inhibitor and ABC294640, selective inhibitor of SK2, are currently investigated in a pivotal phase 1 clinical trial against solid tumors. In this study, we investigated the efficacy of fingolimod, SKI-I, and ABC294640 by using the MM cell lines, RPMI8226, MM1.S and MM1.R. 72 hours treatment of fingolimod exhibited cell growth inhibition of MM cell lines in a dose dependent manner. Treatment of SKI-I and ABC294640 also exhibited cell growth inhibition in a dose dependent manner. Since S1P is the ligand for a family of five G-protein-coupled receptors with distinct signaling pathways that regulate angiogenesis and chemotaxis, we next evaluated the chemotactic response of human umbilical vein endothelial cells (HUVEC). We found that 4 hours treatment of S1P significantly induced the migration of HUVECs compared to control medium. Treatment of HUVECs with fingolimod inhibited S1P-stimulated chemotaxis in a dose dependent manner. We also found that S1P-induced chemotaxis was abolished by the SKI-I and ABC294640. These results suggest that intracellular SK1 and SK2 may play the important role in S1P induced chemotaxis of HUVEC. We next investigated the S1P concentrations in MM patient by enzyme-linked immune sorbent assay (ELISA), because S1P is a potent tumorigenic growth factor that is likely released from tumor cells. We found that serum concentrations of S1P were significantly higher in patient with MM compared with normal samples. The average S1P levels of MM and normal control are 1503.431 and 1103.38 (p