miR-17-92 cluster-BTG2 axis regulates B-cell receptor signaling in mantle cell lymphoma.

B-cell receptor (BCR) signaling is critically activated and stable for mantle cell lymphoma (MCL), but the underlying mechanism of the activated BCR signaling pathway is not clear. The pathogenic basis of miR-17-92 cluster remains unclear although the oncogenic microRNA (miRNA) miR-17-92 cluster is highly expressed in patients with MCL. We revealed that miR-17-92 cluster overexpression is partly dependent on SOX11 expression and chromatin acetylation of MIR17HG enhancer regions. Moreover, miR-17-92 cluster regulates not only cell proliferation but BCR signaling activation in MCL cell lines. To comprehensively identify miR-17-92 cluster target genes, we performed pulldown-seq, where target RNA of miRNA was captured using the biotinylated miRNA mimics and magnetic bead-coated streptavidin, and quantified using next-generation sequencing. The pulldown-seq identified novel miRNA target genes, including tumor suppressors such as BTG2 (miR-19b), CDKN2A (miR-17), SYNE1 (miR-20a), TET2 (miR-18, miR-19b, and miR-92a), TNFRSF10A (miR-92a), and TRAF3 (miR-17). Notably, the gene expression profile data of patients with MCL revealed that BTG2 expression was negatively associated with that of BCR signature genes, and low BTG2 expression was associated with poor overall survival. Moreover, BTG2 silencing in MCL cell lines significantly induced BCR signaling overactivation and cell proliferation. Our results suggest an oncogenic role of miR-17-92 cluster-activating BCR signaling throughout BTG2 deregulation in MCL. Furthermore, this may contribute to the prediction of the therapeutic efficacy and improved outcomes of MCL.

The lymphocyte/monocyte ratio predicts the efficacy of isatuximab plus pomalidomide in multiple myeloma patients.

BACKGROUND: Isatuximab, an anti-CD38 antibody, has been widely used in treatments for patients with relapsed/refractory multiple myeloma (MM). Despite its high efficacy, not all patients achieve a lasting therapeutic response with isatuximab. OBJECTIVE: We tried to identify biomarkers to predict the effectiveness of isatuximab by focusing on the host's immune status before treatment. METHODS: We retrospectively analyzed the cases of 134 relapsed/refractory MM patients in the Kansai Myeloma Forum database who had received only a first isatuximab treatment. RESULTS: Among the 134 patients, an isatuximab, pomalidomide and dexamethasone (Isa-PD) regimen, isatuximab, carfilzomib and dexamethasone (Isa-KD) regimen and isatuximab and/or dexamethasone (Isa-D) regimen were used in 112, 15 and 7 patients, respectively. The median age at treatment, number of prior treatment regimens, and progression-free survival (PFS) were 71, 6, and 6.54 months, respectively. Multivariate analysis showed that the PFS under the Isa-PD regimen was longer in patients with higher lymphocyte/monocyte ratio (LMR ≥ 4), fewer prior treatment regimens (< 6), and no use of prior daratumumab treatment. The OS under the Isa-PD regimen was longer in patients with higher white blood cell counts (WBC counts ≥ 3000/µL) and higher LMR. The PFS under the Isa-D regimen was longer in patients with fewer prior treatment regimens in univariate analysis, but no parameters were correlated with PFS/OS under the Isa-KD regimen. CONCLUSION: We found that the patients with higher LMR (≥ 4) could obtain longer PFS and OS under the Isa-PD regimen. Other cohort studies of isatuximab treatment might be necessary to substantiate our results.

Skeletal muscle index impacts the treatment outcome of elderly patients with diffuse large B cell lymphoma.

Sarcopenia is a crucial factor in the physical fitness of elderly individuals. This study investigated the prognostic values of multiple parameters of sarcopenia in association with established prognostic factors in elderly Japanese patients with diffuse large B cell lymphoma (DLBCL). As candidate indicators for sarcopenia, the skeletal muscle index (SMI) (cm2 /m2 ), the psoas muscle index, the erector spinae muscle index, the visceral fat index, the subcutaneous fat index, and the visceral to subcutaneous fat area ratio at the third lumbar level were assessed by computed tomography at their initial diagnosis in 102 patients with DLBCL over 75 years old those were diagnosed and treated in our institute from 2007 to 2020. The primary endpoint was overall survival (OS), and the secondary endpoint was progression-free survival (PFS). The median age of patients analyzed was 80 years at diagnosis. The sex-specific cut-offs for the indices adopted two approaches: (i) the historical cut-off values established in the previous study for healthy Japanese individuals (Hamaguchi Y. J Cachexia Sarcopenia Muscle. 2018), and (ii) each sex-specific lowest quartile in our cohort. As the results, SMI evaluated by the historical cut-off and sex-specific lowest quartile was identified as the most influential independent prognostic factor for both OS and PFS among various parameters for sarcopenia. Furthermore, we developed an elderly sarcopenia prognostic index (ESPI). ESPI, which combines SMI evaluated by the historical cut-off and LDH > ULN, demonstrated statistically significant prognostic impacts on OS and PFS. Moreover, compared to the R-IPI, ESPI showed the ability to identify intermediate-risk groups and indicated a trend toward improved predictive accuracy. Our study revealed that SMI is the most appropriate assessment method for evaluating sarcopenia and the critical prognostic factor in OS and PFS of elderly patients with DLBCL.

Efficacy of elotuzumab for multiple myeloma deteriorates after daratumumab: a multicenter retrospective study.

Elotuzumab-based regimens are sometimes selected for multiple myeloma treatment after daratumumab-based regimens. However, there has been insufficient discussion on the efficacy of elotuzumab after daratumumab. We used Kansai Myeloma Forum registration data in a multicenter retrospective evaluation of the efficacy of elotuzumab after daratumumab. Overall survival (OS) rate and time to next treatment (TTNT) were significantly worse in the cohort given elotuzumab after daratumumab (Dara cohort, n = 47) than in the cohort with no history of daratumumab administration before elotuzumab (No-Dara cohort, n = 80, OS: P = 0.03; TTNT: P = 0.02; best response: P < 0.01). In the Dara cohort, OS and TTNT rates were worse with sequential elotuzumab use after daratumumab than with non-sequential (OS: P = 0.02; TTNT: P = 0.03). In patients given elotuzumab < 180 days after daratumumab, OS (P = 0.08) and best response (P = 0.21) tended to be worse, and TTNT was significantly worse (P = 0.01), than in those given elotuzumab after ≥ 180 days. These findings were confirmed by subgroup analyses and multivariate analyses. Monoclonal-antibody-free treatment might be preferable after daratumumab-based regimens. If possible, elotuzumab-based regimens should be considered only ≥ 180 days after daratumumab use.

Triple targeting of RSK, AKT, and S6K as pivotal downstream effectors of PDPK1 by TAS0612 in B-cell lymphomas.

B-cell lymphomas (BCLs) are the most common disease entity among hematological malignancies and have various genetically and molecularly distinct subtypes. In this study, we revealed that the blockade of phosphoinositide-dependent kinase-1 (PDPK1), the master kinase of AGC kinases, induces a growth inhibition via cell cycle arrest and the induction of apoptosis in all eight BCL-derived cell lines examined, including those from activated B-cell-like diffuse large B-cell lymphoma (DLBCL), double expressor DLBCL, Burkitt lymphoma, and follicular lymphoma. We also demonstrated that, in these cell lines, RSK2, AKT, and S6K, but not PLK1, SGK, or PKC, are the major downstream therapeutic target molecules of PDPK1 and that RSK2 plays a central role and AKT and S6K play subsidiary functional roles as the downstream effectors of PDPK1 in cell survival and proliferation. Following these results, we confirmed the antilymphoma efficacy of TAS0612, a triple inhibitor for total RSK, including RSK2, AKT, and S6K, not only in these cell lines, regardless of disease subtypes, but also in all 25 patient-derived B lymphoma cells of various disease subtypes. At the molecular level, TAS0612 caused significant downregulation of MYC and mTOR target genes while inducing the tumor suppressor TP53INP1 protein in these cell lines. These results prove that the simultaneous blockade of RSK2, AKT, and S6K, which are the pivotal downstream substrates of PDPK1, is a novel therapeutic target for the various disease subtypes of BCLs and line up TAS0612 as an attractive candidate agent for BCLs for future clinical development.

Tumour-derived exosomes promote the induction of monocytic myeloid-derived suppressor cells from peripheral blood mononuclear cells by delivering miR-106a-5p and miR-146a-5p in multiple myeloma.

The shift of the tumour immune microenvironment to a suppressive state promotes not only the development and progression of the disease in multiple myeloma (MM) but also the development of resistance to immunotherapy. We previously demonstrated that myeloma cells can induce monocytic myeloid-derived suppressor cells (M-MDSCs) from healthy peripheral blood mononuclear cells (PBMCs) via the concomitant secretion of CC motif chemokine ligand 5 (CCL5) and macrophage migration inhibitory factor (MIF), but an unknown mediator also promotes M-MDSC induction. This study demonstrates that miR-106a-5p and miR-146a-5p delivered by tumour-derived exosomes (TEXs) from myeloma cells play essential roles in M-MDSC induction in MM. MiR-106a-5p and miR-146a-5p upregulate various immunosuppressive/inflammatory molecules in PBMCs, such as IDO1, CD38, programmed death-ligand 1, CCL5 or MYD88, which are involved in interferon (IFN)-α response, IFN-γ response, inflammatory response, tumour necrosis factor-α signalling and Interleukin-6-JAK-STAT3 signalling. These molecular features mirror the increases in myeloid cellular compartments of PBMCs when co-cultured with myeloma cells. MiR-106a-5p and miR-146a-5p have a compensatory relationship, and these two miRNAs collaborate with CCL5 and MIF to promote M-MDSC induction. Collectively, novel therapeutic candidates may be involved in TEX-mediated sequential cellular and molecular events underlying M-MDSC induction, potentially improving the efficacy of immunotherapy.

Risk factors for CAR-T cell manufacturing failure among DLBCL patients: A nationwide survey in Japan.

For successful chimeric antigen receptor T (CAR-T) cell therapy, CAR-T cells must be manufactured without failure caused by suboptimal expansion. In order to determine risk factors for CAR-T cell manufacturing failure, we performed a nationwide cohort study in Japan and analysed patients with diffuse large B-cell lymphoma (DLBCL) who underwent tisagenlecleucel production. We compared clinical factors between 30 cases that failed (7.4%) with those that succeeded (n = 378). Among the failures, the proportion of patients previously treated with bendamustine (43.3% vs. 14.8%; p < 0.001) was significantly higher, and their platelet counts (12.0 vs. 17.0 × 104 /µL; p = 0.01) and CD4/CD8 T-cell ratio (0.30 vs. 0.56; p < 0.01) in peripheral blood at apheresis were significantly lower than in the successful group. Multivariate analysis revealed that repeated bendamustine use with short washout periods prior to apheresis (odds ratio [OR], 5.52; p = 0.013 for ≥6 cycles with washout period of 3-24 months; OR, 57.09; p = 0.005 for ≥3 cycles with washout period of <3 months), low platelet counts (OR, 0.495 per 105 /µL; p = 0.022) or low CD4/CD8 ratios (

Imaging flow cytometry-based multiplex FISH for three IGH translocations in multiple myeloma.

Three types of chromosomal translocations, t(4;14)(p16;q32), t(14;16)(q32;q23), and t(11;14)(q13;q32), are associated with prognosis and the decision making of therapeutic strategy for multiple myeloma (MM). In this study, we developed a new diagnostic modality of the multiplex FISH in immunophenotyped cells in suspension (Immunophenotyped-Suspension-Multiplex (ISM)-FISH). For the ISM-FISH, we first subject cells in suspension to the immunostaining by anti-CD138 antibody and, then, to the hybridization with four different FISH probes for genes of IGH, FGFR3, MAF, and CCND1 tagged by different fluorescence in suspension. Then, cells are analyzed by the imaging flow cytometry MI-1000 combined with the FISH spot counting tool. By this system of the ISM-FISH, we can simultaneously examine the three chromosomal translocations, i.e, t(4;14), t(14;16), and t(11;14), in CD138-positive tumor cells in more than 2.5 × 104 nucleated cells with the sensitivity at least up to 1%, possibly up to 0.1%. The experiments on bone marrow nucleated cells (BMNCs) from 70 patients with MM or monoclonal gammopathy of undetermined significance demonstrated the promising qualitative diagnostic ability in detecting t(11;14), t(4;14), and t(14;16) of our ISM-FISH, which was more sensitive compared with standard double-color (DC) FISH examining 200 interphase cells with its best sensitivity up to 1.0%. Moreover, the ISM-FISH showed a positive concordance of 96.6% and negative concordance of 98.8% with standard DC-FISH examining 1000 interphase cells. In conclusion, the ISM-FISH is a rapid and reliable diagnostic tool for the simultaneous examination of three critically important IGH translocations, which may promote risk-adapted individualized therapy in MM.

Identification of non-neutralizing anti-factor X autoantibodies in three Japanese cases of autoimmune acquired factor X deficiency.

INTRODUCTION: Autoimmune factor X (FX or F10) deficiency (AiF10D) is an extremely rare acquired haemorrhagic disorder characterized by a severe reduction in FX activity due to autoantibodies against FX. AIM: Anti-FX autoantibodies were investigated in four patients with suspected AiF10D, and their properties were analysed. METHODS AND RESULTS: Anti-FX auto antibodies in plasma were detected by ELISA with three of four cases. One case of anti-FX autoantibody negativity was later diagnosed as AL-amyloidosis. IgG1 and IgG3 coexisted in all anti-FX autoantibodies of the three patients with AiF10D (cases X1, X2, and X3). Western blot analysis showed that the antibodies were bound to the FX light chain for cases X2 and X3, but the binding was weak for case X1. When the fusion proteins of a secretory luciferase with full-length FX or its γ-carboxylated glutamic acid (Gla) domain were added to the plasma of the three patients, both fusion proteins were immunoprecipitated as antigen-antibody complexes. Contrarily, the latter fusion protein produced in the presence of warfarin demonstrated a decrease in the collection rate, suggesting that their autoantibodies recognized the light chain and regions containing Gla residues. Since all three patients were essentially negative for FX inhibitors, it was concluded that the anti-FX autoantibodies for these cases were predominantly non-neutralizing. The concentration of the FX antigen also significantly reduced in these patients, suggesting that anti-FX autoantibodies promote the clearance of FX. CONCLUSION: Immunological anti-FX autoantibody detection is highly recommended to ensure that AiF10D cases are not overlooked, and to start necessary immunosuppressive therapies.

[Immune suppressive cells in the tumor microenvironment of multiple myeloma].

With the development of immune checkpoint inhibitors in cancer therapy, tumor microenvironments have attracted the attention of many researchers as a critical compartment of immune therapies. Immune suppressive cells such as regulatory T cells, myeloid-derived suppressor cells, and tumor-associated macrophages play important roles in regulating anti-tumor immunity in the bone marrow microenvironment in multiple myeloma, in addition to decreased immunogenicity of tumor cells and increased expression of immune checkpoint molecules. These cells are activated by numerous chemicals released by tumor cells or their surroundings, and they suppress dendritic, tumor-specific cytotoxic T, NK, and NKT cells. Multiple myeloma cells use immunological suppressive effects to escape the patients' immune surveillance system. In the future, we hope a better understanding of these immune suppressive cells leads to further improvements in immune therapies.

The Rationale for the Dual-Targeting Therapy for RSK2 and AKT in Multiple Myeloma.

Multiple myeloma (MM) is characterized by remarkable cytogenetic/molecular heterogeneity among patients and intraclonal diversity even in a single patient. We previously demonstrated that PDPK1, the master kinase of series of AGC kinases, is universally active in MM, and plays pivotal roles in cell proliferation and cell survival of myeloma cells regardless of the profiles of cytogenetic and genetic abnormalities. This study investigated the therapeutic efficacy and mechanism of action of dual blockade of two major PDPK1 substrates, RSK2 and AKT, in MM. The combinatory treatment of BI-D1870, an inhibitor for N-terminal kinase domain (NTKD) of RSK2, and ipatasertib, an inhibitor for AKT, showed the additive to synergistic anti-tumor effect on human MM-derived cell lines (HMCLs) with active RSK2-NTKD and AKT, by enhancing apoptotic induction with BIM and BID activation. Moreover, the dual blockade of RSK2 and AKT exerted robust molecular effects on critical gene sets associated with myeloma pathophysiologies, such as those with MYC, mTOR, STK33, ribosomal biogenesis, or cell-extrinsic stimuli of soluble factors, in HMCLs. These results provide the biological and molecular rationales for the dual-targeting strategy for RSK2 and AKT, which may overcome the therapeutic difficulty due to cytogenetic/molecular heterogeneity in MM.

Plateau is a prognostic factor of lenalidomide therapy for previously treated multiple myeloma.

The plateau phase emerging during the treatment of multiple myeloma (MM) is known to last steadily for a certain period, even without treatment. Therefore, the treatment started at plateau phase is expected to be associated with a better outcome. In this study, this hypothesis was evaluated retrospectively for previously treated MM patients in Kansai Myeloma Forum database who received lenalidomide (LEN) with or without dexamethasone for the first time. Disease stability index (DSI) was defined as (maximum - minimum values of M protein during the 90 days before the start of LEN) divided by M-protein values at the start of LEN. The patients were classified into three groups: stable (S), DSI ≤ 0.25; increasing (I), DSI > 0.25 with increasing M protein; decreasing (D), DSI > 0.25 with decreasing M protein. In univariate analysis of 352 patients, DSI group "I", non-IgG type, serum albumin<3.5 g/dL, and age≥70 were statistically significant prognostic factors for both progression-free survival and overall survival. In multivariate analysis, the former 3 risk factors were statistically significant for poor overall survival. Thus, DSI is an independent prognostic factor for the treatment with LEN for previously treated MM.

Outcomes of ixazomib/lenalidomide/dexamethasone for multiple myeloma: A multicenter retrospective analysis.

OBJECTIVES: This study aimed to investigate real-world data of ixazomib plus lenalidomide and dexamethasone (IRd) therapy for patients with relapsed and refractory multiple myeloma (RRMM). METHODS: We retrospectively analyzed 122 patients treated with IRd at 16 centers from May 2017 to January 2019 by using the Kansai Myeloma Forum database. RESULT: At the start of IRd, the median age was 72 years, 66.7% of patients had IgG type, and the median number of prior therapies was 4, comprising bortezomib (85.4%) and lenalidomide (89.3%)-based regimens. Disease progression and adverse events accounted for treatment discontinuation in 46 and 32 patients, respectively. The median overall survival (OS) was not reached, and the median progression-free survival (PFS) was 11.9 months. Sensitivity to bortezomib did not affect the PFS, whereas lenalidomide-refractory patients had significantly lower PFS than lenalidomide-sensitive patients, who were comparable to TOURMALINE-MM1 study. The patients with IgG type had significantly better PFS and OS than those with non-IgG type. CONCLUSION: This study presents the largest real-world data of patients treated with IRd in Asia. However, in real clinical practice, the patient background is different from the TOURMALINE-MM1 study, and IRd showed poor efficacy, especially in the non-IgG type and lenalidomide-refractory patients with RRMM.

Mantle cell lymphoma with EBV-positive Hodgkin and Reed-Sternberg-like cells in a patient after autologous PBSCT: Phenotypically distinct but genetically related tumors.

The case of 70-year-old man with mantle cell lymphoma (MCL) carrying t(11;14) translocation that relapsed as nodal lymphoma combining MCL and classic Hodgkin lymphoma (cHL) 9 years after autologous peripheral blood stem cell transplant (auto-PBSCT) is reported. Lymph nodes contained two separate areas of MCL and cHL-like components. Hodgkin and Reed-Sternberg (HRS)-like cells were accompanied by a prominent histiocyte background. HRS-like cells were CD5- , CD15+ , CD20- , CD30+ , PAX5+ , Bob.1- , Oct2- and EBER+ . The MCL component expressed cyclin D1 and SOX11, whereas cyclin D1 and SOX11 expressions were reduced and lost, respectively, in HRS-like cells. Polymerase chain reaction results showed a single clonal rearrangement of the IGH gene in MCL and cHL-like components. CCND1 break apart fluorescence in situ hybridization showed split signals in both MCL and HRS-like cells, suggesting that MCL and cHL-like components were clonally related. Acquisition of p53 expression and Epstein-Barr virus (EBV)-positivity was seen in HRS-like cells. The patient died of disease progression with elevated hepatobiliary enzymes. The autopsy showed both MCL and cHL-like components around the bile ducts, splenic white pulp and bone marrow. The two components were phenotypically distinct, but genetically related, suggesting that transformation of MCL to HRS-like cells during the course of MCL in association with EBV infection.

Durable Remission of Chemotherapy-Refractory Myeloid Sarcoma by Azacitidine.

Myeloid sarcoma is a rare disease entity of extramedullary myeloid neoplasm that can occur both as an initial isolated myeloid sarcoma without leukemic cell invasion in the peripheral blood and bone marrow, and as the secondary lesion of acute and chronic myeloid leukemias, myelodysplastic syndrome and chronic myeloproliferative neoplasms. Due to its rarity and its frequent emergence as the recurrent lesion after intensive systemic therapy, including allogeneic hematopoietic stem cell transplantation, the standard treatment has not been established for myeloid sarcoma. In this report, we presented an 84-year-old female patient with isolated myeloid sarcoma which progressed to myelodysplastic syndrome and systemic myeloid sarcoma despite various types of conventional anti-leukemic chemotherapies. However, the patient got a durable partial response by the monotherapy of azacitidine, a hypomethylating agent. She received thirteen courses of azacitidine therapy without progression. We discuss the possibility that hypomethylating agents are the novel effective and feasible therapeutic options for myeloid sarcoma, even in cases refractory to or relapsed after intensive systemic treatment. We also discuss the possible future development of hypomethylating agent-containing combinatory therapeutic strategy for myeloid sarcoma, given its direct anti-leukemic effect and immunomodulatory effect.

Lenalidomide and pomalidomide potently interfere with induction of myeloid-derived suppressor cells in multiple myeloma.

An increase in immunosuppressive myeloid-derived suppressor cells (MDSCs) is associated with disease progression and treatment resistance in multiple myeloma (MM). We investigated the mechanisms underlying MDSC induction, and sought to discover a strategy for prevention of MDSC induction in MM. Using a transwell co-culture system, four of nine examined human myeloma-derived cell lines (HMCLs) were potent in inducing monocytic (M)-MDSCs from normal peripheral blood mononuclear cells (PBMCs). As the results, we identified that secretion of C-C motif chemokine ligand 5 (CCL5) and macrophage migration inhibitory factor (MIF) by myeloma cells is a prerequisite for induction of MDSCs in MM. The immunomodulatory drug (IMiD) compounds, such as lenalidomide (LEN) and pomalidomide (POM), were identified as potent inhibitors of MDSC induction through bidirectional molecular effects of cereblon (CRBN)-dependent and -independent downregulation of CCL5 and MIF in myeloma cells; and downregulation of C-C motif chemokine receptor 5, a receptor for CCL5, and induction of interferon regulatory factor 8, a critical transcription factor for monocytic differentiation, in PBMCs. In the present study of the molecular mechanisms underlying MDSC induction, we identified a novel effect of LEN and POM of inhibiting MDSC induction via overlapping regulatory effects in myeloma cells and normal PBMCs.

Sequential therapy of four cycles of bortezomib, melphalan, and prednisolone followed by continuous lenalidomide and dexamethasone for transplant-ineligible newly diagnosed multiple myeloma.

The combinations of melphalan, bortezomib, and prednisolone (VMP) and of lenalidomide and dexamethasone (Rd) are standard treatment strategies for transplant-ineligible newly diagnosed multiple myeloma (NDMM). To make the most of these two strategies, we investigated the efficacy and feasibility of first-line treatment with 4 cycles of VMP followed by continuous Rd therapy in a multi-institutional phase 2 study in Japanese patients with transplant-ineligible NDMM. Thirty-six patients of median age 74 years old with NDMM initially received 35-day cycles of VMP: oral melphalan (6 mg/m2) and prednisolone (60 mg/m2) on days 1 to 4 and bortezomib (1.3 mg/m2) on days 1, 8, 15, and 22. After 4 cycles of VMP, treatment was switched to 28-day cycles of Rd, which was continued until disease progression or emergence of an unacceptable adverse event (AE) in 33 patients, while one patient who achieved CR after VMP continued VMP at the physician's discretion. The overall response rates after VMP and after Rd were 66.7% and 86.1%, including CR rates of 5.6% and 36.1%, respectively. In a median follow-up period of 34.3 months, the progression-free survival and overall survival rates at 3 years were 43.2% and 81.3%, respectively. Grade 3-4 hematological AEs included neutropenia (39% with VMP and 24% with Rd) and thrombocytopenia (11% with VMP and 3% with Rd). There was no death due to an AE. In conclusion, sequential therapy with VMP followed by Rd is effective and mostly feasible for transplant-ineligible NDMM. The study is registered as UMIN000034815.

Dual targeting of bromodomain-containing 4 by AZD5153 and BCL2 by AZD4320 against B-cell lymphomas concomitantly overexpressing c-MYC and BCL2.

Despite the recent therapeutic progress, the prognoses of diffuse large B-cell lymphomas (DLBCLs) that concomitantly overexpress c-MYC and BCL2, i.e., double hit lymphoma (DHL) and double expressing lymphoma (DEL), remain poor. This study examined triple targeting of c-MYC, BCL2 and the B-cell receptor (BCR) signaling pathway for DHL and DEL. We first used AZD5153, a novel bivalent inhibitor for bromodomain-containing 4 (BRD4), in DHL- and DEL-derived cell lines, because BRD4 regulates disease type-oriented key molecules for oncogenesis. AZD5153 was more effective than conventional monovalent BRD4 inhibitors, JQ1 and I-BET151, in inhibiting cell proliferation of a DHL-derived cell line and two DEL-derived cell lines, with at least 10-fold lower half growth inhibitory concentrations. AZD5153 caused G1/S cell cycle blockade, while the apoptosis-inducing effect was relatively modest. At the molecular level, AZD5153 was potent in downregulating various molecules for oncogenesis, such as c-MYC, AKT2 and MAP3K; those involved in the BCR signaling pathway, such as CD19, BLNK and CD79B; and those associated with B-cell development, such as IKZF1, IKZF3, PAX5, POU2AF1 and EBF1. In contrast, AZD5153 did not decrease anti-apoptotic BCL2 proteins, and did not activate pro-apoptotic BH3-only proteins, except BAD. To augment cell death induction, we added a novel BH3-mimicking BCL2 inhibitor AZD4320 to AZD5153, and found that these two agents had a mostly synergistic antitumor effect by increasing cells undergoing apoptosis in all three cell lines. These results provide a rationale for dual targeting of BRD4 and BCL2 using AZD5153 and AZD4320 as a therapeutic strategy against DHL and DEL.

Epigenetic repression of miR-375 is the dominant mechanism for constitutive activation of the PDPK1/RPS6KA3 signalling axis in multiple myeloma.

Cytogenetic/molecular heterogeneity is the hallmark of multiple myeloma (MM). However, we recently showed that the serine/threonine kinase PDPK1 and its substrate RPS6KA3 (also termed RSK2) are universally active in MM, and play pivotal roles in myeloma pathophysiology. In this study, we assessed involvement of aberrant miR-375 repression in PDPK1 overexpression in MM. An analysis of plasma cells from 30 pre-malignant monoclonal gammopathies of undetermined significance and 73 MM patients showed a significant decrease in miR-375 expression in patient-derived plasma cells regardless of the clinical stage, compared to normal plasma cells. Introduction of miR-375 reduced PDPK1 expression in human myeloma cell lines (HMCLs), indicating that miR-375 is the dominant regulator of PDPK1 expression. In addition, miR-375 introduction also downregulated IGF1R and JAK2 in HMCLs. CpG islands in the MIR375 promoter were pathologically hypermethylated in all 8 HMCLs examined and in most of 58 patient-derived myeloma cells. Treatment with SGI-110, a hypomethylating agent, and/or trichostatin A, a histone deacetylase inhibitor, increased miR-375 expression, but repressed PDPK1, IGF1R and JAK2 in HMCLs. Collectively, these results show the universal involvement of overlapping epigenetic dysregulation for abnormal miR-375 repression in MM, which is likely to contribute to myelomagenesis and to subsequent myeloma progression by activating oncogenic signalling pathways.