The hepatic niche leads to aggressive natural killer cell leukemia proliferation through the transferrin-transferrin receptor 1 axis.

Aggressive natural killer cell leukemia (ANKL) is a rare lymphoid neoplasm frequently associated with Epstein-Barr virus, with a disastrously poor prognosis. Owing to the lack of samples from patients with ANKL and relevant murine models, comprehensive investigation of its pathogenesis including the tumor microenvironment (TME) has been hindered. Here we established 3 xenograft mice derived from patients with ANKL (PDXs), which enabled extensive analysis of tumor cells and their TME. ANKL cells primarily engrafted and proliferated in the hepatic sinusoid. Hepatic ANKL cells were characterized by an enriched Myc-pathway and proliferated faster than those in other organs. Interactome analyses and in vivo CRISPR-Cas9 analyses revealed transferrin (Tf)-transferrin receptor 1 (TfR1) axis as a potential molecular interaction between the liver and ANKL. ANKL cells were rather vulnerable to iron deprivation. PPMX-T003, a humanized anti-TfR1 monoclonal antibody, showed remarkable therapeutic efficacy in a preclinical setting using ANKL-PDXs. These findings indicate that the liver, a noncanonical hematopoietic organ in adults, serves as a principal niche for ANKL and the inhibition of the Tf-TfR1 axis is a promising therapeutic strategy for ANKL.

Downregulation of miR-26 promotes invasion and metastasis via targeting interleukin-22 in cutaneous T-cell lymphoma.

It has been reported that certain microRNAs (miRNA) are associated with the pathogenesis of lymphoma. We have previously demonstrated that histone deacetylase inhibitors restore tumor-suppressive miRNAs, such as miR-16, miR-29, miR-150, and miR-26, in advanced cutaneous T-cell lymphoma (CTCL). Among these, the function of miR-26 remains unclear. In this study, we aimed to reveal the function of miR-26 in CTCL oncogenesis. First, we confirmed that the miR-26 family was markedly dysregulated in CTCL cell lines and primary samples. In vivo analysis using miR-26a-transduced CTCL cells injected into immunodeficient NOG mice demonstrated the significant prolonged survival of the mice, suggesting that the miRNA had a tumor-suppressive function. We performed gene expression assays and identified 12 candidate miR-26 targets, namely RGS13, FAM71F1, OAF, SNX21, CDH2, PTPLB, IL22, DNAJB5, CASZ1, CACNA1C, MYH10, and CNR1. Among these, IL22 was the most likely candidate target because the IL-22-STAT3-CCL20-CCR6 cascade is associated with tumor invasion and metastasis of advanced CTCL. In vitro analysis of IL22 and IL22RA knockdown and miR-26 transduction demonstrated inhibited CTCL cell migration. In particular, IL22 knockdown induced cell apoptosis. Finally, we conducted in vivo inoculation analysis of mice injected with shIL22-transfected CTCL cells, and found no tumor invasion or metastasis in the inoculated mice, although the control mice showed multiple tumor invasions and metastases. These results, along with our previous data, demonstrated that miR-26 is a tumor suppressor that is associated with tumor invasion and the metastasis of advanced CTCL by regulating the IL-22-STAT3-CCL20 cascade. Therefore, a IL-22-targeting therapy could be a novel therapeutic strategy for advanced CTCL.

Impact of hypoxia on the pathogenesis and therapy resistance in multiple myeloma.

Multiple myeloma (MM) is a refractory plasma cell tumor. In myeloma cells, the transcription factor IRF4, the master regulator of plasma cells, is aberrantly upregulated and plays an essential role in oncogenesis. IRF4 forms a positive feedback loop with MYC, leading to additional tumorigenic properties. In recent years, molecular targeted therapies have contributed to a significant improvement in the prognosis of MM. Nevertheless, almost all patients experience disease progression, which is thought to be a result of treatment resistance induced by various elements of the bone marrow microenvironment. Among these, the hypoxic response, one of the key processes for cellular homeostasis, induces hypoxia-adapted traits such as undifferentiation, altered metabolism, and dissemination, leading to drug resistance. These inductions are caused by ectopic gene expression changes mediated by the activation of hypoxia-inducible factors (HIFs). By contrast, the expression levels of IRF4 and MYC are markedly reduced by hypoxic stress. Notably, an anti-apoptotic capability is usually acquired under both normoxic and hypoxic conditions, but the mechanism is distinct. This fact strongly suggests that myeloma cells may survive by switching their dependent regulatory factors from IRF4 and MYC (normoxic bone marrow region) to HIF (hypoxic bone marrow microenvironment). Therefore, to achieve deep remission, combination therapeutic agents, which are complementarily effective against both IRF4-MYC-dominant and HIF-dominated fractions, may become an important therapeutic strategy for MM.

Hypoxia-inducible hexokinase-2 enhances anti-apoptotic function via activating autophagy in multiple myeloma.

Multiple myeloma (MM) is an incurable hematopoietic neoplasm derived from plasma cells, and existing in the bone marrow. Recent developments in the field of myeloma onco-biology have enabled the use of proteasome inhibitors (PIs) as key drugs for MM. PIs can increase cell sensitivity to endoplasmic reticulum stress, leading to apoptosis of myeloma cells. PI cannot kill all myeloma cells, however; one reason of this might be activation of autophagy via hypoxic stress in the bone marrow microenvironment. Hypoxia-inducible gene(s) that regulate autophagy may be novel therapeutic target(s) for PI-resistant myeloma cells. Here, a hypoxia-inducible glycolytic enzyme hexokinase-2 (HK2) was demonstrated to contribute by autophagy activation to the acquisition of an anti-apoptotic phenotype in myeloma cells. We found that hypoxic stress led to autophagy activation accompanied by HK2 upregulation in myeloma cells. Under hypoxic conditions, HK2 knockdown inhibited glycolysis and impaired autophagy, inducing apoptosis. The cooperative effects of a PI (bortezomib) against immunodeficient mice inoculated with HK2-knocked down myeloma cells were examined and significant tumor reduction was observed. An HK2 inhibitor, 3-bromopyruvate (3-BrPA), also induced apoptosis under hypoxic rather than normoxic conditions. Further examination of the cooperative effects between 3-BrPA and bortezomib on myeloma cells revealed a significant increase in apoptotic myeloma cells. These results strongly suggested that HK2 regulates the activation of autophagy in hypoxic myeloma cells. Cooperative treatment using PI against a dominant fraction, and HK2 inhibitor against a minor fraction, adapted to the bone marrow microenvironment, may lead to deeper remission for refractory MM.

Histone deacetylase inhibitors downregulate CCR4 expression and decrease mogamulizumab efficacy in CCR4-positive mature T-cell lymphomas.

Histone deacetylase inhibitors are promising agents for various T-cell lymphomas, including cutaneous T-cell lymphoma, peripheral T-cell lymphoma, and adult T-cell lymphoma/leukemia. CCR4 is an important therapeutic target molecule because mogamulizumab, an anti-CCR4 antibody, has shown promising efficacy against various T-cell lymphomas. In this study, we examined the in vitro synergistic effects of mogamulizumab and histone deacetylase inhibitors against various T-cell lymphomas. First, we examined the expression of CCR4 mRNA and surface CCR4 in various T-cell lymphoma cell lines and found that it was downregulated upon treatment with vorinostat, a pan-histone deacetylase inhibitor. Next, we used isoform-specific histone deacetylase inhibitors and short-interfering RNA to determine the histone deacetylase isoform involved in the regulation of CCR4, and demonstrated that romidepsin, a class I selective histone deacetylase inhibitor, reduced CCR4 most efficiently. Moreover, among class I histone deacetylases, histone deacetylase 2 knockdown led to a reduction of CCR4 in lymphoma cells, suggesting that CCR4 expression is mainly regulated by histone deacetylase 2. When we examined the CCR4 expression in skin samples from primary cutaneous T-cell lymphoma, obtained from the same patients before and after vorinostat treatment, we found that CCR4 expression was greatly reduced after treatment. Finally, when we conducted an antibody-dependent cell-mediated cytotoxicity assay with mogamulizumab by using various lymphoma cells, we found that the efficacy of mogamulizumab was significantly reduced by pretreatment with vorinostat. Altogether, our results suggest that the primary use of histone deacetylase inhibitors before treatment with mogamulizumab might not be suitable to obtain synergistic effects. Moreover, these results have potential implications for optimal therapeutic sequences in various CCR4-positive T-cell lymphomas.

A distinct subtype of Epstein-Barr virus-positive T/NK-cell lymphoproliferative disorder: adult patients with chronic active Epstein-Barr virus infection-like features.

The characteristics of adult patients with chronic active Epstein-Barr virus infection are poorly recognized, hindering early diagnosis and an improved prognosis. We studied 54 patients with adult-onset chronic active Epstein-Barr virus infection diagnosed between 2005 and 2015. Adult onset was defined as an estimated age of onset of 15 years or older. To characterize the clinical features of these adults, we compared them to those of 75 pediatric cases (estimated age of onset <15 years). We compared the prognosis of adult-onset chronic active Epstein-Barr virus infection with that of patients with nasal-type (n=37) and non-nasal-type (n=45) extranodal NK/T-cell lymphoma. The median estimated age of onset of these lymphomas was 39 years (range, 16-86 years). Compared to patients with pediatric-onset disease, those in whom the chronic active Epstein-Barr virus infection developed in adulthood had a significantly decreased incidence of fever (P=0.005), but greater frequency of skin lesions (P<0.001). Moreover, hypersensitivity to mosquito bites and the occurrence of hydroa vacciniforme were less frequent in patients with adult-onset disease (P<0.001 and P=0.0238, respectively). Thrombocytopenia, high Epstein-Barr virus nuclear antigen antibody titer, and the presence of hemophagocytic syndrome were associated with a poor prognosis (P=0.0087, P=0.0236, and P=0.0149, respectively). Allogeneic hematopoietic stem cell transplantation may improve survival (P=0.0289). Compared to pediatric-onset chronic active Epstein-Barr virus infection and extranodal NK/T-cell lymphoma, adult-onset chronic active Epstein-Barr virus infection had a poorer prognosis (P<0.001 and P=0.0484, respectively). Chronic active Epstein-Barr virus infection can develop in a wide age range, with clinical differences between adult-onset and pediatric-onset disease. Adult-onset chronic active Epstein-Barr virus infection is a disease with a poor prognosis. Further research will be needed.

Hypoxia-inducible microRNA-210 regulates the DIMT1-IRF4 oncogenic axis in multiple myeloma.

Multiple myeloma (MM) is characterized by the accumulation of a population of malignant plasma cells within the bone marrow and its microenvironment. A hypoxic niche is located within the microenvironment, which causes myeloma cells to become quiescent, anti-apoptotic, glycolytic, and immature. Cell heterogeneity may be related to distinct gene expression profiles under hypoxic and normoxic conditions. During hypoxia, myeloma cells acquire these phenotypes by downregulating interferon regulatory factor 4 (IRF4), an essential transcription factor in myeloma oncogenesis. To identify essential microRNAs and their targets regulated under hypoxic conditions, we undertook microRNA and cDNA microarray analyses using hypoxia-exposed primary MM samples and myeloma cell lines. Under hypoxia, only miR-210 was highly upregulated and was accompanied by direct downregulation of an 18S rRNA base methyltransferase, DIMT1. This inverse expression correlation was validated by quantitative RT-PCR for primary MM samples. We further determined that DIMT1 has an oncogenic potential as its knockdown reduced tumorigenicity of myeloma cells through regulation of IRF4 expression. Notably, by analyzing gene expression omnibus datasets in the National Center for Biotechnology Information database, we found that DIMT1 expression increased gradually with MM progression. In summary, by screening for targets of hypoxia-inducible microRNA-210, we identified DIMT1 as a novel diagnostic marker and therapeutic target for all molecular subtypes of MM.

Cytosine-Phosphorothionate-Guanine Oligodeoxynucleotides Exacerbates Hemophagocytosis by Inducing Tumor Necrosis Factor-Alpha Production in Mice after Bone Marrow Transplantation.

Hemophagocytic syndrome (HPS) is frequently associated with hematopoietic stem cell transplantation and is treated with some benefit derived from TNF-α inhibitors. However, the mechanisms of how HPS occurs and how a TNF-α inhibitor exerts some benefit to HPS management have remained unclear. We evaluated the effect of toll-like receptor (TLR) ligands, especially focusing on cytosine-phosphorothionate-guanine oligodeoxynucleotide (CpG), a TLR9 ligand, on HPS in mice that underwent transplantation with syngeneic or allogeneic bone marrow (BM) cells (Syn-BMT, Allo-BMT), or with allogeneic BM cells plus splenocytes to promote graft-versus-host disease (GVHD mice). Hemophagocytosis was a common feature early after all BMT, but it subsided in Syn-BMT and Allo-BMT mice. In GVHD mice, however, hemophagocytosis persisted and was accompanied by upregulated production of IFN-γ but not TNF-α, and it was suppressed by blockade of IFN-γ but not TNF-α. A single injection of the TLR9 ligand CpG promoted HPS in all BMT mice and was lethal in GVHD mice, accompanied by greatly upregulated production of TNF-α, IL-6, and IFN-γ. Blocking of TNF-α, but not IL-6 or IFN-γ, suppressed CpG-induced HPS in all BMT mice and rescued GVHD mice from CpG-induced mortality. Thus, TLR9 signaling mediates TNF-α-driven HPS in BMT mice and is effectively treated through TNF-α inhibition.

MicroRNA-150 inhibits tumor invasion and metastasis by targeting the chemokine receptor CCR6, in advanced cutaneous T-cell lymphoma.

In this study, we show that microRNA-150 (miR-150) is significantly downregulated in advanced cutaneous T-cell lymphoma (CTCL), and that this downregulation is strongly associated with tumor invasion/metastasis. Inoculation of CTCL cell lines into nonobese diabetic/Shi-scid interleukin 2γ (IL-2γ) null mice led to CTCL cell migration to multiple organs; however, prior transfection of the cells with miR-150 substantially reduced the invasion/metastasis by directly downregulating CCR6, a specific receptor for the chemokine CCL20. We also found that IL-22 and its specific receptor subunit, IL22RA1, were aberrantly overexpressed in advanced CTCL, and that production of IL-22 and CCL20 was increased in cultured CTCL cells. IL22RA1 knockdown specifically reduced CCL20 production in CTCL cells, suggesting that IL-22 upregulation may activate the production of CCL20 and its binding to CCR6, thereby enhancing the multidirectional migration potential of CTCL cells. CTCL cells also exhibited nutrition- and CCL20-dependent chemotaxis, which were inhibited by miR-150 transfection or CCR6 knockdown. From these findings, we conclude that, in the presence of continuous CCR6 upregulation accompanied by miR-150 downregulation, IL-22 activation leads to continuous CCL20-CCR6 interaction in CTCL cells and, in turn, autocrine metastasis to distal organs. This suggests miR-150, CCL20, and CCR6 could be key targets for the treatment of advanced CTCL.

microRNA in Malignant Lymphoma.

microRNAs (miRNAs) are noncoding regulatory RNAs usually consisting of 20-24 nucleotides. During the past decade, increases and decreases in miRNA expression have been shown to associate with various types of diseases, including cancer. Over 4500 miRNAs have been identified in humans, and it is known that nearly all human protein-encoding genes can be controlled by miRNAs in both healthy and malignant cells. Detailed genome-wide miRNA expression analysis has been performed in various malignant lymphoma subtypes, and these analyses have led to the discovery of subtype-specific miRNA alterations. In this chapter, I describe several key miRNAs and their targets in distinct malignant lymphoma subsets and their roles in their pathogenesis, studies of which will lead new therapeutic strategies against aggressive lymphomas.

Downregulated expression of miR-155, miR-17, and miR-181b, and upregulated expression of activation-induced cytidine deaminase and interferon-α in PBMCs from patients with SLE.

OBJECTIVE: Recent studies on systemic lupus erythematosus (SLE) revealed that microRNAs (miRNAs or miRs) were involved in its pathogenesis. However, only a limited number of miRNAs have been examined. METHODS: We performed quantitative real-time reverse transcription-polymerase chain reaction analyses of peripheral blood mononuclear cells (PBMCs) obtained from 31 untreated SLE patients and 31 healthy subjects to examine the expression levels of miR-155, miR-17, and miR-181b, as well as those of activation-induced cytidine deaminase (AID) and interferon-α (IFN-α) messenger RNAs (mRNAs). We examined the relationship between miR-181b, AID, and IFN-α with a luciferase reporter assay. RESULTS: The expression levels of miR-155, miR-17, and miR-181b were significantly lower in SLE patients than those in healthy controls, whereas those of AID and IFN-α mRNAs were significantly higher in SLE patients than those in healthy controls. The expression levels of miR-155, miR-17, and miR-181b inversely correlated with those of AID and IFN-α mRNAs in SLE patients. The results of the luciferase reporter assay revealed that miR-181b negatively regulated AID and IFN-α. CONCLUSIONS: The results of the present study demonstrated for the first time that there is a differential expression and inverse correlation between the levels the miR-155, miR-17, and miR-181b and target molecules, AID and IFN-α mRNAs, in PBMCs of untreated SLE patients. These alterations may contribute to the pathogenesis of SLE.

Clonal heterogeneity of lymphoid malignancies correlates with poor prognosis.

Clonal heterogeneity in lymphoid malignancies has been recently reported in adult T-cell lymphoma/leukemia, peripheral T-cell lymphoma, not otherwise specified, and mantle cell lymphoma. Our analysis was extended to other types of lymphoma including marginal zone lymphoma, follicular lymphoma and diffuse large B-cell lymphoma. To determine the presence of clonal heterogeneity, 332 cases were examined using array comparative genomic hybridization analysis. Results showed that incidence of clonal heterogeneity varied from 25% to 69% among different types of lymphoma. Survival analysis revealed that mantle cell lymphoma and diffuse large B-cell lymphoma with clonal heterogeneity showed significantly poorer prognosis, and that clonal heterogeneity was confirmed as an independent predictor of poor prognosis for both types of lymphoma. Interestingly, 8q24.1 (MYC) gain, 9p21.3 (CDKN2A/2B) loss and 17p13 (TP53, ATP1B2, SAT2, SHBG) loss were recurrent genomic lesions among various types of lymphoma with clonal heterogeneity, suggesting at least in part that alterations of these genes may play a role in clonal heterogeneity.

Enucleation of human erythroblasts involves non-muscle myosin IIB.

Mammalian erythroblasts undergo enucleation, a process thought to be similar to cytokinesis. Although an assemblage of actin, non-muscle myosin II, and several other proteins is crucial for proper cytokinesis, the role of non-muscle myosin II in enucleation remains unclear. In this study, we investigated the effect of various cell-division inhibitors on cytokinesis and enucleation. For this purpose, we used human colony-forming unit-erythroid (CFU-E) and mature erythroblasts generated from purified CD34(+) cells as target cells for cytokinesis and enucleation assay, respectively. Here we show that the inhibition of myosin by blebbistatin, an inhibitor of non-muscle myosin II ATPase, blocks both cell division and enucleation, which suggests that non-muscle myosin II plays an essential role not only in cytokinesis but also in enucleation. When the function of non-muscle myosin heavy chain (NMHC) IIA or IIB was inhibited by an exogenous expression of myosin rod fragment, myosin IIA or IIB, each rod fragment blocked the proliferation of CFU-E but only the rod fragment for IIB inhibited the enucleation of mature erythroblasts. These data indicate that NMHC IIB among the isoforms is involved in the enucleation of human erythroblasts.

A limited sampling model to estimate exposure to lenalidomide in multiple myeloma patients.

BACKGROUND: The aim of this study was to develop a model able to predict the area under the lenalidomide plasma concentration-time curve (AUC) in multiple myeloma (MM) patients using a limited sampling strategy. METHODS: Forty-six hospitalized Japanese MM patients (25 men and 21 women) participated in this study. On days 3-10 of lenalidomide therapy, whole-blood samples were collected just before oral lenalidomide administration, and 1, 2, 4, 8, 12, and 24 hours thereafter. Plasma concentrations of lenalidomide were analyzed using liquid chromatography-tandem mass spectrometry. RESULTS: The AUC0-24 predicted from a single lenalidomide plasma concentration measured 8 hours after the administration (C8h) showed the highest correlation with the measured AUC0-24 of lenalidomide (AUC0-24 = 13.0 × C8h + 1305.0; r = 0.832). To enhance the correlation between the predicted and the actual AUC0-24 of lenalidomide, we included information regarding lenalidomide elimination by entering creatinine clearance (CCr) data in the predictive formula of lenalidomide AUC0-24. Predicting the AUC0-24 of lenalidomide using data from 2 time points, C0h and C4h, along with CCr data further strengthened the correlation with the measured AUC0-24 of lenalidomide [AUC0-24 = 37.1 × C0h + 6.4 × C4h - 32.1 × CCr + 3265.6; r = 0.842]. CONCLUSIONS: The AUC0-24 of lenalidomide can be predicted using plasma concentrations measured at only 2 time points, C0h and C4h, in combination with CCr. Our study also suggests that the limited sampling strategy approach might help to identify patients with renal function impairment and who, despite dose adjustments, accumulate the drug, leading to a high AUC.

[Detection for therapeutic targets specifically expressed in myeloma side population cells].

ATP binding membrane transporter such as multi drug resistant protein (MDR1) and breast cancer resistance protein (BCRP) are highly activated in side population (SP) of various normal organs. It has been demonstrated that various primary as well as cancer cell lines also possess SP. Since SP cells have been also known as the cancer initiating cell rich population in various cancers, the population might play a crucial role in the pathogenesis of multiple myeloma. Recent our works demonstrated that G2/M (e.g. CCNB1, CDC2), centrosome (e.g.AURKB, CENP), polycomb (e.g. EPC1, EZH2) and proteasome (e.g. UBE3C, PSMA5) related genes were upregulated in the SP of myeloma cell lines and CD138-positive primary samples. Although myeloma has been known as incurable disease, discovery of new agents such as immunomodulatory drugs (lenalidomide) and proteasome inhibitor (bortezomib) provide improvement of prognosis of the tumor entity. These drugs might be effective to downregulate aforementioned aberrantly upregulated gene products in myeloma SP. Here we show some evidences of use of these drugs for targeting myeloma-SP cells.

Comprehensive analysis of microRNAs modulated by histone deacetylase inhibitors identifies microRNA-7-5p with anti-myeloma effect.

Basic research to expand treatment options for multiple myeloma is greatly needed due to the refractory nature of the disease. Histone deacetylase (HDAC) inhibitors, which are epigenetic regulators, are attractive but have limited applications. MicroRNAs (miRNAs), which are also epigenetic regulators, are important molecules that may lead to future therapeutic breakthroughs. In this study, we comprehensively searched for miRNAs that are altered by HDAC inhibitors in myeloma cells. We identified miR-7-5p (miR-7) as a miRNA downregulated by HDAC inhibitors. Transfection of myeloma cell lines with miR-7 suppressed cell proliferation, induced apoptosis, and enhanced the effects of the HDAC inhibitor panobinostat. Expression of miR-7 was downregulated by c-Myc inhibition, but upregulated by bortezomib. Comprehensive examination of miR-7 targets revealed four candidates: SLC6A9, LRRC59, EXOSC2, and PSME3. Among these, we focused on PSME3, an oncogene involved in proteasome capacity in myeloma cells. PSME3 knockdown increases myeloma cell death and panobinostat sensitivity. In conclusion, miR-7, which is downregulated by HDAC inhibitors, is a tumor suppressor that targets PSME3. This miR-7 downregulation may be involved in HDAC inhibitor resistance. In addition, combinations of anti-myeloma drugs that complement changes in miRNA expression should be considered.

Role of microRNA in the pathogenesis of malignant lymphoma.

MicroRNA (miRNA) are non-coding regulatory RNA usually consisting of 20-24 nucleotides. Over the past decade, increases and decreases in miRNA expression have been shown to associate with various types of disease, including cancer. The first two known miRNA aberrations resulted from altered expression of DLEU2 and C13orf25 in hematological malignancies. DLEU2, which encodes miR-15a and miR-16-1, was discovered from 13q14 deletion in chronic lymphocytic leukemia, while C13orf25, which encodes six mature miRNA (miR-17, miR-18, miR-19a, miR-19b, miR-20a and miR-92a), was identified from 13q31 amplification in aggressive B-cell lymphomas. These miRNA were downregulated or upregulated in accordance with genomic deletion or amplification, which suggests that they contribute to tumorigenesis through altered regulation of target oncogenes or tumor suppressors. Consistent with that idea, miR-15a/16-1 is known to regulate Bcl2 in chronic lymphocytic leukemia, and miR-17-92 regulates the tumor suppressors p21, Pten and Bim in aggressive B-cell lymphomas. Dysregulation of other miRNA, including miR-21, miR-29, miR-150 and miR-155, have also been shown to play crucial roles in the pathogenesis of aggressive transformed, high-grade and refractory lymphomas. Addition of miRNA dysregulation to the original genetic events likely enhances tumorigenicity of malignant lymphoma through activation of one or more signaling pathways.

Effect of itraconazole on the concentrations of tacrolimus and cyclosporine in the blood of patients receiving allogeneic hematopoietic stem cell transplants.

PURPOSE: The purpose of this study was to investigate the interactions of itraconazole (ITCZ) with orally administered calcineurin inhibitors (CNIs) in Japanese allogeneic hematopoietic stem cell transplant (HSCT) recipients. METHODS: Sixteen HSCT patients (8 patients each receiving tacrolimus or cyclosporine) were enrolled. An ITCZ oral solution was administered from day 30 after the initiation of ITCZ administration as a loading dose. Before the co-administration of ITCZ and CNI and 1 week daily thereafter, whole blood ITCZ and CNI (tacrolimus or cyclosporine) concentrations were measured in samples taken just before (C0h) and 2 h (C2h) after CNI administration. RESULTS: The median dose-adjusted C0h values of tacrolimus and cyclosporine on day 7 after the start of ITCZ co-administration were 5.6- and 2.7-fold higher, respectively, than the corresponding values obtained before the initiation of ITCZ treatment. On day 7 after ITCZ treatment, the mean single dosages of tacrolimus and cyclosporine were reduced to 33.7 and 66.5 % of the dosages before ITCZ co-administration, respectively, to adjust the CNI target concentration. Although ITCZ co-administration did not alter the dose-adjusted C0h values of tacrolimus in a patient with a CYP3A5 1/ 1 allele, it did change this value of tacrolimus in patients with CYP3A5 3 alleles. However, in patients receiving cyclosporine, no such tendency was observed. CONCLUSION: The magnitude of the interaction between orally administered tacrolimus and ITCZ was significantly greater than that between cyclosporine and ITCZ. Prospective analysis of the CYP3A5 polymorphism may be important to ensure safe and reliable immunosuppressive therapy with tacrolimus in patients treated with ITCZ.

Safety and efficacy of low-dose liposomal amphotericin B as empirical antifungal therapy for patients with prolonged neutropenia.

BACKGROUND: Liposomal amphotericin B (L-AmB) is recommended as an empirical antifungal treatment for patients at increased risk of fungal infections although renal toxicity remains a clinical problem. We therefore conducted a pilot study to evaluate the safety and efficacy of low-dose L-AmB as an empirical antifungal therapy for patients with prolonged neutropenia. METHODS: High-risk patients with hematological malignancies were eligible to enroll in this study provided they had: exhibited neutropenia for at least 1 week; suffered from high-grade fever for 4 days despite treatment with a broad-spectrum antibacterial; and no identified fever-causing pathogen. Low-dose L-AmB (1 mg/kg) was administrated as empirical antifungal therapy. RESULTS: Sixteen patients were registered and, of these, data from the13 patients who did not receive allogeneic stem cell transplantation were analyzed. The median duration of low-dose L-AmB treatment was 8 days. Hypokalemia was seen in one patient: administration of potassium supplements for 10 days restored potassium levels to the normal range. A two-fold increase in creatinine levels was not found in any patients even those taking concomitant nephrotoxic drugs (e.g., amynoglycoside) during the study. One patient stopped receiving the drug due to an infusion-related adverse event. No patients showed breakthrough fungal infections or died during therapy or within 7 days after the end of the study. Increase in the L-AmB dose was necessary due to persistent fever in three patients who withdrew from the study. The satisfactory response rate for low-dose L-AmB was 69 %. CONCLUSION: This study suggests that low-dose L-AmB may be an effective option as empirical antifungal therapy for high-risk patients with febrile neutropenia.

Hypoxia-induced oxidative stress promotes therapy resistance via upregulation of heme oxygenase-1 in multiple myeloma.

BACKGROUND: Multiple myeloma (MM) is a hematopoietic malignancy for which proteasome inhibitors have become available in recent years. However, many patients develop resistance to these drugs during treatment. Therefore, it is important to elucidate the mechanisms underlying resistance acquisition by proteasome inhibitors. Side population (SP) cells, which have a high drug efflux capacity and hypoxic responses in the microenvironment have both provided important insights into drug resistance in MM; however, little is known about the characteristics of SP cells in hypoxic microenvironments. METHODS: We performed cDNA microarray analysis for SP and non-SP obtained from RPMI-8226 and KMS-11 cell lines cultured for 48 h in normoxic and hypoxic conditions (1% O2 ). Genes specifically upregulated in hypoxic SP were examined. RESULTS: Our comprehensive gene expression analysis identified HMOX1, BACH2, and DUX4 as protein-coding genes that are specifically highly expressed in SP cells under hypoxic conditions. We have shown that HMOX1/heme oxygenase-1 (HMOX1/HO-1) is induced by hypoxia-inducible reactive oxygen species (ROS) and reduces ROS levels. Furthermore, we found that HMOX1 contributes to hypoxia-induced resistance to proteasome inhibitors in vitro and in vivo. Excessive ROS levels synergistically enhance bortezomib sensitivity. In clinical datasets, HMOX1 had a strong and significantly positive correlation with MAFB but not MAF. Interestingly, hypoxic stimulation increased MAFB/MafB expression in myeloma cells; in addition, the knockdown of MAFB under hypoxic conditions suppressed HMOX1 expression. CONCLUSION: These results suggest that the hypoxia-ROS-HMOX1 axis and hypoxia-induced MafB may be important mechanisms of proteasome inhibitor resistance in hypoxic microenvironments.