Clinical impact and characteristics of erythroid dysplasia in adult aplastic anaemia: Results from a multicentre registry.

Morphological dysplasia in haematopoietic cells, defined by a 10% threshold in each lineage, is one of the diagnostic criteria for myelodysplastic neoplasms. Dysplasia limited to the erythroid lineage has also been reported in some cases of aplastic anaemia (AA); however, its significance remains unclear. We herein examined the impact of erythroid dysplasia on immunosuppressive therapy responses and survival in AA patients. The present study included 100 eligible AA patients without ring sideroblasts. Among them, 32 had dysplasia in the erythroid lineage (AA with minimal dysplasia [mini-D]). No significant sex or age differences were observed between AA groups with and without erythroid dysplasia. In severe/very severe AA and non-severe AA patients, a response to anti-thymocyte globulin + ciclosporin within 12 months was observed in 80.0% and 60.0% of AA with mini-D and 42.9% and 90.0% of those without dysplasia, with no significant difference (p = 0.29 and p = 0.24 respectively). Overall survival and leukaemia-free survival did not significantly differ between the groups. Collectively, the present results indicate that the presence of erythroid dysplasia did not significantly affect clinical characteristics or outcomes in AA patients, suggesting that its presence in AA is acceptable. Therefore, erythroid dysplasia should not exclude an AA diagnosis.

[Evaluation of the correlation between JAK2V617F allele burden by Quenching Probe-Tm method and allele-specific quantitative PCR method].

The JAK2V617F mutation is a driver mutation of myeloproliferative neoplasms (MPNs). V617F allele burden is considered a risk factor for complications associated with MPNs and is a predictor of prognosis. In Japan, V617F allele burden has been measured in laboratory settings using the i-densyTM IS-5320 genetic analyzer with the quenching probe-Tm (QP-Tm) method. However, since 2020, allele-specific quantitative PCR (AS-qPCR) is being performed in clinical settings for measuring V617F allele burden. To investigate the clinical usefulness of the QP-Tm method in patients with MPNs, we evaluated the V617F allele burden measured by both the methods. A good correlation was observed between the V617F allele burden determined using QP-Tm and that determined using AS-qPCR (P<0.001, rs=0.952). The median mutant allele burden, as determined using the QP-Tm method, was significantly higher in patients with polycythemia vera than in those with essential thrombocythemia. The results of this study suggested that the QP-Tm method will continue to be useful clinical ancillary test for measuring V617F allele burden.

VLX1570 induces apoptosis through the generation of ROS and induction of ER stress on leukemia cell lines.

A novel proteasome deubiquitinase inhibitor, VLX1570, has been highlighted as a promising therapeutic agent mainly for lymphoid neoplasms and solid tumors. We examined in vitro effects of VLX1570 on eight myeloid and three lymphoid leukemia cell lines. From cell culture studies, 10 out of 11 cell lines except K562 were found to be susceptible to VLX1570 treatment and it inhibited cell growth mainly by apoptosis. Next, to identify the signaling pathways associated with apoptosis, we performed gene expression profiling using HL-60 with or without 50 nmol/L of VLX1570 for 3 hours and demonstrated that VLX1570 induced the genetic pathway involved in "heat shock transcription factor 1 (HSF1) activation", "HSF1 dependent transactivation", and "Regulation of HSF1 mediated heat shock response". VLX1570 increased the amount of high molecular weight polyubiquitinated proteins and the expression of HSP70 as the result of the suppression of ubiquitin proteasome system, the expression of heme oxygenase-1, and the amount of phosphorylation in JNK and p38 associated with the generation of reactive oxygen species (ROS) induced apoptosis and the amount of phosphorylation in eIF2α, inducing the expression of ATF4 and endoplasmic reticulum (ER) stress dependent apoptosis protein, CHOP, and the amount of phosphorylation slightly in IRE1α, leading to increased expression of XBP-1s in leukemia cell lines. In the present study, we demonstrate that VLX1570 induces apoptosis and exerts a potential anti-leukemic effect through the generation of ROS and induction of ER stress in leukemia cell lines.

Efficacy of the novel tubulin polymerization inhibitor PTC-028 for myelodysplastic syndrome.

Monomer tubulin polymerize into microtubules, which are highly dynamic and play a critical role in mitosis. Therefore, microtubule dynamics are an important target for anticancer drugs. The inhibition of tubulin polymerization or depolymerization was previously targeted and exhibited efficacy against solid tumors. The novel small molecule PTC596 directly binds tubulin, inhibits microtubule polymerization, downregulates MCL-1, and induces p53-independent apoptosis in acute myeloid leukemia cells. We herein investigated the efficacy of PTC-028, a structural analog of PTC596, for myelodysplastic syndrome (MDS). PTC-028 suppressed growth and induced apoptosis in MDS cell lines. The efficacy of PTC028 in primary MDS samples was confirmed using cell proliferation assays. PTC-028 synergized with hypomethylating agents, such as decitabine and azacitidine, to inhibit growth and induce apoptosis in MDS cells. Mechanistically, a treatment with PTC-028 induced G2/M arrest followed by apoptotic cell death. We also assessed the efficacy of PTC-028 in a xenograft mouse model of MDS using the MDS cell line, MDS-L, and the AkaBLI bioluminescence imaging system, which is composed of AkaLumine-HCl and Akaluc. PTC-028 prolonged the survival of mice in xenograft models. The present results suggest a chemotherapeutic strategy for MDS through the disruption of microtubule dynamics in combination with DNA hypomethylating agents.

[Concurrent CALR and SF3B1 gene mutations in a patient with myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis].

A 83-year-old female patient was admitted to our hospital due to hematological manifestation of juvenile granulocytes and macrocytic anemia. Bone marrow (BM) examination revealed erythroid dysplasia and cytoplasmic blasts, and hence the patient was diagnosed with myelodysplastic syndrome with ring sideroblasts and with single lineage dysplasia (MDS-RS-SLD). Erythrocyte transfusion was performed as a supportive therapy, and there was a gradual increase in the number of blood cells. Therefore, BM re-examination was performed and it was confirmed that the number of megakaryocytes increased, so the patient's condition was determined as myelodysplastic/myeloproliferative neoplasms with ring sideroblasts and thrombocytosis (MDS/MPN with RS-T). Incidentally, gene mutation analysis showed CALR gene mutation. Thereafter, administration of hydroxycarbamide and anagrelide did not show adverse events and complications, and a good blood count control was obtained. Furthermore, it was also confirmed that an SF3B1 gene mutation is highly positive in MDS-RS. There was no report on CALR-mutant MDS/MPN in Japan, and it is a rare disease overseas.

Utility of a Fluorescence Microscopy Imaging System for Analyzing the DNA Ploidy of Pathological Megakaryocytes Including 5q- Syndrome.

To investigate megakaryocyte (MK) DNA ploidy in various hematological diseases, fluorescence microscopy imaging system (FMI) can be used to analyze DNA ploidy with cell morphology at the single-cell level by using specialized image-processing software. Here we compared DNA ploidy obtained by FMI measured with that obtained flow cytometry (FCM). With FMI, we could evaluate the DNA ploidy in long-term preserved bone marrow smear samples after staining. We next analyzed the MK DNA ploidy in 42 bone marrow smear samples including 26 myeloid neoplasm cases, and we compared the DNA ploidy and platelet counts in the patients' peripheral blood; the production of platelets was significantly high compared to DNA ploidy in the myeloproliferative neoplasms group. The FMI method revealed that the patients with 5q- syndrome exhibited relatively low DNA ploidy despite high platelet counts, and this result suggested that increased DNA ploidy is not indispensable to abundant platelet production. The FMI method for DNA ploidy will be a useful tool to clarify the relationship between DNA ploidy and platelet production by MKs.

A nationwide survey of hypoplastic myelodysplastic syndrome (a multicenter retrospective study).

Hypoplastic myelodysplastic syndrome (hMDS) is a distinct entity with bone marrow (BM) hypocellularity and the risk of death from BM failure (BMF). To elucidate the characteristics of hMDS, the data of 129 patients diagnosed between April 2003 and March 2012 were collected from 20 institutions and the central review team of the National Research Group on Idiopathic Bone Marrow Failure Syndromes, and compared with 115 non-hMDS patients. More RA and fewer CMMoL and RAEB-t in French-American-British (FAB) and more RCUD and MDS-U and fewer RCMD in World Health Organization (WHO) classifications were found in hMDS than non-hMDS with significant differences. The overall survival (OS) and AML progression-free survival (AML-PFS) of hMDS were higher than those of non-hMDS, especially in patients at age ≥50 and of lower risk in Revised International Prognostic Scoring System (IPSS-R). In competing risks analysis, hMDS exhibited decreased risk of AML-progression in lower IPSS or IPSS-R risk patients, and higher risk of death from BMF in patients at age ≥50. Poor performance status (PS ≥2) and high karyotype risks in IPSS-R (high and very high) were significant risk factors of death and AML-progression in Cox proportional hazards analysis.

Withaferin A suppresses the growth of myelodysplasia and leukemia cell lines by inhibiting cell cycle progression.

Treatment outcomes for acute myeloid leukemia and myelodysplastic syndromes (MDS) remain unsatisfactory despite progress in various types of chemotherapy and hematopoietic stem cell transplantation. Therefore, there is a need for the development of new treatment options. We investigated the growth-suppressive effects of withaferin A (WA), a natural plant steroidal lactone, on myelodysplasia and leukemia cell lines. WA exhibited growth-suppressive effects on the cell lines, MDS-L, HL-60, THP-1, Jurkat and Ramos, and induction of cell cycle arrest at G2/M phase at relatively low doses. Evaluation by annexin V/PI also confirmed the induction of partial apoptosis. Gene expression profiling and subsequent gene set enrichment analysis revealed increased expression of heme oxygenase-1 (HMOX1). HMOX1 is known to induce autophagy during anticancer chemotherapy and is considered to be involved in the treatment resistance. Our study indicated increased HMOX1 protein levels and simultaneous increases in the autophagy-related protein LC3A/B in MDS-L cells treated with WA, suggesting increased autophagy. Combined use of WA with chloroquine, an autophagy inhibitor, enhanced early apoptosis and growth suppression. Together with the knowledge that WA had no apparent suppressive effect on the growth of human normal bone marrow CD34-positive cells in the short-term culture, this drug may have a potential for a novel therapeutic approach to the treatment of leukemia or MDS.

[Research Ethics on Handling of Clinical Samples].

Medical research that has utilized the residual parts of clinical samples after routine laboratory examination has yielded numerous findings and contributed to the progress in clinical medicine as well as the detailed elucidation of pathological states of various diseases. However, ethics guidelines on human medical research have recently been established by the Japanese Government, and the Personal Information Protection Law has now imposed stricter rules. Therefore, the enactment of a new guideline became necessary for the secondary utilization of the residual parts of clinical samples. Basic concepts are proposed as follows: (1) research utilizing the residual parts of clinical samples can be performed using an opt-out form that guarantees the right to refuse'8eing enrolled in a study; and (2) the importance and significance of such studies using residual samples should be disseminated in society. To support the promotion of laboratory medical research and avoid the unnecessary or excessive suppres- sion of research, the Japanese Society of Laboratory Medicine is aiming to devise and disseminate appropriate ethics guidelines. [Review].

[How to Treat the Clinical Specimens for Laboratory Testing in Line with Ethical Guidelines - Chairpersons' Remarks -].

Clinical laboratory studies utilizing residual specimens after laboratory testing have markedly contributed to the development of medical science. However, according to recent rules regarding ethical aspects, the ethical committee of the Japanese Society of Laboratory Medicine (JSLM) developed ethical guidelines for treating residual specimens. In this symposium, several ethical problems concerning the application of such specimens to laboratory investigation were raised and discussed. Concerning whether or not each informed consent should be ob- tained before the secondary use of the residual specimens, this matter itself revealed serious disagreements among institutes. Therefore, the ethical committee of JSLM has to propose uniform and widely acceptable guidelines for the effective utilization of laboratory specimens, aiming at the advancement of laboratory medi- cine. [Review].

[Chairmen's Introductory Remarks -Close Association between Emergency Medical Care and Clinical Examinations -].

Clinical examinations are essential medical elements to determine clinical conditions and make diagnoses, and their utility has also been established in emergency medical care. Furthermore, with the introduction of the 24-hour care system by an increasing number of health care institutions in recent years, the importance of clinical examinations is expected to further increase. Although there has been an increase in laboratory technicians' awareness of emergency medical care and emergency testing in response to this trend, a standardized system has yet to be established to meet de- mands in clinical settings. The primary role of clinical examinations in emergency medical care is to help determine the clinical condi- tions of patients, and they support laboratory technicians in making judgments on the prioritization of exami- nations and their urgency, in addition to the prompt and timely provision of information on examinations re- quired by emergency physicians. In this context, we sincerely hope that this symposium will serve as a signpost to guide clinical examina- tions in the right direction for the future of emergency medical care. [Review].

Rigosertib induces cell death of a myelodysplastic syndrome-derived cell line by DNA damage-induced G2/M arrest.

A multi-kinase inhibitor, rigosertib (ON 01910.Na) has recently been highlighted as a novel type of anti-cancer agent for the treatment of the myelodysplastic syndromes (MDS), but its action mechanisms remain to be clarified. We investigated the in vitro effects of rigosertib on an MDS-derived cell line MDS-L and a myeloid leukemia cell line HL-60. Rigosertib suppressed the proliferation of both HL-60 and MDS-L cells and induced apoptosis by inhibition of the PI3 kinase/Akt pathway. As the effects on cell cycle, rigosertib treatment promoted the phosphorylation of histone H2AX and led to the DNA damage-induced G2/M arrest. In addition, an immunofluorescence staining study demonstrated the abnormal localization of aurora A kinase, suggesting that rigosertib causes perturbation of spindle assembly and deregulated mitotic patterns towards cell cycle arrest and apoptosis. We also found that rigosertib exerted growth inhibitory effects on two lymphoid cell lines, Jurkat and Ramos. We further examined the molecular pathways influenced by rigosertib from the gene expression profiling data of MDS-L cells and found a possible involvement of rigosertib treatment in the upregulation of the genes related to microtubule kinetics and the downregulation of the mRNA degradation system. The gene set enrichment analysis showed the suppression of "nonsense-mediated mRNA decay (NMD)" as the most significantly affected gene set. These data provide a new aspect and a potential utility of rigosertib for the treatment of refractory hematopoietic malignancies.

[Case conference of hematological malignancies based on the morphology of blood cells: chairmen's introductory remarks].

A case conference of hematological malignancies based on the morphology of blood cells was held as a joint symposium of the Japanese Society of Laboratory Medicine and Japanese Society of Laboratory Hematology. Four cases were presented and discussed mainly from the viewpoint of cellular morphology: two cases of acute myeloid leukemia (AML) with myelodysplasia-related changes, one case of adult T-cell leukemia/lymphoma, and one case of chronic myelogenous leukemia in the blast phase. Each case included pathological and morphological findings that were carefully examined and intensively discussed by two experienced commentators and participants. The importance of the morphological evaluation of immature cells such as granular myeloblasts or promyelocytes was reconfirmed at this conference. In addition, immunological, cytogenetic, and molecular examinations were also essential for the final diagnosis of these cases.

Inhibition of TOPORS ubiquitin ligase augments the efficacy of DNA hypomethylating agents through DNMT1 stabilization.

DNA hypomethylating agents (HMAs) are used for the treatment of myeloid malignancies, although their therapeutic effects have been unsatisfactory. Here we show that CRISPR-Cas9 screening reveals that knockout of topoisomerase 1-binding arginine/serine-rich protein (TOPORS), which encodes a ubiquitin/SUMO E3 ligase, augments the efficacy of HMAs on myeloid leukemic cells with little effect on normal hematopoiesis, suggesting that TOPORS is involved in resistance to HMAs. HMAs are incorporated into the DNA and trap DNA methyltransferase-1 (DNMT1) to form DNA-DNMT1 crosslinks, which undergo SUMOylation, followed by proteasomal degradation. Persistent crosslinking is cytotoxic. The TOPORS RING finger domain, which mediates ubiquitination, is responsible for HMA resistance. In TOPORS knockout cells, DNMT1 is stabilized by HMA treatment due to inefficient ubiquitination, resulting in the accumulation of unresolved SUMOylated DNMT1. This indicates that TOPORS ubiquitinates SUMOylated DNMT1, thereby promoting the resolution of DNA-DNMT1 crosslinks. Consistently, the ubiquitination inhibitor, TAK-243, and the SUMOylation inhibitor, TAK-981, show synergistic effects with HMAs through DNMT1 stabilization. Our study provides a novel HMA-based therapeutic strategy that interferes with the resolution of DNA-DNMT1 crosslinks.

Genome-wide identification of human microRNAs located in leukemia-associated genomic alterations.

Cytogenetic alterations, such as amplifications, deletions, or translocations, contribute to myeloid malignancies. MicroRNAs (miRNAs) have emerged as critical regulators of hematopoiesis, and their aberrant expression has been associated with leukemia. Genomic regions containing sequence alterations and fragile sites in cancers are enriched with miRNAs; however, the relevant miRNAs within these regions have not been evaluated on a global basis. Here, we investigated miRNAs relevant to acute myeloid leukemia (AML) by (1) mapping miRNAs within leukemia-associated genomic alterations in human AML cell lines by high-resolution genome arrays and (2) evaluating absolute expression of these miRNAs by massively parallel small RNA sequencing. Seventy-seven percent (542 of 706) of miRNAs mapped to leukemia-associated copy-number alterations in the cell lines; however, only 18% (99 of 542) of these miRNAs are expressed above background levels. As evidence that this subset of miRNAs is relevant to leukemia, we show that loss of 2 miRNAs identified in our analysis, miR-145 and miR-146a, results in leukemia in a mouse model. Small RNA sequencing identified 28 putative novel miRNAs, 18 of which map to leukemia-associated copy-number alterations. This detailed genomic and small RNA analysis points to a subset of miRNAs that may play a role in myeloid malignancies.

[Case conference of hematological diseases based on the morphology of blood cells: Chairman's introductory remarks].

A case conference of hematological diseases based on the morphology of blood cells was held as a Joint Symposium of JSLM and JSLH. Four cases were presented and discussed mainly from the viewpoint of morphology: a case of acute leukemia with basophilia, two cases of acute leukemia and another malignancy, and a case of bone marrow invasion of malignant melanoma. Each case included pathological and curious morphological findings to be carefully examined and intensively discussed by the commentators and participants. Differential diagnosis of immature or abnormal blastic cells was found to be particularly important. Finally, each presenter elucidated the final diagnosis of their own case and added an explanation. The importance of morphological evaluation was reconfirmed at this conference.

Rab27a negatively regulates phagocytosis by prolongation of the actin-coating stage around phagosomes.

Rab27a, a Rab family small GTPase, is involved in the exocytosis of secretory granules in melanocytes and cytotoxic T-cells. Rab27a mutations cause type 2 Griscelli syndrome, which is characterized by immunodeficiency, including uncontrolled macrophage activation known as hemophagocytic syndrome. However, the role of Rab27a in phagocytosis remains elusive. Here, using macrophage-like differentiated HL-60 cells and C3bi-opsonized zymosan as a pathogen-phagocyte model, we show that Rab27a negatively regulates complement-mediated phagocytic activity in association with F-actin remodeling. We found that transfection of Rab27a shRNA into HL-60 cells enhances complement-mediated phagocytosis. To clarify the mechanisms underlying the elevated phagocytosis in Rab27a knockdown cells, we analyzed the process of phagosome formation focusing on F-actin dynamics: F-actin assembly, followed by F-actin extension around the particles and the subsequent degradation of F-actin, leading to internalization of the particles enclosed in phagosomes. Microscopic analysis revealed that these actin-related processes, including F-actin coating and F-actin degradation, proceed more rapidly in Rab27a knockdown cells than in control HL-60 cells. Both elevated phagocytosis and accelerated F-actin remodeling were restored by expression of rescue-Rab27a and Rab27a-Q78L (GTP-bound form), but not by Rab27a-T23N (GDP-bound form). Furthermore, an increased accumulation of Coronin 1A surrounding F-actin coats was observed in Rab27a knockdown cells, suggesting that the function of Coronin 1A is related to the regulation of the F-actin coating. Our findings demonstrate that Rab27a plays a direct regulatory role in the nascent process of phagocytosis by prolongation of the stage of actin coating via suppression of Coronin 1A. This study may contribute to an explanation of the underlying mechanisms of excessive phagocytosis observed in Griscelli syndrome.

Phase I/II study of decitabine in patients with myelodysplastic syndrome: a multi-center study in Japan.

The management of myelodysplastic syndrome (MDS) remains challenging. We performed a phase I/II study to evaluate the safety and efficacy of decitabine in patients with MDS in Japan. Patients with MDS with red cell transfusion dependence or 5-30% blasts in marrow and with an International Prognostic Scoring System score of intermediate-1 or higher were eligible. Patients received intravenous decitabine at 15 or 20 mg/m(2) daily for 5 days every 4 weeks. A total of 37 patients were enrolled. Three patients received 15 mg/m(2) and experienced no dose limiting toxicity during the first cycle. Thirty-four patients received 20 mg/m(2) . Grade 3 or greater non-hematologic toxicities included cerebral infarction (n = 1), subdural hematoma (n = 1), elevated blood glucose (n = 1), and pulmonary hypertension (n = 1). At 20 mg/m(2) , complete response, partial response, and hematologic improvement were observed in 7 (20.6%), 2 (5.9%), and 7 (20.6%) patients, respectively. Complete cytogenetic response was observed in 30% of evaluable 20 patients. The median number of cycles to clinical response was 4 (range 4-8), and duration of remission was 474+ days (range 294-598+). The 2-year rate of acute myeloid leukemia-free survival was 52%. Correlative studies revealed hypomethylation in multiple genes in peripheral blood cells after treatment. Hypomethylation was generally more profound in CD15 + peripheral blood cells, which reflects myeloid cells, than in peripheral blood mononuclear cells. In summary, decitabine was safe and demonstrated efficacy in Japanese patients with high-risk MDS. This trial was registered at ClinicalTrials.gov (NCT00796003).

Rab27b regulates c-kit expression by controlling the secretion of stem cell factor.

Rab27b, a subfamily of Rab27 small GTPases, was originally identified in platelets. However, the role of Rab27b in megakaryocytic lineage cells remains unknown. Here, using a human megakaryoblastic cell line, CMK, we show that Rab27b negatively regulates c-kit-expression. We found that transfection of shRNA-Rab27b into CMK cells led to specific increase in the amount of the receptor-type tyrosine kinase c-kit. To elucidate the molecular mechanisms by which Rab27b regulates c-kit expression, we analyzed the dynamics of c-kit by the stimulation with its ligand, stem cell factor (SCF). We found that cell surface expression of c-kit was promptly reduced and rapidly degraded in both CMK and Rab27b-knockdown CMK cells. Pretreatment with a lysosome inhibitor bafilomycin suppressed the degradation of c-kit, indicating that c-kit expression is controlled by SCF-induced endolysosomal degradation system. We therefore focused on the potential involvement of SCF in Rab27b-mediated effects on c-kit expression levels. We found that autocrine secretion of SCF was downregulated in Rab27b-knockdown cells as compared with parental CMK cells. These results suggest that Rab27b negatively regulates the cell surface expression of c-kit via secretion of SCF and that ligation of SCF leads to the endolysosomal degradation system of c-kit.