[RNA splicing dysregulation in hematological malignancies].

Recurrent mutations in genes encoding key splicing factors, SF3B1, SRSF2, U2AF1, and ZRSR2 have been found in a variety of cancers, particularly in hematologic malignancies, including myelodysplastic syndromes, chronic myelomonocytic leukemia, acute myeloid leukemia, and chronic lymphocytic leukemia. Global mis-splicing of mRNAs targeted by aberrant splicing factors partly contributes to leukemogenesis through decrease protein expression of tumor suppressors and epigenetic modifiers, caused by mRNAs degradation of aberrantly spliced. Some of the mis-spliced mRNAs influence intracellular oncogenic pathways and cellular processes through a dysregulated expression of associated proteins, whereas others influence the function of co-mutated genes such as aberrant transcriptional regulators. Spliceosomal disruption is common in many cancers, making spliceosome an appealing therapeutic target. The findings that spliceosomal mutant cells rely on wild-type splicing machinery for survival and that splicing factor mutations occur in a mutually exclusive manner strongly suggest that inhibiting wild-type splicing machinery causes synthetic lethality in cancer cells with these mutations. We discuss the characteristics and oncogenic mechanisms of splicing factor mutations, as well as the development of novel treatment strategies targeting aberrant splicing factors in hematologic malignancies.

Aberrant RNA splicing and therapeutic opportunities in cancers.

There has been accumulating evidence that RNA splicing is frequently dysregulated in a variety of cancers and that hotspot mutations affecting key splicing factors, SF3B1, SRSF2 and U2AF1, are commonly enriched across cancers, strongly suggesting that aberrant RNA splicing is a new class of hallmark that contributes to the initiation and/or maintenance of cancers. In parallel, some studies have demonstrated that cancer cells with global splicing alterations are dependent on the transcriptional products derived from wild-type spliceosome for their survival, which potentially creates a therapeutic vulnerability in cancers with a mutant spliceosome. It has been c. 10 y since the frequent mutations affecting splicing factors were reported in cancers. Based on these surprising findings, there has been a growing interest in targeting altered splicing in the treatment of cancers, which has promoted a wide variety of investigations including genetic, molecular and biological studies addressing how altered splicing promotes oncogenesis and how cancers bearing alterations in splicing can be targeted therapeutically. In this mini-review we present a concise trajectory of what has been elucidated regarding the pathogenesis of cancers with aberrant splicing, as well as the development of therapeutic strategies to target global splicing alterations in cancers.

[Outcomes of primary central nervous system lymphoma patients treated with high-dose methotrexate and rituximab].

Primary central nervous system lymphoma (PCNSL) is a rare, aggressive type of non-Hodgkin lymphoma with a poor prognosis and no defined optimal therapeutic strategies. We retrospectively analyzed the survival of six PCNSL patients who were treated with high-dose methotrexate (HDMTX) -based chemotherapy combined with rituximab. The median age at diagnosis was 71 (range, 54-75) years, and the ECOG performance status was ≥3 in four patients. The histopathological findings revealed that all patients had diffuse large B-cell lymphoma. Objective response was obtained in all patients (five, complete response; one, partial response). Three patients had severe non-hematological toxicities: one had pulmonary thromboembolism, one had sepsis, and one developed acute epididymitis. However, each patient recovered and their symptoms could be managed. The median follow-up was 28.8 (range, 13.4-65.5) months. Five patients were still alive and disease-free, and one patient relapsed 62.2 months after the diagnosis. Therefore, the addition of rituximab to HDMTX may improve outcomes. Further clinical investigation is necessary to establish standardized initial therapies for PCNSL, particularly in elderly patients.

Delayed recovery of serum immunoglobulin G is a poor prognostic marker in patients with follicular lymphoma treated with rituximab maintenance.

Clinical trials involving various treatment schedules for rituximab maintenance have been conducted for patients with follicular lymphoma (FL) and have not confirmed their impact on serum immunoglobulin (sIg) levels until the completion of maintenance. However, the long-term use of rituximab is a concern because of circulating plasma cell-depletion risk, suggesting that the mechanism of change in sIg levels after RM has not been determined. Additionally, the relationship between host humoral immunity and the prognosis of patients with B cell malignancies has not been determined. We retrospectively investigated data from 213 patients with FL from a single institute who achieved at least a partial response with rituximab, cyclophosphamide, vincristine, and prednisolone with or without doxorubicin. Of these, 166 patients underwent RM with a median period of 1.6 years. A significantly delayed recovery of sIgG levels was observed in the maintenance group until 3 years after RM in comparison to the observation group. A multivariate analysis showed that a sIgG level of < 718 mg/dl 1 year after RM was an independent predictor for poor progression-free survival (PFS) (hazard ratio, 2.3; P = 0.04). Therefore, the sIgG levels scarcely recovered and were significantly delayed after RM, leading to shorter PFS in patients with FL.

Myelodysplastic syndrome with myelofibrosis in which azacitidine therapy was effective and cord blood transplantation was carried out.

Myelodysplastic syndrome with myelofibrosis (MDS-F) is a disease with a poor prognosis, and patients with this condition are at an increased risk of engraftment failures after allogeneic hematopoietic stem cell transplantation (SCT). Azacitidine (AZA) is effective in high-risk MDS patients. However, the effects of AZA on MDS-F have not been elucidated. AZA was administered to a 62-year-old male with MDS-F for 7 days at a dose of 75 mg/m2. Hematological improvements were observed after only 1 course of treatment. No suitable donor was found through the Japan Marrow Donor Program; therefore, the patient underwent umbilical cord blood transplant (UCBT). Neutrophil engraftment was observed on day 21 after the transplant procedure. He developed acute graft versus host disease (GVHD) of the skin (stage 3/grade II), but it could be controlled using prednisolone. Chronic GVHD was not observed and he was discharged in good general condition on day 68. While treatment prior to allogeneic SCT of MDS-F has not been established, in the present case, the hematological improvement brought about by AZA likely contributed to the patient's positive response to UCBT.

Activation of type I interferon signaling in the parotid and exorbital lachrymal glands during the acute phase of encephalomyocarditis (EMC) virus infection in mice.

The present study was carried out to clarify the mechanisms of EMC virus-induced sialodacryoadenitis in mice during the acute phase infection focusing on the activation of type I interferon (IFN) signaling in the parotid and exorbital lachrymal glands. In the parotid gland, a few apoptotic acinar cells were detected at 2days post inoculation (DPI). The ratio of apoptotic acinar cells increased at 3 and 4DPI. On the other hand, in the exorbital lachrymal gland, apoptosis of acinar cells and infiltration of inflammatory cells mainly composed of mononuclear cells started at 3DPI, and prominent acinar cell damage developed at 4DPI. Viral RNA was detected at 3 and 4DPI in both glands and the expression level was higher in the exorbital lachrymal gland than in the parotid gland. The up-regulation of IFN-stimulated genes (ISGs), such as Irf7, Pkr and Oas, was quickly induced at 2DPI in the parotid gland, and this probably contributed to suppress viral replication and to eliminate affected cells by apoptosis. In the exorbital lachrymal gland, the expression levels of ISGs mRNAs were not elevated at 2DPI, suggesting no induction of an effective anti-viral response such as apoptosis at this time point. In the exorbital lachrymal gland, the mRNA expression of IFN beta and IFN alpha (type I IFNs) was weak- to strong-positive at 1DPI, and became negative at 2DPI. The weak- to strong-positive expression of IFNs at 1DPI is likely related to the abrupt viral replication and pathological changes in the exorbital lachrymal gland through activating the negative feedback regulation that depressed the IFN signaling cascade at 2DPI. In conclusion, the present study showed the changes in factors involved in the activation of type I IFN signaling cascade in the parotid and exorbital lachrymal glands and their differences between the two glands during the acute phase of EMC virus infection in mice.

Thermo-stable carbon nanotube-TiO2 nanocompsite as electron highways in dye-sensitized solar cell produced by bio-nano-process.

We produced a thermostable TiO2-(anatase)-coated multi-walled-carbon-nanotube (MWNT) nanocomposite for use in dye-sensitized solar cells (DSSCs) using biological supuramolecules as catalysts. We synthesized two different sizes of iron oxide nanoparticles (NPs) and arrayed the NPs on a silicon substrate utilizing two kinds of genetically modified cage-shaped proteins with silicon-binding peptide aptamers on their outer surfaces. Chemical vapor deposition (CVD) with the vapor-liquid-solid phase (VLS) method was applied to the substrate, and thermostable MWNTs with a diameter of 6 ± 1 nm were produced. Using a genetically modified cage-shaped protein with carbon-nanomaterials binding and Ti-mineralizing peptides as a catalyst, we were able to mineralize a titanium compound around the surface of the MWNT. The products were sintered, and thin TiO2-layer-coated MWNTs nanocomoposites were successfully produced. Addition of a 0.2 wt% TiO2-coated MWNT nanocomposite to a DSSC photoelectrode improved current density by 11% and decreased electric resistance by 20% compared to MWNT-free reference DSSCs. These results indicate that a nanoscale TiO2-layer-coated thermostable MWNT structure produced by our mutant proteins works as a superior electron transfer highway within TiO2 photoelectrodes.

Hodgkin Lymphoma-related Inflammatory Modification-displayed Castleman Disease-like Histological Features and Positron Emission Tomography/Computed Tomography Usefulness for the Differential Diagnosis.

Hodgkin lymphoma (HL) and idiopathic multicentric Castleman disease (iMCD) are markedly different conditions. However, in some cases, histological similarities caused by elevated cytokines, including interleukin-6, can lead to a misdiagnosis of HL as Castleman disease (CD). We herein report a patient with HL who had been diagnosed with CD by an expert panel and for whom an additional biopsy was useful for determining the correct diagnosis. Furthermore, we analyzed the positron emission tomography/computed tomography findings at the diagnosis and found that the maximum standardized uptake value was useful for distinguishing HL from iMCD.

Systematic identification of intron retention associated variants from massive publicly available transcriptome sequencing data.

Many disease-associated genomic variants disrupt gene function through abnormal splicing. With the advancement of genomic medicine, identifying disease-associated splicing associated variants has become more important than ever. Most bioinformatics approaches to detect splicing associated variants require both genome and transcriptomic data. However, there are not many datasets where both of them are available. In this study, we develop a methodology to detect genomic variants that cause splicing changes (more specifically, intron retention), using transcriptome sequencing data alone. After evaluating its sensitivity and precision, we apply it to 230,988 transcriptome sequencing data from the publicly available repository and identified 27,049 intron retention associated variants (IRAVs). In addition, by exploring positional relationships with variants registered in existing disease databases, we extract 3,000 putative disease-associated IRAVs, which range from cancer drivers to variants linked with autosomal recessive disorders. The in-silico screening framework demonstrates the possibility of near-automatically acquiring medical knowledge, making the most of massively accumulated publicly available sequencing data. Collections of IRAVs identified in this study are available through IRAVDB ( https://iravdb.io/ ).

Quantitative protein profiling of phenobarbital-induced drug metabolizing enzymes in rat liver by liquid chromatography mass spectrometry using formalin-fixed paraffin-embedded samples.

Administration of a compound can induce drug-metabolizing enzymes (DMEs) in the liver. DME induction can affect various parameters in toxicology studies. Therefore, evaluation of DME induction is important for interpreting test compound-induced biological responses. Several methods such as measurement of hepatic microsomal DME activity using substrates, electron microscopy, or immunohistochemistry have been used; however, these methods are limited in throughput and specificity or are not quantitative. Liquid chromatography mass spectrometry (LC/MS)-based protein analysis can detect and quantify multiple proteins simultaneously per assay. Studies have shown that formalin-fixed paraffin-embedded (FFPE) samples, which are routinely collected in toxicology studies, can be used for LC/MS-based protein analysis. To validate the utility of LC/MS using FFPE samples for quantitative evaluation of DME induction, we treated rats with a DME inducer, phenobarbital, and compared the protein expression levels of 13 phase-I and 11 phase-II DMEs between FFPE and fresh frozen hepatic samples using LC/MS. A good correlation between data from FFPE and frozen samples was obtained after analysis. In FFPE and frozen samples, the expression of 6 phase-I and 8 phase-II DMEs showed a similar significant increase and a prominent rise in Cyp2b2 and Cyp3a1 levels. In addition, LC/MS data were consistent with the measurement of microsomal DME activities. These results suggest that LC/MS-based protein expression analysis using FFPE samples is as effective as that using frozen samples for detecting DME induction.

Impact of Omission/Reduction of Vincristine From R-CHOP in Treatment of DLBCL.

BACKGROUND: The R-CHOP regimen (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) is the standard therapy for patients with diffuse large B-cell lymphoma (DLBCL). However, vincristine is sometimes omitted or reduced owing to side effects. MATERIALS AND METHODS: We retrospectively reviewed newly diagnosed patients with DLBCL with R-CHOP-like chemotherapy in our institute from January 2005 to February 2018 to investigate whether the omission/reduction of vincristine reduced the efficacy of the treatment. We compared the overall survival (OS) with and without the omission/reduction of vincristine from the R-CHOP regimen. RESULTS: A total of 576 cases were reviewed, and vincristine was omitted/reduced in 50 (9%) patients. The 4-year OS with and without vincristine omission/reduction for relative dose intensity < 80%, 50%, and 25% was 70% versus 82% (P = .035), 70% versus 82% (P = .085), and 53% versus 82% (P = .0007). In a multivariate analysis, adjusting for international prognostic index risk factors, a statistically significant, poor OS was indicated in the patients with relative dose intensity < 25%. CONCLUSIONS: Excessive dose omission/reduction of vincristine might lead to a substantial loss of efficacy of R-CHOP therapy.

Pharmacological evaluation of TAK-828F, a novel orally available RORγt inverse agonist, on murine chronic experimental autoimmune encephalomyelitis model.

We investigated the potency of TAK-828F, a RORγt inverse agonist, in murine experimental autoimmune encephalomyelitis (EAE) model. TAK-828F inhibited the differentiation of Th17 and Th1/17 cells in inguinal lymph node. Increase of these cells in central nervous system (CNS) was also inhibited by TAK-828F. Prophylactic and therapeutic treatments of TAK-828F were efficacious in the model. Plasma concentration of TAK-828F was higher than that in CNS. These results indicate that TAK-828F mainly acts at peripheral and results in the reduction of Th17- and Th1/17-dependent inflammation in CNS. Blocking RORγt may be a promising strategy for treatment of multiple sclerosis.

Neurotoxicity of MPTP to migrating neuroblasts: studies in acute and subacute mouse models of Parkinson's disease.

The acute or subacute administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been widely used in C57BL/6 mice to develop models of Parkinson's disease (PD). The loss of dopaminergic neurons is suggested to be mediated by a mechanism of nonapoptotic cell death or by apoptosis. In recent years, the notion that the neurotoxicity of MPTP is restricted to dopaminergic neurons in the substantia nigra (SN) has been challenged. Here, we provide evidence of rapid cell death in the subventricular zone (SVZ) and rostral migratory stream (RMS) in the adult C57BL/6 mouse brain in response to acute or subacute treatment with MPTP. Significant terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) of fragmented DNA was observed at 24 h (or 1 day) after the last injection in the acute model or after the first injection in the subacute model. Ultrastructural analysis confirmed that dying cells displayed an apoptotic morphology. Using a double labeling method, we demonstrated that the phenotype of the cells undergoing apoptosis is that of migrating neuroblasts. This is further supported by evidence of a subsequent loss of migrating neuroblasts. The results raise the possibility that migrating neuroblasts in the SVZ and RMS may be more vulnerable to MPTP than nigrostriatal dopaminergic neurons in the SN, and the death of migrating neuroblasts may be a primary event in the mouse model of PD. Furthermore, our data suggests that the death and subsequent loss of migrating neuroblasts in the acute or subacute model probably lead to a decreased potential for neurogenesis to some extent.

Expression of epidermal growth factor receptor protein in the liver of db/db mice after partial hepatectomy.

Liver regeneration was impaired after partial hepatectomy (PH) in leptin receptor-deficient db/db mice with severe liver steatosis. In the present study, we analyzed the mode of epidermal growth factor receptor (EGFR) protein expression in the liver of 5- and 10-week-old db/db and age-matched control mice. In 5-week-old db/db mice, neither the expression of EGFR protein in the intact liver nor the rate of liver regeneration after PH was significantly different from that in age-matched control mice. However, in 10-week-old db/db mice, the level of EGFR protein expression was very low and liver regeneration was prominently suppressed. Histopathologically, much severer fatty change was observed in the liver of 10-week-old db/db mice than 5-week-old db/db mice. These results suggest that the down-regulation of EGFR protein expression is associated with an impairment of liver regeneration in db/db mice and that the severity of hepatic steatosis plays an indirect role in the impairment of liver regeneration by modifying EGFR expression.

Evidence of apoptosis in the subventricular zone and rostral migratory stream in the MPTP mouse model of Parkinson disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is commonly used to create animal models of Parkinson disease. There is conflicting evidence on the occurrence of apoptosis induced by MPTP in the mouse substantia nigra pars compacta. We demonstrated that a single acute injection of MPTP induced apoptosis in the subventricular zone (SVZ) and rostral migratory stream (RMS) in the adult C57BL/6 mouse brain. The number of TUNEL-positive cells peaked at 24 hours after injection and decreased thereafter, paralleling the change in the number of cleaved caspase-3-positive cells after MPTP injection. Results of immunohistochemistry and ultrastructural analyses indicated that the majority of apoptotic cells in the SVZ and RMS were migrating neuroblasts (type A cells), whereas a few were astrocytes (type B cells). No apoptosis occurred in transit-amplifying progenitors (type C cells). The decrease in A cell numbers was most marked on day 2 and lasted to day 8 after the administration. A rapid and transient phagocytosis of apoptotic cells by microglial cells was demonstrated to parallel the MPTP-induced apoptosis. The present findings provide new insight into the extensive neurotoxicity of MPTP and may be valuable in reevaluating the MPTP mouse model of Parkinson disease.

Cell cycle progression is required for nuclear migration of neural progenitor cells.

In the developing brain, neural progenitor cells in the ventricular zone (VZ) show a typical migration pattern-interkinetic nuclear migration, in which nuclear position within the VZ is correlated with the cell cycle. However, the mechanisms underlying this regulation remain unclear. To clarify whether the cell cycle progression controls nuclear migration of neural progenitor cells, we determined whether chemically induced cell cycle arrest affected nuclear migration patterns in the VZ. Administration of 5-azacytidine (5AzC) or cyclophosphamide (CP) to pregnant mice induced cell cycle arrest in the fetal neural progenitor cells of the telencephalon: 5AzC induced G2/M-phase arrest, and CP induced S-phase arrest. We used 5-bromo-2'-deoxyuridine (BrdU) labeling to determine the position of the cell in the cell cycle and the nuclei within the VZ at the same time. Cells arrested in G2/M-phase stopped migrating in the inner area of the VZ. Cells arrested in S-phase stopped migrating in the outer area. These results indicate that nuclear position within the VZ was correlated with cell cycle phase, even when the cell cycle was disrupted, and that the nuclei of neural progenitor cells can migrate only when their cell cycle is going. Our results suggest that cell cycle regulators might control the machinery of migration through a common regulatory mechanism.

Etoposide induces apoptosis and cell cycle arrest of neuroepithelial cells in a p53-related manner.

We clarified that etoposide (VP-16), a topoisomerase II inhibitor, induced apoptosis in the mouse fetal brain. Apoptotic mechanisms and cell cycle arrest in this system were investigated. Four mg/kg of VP-16 was injected into pregnant mice on day 12 of gestation (GD12). The cell cycle and expression of protein and mRNA of p53 and its transcriptional target genes were examined in the fetal brain. The number of p53- and p21-protein-positive cells peaked at 4 h after treatment (HAT). The expression of p21 mRNA was significantly increased at 4 HAT and 8 HAT. The expression of fas mRNA was significantly increased from 2 to 12 HAT. Significant expression of puma mRNA was observed from 1 HAT to 48 HAT. Flow cytometric analysis revealed that VP-16 induced S-phase accumulation and G2 arrest at 4 and 8 HAT, and VP-16-induced apoptosis was significantly increased from 4 to 24 HAT. In an experiment using BrdU treatment of pregnant mice, the migration of neuroepithelial cells in the fetuses was delayed as compared to the migration of controls, and BrdU-positive signals were observed in some pyknotic cells from 8 to 12 HAT. The present results suggest that VP-16 might induce cell cycle arrest at G2/M phase and apoptosis in a p53-related manner.

Involvement of p53 in 1-beta-D-arabinofuranosylcytosine-induced rat fetal brain lesions.

1-beta-D-Arabinofuranosylcytosine (Ara-C), a cytidine analogue cytotoxic to proliferating cells, has a teratogenic effect in the brain of experimental animals and causes neural cell apoptosis in vitro and in vivo. In the present study, pregnant rats were injected with Ara-C on Day 13 of gestation and the fetal brain was collected from 1 to 48 h after treatment. Histopathological examinations revealed marked induction of apoptotic cell death and decrease of mitosis in neuroepithelial cells in the brain of Ara-C-treated fetus, and these changes were most prominent from 9 to 12 h. Expression of p53 protein, which mediates apoptosis and cell cycle arrest after DNA damage, was elevated remarkably and peaked at 3 h. p21, a cyclin-dependent kinase inhibitor responsible for p53-mediated cell cycle arrest, showed intense overexpression in protein and mRNA levels following the increase of p53 protein. The mRNA expressions of other p53 transcriptional target genes, bax, cyclinG1, and fas, also significantly increased and peaked at around 9 h. In conclusion, prenatal treatment of Ara-C is thought to induce apoptosis and inhibition of cell proliferation mediated by p53 and its target genes in the fetal brain.

Impaired liver regeneration after partial hepatectomy in db/db mice.

Fatty liver is the most common hepatic disorder in humans and supposed to be a cause of poor prognosis after liver transplantation and hepatic resection which could be resulted from impaired liver regeneration. This study was carried out to analyze the process of liver regeneration in db/db mice which show severe steatosis because of abnormal leptin receptor. We performed 70% partial hepatectomy (PH) on db/db mice and normal +m/+m mice, and then sacrificed the animals 1, 2, 3, 5, 7 and 10 days later. The liver samples were weighed and examined histologically or immunohistochemically. As a result, the liver mass restitution was significantly inhibited in db/db mice compared with +m/+m mice. The BrdU labelling index peaked at 2 days after PH in both strains, although the value was lower in db/db mice. After that, interestingly, it decreased to the control level at 5 days in +m/+m mice while the recovery was delayed in db/db mice. Similar sequence was also observed in the PCNA labelling index. In addition, the peak time of the mitosis index was 2 days and 5 days after PH in +m/+m mice and in db/db mice, respectively. Thus, although not significant, the proliferative response of hepatocytes to PH occurred somewhat more transient and sharply in +m/+m mice while it lasted somewhat longer in db/db mice. This suggests that db/db mice may be valuable as one of the animal models for the investigation of the effects of steatosis on the liver regeneration.