Keiya Ozawa

Treatment of Myelodysplastic Syndromes with Recombinant Human Granulocyte Colony-Stimulating Factor: A Preliminary Report

PURPOSEnThe expansion of an abnormal hemopoietic stem cell line is responsible for the myelodysplastic syndromes, which are characterized by pancytopenias, often resulting in lethal infections. Cloned granulocyte colony-stimulating factor (G-CSF) was recently shown to enhance the growth and differentiation of normal granulocyte progenitor cells in vitro. The aim of our study was to examine the effects of recombinant human G-CSF in patients with myelodysplastic syndromes.nnnPATIENTS AND METHODSnFour patients with myelodysplastic syndromes and one patient with smoldering acute myelogenous leukemia following the occurrence of a myelodysplastic syndrome received recombinant human G-CSF by intravenous infusion for six days. Patients received different dosage levels (50 to 1,600 micrograms/m2).nnnRESULTSnA response was seen in all patients, with an increase in both immature myeloid cells in the bone marrow and mature granulocytes in the peripheral blood. The dose levels that could stimulate granulocytopoiesis differed among patients.nnnCONCLUSIONnThese results suggest that, at least in some cases of myelodysplastic syndromes, granulocytopenia can be improved by G-CSF, although it still remains to be determined whether the increase in the number of granulocytes is due to the differentiation and maturation of the myelodysplastic clone or restoration of a residual normal clone.

Characterization of stage progression in chronic myeloid leukemia by DNA microarray with purified hematopoietic stem cells.

Chronic myeloid leukemia (CML) is characterized by the clonal expansion of hematopoietic stem cells (HSCs). Without effective treatment, individuals in the indolent, chronic phase (CP) of CML undergo blast crisis (BC), the prognosis for which is poor. It is therefore important to clarify the mechanism underlying stage progression in CML. DNA microarray is a versatile tool for such a purpose. However, simple comparison of bone marrow mononuclear cells from individuals at different disease stages is likely to result in the identification of pseudo-positive genes whose change in expression only reflects the different proportions of leukemic blasts in bone marrow. We have therefore compared with DNA microarray the expression profiles of 3456 genes in the purified HSC-like fractions that had been isolated from 13 CML patients and healthy volunteers. Interestingly, expression of the gene for PIASy, a potential inhibitor of STAT (signal transducer and activator of transcription) proteins, was down-regulated in association with stage progression in CML. Furthermore, forced expression of PIASy has induced apoptosis in a CML cell line. These data suggest that microarray analysis with background-matched samples is an efficient approach to identify molecular events underlying the stage progression in CML.

1α,25-Dihydroxy vitamin D3 (calcitriol) stimulates proliferation of human circulating monocytes in vitro

Previous studies demonstrated that human circulating monocytes can proliferate in vitro when incubated with lectin‐induced factor(s) from lymphocytes [(1985) Biochem. Biophys. Res. Commun., in press]. This study shows that human monocytes were induced to proliferate when incubated with 1α,25‐dihydroxy vitamin D3 (calcitriol) at physiological concentrations. The optimal dose was about 10 nM. Proliferative activity was examined both by measuring the [su3H]thymidine incorporation and by counting cell nuclei. Among other derivatives of vitamin D3, 1α,24 R‐dihydroxyvitamin D3 and 1α,24R,25‐trihydroxyvitamin D3 stimulated mitotic activity of monocytes. Addition of both calcitriol and lectin‐stimulated lymphocyte‐conditioned medium to the monocyte culture had an additional effect on the mitotic activity of monocytes.

Randomized Phase III Study of Lenalidomide Versus Placebo in RBC Transfusion-Dependent Patients With Lower-Risk Non-del(5q) Myelodysplastic Syndromes and Ineligible for or Refractory to Erythropoiesis-Stimulating Agents

PURPOSEnThis international phase III, randomized, placebo-controlled, double-blind study assessed the efficacy and safety of lenalidomide in RBC transfusion-dependent patients with International Prognostic Scoring System lower-risk non-del(5q) myelodysplastic syndromes ineligible for or refractory to erythropoiesis-stimulating agents.nnnPATIENTS AND METHODSnIn total, 239 patients were randomly assigned (2:1) to treatment with lenalidomide (n = 160) or placebo (n = 79) once per day (on 28-day cycles). The primary end point was the rate of RBC transfusion independence (TI) ≥ 8 weeks. Secondary end points were RBC-TI ≥ 24 weeks, duration of RBC-TI, erythroid response, health-related quality of life (HRQoL), and safety.nnnRESULTSnRBC-TI ≥ 8 weeks was achieved in 26.9% and 2.5% of patients in the lenalidomide and placebo groups, respectively (P < .001). Ninety percent of patients achieving RBC-TI responded within 16 weeks of treatment. Median duration of RBC-TI with lenalidomide was 30.9 weeks (95% CI, 20.7 to 59.1). Transfusion reduction of ≥ 4 units packed RBCs, on the basis of a 112-day assessment, was 21.8% in the lenalidomide group and 0% in the placebo group. Higher response rates were observed in patients with lower baseline endogenous erythropoietin ≤ 500 mU/mL (34.0% v 15.5% for > 500 mU/mL). At week 12, mean changes in HRQoL scores from baseline did not differ significantly between treatment groups, which suggests that lenalidomide did not adversely affect HRQoL. Achievement of RBC-TI ≥ 8 weeks was associated with significant improvements in HRQoL (P < .01). The most common treatment-emergent adverse events were neutropenia and thrombocytopenia.nnnCONCLUSIONnLenalidomide yields sustained RBC-TI in 26.9% of RBC transfusion-dependent patients with lower-risk non-del(5q) myelodysplastic syndromes ineligible for or refractory to erythropoiesis-stimulating agents. Response to lenalidomide was associated with improved HRQoL. Treatment-emergent adverse event data were consistent with the known safety profile of lenalidomide.

Gene therapy comes of age

Gene therapy: The power of persistence Nearly 50 years after the concept was first proposed, gene therapy is now considered a promising treatment option for several human diseases. The path to success has been long and tortuous. Serious adverse effects were encountered in early clinical studies, but this fueled basic research that led to safer and more efficient gene transfer vectors. Gene therapy in various forms has produced clinical benefits in patients with blindness, neuromuscular disease, hemophilia, immunodeficiencies, and cancer. Dunbar et al. review the pioneering work that led the gene therapy field to its current state, describe gene-editing technologies that are expected to play a major role in the fields future, and discuss practical challenges in getting these therapies to patients who need them. Science, this issue p. eaan4672 BACKGROUND Nearly five decades ago, visionary scientists hypothesized that genetic modification by exogenous DNA might be an effective treatment for inherited human diseases. This “gene therapy” strategy offered the theoretical advantage that a durable and possibly curative clinical benefit would be achieved by a single treatment. Although the journey from concept to clinical application has been long and tortuous, gene therapy is now bringing new treatment options to multiple fields of medicine. We review critical discoveries leading to the development of successful gene therapies, focusing on direct in vivo administration of viral vectors, adoptive transfer of genetically engineered T cells or hematopoietic stem cells, and emerging genome editing technologies. ADVANCES The development of gene delivery vectors such as replication-defective retro viruses and adeno-associated virus (AAV), coupled with encouraging results in preclinical disease models, led to the initiation of clinical trials in the early 1990s. Unfortunately, these early trials exposed serious therapy-related toxicities, including inflammatory responses to the vectors and malignancies caused by vector-mediated insertional activation of proto-oncogenes. These setbacks fueled more basic research in virology, immunology, cell biology, model development, and target disease, which ultimately led to successful clinical translation of gene therapies in the 2000s. Lentiviral vectors improved efficiency of gene transfer to nondividing cells. In early-phase clinical trials, these safer and more efficient vectors were used for transduction of autologous hematopoietic stem cells, leading to clinical benefit in patients with immunodeficiencies, hemoglobinopathies, and metabolic and storage disorders. T cells engineered to express CD19-specific chimeric antigen receptors were shown to have potent antitumor activity in patients with lymphoid malignancies. In vivo delivery of therapeutic AAV vectors to the retina, liver, and nervous system resulted in clinical improvement in patients with congenital blindness, hemophilia B, and spinal muscular atrophy, respectively. In the United States, Food and Drug Administration (FDA) approvals of the first gene therapy products occurred in 2017, including chimeric antigen receptor (CAR)–T cells to treat B cell malignancies and AAV vectors for in vivo treatment of congenital blindness. Promising clinical trial results in neuromuscular diseases and hemophilia will likely result in additional approvals in the near future. In recent years, genome editing technologies have been developed that are based on engineered or bacterial nucleases. In contrast to viral vectors, which can mediate only gene addition, genome editing approaches offer a precise scalpel for gene addition, gene ablation, and gene “correction.” Genome editing can be performed on cells ex vivo or the editing machinery can be delivered in vivo to effect in situ genome editing. Translation of these technologies to patient care is in its infancy in comparison to viral gene addition therapies, but multiple clinical genome editing trials are expected to open over the next decade. OUTLOOK Building on decades of scientific, clinical, and manufacturing advances, gene therapies have begun to improve the lives of patients with cancer and a variety of inherited genetic diseases. Partnerships with biotechnology and pharmaceutical companies with expertise in manufacturing and scale-up will be required for these therapies to have a broad impact on human disease. Many challenges remain, including understanding and preventing genotoxicity from integrating vectors or off-target genome editing, improving gene transfer or editing efficiency to levels necessary for treatment of many target diseases, preventing immune responses that limit in vivo administration of vectors or genome editing complexes, and overcoming manufacturing and regulatory hurdles. Importantly, a societal consensus must be reached on the ethics of germline genome editing in light of rapid scientific advances that have made this a real, rather than hypothetical, issue. Finally, payers and gene therapy clinicians and companies will need to work together to design and test new payment models to facilitate delivery of expensive but potentially curative therapies to patients in need. The ability of gene therapies to provide durable benefits to human health, exemplified by the scientific advances and clinical successes over the past several years, justifies continued optimism and increasing efforts toward making these therapies part of our standard treatment armamentarium for human disease. Three essential tools for human gene therapy. AAV and lentiviral vectors are the basis of several recently approved gene therapies. Gene editing technologies are in their translational and clinical infancy but are expected to play an increasing role in the field. After almost 30 years of promise tempered by setbacks, gene therapies are rapidly becoming a critical component of the therapeutic armamentarium for a variety of inherited and acquired human diseases. Gene therapies for inherited immune disorders, hemophilia, eye and neurodegenerative disorders, and lymphoid cancers recently progressed to approved drug status in the United States and Europe, or are anticipated to receive approval in the near future. In this Review, we discuss milestones in the development of gene therapies, focusing on direct in vivo administration of viral vectors and adoptive transfer of genetically engineered T cells or hematopoietic stem cells. We also discuss emerging genome editing technologies that should further advance the scope and efficacy of gene therapy approaches.

Bone marrow-derived mesenchymal stem cells (JR-031) for steroid-refractory grade III or IV acute graft-versus-host disease: a phase II/III study

Following a phase I/II study using mesenchymal stem cells (MSCs; JR-031) for steroid-refractory grade II or III acute graft-versus-host disease (aGVHD), a phase II/III study using the cells focused on steroid-refractory grade III or IV aGVHD was conducted. The number of infused MSCs and the number of MSC infusions were the same as the phase I/II study. No additional immunosuppressant was given for steroid-refractory aGVHD during the course of MSC infusions. Twenty-five patients (grade III, 22 patients and grade IV, 3 patients) were enrolled in this study. At 4xa0weeks after the first MSC infusions, six (24xa0%) and nine patients (36xa0%) achieved a complete response (CR) and partial response (PR), respectively. Durable CR by 24xa0weeks, which was the primary end-point, was obtained in 12 of 25 patients (48xa0%). At 52xa0weeks, 12 patients (48xa0%) treated with MSCs only (six patients) and MSCs plus additional treatments (six patients) were alive in CR. The survival was significantly better in patients showing overall response (OR; CR+PR) than in those showing no OR at 4xa0weeks. Adverse effects commonly associated with MSC infusions were not observed. Taken together, our two clinical trials suggest JR-031 to be effective for steroid-refractory aGVHD.

Expression of granulocyte and granulocyte-macrophage colony-stimulating factors by human non-hematopoietic tumor cells

The expression of granulocyte colony-stimulating factor (G-CSF) mRNA was studied in human non-hematopoietic tumors, including 18 cases of lung cancers 10 cases of stomach cancers, three cases of glioblastomas, and one case each of breast phyllode sarcoma, thyroid cancer, and hepatocellular carcinoma. Northern blot analysis detected G-CSF mRNA in two of the lung cancer cases, in one of the glioblastoma cases, and in both the breast phyllode sarcoma and hepatocellular carcinoma cases. Since G-CSF receptors were not detected on the tumor cells by 125I-G-CSF binding assay, G-CSF autocrine loop are probably not involved in the growth of these G-CSF-producing tumors. Interestingly, granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA was concomitantly expressed in most of these G-CSF-producing tumors. No major gene deletions or rearrangements of G-CSF and GM-CSF genes were demonstrated by Southern blot analysis in the tumors expressing G-CSF and GM-CSF mRNAs except for one of the glioblastomas (G3) in which one chromosome 17 allele was deleted. Although the mechanism of the concomitant expression of G-CSF and GM-CSF mRNA is unknown, relatively high frequency of this phenomenon suggests the presence of common transcriptional factors acting on regulatory regions of G-CSF and GM-CSF genomes.

Constitutive Activation of Stat1 and Stat3 in Primary Erythroleukemia Cells

Signal transducers and activators of transcription (Stat) proteins play important roles in the regulation of hematopoiesis as downstream molecules of cytokine signal transduction. Previously, we demonstrated that Stat1 and Stat3 are activated by ery-thropoietin (EPO) in a human EPO-dependent erythroleukemia cell line UT-7/EPO. We report here that Stat1 and Stat3 are constitutively activated in freshly isolated erythroleukemia cells. In addition, EPO promoted cell growth of these cells, accompanied by enhanced activities of Stat1 and Stat3. Furthermore, mutation in the Stat1/Stat3-binding sites of the c-myc gene promoter clearly blocked its promoter activity in EPO-stimulated primary erythroleukemia cells. Thus, Stat1 and Stat3 may support cell growth in part via c-myc gene activation in primary erythroleukemia cells.

DNA replication of parvovirus B 19 in a human erythroid leukemia cell line (JK-1) in vitro

SummaryA major limitation of studies on the parvovirus B 19, a causative agent of transient aplastic crisis, has been the absence of appropriate cell lines permissive for the virus. In the present study, a human erythroid leukemia cell line (JK-1) was shown to support B 19 virus DNA replication in vitro. Forty-eight hours after virus inoculation of JK-1 liquid cell cultures, the average number of B 19 genome copies was estimated at 3,000 per cell by DNA dot blot analysis. The addition of erythropoietin increased B 19 copy number to 10,000 per cell. The presence of replicative forms of the B 19 virus genome was demonstrated by Southern blot analysis. Although persistent infection of B 19 virus was not observed in JK-1 cells, this culture system will be of value in elucidating the molecular basis of the erythroid specificity of parvovirus B 19.

In Vitro Formation of Macrophage- Epithelioid Cells and Multinucleated Giant Cells by 1α,25-Dihydroxyvitamin D3 from Human Circulating Monocytesa

1 alpha,25-Dihydroxyvitamin D3, the active form of vitamin D3, induced maturation of circulating monocytes to form macrophage-epithelioid cells and multinucleated giant cells in vitro. Calcitriol not only promoted the differentiation of monocytes, as shown by the marked morphological changes and enhanced secretion of lysozyme, but also induced their prominent proliferation, as exhibited by enhanced DNA synthesis and the increased number of monocyte cell nuclei. The proliferation of monocytes was observed after the addition of physiological concentrations of calcitriol. Multinucleated giant cells were frequently observed among the monocytes. These marked morphological changes and the proliferation of monocytes were not observed in control cultures, which did not include calcitriol. These results indicate that calcitriol plays a critical role in the formation of the sarcoid granuloma and give an explanation of some of the clinical findings on sarcoidosis. In view of the evidence that sarcoid macrophages convert 25(OH)D3 to calcitriol, our results raise the possibility that the active metabolite of vitamin D3, which may be produced by macrophage-epithelioid cells, induces the differentiation and proliferation of circulating monocytes into macrophage-epithelioid cells, which in turn form sarcoidosis granulomas. This autostimulation mechanism of sarcoid granuloma formation may provide a model for future studies.