Ken-ichiro Watanabe

Outcome of hepatoblastomas treated using the Japanese Study Group for Pediatric Liver Tumor (JPLT) protocol-2: report from the JPLT

BackgroundIn the recent years, surgical resection with pre- and/or postoperative chemotherapy has markedly improved the survival rate of hepatoblastoma patients. We herein report the results of patients treated with the current protocol of the Japanese Study Group for Pediatric Liver Tumor, JPLT-2.MethodsA total of 279 patients with malignant liver tumor were enrolled in JPLT-2. Data from 212 hepatoblastoma cases were analyzed. PRETEXT I patients were treated with primary resection followed by low doses of cisplatin–pirarubicin (tetrahydropyranyl-adriamycin). Otherwise, patients received preoperative cisplatin–pirarubicin (CITA), followed by surgery and postoperative chemotherapy. Ifosfamide, pirarubicin, etoposide, and carboplatin (ITEC) were given as a salvage treatment. High-dose chemotherapy with hematopoietic stem cell transplantation (SCT) was reserved for patients with metastatic diseases.ResultsThe 5-year overall survival rate (OS) in non-metastatic cases was 100% for PRETEXT I, 87.1% for PRETEXT II, 89.7% for PRETEXT III, and 78.3% for PRETEXT IV. The 5-year OS in metastatic cases was 43.9%. The outcome in non-metastatic PRETEXT IV cases was markedly improved, while the results of metastatic tumors remained poor.ConclusionsJPLT-2 protocol achieved satisfactory survival among children with non-metastatic hepatoblastoma. New approaches are needed for patients with metastatic diseases.

SBDS-deficient cells undergo accelerated apoptosis through the Fas-pathway

Ninety percent of patients with Shwachman-Diamond syndrome, an inherited bone marrow dysfunction, have mutations in the Shwachman-Bodian-Diamond syndrome gene (SBDS). However, the relationship between SBDS and cell survival is unknown. This study shows that inhibition of SBDS results in accelerated apoptosis and investigates the mechanisms involved in this process. Background Shwachman-Diamond syndrome is an inherited multisystem disorder characterized by bone marrow and pancreatic dysfunction as well as metaphyseal dysostosis. Ninety percent of the patients have mutations in the Shwachman-Bodian-Diamond syndrome gene (SBDS). The relationship between SBDS and cell survival is unknown. In this study we investigated whether deficiency of the SBDS protein can cause increased apoptosis and, if so, what pathways are involved in this process. Design and Methods To determine whether accelerated apoptosis of Shwachman-Diamond syndrome cells is caused by a deficiency in SBDS we generated two SBDS-knockdown cell clones. We then evaluated, Fas expression and levels of the intracellular proteins, BAX, BCL-2 and BCL-XL and determined the effects of apoptosis inhibitors. Using oligonucteotide-microarrays we also analyzed apoptosis-related gene expression in Shwachman-Diamond syndrome marrow cells. Results We found that knocking down SBDS by short interfering hairpin RNA in HeLa cells resulted in a prominent increase in cell death. The mechanism for the accelerated apoptosis was related to marked hypersensitivity to Fas stimulation, and increased Fas expression. In contrast, there was no increase in the expression ratio of the pro-apoptotic factor, BAX, to the pro-survival factors, BCL2 and BCL-XL in the SBDS-knockdown cells and in the patients’ marrow cells. Furthermore, inhibition of Fas and caspase 8, but not caspase 9, significantly improved the defective cell growth phenotype. Conclusions Our work provides new data about the pro-survival properties of SBDS, whose inhibition results in accelerated apoptosis through the Fas pathway.

Loss of function mutations in RPL27 and RPS27 identified by whole-exome sequencing in Diamond-Blackfan anaemia

Diamond‐Blackfan anaemia is a congenital bone marrow failure syndrome that is characterized by red blood cell aplasia. The disease has been associated with mutations or large deletions in 11 ribosomal protein genes including RPS7, RPS10, RPS17, RPS19, RPS24, RPS26, RPS29, RPL5, RPL11, RPL26 and RPL35A as well as GATA1 in more than 50% of patients. However, the molecular aetiology of many Diamond‐Blackfan anaemia cases remains to be uncovered. To identify new mutations responsible for Diamond‐Blackfan anaemia, we performed whole‐exome sequencing analysis of 48 patients with no documented mutations/deletions involving known Diamond‐Blackfan anaemia genes except for RPS7, RPL26, RPS29 and GATA1. Here, we identified a de novo splicing error mutation in RPL27 and frameshift deletion in RPS27 in sporadic patients with Diamond‐Blackfan anaemia. In vitro knockdown of gene expression disturbed pre‐ribosomal RNA processing. Zebrafish models of rpl27 and rps27 mutations showed impairments of erythrocyte production and tail and/or brain development. Additional novel mutations were found in eight patients, including RPL3L, RPL6, RPL7L1T, RPL8, RPL13, RPL14, RPL18A and RPL31. In conclusion, we identified novel germline mutations of two ribosomal protein genes responsible for Diamond‐Blackfan anaemia, further confirming the concept that mutations in ribosomal protein genes lead to Diamond‐Blackfan anaemia.

Neutrophil differentiation from human-induced pluripotent stem cells

Induced pluripotent stem (iPS) cells are of potential value not only for regenerative medicine, but also for disease investigation. The present study describes the development of a neutrophil differentiation system from human iPS cells (hiPSCs) and the analysis of neutrophil function and differentiation. The culture system used consisted of the transfer of hiPSCs onto OP9 cells and their culture with vascular endothelial growth factor (VEGF). After 10 days, TRA 1‐85+CD34+VEGF receptor‐2 (VEGFR‐2)high cells were sorted and co‐cultured with OP9 cells in the presence of hematopoietic cytokines for 30 days. Floating cells were collected and subjected to morphological and functional analysis. These hiPSC‐derived neutrophils were similar to peripheral blood mature neutrophils in morphology, contained functional neutrophil specific granules, and were equipped with the basic functions such as phagocytosis, superoxide production, and chemotaxis. In the process of differentiation, myeloid cells appeared sequentially from immature myeloblasts to mature segmented neutrophils. Expression patterns of surface antigen, transcription factors, and granule proteins during differentiation were also similar to those of granulopoiesis in normal bone marrow. In conclusion, differentiation of mature neutrophils from hiPSCs was successfully induced in a similar process to normal granulopoiesis using an OP9 co‐culture system. This system may be applied to elucidate the pathogenesis of various hematological diseases that affect neutrophils. J. Cell. Physiol. 226: 1283–1291, 2011.

Risk-stratified staging in paediatric hepatoblastoma: a unified analysis from the Children's Hepatic tumors International Collaboration

BACKGROUND Comparative assessment of treatment results in paediatric hepatoblastoma trials has been hampered by small patient numbers and the use of multiple disparate staging systems by the four major trial groups. To address this challenge, we formed a global coalition, the Childrens Hepatic tumors International Collaboration (CHIC), with the aim of creating a common approach to staging and risk stratification in this rare cancer. METHODS The CHIC steering committee-consisting of leadership from the four major cooperative trial groups (the International Childhood Liver Tumours Strategy Group, Childrens Oncology Group, the German Society for Paediatric Oncology and Haematology, and the Japanese Study Group for Paediatric Liver Tumours)-created a shared international database that includes comprehensive data from 1605 children treated in eight multicentre hepatoblastoma trials over 25 years. Diagnostic factors found to be most prognostic on initial analysis were PRETreatment EXTent of disease (PRETEXT) group; age younger than 3 years, 3-7 years, and 8 years or older; α fetoprotein (AFP) concentration of 100 ng/mL or lower and 101-1000 ng/mL; and the PRETEXT annotation factors metastatic disease (M), macrovascular involvement of all hepatic veins (V) or portal bifurcation (P), contiguous extrahepatic tumour (E), multifocal tumour (F), and spontaneous rupture (R). We defined five clinically relevant backbone groups on the basis of established prognostic factors: PRETEXT I/II, PRETEXT III, PRETEXT IV, metastatic disease, and AFP concentration of 100 ng/mL or lower at diagnosis. We then carried the additional factors into a hierarchical backwards elimination multivariable analysis and used the results to create a new international staging system. RESULTS Within each backbone group, we identified constellations of factors that were most predictive of outcome in that group. The robustness of candidate models was then interrogated using the bootstrapping procedure. Using the clinically established PRETEXT groups I, II, III, and IV as our stems, we created risk stratification trees based on 5 year event-free survival and clinical applicability. We defined and adopted four risk groups: very low, low, intermediate, and high. INTERPRETATION We have created a unified global approach to risk stratification in children with hepatoblastoma on the basis of rigorous statistical interrogation of what is, to the best of our knowledge, the largest dataset ever assembled for this rare paediatric tumour. This achievement provides the structural framework for further collaboration and prospective international cooperative study, such as the Paediatric Hepatic International Tumour Trial (PHITT). FUNDING European Network for Cancer Research in Children and Adolescents, funded through the Framework Program 7 of the European Commission (grant number 261474); Childrens Oncology Group CureSearch grant contributed by the Hepatoblastoma Foundation; Practical Research for Innovative Cancer Control and Project Promoting Clinical Trials for Development of New Drugs and Medical Devices, Japan Agency for Medical Research; and Swiss Cancer Research grant.

Genetic correction of HAX1 in induced pluripotent stem cells from a patient with severe congenital neutropenia improves defective granulopoiesis

HAX1 was identified as the gene responsible for the autosomal recessive type of severe congenital neutropenia. However, the connection between mutations in the HAX1 gene and defective granulopoiesis in this disease has remained unclear, mainly due to the lack of a useful experimental model for this disease. In this study, we generated induced pluripotent stem cell lines from a patient presenting for severe congenital neutropenia with HAX1 gene deficiency, and analyzed their in vitro neutrophil differentiation potential by using a novel serum- and feeder-free directed differentiation culture system. Cytostaining and flow cytometric analyses of myeloid cells differentiated from patient-derived induced pluripotent stem cells showed arrest at the myeloid progenitor stage and apoptotic predisposition, both of which replicated abnormal granulopoiesis. Moreover, lentiviral transduction of the HAX1 cDNA into patient-derived induced pluripotent stem cells reversed disease-related abnormal granulopoiesis. This in vitro neutrophil differentiation system, which uses patient-derived induced pluripotent stem cells for disease investigation, may serve as a novel experimental model and a platform for high-throughput screening of drugs for various congenital neutrophil disorders in the future.

First-line treatment for severe aplastic anemia in children: bone marrow transplantation from a matched family donor versus immunosuppressive therapy

The current treatment approach for severe aplastic anemia in children is based on studies performed in the 1980s, and updated evidence is required. We retrospectively compared the outcomes of children with acquired severe aplastic anemia who received immunosuppressive therapy within prospective trials conducted by the Japanese Childhood Aplastic Anemia Study Group or who underwent bone marrow transplantation from an HLA-matched family donor registered in the Japanese Society for Hematopoietic Cell Transplantation Registry. Between 1992 and 2009, 599 children (younger than 17 years) with severe aplastic anemia received a bone marrow transplant from an HLA-matched family donor (n=213) or immunosuppressive therapy (n=386) as first-line treatment. While the overall survival did not differ between patients treated with immunosuppressive therapy or bone marrow transplantation [88% (95% confidence interval: 86–90) versus 92% (90–94)], failure-free survival was significantly inferior in patients receiving immunosuppressive therapy than in those undergoing bone marrow transplantation [56% (54–59) versus 87% (85–90); P<0.0001]. There was no significant improvement in outcomes over the two time periods (1992–1999 versus 2000–2009). In multivariate analysis, age <10 years was identified as a favorable factor for overall survival (P=0.007), and choice of first-line immunosuppressive therapy was the only unfavorable factor for failure-free survival (P<0.0001). These support the current algorithm for treatment decisions, which recommends bone marrow transplantation when an HLA-matched family donor is available in pediatric severe aplastic anemia.

Telomere shortening in peripheral blood cells was related with aging but not with white blood cell count

SummaryTelomeres in somatic cells are progressively shortened with aging. We investigated the relationship between the telomere length and other factors which may affect the frequency of cell divisions, in peripheral blood cells. Shortening of telomeric repeats was correlated with aging (p<0.0001), but not with white blood cell count, neutrophil count, and smoking habit. Not only the number of cell divisions, but also some other factors, such as upregulation level of telomerase activity concomitant with the cell division in hematopoietic progenitor cells, might affect the length of telomeric repeats in blood cells.

Repeat resection of pulmonary metastasis is beneficial for patients with osteosarcoma of the extremities

Pulmonary metastasectomy in osteosarcoma can lead to long-term survival, but the role for repeat pulmonary metastasectomy is undefined. To confirm the value of repeat pulmonary resection of recurrent pulmonary metastases, we herein reviewed our institutional experience. Between 1989 and 2007, 25 patients with pulmonary metastases from osteosarcomas of the extremities underwent pulmonary resection, and 14 patients underwent repeat pulmonary metastasectomy. Ten of 14 patients underwent complete resection. Various perioperative variables were investigated retrospectively in these patients to confirm a role for repeat metastasectomy and analyze prognostic factors for overall survival (OS) after repeat pulmonary metastasectomy. OS rate after repeat pulmonary metastasectomy was 43% at two years and 19% at five years. On multivariate analysis, patients with complete resection presented significantly favorable OS (P=0.02). Interestingly enough, survival curve of patients with complete resection after the first pulmonary metastasectomy was almost the same as that of patients with complete resection after the second pulmonary metastasectomy. In conclusion, patients with complete resection for recurrent pulmonary metastasis show a significantly better prognosis after repeat pulmonary metastasectomy. Our data imply that repeat pulmonary metastasectomy might be beneficial because it can salvage a subset of patients with osteosarcoma who retain favorable prognostic determinants.

Successful T-cell-replete peripheral blood stem cell transplantation from HLA-haploidentical microchimeric mother to daughter with refractory acute lymphoblastic leukemia using reduced-intensity conditioning

Summary:A 16-year-old girl with refractory acute lymphoblastic leukemia underwent reduced-intensity hematopoietic stem cell transplantation from her two-locus-mismatched haploidentical mother, who was microchimeric for the patients hematopoietic cells. The conditioning regimen comprised melphalan, fludarabine, and low-dose total body irradiation. Non-T-cell-depleted peripheral blood stem cells were infused with graft-versus-host disease (GVHD) prophylaxis consisting of tacrolimus, prednisolone, and short-course methotrexate. Complete donor-type engraftment without evidence of residual leukemia was confirmed on day 22. Severe GVHD was not observed despite rapid cessation of immunosuppression. The patient remains well in continuous remission 15 months after transplant. This successful experience suggests that maternal hematopoietic stem cell transplants for children, in the presence of microchimerism, may be associated with hyporesponsiveness to the inherited paternal HLA antigens (IPA); preventing severe GVHD.