Junji Suzumiya

Heterozygous ITGA2B R995W mutation inducing constitutive activation of the αIIbβ3 receptor affects proplatelet formation and causes congenital macrothrombocytopenia

Congenital macrothrombocytopenia is a genetically heterogeneous group of rare disorders. αIIbβ3 has not been implicated in these conditions. We identified a novel, conserved heterozygous ITGA2B R995W mutation in 4 unrelated families. The surface expression of platelet αIIbβ3 was decreased to 50% to 70% of control. There was spontaneous PAC-1 and fibrinogen binding to resting platelets without CD62p expression. The activation state of αIIbβ3 in 293T cells was higher for αIIb-W995 than for β3-H723 but was weaker than for β3-N562. FAK was spontaneously phosphorylated in αIIb-W995/β3-transfected 293T cells. These results indicate that αIIb-W995/β3 has a constitutive, activated conformation but does not induce platelet activation. αIIb-W995/β3-transfected CHO cells developed membrane ruffling and abnormal cytoplasmic protrusions. The increased size and decreased number of proplatelet tips in αIIb-W995/β3-transduced mouse fetal liver-derived megakaryocytes indicate defective pro-platelet formation. We propose that activating mutations in ITGA2B and ITGB3 represent the etiology of a subset of congenital macrothrombocytopenias.

Aggressive natural killer cell leukemia: Therapeutic potential of l-asparaginase and allogeneic hematopoietic stem cell transplantation

We conducted a retrospective Japan–Korea multicenter study to better elucidate the clinicopathologic features and therapeutic modalities for aggressive natural killer cell leukemia (ANKL). A total of 34 patients were analyzed. The median age of the patients was 40 years. Among the patients in the study, four had a history of Epstein–Barr virus‐related disorders. Three types of ANKL cells were categorized according to their morphological features. Leukemic cells were below 20% in both peripheral blood and bone marrow of 11 patients. The clinical characteristics and prognoses of these 11 patients did not differ significantly from those of the others. As an initial therapy, l‐asparaginase chemotherapy resulted in a better response. A total of six patients received allogeneic hematopoietic stem cell transplantation (HSCT) and two received autologous HSCT, with all in non‐complete remission (CR). After HSCT, four with allogeneic and one with autologous HSCT reached CR. Median survival of all patients was 51 days. Median survival for the patients with and without HSCT were 266 and 36 days, respectively. A total of two patients with allogeneic HSCT were alive and in CR. All patients without HSCT died of ANKL. The use of l‐asparaginase was indicated as a factor for longer survival (HR 0.33, 95% confidence interval; 0.13–0.83, P = 0.02). Early diagnosis of ANKL, l‐asparaginase‐based chemotherapy and allogeneic HSCT might lead to improved patient outcomes. (Cancer Sci 2012; 103: 1079–1083)

Long-term survival following autologous and allogeneic stem cell transplantation for blastic plasmacytoid dendritic cell neoplasm

We sought to clarify the role of high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (auto-HSCT) and allogeneic hematopoietic stem cell transplantation (allo-HSCT) to treat blastic plasmacytoid dendritic cell neoplasm (BPDCN). We retrospectively identified 25 BPDCN patients (allo-HSCT, n = 14; auto-HSCT, n = 11) from registry data of the Japan Society for Hematopoietic Cell Transplantation and analyzed clinicopathologic data and clinical outcomes after transplantation. The median age at HSCT was 58 years (range, 17-67 years). All 11 patients who underwent auto-HSCT were in the first complete remission (CR1). With a median follow-up of 53.5 months, the overall survival rates at 4 years for patients who underwent auto-HSCT and allo-HSCT were 82% and 53% (P = .11), respectively, and progression-free survival rates were 73% and 48% (P = .14), respectively. Auto-HSCT for BPDCN in CR1 appears to provide promising results and deserves further evaluation in the setting of prospective trials.

Extranodal natural killer/T-cell lymphoma involving the gastrointestinal tract: Analysis of clinical features and outcomes from the Asia Lymphoma study group

BackgroundThe gastrointestinal (GI) tract is one of the most common extranasal sites in extranodal NK/T-cell lymphoma (ENKTL). However, data regarding ENKTL involving the GI tract are relatively scarce. Thus, we performed a multicenter, multinational retrospective study to analyze clinical features and treatment outcomes of ENKTL involving the GI tract.Patients and methodsPatients with ENKTL involving the GI tract diagnosed in twelve participating centers between 1991 and 2012 were retrospectively analyzed from five Asian countries.ResultsThe analysis of 81 patients with ENKTL involving the GI tract revealed that more than 60% of patients presented as advanced disease with B symptoms. 55 patients (68%) had GI manifestations including abdominal pain (n = 26, 32%), GI tract bleeding (n = 17, 21%) and bowel perforation (n = 12, 15%). The most common GI site was the small intestine, including the jejunum and ileum (n = 57, 70.3%). There were 34 patients (42%) who received systemic chemotherapy while 33 patients (41%) underwent surgery plus chemotherapy. However, 35 patients (43%) died due to disease progression, and treatment-related mortality including sepsis occurred in 17 patients (21%). Thus, the median overall survival was 7.8xa0months (95% Confidence interval: 3.9 – 11.7xa0months). Patients who could undergo surgery plus chemotherapy showed a trend of better survival than those treated with chemotherapy alone.ConclusionOverall, the data indicated that ENKTL involving the GI tract has a dismal prognosis despite active treatment including chemotherapy and surgery. Thus, more effective treatment strategies are required for this disease entity.

High-Dose Chemotherapy with Autologous Stem Cell Transplantation for Elderly Patients with Relapsed/Refractory Diffuse Large B Cell Lymphoma: A Nationwide Retrospective Study

The number of elderly patients with diffuse large B cell lymphoma (DLBCL) continues to increase but the data regarding autologous stem cell transplantation (ASCT) for elderly patients are limited. We analyzed 484 patients, ages 60 years or over, diagnosed with relapsed/refractory DLBCL who received ASCT from 1993 to 2010 in the Japan Society for Hematopoietic Cell Transplantation database. Median age was 64 years (range, 60 to 78). To evaluate the impact of age at ASCT, patients were classified into 3 groups: those between the ages of 60 to 64, 65 to 69, and 70 years or over. Overall nonrelapse mortality (NRM) at day 100, 1 year, and 2 years was 4.1%, 5.9% and 7.7%, respectively. NRM did not significantly differ among age groups (P = .60). Two-year progression-free survival (PFS) and overall survival (OS) were 48% and 58%, respectively. PFS and OS were significantly longer in patients 60 to 64 years old; however, the survival rate was acceptable even in those 70 or over, with a 2-year OS of 46%. ASCT is feasible in selected elderly patients and age alone should not be a contraindication for ASCT. Eligibility should be individualized and identification of a subset of elderly patients at high risk of treatment-related morbidity or mortality warrants investigation.

Imatinib mesylate inhibits cell growth of malignant peripheral nerve sheath tumors in vitro and in vivo through suppression of PDGFR-β

BackgroundMalignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive and associated with poor prognosis. Basic research to develop new treatment regimens is critically needed.MethodsThe effects of imatinib mesylate on MPNSTs were examined in six human MPNST cell lines and in a xenograft mouse model.ResultsThe results showed expression of platelet-derived growth factor receptor-β and suppression of its phosphorylation by imatinib mesylate in all six cell lines. Imatinib mesylate effectively suppressed MPNST cell growth in vitro at concentrations similar to those used clinically (1.46u2009−u20094.6 μM) in three of six cell lines. Knockdown of PDGFR-β by transfection with a specific siRNA also caused significant reduction in cell proliferation in the sensitive cell lines, but not in the resistant cell lines. Furthermore, imatinib mesylate also significantly suppressed colony formation within soft agar and tumor growth in xenograft models using two of the three sensitive MPNST cell lines. There was excellent agreement between in vitro and in vivo sensitivity to imatinib mesylate, suggesting possible selection of imatinib-sensitive tumors by in vitro analysis.ConclusionsThe results suggest that imatinib mesylate may be useful in the treatment of MPNST patients and in vitro studies may help select cells that are sensitive to imatinib mesylate in vivo.

Haematopoietic stem cell transplantation for relapsed or refractory anaplastic large cell lymphoma: a study of children and adolescents in Japan

To evaluate haematopoietic stem cell transplantation (HSCT) in children and adolescents, we reviewed the records of 47 patients who were ≤18 years, had relapsed or refractory anaplastic large cell lymphoma, and received HSCT between 1990 and 2010. At HSCT, complete remission (CR) was less common in allogeneic HSCT recipients (n = 24) than in autologous HSCT recipients (n = 23) (P = 0·01). The autologous and allogeneic HSCT groups differed in terms of 5‐year event‐free survival (EFS) (38% vs. 50%, P = 0·63), cumulative incidence of progress or relapse (49% vs. 28%, P = 0·25), and treatment‐related mortality (12% vs. 25%, P = 0·40). However, these differences were not significant. Patients with non‐CR at autologous HSCT had a significantly lower EFS rate (14% vs. 48%, P = 0·03). Conversely, although those with non‐CR at allogeneic HSCT had a lower EFS rate, this was not significant (44% vs. 63%, P = 0·26). Reduced‐intensity conditioning regimens were used for three of the 16 allogeneic HSCTs received by patients with non‐CR. These three patients achieved CR, surviving 32–65 months after HSCT. These results demonstrated that allogeneic HSCT might be a treatment option for patients who do not achieve CR through conventional chemotherapy.

Cyclopamine induces eosinophilic differentiation and upregulates CD44 expression in myeloid leukemia cells.

Cyclopamine, a plant-derived steroidal alkaloid, inhibits the hedgehog (Hh) signaling pathway by antagonizing Smoothened. This drug can induce the differentiation of myeloid leukemia cell lines and acute myeloid leukemia (AML) cells in primary culture. The treated cells were stained with Luxol-fast-blue, which is specific for eosinophilic granules. Ligation of CD44 with some specific monoclonal antibodies can reverse the differentiation of AML cells. Combined treatment with cyclopamine and a monoclonal antibody to ligate CD44 more than additively induced the differentiation of HL-60 cells. These results may provide useful information for the development of a CD44-targeted therapy in AML.

Synthetic emmprin peptides with chitobiose substitution stimulate MMP-2 production by fibroblasts.

BackgroundEmmprin, a glycoprotein containing two Ig domains, is enriched on tumor cell surfaces and stimulates matrix metalloproteinase (MMP) production by adjacent stromal cells. Its first Ig domain (ECI) contains the biologically active site. The dependence of emmprin activity on N-glycosylation is controversial. We investigated whether synthetic ECI with the shortest sugar is functionally active.MethodsThe whole ECI peptides carrying sugar chains, a chitobiose unit or N-linked core pentasaccharide, were synthesized by the thioester method and added to fibroblasts to examine whether they stimulate MMP-2 production.ResultsECI carrying a chitobiose unit, ECI-(GlcNAc) 2, but not ECI without a chitobiose unit or the chitobiose unit alone, dose-dependently stimulated MMP-2 production by fibroblasts. ECI with longer chitobiose units, ECI-[(Man)3(GlcNAc)2], also stimulated MMP-2 production, but the extent of its stimulation was lower than that of ECI-(GlcNAc)2.ConclusionsOur results indicate that ECI can mimic emmprin activity when substituted with chitobiose, the disaccharide with which N-glycosylation starts.

Combined treatment with tamoxifen and a fusicoccin derivative (ISIR-042) to overcome resistance to therapy and to enhance the antitumor activity of 5-fluorouracil and gemcitabine in pancreatic cancer cells.

Although progress has been made in chemotherapeutic strategies against pancreatic cancer, overall survival has not significantly improved over the past decade. Thus, the development of better therapeutic regimens remains a high priority. Pancreatic cancer cell lines were treated with tamoxifen, a novel antitumor fusicoccin derivative (ISIR-042), and anticancer drugs, and their effects on cell growth, signaling and gene expression were determined. Xenografts of Panc-1 cells were treated with tamoxifen, ISIR-042 and 5-fluorouracil (5FU) to determine the effects on tumor growth. The inhibition of the growth of pancreatic cancer cells induced by tamoxifen was effectively reduced by α-tocopherol, a membrane stabilizer. ISIR-042 produced synergistic effects with tamoxifen in inhibiting cell growth. Tamoxifen elevated lipid peroxidation and the release of cytochrome c, and these effects of tamoxifen were reduced by α-tocopherol. ISIR-042 significantly inhibited colony formation and the expression of stemness-related genes of pancreatic cancer cells. The triple combination of tamoxifen, ISIR-042, and 5FU or gemcitabine was effective at inhibiting cell growth and the appearance of drug-resistant cells. This combined treatment significantly inhibited the growth of Panc-1 cells as xenografts without apparent adverse effects. The triple combination of tamoxifen and ISIR-042 with 5FU or gemcitabine may be highly effective against pancreatic cancer by overcoming resistance to therapy.