Overexpression of BMI-1 correlates with drug resistance in B-cell lymphoma cells through the stabilization of survivin expression.

The expression of BMI-1 is correlated with disease progression in cancer patients. We showed that ectopic expression of BMI-1 in B-cell lymphoma cell lines, HT and RL, conferred resistance to etoposide and oxaliplatin, known to enhance sensitivity by targeting the survivin gene, but not to irinotecan, which is not relevant to the downregulation of survivin expression. The expression of survivin was not only augmented in cells transduced with BMI-1, but persisted in the presence of etoposide in cells overexpressing BMI-1. By contrast, the mock-transduced cells succumbed in the medium with anticancer drugs, with an accompanying decrease in BMI-1 and survivin expression. BMI-1 overexpression stabilized survivin post-translationally without an accompanying rise in the mRNA, suggesting survivin as a potential target for BMI-1. Knockdown of either BMI-1 or survivin restored sensitivity to etoposide in the BMI-1-overexpressing lymphoma cells. An analysis of six patients with B-cell lymphoma showed that in the drug-resistant patients, levels of BMI-1 and survivin were maintained even after drug administration. However, downregulation of both BMI-1 and survivin expression was observed in the drug-sensitive patients. Therefore, BMI-1 might facilitate drug resistance in B-cell lymphoma cells through the regulation of survivin. BMI-1 could be an important prognostic marker as well as a future therapeutic target in the treatment of drug-resistant lymphomas.

Clinical and genetic features of therapy-related myeloid neoplasms after chemotherapy for acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is a highly curable disease with excellent complete remission and long-term survival rates. However, the development of therapy-related myeloid neoplasms (t-MN) is being reported with increasing frequency in patients successfully treated for APL. We attempted to clarify the different clinical features and hematologic findings between t-MN and relapse cases, and to identify gene alterations involved in t-MN. We compared 10 relapse and 11 t-MN cases that developed in 108 patients during their first complete remission from APL. At APL diagnosis, t-MN patients had lower white blood cell counts than did relapse patients (P = .048). Overall survival starting from chemotherapy was significantly worse in t-MN patients than in relapse patients (P = .022). The t-MN cases were characterized as CD34(+)/HLA-DR(+) and PML-RARA(-), and 4 RUNX1/AML1 mutations were detected. T-MN is easily distinguished from APL relapse by evaluating these hematologic features, and it may originate from primitive myeloid cells by chemotherapy-induced RUNX1 mutations.

[Successful treatment with bortezomib for a patient with plasma cell leukemia accompanied by severe hyperbilirubinemia].

A 59-year-old woman was admitted to our hospital with jaundice, renal dysfunction, anemia and hypercalcemia. Primary plasma cell leukemia (PCL) was diagnosed based on findings of IgA-λ type M-protein, 22% plasma cells in the bone marrow and 23.1% plasma cells of WBC in the peripheral blood. Because the total bilirubin (T.Bil) level increased even after the administration of prednisolone (PSL), dexamethasone and methylprednisolone, the patient was started on bortezomib (0.7 mg/m(2) on days 1, 4, 8 and 11 for 3 weeks) combined with PSL (40 mg/day). The level of T.Bil decreased and the patient's condition remarkably improved. We then increased the dose of bortezomib to 1.0 mg/m(2) in the second course, but discontinued treatment just after starting the third course because NCI-CTCAE Grade 3 peripheral neuropathy developed. According to the criteria of the International Myeloma Working Group, the response category was VGPR (=very good partial response) at 1 month after pausing treatment. We recommend these novel agents for PCL, which is an aggressive form of extramedullary plasma cell cancer.

[Radiation associated leukemia and myelodysplastic syndrome].

Leukemias including acute myeloid leukemia (AML), acute lymphocytic leukemia, and chronic myeloid leukemia as well as myelodysplastic syndrome (MDS), male non-Hodgkin lymphoma and MGUS are statistically significant radiation-associated hematopoietic neoplasms. Recently, MDS has been confirmed to increase among atomic bomb survivors. AML/RUNX1 is a critical transcription factor of differentiation and proliferation of hematopoietic stem cells. AML1 point mutations, especially N-terminal RUNT domain in-frame type, are frequently detected in radiaton-associated and therapy-related (rad-t-) MDS/AML. In addition, the point mutations, are frequently associated with additional mutations in receptor tyrosine kinase (RTK)-RAS pathway, including FLT3, N-RAS, SHP2 and NF1. The combination of AML1/RUNX1 mutation and RTK-RAS pathway mutation in hematopoietic stem cells is considered responsible for the oncogenesis of rad-t- MDS/AML.

AML1/RUNX1 point mutation possibly promotes leukemic transformation in myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders characterized by proliferation of one or more myeloid cell lineages. Some patients exhibit leukemic transformation (LT) by unknown mechanisms, and chemotherapy may increase the risk of LT. To clarify the molecular mechanisms of LT, gene alterations involved in LT from patients in the chronic phase (CP) of MPNs were identified. Among 18 patients who progressed to leukemia, AML1/RUNX1 mutations were detected in 5 patients at the LT but in none at the CP. To investigate the leukemogenic effect of AML1/RUNX1 mutants, the AML1D171N mutant was transduced into CD34(+) cells from patients in the CP of MPNs. The D171N transduction resulted in proliferation of immature myeloid cells, enhanced self-renewal capacity, and proliferation of primitive progenitors. Taken together, these results indicate that AML1/RUNX1 point mutations may have a leukemogenic potential in MPN stem cells, and they may promote leukemic transformation in MPN.

[Successful treatment with low-dose dasatinib in a patient with chronic eosinophilic leukemia intolerant to imatinib].

A 77-year-old man with cough and dyspnea was admitted to hospital. Chest X-ray demonstrated reticulated shadows in the bilateral inferior lung fields and marked eosinophilia was detected in peripheral blood. Although he received steroid pulse therapy, eosinophilia became more serious and he was referred to our hospital. Bone marrow examination demonstrated a hypercellular marrow that consisted predominantly of dysplastic eosinophils with differentiation. FISH analysis of bone marrow cells demonstrated 4q12 deletion and RT-PCR analysis detected FIP1L1-PDGFRA fusion gene, leading to the diagnosis of chronic eosinophilic leukemia (CEL). Treatment with low-dose imatinib was immediately initiated; however, drug-induced systemic edema was progressive and became intolerable. Therefore, we changed imatinib to low-dose dasatinib (20 mg/day), resulting in complete molecular response of CEL after 3 months without any severe adverse effects. This is the first report on the efficacy of low-dose dasatinib for the treatment of CEL. The peak level (Cmax) of dasatinib in this patient was 55.3 nM, which exceeded the concentration of dasatinib required to inhibit cells with FIP1L1-PDGFRA by 50%. Thus, low-dose dasatinib with therapeutic drug monitoring can be a useful therapy for imatinib-intolerant CEL even in elderly patients.

Synergistic and persistent effect of T-cell immunotherapy with anti-CD19 or anti-CD38 chimeric receptor in conjunction with rituximab on B-cell non-Hodgkin lymphoma.

Using artificial receptors, it is possible to redirect the specificity of immune cells to tumour-associated antigens, which is expected to provide a useful strategy for cancer immunotherapy. Given that B-cell non-Hodgkin lymphoma (B-NHL) cells invariably express CD19 and CD38, these antigens may be suitable molecular candidates for such immunotherapy. We transduced human peripheral T cells or a T-cell line with either anti-CD19-chimeric receptor (CAR) or anti-CD38-CAR, which contained an anti-CD19 or anti-CD38 antibody-derived single-chain variable domain respectively. Retroviral transduction led to anti-CD19-CAR or anti-CD38-CAR expression in T cells with high efficiency (>60%). The T cell line, Hut78, when transduced with anti-CD19-CAR or anti-CD38-CAR, exerted strong cytotoxicity against the B-NHL cell lines, HT and RL, and lymphoma cells isolated from patients. Interestingly, use of both CARs had an additive cytotoxic effect on HT cells in vitro. In conjunction with rituximab, human peripheral T cells expressing either anti-CD19-CAR or anti-CD38-CAR enhanced cytotoxicity against HT-luciferase cells in xenografted mice. Moreover, the synergistic tumour-suppressing activity was persistent in vivo for over 2 months. These results provide a powerful rationale for clinical testing of the combination of rituximab with autologous T cells carrying either CAR on aggressive or relapsed B-NHLs.

BMI-1 expression is enhanced through transcriptional and posttranscriptional regulation during the progression of chronic myeloid leukemia.

BMI-1 plays a critical role in regulating the activity of hematopoietic stem and progenitor cells. Patients with chronic myeloid leukemia (CML) are at a risk of developing blastic crisis (BC) even after the emergence of imatinib mesylate. In this study, to determine the relevance of BMI-1 to BC, we investigated the expression of BMI-1 in CD34(+) cells at each of the chronic phase (CP), the accelerated phase (AP), and BC by flow cytometry. Interestingly, the level of BMI-1 expression was significantly higher in CP than in controls and was further increased during the course of the disease progression (control--5.66%; CP--36.93%; AP and BC--76.41%). Curiously, mRNA levels for BMI-1 were almost consistent during the disease progression from CP to BC (control--2.21; CP--9.77; AP and BC--9.70 (BMI-1/glyceraldehyde-3-phosphate dehydrogenase ratio)). Since we further found that overexpression of BCR-ABL in human embryonic kidney-293 cells enhanced BMI-1 expression and that BMI-1 expression was increased in K562 cells, derived from patients with BC, in the presence of proteasomal inhibitors, BMI-1 was presumed to be positively regulated by BCR-ABL and further by posttranscriptional modification in the course of the disease progression. We suggest the usefulness of BMI-1 expression in CD34(+) cells as a molecular marker for monitoring patients with CML.

Acquired pure red cell aplasia associated with malignant lymphomas: a nationwide cohort study in Japan for the PRCA Collaborative Study Group.

Pure red cell aplasia (PRCA) has been reported in association with lymphoma as one of the autoimmune diseases seen during the course of lymphoid malignancies. However, the relation of PRCA with the underlying lymphomas remains unclear. The aim of this study was to clarify the histologic subtypes of lymphomas, the chronological sequence of anemia and lymphoma, and the response to treatment. We conducted a nationwide survey in Japan. From a cohort of 185 PRCA patients, 8 patients with lymphoma were evaluated. Histologic subtypes varied and the lymphoma was of the B-cell type in four cases and of the T-cell type in four. Four patients simultaneously developed PRCA and lymphoma. Three patients developed PRCA following lymphoma, two of whom developed anemia during remission of lymphoma. PRCA preceded lymphoma in one patient. Effective chemotherapy was associated with remission of anemia in concurrent lymphoma and PRCA. Overall, anemia responded to chemotherapy and/or immunosuppressive therapy in seven patients. In four responding patients, PRCA remained in durable remission without maintenance immunosuppressive therapy, which is different from a recurrent feature of idiopathic PRCA. We suggest that the mechanism of lymphoma-associated PRCA is heterogeneous and that durable maintenance-free remission of anemia can be obtained in some patients.

[Molecular mechanisms in myeloproliferative diseases and myelodysplastic syndromes].

Little was known about the mechanisms for myeloproliferative diseases (MPD) until 2005 when an activating mutation in the JAK2 tyrosine kinase (JAK2 V617F) was identified in >95% of patients with polycythemia vera (PV), and in a significant proportion of patients with essential thormbocythemia (ET) and primary myelofibrosis (PMF). Furthermore, activating abnormalities of some tyrosine kinases were identified in MPD and related diseases, suggesting that constitutive activation of the signaling pathway is a unifying feature of these diseases. On the other hand, the molecular mechanism of myelodysplastic syndromes (MDS) is still poorly understood. Recent study revealed that two types of AML1/RUNX1 mutants function via distinct molecular mechanisms to produce mutant-specific phenotypes of MDS. The mechanisms of MPD and MDS gradually become clear.

Osteoprogenitor differentiation is not affected by immunomodulatory thalidomide analogs but is promoted by low bortezomib concentration, while both agents suppress osteoclast differentiation.

We investigated the effects of bortezomib (PS-341) and immunomodulatory thalidomide analogs (immunomodulatory compounds; CC-4047, CC-6032, and CC-5013, or lenalidomide) on osteoblast and osteoclast differentiation in vitro using human mesenchymal stem cells (hMSC) to commit to osteoprogenitor cells and peripheral blood mononuclear cells (PBMCs) isolated from healthy donors, respectively. First, the concentration of bortezomib for an anti-myeloma effect was more than 1.0 nM in myeloma cells of multiple myeloma (MM) patients and more than 2.5 nM in myeloma cell lines. In contrast, anti-myeloma effects of immunomodulatory compounds on myeloma cells differed among myeloma cells and these compounds themselves. Subsequently, these agents (bortezomib; 0.5-5.0 nM, immunomodulatory compounds; 10 microM) were added to the osteoprogenitor cell culture media or the media for osteoclast differentiation. Low bortezomib concentrations (0.5 and 1.0 nM) increased ALP activity, and the delayed addition of bortezomib further increased ALP activity. Mineralized nodular formation with <2.5 nM bortezomib was not impaired. BMP2 expression on osteoprogenitor cells was found to increase in a time-dependent manner irrespective of treatment with bortezomib. On the other hand, the anti-osteoclast effect with low bortezomib concentration (< or =2.5 nM) depended on MM patients. In contrast, immunomodulatory compounds at 10 microM showed an anti-osteoclast effect without cytotoxicity to osteoblast differentiation, at which dose myeloma cells underwent apoptosis. These findings might improve the treatment strategy for MM patients without damaging BM stromal cells by combining bortezomib with immunomodulatory compounds.

Ectopic cyclin D1 overexpression increases chemosensitivity but not cell proliferation in multiple myeloma.

We established a myeloma cell line (RPMI8226) with cyclin D1 overexpression in which the transfected cyclin D1 gene was stably expressed. D1 transfectants showed down-regulation of cyclin D2. Cell proliferation analysis did not show any differences among RPMI8226, mock control, and D1 transfectants. The number of S-phase cells increased while the number of G0/G1- and G2/M-phase cells decreased in D1 transfectants, which indicates a prolonged S-phase caused by cyclin D1 transfection. A decreased number of G2/M-phase cells was also detected in myeloma cells of patients with translocation t(11;14)(q13;q32). Western blot analysis revealed an increase in the hyperphosphorylated form of retinoblastoma (Rb) protein in D1 transfectants; however, the expression of p53, p16, Bax, Bad, Bcl-2, and Mcl-1 did not significantly change. Treatment with anti-myeloma drugs (melphalan, dexamethasone, bortezomib and immunomodulatory compounds) induced apoptosis earlier in D1 transfectants compared with RPMI8226 and mock control via the activation of both caspase-8 and -9. However, we could not detect a relationship between cyclin D1 expression and the response to treatment with VAD and bortezomib. Therefore, we assume that high sensitivity to anti-myeloma drugs depends on the duration of the S-phase, but a clinical response might depend on the number of myeloma cells with cyclin D1 overexpression.

High frequency of AML1/RUNX1 point mutations in radiation-associated myelodysplastic syndrome around Semipalatinsk nuclear test site.

It is known that bone marrow is a sensitive organ to ionizing radiation, and many patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) have been diagnosed in radiation-treated cases and atomic bomb survivors in Hiroshima and Nagasaki. The AML1/RUNX1 gene has been known to be frequently mutated in MDS/AML patients among atomic bomb survivors and radiation therapy-related MDS/AML patients. In this study, we investigated the AML1 mutations in radiation-exposed patients with MDS/AML among the residents near the Semipalatinsk Nuclear Test Site (SNTS), where the risk of solid cancers and leukemias was increased due to the radiation effects. AML1 mutations were identified in 7 (39%) of 18 radiation-exposed MDS/AML patients. In contrast, no AML1 mutation was found in 13 unexposed MDS/AML cases. The frequency of AML1 mutations in radiation-exposed patients with MDS/AML was significantly higher compared with unexposed patients (p < 0.05).We also found a significant correlation between individual estimated doses and AML1 mutations (p < 0.05). Considering these results, AML1 point mutations might be a useful biomarker that differentiates radio-induced MDS/AML from spontaneous MDS/AML.

[Postpartum hemorrhage successfully treated with recombinant factor VIIa in Glanzmann thromboasthenia].

Glanzmann thrombasthenia is an inherited hemorrhagic disorder characterized by severe reduction or absence of platelet aggregation in response to multiple physiologic agonists due to qualitative or quantitative abnormalities of platelet glycoprotein (GP) IIb/IIIa. Treatment of bleeding episodes may require platelet transfusion. However, repeated platelet transfusions may result in GPIIb/IIIa and/or HLA immunization, and development of platelet refractoriness. Recently, a number of reports have suggested that recombinant factor VIIa product (rFVIIa) may be a therapeutic alternative in these situations. We have used rFVIIa to treat a 34-year-old primigravida woman for postpartum bleeding. She had been diagnosed with Glanzmann thrombasthenia at 32 years of age. At 37 weeks gestation, she underwent elective caesarean section uneventfully with platelet transfusion. Nine days later, she developed vaginal bleeding and received twenty units of platelet concentrates every day, but bleeding persisted. Thereafter, 4.8 mg intravenous rFVIIa was administered three times, which immediately arrested the bleeding. These results demonstrate that rFVIIa is effective for severe bleeding in Glanzmann thrombasthenia patients, especially in those with antiplatelet antibodies and/or platelet transfusion refractoriness.

Successful efavirenz dose reduction in HIV type 1-infected individuals with cytochrome P450 2B6 *6 and *26.

BACKGROUND: Efavirenz (EFV) is metabolized primarily by cytochrome P450 2B6 (CYP2B6), and high plasma concentrations of the drug are associated with a G-->T polymorphism at position 516 (516G-->T) of CYP2B6 and frequent central nervous system (CNS)-related side effects. Here, we tested the feasibility of genotype-based dose reduction of EFV. METHODS: CYP2B6 genotypes were determined in 456 human immunodeficiency virus type 1 (HIV-1)-infected patients who were receiving EFV treatment or were scheduled to receive EFV-containing treatment. EFV dose was reduced in CYP2B6 516G-->T carriers who had high plasma EFV concentrations while receiving the standard dosage (600 mg). EFV-naive homozygous CYP2B6 516G-->T carriers were treated with low-dose EFV. In both groups, the dose was further reduced when plasma EFV concentration remained high. RESULTS: CYP2B6 516G-->T was identified in the *6 allele (found in 17.9% of our subjects) and a novel allele, *26 (found in 1.3% of our patients). All EFV-treated CYP2B6 *6/*6 and *6/*26 carriers had extremely high plasma EFV concentrations (>6000 ng/mL) while receiving the standard dosage. EFV dose was reduced to 400 mg for 11 patients and to 200 mg for 7 patients with persistently suppressed HIV-1 loads. EFV-containing treatment was initiated at 400 mg in 4 CYP2B6 *6/*6 carriers and one *6/*26 carrier. Two of them still had a high plasma EFV concentration while receiving that dose, and the dose was further reduced to 200 mg, with successful HIV-1 suppression. CNS-related symptoms improved with dose reduction in 10 of the 14 patients, although some had not been aware of the symptoms at initial dosage. CONCLUSIONS: Genotype-based EFV dose reduction is feasible in CYP2B6 *6/*6 and *6/*26 carriers, which can reduce EFV-associated CNS symptoms.

Drug-resistant HIV-1 prevalence in patients newly diagnosed with HIV/AIDS in Japan.

The increasing prevalence of drug-resistant HIV transmission has become a critical epidemic in the world today. Studies in developed countries reported 8-27% of newly diagnosed HIV/AIDS patients are infected by drug-resistant strains. To determine the prevalence of drug-resistant HIV-1 among newly diagnosed cases in Japan, eight HIV/AIDS clinical centers, three public health laboratories and the National Institute of Infectious Diseases conducted a nationwide survey. Between January 2003 and December 2004, 575 newly diagnosed HIV/AIDS patients with both acute and chronic infections were enrolled in the study. Twenty-three cases, including three recently infected patients, were infected with HIV-1 having major drug-resistance mutations, including M41L, D67N, L100I, K103N, V106A, M184I, M184V, L210W, and revertant mutations at the 215 codon in reverse transcriptase and M46I in protease encoding regions. In this newly diagnosed population, we also clarified the prevalence of hepatitis virus coinfection, which was 8.8% for HBV and 4.3% for HCV. In conclusion, the drug-resistant transmission rate was 4.0% in Japan. Although this rate is significantly lower than that of other developed countries, this rate almost reaches the threshold at which baseline genotypic resistance testing would be cost-effective for all infected persons before initiating therapy.

[Continuous infusion of coagulant factor concentrates and its pharmacokinetics in patients with hemophilics having low titer inhibitor].

To treat acute episodes of bleeding in patients with hemophilia and low titer inhibitor, "neutralization", which is the neutralization of inhibitors using high dose coagulant factor infusions, is often selected. However, it is difficult to anticipate the dose of continuous infusion (CI) of coagulation products after neutralization. We herein present the CI of coagulant products in 2 patients with hemophilia and low titer inhibitors and discuss the pharmacokinetics of coagulation products. Both patients have had good responses regarding hemostasis using CI after the neutralization. The volume of distribution of coagulation products in case 2 is 3.7 times and clearances of coagulation products are from 2 to 3 times as high as those in patients without inhibitors. It is suspected that the clearances in patients with an inhibitor are higher than those in patients without an inhibitor because a large amount of inhibitor is involved in the extra-vascular space such as tissue fluid and the reticuloendothelial system. The dose for CI of coagulation products after neutralization in patients with inhibitor might be better clarified if the reported cases increase and the pharmacokinetics are more deeply analyzed.

[Exacerbation of acute leukemia bearing isolated i(17q) along with proliferation of blasts with high BMI-1 expression].

We report a case of acute leukemia with an isolated isochromosome 17q karyotypic abnormality, which may be transformed from myeloproliferative disease (MPD)/myelodysplastic syndrome (MDS). A 69-year-old male patient with 27% of blasts in the peripheral blood underwent hematological examinations including cytochemical staining of cells such as myeloperoxydase (MPO), surface marker study on blasts, chromosomal test and bcr-abl mRNA analysis. The cytological and molecular findings (MPO-positive, myeloid marker CD13 expression (67.3%) and megakaryocytic marker CD41 expression (24.8%)) indicated that the blasts were consistent with myeloid leukemic cells partially committed to megakaryocytes. He was diagnosed as having leukemic transformation from MPD/MDS based on history of leukocytosis and thrombocytosis, isolated i(17q), bcr-abl negative, hepatosplenomegaly, increased eosinophil/basophil count and cytologic dysplasia. Positivity of BMI-1 in CD34+ blasts was 25.8% at the diagnosis and anti-leukemic drugs including anthracyclines were effective for his disease control during 6 months. However, the CD34+ cells turned out to highly express BMI-1 (83.1%), and leukemic cells started to increase progressively following which the leukemic cells failed to respond efficiently to any anti-leukemic drugs. Thus, expression of BMI-1 was well correlated with the disease progression, growth ability of blasts and resistance to anti-cancer drugs, indicating that BMI-1 positivity in CD34+blasts is an excellent molecular marker for disease progression and prognosis in such patients.