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Masayuki Sano

Publications and source records attributed to Masayuki Sano.

12 recordsLinked to original sources
PubMed2006

Sequence-specific interference by small RNAs derived from adenovirus VAI RNA.

A virus-associated RNA (VAI) of adenoviruses is a cytoplasmic non-coding RNA and it plays an important role for viral replication in infected cells. VAI RNA transcripts, produced by RNA polymerase III (pol III), form tightly structured stems, which confer resistance to cellular defense systems. We demonstrate here that small RNAs of approximately 22 nucleotides are produced from a terminal stem region but not from an apical stem of VAI RNA. We determined the processing sites of VAI RNA by S1 nuclease mapping and further confirmed that the processed small RNA can act as small interfering RNAs (siRNAs) or as microRNAs (miRNAs) in transient transfection assays and during viral infection. Our data demonstrate that non-coding RNAs synthesized by pol III can be substrates for Dicer, and diced small RNAs might regulate cellular phenomena as siRNAs and miRNAs.

Adenoviridae↗
PubMed2006

A phase II study of VEPA/FEPP chemotherapy for aggressive lymphoma in elderly patients: Japan Clinical Oncology Group Study JCOG9203.

The Lymphoma Study Group (LSG) of the Japan Clinical Oncology Group conducted a phase II trial of LSG12 therapy for 45 elderly patients with aggressive lymphoma to clarify whether LSG12 reduces severe infection without lowering the complete response (CR) rate in comparison with LSG4. LSG12, which consisted of a regimen of vincristine, cyclophosphamide, prednisolone, doxorubicin, vindesine, etoposide, and procarbazine (VEPA/FEPP), excluded bleomycin and methotrexate of LSG4 therapy, reduced the dosages of doxorubicin and cyclophosphamide, and increased etoposide and procarbazine dosages instead. Inclusion criteria consisted of a patient age of 70 to 75 years, a World Health Organization performance status of 0 to 2, and acceptable organ function. The treatment was completed in 47% of the patients and terminated early for disease progression in 20% and for toxicity in 16%. The CR rate was 60% (95% confidence interval [CI], 44%-74%). The 5-year overall survival (OS) rate was 42% (95% CI, 27%-57%), and the median OS time was 4.3 years. Leukopenia of grade 3 to 4 occurred in 98% of the patients, and severe infection occurred in 9%. Eight patients with hepatitis C virus (HCV) antibody showed no severe hepatic toxicity and had a better CR or OS rate than the 37 HCV-negative patients. Although the outcomes of LSG12 met our expectations with a reduction in severe infection and equivalent CR and OS outcomes compared with LSG4 and CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone), the possibility of a regimen more beneficial than LSG12 for aggressive lymphoma in the elderly patient should be explored because of frequent hematologic toxicity and poor compliance in LSG12.

Aged↗
PubMed2005

Novel methods for expressing RNA interference in human cells.

RNA interference (RNAi) is a conserved process in which a double-stranded RNA (dsRNA) induces sequence-specific gene silencing. Recent developments in the use of the 21-nt small interfering RNA (siRNA) have allowed the specific degradation of mRNA without induction of nonspecific effects in mammalian cells. RNAi provides a method for knocking down genes of interest and a powerful tool for studies on gene functions in various organisms. Although many vector-based siRNA expression systems have been developed for production of siRNAs in mammalian cells, many technical issues for an effective production of siRNAs still need to be resolved. In this chapter, we describe methods for construction of genetically stable and highly active siRNA expression systems and also mention some strategies to overcome serious technical problems.

Base Sequence↗
PubMed2004

Ribozymes: applications to functional analysis and gene discovery.

Ribozymes are catalytic RNA molecules that cleave RNAs with high specificity. Since the discovery of these non-protein enzymes, the rapidly developing field of ribozymes has been of particular interest because of the potential utility of ribozymes as tools for reversed genetics. However, despite extensive efforts, the activity of ribozymes in vivo has not usually been high enough to achieve the desirable biological effects. Now, by the use of RNA polymerase III (pol III) promoters, the ribozyme activity in cells has been successfully improved by developing efficient transport systems for the transcripts to the cytoplasm. In addition, it is possible to cleave a specific target RNA in cells by using an allosterically controllable ribozyme or an RNA-protein hybrid ribozyme. These ribozymes are potentially applicable to molecular gene therapy and efficient gene discovery systems. Furthermore, the developed pol III expression system is applicable to the expression of small interfering RNAs (siRNAs). The advantage of such ribozymes over siRNAs is the high specificity of the ribozyme that would not cause interferon responses.

Allosteric Site↗
PubMed2004

Ribozyme expression systems.

We have succeeded in constructing an effective system for the expression of ribozymes under the control of a human tRNAVal promoter, which ensures a high level of production of ribozymes in vivo. The engineered tRNAVal-driven ribozymes, based on computer-predicted secondary structure, were relatively stable and were transported to the cytoplasm, where they could be colocalized with their target RNA. The activity of the exported ribozymes was significantly higher than that of ribozymes that remained in the nucleus. This chapter examines the methods for construction of the appropriate vector that can produce tRNA-driven ribozymes with high-level intracellular activity and for analysis of the constructs in cells.

Base Sequence↗
PubMed2004

Phase III study of ranimustine, cyclophosphamide, vincristine, melphalan, and prednisolone (MCNU-COP/MP) versus modified COP/MP in multiple myeloma: a Japan clinical oncology group study, JCOG 9301.

To investigate whether combination chemotherapy with vincristine, cyclophosphamide, prednisolone, and melphalan (COP/ MP) with the addition of ranimustine (MCNU) (MCNU-COP/MP) is superior to the slightly modified COP/MP (mCOP/MP) regimen in multiple myeloma (MM), a multicenter randomized study was performed. Two hundred ten patients with newly diagnosed, overt MM not treated with chemotherapy were enrolled from 32 institutions of the Lymphoma Study Group of the Japan Clinical Oncology Group and were randomized to receive either MCNU-COP/MP or mCOP/MP. The response rate (RR) to mCOP/MP was 43.7% (95% confidence interval [CI], 33.9%-53.8%] and to MCNU-COP/MP was 56.1% (95% CI, 46.1%-65.7%) (P = .097). The progression-free survival (PFS) was significantly longer for patients treated with MCNU-COP/MP than for patients treated with mCOP/MP (median, 23.0 months [95% CI, 18.9-25.8] versus 15.8 months [95% CI, 14.1-19.4]) (P = .014). However, no significant difference in overall survival rate (OS) was observed between the groups (median, 49.9 months [95% CI, 40.4-59.1] versus 44.0 months [95%, CI, 32.8-59.8]) (P = .75). Grades 3 and 4 hematological toxicities were more frequently observed with MCNU-COP/MP than with mCOP/MP, but the incidence of grades 3 and 4 nonhematological toxicities was low in both groups. In conclusion, MCNU-COP/MP in comparison with mCOP/MP improved RR and PFS in overt MM; however, this outcome did not contribute to prolonging OS, indicating that addition of MCNU to mCOP/MP has no benefit on survival.

Adult↗
PubMed2004

A randomized controlled trial investigating the survival benefit of dose-intensified multidrug combination chemotherapy (LSG9) for intermediate- or high-grade non-Hodgkin's lymphoma: Japan Clinical Oncology Group Study 9002.

The effect of enhancing the dose intensity (DI) of the key drugs in multidrug combination chemotherapy for malignant lymphoma is uncertain. We investigated the survival benefit of dose-intensified multidrug combination chemotherapy for intermediate- or high-grade non-Hodgkin's lymphoma (NHL). Patients without any prior chemotherapy were randomly assigned either to dose-intensified multidrug combination chemotherapy, LSG9 (VEPA-B/FEPP-AB/M-FEPA, treated 3 times every 10 weeks for 28 weeks total), or to control-arm combination chemotherapy, mLSG4 (VEPA-B/FEPP-B/M-FEPA, treated 4 times every 14 weeks for 54 weeks total). The planned DI of doxorubicin and cyclophosphamide were 1.96 and 1.47 times higher, respectively, in LSG9 than in mLSG4. Overall survival, complete response (CR) rate, and toxicities were evaluated. The 447 patients (230 for LSG9 and 217 for mLSG4) were enrolled between February 1991 and March 1995. The 5-year overall survival rates were 56.8% for LSG9 patients and 55.1% for mLSG4 patients (log-rank P = .42). The rates for CR plus uncertain CR were 70.0% for LSG9 and 64.5% for mLSG4. The toxicities of both regimens were similar and tolerable. The median actual DI of doxorubicin and cyclophosphamide were 1.56 and 1.17 times higher, respectively, in LSG9 than in mLSG4. Compared with the control regimen mLSG4, the dose-intensified regimen LSG9 did not show significant survival benefit. An increase in the DI of doxorubicin in multidrug combination chemotherapy did not improve the survival of patients with intermediate- or high-grade NHL.

Adolescent↗
PubMed2004

[Fatal opportunistic infection following disappearance of antibodies by immunosuppressive therapy in a patient with acquired factor VIII inhibitor].

An 83-year-old man without history of the hemorrhagic diathesis was admitted to our hospital with a 4-months history of purpura and subcutaneous hematoma. He had an extraordinarily prolonged activated partial thromboplastin time, and his factor VIII (F VIII) activity level was 0.2%. A study revealed the existence of an IgG type anti-F VIII inhibitor at a titer of 1004 Bethesda units/ml. He received recombinant factor VIIa and immunosuppressive therapy with cyclophosphamide, prednisolone and cyclosporin, but despite this the titer of F VIII inhibitor remained high. Although the inhibitor disappeared after methylprednisolone mini-pulse therapy, the patient died of opportunistic infections with cytomegalovirus and pneumocystis carinii. The majority of patients with acquired F VIII inhibitor belong to the elderly population, and the standard therapeutic strategy to eliminate the acquired F VIII inhibitor has not been established. Those patients with high titers of F VIII inhibitor require particularly long term immunosuppressive therapy. Therefore, it is important to bear in mind treatment-related opportunistic infections in a case with a high titer of acquired F VIII inhibitor.

Aged↗
PubMed2003

Analysis of processing-defective variants of human tRNA(Val).

Eukaryotic tRNAs are transcribed, processed and exported from the nucleus to the cytoplasm to participate in protein biosynthesis. A variant of human gene for tRNA(Val), HtV4, is not processed neither its 5'- nor its 3'-flanking sequences. By RT-PCR analysis and in situ hybridization, we demonstrated that the HtV4 was constitutively expressed without processing, and localized in the nucleus in HeLa cells.

Base Sequence↗
PubMed2002

Novel method for selection of tRNA-driven ribozymes with enhanced stability in mammalian cells.

Intracellular stability is a critical determinant of the activity of a ribozyme in vivo. In previous studies, we succeeded in constructing an effective system for the expression of ribozymes using the promoter of a human gene for tRNA(Val). The resultant tRNA(Val)-driven ribozymes (tRNA-ribozymes) had a half-life of approximately 100 minutes. In the present study, we established a novel system for the selection of tRNA-ribozymes that were more stable than a previously generated optimally designed tRNA-ribozyme, and we confirmed that the newly selected tRNA-ribozymes worked well. Selective pressure was applied by treating cells that expressed tRNA-ribozymes with actinomycin D, and the system yielded tRNA-ribozymes with enhanced stability. The sequences isolated after selection exhibited some similarities. Furthermore, some selected tRNA-ribozymes had almost the same activity as or higher activity than that of the optimally designed tRNA-ribozyme despite the fact that the selective pressure was not aimed at enhancing the cleavage activity. Our approach might be very useful for selection not only of ribozymes with enhanced stability but also of other functional nucleic acids in vivo.

Base Sequence↗
PubMed2002

Acute myelogenous leukemia following treatment with cyclosporin A in a nephrotic patient.

We report here a very rare case of a nephrotic patient who developed acute myelogenous leukemia (AML, M2) 8 months after receiving cyclosporin A (CsA) therapy. A 30-year-old man with nephrotic syndrome had been taking diphenylhydantoin (DPH, 300 mg/day) for 6 years for treatment of convulsion and then received treatment of prednisolone and CsA (75 mg/day) for a nephrotic syndrome. Approximately 4 months after CsA therapy began, myeloblasts appeared in his peripheral blood at a ratio of 1%. Four months later, bone marrow aspiration and a biopsy confirmed a diagnosis of AML M2, showing hypercellular bone marrow with 60% leukemic cells. He received induction chemotherapy, which led to a complete remission.

Adult↗