Mitsuru Itoh

Ceramide Reduction and Transcriptional Up-Regulation of Glucosylceramide Synthase through Doxorubicin-Activated Sp1 in Drug-Resistant HL-60/ADR Cells

Treatment with doxorubicin (DOX) induced apoptosis with an increase of ceramide content in drug-sensitive HL-60 cells, but not in drug-resistant HL-60/ADR cells. In HL-60/ADR cells (but not in HL-60 cells), the levels of mRNA, protein, and activity in glucosylceramide synthase (GCS), which converts ceramide to glucosylceramide, were up-regulated in response to DOX. Thus, abrogation of apoptosis in HL-60/ADR cells might be involved in ceramide reduction through DOX-induced up-regulation of GCS function. Because we reported that a GC-rich/Sp1 promoter binding region was of importance in the regulation of GCS expression, the role of Sp1 in DOX-induced up-regulation of GCS and apoptosis was investigated. DOX induced Sp1 activation in HL-60/ADR cells, as assessed by Sp1 gel shift and promoter-luciferase reporter assays, whereas transfection of double-stranded oligodeoxynucleotides (ODNs) containing a GC-rich/Sp1 region (Sp1 decoy ODNs) inhibited DOX-induced Sp1 activation. In addition, DOX-increased mRNA and enzyme activity in GCS were inhibited by Sp1 decoy, in conjunction with corresponding elevations of ceramide content. Moreover, DOX-induced apoptotic cell death was significantly increased in Sp1 decoy ODN-transfected HL-60/ADR cells over mock-transfected HL-60/ADR cells. Together, the results suggest that transcriptional up-regulation of GCS through DOX-induced activation of Sp1 is one potential mechanism to regulate ceramide increase and apoptosis in HL-60/ADR cells.

Acute myeloid leukemia with t(5;11): two case reports

A case of acute monocytic leukemia (AMoL) with t(5;11)(q31;q23) and a case of acute myelomonocytic leukemia (AMMoL) with t(5;11)(q35;q13.1) are reported. The translocation between the long arm of chromosome 11q and that of chromosome 5q with leukemia have been rarely reported. Though breakpoint of both cases were subtlety different, they had morphologically monocytic character and showed hyperleukocytosis and chemoresistance.

Substantial Improvement in a Nerve Conduction Study of Lymphoma-associated Demyelinating Neuropathy Treated by Intravenous Immunoglobulin and Chemotherapy

A 64-year-old woman with lymphoma-associated demyelinating neuropathy was treated by 6 cycles of R-CHOP with intravenous immunoglobulin in the first 2 cycles. We noted substantial improvement in the findings of a nerve conduction study (NCS) after the first cycle, followed by more protracted improvement during the second to sixth cycles. The improvement of the neurological symptoms paralleled the findings of the NCS. Our case provides important information for understanding the etiology and optimization of treatments for lymphoma-associated demyelinating neuropathy.

Successful engraftment after cord blood transplantation from an HLA-homozygous donor (homo-to-hetero cord blood transplantation) in a primary myelofibrosis patient with broad HLA antibodies: Successful engraftment after CBT from an HLA

Donor‐specific human leukocyte antigen (HLA) antibodies are a significant risk factor for graft failure in cord blood transplantation (CBT). Although there are several treatments to decrease HLA antibodies, such as platelet transfusion, plasma exchange, rituximab, and bortezomib, their effectiveness has not been established.