Purine analog-like properties of bendamustine underlie rapid activation of DNA damage response and synergistic effects with pyrimidine analogues in lymphoid malignancies.

Bendamustine has shown considerable clinical activity against indolent lymphoid malignancies as a single agent or in combination with rituximab, but combination with additional anti-cancer drugs may be required for refractory and/or relapsed cases as well as other intractable tumors. In this study, we attempted to determine suitable anti-cancer drugs to be combined with bendamustine for the treatment of mantle cell lymphoma, diffuse large B-cell lymphoma, aggressive lymphomas and multiple myeloma, all of which are relatively resistant to this drug, and investigated the mechanisms underlying synergism. Isobologram analysis revealed that bendamustine had synergistic effects with alkylating agents (4-hydroperoxy-cyclophosphamide, chlorambucil and melphalan) and pyrimidine analogues (cytosine arabinoside, gemcitabine and decitabine) in HBL-2, B104, Namalwa and U266 cell lines, which represent the above entities respectively.

The novel orally active proteasome inhibitor K-7174 exerts anti-myeloma activity in vitro and in vivo by down-regulating the expression of class I histone deacetylases.

Bortezomib therapy is now indispensable for multiple myeloma, but is associated with patient inconvenience due to intravenous injection and emerging drug resistance. The development of orally active proteasome inhibitors with distinct mechanisms of action is therefore eagerly awaited. Previously, we identified homopiperazine derivatives as a novel class of proteasome inhibitors with a different mode of proteasome binding from bortezomib.

Homopiperazine derivatives as a novel class of proteasome inhibitors with a unique mode of proteasome binding.

The proteasome is a proteolytic machinery that executes the degradation of polyubiquitinated proteins to maintain cellular homeostasis. Proteasome inhibition is a unique and effective way to kill cancer cells because they are sensitive to proteotoxic stress. Indeed, the proteasome inhibitor bortezomib is now indispensable for the treatment of multiple myeloma and other intractable malignancies, but is associated with patient inconvenience due to intravenous injection and emerging drug resistance.

[Clinical analysis of 3 cases with primary splenic diffuse large B-cell lymphoma].

The definition of primary splenic lymphoma is controversial, but it has been reported to be a rare disease that comprises less than 1% of all malignant lymphomas. Three cases of primary splenic diffuse large B-cell lymphoma treated at our institution are described here. Median follow-up was 34.

Histone deacetylases are critical targets of bortezomib-induced cytotoxicity in multiple myeloma.

Bortezomib is now widely used for the treatment of multiple myeloma (MM); however, its action mechanisms are not fully understood. Despite the initial results, recent investigations have indicated that bortezomib does not inactivate nuclear factor-kappaB activity in MM cells, suggesting the presence of other critical pathways leading to cytotoxicity. In this study, we show that histone deacetylases (HDACs) are critical targets of bortezomib, which specifically down-regulated the expression of class I HDACs (HDAC1, HDAC2, and HDAC3) in MM cell lines and primary MM cells at the transcriptional level, accompanied by reciprocal histone hyperacetylation.

The cytotoxic effects of gemtuzumab ozogamicin (mylotarg) in combination with conventional antileukemic agents by isobologram analysis in vitro.

Background: The CD33 antigen is expressed on leukemia cells in most patients with acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL), and in 20% of patients with acute lymphoblastic leukemia (ALL), while it is absent from pluripotent hematopoietic stem cells and nonhematopoietic cells. Gemtuzumab ozogamicin (GO) is an immunoconjugate of an anti-CD33 antibody linked to calicheamicin, which is a potent cytotoxic agent that causes double-strand DNA breaks, resulting in cell death. GO was developed against CD33 antigen-positive leukemias.

Schedule-dependent synergism and antagonism between pemetrexed and docetaxel in human lung cancer cell lines in vitro.

Background: Pemetrexed and docetaxel show clinical activities against a variety of solid tumors including lung cancers. To identify the optimal schedule for combination, cytotoxic interactions between pemetrexed and docetaxel were studied at various schedules using three human lung cancer cell lines A-549, Lu-99, and SBC-5 in vitro.

Methods: Cells were incubated with pemetrexed and docetaxel simultaneously for 24 or 120 h.

Long-term results of dose-intensive chemotherapy with G-CSF support (TCC-NHL-91) for advanced intermediate-grade non-Hodgkin's lymphoma: a review of 59 consecutive cases treated at a single institute.

We evaluated the long-term outcome of very dose-intensive chemotherapy (TCC-NHL-91) for advanced intermediate-grade lymphoma, in which an eight-cycle regimen with 11 drugs was given with granulocyte colony-stimulating factor (G-CSF) support (total 18 weeks). Fifty-nine patients were treated during February 1, 1991 and March 31, 2001 (median age: 48 years). Forty-three patients (73%) were in a high-intermediate risk or high-risk group (HI/H) according to the age-adjusted International Prognostic Index (aa-IPI).

[MTX-HOPE (methotrexate, hydrocortisone, vincristine, sobuzoxane, and etoposide) as a low-dose salvage chemotherapy for recurrent or refractory non-Hodgkin's lymphoma].

We conducted a clinical study of MTX-HOPE (day 1, methotrexate 20 mg per os (po); day 2, hydrocortisone 100 mg intravenous (iv), vincristine 1 mg iv; day 3,4 sobuzoxane 400 mg po; etoposide 25 mg po, repeating every 2 or 3 weeks) in 14 relapsed or refractory patients with non-Hodgkin's lymphoma. Ten responders were obtained 5 CR and 5 PR), and heavily treated patients were included in the responders. The median duration of over all survival which was estimated with Kaplan-Meier curve was 11.

Schedule-dependent interactions between pemetrexed and cisplatin in human carcinoma cell lines in vitro.

The combination of pemetrexed and cisplatin shows good clinical activity against mesothelioma and lung cancer. In order to study the potential cellular basis for this, and provide leads as to how to optimize the combination, we studied the schedule-dependent cytotoxic effects of pemetrexed and cisplatin against four human cancer cell lines in vitro. Tumor cells were incubated with pemetrexed and cisplatin for 24 h at various schedules.

Cytotoxic effects of histone deacetylase inhibitor FK228 (depsipeptide, formally named FR901228) in combination with conventional anti-leukemia/lymphoma agents against human leukemia/lymphoma cell lines.

FK228 is a novel antitumor depsipeptide that inhibits histone deacetylases and restores the expression of genes aberrantly suppressed in cancer cells. This agent was shown to have broad antitumor activity in preclinical studies, and is currently under phase I/II evaluations. Because of its wide spectrum of actions, it is reasonable to consider the combination with other anticancer drugs in clinical application.

Gene Expression Profiles of CD133-positive Fractions Predict the Survival of Individuals with Acute Myeloid Leukemia.

Background: The current classification of acute myeloid leukemia (AML) is based predominantly on the cytogenetic abnormalities and morphology of the malignant blasts and is not always helpful for optimization of the treatment strategy. Gene expression profiles of AML blasts were obtained and a gene expression-based means of predicting the outcome of AML patients was developed.

Materials And Methods: CD133-positive hematopoietic stem cell-like fractions were purified from the bone marrow of 99 individuals with AML-related disorders and the expression profiles of ~33,000 human transcripts in these cells were characterized with the use of DNA microarray analysis.

Schedule-dependent synergism and antagonism between pemetrexed and paclitaxel in human carcinoma cell lines in vitro.

Pemetrexed is a novel multitargeted antifolate with significant clinical activity against a variety of tumors. We studied the schedule-dependent cytotoxic effects of pemetrexed in combination with paclitaxel in vitro to improve our understanding of how this combination might be used clinically. Human lung cancer A549 cells, breast cancer MCF7, ovarian cancer PA1, and colon cancer WiDr cells were exposed to both pemetrexed and paclitaxel in vitro.