Activation of the leukemia plasmacytoid dendritic cell line PMDC05 by Toho-1, a novel IDO inhibitor.

Background/aim: Indoleamine-2,3-dioxygenase (IDO) is a rate-limiting enzyme for tryptophan metabolism and plays an immunosuppressive role. Antigen-presenting cells, when activated, increase the expression of IDO, which results in the suppression of subsequent immune reaction. A novel IDO inhibitor, Toho-1, was explored for its applicability to immunotherapy.

Induction of apoptosis of leukemic cells by TRUE gene silencing using small guide RNAs targeting the WT1 mRNA.

TRUE gene silencing is a technology to eliminate specific cellular RNAs by using tRNase Z(L) and small guide RNA (sgRNA). Here we investigated how WT1-mRNA-targeting sgRNAs affect leukemic cells. We showed that sgRNA can be easily taken up by cells without any transfection reagents, and that the naked sgRNAs targeting the WT1 mRNA can reduce its mRNA levels and WT1 protein amounts in the WT1-expressing leukemic cells.

Quantification of BCR-ABL mRNA in plasma/serum of patients with chronic myelogenous leukemia.

Quantification of tumor-associated mRNA extracted from blood cells/tissues containing tumor cells is used for evaluation of treatment efficacy or residual tumor cell burden in tumors including leukemia. However, this method using tumor cell-containing blood/tissue is difficult to evaluate the whole tumor cell burden in the body. In order to establish an efficient method to evaluate the whole tumor cell burden in the body, we tried to quantify tumor-associated mRNA existing in plasma/serum instead of leukemia cell-containing blood cells in patients with chronic myelogenous leukemia (CML) and compared the levels of BCR-ABL mRNA between plasma/serum and peripheral blood cells.

Direct effect of dasatinib on proliferation and cytotoxicity of natural killer cells in in vitro study.

Lymphocytosis predominantly due to natural killer (NK) cells has been reported in nearly a half of chronic myelogenous leukemia (CML) patients who were being treated with dasatinib. Besides, dasatinib-treated patients with lymphocytosis have a better prognosis than patients without lymphocytosis. In order to elucidate the effects of dasatinib on the proliferation of lymphocyte subset, dasatinib was added to the culture of peripheral blood mononuclear cells with IL-2 (lymphokine-activated killer culture) or a low dose of IL-2 with zoledronate (γδ T-cell culture).

Enhancement of antigen presenting ability in the leukemic plasmacytoid dendritic cell line (PMDC05) by lentiviral vector-mediated transduction of CD80 gene.

PMDC05, a leukemic plasmacytoid dendritic cell (pDC) line which was established in our laboratory, showed a capacity of generating antigen-specific cytotoxic T lymphocytes (CTLs). In order to enhance an antigen presenting ability of PMDC05, PMDC05 was transduced with CD80 gene by lentiviral vector, which was named as PMDC11. PMDC11 displayed a strong antigen presenting ability even without any stimulation, and by culturing with stimulators such as calcium ionophore PMDC11 gained a more potent antigen presenting ability.

Alteration of POLDIP3 splicing associated with loss of function of TDP-43 in tissues affected with ALS.

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease caused by selective loss of motor neurons. In the ALS motor neurons, TAR DNA-binding protein of 43 kDa (TDP-43) is dislocated from the nucleus to cytoplasm and forms inclusions, suggesting that loss of a nuclear function of TDP-43 may underlie the pathogenesis of ALS. TDP-43 functions in RNA metabolism include regulation of transcription, mRNA stability, and alternative splicing of pre-mRNA.

Generation of antigen-specific cytotoxic T lymphocytes using a leukemic plasmacytoid dendritic cell line as antigen presenting cells.

Establishment of a leukemia plasmacytoid dendritic cell line (PMDC05) and intra-lineage transformation from pDCs to mDCs in PMDC05 has been reported. In this paper, we show the applicability of PMDC05 for cellular immunotherapy. By stimulation with LPS, PMDC05 showed enhancement in expression of antigen presentation-associated surface molecules and production of cytokines (IL-12p70 and TNF-α).

Transformation of dendritic cells from plasmacytoid to myeloid in a leukemic plasmacytoid dendritic cell line (PMDC05).

We investigated the transformation from pDCs to mDCs in a pDC line (PMDC05) which was established from a patient with pDC leukemia in our laboratory. PMDC05 cells were separated into two fractions according to the expression of BDCA1 and CD123. BDCA1(-)CD123(+) cells were found to be pDC-like cells by their morphology, surface phenotypes, mRNA expression and the function.

WT1 peptide vaccination in a CML patient: induction of effective cytotoxic T lymphocytes and significance of peptide administration interval.

Although antigen-specific immune responses including cytotoxic T cells (CTLs) against antigen peptide could be enhanced after tumor antigen peptide vaccinations, the immune responses do not necessarily result in a decrease or eradication of tumor cells in the vaccination trials. We focused on whether antigen-specific CTLs could be damaged by the repeated stimulation of antigenic peptide and whether regulatory T (Treg) cells would be increased by the administration of WT1 peptide. We administered WT1 peptide 22 times over 18 months in a CML patient who was being treated with imatinib.

A leukemic plasmacytoid dendritic cell line, PMDC05, with the ability to secrete IFN-alpha by stimulation via Toll-like receptors and present antigens to naïve T cells.

We established a plasmacytoid dendritic cell (pDC) line (PMDC05) from leukemia cells of pDC leukemia. PMDC05 cells were positive for CD4, CD56, CD33, HLA-DR, CD123 (IL-3Ralpha) and CD86 in the absence of lineage markers. mRNA of TLR1, TLR2, TLR4, TLR7 and TLR9 was clearly expressed and among these TLRs, TLR7 was prominent.

Induction of antigen-specific cytotoxic T lymphocytes by using monocyte-derived DCs transfected with in vitro-transcribed WT1 or SART1 mRNA.

To evaluate the usefulness of monocyte-derived dendritic cells transfected with tumor antigen mRNA for dendritic cell-based antitumor immunotherapy, we attempted to generate antigen-specific cytotoxic T cells by priming lymphocytes with monocyte-derived dendritic cells transfected with in vitro-transcribed tumor antigen mRNA. Mature monocyte-derived dendritic cells were generated from microbeads-separated CD14(+) cells by culturing with GM-CSF/IL-4 for 7 days and with TNF-alpha, IL-1alpha, IL-6, and PGE(2) for the last one day. Monocyte-derived dendritic cells, lymphocytes, and target cells, which were positive for HLA-A24, were used in the present study.