tretinoin and Lymphoma--T-Cell

In view of the importance of vitamin A in the human immune system and the central role of interleukin-2 (IL-2) in the proliferation of T-lymphocytes, we examined the effects of all-trans-retinoic acid (ATRA) on the protein and gene expression of IL-2 in the human T-cell line HUT-78 when stimulated with either 12-O-tetradecanoylphorbol-13-acetate (TPA) or phytohemagglutinin (PHA). ATRA enhanced the production of IL-2 stimulated by TPA, but suppressed that stimulated by PHA. These findings were consistent with the results of a reverse transcription-polymerase chain reaction and quantitative real-time polymerase chain reaction examining IL-2 gene expression. ATRA augmented the gene expression of PKC-beta1 up-regulated by TPA and restored that suppressed by PHA but to below the control level. ATRA suppressed the c-fos gene expression up-regulated by PHA to a level of 36% of the control whereas it had no effect on the up-regulation by TPA. Since PKC- beta1 has been suggested to be important for the secretion and gene expression of IL-2 and since the activator protein-l binding site is present in the promoter of the IL-2 gene, these findings may explain the differences in ATRA's effects on TPA- and PHA-stimulated IL-2 expression. These results suggest that ATRA affects the production of IL-2 by T-lymphocytes in a stimulus-dependent manner.

Topics: Cell Line, Tumor; Cell Proliferation; Enzyme-Linked Immunosorbent Assay; Gene Expression Regulation, Neoplastic; Genes, fos; Humans; Interleukin-2; Lymphoma, T-Cell; Phytohemagglutinins; Protein Kinase C; Receptors, Interleukin-2; Reverse Transcriptase Polymerase Chain Reaction; Tetradecanoylphorbol Acetate; Tretinoin

We have investigated the primary immunity generated in vivo by MHC class I-deficient and -competent tumor cell lines that expressed the NKG2D ligand retinoic acid early inducible-1 (Rae-1) beta. Rae-1beta expression on class I-deficient RMA-S lymphoma cells enhanced primary NK cell-mediated tumor rejection in vivo, whereas RMA-Rae-1beta tumor cells were rejected by a combination of NK cells and CD8(+) T cells. Rae-1beta expression stimulated NK cell cytotoxicity and IFN-gamma secretion in vitro, but not proliferation. Surprisingly, only NK cell perforin-mediated cytotoxicity, but not production of IFN-gamma, was critical for the rejection of Rae-1beta-expressing tumor cells in vivo. This distinct requirement for perforin activity contrasts with the NK cell-mediated rejection of MHC class I-deficient RMA-S tumor cells expressing other activating ligands such as CD70 and CD80. Thus, these results indicated that NKG2D acted as a natural cytotoxicity receptor to stimulate perforin-mediated elimination of ligand-expressing tumor cells.

Topics: Animals; Cell Death; Cells, Cultured; Cytotoxicity, Immunologic; Graft Rejection; Interferon-gamma; Killer Cells, Natural; Ligands; Lymphocyte Activation; Lymphoma, T-Cell; Membrane Glycoproteins; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; NK Cell Lectin-Like Receptor Subfamily K; Perforin; Pore Forming Cytotoxic Proteins; Receptors, Immunologic; Receptors, Natural Killer Cell; Tretinoin; Tumor Cells, Cultured

The rat Nb2 lymphoma is useful for studying prolactin (PRL) receptor signaling to mitogenesis and apoptosis suppression. Previous results showed that PRL rapidly induced expression of several apoptosis suppressor genes during the G1 phase of cell cycle in this model. The X-linked inhibitor of apoptosis protein (XIAP) gene product acts to suppress apoptosis by direct inhibition of caspases. The present study was conducted to determine whether PRL alters XIAP expression in lactogen-dependent Nb2-11 or -independent Nb2-SFJCD1 cells. Stationary Nb2-11 cultures expressed detectable levels of an 8.9-kb XIAP transcript. PRL (20 ng/mL) stimulated its expression, reaching maximal levels within 12 h. Expression of XIAP was also evaluated in Nb2-SFJCD1 cells subsequent to treatment with differentiating agents (sodium butyrate [2 mM, 72 h], all trans-retinoic acid [10 microM, 72 h], or 1,25-dihydroxycholecalciferol [100 nM, 24 h]). PRL significantly increased XIAP expression in cells previously treated with these compounds. Further analysis revealed that PRL stimulated XIAP expression during S phase of the cell cycle. To determine whether XIAP suppressed apoptosis, its cDNA was stably transfected into Nb2-11 cells. Compared to controls, cells overexpressing XIAP exhibited substantially less DNA fragmentation when apoptosis was induced by PRL deprivation or glucocorticoids. We conclude that PRL-stimulated XIAP expression likely serves to suppress apoptosis as cells progress through the later phases of the cell cycle.

Topics: Animals; Butyrates; Calcitriol; Cell Differentiation; Dexamethasone; DNA Fragmentation; Gene Expression; Glucocorticoids; Lymphoma, T-Cell; Prolactin; Proteins; Rats; RNA, Messenger; S Phase; Sheep; Transfection; Tretinoin; Tumor Cells, Cultured; X-Linked Inhibitor of Apoptosis Protein

Retinoic acid (RA) has been used to induce the regression of refractory T-cell lymphoma. In vitro and in vivo studies have shown that RA exerts this effect through the induction of apoptosis. This study was designed to investigate the molecular pathway of RA-induced apoptosis in T-lymphoma cell lines.RA-induced apoptosis was verified by morphology, flow cytometry, and DNA ladder analysis. Differential display method using a combination of 12 poly(A)-anchored primers and 20 arbitrary primers was adopted for gene cloning. Total RNAs were extracted from H9 cell line at 0, 6, 12, and 24 hours after All-trans RA (ATRA) treatment and the serial expression patterns of the candidate fragments were recognized. The cloned gene fragments were then analyzed and confirmed by Northern blot analysis on H9 and SR786 cell lines.ATRA-induced apoptosis of T-cell lymphoma was protein synthesis-dependent. The execution or irreversible phase of apoptosis appeared to occur at 6-12 hours of RA treatment. Among the 60,000 arbitrarily displayed bands, 25 of 250 candidate fragments were selected for further cloning and sequencing. A total of 14 clones could be matched to known genes and were categorized into four groups: A) transcription factors: prothymosin, CA150, p78 serine/threonine kinase, IL-1beta-stimulating gene, glucocorticoid receptor, MLN64/CAB1, gastrin-binding protein, and polypeptide from glioblastoma; B) chaperone: 90 kDa heat shock protein; C) ion channel: chloride channel protein 3; and D) cytoskeleton: cytovillin2/ezrin and vimentin. Another two clones of genes were of unrecognized functions. The remaining 11 clones belonged to unmatched or novel genes. The expression of these genes varied, either upregulated or downregulated, in response to ATRA treatment.RA-induced apoptosis may involve a cascade of genes that are related to transcription regulation, stress response, housekeeping, and the execution of apoptosis. The clarification of the RA-induced apoptotic pathway will help us to understand the molecular mechanism of cancer differentiation agents.

Topics: Apoptosis; Blotting, Northern; Chloride Channels; Cloning, Molecular; Cytoskeletal Proteins; DNA; DNA Fragmentation; Flow Cytometry; HSP90 Heat-Shock Proteins; Humans; Kinetics; Lymphoma, T-Cell; Phosphoproteins; Polymerase Chain Reaction; Sequence Alignment; Sequence Analysis, DNA; Transcription Factors; Tretinoin; Tumor Cells, Cultured; Vimentin

We demonstrate that N-(4-hydroxyphenyl)-all-trans-retinamide (4-HPR), a synthetic retinoic acid (RA) derivative, is a potent and selective inducer of apoptosis in malignant T lymphoid cells, but has little effect on normal lymphoid cells of the thymus or spleen. 4-HPR and its stereoisomer, 9-cis-4-HPR, are 50 to > 150 times more potent than 7 other retinoids in killing CEM-C7 human T lymphoblastoid leukemia cells and P1798-C7 murine T lymphoma cells. 4-HPR's apoptotic action requires the intact molecule bearing both the retinoid moiety and the hydroxyphenol ring; 4-HPR remains unmetabolized after uptake into CEM-C7 and P1798-C7 cells for up to 24 hours. We also show that glucocorticoid (GC)-resistant variants are equally susceptible to 4-HPR as are GC-sensitive cells. Thus, 4-HPR may be potentially important as a new chemotherapeutic drug for use as alternative to, or in combination with, conventional drugs for treating lymphoid malignancies.

Topics: Aminophenols; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Division; Cells, Cultured; DNA Fragmentation; Drug Resistance, Neoplasm; Fenretinide; Glucocorticoids; Humans; Leukemia, T-Cell; Lymphocytes; Lymphoma, T-Cell; Mice; Mice, Inbred BALB C; Retinoids; Spleen; Stereoisomerism; Thymus Gland; Tretinoin; Tumor Cells, Cultured