tretinoin and Leukemia--T-Cell

We previously reported that all-trans retinoic acid (ATRA) inhibits growth in human T-cell leukemia virus type 1 (HTLV-1)-positive T-cell lines and fresh cells from patients with adult T-cell leukemia. However, the mechanism of this inhibition is not clear. In the present study, we observed that NF-kappaB transcriptional activity as well as cell growth decreased significantly in HTLV-1-positive T-cell lines in the presence of ATRA. Furthermore, we observed that ATRA reduced HTLV-1 proviral DNA, HTLV-1 genes (gag, tax, or pol mRNA) using the real-time quantitative polymerase chain reaction. SIL-2R was reduced by ATRA in both protein level (culture supernantant) and mRNA level in HTLV-1-positive T-cell lines. Interestingly, ATRA significantly inhibited RT activity similar to azidothimidine (AZT) in HTLV-1-positive T-cell lines. Moreover, AZT inhibited proviral DNA but not NF-kappaB transcriptional activity, and sIL-2R on HTLV-1; however, ATRA inhibited of NF-kappaB, proviral DNA and sIL-2R on HTLV-1. These results suggested that the decrease in sIL-2R induced by ATRA may be caused by the actions of a NF-kappaB inhibitor acting on the NF-kappaB/sIL-2R signal pathway. These results suggested that ATRA could have two roles, as a NF-kappaB inhibitor and as an RT inhibitor.

Topics: Adult; Antineoplastic Agents; Cell Division; Deltaretrovirus Infections; Gene Expression Regulation, Leukemic; Gene Expression Regulation, Viral; Gene Products, gag; Gene Products, pol; Genes, pX; Human T-lymphotropic virus 1; Humans; In Vitro Techniques; Jurkat Cells; Leukemia, T-Cell; NF-kappa B; Proviruses; Receptors, Interleukin-2; Signal Transduction; Solubility; Transcriptional Activation; Tretinoin; Viral Load

Adult T-cell leukemia (ATL) is a peripheral T-cell neoplasm caused by human T-cell leukemia virus type I (HTLV-I). We previously reported that retinoic acid (RA) isomers, all-trans-RA (ATRA), 9-cis-RA and 13-cis-RA, induce growth arrest and apoptosis in ATL cell lines. In this study we investigate the mechanisms of apoptosis induced by RAs.. An ATL cell line, KK1, established from an ATL patient was cultured with or without RAs. DNA fragmentation was analyzed using propidium iodide for staining DNA on a FACS. The apoptosis-related proteins and their transcriptional levels were thereafter analyzed by Western blotting and reverse transcription polymerase chain reaction (RT-PCR). Caspase activity was determined by using specific fluorogenic substrates.. Bcl-2 and Bcl-xL are constitutively expressed in KK1. Treatment with RAs caused the level of Bcl-x protein decreased, while the levels of Bcl-2 and Bcl-xS remained unchanged. The level of Bax tended to decrease. There was a reduction of mitochondrial membrane potential and activation of caspase-3 and -6 without any activation of caspase-1. Broad range caspase inhibitors, Z-Asp and Z-VAD, prevented DNA fragmentation.. These results suggest that the RA-induced apoptotic signals were transduced via downregulation of Bcl-xL and the decrease in the mitochondrial membrane function leading to caspase-3 activation.

Topics: Adult; Apoptosis; bcl-X Protein; Caspase 3; Caspase 6; Caspases; Cell Line, Tumor; DNA Fragmentation; Down-Regulation; Enzyme Activation; Humans; Leukemia, T-Cell; Membrane Potentials; Mitochondria; Proto-Oncogene Proteins c-bcl-2; RNA, Messenger; Tretinoin

We report a case in which treatment with all-trans-retinoic acid (ATRA) improved the clinical features of a 47-year-old female patient with acute adult T-cell leukemia (ATL). The patient was first treated several times with combination chemotherapy. but the number of ATL cells increased and other clinical manifestations progressed. ATRA 60 mg was then administered daily. ATRA treatment dramatically improved the patient's clinical features. In vitro examination revealed that ATRA inhibited the growth of ATL cells from the patient. These findings suggest that ATRA may be a useful treatment for patients with chemotherapy-resistant acute ATL.

Topics: Acute Disease; Antineoplastic Agents; Drug Resistance, Neoplasm; Female; Humans; Leukemia, T-Cell; Middle Aged; Tretinoin

We demonstrated significant growth inhibition by retinoic acid (RA) of HTLV-I (+) T-cell lines (ATL-2 and HUT102), but not HTLV-I (-) T-cell lines (MOLT-4 and Jurkat). We hypothesized that the mechanism of growth inhibition by RA depends on an imbalance in redox potential. To examine the effect of exogenous thiol compounds for the growth of HTLV-I (+) T-cell lines by RA, HTLV-I (+) T-cell lines were cultured with several thiol compounds (thioredoxin, L-cystine, and GSH), following addition of 13-cis RA or ATRA, respectively, in cultured with thiol free medium. Unexpectedly, thiol compounds alone did not restore growth inhibition of HTLV-I (+) T-cell lines. However, when those cells were preincubated with thiol compounds for 24 hours, no growth inhibition by 13-cis RA or ATRA was observed. These results suggest that thiol compounds are associated strongly with sensitivity to RA of HTLV-I (+) T cells, but not of HTLV-I (-) T cells and that thiol compounds serve an important role on HTLV-I (+) T cells.

Topics: Cell Division; Cell Survival; Culture Media; Deltaretrovirus Infections; Growth Inhibitors; Humans; Jurkat Cells; Leukemia, T-Cell; Sulfhydryl Compounds; T-Lymphocytes; Tretinoin; Tumor Cells, Cultured

Adult T-cell leukemia (ATL) is a peripheral T-cell neoplasm caused by human T-cell leukemia virus type I (HTLV-I). Despite the administration of combined intensive chemotherapy, the reported survival time of patients with acute and lymphoma types of ATL is less than 10 months. We therefore examine the effects of all-trans-retinoic acid (ATRA), 9-cis-RA and 13-cis-RA and tried to elucidate the mechanisms of inducing growth inhibition and apoptosis by these RAs using four ATL cell lines established in our laboratory. All the investigated RAs inhibited cell growth and the cells were arrested at the G1 phase. Apoptosis was induced in three out of four cell lines. Among the growth regulatory proteins examined, the level of p21Waf1/Cip1 protein was found to increase after RA treatment, thus resulting in pRb hypophosphorylation which also induced the arrest of the cells at the G1 phase. In addition, the p53 level decreased at the same time. Fas-FasL system and the downregulation of CD25 (IL-2R/alpha) expression did not seem to be involved. Based on these findings, the ability of RAs to induce a remission of ATL is thus strongly suggested.

Topics: Adult; Alitretinoin; Antigens, Surface; Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Cycle Proteins; Cell Division; Humans; Isotretinoin; Leukemia, T-Cell; Retinoids; Tretinoin; Tumor Cells, Cultured

The effects of retinoic acid (RA) on the cell growth and expression of interleukin-2 (IL-2) receptors (IL-2R alpha/p55, Tac, CD25) by the human T lymphotropic virus type I (HTLV-I)-positive T cell lines, HUT102 and ATL-2 were investigated. Incubation of these cells for 48 h with either 13-cis retinoid acid (13-cis RA) or all-trans retinoic acid (ATRA) resulted in marked inhibition of cell growth, determined by 3H-thymidine incorporation, and in down-regulation of CD25 expression, determined by flow cytometry. Four HUT102 cell clones were established by limiting dilution, and 13-cis RA was shown to inhibit cell growth and CD25 expression in three of these clones (HUT102-M5, -M6 and -M7), but not in the fourth (-M8). RA did not induce growth inhibition or down-regulation of CD25 in the HTLV-I-negative T cell lines (Jurkat and MOLT-4) and in normal lymphocytes that had been stimulated with phytohemagglutinin or phorbol 12-myristate 13-acetate. We have shown that RA markedly inhibited both the cell growth and the expression of CD25 in some HTLV-I-positive T cell clones, but not in normal lymphocytes. These results suggest that RA may be suitable for the treatment of patients with adult T cell leukemia (ATL).

Topics: Antigens, Neoplasm; Cell Division; Down-Regulation; Human T-lymphotropic virus 1; Humans; Leukemia, T-Cell; Leukocytes, Mononuclear; Lymphocyte Activation; Phytohemagglutinins; Receptors, Interleukin-2; Stimulation, Chemical; T-Lymphocytes; Thymidine; Tretinoin; Tritium; Tumor Cells, Cultured

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

The ability of retinoids to regulate interleukin-2 receptor (IL-2R) levels on human T-cells may play a fundamental role in the immunomodulating effects of these compounds. As a cell line model for studying this phenomenon, we tested the effects of retinoic acid (RA) on the expression of IL-2Ralpha and IL-2Rbeta in Hut78 cells, a mature T-cell line derived from a Sezary T-cell leukemia. Our results demonstrated 4- to 20-fold increases in the surface expression and mRNA levels of both of these receptor components at RA concentrations starting at 10(-10) M with maximal induction at 1 microM RA. RA-induced upregulation of IL-2Rbeta was found to be transcriptionally mediated in a protein-synthesis-independent fashion; however, activation of the IL-2Rbeta promoter could not be demonstrated in transient transfection experiments utilizing reporter gene constructs containing all currently known regulatory elements of the IL-2Rbeta promoter. Enhancement of IL-2Ralpha/beta by RA was accompanied by upregulation of the expression of CD38, CD69, CD45RO, and HLA-DR, surface molecules known to be associated with T-cell activation. Parallel effects were induced by RA on T-blasts generated from primary human lymphocytes suggesting the physiologic relevance of the Hut78 cell line model. Taken together, our findings demonstrate the ability of RA to upregulate IL-2R expression and enhance the activation state of Hut78 cells. The dramatic enhancing ability of RA on IL-2Rbeta expression does not appear to be mediated through interaction with currently defined regions of the IL-2Rbeta promoter.

Topics: Cell Nucleus; Humans; Immunophenotyping; Leukemia, T-Cell; Lymphocyte Activation; Nucleic Acid Hybridization; Promoter Regions, Genetic; Receptors, Interleukin-2; RNA, Messenger; T-Lymphocyte Subsets; T-Lymphocytes, Helper-Inducer; Tretinoin; Tumor Cells, Cultured

We observed the effects of the retinoic acid (13-cis retinoic acid; 13-cis RA, and all-trans retinoic acid; ATRA) for the cell growth and the expression of CD 25 on peripheral blood mononuclear cells (PBMC) from 17 patients with adult T cell leukemia (ATL). Fourteen had acute type, 1 had chronic type, and 2 had smoldering type of ATL. We divided those patient into 3 groups (hyper-sensitive, sensitive and resistant group) by determined with reduction rate of [3H]-thymidine incorporation obtained before and after treatment with 13 -cis RA or ATRA respectively. Growth inhibition was not observed in normal PBMC by 13 -cis RA or ATRA. However, no down-regulation of CD 25 expression was observed on PBMC in all patients and normal individuals after treatment with 13-cis RA or ATRA. In the aspect of growth inhibition on PBMC in ATL patients, we tried to clarify the mechanism of the phenomenon. In agarose gel electrophoresis, extracted genomic DNA from retinoic acid treated PBMC in hyper-sensitive and sensitive ATL patients showed multimer DNA fragmentation pattern. On the other hand, genomic DNA from PBMC after treatment with retinoic acid in resistant ATL patients and normal individuals showed high molecular DNA pattern without fragmentation. Taken together, it is suggested that retinoic acid could induce growth inhibition of PBMC in some ATL patients resulting in DNA fragmentation, apoptosis. We deeply consider that retinoic acid may be an useful agent for ATL patients in clinical aspect.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Cell Division; DNA, Neoplasm; Female; Humans; Leukemia, T-Cell; Male; Middle Aged; Monocytes; Receptors, Interleukin-2; Tretinoin

Topics: Adult; Antineoplastic Agents; Female; Humans; Leukemia, Promyelocytic, Acute; Leukemia, T-Cell; Remission Induction; Tretinoin

On the basis of early study on effects of retinoic acid (RA) on the differentiation of mouse lymphocytic leukemia-lymphoma cell strain (SACIIB 2), further research has been performed by studying the effects of retinoic acid on the human T lymphocytic leukemia cell line CCRF-CEM(CEM). The results showed that the growth of CEM cells was inhibited by RA at a concentration of 10 mumol/L. The activity of alpha-naphthyl acetate esterase (ANAE) and the percentage of CD3 positive cells rose after 10 days' RA treatment but the E rosette forming cells didn't increase. The activity of purine nucleoside phosphorylase (PNP) of the treated CEM cells increased significantly without change in activity of adenosine deaminase (ADA). The expression of terminal deoxynucleotidyl transferase (TdT) was also reduced to some degree. The analysis of lactic acid dehydrogenase (LDH) isoenzyme showed that the activity of LDH3 increased after RA treatment but without LDH1 and LDH2 expression. The results indicate that RA can induce CEM cells to differentiate.

Topics: CD3 Complex; Cell Differentiation; Humans; Isoenzymes; L-Lactate Dehydrogenase; Leukemia, T-Cell; Naphthol AS D Esterase; Purine-Nucleoside Phosphorylase; Tretinoin; Tumor Cells, Cultured