ABSTRACT
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.
Subject(s)
Antineoplastic Agents/pharmacology , Leukemia, T-Cell/drug therapy , Leukemia, T-Cell/metabolism , Signal Transduction/drug effects , Tretinoin/pharmacology , Adult , Cell Division/drug effects , Deltaretrovirus Infections/drug therapy , Deltaretrovirus Infections/metabolism , Deltaretrovirus Infections/physiopathology , Gene Expression Regulation, Leukemic/drug effects , Gene Expression Regulation, Viral/drug effects , Gene Products, gag/genetics , Gene Products, pol/genetics , Genes, pX/genetics , Human T-lymphotropic virus 1/genetics , Human T-lymphotropic virus 1/growth & development , Humans , In Vitro Techniques , Jurkat Cells , Leukemia, T-Cell/physiopathology , NF-kappa B/metabolism , Proviruses/genetics , Receptors, Interleukin-2/metabolism , Solubility , Transcriptional Activation/drug effects , Viral LoadSubject(s)
Human T-lymphotropic virus 1/isolation & purification , Oxidative Stress/drug effects , Sulfhydryl Compounds/pharmacology , T-Lymphocytes/metabolism , T-Lymphocytes/virology , Cell Line , Humans , Leukemia, T-Cell/drug therapy , Leukemia, T-Cell/metabolism , Leukemia, T-Cell/virology , Sulfhydryl Compounds/therapeutic useABSTRACT
A myeloid cell line (YM711) was established by transfecting exogenous PML/RARalpha cDNA into peripheral blood stem cells. The cells were positive for CD33, CD34, CD38, CD13, CD14, and CD11b. Cytochemical examination revealed YM711 cells to be positive for peroxidase, alpha-naphtyl butyrate esterase, and acid phosphatase as well. Karyotypic analysis showed them to be nearly tetraploid (92 XXYY). Reverse-transcription polymerase chain reaction showed that, although PML/RARalpha mRNA was detected in YM711, these cells could not be differentiated by all-trans retinoic acid (ATRA). We therefore designated the YM711 cell line as being ATRA resistant. Because YM711 expressed multi drug resistance 1 (MDR-1) mRNA and p-glycoprotein cell surface protein, we assessed whether verapamil and ATRA would induce the differentiation of YM711 cells; they did not. An increased expression of cellular retinoic acid-binding protein (CRABP)-II was also detected on YM711 cells compared with that of HL-60. These results suggest that high level of expression of CRABP-II may contribute to be the mechanism of ATRA resistance. This cell line may be useful in evaluating the mechanism of resistance to retinoid.
Subject(s)
Cell Line, Transformed/cytology , Myeloid Progenitor Cells/cytology , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , DNA, Complementary , Drug Resistance, Neoplasm , Flow Cytometry , Genes, MDR/genetics , Humans , Immunophenotyping , Neoplasm Proteins/genetics , Oncogene Proteins, Fusion/genetics , RNA, Messenger/metabolism , Receptors, Retinoic Acid/genetics , Reverse Transcriptase Polymerase Chain Reaction , Transfection , Tretinoin , Tumor Cells, CulturedABSTRACT
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).