cyclin-d1 and Leukemia-Lymphoma--Adult-T-Cell

Adult T-cell leukemia (ATL) is a fatal malignancy of T lymphocytes caused by infection with human T-cell leukemia virus type I (HTLV-I) and remains incurable. Curcumin (diferuloylmethane), the major pigment of the spice turmeric, can be potentially effective by promoting cell apoptosis. Here we examined whether curcumin is effective in the treatment of ATL. Curcumin prevented cell growth of HTLV-I-infected T-cell lines and primary ATL cells but not of normal peripheral blood mononuclear cells. Curcumin induced cell cycle arrest by reducing the expression of cyclin D1, Cdk1 and Cdc25C and apoptosis by reducing the expression of XIAP and survivin. Most of these genes are known to be regulated by NF-kappaB, which plays a critical role in oncogenesis by HTLV-I. Curcumin suppressed constitutive active NF-kappaB of HTLV-I-infected T-cell lines and primary ATL cells by inhibiting phosphorylation of IkappaBalpha. Curcumin also inhibited Tax-induced NF-kappaB transcriptional activity. However, curcumin-induced suppression of cell growth did not correlate with Tax expression level. Curcumin inhibited the growth of HTLV-I-infected T-cell tumors implanted subcutaneously in SCID mice. Our results indicate that curcumin has tumor-suppressive activity against ATL.

Topics: Adult; Animals; Antineoplastic Agents; Apoptosis; CDC2 Protein Kinase; cdc25 Phosphatases; Cell Cycle; Cell Cycle Proteins; Cell Proliferation; Curcumin; Cyclin D1; Female; Gene Products, tax; Human T-lymphotropic virus 1; Humans; Inhibitor of Apoptosis Proteins; Leukemia-Lymphoma, Adult T-Cell; Leukemia, T-Cell; Mice; Mice, Inbred ICR; Mice, SCID; Microtubule-Associated Proteins; Neoplasm Proteins; NF-kappa B; Survivin; T-Lymphocytes; Tumor Cells, Cultured; X-Linked Inhibitor of Apoptosis Protein

Adult T-cell leukemia (ATL) is caused by human T-cell leukemia virus type I (HTLV-I) and remains incurable. NIK-333, a novel synthetic retinoid, prevents the recurrence of human hepatoma after surgical resection of primary tumors. We explored the effects of NIK-333 on HTLV-I-infected T-cell lines and ATL cells. NIK-333 inhibited cell proliferation, induced G1 arrest, and resulted in massive apoptosis in all tested HTLV-I-infected T-cell lines and ATL cells, whereas little effect was observed on normal peripheral blood mononuclear cells. NIK-333 treatment decreases the levels of cyclin D1, cyclin D2, cIAP2, and XIAP proteins. Further analysis showed that NIK-333 inactivated nuclear factor-kappaB in HTLV-I-infected T-cell lines. In animal studies, treatment with NIK-333 (100 mg/kg given orally every other day) produced partial inhibition of growth of tumors of a HTLV-I-infected T-cell line transplanted s.c. in severe combined immunodeficient mice. Our results indicate that NIK-333 is a potentially useful therapeutic agent for patients with ATL.

Topics: Animals; Apoptosis; Cell Line, Transformed; Cell Line, Tumor; Cyclin D1; Cyclin D2; Cyclins; Down-Regulation; Female; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Inhibitor of Apoptosis Proteins; Leukemia-Lymphoma, Adult T-Cell; Leukemia, T-Cell; Mice; Mice, Inbred Strains; NF-kappa B; Retinoids; Signal Transduction; T-Lymphocytes; X-Linked Inhibitor of Apoptosis Protein

Histone deacetylase inhibitors (HDACIs) are a new class of chemotherapeutic drugs able to induce tumor cell apoptosis and/or cell cycle arrest; however, the molecular mechanisms underpinning their anticancer effects are poorly understood. Herein, we assessed the apoptotic pathways activated by three HDACIs, suberoylanilide hydroxamic acid, oxamflatin, and depsipeptide. We determined that all three drugs induced the accumulation of cells with a 4n DNA content and apoptosis mediated by the intrinsic apoptotic pathway. HDACI-induced mitochondrial membrane damage and apoptosis were inhibited by overexpression of Bcl-2, but not by the polycaspase inhibitor N-tert-butoxy-carbonyl-Val-Ala-Asp-fluoromethylketone (zVAD-fmk). Moreover, induction of a G(1)-S checkpoint through overexpression of p16(INK4A) or suppression of de novo protein synthesis also inhibited HDACI-induced cell death. Proteolytic cleavage of caspase-2, which is poorly inhibited by zVAD-fmk, was concomitant with HDACI-induced death; however, full processing of caspase-2 to the p19 active form was blocked by Bcl-2. Whereas all three drugs induce the activation of the proapoptotic Bcl-2 protein Bid upstream of mitochondrial membrane disruption, Bid cleavage in response to depsipeptide was significantly attenuated by zVAD-fmk. Suberoylanilide hydroxamic acid and oxamflatin could kill both P-glycoprotein (P-gp)(+) MDR cells and their P-gp(-) counterparts, whereas depsipeptide was shown to be a substrate for P-gp and was less effective in killing P-gp(+) cells. These data provide insight into the functional profile of three HDACIs and are important for the development of more rational approaches to chemotherapy, where information regarding the genetic profile of the tumor is matched with the functional profile of a given chemotherapeutic drug to promote favorable clinical responses.

Topics: Amino Acid Chloromethyl Ketones; Apoptosis; ATP Binding Cassette Transporter, Subfamily B, Member 1; Caspase Inhibitors; Cell Cycle; Cyclin D1; Cytochrome c Group; Depsipeptides; Enzyme Inhibitors; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Intracellular Membranes; Leukemia-Lymphoma, Adult T-Cell; Mitochondria; Peptides, Cyclic; Tumor Cells, Cultured; Vorinostat

Most lymphoid malignancies are initiated by specific chromosomal translocations between immunoglobulin (Ig)/T cell receptor (TCR) gene segments and cellular proto-oncogenes. In many cases, illegitimate V(D)J recombination has been proposed to be involved in the translocation process, but this has never been functionally established. Using extra-chromosomal recombination assays, we determined the ability of several proto-oncogenes to target V(D)J recombination, and assessed the impact of their recombinogenic potential on translocation rates in vivo. Our data support the involvement of 2 distinct mechanisms: translocations involving LMO2, TAL2, and TAL1 in T cell acute lymphoblastic leukemia (T-ALL), are compatible with illegitimate V(D)J recombination between a TCR locus and a proto-oncogene locus bearing a fortuitous but functional recombination site (type 1); in contrast, translocations involving BCL1 and BCL2 in B cell non-Hodgkin's lymphomas (B-NHL), are compatible with a process in which only the IgH locus breaks are mediated by V(D)J recombination (type 2). Most importantly, we show that the t(11;14)(p13;q32) translocation involving LMO2 is present at strikingly high frequency in normal human thymus, and that the recombinogenic potential conferred by the LMO2 cryptic site is directly predictive of the in vivo level of translocation at that locus. These findings provide new insights into the regulation forces acting upon genomic instability in B and T cell tumorigenesis.

Topics: Adaptor Proteins, Signal Transducing; Animals; Basic Helix-Loop-Helix Transcription Factors; Child; Cyclin D1; DNA-Binding Proteins; Humans; Leukemia-Lymphoma, Adult T-Cell; Leukemia, Lymphoid; LIM Domain Proteins; Lymphoma; Metalloproteins; Mice; Models, Genetic; Neoplasm Proteins; Proto-Oncogene Mas; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Recombination, Genetic; T-Cell Acute Lymphocytic Leukemia Protein 1; Thymus Gland; Transcription Factors; Translocation, Genetic

Both p16 and p15, encoded by genes located on chromosome 9p21, are inhibitors of cyclin-dependent kinases 4/6 (CDK4/6) and upstream regulators of RB function, and set up the RB/p16 tumor suppressive pathway, which is abrogated frequently in human neoplasms, either through inactivation of the RB or p16 tumor-suppressor protein, or alteration of the cyclin D1 or CDK4 oncoproteins. In hematological malignancies, deletion of p16/p15 locus has been shown to be highly specific to lymphoid malignancies, and more particularly to T-cell acute lymphoblastic leukemia (T-ALL). However, in the other subsets of ALL, deletions of p16 and p15 are relatively rare events. To investigate whether these genes are inactivated by methylation of the 5' CpG islands, we examined 35 leukemia cell lines and 29 childhood acute myeloid leukemia (AML) patients by Southern blot, polymerase chain reaction (PCR) and Western blot analyses. We found methylation of p16 in 12 (50%) of 24 ALL cell lines, 5 (50%) of 10 AML cell lines without homozygous deletion of p16, and 11 (38%) of 29 AML patients. Those leukemia cell lines subjected to p16 methylation were found to have lost p16 protein expression. The p15 gene was methylated in 10 (34%) of 29 ALL cell lines, 6 (60%) of 10 AML cell lines without homozygous deletion of p15, and 15 (52%) of 29 AML patients. These results revealed the frequent methylation of p16 and p15 genes in B-ALL and AML despite a low frequency of p16 and p15 deletions and mutations in these leukemias. In the study for expression of RB protein, we found no expression of RB in 4 of 16 leukemia cell lines. Inactivation of the p16 gene was found in all the cell lines with expression of RB. Neither amplification nor rearrangement of cyclin D1 gene was found in any cell lines. These results suggest that inactivation of p16 and p15 genes is one of the most common genetic events in acute leukemia, and plays an important role for the RB/p16 pathway in the pathogenesis of acute leukemia.

Topics: Acute Disease; Burkitt Lymphoma; Carrier Proteins; Cell Cycle Proteins; CpG Islands; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p15; Cyclin-Dependent Kinase Inhibitor p16; DNA Methylation; DNA, Neoplasm; Gene Expression Regulation, Leukemic; Genes, p16; Genes, Retinoblastoma; Humans; Leukemia-Lymphoma, Adult T-Cell; Leukemia, Myeloid; Loss of Heterozygosity; Molecular Probe Techniques; Neoplasm Proteins; Polymerase Chain Reaction; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Retinoblastoma Protein; Sequence Deletion; Tumor Cells, Cultured; Tumor Suppressor Proteins

Retinoids, the analogues of vitamin A, have a broad range of effects on different cell types. One biologically active form of vitamin A is all-trans-retinoic acid (ATRA), which binds to retinoic acid receptors, as does its intracellular metabolite, 9-cis-RA. Earlier studies have documented G1 cell cycle arrest and the induction of apoptosis in human adult T-cell leukemia cells after ATRA treatment. Previous work exploring the growth-inhibitory activity of ATRA in human malignancies has implicated several mechanisms that can arrest cells in the G1 phase of the cell cycle, including activation of p21Waf1 and inhibition of cyclin D1 expression. Therefore, we decided to examine the effects of ATRA exposure on G1 cell cycle components in human adult T-cell leukemia cells. Our data demonstrate a correlation between cyclin/cyclin-dependent kinase activity and subunit complex formation with duration of drug exposure. We also observed an increase in p53 protein levels that were not associated with an increase in p21Waf1 levels. Furthermore, we observed a differential effect on cell cycle progression that was temporally related to length of ATRA exposure. These observations, consistent with a bimodal effect of ATRA on cell cycle progression, may have important implications for the clinical application of ATRA.

Topics: Antineoplastic Agents; Cell Cycle; Cell Line, Transformed; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase 6; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinases; Cyclins; G1 Phase; Human T-lymphotropic virus 1; Humans; Leukemia-Lymphoma, Adult T-Cell; Precipitin Tests; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; T-Lymphocytes; Tretinoin; Tumor Cells, Cultured; Tumor Suppressor Protein p53

t(11;14)(q13;q32) observed in B-cell malignancies is associated with cyclin D1 (bcl-1, PRAD1, CCND1) overexpression. We devised a simple competitive reverse transcription-polymerase chain reaction (RT-PCR) assay for rapid detection of cyclin D1 overexpression. Sharing a single upstream primer derived from a homologous sequence in cyclins D1, D2 and D3, each PCR product serves as a competitor and cyclin D1 overexpression is determined by comparing the intensities of the three amplified products. We analyzed cyclin D1 in clinical specimens from 104 patients with lymphoid malignancies. Cyclin D1 overexpression was evident in 13 of 104 (7/72 non-Hodgkin's lymphomas, 0/6 adult T-cell lymphoma/leukemias, 0/4 Hodgkin's diseases, 0/11 acute lymphoblastic leukemias, 3/4 multiple myelomas, 1/2 Waldenström's macroglobulinemias, 1/2 prolymphocytic leukemias and 1/3 chronic lymphocytic leukemias). Among 72 patients for whom cytogenetic studies had been done, all 7 patients with t(11;14) were positive. The relative expression levels of D-type cyclins altered dramatically in the presence of t(11;14). Thus, this RT-PCR assay can identify tumors with cyclin D1 overexpression. Cyclin D1 overexpression was frequent in extranodal specimens (11 out of 32 vs. 2 of 72 lymph nodes) and was restricted to specific types of lymphoid malignancies, as observed using other methods. This reliable assay should be suitable to provide clinical guidance for the diagnosis and management of lymphoid malignancies, especially in the case of extranodal involvement.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Bone Marrow; Cyclin D1; Female; Hodgkin Disease; Humans; Leukemia-Lymphoma, Adult T-Cell; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, Non-Hodgkin; Lymphoproliferative Disorders; Male; Middle Aged; Multiple Myeloma; Polymerase Chain Reaction; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Transcription, Genetic; Waldenstrom Macroglobulinemia