cyclin-d1 and Burkitt-Lymphoma

Topics: Base Sequence; Burkitt Lymphoma; Cell Transformation, Neoplastic; Chromosomes, Human, Pair 14; Chromosomes, Human, Pair 22; Chromosomes, Human, Pair 8; Cloning, Molecular; Cyclin D1; Gene Rearrangement; Genes, myc; Humans; Molecular Sequence Data; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Translocation, Genetic

Burkitt lymphoma (BL) has a high mortality rate and its treatment is currently limited to chemotherapy combined with immunotherapy. The long non‑coding RNA antisense non‑coding RNA in the INK4 locus (ANRIL) has been identified as an oncogene that can regulate cell proliferation and apoptosis in multiple types of cancer. However, the function of ANRIL in BL remains unknown. The present study aimed to determine the effect of ANRIL on cell proliferation and apoptosis in BL. Reverse transcription‑quantitative PCR was used to analyze the expression levels of ANRIL in BL cells. The effect of ANRIL knockdown on BL cells was determined using Cell Counting Kit‑8, flow cytometric, western blotting, immunofluorescence staining and Hoechst staining assays. The results revealed that ANRIL silencing inhibited the proliferation and promoted the apoptosis of BL cells. In addition, the expression levels of cyclin D1, E2F transcription factor 1 and Bcl‑2 were downregulated, while the expression levels of cyclin‑dependent kinase inhibitor 1A, Bcl‑2‑associated X protein, cleaved‑caspase‑9/pro‑caspase‑9 and cleaved‑caspase‑3/pro‑caspase‑3 were upregulated. Furthermore, the knockdown of ANRIL activated the TGF‑β1 signaling pathway, as evidenced by the upregulated expression levels of TGF‑β1, phosphorylated (p)‑SMAD2/3/SMAD2/3, p‑SMAD1/SMAD1 and sphingosine‑1‑phosphate receptor 2. Moreover, the protective effect of ANRIL silencing in BL could be inhibited by the TGF‑β receptor type I/II dual inhibitor, LY2109761. In conclusion, the findings of the present study suggested that the knockdown of ANRIL may inhibit cell proliferation and promote cell apoptosis in BL by regulating the TGF‑β1 signaling pathway, which may provide a novel target for the treatment of BL.

Topics: Apoptosis; bcl-2-Associated X Protein; Burkitt Lymphoma; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p21; E2F1 Transcription Factor; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; RNA, Long Noncoding; Signal Transduction; Transforming Growth Factor beta1

The MYC transcription factor plays a crucial role in the regulation of cell cycle progression, apoptosis, angiogenesis, and cellular transformation. Due to its oncogenic activities and overexpression in a majority of human cancers, it is an interesting target for novel drug therapies. MYC binding to the E-box (5'-CACGTGT-3') sequence at gene promoters contributes to more than 4000 MYC-dependent transcripts. Owing to its importance in MYC regulation, we designed a novel sequence-specific DNA-binding pyrrole-imidazole (PI) polyamide, Myc-5, that recognizes the E-box consensus sequence. Bioinformatics analysis revealed that the Myc-5 binding sequence appeared in 5'- MYC binding E-box sequences at the eIF4G1, CCND1, and CDK4 gene promoters. Furthermore, ChIP coupled with detection by quantitative PCR indicated that Myc-5 has the ability to inhibit MYC binding at the target gene promoters and thus cause downregulation at the mRNA level and protein expression of its target genes in human Burkitt's lymphoma model cell line, P493.6, carrying an inducible MYC repression system and the K562 (human chronic myelogenous leukemia) cell line. Single i.v. injection of Myc-5 at 7.5 mg/kg dose caused significant tumor growth inhibition in a MYC-dependent tumor xenograft model without evidence of toxicity. We report here a compelling rationale for the identification of a PI polyamide that inhibits a part of E-box-mediated MYC downstream gene expression and is a model for showing that phenotype-associated MYC downstream gene targets consequently inhibit MYC-dependent tumor growth.

Topics: Animals; Apoptosis; Binding Sites; Burkitt Lymphoma; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase 4; DNA-Binding Proteins; E-Box Elements; Eukaryotic Initiation Factor-4G; Humans; Imidazoles; Mice; Mice, SCID; Nylons; Promoter Regions, Genetic; Protein Binding; Proto-Oncogene Proteins c-myc; Pyrroles; Xenograft Model Antitumor Assays

In this study, we define the genetic landscape of mantle cell lymphoma (MCL) through exome sequencing of 56 cases of MCL. We identified recurrent mutations in ATM, CCND1, MLL2, and TP53. We further identified a number of novel genes recurrently mutated in patients with MCL including RB1, WHSC1, POT1, and SMARCA4. We noted that MCLs have a distinct mutational profile compared with lymphomas from other B-cell stages. The ENCODE project has defined the chromatin structure of many cell types. However, a similar characterization of primary human mature B cells has been lacking. We defined, for the first time, the chromatin structure of primary human naïve, germinal center, and memory B cells through chromatin immunoprecipitation and sequencing for H3K4me1, H3K4me3, H3Ac, H3K36me3, H3K27me3, and PolII. We found that somatic mutations that occur more frequently in either MCLs or Burkitt lymphomas were associated with open chromatin in their respective B cells of origin, naïve B cells, and germinal center B cells. Our work thus elucidates the landscape of gene-coding mutations in MCL and the critical interplay between epigenetic alterations associated with B-cell differentiation and the acquisition of somatic mutations in cancer.

Topics: Ataxia Telangiectasia Mutated Proteins; B-Lymphocytes; Burkitt Lymphoma; Chromatin; Cyclin D1; DNA Helicases; DNA-Binding Proteins; Epigenesis, Genetic; Exome; Gene Regulatory Networks; Genomics; Germinal Center; Histone-Lysine N-Methyltransferase; Histones; Humans; Lymphoma, Mantle-Cell; Methylation; Mutation; Neoplasm Proteins; Nuclear Proteins; Repressor Proteins; Retinoblastoma Protein; Sequence Analysis, DNA; Shelterin Complex; Telomere-Binding Proteins; Transcription Factors; Tumor Suppressor Protein p53

Anti-lymphoma therapy continues to present a major challenge. Even though cytotoxic therapy, immunotherapy and molecularly targeted therapy have been used in the clinic to treat the disease, effective anti-lymphoma drugs are still needed. In this study, we explored novel anti-lymphoma agents and found that scutellarin, an active component of a traditional Chinese medicinal herb Erigeron breviscapus, executed an anti-lymphoma effect. Scutellarin diminished the proliferation of B-lymphoma Namalwa cells in vitro and inhibited lymphoma growth in Namalwa cell-xenotransplanted mice without obvious toxicity. A mechanism study showed that scutellarin at doses of less than 10 μM induced cell cycle arrest at G0/G1 transition without the induction of cell apoptosis, which was accompanied by down-regulation of cyclin D1 and CDK4 expression. In contrast, scutellarin at concentrations of 15 μM or above promoted Namalwa cell apoptosis, which was partially associated with the activation of caspases. These results suggest that scutellarin is a new potential anti-lymphoma candidate.

Topics: Animals; Apigenin; Apoptosis; Blotting, Western; Burkitt Lymphoma; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Dose-Response Relationship, Drug; Erigeron; Female; Gene Expression; Glucuronates; HeLa Cells; HL-60 Cells; Humans; Jurkat Cells; Mice; Mice, Inbred BALB C; Mice, Nude; Molecular Structure; Phytotherapy; Reverse Transcriptase Polymerase Chain Reaction; U937 Cells; Xenograft Model Antitumor Assays

Fucoxanthin (FX) is a natural carotenoid with reported antitumorigenic activity. This study explored the effects of FX and its deacetylated product, fucoxanthinol (FXOH), on B-cell malignancies, including Burkitt's lymphoma, Hodgkin's lymphoma and Epstein-Barr virus-immortalized B cells. Both FX and FXOH reduced the viability of these malignant B cells in a dose-dependent manner accompanied by the induction of cell cycle arrest during G1 phase and caspase-dependent apoptosis. FXOH was approximately twice more potent than FX in these activities. In contrast, normal peripheral blood mononuclear cells were resistant to FX and FXOH. Strong and constitutive activation of nuclear factor-κB (NF-κB) is a common characteristic of many B-cell malignancies, and FXOH suppressed constitutive NF-κB activity. NF-κB inhibition was accompanied by downregulation of NF-κB-dependent anti-apoptotic and cell cycle regulator gene products, including Bcl-2, cIAP-2, XIAP, cyclin D1 and cyclin D2. The results indicated that FX and FXOH are potentially useful therapeutic agents in B-cell malignancies characterized by aberrant regulation of NF-κB.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; B-Lymphocytes; beta Carotene; Burkitt Lymphoma; Caspases; Cell Line, Transformed; Cyclin D1; Cyclin D2; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Herpesvirus 4, Human; Hodgkin Disease; Humans; NF-kappa B; X-Linked Inhibitor of Apoptosis Protein; Xanthophylls

Previous studies have implicated activation-induced cytidine deaminase (AID) in B-cell translocations but have failed to identify any association between their chromosomal breakpoints and known AID target sequences. Analysis of 56 unclustered IgH-CCND1 translocations in mantle cell lymphoma across the ~ 344-kb bcl-1 breakpoint locus demonstrates that half of the CCND1 breaks are near CpG dinucleotides. Most of these CpG breaks are at CGC motifs, and half of the remaining breaks are near WGCW, both known AID targets. These findings provide the strongest evidence to date that AID initiates chromosomal breaks in translocations that occur in human bone marrow B-cell progenitors. We also identify WGCW breaks at the MYC locus in Burkitt lymphoma translocations and murine IgH-MYC translocations, both of which arise in mature germinal center B cells. Finally, we propose a developmental model to explain the transition from CpG breaks in early human B-cell progenitors to WGCW breaks in later stage B cells.

Topics: Animals; Burkitt Lymphoma; Chromosome Breakage; Chromosomes, Human, Pair 11; Chromosomes, Human, Pair 14; Chromosomes, Human, Pair 8; Comparative Genomic Hybridization; CpG Islands; Cyclin D1; Cytidine Deaminase; Genes, myc; Humans; Immunoglobulin Heavy Chains; Lymphoma, Mantle-Cell; Mice; Oncogene Proteins, Fusion; Translocation, Genetic

We surveyed lymphomas to determine the range of expression of the mantle cell lymphoma-associated SOX11 transcription factor and its relation to cyclin D1.. On hundred and seventy-two specimens were immunostained for the SOX11 N and C termini. Cyclin D1 was detected by immunohistochemistry and quantitative reverse transcriptase polymerase chain reaction; in situ hybridization for t(11;14) was applied when needed.. Nuclear SOX11 was strongly expressed in most B and T-lymphoblastic leukemia/lymphomas and half of childhood Burkitt's lymphomas, but only weakly expressed in some hairy cell leukemias. Chronic lymphocytic leukemia/lymphoma, marginal zone, follicular and diffuse large B-cell lymphomas were negative for SOX11, as were all cases of intermediate Burkitt's lymphomas/diffuse large B-cell lymphoma, myeloma, Hodgkin's lymphomas and mature T-cell and NK/T-cell lymphomas.. In addition to mantle cell lymphoma, SOX11 is strongly expressed only in lymphoblastic malignancies and Burkitt's lymphomas. Its expression is independent of cyclin D1 (except for weak expression in hairy cell leukemias) and unlikely to be due to translocations in lymphoid neoplasia.

Topics: Burkitt Lymphoma; Cyclin D1; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Lymphoma, Mantle-Cell; Polymerase Chain Reaction; Precursor Cell Lymphoblastic Leukemia-Lymphoma; SOXC Transcription Factors

To investigate the anticancer effects and molecular mechanism of deguelin on human Burkitt's lymphoma Daudi cells in vitro and compare the cytotoxicity of deguelin on Daudi cells and human peripheral blood monocular cells (HPBMC).. The effects of deguelin on the growth of Daudi cells were studied by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5 diphenyl-2H-tetrazolium (MTT) assay. Apoptosis was assessed through Hoechst 33258 staining and annexin V/PI double-labeled cytometry. The effect of deguelin on the cell cycle of Daudi cells was studied by propidium iodide method. The expressions of cyclin D1 and pRb were checked by Western blot.. The proliferation of Daudi cells was decreased in deguelin-treated group with a 24 h IC50 value of 51. 55 nmol/L. Deguelin induced Daudi cells apoptosis in a time- and dose-dependent manner. Daudi cells treated with deguelin showed an increase of G0/G1 phase and decrease of S phase. The Daudi cells treated with 0, 5, 10, 20, 40 nmol/L deguelin for 24 h, showed an increased Go/G, phase from 37.34% to 56.56% , whereas decreased S phase from 37.72% to 21.36%, respectively. PBMC was less sensitive to the cytotoxic effect of deguelin than Daudi cells. The expression of cyclin D1 and pRb protein were decreased in Daudi cells treated with deguelin.. Deguelin can inhibit the proliferation of Daudi cells by regulating the cell cycle that arrest cells at G0/G1 phase and inducing apoptosis. Moreover, deguelin demonstrats low toxicity in PBMC but selectively induces apoptosis of Daudi cells. The antitumor effects of deguelin may be related to down-regulation of the expression of cyclin D1 and pRb protein.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Burkitt Lymphoma; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Dose-Response Relationship, Drug; Down-Regulation; Flow Cytometry; Humans; Leukocytes, Mononuclear; Retinoblastoma Protein; Rotenone

To investigate anticancer effects and molecular mechanism of deguelin on human Burkittos lymphoma Daudi cells in vitro and compare the cytotoxicities of deguelin on Daudi cells and human peripheral blood monocular cells (PBMC).. The effects of deguelin on the growth of Daudi cells were studied by 3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) assay. Apoptosis were detected through Hoechst 33258 staining and Annexin V/PI double-labeled cytometry. The effect of deguelin on the cell cycle of Daudi cells were studied by a propidium iodide method. The expressions of cyclin D1 and pRb were checked by Western blot.. The proliferation of Daudi cells were decreased in deguelin-treated group with a 24-h IC50 value of 51.55 nmol/L. Deguelin induced Daudi cells apoptosis was in a time- and dose-dependent manner. G0/G1 phase increased and S phase decreased in Daudi cells treated with deguelin. With deguelin 0, 5, 10, 20, and 40 nmol/L treatment for 24 h, G0/G1 phase increased from 37.34% to 56.56%, whereas S phase decreased from 37.72% to 21.36%. PBMC was less sensitive to the cytotoxic effect of deguelin than Daudi cells. The expression of cyclin D1 and pRb protein were decreased sharply in Daudi cells treated with deguelin.. Deguelin is able to inhibit the proliferation of Daudi cells by regulating the cell cycle that arrested cells at G0/G1 phase and inducing the cell apoptosis. Moreover, deguelin selectively induced apoptosis of Daudi cells with low toxicity in PBMC. The antitumor effects of deguelin were related to down-regulating the expression of cyclin D1 and pRb protein.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Burkitt Lymphoma; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Dose-Response Relationship, Drug; Humans; Leukocytes, Mononuclear; Retinoblastoma Protein; Rotenone

The associated poor prognosis and potentially aggressive behavior of mantle cell lymphoma and its blastoid variants make differentiation from other non-Hodgkin B-cell lymphomas especially important. We present a case of mantle cell lymphoma with a marked leukemic component, which demonstrated both a typical nodular mantle cell pattern and Burkitt lymphoma within a single lymph node removed at the time of splenectomy. The presence of CD5, CD10, and Bcl-1 co-expression by immunohistochemistry and detectable t(11;14) and cMYC gene rearrangement by FISH analyses in the Burkitt region support a transformation of mantle cell lymphoma over a concomitant malignancy. A limited number of mantle cell lymphomas demonstrating dual t(11;14) and chromosome 8q24 cMYC gene rearrangements have been previously reported in the literature. They demonstrate an extremely aggressive course with a very poor prognosis. Although the accelerated terminal phase of this patient's clinical course mirrors these previous published cases; none have described the combined morphologic and immunophenotypic features of Burkitt lymphoma reported here. This case provides further support for the aggressive nature of these lymphomas and demonstrates the utility of flow cytometry, immunohistochemistry, and cytogenetic techniques in avoiding potential errors in their diagnosis, prognosis, and treatment.

Topics: Burkitt Lymphoma; Cell Transformation, Viral; Cyclin D1; Female; Gene Rearrangement; Genes, myc; Herpesvirus 4, Human; Humans; Leukemia; Lymph Nodes; Lymphoma, Mantle-Cell; Middle Aged; Splenectomy

We showed heterogeneous disease spectrum among 15 acute lymphoblastic leukemia (ALL) cases with mature B-cell phenotype diagnosed over the past 7 years at our institution. Besides those with typical L3 morphology and 8q24 (c-myc) translocation (n=6), there were cases showing L1 or L2 morphology without 8q24 translocation (n=6), unusually large L3 blasts in hyperdiploid clone (n=2) and blastoid variant of mantle cell lymphoma (n=1). The expression of CD5 and cyclin D1 may need to be routinely determined on ALL cases with mature B-cell phenotype and non-L3 morphology to facilitate timely diagnosis of blastoid MCL and institution of suitable management.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Bone Marrow Examination; Burkitt Lymphoma; CD5 Antigens; Child; Child, Preschool; Chromosomes, Human, Pair 14; Chromosomes, Human, Pair 8; Cyclin D1; Cytogenetic Analysis; Female; Humans; Immunophenotyping; Lymphoma, Mantle-Cell; Male; Middle Aged; Phenotype; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Retrospective Studies; Translocation, Genetic

Mantle cell lymphoma (MCL) is a moderately aggressive B-cell lymphoma that responds poorly to currently used therapeutic protocols. In order to identify tumour characteristics that improve the understanding of biology of MCL, analysis of oligonucleotide microarrays were used to define specific gene expression profiles. Biopsy samples of MCL cases were compared to reactive lymphoid tissue. Among genes differentially expressed in MCL were genes that are involved in the regulation of proliferation, cell signalling, adhesion and homing. Furthermore, some genes with previously unknown function, such as C11orf32, C2orf10, TBC1D9 and ABCA6 were found to be differentially expressed in MCL compared to reactive lymphoid tissue. Of special interest was the high expression of the cannabinoid receptor 1 (CB1) gene in all MCL cases analysed. These results were further confirmed at the cellular and protein level by immunocytochemical staining and immunoblotting of MCL cells. Furthermore, there was a reduced expression of a regulator of G protein signalling, RGS13 in all MCLs, with a complete absence in the majority of cases while present in control lymphoid tissue. These results were further confirmed by PCR. Sequencing of the RGS13 gene revealed changes suggesting polymorphisms, indicating that downregulation of the expression of RGS13 is not related to mutations, but may serve as a new specific marker for MCL. Moreover, comparison between individual cases of MCL, revealed that the CCND1 gene appears to be differently expressed in MCL cases with high vs low proliferative activity.

Topics: Adolescent; Adult; Aged; Burkitt Lymphoma; Case-Control Studies; Cell Division; Cell Transformation, Neoplastic; Child; Cyclin D1; DNA, Neoplasm; Down-Regulation; Female; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; In Situ Hybridization, Fluorescence; Leukemia, B-Cell; Lymphoma, Mantle-Cell; Male; Middle Aged; Neoplasm Proteins; Oligonucleotide Array Sequence Analysis; Receptors, Cannabinoid; Receptors, Drug; Reverse Transcriptase Polymerase Chain Reaction; RGS Proteins; RNA, Messenger; RNA, Neoplasm

Cyclin D1 overexpression is a valuable marker for the diagnosis of mantle cell lymphoma (MCL). We used a real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) method to quantify levels of cyclin D1, CD20, and cyclophilin A mRNA in manually microdissected, paraffin-embedded tissue sections using an ABI 7700 qRT-PCR system. The study group included 21 cases of MCL and 37 cases of other types of B-cell non-Hodgkin's lymphoma. Cyclin D1 mRNA copy number was normalized to CD20 and cyclophilin A mRNA and evaluated statistically by analysis of variance. The relative cyclin D1 levels were similar whether normalized to CD20 or cyclophilin A, indicating that CD20 levels are stable and can be used as a B-cell-specific normalizer. Statistically significant differences were found in the median levels of cyclin D1 mRNA (expressed as % CD20 mRNA) among cases of MCL (87.6), small lymphocytic lymphoma (9.9), follicular lymphoma (2.4), diffuse large B-cell lymphoma (5.9), marginal zone B-cell lymphoma (39.8), and Burkitt lymphoma (7.1) (P < 0.05). We conclude that qRT-PCR can be used to quantify cyclin D1 mRNA levels in archival tissue sections. Normalization of cyclin D1 to a B-cell-specific marker more accurately reflects overexpression by MCL than other methods that normalize using constitutively expressed mRNA species.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antigens, CD20; Archives; Biomarkers, Tumor; Burkitt Lymphoma; Cyclin D1; Cyclophilin A; DNA Primers; Female; Humans; Immunoenzyme Techniques; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, B-Cell; Lymphoma, Large B-Cell, Diffuse; Lymphoma, Mantle-Cell; Lymphoma, Non-Hodgkin; Male; Middle Aged; Paraffin Embedding; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; RNA, Neoplasm

BCL-1 rearrangement (BCL-1/IgH gene rearrangement) in acute lymphocytic leukemia and its clinical significance was investigated. In 38 patients with acute lymphocytic leukemia (ALL), the genomic DNA of mononuclear cells isolated from peripheral blood and bone marrow was amplified by using hemi-nested polymerase chain reaction (PCR) technique and the expression of cyclin D1 protein of mononuclear cells was detected by using immunohistochemical method. Ten patients with acute granulocytic leukemia, 2 with chronic granulocytic leukemia and 10 with normal bone marrow served as control group. The results showed that BCL-1 rearrangement was detectable in 3 of 38 ALL patients (7.9%) and cyclin D1 protein positive expression was detected in 4 ALL patients (10.5%). Three ALL patients with BCL-1 rearrangement were all B-cell leukemia (B-ALL) and accompanied by cyclin D1 protein expression. No BCL-1/IgH rearrangement or cyclin D1 protein expression was detected in 12 patients with granulocytic leukemia and 10 cases of normal bone marrow. Leukocyte counts in peripheral blood of B-ALL patients with BCL-1 rearrangement and (or) cyclin D1 protein expression were significantly increased and the patients had bad reaction to chemotherapy. It was concluded that: 1) BCL-1/IgH gene rearrangement were detected in acute B lymphocytic leukemia; 2) B-ALL patients with BCL-1 rearrangement and (or) cyclin D1 protein expression had poor prognosis.

Topics: Adolescent; Adult; Burkitt Lymphoma; Child; Cyclin D1; Female; Gene Rearrangement; Genes, bcl-1; Humans; Immunoglobulin Heavy Chains; Male; Middle Aged; Phenotype; Precursor Cell Lymphoblastic Leukemia-Lymphoma

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

Six patients had blood and bone marrow manifestations characterized by the presence of morphologically immature or blastic B-lineage lymphoid cells expressing CD5 antigen. The median patient age was 70 years, and the male-to-female ratio was 5:1. The presence or degree of lymphadenopathy and splenomegaly was variable among this group at staging evaluation, although two patients did not have these features. One patient had an antecedent diagnosis of classical nodal mantle cell lymphoma, without prior morphologic blood or bone marrow involvement. Other patients lacked a history of underlying lymphoproliferative disorders. The median white blood cell count was 120 x 10(9)/L. Most patients had thrombocytopenia, whereas only one patient had neutropenia at presentation. Leukemic peripheral blood cells in these six cases were small to medium in size with fine or granular nuclear chromatin and small or inconspicuous nucleoli. The pattern of marrow involvement was interstitial or diffuse, with cells showing immature nuclear features resembling acute leukemia or blastic lymphoma. All tumors demonstrated a consistent immunophenotype of B-cell lineage, surface immunoglobulin positivity, and CD5 antigen expression. The progenitor cell-associated markers CD34 and TdT were not expressed, and CD23 antigen was either negative (three of four cases) or only weakly present (one of four cases). The presence of a karyotypic t(11;14)(q13;q32) was documented in one tumor, whereas two other cases had BCL-1 gene rearrangements by either polymerase chain reaction or Southern blot analysis. Cyclin D1 mRNA overexpression was noted in three of four cases tested. This patient group was characterized by very poor overall survival (median, 3 months; range, 0.5 to 6 months). The aggregate clinical, pathologic, and genetic data in these unusual cases are consistent with de novo or predominant leukemic presentations of blastic mantle cell lymphoma. Accurate diagnosis in such cases is greatly facilitated by cytogenetic studies or the demonstration of BCL-1/cyclin D1 abnormalities.

Topics: Aged; Aged, 80 and over; Bone Marrow; Burkitt Lymphoma; CD5 Antigens; Cyclin D1; Cytogenetics; Diagnosis, Differential; DNA Primers; DNA, Neoplasm; Female; Gene Rearrangement; Genes, bcl-1; Humans; Immunoenzyme Techniques; Immunophenotyping; Lymphoma, Mantle-Cell; Male; Middle Aged; Receptors, Antigen, B-Cell; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

The cyclin-D1/PRAD1 oncogene, a key regulator of the G1-phase progression of the cell cycle, has been identified as the long-sought BCL-1 oncogene in B-cell malignancies with t(11;14)(q13;q32) translocation. A novel alternative spliced cyclin-D1 transcript, called transcript[b], has been identified. The level of the variant transcript[b] was lower than that of the originally reported cyclin-D1 transcript, called transcript[a], in several human non-lymphoid cancer cell lines but the endogenous cellular expression of transcript[b] products has not yet been determined. Northern-blot analysis and reverse-transcription-polymerase-chain-reaction (RT-PCR) analysis revealed that transcript[b] mRNA is well expressed in B-lymphoid cell lines with t(11;14)(q13;q32) translocation and at much lower or undetectable levels in other cells. Western-blot analysis using a human cyclin-D1-specific monoclonal antibody, which can recognize and distinguish the products of transcripts [a] and [b], strongly suggested that the transcript [b] protein is indeed expressed in these B-cell lines. The present study provides identification of the endogenous cellular expression of the cyclin-D1-transcript[b] protein and strongly suggests that this alternative form of cyclin D1 may play a significant role in the molecular pathogenesis of B-lymphoid malignancies with t(11;14)(q13;q32) translocation.

Topics: Alternative Splicing; Animals; Breast Neoplasms; Burkitt Lymphoma; Chromosome Mapping; Chromosomes, Human, Pair 11; Chromosomes, Human, Pair 14; Cyclin D1; Female; Humans; Jurkat Cells; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, B-Cell; Mice; Reverse Transcriptase Polymerase Chain Reaction; Transcription, Genetic; Translocation, Genetic; Tumor Cells, Cultured

In the present study, we report the cyclin-dependent kinase (Cdk)-inhibitory activity of a series of p21waf1/cip1 (p21) peptide fragments spanning the whole protein against the cyclin D1/Cdk4 and cyclin E/Cdk2 enzymes. The most potent p21 peptide tested in our initial peptide series, designated W10, spanned amino acids 139 to 164, a region of p21 that has been found independently to bind to proliferating cell nuclear antigen and also to inhibit Cdk activity. We go on to report the importance of putative beta-strand and 3(10)-helix motifs in the W10 peptide for cyclin-dependent kinase-inhibitory activity. We also describe the cellular activity of W10 and derivatives that were chemically linked to an antennapedia peptide, the latter segment acting as a cell membrane carrier. We found that the W10AP peptide exhibited growth inhibition that resulted from necrosis in human lymphoma CA46 cells. Furthermore, regions in the W10 peptide responsible for Cdk-inhibition were also important for the degree of this cellular activity. These studies provide insights that may eventually, through further design, yield agents for the therapy of cancer.

Topics: Amino Acid Sequence; Antennapedia Homeodomain Protein; Burkitt Lymphoma; Cell Membrane; Cyclin D1; Cyclin E; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Flow Cytometry; Homeodomain Proteins; Humans; Microscopy, Electron; Molecular Sequence Data; Necrosis; Neoplasm Proteins; Nuclear Proteins; Peptide Fragments; Proliferating Cell Nuclear Antigen; Structure-Activity Relationship; Transcription Factors; Tumor Cells, Cultured

To assess the biologic relevance of the morphologic distinctions between subtypes of small noncleaved cell lymphomas (SNCL), ie, the sporadic Burkitt's type (sBT) and the non-Burkitt's type (nBT), we have examined the molecular organization of several lymphomagenic oncogenes (c-myc, bcl-1, bcl-2) and the potential pathogenetic contribution of the Epstein-Barr virus (EBV). Twenty-nine cases of SNCL, not associated with immunodeficiency syndromes, were reviewed and classified as sBT (18 cases) or nBT (11 cases) without knowledge of the clinical or molecular data. Southern blot analysis of 18 sBTs found 17 to contain c-myc rearrangements. Fifteen of these comigrated with an Ig heavy-chain gene segment, indicating t(8;14) translocation. Chromosome 8 breakpoints were clustered in the first exon and the first intron of the c-myc gene. Chromosome 14 breakpoints mapped to the JH locus in three tumors, the S mu locus in nine tumors, and the S alpha locus in the remaining three tumors. Cases involving the S alpha locus appeared to have a more rapid clinical course. All sBTs possessed germline bcl-2 and bcl-1 gene fragments. In contrast, Southern blot analysis of 11 nBTs found none with c-myc rearrangements. Rather, three of 10 evaluable nBTs had bcl-2 rearrangements. The remaining seven showed no evidence of involvement by any of the lymphoma-associated oncogene/breakpoint regions studied. EBV genome was detected in two sBTs and in one nBT, and thus was not a distinguishing feature. These results indicate that the subtle histologic differences that distinguish subcategories of SNCL are significant biologically and reflect distinct molecular mechanisms of lymphomagenesis. Furthermore, the data suggest that the nBTs comprise a heterogeneous group with respect to their molecular genetic composition and confirm the remarkable molecular genetic homogeneity of the sBT group.

Topics: Adolescent; Adult; Blotting, Southern; Burkitt Lymphoma; Child; Child, Preschool; Chromosome Aberrations; Cyclin D1; DNA; DNA, Viral; Female; Gene Rearrangement; Genes, Immunoglobulin; Genes, myc; Herpesvirus 4, Human; Humans; Immunoglobulin M; Male; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Translocation, Genetic