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Biomedical subjects

C M Croce

Publications and source records attributed to C M Croce.

At least 199 records · Page 11Linked to original sources
PubMed1994

Suppression of tumorigenicity of breast cancer cells by microcell-mediated chromosome transfer: studies on chromosomes 6 and 11.

Development of breast cancer has been associated with deletions at multiple chromosomal regions, including 6q, 11p, and 11q. In this study we analyzed the effects of the introduction of chromosomes 6 and 11 on the cell phenotype of the breast cancer cell lines MDA-MB-231 and MCF-7. Chromosome 6 induced alterations of in vitro growth properties and suppressed tumorigenicity of MDA-MB-231 cells. Spontaneous reduction of the transferred chromosome allowed mapping of the tumor suppressor gene(s) to region 6q21-q23 and/or 6q26-q27. Clones MCF-7/H6 underwent a senescence process that lasted five months. Chromosome 11 had no effect on MDA-MB-231 cells, although it suppressed tumorigenicity of MCF-7 cells. A MCF-7/H11 clone lacking the short arm of the transferred chromosome retained tumorigenicity, however, tumor cell growth was significantly reduced. These results suggest that each chromosomal arm may contain genes important for the suppression of MCF-7 tumorigenic properties.

Breast Neoplasms↗
PubMed1994

Molecular rearrangement of the ALL-1 gene in acute myeloid leukemia without cytogenetic evidence of 11q23 chromosomal translocations.

Translocations which involve chromosome band 11q23 are frequently found in infants and adults with acute myeloid leukemia (AML) or acute lymphoblastic leukemia. We previously cloned a gene called ALL-1 which spans the 11q23 breakpoint and is rearranged in most cases of leukemia with 11q23 abnormalities. In the present report, we have investigated the occurrence of ALL-1 rearrangement in cases of AML without cytogenetic evidence of 11q23 abnormalities. We detected molecular rearrangements of the ALL-1 gene in 3 of 4 patients with de novo AML and trisomy 11 as a sole chromosomal abnormality. Furthermore, we found DNA rearrangements of ALL-1 in 2 of 19 patients with de novo AML and normal cytogenetics. We conclude that molecular rearrangement of ALL-1 often can be detected in de novo AML, despite the absence of cytogenetic abnormalities involving 11q23.

Acute Disease↗
PubMed1994

Purification and characterization of the bcl-2 protein.

The oncogene product bcl-2 functions as a repressor of programmed cell death and is a 26-kDa protein with a single predicted transmembrane segment located at the carboxyl terminus. The bcl-2 protein seems to function in different subcellular compartments, as evidenced by several biochemical and ultrastructural studies. The present study was performed to purify bcl-2 protein in significant quantities necessary for structural and functional studies. For this purpose, the bcl-2 gene was over-expressed in either baculovirus system or lymphocytes. Initially, attempts were undertaken to purify bcl-2 protein using conventional methods such as ion exchange or gel filtration chromatography. During these purification attempts we determined that bcl-2 protein is highly hydrophobic and prone to aggregation as might be expected for an integral membrane protein. By ion exchange and gel filtration chromatography, this protein could be partially purified. In order to purify bcl-2 to apparent homogeneity and avoid the aggregation problem, we prepared immunoaffinity columns using a monoclonal antibody developed against a synthetic peptide chosen from residues 61-76 of the amino acid sequence of human bcl-2. The antibody was either coupled to CNBr-activated Sepharose 4B or cross-linked into protein A-Sepharose by dimethylpimelimidate dihydrochloride. Cellular extract equivalent to 10(8) bcl-2-overexpressing insect cells or lymphocytes was applied to immunoaffinity columns. Approximately 500 micrograms purified bcl-2 protein could be recovered as estimated by silver staining and immunoblotting. Furthermore, purified bcl-2 protein was electroporated into Pre-B lymphocytes which do not express this protein in sufficient quantity to delay the onset of glucocorticoid-induced apoptosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Cellular localization of the bcl-2 protein and response to glucocorticoid stress.

We performed immunoelectronmicroscopy, immunofluorescence and subcellular fractionation studies of insect cells (Spodopetra frugiperda or SF9) infected with recombinant baculovirus containing bcl-2 cDNA to determine the cellular localization of the bcl-2 product. Similar studies were also undertaken in pre-B cells carrying a bcl-2 gene activated by t(14;18) chromosomal translocation. By immunogold electron microscopy, bcl-2 was localized at several intracellular sites including the nuclear membrane, endoplasmic reticulum, mitochondria and plasma membrane. Immunofluorescence studies revealed the presence of the bcl-2 product throughout the cytoplasm, whereas biochemical fractionation studies indicated a similar pattern to that observed on electron microscopy. Our investigation clearly indicates that the bcl-2 product is expressed at several intracellular sites. Studies were also undertaken to determine any changes in the subcellular distribution of bcl-2 protein following glucocorticoid exposure of immature B lymphocytes. Although no major changes in the distribution of bcl-2 protein were observed, more aggregated patches of gold labelled bcl-2 particles were found under glucocorticoid stress. Aggregation of bcl-2 molecules might represent dimerization necessary to prevent apoptosis.

Journal Article↗
PubMed1994

Evolutionary conservation of the EPS8 gene and its mapping to human chromosome 12q23-q24.

We have previously isolated the coding sequence for a novel substrate for tyrosine kinases, eps8, from NIH3T3 fibroblasts. Eps8 was phosphorylated in vivo by several receptor tyrosine kinases (RTKs) and, upon overexpression, was able to enhance EGFR-mediated mitogenic signaling in NIH3T3 cells. To gain understanding of eps8 function as well as its role in normal and neoplastic proliferation, we cloned the human eps8 coding sequence and studied expression of the human RNA and protein, evolutionary conservation, and chromosomal location. In addition to a previously identified SH3 domain, the predicted amino acid sequence of human eps8 revealed a non-random distribution of prolines, clustered in a way to suggest SH3-binding sites and a putative PH domain. Eps8 was expressed in all epithelial and fibroblastic lines examined and in some, but not all, hematopoietic cells. An essential function of eps8 in cell growth regulation was underscored by its conservation during evolution, where eps8-related sequences were detected as early as in Saccharomyces cerevisiae. Finally, the human EPS8 locus was mapped to chromosome 12q23-q24.

3T3 Cells↗
PubMed1994

The human eps15 gene, encoding a tyrosine kinase substrate, is conserved in evolution and maps to 1p31-p32.

Employing an expression cloning approach for tyrosine kinase substrates, we have previously isolated the coding sequence for a novel putative EGFR substrate, eps15, from NIH3T3 fibroblasts. Eps15 displayed a receptor-specific pattern of tyrosine phosphorylation in vivo and was able to transform NIH3T3 cells upon overexpression. To gain understanding of eps15 function as well as its role in normal and neoplastic proliferation, we cloned the human eps15 coding sequence and studied expression of the human RNA and protein, evolutionary conservation, and chromosomal location. The close structural similarity of human eps15 with the murine homologue is indicated by 89% and 90% identity of nucleotide and predicted amino acid sequences, respectively. Using the human eps15 coding sequence as probe, we demonstrate that eps15 is member of a gene family that is highly conserved during evolution. An essential function of eps15 in cell growth regulation is underscored by our observation of ubiquitous expression at the transcript and the protein level in normal and malignant human cells. The human EPS15 locus maps to chromosome 1p31-p32, a region involved in deletion in neuroblastoma, translocations in acute lymphoblastic leukemia, and exhibiting a fragile site.

3T3 Cells↗
PubMed1993

Chromosome walking on the TCL1 locus involved in T-cell neoplasia.

The TCL1 locus on chromosome 14 band q32.1 is frequently involved in the chromosomal translocations and inversions with the T-cell receptor genes observed in several T-cell tumors, including T-prolymphocytic leukemias, acute and chronic leukemias associated with the immunodeficiency syndrome ataxia-telangiectasia, and adult T-cell leukemia. All breakpoints cloned in this area have been mapped to 14q32.1, an area distant approximately 10,000 kb from the immunoglobulin heavy-chain gene locus on chromosome 14q band 32.3. Except for two cases of inversion, no physical linkage of the cloned breakpoints has been reported, nor has a gene been identified in this region. Taking advantage of chromosome-walking techniques and of the P1 phage, we cloned and characterized 450 kb of the germ-line TCL1 locus, starting from the breakpoints of two independent T-cell leukemias. We show that all molecular rearrangements characterized so far map to these clones, indicating not only that this region is the target of chromosomal rearrangements occurring in this area but also that both inversion and translocations occur within a 300-kb region in the T-cell leukemias. In the attempt to identify a candidate oncogene responsible for the malignant transformation, a CpG island centromeric to the inversions and to the translocations has been identified. Two probes near the CpG island have detected sequences conserved among species, as well as two transcripts in the K562 human erythroleukemia cell line. On the basis of these data, a model of activation of the putative TCL1 oncogene is suggested.

Base Sequence↗
PubMed1993

Potential topoisomerase II DNA-binding sites at the breakpoints of a t(9;11) chromosome translocation in acute myeloid leukemia.

We have examined a t(9;11)(p22;q23) chromosome translocation in an acute myeloid leukemia of an infant. The breakpoints on the two chromosomes occurred within introns of the involved genes: AF-9 on chromosome 9, and ALL-1 on chromosome 11. Sequence analysis identified heptamers flanking the breakpoints on both chromosomes 9 and 11, suggesting that the V-D-J recombinase was involved in the translocation. The presence of an N-region between the two chromosomes supports the hypothesis that a mistake in V-D-J joining was involved in the genesis of the translocation and indicates that terminal deoxynucleotidyl transferase was expressed in the cells from which this acute myeloid leukemia originated. In addition, potential topoisomerase II DNA-binding sites were found near the breakpoints of both chromosomes, suggesting the involvement of altered topoisomerase II activity in this translocation. Altered topoisomerase II activity in the presence of an active V-D-J recombinase may be a pathogenetic mechanism of acute myeloid leukemia with rearrangements at 11q23.

Amino Acid Sequence↗
PubMed1993

Molecular analysis of the BCL-3 locus at chromosome 17q22 in B-cell neoplasms.

To better understand the role of the BCL-3 locus at chromosome 17q22 in the pathogenesis and progression of leukemias and lymphomas, we examined its genomic configuration in 264 B-cell malignancies and its expression in a smaller subset. Cases studied included 39 chronic lymphocytic leukemias, 58 low-grade follicular lymphomas, 20 mantle cell lymphomas, 30 small noncleaved cell lymphomas, 25 acute lymphoblastic leukemias, 10 acquired immunodeficiency syndrome--related non-Hodgkin's lymphomas, and 44 diffuse mixed- or diffuse large-cell lymphomas. In addition, 38 aggressive lymphomas (transformed follicular lymphomas) derived from previously indolent follicular lymphomas were examined. Southern blot analysis showed BCL-3 locus rearrangement in 4 cases (1.5%), ie, in 3 transformed follicular lymphomas and in 1 indolent follicular lymphoma. All 4 also had BCL-2 rearrangements consistent with their follicular center cell origin. None of the BCL-3 rearranged cases showed MYC gene rearrangement, as reported for the original leukemia that led to the discovery of BCL-3. Pretransformation specimens of all three transformed follicular lymphomas showed the presence of the BCL-3 alteration before histologic progression. In 1 case, serial pretransformation biopsies showed that the BCL-3 rearrangement was acquired during the indolent follicular phase of the patient's disease. Thirty lymphomas, including 2 of the 4 with BCL-3 rearrangement, were also examined for BCL-3 message. All 30, including the 2 with BCL-3 rearrangements, expressed the normal 1.7-kb BCL-3 transcript, at approximately equivalent levels. The data indicate that, although BCL-3 locus alterations are found in only a small fraction of B-cell lymphoid malignancies, they occur primarily in a subset of follicular center cell lymphomas. Interestingly, these alterations appear to be acquired during the indolent (follicular) phase of the disease and they are maintained when histologic transformation takes place. The data also suggest that BCL-3 locus alterations do not result in gross changes of BCL-3 gene expression and do not necessarily involve the MYC gene. Although the preferential involvement of BCL-3 alterations in a small subset of follicular lymphomas that transform suggests a possible link between these abnormalities and progression, further studies are needed to ensure that these alterations are biologically relevant and not simply a manifestation of genomic instability.

B-Cell Lymphoma 3 Protein↗
PubMed1993

Southern blot analysis of ALL-1 rearrangements at chromosome 11q23 in acute leukemia.

The chromosome 11q23 band is a genetic region frequently involved in nonrandom karyotypic abnormalities of acute leukemia. A genomic locus named ALL-1 or MLL, where 11q23 breakpoints are clustered, has been recently cloned and characterized. We have made use of an ALL-1-specific probe in Southern blot experiments to analyze the configuration of this gene in a large series of acute leukemia patients, representative of all different myeloid and lymphoid subtypes. Nine of 145 cases (6.2%) showed abnormal ALL-1 restriction fragments in leukemic DNAs. Of these nine cases, five patients in whom karyotypic data were available displayed chromosome 11q23 aberrations, including t(4;11) (three cases) and t(9;11) (two cases). Immunophenotypic and morphocytochemical characterization of ALL-1-rearranged acute leukemia revealed prevalence of poorly differentiated B lymphoid and/or monoblastic features. Considering the whole series, ALL-1 rearrangements were significantly associated with female sex, higher white blood cell counts at presentation, and very poor clinical outcome. The presence of residual disease was molecularly documented in one case at the time of clinical remission after induction treatment and was followed by early relapse. We conclude that ALL-1 rearrangements are new molecular markers of human leukemia with considerable diagnostic and prognostic relevance.

Acute Disease↗
PubMed1993

Oncogenes and signal transduction.

Cancer biologists now have a unified concept to guide their search for specific genetic abnormalities and new therapeutic approaches: The genes and proteins that participate in the conversion of normal into malignant cells are also involved in the key process that converts extracellular signals into intracellular events that culminate in division and growth.

Animals↗
PubMed1993

ALL-1 gene at chromosome 11q23 is consistently altered in acute leukemia of early infancy.

Early infancy (< 1 year of age), massive tumor cell burden, and extremely poor prognosis are characteristic features of a particular subset of childhood acute leukemias (AL). In these cases, chromosome aberrations at the 11q23 band are the most frequently reported cytogenetic abnormalities. We have recently cloned a genetic locus named ALL-1, in which DNA breakpoints are clustered in leukemic patients with 11q23 aberrations. Analysis of the ALL-1 genomic configuration in DNA from 15 infants with AL showed specific ALL-1 rearrangements in 12 cases (80%), including 5 with normal karyotypes. These findings indicate that a consistent genetic defect underlies this particular leukemic subset.

Acute Disease↗
PubMed1993

Analysis of the murine All-1 gene reveals conserved domains with human ALL-1 and identifies a motif shared with DNA methyltransferases.

A series of translocation break points found in a subset of human acute leukemias have one of the breaks on human chromosome 11q23. This region has recently been cloned and a large gene, ALL-1, with homology to the Drosophila trithorax gene has been identified. This paper describes the cloning, sequencing, and mapping of the mouse homolog of ALL-1. We have found a motif present in All-1 that shows homology to the zinc-binding domain of DNA (cytosine-5) methyltransferases (EC 2.1.1.63). Sequence analysis of the murine All-1 gene has identified distinct regions of homology with the human ALL-1 gene; these highly conserved domains may define regions of functional significance in mammals. In addition, we have identified alternatively spliced forms of All-1 within one of the zinc-finger domains, suggesting that there may be different targets and/or functions for All-1 proteins. Finally, we report that All-1 resides in the proximal portion of mouse chromosome 9 and is a candidate for a mutation that results in skeletal transformations during embryonic development.

Alternative Splicing↗
PubMed1993

Common region of ALL-1 gene disrupted in epipodophyllotoxin-related secondary acute myeloid leukemia.

Translocations at chromosomal band 11q23 characterize most de novo acute lymphoblastic leukemias (ALL) of infants, acute myeloid leukemias (AML) of infants and young children, and secondary AMLs following epipodophyllotoxin exposure. The chromosomal breakpoints at 11q23 have been cloned from isolated cases of de novo ALL and AML. Using an 859-base pair BamHI fragment of human ALL-1 complementary DNA that recognizes the genomic breakpoint region for de novo ALL and AML, we investigated two cases of secondary AML that followed etoposide-treated primary B-lineage ALL. In the first case, the translocation occurred between chromosomes 9 and 11 and the breakpoint at 11q23 localized to the same 9-kilobase region of the ALL-1 gene that is disrupted in most of the de novo leukemias. In the second case the translocation was between chromosomes 11 and 19. The breakpoint occurred outside of the ALL-1 breakpoint cluster region.

Child, Preschool↗
PubMed1993

Characterization of human bone marrow-derived closed circular DNA clones.

Because of interest in mechanisms of recombination involved in chromosomal deletions in neoplastic disease, and their relation to possible rearrangements in normal tissues, we are studying circular DNA molecules from human tissue with a long-term goal of investigating them as possible by-products of physiologically relevant intrachromosomal recombination events. Covalently closed circular (ccc) DNA from human bone marrow was cloned in bacteriophage vectors, and fourteen clones chosen randomly from the cccDNA-derived library were characterized. Five clones originated from chromosome-specific centromeric alpha-satellite DNA; two clones carried highly repetitive sequences probably derived from interspersed repetitive elements; six clones were derived from single-copy chromosome-specific sequences which detected homologous rodent sequences; and one clone (EPM10) was derived from a small chromosome 11-specific sequence family which localized to chromosome regions 11cen and 11q14. Oligonucleotide primers derived from the cccDNA clones were used in polymerase chain reaction studies to show that (1) the EPM10 clone carried the circular junction, (2) several of the single-copy products could be detected in three different bone marrow cccDNA preparations, and (3) the Alu-PCR profile for bone marrow cccDNA showed distinct bands which were similar in four bone marrow cccDNA preparations.

Acute Disease↗
PubMed1993

Chromosomal localization of four human zinc finger cDNAs.

cDNA clones encoding zinc finger motifs were isolated by screening human placenta and T-cell (Peer) cDNA libraries with zinc finger (ZNF) consensus sequences. Unique cDNA clones were mapped in the human genome by rodent-human somatic cell hybrid analysis and in some cases in situ chromosomal hybridization. ZNF80 mapped to 3p12-3qter, ZNF7 was previously mapped to 8q24 and is here shown by in situ hybridization and use of appropriate hybrids to map telomeric to the MYC locus. ZNF79 mapped to 9q34 centromeric to the ABL gene and between a constitutional chromosomal translocation on the centromeric side and the CML specific ABL translocation on the telomeric side. ZNF77 mapped to 19p while ZNF78L1 (pT3) mapped to 19q. Chromosome 19 carries many ZNF loci and other genes with zinc finger encoding motifs; the pT3 clone additionally detected a locus designated ZNF78L2, which mapped to chromosome region 1p, most likely in the region 1p32 where the MYCL and JUN loci map.

Amino Acid Sequence↗
PubMed1993

Chromosomal translocations in leukaemia.

Many haematologic malignancies carry characteristic chromosomal translocations, which are thought to play an important role in the pathogenesis of these tumours. The t(8; 14) translocation in Burkitt's lymphoma was one of the first characterized at the molecular level. In this translocation the c-myc oncogene at chromosome 8q24 becomes deregulated by enhancer elements of the immunoglobulin heavy chain locus at chromosome 14q32 leading to a very aggressive B cell malignancy. Translocations involving an overexpressed c-myc gene are also found in AIDS-associated lymphoma or in T cell leukaemias, or they develop during tumour progression of a low grade B cell malignancy into a high grade B cell tumour in an additional cytogenetic change. A different mechanism of oncogene activation in a leukaemia specific chromosomal abnormality is found for CML, where c-abl sequences are fused into the bcr locus, or in the t(4; 11) of acute childhood leukaemia involving the recently identified ALL-1 gene at chromosome 11q23 resulting in a malfunctioning, structurally altered oncogene. Thus, in the past molecular and somatic cell genetic studies have clarified many details in aetiology and progression of leukaemias and lymphomas which are useful for applications in clinical diagnostics, and which in the future will be helpful in designing a therapy based on a molecular understanding.

Burkitt Lymphoma↗