Showing papers by "Carlo M. Croce published in 1999"

ATM mutations in B-cell chronic lymphocytic leukemia

Abstract: Mutations in the ATM gene located on the long arm of chromosome 11 at 11q22-23 cause ataxia-telangiectasia, an autosomal recessive disorder that is associated with increased incidence of malignancy and, particularly, lymphoid tumors. A role for ATM in the development of sporadic T-cell chronic leukemias is supported by the finding of loss of heterozygosity at 11q22-23 and ATM mutations in leukemias carrying TCL-1 rearrangements. Approximately 14% of B-cell chronic lymphocytic leukemia (B-CLL), the most common adult leukemia, carry deletions of the long arm of chromosome 11 at 11q22-23. Loss of heterozygosity at 11q22-23 and, more recently, absence of ATM protein, have been associated with poor prognosis in B-CLL. To determine whether the ATM gene is altered in B-CLL, we have sequenced individual ATM exons in six B-CLL cases. We show that the ATM gene is mutated in a fraction of B-CLLs and that mutations can be present in the germ line of patients, suggesting that ATM heterozygotes may be predisposed to B-CLL.

The expression of a truncated HMGI-C gene induces gigantism associated with lipomatosis.

Abstract: Rearrangements of the HMGI-C gene have frequently been detected in human benign tumors of mesenchymal origin, including lipomas. The HMGI-C protein has three AT-hook domains and an acidic COOH-terminal tail. The HMGI-C modifications consist in the loss of the C-tail and the fusion with ectopic sequences. Recent results show that the loss of the COOH-terminal region, rather than the acquisition of new sequences, is sufficient to confer to HMGI-C the ability to transform NIH3T3 cells. Therefore, transgenic mice carrying a HMGI-C construct (HMGI-C/T), containing only the three AT-hook domains, were generated. The HMGI-C/T mice showed a giant phenotype, together with a predominantly abdominal/pelvic lipomatosis, suggesting a pivotal role of the HMGI-C truncation in the generation of human lipomas.

The FEZ1 gene at chromosome 8p22 encodes a leucine-zipper protein, and its expression is altered in multiple human tumors

Abstract: Alterations of human chromosome 8p occur frequently in many tumors. We identified a 1.5-Mb common region of allelic loss on 8p22 by allelotype analysis. cDNA selection allowed isolation of several genes, including FEZ1. The predicted Fez1 protein contained a leucine-zipper region with similarity to the DNA-binding domain of the cAMP-responsive activating-transcription factor 5. RNA blot analysis revealed that FEZ1 gene expression was undetectable in more than 60% of epithelial tumors. Mutations were found in primary esophageal cancers and in a prostate cancer cell line. Transcript analysis from several FEZ1-expressing tumors revealed truncated mRNAs, including a frameshift. Alteration and inactivation of the FEZ1 gene may play a role in various human tumors.

Cancer-specific chromosome alterations in the constitutive fragile region FRA3B

Abstract: We have sequenced 870 kilobases of the FHIT/FRA3B locus, from FHIT intron 3 to intron 7. The locus is AT rich (61.5%) and Alu poor (6.2%), and it apparently does not harbor other genes. In a detailed analysis of the 308-kilobase region between FHIT exon 5 and the telomeric end of intron 3, a region known to encompass a human papillomavirus-16 integration site and two clusters of aphidicolin-induced chromosome 3p14.2 breakpoints, we have precisely mapped 10 deletion and translocation endpoints in cancer-derived cell lines relative to positions of specific repetitive elements, regions of high genome flexibility and aphidicolin-induced breakpoints. Conclusions are (i) that aphidicolin-induced breakpoint clusters fall close to high-flexibility sequences, suggesting that these sequences contribute directly to aphidicolin-induced fragility; (ii) that 9 of the 10 FHIT allelic deletions in cancer cell lines resulted in loss of exons, with 7 deletion endpoints near long interspersed nuclear elements or long terminal repeat elements; and (iii) that cancer-specific deletions encompass multiple high-flexibility genomic regions, suggesting that fragile breaks may occur at these regions, whereas repair of the breaks involves homologous pairing of flanking sequences with concomitant deletion of the damaged fragile sequence.

hMSH5: A Human MutS Homologue That Forms a Novel Heterodimer with hMSH4 and Is Expressed during Spermatogenesis

Abstract: MutS homologues have been identified in nearly all organisms examined to date. They play essential roles in maintaining mitotic genetic fidelity and meiotic segregation fidelity. MutS homologues appear to function as a molecular switch that signals genomic manipulation events. Here we describe the identification of the human homologue of the Saccharomyces cerevisiae MSH5, which is known to participate in meiotic segregation fidelity and crossing-over. The human MSH5 (hMSH5) was localized to chromosome 6p22-21 and appears to play a role in meiosis because expression is induced during spermatogenesis between the late primary spermatocytes and the elongated spermatid phase. hMSH5 interacts specifically with hMSH4, confirming the generality of functional heterodimeric interactions in the eukaryotic MutS homologue, which also includes hMSH2-hMSH3 and hMSH2-hMSH6.

FHIT Loss of Function in Human Primary Breast Cancer Correlates with Advanced Stage of the Disease

Abstract: The FHIT gene, encompassing the FRA3B fragile site at chromosome 3p14.2, is a tumor suppressor gene involved in different tumor types. We have assessed 29 human primary breast carcinomas for both the presence of abnormal FHIT transcripts and the Fhit protein levels as compared with the normal breast epithelium of the same patients. In addition, we have also examined a second retrospective series of 156 consecutive breast carcinomas for the expression of the Fhit protein. In nine (31%) cases of the first series, FHIT transcripts were either aberrant or absent as determined by reverse transcription-PCR, and Fhit protein levels in tumors were low or absent as determined immunohistochemically. In 11 other cases (38%), only normal FHIT transcripts were detected by PCR, paralleled by the reduction or absence of Fhit protein. In the remaining nine cases (31%), the presence of the normal FHIT transcript corresponded to protein levels that were similar in tumor and normal breast epithelia. Thus, alterations in FHIT transcripts were detected in 31% of the patients, but reduction or absence of Fhit protein occurred in 69% of the breast carcinoma samples examined. These data suggest that alteration in Fhit expression in breast carcinomas is a frequent event. Analysis of correlation between Fhit expression and pathological, clinical, and biological parameters in these 29 tumors and in a second retrospective series of 156 consecutive primary breast carcinomas indicated that a decrease or an absence of Fhit protein expression is associated with high proliferation and large tumor size.

Abnormalities at 14q32.1 in T cell malignancies involve two oncogenes

Abstract: The TCL1 oncogene on human chromosome 14q32.1 is involved in the development of T cell leukemia in humans. Its expression in these leukemias is activated by chromosomal translocations and inversions at 14q32.1. Here we report the isolation and characterization of a new member of the TCL1 gene family, TCL1b, located ≈16 kb centromeric of TCL1. The 1.2-kb TCL1b cDNA encodes a 14-kDa protein of 128 aa and shows 60% similarity to Tcl1. Expression profiles of TCL1 and TCL1b genes are very similar: both genes are expressed at very low levels in normal bone marrow and peripheral lymphocytes but are activated in T cell leukemia by rearrangements of the 14q32.1 region. Thus, translocations and inversions at 14q32.1 in T cell malignancies involve two oncogenes.

Trithorax and ASH1 interact directly and associate with the trithorax group-responsive bxd region of the Ultrabithorax promoter.

Abstract: Trithorax (TRX) and ASH1 belong to the trithorax group (trxG) of transcriptional activator proteins, which maintains homeotic gene expression during Drosophila development. TRX and ASH1 are localized on chromosomes and share several homologous domains with other chromatin-associated proteins, including a highly conserved SET domain and PHD fingers. Based on genetic interactions between trx and ash1 and our previous observation that association of the TRX protein with polytene chromosomes is ash1 dependent, we investigated the possibility of a physical linkage between the two proteins. We found that the endogenous TRX and ASH1 proteins coimmunoprecipitate from embryonic extracts and colocalize on salivary gland polytene chromosomes. Furthermore, we demonstrated that TRX and ASH1 bind in vivo to a relatively small (4 kb) bxd subregion of the homeotic gene Ultrabithorax (Ubx), which contains several trx response elements. Analysis of the effects of ash1 mutations on the activity of this regulatory region indicates that it also contains ash1 response element(s). This suggests that ASH1 and TRX act on Ubx in relatively close proximity to each other. Finally, TRX and ASH1 appear to interact directly through their conserved SET domains, based on binding assays in vitro and in yeast and on coimmunoprecipitation assays with embryo extracts. Collectively, these results suggest that TRX and ASH1 are components that interact either within trxG protein complexes or between complexes that act in close proximity on regulatory DNA to maintain Ubx transcription. The control of body segment identity in many organisms is achieved in large part by the activities of homeotic genes. In Drosophila, the combined activities of the transiently expressed segmentation genes initiate the pattern of expression of the homeotic genes at the blastoderm stage, and additional factors and mechanisms are required to preserve these patterns at later stages of development. Two groups of genes, the trithorax group (trxG) (reviewed in reference 12) and the Polycomb group (PcG) (reviewed in references 2, 18, and 24) play major roles in the maintenance of the active and the repressed state, respectively. It is thought that trxG and PcG proteins are assembled into multiprotein complexes, which function by maintaining either open or closed domains of chromatin structure. This chromatin association has been established for several trxG proteins. The yeast and human homologues of the Drosophila trxG proteins BRAHMA, SNR1, and MOIRA have been shown to be components of a 2-MDa yeast and human SWI-SNF chromatin remodeling complex (7, 17, 32), and a similar Drosophila complex was recently characterized (16). GAGA factor, a DNA binding protein encoded by the trxG gene Trithorax-like (10), is required for the function of another Drosophila chromatin remodeling complex, the NURF complex (30). These protein complexes possess ATP-dependent activities that facilitate the binding of other transcription fac

Exon structure and promoter identification of STIM1 (alias GOK), a human gene causing growth arrest of the human tumor cell lines G401 and RD.

Abstract: . The stromal interaction molecular 1 gene (STIM1) encodes a type I trans-membrane protein of unknown function, which induces growth arrest and degeneration of the human tumor cel

13q14 deletion in non-Hodgkin's lymphoma: correlation with clinicopathologic features

Abstract: BACKGROUND AND OBJECTIVE: 13q14 deletion frequently occurs as a single anomaly in chronic lymphocytic leukemia (CLL) with favorable prognosis. This study was performed to assess the distribution of 13q14 deletion in non-Hodgkin's lymphoma (NHL) and to analyze its correlation with salient clinicopathologic features. DESIGN AND METHODS: One hundred and twenty-five NHL were analyzed by cytogenetics and by interphase fluorescence in situ hybridization (FISH), using a 13q14 cosmid probe recognizing DNA sequences between the Rb gene and the D13S25 marker. Clinical records all patients were surveyed. RESULTS: A 13q14 rearrangement was present in the stemline in 10 patients; 15 additional cases were shown by FISH to carry 13q14 deletion in 55-90% of the interphase cells, giving a 20% overall incidence for this anomaly. Six of 44 patients had a low-grade NHL, 14/28 had mantle cell lymphoma (MCL), 5/42 had a high grade NHL (p

Genomic analysis of human and mouse TCL1 loci reveals a complex of tightly clustered genes.

Abstract: TCL1 and TCL1b genes on human chromosome 14q23.1 are activated in T cell leukemias by translocations and inversions at 14q32.1, juxtaposing them to regulatory elements of T cell receptor genes. In this report we present the cloning, mapping, and expression analysis of the human and murine TCL1/Tcl1 locus. In addition to TCL1 and TCL1b, the human locus contains two additional genes, TCL1-neighboring genes (TNG) 1 and 2, encoding proteins of 141 and 110 aa, respectively. Both genes show no homology to any known genes, but their expression profiles are very similar to those of TCL1 and TCL1b. TNG1 and TNG2 also are activated in T cell leukemias with rearrangements at 14q32.1. To aid in the development of a mouse model we also have characterized the murine Tcl1 locus and found five genes homologous to human TCL1b. Tcl1b1–Tcl1b5 proteins range from 117 to 123 aa and are 65–80% similar, but they show only a 30–40% similarity to human TCL1b. All five mouse Tcl1b and murine Tcl1 mRNAs are abundant in mouse oocytes and two-cell embryos but rare in various adult tissues and lymphoid cell lines. These data suggest a similar or complementary function of these proteins in early embryogenesis.

Bdp, a New Member of a Family of DNA-binding Proteins, Associates with the Retinoblastoma Gene Product

Abstract: We have cloned a gene, BDP, encoding a protein with homology to the retinoblastoma-binding proteins Rbp1 and Rbp2. It also has homology to DNA-binding proteins such as Bright, a B-cell-specific trans-activator, and the Drosophila melanogaster dead ringer gene product. Like MyoD, Bdp binds to the COOH-terminal region of pRb through its conserved region and to hypophosphorylated pRb. It also binds to the MAR of the immunoglobulin heavy-chain locus. Thus Bdp may contribute to the transcriptional regulation of genes involved in differentiation and tissue-specific expression.

TCL-1 protein and related methods

Abstract: The present invention relates to nucleotide sequences of TCL-1 genes and amino acid sequences of their encoded proteins, as well as derivatives and analogs thereof, and antibodies thereto. The TCL-1 gene sequence is preferentially expressed early in T and B lymphocyte differentiation. The present invention further relates to the use of TCL-1 genes and their encoded proteins as diagnostic and therapeutic reagents for the detection and treatment of disease states associated with chromosomal abnormalities.

Loss of FHIT expression in acute lymphoblastic leukemia.

Abstract: Loss of expression of the FHIT tumor suppressor gene is common in epithelial malignancies such as lung, kidney, esophageal, gastric, and cervical cancers. To assess the role of FHIT in acute leukemias, we examined 18 primary acute lymphoblastic leukemias (ALLs), 8 ALL-derived cell lines, 7 cell lines from other hematological malignancies, 14 lymphoblastoid cell lines, and 5 peripheral blood lymphocyte samples for expression of FHIT mRNA and protein by reverse transcription-PCR and Northern and Western blots. Fhit protein expression was detected in only 24% of primary ALLs and leukemia/lymphoma cell lines, but it was detected in all lymphoblastoid cell lines and peripheral blood lymphocyte samples. Interestingly, Fhit protein expression was lost in all T-cell ALLs but was lost in only half of the B-cell ALLs. Northern blotting of 7 normal lymphoblastoid cell lines and 13 of the neoplastic cell lines confirmed the results obtained by Western blotting regarding FHIT expression. The high frequency of loss of Fhit expression in ALLs suggests that inactivating alterations at the FHIT locus contribute to development of the leukemias.

Role of TCL1 and ALL1 in Human Leukemias and Development

Abstract: We have investigated the role of chromosomal translocations in the pathogenesis of human leukemias. The study of T-cell chronic lymphocytic leukemias and T-cell prolymphocytic leukemia has led to the identification of TCL1, a novel gene that is deregulated by translocations, t(14;14)(q11;q32), or inversions, inv(14)(q11;q32.1). Introduction of a human TCL1 gene juxtaposed to the Ick promoter into fertilized mouse eggs resulted in the development of transgenic mice that developed mature T-cell leukemias, indicating that TCL1 is a transforming oncogene. We have also investigated acute leukemias with abnormalities at chromosome 11q23. We have identified a gene, ALL1, that can fuse to many different genes in acute leukemias. We have also shown that ALL1 can fuse with ALL1 in acute myelogenous leukemia. We have proposed that the ALL1 fusion genes may act by a dominant negative mechanism.

Significance of FHIT expression in chronic myelogenous leukemia

Abstract: Loss or reduced expression of the fragile histidine triad ( FHIT ) gene, a tumor suppressor gene localized at chromosome 3p14.2, is common in several solid and hematological cancers and has been associated with tumor progression and worse prognosis. The role of the FHIT gene in the pathogenesis of chronic myelogenous leukemia (CML) or its progression from a chronic phase to the accelerated and blastic phases is not known. The aim of this study was to evaluate whether Fhit protein expression is altered in CML, and whether it plays any role in CML progression, disease responsiveness to therapy, or prognosis. A total of 195 patients with Philadelphia chromosome-positive CML were evaluated, including 129 patients in early chronic phase (time from diagnosis to study, 12 months or less), 30 patients in late chronic phase, and 36 patients in the accelerated and blastic phases. The levels of cellular Fhit protein expression were determined using Western blot analysis and solid-phase RIA and compared to the levels in 31 normal marrows. The median Fhit expression in normal marrows was assigned a value of 1, and the levels in CML samples were normalized to the median of the normal control. Fhit levels in CML samples were evaluated in relation to CML phase and patient characteristics and prognosis in the early chronic phase. The median Fhit value in CML samples was 0.89 (range, 0.34–2.62). Eight of the 195 (4%) CML samples showed Fhit levels P = 0.04) and lower platelet counts ( P = 0.01), but not with poorer-risk groups. No differences in response to IFN-α therapy or in survival were observed by different Fhit levels. Lack of Fhit protein expression was detected in 4% of CML cases, and reduced expression occurred in a subpopulation of patients. However, reduced Fhit expression is not associated with progression, response to therapy, or prognosis in CML.

Advances in cancer cytogenetics.

Abstract: As the end of the millenium approaches, recognition of the milestones achieved in the field of cancer cytogenetics is mandatory. With regard to cancer cytogenetics, the turning century can be divided in three main era: the pre-banding period that has posed important hypothesis and technical premises, the fruitful banding era that led to the discovery of the critical chromosomal rearrangements and cloning of cancer genes and the more recent revolutionizing era of molecular cytogenetics where technological advances permit a global visualization and high-level resolution of chromosomal alterations. J. Cell. Biochem. Suppls. 32/33:173-182, 1999.

Ninth Annual Pezcoller Symposium: The Biology of Tumors

Abstract: The Ninth annual Pezcoller Symposium was held in Rovereto, Italy, on June 4 to 7, 1997, and focused on molecular mechanisms underlying the biology of tumors. The genetic mechanisms underlying heterogeneity of tumor cell populations and tumor cell differentiation were discussed. Tumor cells closely interact with host cells and cell products having different functions, and these interactions play an important role in the biology of tumors. Interactions between tumor cells and cells of host defenses were discussed, with particular emphasis on the molecular basis of tumor recognition by the immune system. Interactions between cells were also discussed with reference to molecular mechanisms of cell regulation that are affected by or implemented through these interactions. The mechanisms of tumor vascularization were also discussed: without suitable angiogenesis, the tumor cannot grow and metastasize. Angiogenesis also provides a potential site of therapeutic intervention, and this makes it even more important to understand the mechanisms underlying it. Cell regulation and cell interactions are determined by activated genes through the appropriate and timely mediation of gene products. It is becoming increasingly important to develop methodologies that would allow us to measure differentially genes and gene products and thus validate many of the mechanisms of control proposed presently.

Oncogenes and Mammary Carcinogenesis

Abstract: Breast cancer is the most common malignancy among women in the United States, accounting for nearly 32% ofall cancers and for nearly 20% ofall cancer deaths in women (1) Breast cancer is a multifactorial disease, and several factors are thought to influence the risk of breast cancer development, including geography, radiation exposure, and reproductive and family history A family history of breast cancer constitutes the major risk factor, although familial breast cancer accounts for only 5% of all cases (1) Although breast cancer deaths declined by 5% between 1989 and 1992 (2), the incidence of breast cancer is expected to increase by 2–3% annually (1), and efforts to decrease mortality significantly, including new therapeutic approaches and early diagnosis, have been relatively unsuccessful One of the critical factors in determining the therapeutic approach to breast cancer, along with the presence or absence of lymph node metastasis, is the estrogen and progesterone receptor (ER and PR) status of the tumor Indeed, ER- and/or PR-positive tumors have been found to be more likely to respond to endocrine therapy and are associated with a better prognosis (1) An understanding of the genetic changes involved in breast cancer and of its biologic behavior, including possible interactions between hormones and oncogenes or tumor suppressor genes, will undoubtedly aid in the design of new therapies as well as in prevention and diagnosis of this disease