The FHIT gene, a multiple tumor suppressor gene encompassing the carcinogen sensitive chromosome fragile site, FRA3B.
Explore the source record for details and available documents.
Acid Anhydride Hydrolases↗
Biomedical subjects
C M Croce
Publications and source records attributed to C M Croce.
Association between cigarette smoking and FHIT gene alterations in lung cancer.
Epidemiologic data have strongly indicated that cigarette smoking is linked to the development of lung cancer. However, little is known of the molecular targets of carcinogens contained in tobacco smoke. To identify genetic lesions characteristic of tobacco damage, we undertook a molecular analysis of microsatellite alterations within the FHIT gene and FRA3B, as well as at an independent locus on chromosome 10, D10S197, in lung tumors from heavy smokers and in tumors from never smokers. Loss of heterozygosity affecting at least one locus of the FHIT gene was observed in 41 of 51 tumors in the smokers group (80%) but in only 9 of 40 tumors in nonsmokers (22%). The comparison between the frequency of losses in FHIT in smokers and nonsmokers was statistically significant (P = 0.0001), whereas no difference in loss of heterozygosity rate was observed at D10S197 locus. These findings suggest that FHIT is a candidate molecular target of carcinogens contained in tobacco smoke.
Acid Anhydride Hydrolases↗
The human ALL-1/MLL/HRX antigen is predominantly localized in the nucleus of resting and proliferating peripheral blood mononuclear cells.
The ALL-1 gene is an important regulator of embryonal and hematopoietic development, and structural variants of the human gene generated by chromosomal translocations and other genomic alterations presumably act as oncogenes in the pathogenesis of acute leukemias and other hematological malignancies. Antisera against two different epitopes of the human ALL-1 protein (anti-ALL1-N and anti-ALL1-C) were produced. Both sera revealed indistinguishable patterns of antigen localization in human peripheral blood mononuclear cells (PBMCs). In resting PBMCs, the antigen was distributed in a speckled pattern across the nuclei, with an increased density at the nuclear envelope and the nuclear indentation. In mitotically stimulated PBMCs, the antigen surrounded the condensing chromosomes but did not colocalize with chromatin or the nuclear scaffold. The antigen is considered a marker for a novel nuclear subcompartment, a perichromosomal area termed the "chromosomal envelope." In Western blot experiments, the anti-ALL1-N serum reacted with a polypeptide corresponding to the expected full-length 430-kDa ALL-1 protein. Recombinant proteins representing the AT-hook and zinc binding subdomains of the ALL-1 protein interacted in vitro with a degenerate mixture of double-stranded oligodeoxynucleotides. Thus, the ALL-1 protein probably is a DNA-binding protein with both a sequence-unspecific (AT-hook) and a sequence-specific (zinc binding subdomains) double-stranded DNA binding mode.
Animals↗
Cytogenetic and interphase cytogenetic characterization of atypical chronic lymphocytic leukemia carrying BCL1 translocation.
Conventional chromosome analysis (CCA) and fluorescent in situ hybridization (FISH) studies, using a 390-kb yeast artificial chromosome probe spanning the area of multiple breakpoints of the BCL1 locus at 11q13, were performed on 57 patients fulfilling the French-American-British criteria for the diagnosis of atypical B-cell chronic lymphocytic leukemia (CLL). To better define the incidence of 13q deletions and trisomy 12, FISH analysis was also performed using a cosmid probe that recognized a DNA sequence between the Rb gene and the D13S25 locus at band 13q14 and a chromosome 12-specific pericentromeric probe. All patients were characterized by cytoimmunological and hematological studies. Fourteen cases displayed three fluorescent signals in 41-98% interphase cells when hybridized to the BCL1 yeast artificial chromosome probe, documenting the presence of BCL1 translocation (BCL1-positive cases). The presence of t(11;14)(q13;q32) was ascertained in 12 cases using CCA and by dual color interphase FISH using the BCLI probe and a 14q telomere probe in 2 karyotypically normal cases. The remaining 43 cases had two signals in more than 95% interphase cells (BCL1-negative) and did not have the t(11;14) at CCA. Although 13q14 deletions were seen by means of CCA in only 5 of 14 BCL1-positive cases, hemizygous or homozygous deletions at band 13q14 were detected by FISH in 11 of 14 BCL1-positive cases, as compared with 17 of 43 BCL1-negative cases (P = 0.01). A subclone with trisomy 12 in addition to BCL1 translocation and del(13q14) was present in four BCL1-positive cases. We arrived at the following conclusions: (a) FISH with this BCL1 YAC probe is an efficient method for the detection of the t(11;14) and of the corresponding involvement of the BCL1 locus in this lymphoproliferative disorder; (b) the majority of BCL1-positive atypical CLLs by French-American-British criteria may carry 13q14 deletions; (c) the recognition of this cytogenetic subset of atypical CLL, sharing some immunological and cytogenetic features with mantle cell lymphoma, may be important, because these patients usually present isolated peripheral blood and marrow lymphocytosis, with or without mild to moderate spleen involvement, and may require early cytotoxic treatment.
Chromosomes, Artificial, Yeast↗
Positions of chromosome 3p14.2 fragile sites (FRA3B) within the FHIT gene.
The FHIT gene spans approximately 1 Mb of DNA at chromosome band 3p14.2, which includes the familial renal cell carcinoma chromosome translocation breakpoint (between FHIT exons 3 and 4), the most frequently expressed human constitutive chromosomal fragile site (FRA3B, telomeric to the t(3;8) translocation), and numerous homozygous deletions in various human cancers, frequently involving FHIT exon 5. The FRA3B has previously been shown to represent more than one specific site, and some specific representatives of FRA3B breaks have been shown to fall in two regions, which we know to be in FHIT introns 4 and intron 5. Because breakage and integration of exogenous DNA in this chromosome region is frequent in aphidicolin-treated somatic cell hybrids, cancer cells, and, presumably, aphidicolin-treated normal lymphocytes that exhibit gaps or breaks, we determined by one- and two color fluorescence in situ hybridization, using cosmids covering specific regions of the FHIT gene, that most of the aphidicolin-induced gaps at FRA3B fall within the FHIT gene, with the highest frequency of gaps falling in intron 5 of the FHIT gene, less than 30 kb telomeric to FHIT exon 5. Gaps also occur in intron 4, where a human papillomavirus 16 integration site has been localized, and in intron 3, where the t(3;8) break point is located. These results suggest that the cancer-specific deletions, which frequently involve introns 4 and 5, originated through breaks in fragile sites.
Acid Anhydride Hydrolases↗
A potential role for interleukin-15 in the regulation of human natural killer cell survival.
Resting lymphocyte survival is dependent upon the expression of Bcl-2, yet the factors responsible for maintaining lymphocyte Bcl-2 protein expression in vivo are largely unknown. Natural killer (NK) cells are bone marrow-derived lymphocytes that constitutively express the beta and common gamma(c) subunits of the IL-2 receptor (R) as a heterodimer with intermediate affinity for IL-2. IL-15 also binds to IL-2Rbeta gamma(c) and is much more abundant in normal tissues than IL-2. Mice that lack the IL-2 gene have NK cells, whereas mice and humans that lack IL-2R gamma(c) do not have NK cells. Further, treatment of mice with an antibody directed against IL-2Rbeta results in a loss of the NK cell compartment. These data suggest that a cytokine other than IL-2, which binds to IL-2Rbeta gamma(c), is important for NK cell development and survival in vivo. In the current report, we show that the recently described IL-15R(alpha) subunit cooperates with IL-2Rbeta gamma(c) to transduce an intracellular signal at picomolar concentrations of IL-15. We demonstrate that resting human NK cells express IL-15R(alpha) mRNA and further, that picomolar amounts of IL-15 can sustain NK cell survival for up to 8 d in the absence of serum. NK cell survival was not sustained by other monocyte-derived factors (i.e., TNF-alpha, IL-1beta, IL-10, IL-12) nor by cytokines known to use gamma(c) for signaling (i.e., IL-4, IL-7, IL-9, IL- 13). One mechanism by which IL-15 promotes NK cell survival may involve the maintenance of Bcl-2 protein expression. Considering these functional properties of IL-15 and the fact that it is produced by bone marrow stromal cells and activated monocytes, we propose that IL-15 may function as an NK cell survival factor in vivo.
Animals↗
The localization of the HRX/ALL1 protein to specific nuclear subdomains is altered by fusion with its eps15 translocation partner.
Translocations involving the HRX/ALL1 locus at chromosomal region 11q23 are among the most frequent cytogenetic abnormalities in acute leukemias. 11q23 translocations involve different chromosome partners and lead to the formation of HRX/ALL1 fusion proteins. The HRX/ALL1 protein is a putative transcription factor that has been implicated in developmental regulation in mammals. We report here the cellular localization of the HRX/ALL1 protein as well as that of the HRX/ALL1-eps15 fusion protein, the result of the t(1;11) (p32-q23) translocation of acute myeloid leukemias. The HRX/ALL1 protein was localized to both the cytoplasm and the nucleus. The nuclear pattern was characterized by diffuse staining, perinuclear accumulation, and localization within nuclear bodies of variable size, morphology, and number. The HRX/ALL1-eps15 localized exclusively to the nucleus within bodies that were smaller and more numerous than the HRX/ALL1 nuclear bodies. HRX/ALL1 fusion with an unknown partner in leukemia blasts with 11q23 abnormalities had similar morphological features. Thus, the fusion with eps15 alters the cellular compartmentalization of HRX/ALL1, providing a putative mechanism for activation of HRX/ALL1 by 11q23 abnormalities.
Adaptor Proteins, Signal Transducing↗
Structure and expression of the human FHIT gene in normal and tumor cells.
The FHIT gene, encoded by 10 exons in a 1.1-kb transcript, encompasses approximately 1 Mb of genomic DNA, which includes the hereditary RCC t(3;8) translocation break at 3p14.2, the FRA3B common fragile region, and homozygous deletions in various cancer-derived cell lines. Because some of these genetic landmarks (e.g., the t(3;8) break between untranslated FHIT exons 3 and 4, a major fragile region that includes a viral integration site between exons 4 and 5, and cancer cell homozygous deletions in intron 5) do not necessarily affect coding exons and yet apparently affect expression of the gene product, we examined the FHIT locus and its expression in detail in more than 10 tumor-derived cell lines to clarify mechanisms underlying aberrant expression. We observed some cell lines with apparently continuous large homozygous deletions, which included one or more coding exons; cell lines with discontinuous deletions, some of which included or excluded coding exons; and cell lines that exhibited heterozygous and/or homozygous deletions, by Southern blot analysis for the presence of specific exons. Most of the cell lines that exhibited genomic alterations showed alteration of FHIT transcripts and absence or diminution of Fhit protein.
Acid Anhydride Hydrolases↗
Bcl2 is the guardian of microtubule integrity.
We have investigated the ability of several drugs commonly used in the treatment of human cancer to induce bcl2 phosphorylation and cell death in human cell lines derived from acute leukemia, lymphoma, breast cancer, and prostate cancer. The results of this analysis indicate that drugs affecting the integrity of microtubules induce bc12 phosphorylation, whereas anticancer drugs damaging DNA do not. Comparison of the effects of taxol and its analogue, taxotere, indicates that taxotere is capable of inducing bcl2 phosphorylation and apoptotic cell death at 100-fold lower concentrations than taxol. Induction of cancer cell death through phosphorylation of bcl2 thus provides an opportunity not only for more refined targeting of therapeutic drugs but for understanding of an important pathway leading to apoptosis. Phosphorylation of bcl2 in drug-treated cancer cells occurs in G2-M, the phase of the cell cycle in which this class of drugs is active. No induction of bcl2 phosphorylation occurs in chronic lymphocytic leukemia cells that overexpress bcl2 but are blocked at G0-G1. Thus, prevention of polymerization or depolymerization of cellular microtubules by this class of cancer therapeutic drugs causes phosphorylation of bcl2, abrogating the normal antiapoptotic function of bcl2 and initiating the apoptotic program in the cycling cancer cells; these results are consistent with a normal physiological role of bcl2 as "guardian of microtubule integrity."
Antineoplastic Agents↗
BMP7 null mutation in mice: developmental defects in skeleton, kidney, and eye.
While generating bcl2 alpha transgenic mice, we found some F2 offspring of one of the transgenic lines which were very small and had closed eyes at the time of weaning. These pups died within 1 month after birth. In order to determine the molecular basis of this phenotype, we screened a genomic library of the above transgenic line with a transgene-specific probe and found that the Bmp7 gene, a member of the TGF beta superfamily, was inactivated by insertional mutagenesis due to transgene integration. The Bmp7 homozygous null condition in mice is a postnatal lethal mutation and is associated with various developmental defects: holes in the basisphenoid bone and the xyphoid cartilage, retarded ossification of bones, fused ribs and vertebrae, underdeveloped neural arches of the lumbar and sacral vertebrae, polydactyly of the hind limbs, a kinked tail, a reduced number of nephrons, polycystic kidney, lack of retinal pigmentation, and retarded lens development. These findings indicate that BMP7 is an important signaling molecule for normal development of the mammalian skeleton, kidney, and eye. Academic Press
Abnormalities, Multiple↗
Chromosome aberrations in atypical chronic lymphocytic leukemia: a cytogenetic and interphase cytogenetic study.
To define better the chromosomal profile of atypical chronic lymphocytic leukemia (aCLL), cytogenetic and interphase cytogenetic studies were performed in 43 cases, using mitogen-stimulated cultures and DNA probes detecting the two most frequently occurring aberrations in CLL, ie +12 and 13q14 deletions. All cases showed monoclonal CD5/CD19-positive lymphocytosis, with more than 10% large lymphocytes and/or prolymphocytes in peripheral blood smears and reactivity with FMC7, or bright expression of surface immunoglobulins in a fraction of the cases. Karyotype aberrations were detected in 27 of 43 cases (62.8%). Recurrent chromosome changes were +12 (nine cases), 13q14 aberrations (five cases), 11q anomalies (three cases), 6q21-q23 abnormalities and 4q anomalies with different breakpoints (two cases each). Additional chromosome changes were seen in four cases with +12, in three cases with 13q14 anomalies, in two cases with 11q anomalies, in one case with 6q and 4q anomalies. Trisomy 12 was associated with 13q14 anomalies in three cases, one of which also had an 11q abnormality; other associations, found in one case each, were: 13q14 deletion with a 6q anomaly, 11q anomaly with 13q- and 7q-, a 6q anomaly with 7q- and +12. Interphase cytogenetics confirmed the results of chromosome banding analysis and showed that six patients with normal karyotype or no mitosis in fact had concomitant +12 and 13q14 deletion in four cases and isolated +12 or 13q14 deletion in one case each, with a resultant 76% overall incidence of cytogenetic abnormalities. The presence of +12, 13q14 deletions, 11q, and 6q21-q23 anomalies in 19 cases was associated with a 2-month median interval between diagnosis and start of treatment, as compared with a 24-month median interval in 14 cases with normal karyotype or non-recurrent chromosome changes (P = 0.003). We conclude that aCLL is characterized by a relatively high incidence of chromosome anomalies, with recurrent chromosome changes, involving chromosomes 12, 13q14, 6q21q23, 11q, and, possibly, 4q. The presence of complex karyotypes, with concomitant abnormalities of 13q, +12, 6q, 11q, suggests that the development of sequential chromosome changes, rather than any single specific anomaly, may underlie leukemogenesis in this cytologic subset of CLL, partially accounting for the relatively aggressive clinical course.
Adult↗
Selective enrichment in human megakaryocyte progenitors by the B203.13 surface differentiation antigen.
The B203.13 monoclonal antibody specifically recognizes a subset (8-18.5%) of human CD34+ haemopoietic progenitors, which are significantly (P<0.05) enriched in megakaryocyte progenitors (CFU-meg). Moreover B203.13 expression was progressively lost as maturation proceeded along the megakaryocytic lineage. In fact: (i) CFU-meg derived from CD34+/B203.13+ showed a greater number of cells/colony with respect to CD34+/B203.13-; (ii) after 10 d of liquid cultures with 100 ng/ml of thrombopoietin, only a minority of CD34-derived cells positive for CD41 coexpressed B203.13; (iii) in situ immunocytochemical staining revealed that B203.13 was expressed exclusively on immature megakaryoblasts; (iv) circulating platelets did not express B203.13.
Antigens, Differentiation↗
Multigenetic lesions in infant acute leukaemias: correlations with ALL-1 gene status.
In this study we investigated the presence of structural lesions in the ALL-1, p53 and p16 (cyclin-dependent kinase 4 inhibitor) genes in leukaemic cells obtained from 22 patients with infant acute leukaemia (aged < 18 months). Of these, 18 cases were classified as acute lymphoblastic leukaemia (ALL) and four as acute myeloid leukaemia (AML). Tumour DNAs were analysed by a combination of Southern blot. polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP), and direct sequence analyses. The results showed ALL-1 gene rearrangements in 15/22 (68%) cases, p53 gene mutations in 5/22 (26%), and a homozygous deletion of p16 in a single T-ALL case. p53 and p16 alterations were all found in the group of patients with ALL-1 gene rearrangements. p53 mutations were more often associated with a myeloid phenotype (3/5). In summary, multiple molecular alterations were found in 6/15 (40%) infant acute leukaemias with ALL-1 rearrangements. As to the clinical course, patients with additional lesions had similar clinical outcome with respect to patients with ALL-1 gene rearrangement as the sole genetic aberration. This may support the hypothesis that ALL-1 alterations are genetic events per se sufficient to confer a fully malignant phenotype to the leukaemic clone.
Acute Disease↗
Purification and crystallization of complexes modeling the active state of the fragile histidine triad protein.
Fragile histidine triad protein (Fhit) is a diadenosine triphosphate (ApppA) hydrolase encoded at the human chromosome 3 fragile site which is frequently disrupted in tumors. Reintroduction of FHIT coding sequences to cancer cell lines with FHIT deletions suppressed the ability of these cell lines to form tumors in nude mice even when the reintroduced FHIT gene had been mutated to allow ApppA binding but not hydrolysis. Because this suggested that the tumor suppressor activity of Fhit protein depends on substrate-dependent signaling rather than ApppA catabolism, we prepared two crystalline forms of Fhit protein that are expected to model its biologically active, substrate-bound state. Wild-type and the His96Asn forms of Fhit were overexpressed in Escherichia coli, purified to homogeneity and crystallized in the presence and absence of ApppA and an ApppA analog. Single crystals obtained by vapor diffusion against ammonium sulfate diffracted X-rays to beyond 2.75 A resolution. High quality native synchrotron X-ray data were collected for an orthorhombic and a hexagonal crystal form.
Acid Anhydride Hydrolases↗
Ectopic TAL-1/SCL expression in phenotypically normal or leukemic myeloid precursors: proliferative and antiapoptotic effects coupled with a differentiation blockade.
The TAL-1 gene specifies a basic helix-loop-helix domain (bHLH) transcription factor, which heterodimerizes with E2A gene family proteins. tal-1 protein is abnormally expressed in the majority of T-cell acute lymphoblastic leukemias (T-ALLs). tal-1 is expressed and plays a significant role in normal erythropoietic differentiation and maturation, while its expression in early myeloid differentiation is abruptly shut off at the level of late progenitors/early differentiated precursors (G. L. Condorelli, L. Vitelli, M. Valtieri, I. Marta, E. Montesoro, V. Lulli, R. Baer, and C. Peschle, Blood 86:164-175, 1995). We show that in late myeloid progenitors (the phenotypically normal murine 32D cell line) and early leukemic precursors (the human HL-60 promyelocytic leukemia cell line) ectopic tal-1 expression induces (i) a proliferative effect under suboptimal culture conditions (i.e., low growth factor and serum concentrations respectively), via an antiapoptotic effect in 32D cells or increased DNA synthesis in HL-60 cells, and (ii) a total or marked inhibitory effect on differentiation, respectively, on granulocyte colony-stimulating factor-induced granulopoiesis in 32D cells or retinoic acid- and vitamin D3-induced granulo- and monocytopoiesis in HL-60 cells. Furthermore, experiments with 32D temperature-sensitive p53 cells indicate that aberrant tal-1 expression at the permissive temperature does not exert a proliferative effect but causes p53-mediated apoptosis, i.e., the tal-1 proliferative effect depends on the integrity of the cell cycle checkpoints of the host cell, as observed for c-myc and other oncogenes. tal-1 mutant experiments indicate that ectopic tal-1 effects are mediated by both the DNA-binding and the heterodimerization domains, while the N-terminally truncated tal-1 variant (M3) expressed in T-ALL malignant cells mimics the effects of the wild-type protein. Altogether, our results (i) indicate proliferative and antidifferentiative effects of ectopic tal-1 expression, (ii) shed light on the underlying mechanisms (i.e., requirement for the integrity of the tal-1 bHLH domain and cell cycle checkpoints in the host cell, particularly p53), and (iii) provide new experimental models to further investigate these mechanisms.
Apoptosis↗
T-cell-directed TAL-1 expression induces T-cell malignancies in transgenic mice.
The TAL-1 gene specifies for a basic domain-helix-loop-helix protein, which is involved in the control of normal hematopoiesis. In human pathology, the TAL-1 gene product is expressed in a high percentage of T-cell acute lymphoblastic leukemias in the pediatric age range; however, it has not been established whether the expression has a causal role in oncogenesis. In this report, we describe the phenotype of mouse transgenic lines obtained by inducing tal-1 protein expression in lymphoid tissues using the LCK promoter. The survival rate of tal-1 transgenic animals was much lower as compared with control mice. Histopathological analysis revealed lymphomas of T-cell type, often comprising a minor B-cell component. Some mice showed marked splenic lymphocyte depletion. Primary lymphocyte cultures showed partial independence from exogenous growth stimuli and increased resistance to low-serum apoptosis. To further unravel the tal-1 oncogenic potential, a strain of tal-1 transgenic mice was crossbred with p53-/- mice; the survival rate in these animals was reduced by more than one-half when compared with that of tal-1 mice, and histopathological analysis revealed exclusively T-cell lymphomas. These data indicate that TAL-1, expressed in T cells, is per se a potent oncogene, which may exert a key leukemogenetic role in the majority of T-cell acute lymphoblastic leukemias.
Adenovirus E2 Proteins↗
ALL-1 interacts with unr, a protein containing multiple cold shock domains.
The ALL-1 gene is involved in human acute leukemia through chromosome translocations and fusion to partner genes, or through partial tandem duplications. ALL-1 is the human homologue of Drosophila trithorax which transregulates the homeotic genes of the Antennapedia and bithorax complexes controlling body segment identity. ALL-1 encodes a very large protein of 3968 amino acids which presumably interacts with many proteins. Here we applied yeast two hybrid screening to identify proteins interacting with the N-terminal segment of ALL-1. One protein obtained in this way was the product of the unr gene. This protein consists of multiple repeats homologous to the cold shock domain (CSD), a motif common to some bacterial and eukaryotic nucleic acids-binding proteins. The minimal region on unr required for the interaction with ALL-1 included two CSD and two intervening polypeptides. The interaction was confirmed by in vitro binding studies, and by coimmunoprecipitation from COS cells overexpressing the relevant segments of the two proteins. These results suggest that unr is involved in an interaction of ALL-1 with DNA or RNA.
Animals↗
Minimal region of loss at 13q14 in B-cell chronic lymphocytic leukemia.
Allelic loss at nonrandom chromosomal sites is thought to mark the position of tumor suppressor genes involved in the pathogenesis and progression of human malignancies. Solid tumors in particular have been found to harbor multiple genetic changes resulting in loss of function mutations. Tumor suppressor genes have also been found to be involved in the progression of lymphoid tumors. Previous reports have suggested the involvement of a tumor suppressor gene located on the long arm of chromosome 13, between the retinoblastoma (RB) and D13S25 loci, in the pathogenesis and or progression of more than 40% of B-cell chronic lymphocytic leukemia (B-CLL), a common lymphoid malignancy whose molecular etiology remains largely unknown. In the present study, we report the construction and characterization of a YAC contig spanning a region of approximately 3 cM between the RB gene and the D13S31 locus. We also screened 60 paired normal/tumor B-CLL samples for allelic loss on chromosome 13 with nine microsatellite markers located between RB and D13S25. This analysis has allowed us to narrow the smallest region of loss to a segment of 550 kb located between the 206XF12 and D13S25 markers.
Alleles↗