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Biomedical subjects

C M Croce

Publications and source records attributed to C M Croce.

At least 163 records · Page 9Linked to original sources
PubMed1996

Molecular diagnosis of lymphoma.

The biologic and clinical heterogeneity of lymphomas represents the major obstacle to their diagnosis. Because histologic analysis, which is the initial diagnostic approach, has been demonstrated to be insufficient in the definition of certain types of lymphomas, molecular and immunologic techniques have been increasingly applied to obtain a precise diagnosis and to establish a correct treatment. Fluorescence in situ hybridization, in particular, is a powerful technique with many applications to the study of chromosomal rearrangements. In addition, because of their specificity and sensitivity, molecular techniques provide an important tool in assessing response to treatment, in detecting minimal residual disease, and in understanding the clinical and prognostic significance of the disease.

Blotting, Southern↗
PubMed1995

Domains with transcriptional regulatory activity within the ALL1 and AF4 proteins involved in acute leukemia.

The ALLI gene, located at chromosome band 11q23, is involved in acute leukemia through a series of chromosome translocations and fusion to a variety of genes, most frequently to A4 and AF9. The fused genes encode chimeric proteins proteins. Because the Drosophila homologue of ALL1, trithorax, is a positive regulator of homeotic genes and acts at the level of transcription, it is conceivable that alterations in ALL1 transcriptional activity may underlie its action in malignant transformation. To begin studying this, we examined the All1, AF4, AF9, and AF17 proteins for the presence of potential transcriptional regulatory domains. This was done by fusing regions of the proteins to the yeast GAL4 DNA binding domain and assaying their effect on transcription of a reporter gene. A domain of 55 residues positioned at amino acids 2829-2883 of ALL1 was identified as a very strong activator. Further analysis of this domain by in vitro mutagenesis pointed to a core of hydrophobic and acidic residues as critical for the activity. An ALL1 domain that repressed transcription of the reporter gene coincided with the sequence homologous to a segment of DNA methyltransferase. An AF4 polypeptide containing residues 480-560 showed strong activation potential. The C-terminal segment of AF9 spanning amino acids 478-568 transactivated transcription of the reporter gene in HeLa but not in NIH 3T3 cells. These results suggest that ALL1, AF4, and probably AF9 interact with the transcriptional machinery of the cell.

Acute Disease↗
PubMed1995

Mch3, a novel human apoptotic cysteine protease highly related to CPP32.

Recent evidence suggests that mammalian cysteine proteases related to Caenorhabditis elegans CED-3 are key components of mammalian programmed cell death or apoptosis. We have shown recently that the CPP32 and Mch2 alpha cysteine proteases cleave the apoptotic markers poly(ADP-ribose) polymerase (PARP) and lamins, respectively. Here we report the cloning of a new Ced-3/interleukin 1 beta-converting enzyme-related gene, designated Mch3, that encodes a protein with the highest degree of homology to CPP32 compared to other family members. An alternatively spliced isoform, named Mch3 beta, was also identified. Bacterially expressed recombinant Mch3 has intrinsic autocatalytic/autoactivation activity. The specific activity of Mch3 alpha toward the peptide substrate DEVD-7-amino-4-methylcoumarin and PARP resembles that of CPP32. Like interleukin 1 beta-converting enzyme and CPP32, the active Mch3 alpha is made of two subunits derived from a precursor (proMch3 alpha). It was of interest that recombinant CPP32-p17 subunit can form an active heteromeric enzyme complex with recombinant Mch3 alpha-p12 subunit and vice versa, as determined by the ability of the heteromeric complexes to induce apoptosis in Sf9 cells. These data suggest that proMch3 alpha and proCPP32 can interact to form an active Mch3 alpha/CPP32 heteromeric complex. We also provide evidence that CPP32 can efficiently cleave proMch3 alpha, but not the opposite, suggesting that Mch3 alpha activation in vivo may depend in part on CPP32 activity. The high degree of conservation in structure and specific activity and the coexistence of Mch3 alpha and CPP32 in the same cell suggests that the PARP cleavage activity observed during apoptosis cannot solely be attributed to CPP32 but could also be an activity of Mch3 alpha.

Alternative Splicing↗
PubMed1995

Genomic organization of the ATM locus involved in ataxia-telangiectasia.

The ATM gene, involved in the genetic disorder ataxia-telangiectasia (AT), has been identified recently. This gene is suspected to predispose to malignancy and is located in a chromosomal region that we have recently found deleted in 50 to 60% of breast and lung carcinomas. Because of its location and its function, the ATM gene is a strong candidate tumor suppressor or modifier gene of chromosome region 11q23. In this study, we define its genomic structure. The aim was to establish the basis for the development of mutation scanning methods based on DNA instead of RNA. We found that the gene spans a region of approximately 70-80 kb and is composed of 37 exons, ranging in size from 64 to 324 bp. Nucleotide sequences of all exon/intron boundaries were determined. With this information, it will be possible to develop simple genetic tests for the identification of homozygotes and heterozygotes, as well as determine whether the gene is involved in the pathogenesis of breast and other carcinomas.

Ataxia Telangiectasia↗
PubMed1995

Characterization of the receptor protein tyrosine phosphatase gene product PTP gamma: binding and activation by triphosphorylated nucleosides.

A full-length cDNA for a novel isoform of the human receptor tyrosine phosphatase gamma gene (PTPRG) was overexpressed in Sf9 insect cells, and the gene product, PTP gamma, was purified and characterized. The protein was expressed as a M(r) approximately 185,000 protein accompanied by a M(r) approximately 120,000 putative cleavage product on SDS-PAGE analysis. The protein undergoes N-linked glycosylation and constitutive phosphorylation of serine residues. When assayed for tyrosine-specific phosphatase activity, PTP gamma dephosphorylated myelin basic protein at a pH optimum of 7.5 and a Km of 12.6 microM; reduced carboxyamidomethylated and maleylated lysozyme (RCM-lysozyme) at a pH optimum of 6.0 and a Km of 12 microM; and p-nitrophenylphosphate with a pH optimum of 5.5 and a Km of 3.5 mM. Phosphatase activity was inhibited by ZnCl2 and sodium orthovanadate; Mg2+, Mn2+, and Ca2+ ions were ineffective. The partially purified form of the enzyme was allosterically activated by triphosphorylated nucleosides, with a preference for purines. This activation was prevented by Mg2+ addition and did not occur when a purified form of the enzyme was utilized, suggesting that its activation depends on specific activating factors or conformational constraints. Interestingly, PTP gamma protein was specifically bound by an ATP-agarose matrix through its intracellular domain, suggesting a link between binding of nucleotides and activation of the phosphatase.

Adenosine Triphosphate↗
PubMed1995

TCL1 oncogene activation in preleukemic T cells from a case of ataxia-telangiectasia.

The TCL1 oncogene on human chromosome 14q32.1 is involved in chromosome translocations [t(14;14)(q11;q32.1) and t(7;14)(q35;q32.1)] and inversions [inv14(q11;q32.1)] with TCR alpha/beta loci in T-cell leukemias, such as T-prolymphocytic (T-PLL). It is also involved in T-acute and -chronic leukemias arising in cases of ataxia-telangiectasia (AT), an immunodeficiency syndrome. Similar chromosomal rearrangements occur also in the clonally expanded T cells in AT patients before the appearance of the overt leukemia. We have analyzed the expression of TCL1 mRNA and protein in peripheral blood lymphocytes (PBLs) from four AT cases and from healthy controls. We found that the TCL1 gene was overexpressed in the PBLs of an AT patient with a large clonal T-cell population exhibiting the t(14;14) translocation but not in the lymphocytes of the other cases. Fluorescence in situ hybridization of the TCL1 genomic locus to lymphocyte metaphases from the AT patient with the T-cell clonal expansion showed that the breakpoint of the t(14;14) translocation lies within the TCL1 locus and is accompanied by an inverted duplication of the distal part of chromosome 14. These data indicate that TCL1 is activated in preleukemic clonal cells as a consequence of chromosome translocation involving sequences from the TCR locus at 14q11. Deregulation of TCL1 is the first event in the initiation of malignancy in these types of leukemias and represents a potential tool for clinical evaluation.

Adolescent↗
PubMed1995

Loss of heterozygosity at chromosome 11q in lung adenocarcinoma: identification of three independent regions.

We examined the pattern of allelic loss in 76 adenocarcinomas of the lung using 14 highly informative microsatellite markers on the long arm of chromosome 11. Loss of heterozygosity was found in 48 of 76 tumors (63%). Three distinct regions of deletion were identified. The first region, the most centromeric, lies between markers D11S940 and CD3D: the second, delimited by markers D11S924 and D11S925, is estimated to be 4 Mb in length, and has never been previously described; a third, more telomeric region, the length of which is also estimated to be in the range of 4 Mb, is bracketed by loci D11S1345 and D11S1328. These findings suggest the presence of at least three tumor suppressor genes on the long arm of chromosome 11, and confirm the relevance of 11q22-24, a region frequently deleted in carcinomas of the breast, ovary, uterine, cervix, colon, and malignant melanoma in the pathogenesis of solid tumors. The characterization of minimal regions of loss could provide the basis for the identification and cloning of the critical genes.

Adenocarcinoma↗
PubMed1995

Seven megabase yeast artificial chromosome contig at region 11p15: identification of a yeast artificial chromosome spanning the breakpoint of a chromosomal translocation found in a case of Beckwith-Wiedemann syndrome.

Genetic alterations of chromosome region 11p15 have been detected in neoplastic diseases as well as in cancer-predisposing syndromes. The cloning of the entire chromosomal region will be important for the identification and characterization of critical tumor suppressor genes. We have developed a yeast artificial chromosome contig that covers up to 7 Mb of this chromosome band. The most centromeric marker included in the contig is D11S932 and the most telomeric is D11S470. We have developed 18 new STS markers, which have been located in the contig in relation to 16 known markers. One of the yeast artificial chromosome clones was found to span the chromosome 11 breakpoint of the translocation t(11;18), associated with a case of Beckwith-Wiedemann syndrome. Cloning the regions in proximity to this translocation might reveal the presence of a gene altered in association with the development of Beckwith-Wiedemann syndrome.

Base Sequence↗
PubMed1995

Involvement of the ALL-1 gene in a solid tumor.

Translocations involving chromosome band 11q23, found in 5-10% of human acute leukemias, disrupt the ALL-1 gene. This gene is fused by reciprocal translocation with a variety of other genes in acute lymphoblastic and myelogenous leukemias, and it undergoes self-fusion in acute myeloid leukemias with normal karyotype or trisomy 11. Here we report an alteration of the ALL-1 gene in a gastric carcinoma cell line (Mgc80-3). Characterization of this rearrangement revealed a three-way complex translocation, involving chromosomes 1 and 11, resulting in a partial duplication of the ALL-1 gene. Sequencing of reverse transcription-PCR products and Northern blot analysis showed that only the partially duplicated ALL-1 gene was transcribed, producing an mRNA with exon 8 fused to exon 2. This report of ALL-1 gene rearrangement in a solid tumor suggests that ALL-1 plays a role in the pathogenesis of some solid malignancies. The absence of the normal transcript in this cell line, in association with the loss-of-heterozygosity studies on chromosome 11q23 seen in solid tumors, suggests that ALL-1 is involved in tumorigenesis by a loss-of-function mechanism.

Animals↗
PubMed1995

Inactivation of Bcl-2 by phosphorylation.

The antiapoptosis potential of Bcl-2 protein is well established, but the mechanism of Bcl-2 action is still poorly understood. Using the phosphatase inhibitor okadaic acid or the chemotherapeutic drug taxol, we found that Bcl-2 was phosphorylated in lymphoid cells. Phospho amino acid analysis revealed that Bcl-2 was phosphorylated on serine. Under similar conditions, okadaic acid or taxol treatment led to the induction of apoptosis in these cells. Thus, phosphorylation of Bcl-2 seems to inhibit its ability to interfere with apoptosis. In addition, phosphorylated Bcl-2 can no longer prevent lipid peroxidation as required to protect cells from apoptosis.

Apoptosis↗
PubMed1995

Expression of the prostate-specific antigen gene by a primary ovarian carcinoma.

We describe a patient with primary ovarian carcinoma that developed after liver transplantation whose tumor was highly positive for prostate-specific antigen (PSA). PSA in tumor tissue was characterized by two immunoassays, HPLC, immunohistochemistry, reverse transcription-PCR, Southern blotting, and DNA sequencing. PSA in the ovarian tumor was present as free, M(r) 33,000 protein (> 90%) and as PSA bound to alpha 1-antichymotrypsin (M(r) 100,000; < 10%). Immunohistochemistry localized PSA in the cytoplasm of epithelial cells of the tumor. Two separate reverse transcription-PCRs for PSA amplified the expected products which hybridized specifically to a PSA cDNA probe on Southern blots. Sequencing of the PCR products, representing the whole coding sequence of the PSA gene, revealed identity with the sequence of PSA cDNA from prostate tissue. These data suggest that the PSA produced by the ovarian tumor was identical in molecular weight and sequence to prostatic PSA. Based on data of tissue culture experiments with breast carcinoma cell lines, we speculate that the PSA gene in the tumor of this patient was up-regulated by the therapeutically administered glucocorticoids after liver transplantation.

Base Sequence↗
PubMed1995

ALL-1 gene rearrangements in acute myeloid leukemia: association with M4-M5 French-American-British classification subtypes and young age.

We have analyzed by Southern blotting the ALL-1 (MLL, HRX, Hrtx 1) gene configuration in a series of 126 patients with acute myeloid leukemia (AML) representative of all ages and French-American-British Classification groups and correlated this genetic feature with clinical and biological features at diagnosis. ALL-1 gene rearrangements were detected in 17 of the 74 cases with M4-M5 (myelomonocytic and monocytic) AML and in 2 of the 52 cases with other leukemic subtypes (P < 0.01). Within the series of 74 M4-M5 patients, ALL-1 rearrangements were significantly associated with French-American-British Classification M5 (P = 0.009), high WBC (P = 0.002), and young age. In particular, all 5 infant (< 1.5 years) AML cases, 6 of the 19 (31%) patients between 1.5 and 18 years of age, and 6 of the 50 (12%) patients > 18 years old showed an altered ALL-1 genomic configuration (P < 0.001). Immunophenotypic characterization revealed coexpression of lymphoid and myeloid markers in 6 of 17 ALL-1 rearranged M4-M5 cases. The IgH gene configuration was studied in 77 of 126 AMLs. Five patients (6%) showed IgH clonal rearrangements and all were in the ALL-1 rearranged group (P < 0.0001). Our findings indicate that ALL-1 rearrangement is the commonest genetic alteration presently detectable in M4-M5 AML, particularly in childhood where it is found in up to one-third of all cases. The association of IgH rearrangements with ALL-1 alterations in AML, coupled to the frequent detection in this subset of lymphoid associated markers, further supports the origin of these tumors from a common multipotent precursor with bipotential lymphoid and monocytic differentiation capability.

Adolescent↗
PubMed1995

Detection and cloning of a common region of loss of heterozygosity at chromosome 1p in breast cancer.

The short arm of chromosome 1 is frequently affected by rearrangements in a variety of human malignancies. Genetic alterations, predominantly deletions, which are indicative of the presence of a putative tumor suppressor gene at chromosome 1p, are observed in breast cancer. In order to define the altered locus, eleven highly polymorphic microsatellite markers on chromosome 1p were used to detect loss of heterozygosity. We analyzed 52 cases of breast cancer and found 4 common deleted regions at chromosome 1p. Twenty-two of 52 (42%) informative patients showed at least 1 affected locus. The region most frequently exhibiting loss of heterozygosity was 1p31 (11/39; 28%); the other three common deleted regions were 1p36 (10/44; 23%), 1p35-36 (5/40; 13%), and 1p13 (8/39; 21%). These data suggest that one or more putative tumor suppressor genes may reside on chromosome 1p. We have cloned the entire region of interest at 1p31 in yeast artificial chromosomes. This yeast artificial chromosome contig can be used for fine mapping of the region and cloning of the candidate tumor suppressor gene.

Base Sequence↗
PubMed1995

Detection of myc translocations in lymphoma cells by fluorescence in situ hybridization with yeast artificial chromosomes.

Translocations involving chromosome 8 at band q24 and one of the Ig loci on chromosomes 14q32, 22q11, and 2p11 are the hallmark of Burkitt's lymphoma (BL). It has been previously observed that the exact localization of the breakpoints at chromosome 8q24 can vary significantly from patient to patient, scattering over a distance of more than 300 kb upstream of c-myc and about 300 kb downstream of c-myc. To generate probes for fluorescence in situ hybridization (FISH) that detect most c-myc translocations, we screened a yeast artificial chromosome (YAC) library from normal human lymphocytes by colony hybridization, using three markers surrounding the c-myc gene as probes. We obtained 10 YAC clones ranging in size between 500 and 200 kb. Two nonchimeric clones were used for FISH on several BL cell lines and patient samples with different breakpoints at 8q24. Our results show that the YAC clones detected translocations scattered along approximately 200 kb in both metaphase chromosomes and interphase nuclei. The sensitivity, rapidity, and feasibility in nondividing cells render FISH an important diagnostic tool. Furthermore, the use of large DNA fragments such as YACs greatly simplifies the detection of translocations with widely scattered breakpoints such as these seen in BL.

Adult↗
PubMed1995

Oral contraceptive-induced expression of prostate-specific antigen in the female breast.

Prostate-specific antigen (PSA) is widely used as a tumor marker of prostatic adenocarcinoma. We recently found that 30% of breast tumors produce PSA and that PSA is a favorable prognostic marker in female breast cancer. We measured immunoreactive PSA in cytosolic extracts of normal breast tissue from eight women receiving no medication and one woman who was receiving no medication and one woman who was receiving the progestin-containing oral contraceptive Brevicon. None of the eight cytosolic extracts of normal breast tissue contained appreciable amounts of immunoreactive PSA. However, left and right breast tissues from the woman receiving Brevicon contained high levels of PSA. This immunoreactive species was shown to have a molecular weight identical to that of seminal PSA. Furthermore, reverse transcription of RNA and polymerase chain reaction amplification produced a 571-base pair cDNA that hybridized to a labeled cDNA PSA probe. Upon sequencing, the cDNA polymerase chain reaction product was found to have 100% homology with cDNA from prostatic tissue. PSA production by breast carcinoma cell lines was achieved after in vitro stimulation with norethindrone and ethinylestradiol. Our data suggest that PSA can no longer be regarded as a specific prostatic protein because it is produced by breast tumors with good prognosis and by normal breast tissue after steroid hormone stimulation.

Base Sequence↗
PubMed1995

Chromosomal mapping of members of the cdc2 family of protein kinases, cdk3, cdk6, PISSLRE, and PITALRE, and a cdk inhibitor, p27Kip1, to regions involved in human cancer.

Orderly progression through the cell cycle requires sequential activation and inactivation of cyclin-dependent kinases (cdks). This is achieved in part through the association of cdks with positive regulators called cyclins and inactivation of cyclin-cdk complexes by a rapidly growing number of cyclin-cdk inhibitors. Recently, the role of cell cycle control proteins both as primary effectors and as mediators of tumorigenesis has become a subject of increased interest. Here we report the chromosomal mapping of two cdks, cdk3 and cdk6, two putative cdks, PISSLRE and PITALRE, and one cyclin-dependent kinase inhibitor, p27, to chromosomal regions which may be altered in human tumors and examine their possible involvement in some of these malignancies. In particular, two of the kinases, cdk3 and PISSLRE and PITALRE, the cdc2-related kinases recently cloned by us, map to regions previously shown to exhibit loss of heterozygosity in breast and other tumors.

Base Sequence↗