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Biomedical subjects

A Fusco

Publications and source records attributed to A Fusco.

At least 73 records · Page 4Linked to original sources
PubMed2000

Pancreatic duct cell carcinomas express high levels of high mobility group I(Y) proteins.

The high mobility group I (HMGI) family of proteins in mammals belongs to a group of nonhistone nuclear proteins known as architectural transcriptional factors. They function in vivo as both structural components of chromatin and auxiliary gene transcription factors. In an earlier study (N. Abe et al, Cancer Res., 59: 1169-1174, 1999), we demonstrated that the expression level of the HMGI(Y) gene/proteins was significantly increased in colorectal adenocarcinoma and colorectal adenoma with severe cellular atypia. In the current study, we analyzed HMGI(Y) expression in several human pancreatic lesions to investigate (a) whether HMGI(Y) overexpression is also observed in pancreatic carcinoma, and (b) the role of HMGI(Y) in the diagnosis of pancreatic neoplasms. To this end, HMGI(Y) expression was determined at the protein level by immunohistochemistry using a HMGI(Y)-specific antibody in 6 surgically resected specimens of nonneoplastic tissue (4 specimens of normal pancreatic tissue and 2 specimens of chronic pancreatitis tissue), 8 pancreatic cystic neoplasms (5 intraductal papillary mucinous adenomas, 1 serous cystadenoma, and 2 solid pseudopapillary tumors), and 15 duct cell carcinomas of the pancreas. Immunohistochemical analysis revealed intense nuclear staining in the pancreatic carcinoma cells, whereas only very faint nuclear staining was seen in the nonneoplastic cells. There was a strong correlation between HMGI(Y) protein overexpression and a diagnosis of carcinoma (P = 0.000018). Thus, an increased expression level of the HMGI(Y) proteins was clearly associated with the malignant phenotype in pancreatic tissue. In addition, a low level of protein expression was also apparent in two of the cystic neoplasms that exhibited cellular atypia, but not in those that did not exhibit cellular atypia. Based on these findings, we propose that the HMGI(Y) proteins could be closely associated with tumorigenesis in the pancreas and that HMGI(Y) could serve as a potential diagnostic molecular marker for distinguishing pancreatic malignancies unambiguously from normal tissue or benign lesions.

Carcinoma↗
PubMed2000

Adenovirus-mediated suppression of HMGI(Y) protein synthesis as potential therapy of human malignant neoplasias.

High mobility group I (HMGI) proteins are overexpressed in several human malignant tumors. We previously demonstrated that inhibition of HMGI synthesis prevents thyroid cell transformation. Here, we report that an adenovirus carrying the HMGI(Y) gene in an antisense orientation (Ad-Yas) induced programmed cell death of two human thyroid anaplastic carcinoma cell lines (ARO and FB-1), but not normal thyroid cells. The Ad-Yas virus led to death of lung, colon, and breast carcinoma cells. A control adenovirus carrying the lacZ gene did not inhibit the growth of either normal or neoplastic cells. Ad-Yas treatment of tumors induced in athymic mice by ARO cells caused a drastic reduction in tumor size. Therefore, suppression of HMGI(Y) protein synthesis by an HMGI(Y) antisense adenoviral vector may be a useful treatment strategy in a variety of human malignant neoplasias, in which HMGI(Y) gene overexpression is a general event.

Adenoviridae↗
PubMed2000

A novel member of the BTB/POZ family, PATZ, associates with the RNF4 RING finger protein and acts as a transcriptional repressor.

We have identified a novel human gene encoding a 59-kDa POZ-AT hook-zinc finger protein (PATZ) that interacts with RNF4, a mediator of androgen receptor activity, and acts as a transcriptional repressor. PATZ cDNA was isolated through a two-hybrid interaction screening using the RING finger protein RNF4 as a bait. In vitro and in vivo interaction between RNF4 and PATZ was demonstrated by protein-protein affinity chromatography and coimmunoprecipitation experiments. Such interaction occurred through a small region of PATZ containing an AT-hook DNA binding domain. Immunofluorescence staining and confocal microscopy showed that PATZ localizes in distinct punctate nuclear regions and colocalizes with RNF4. Functional analysis was performed by cotransfection assays: PATZ acted as a transcriptional repressor, whereas its partner RNF4 behaved as a transcriptional activator. When both proteins were overexpressed a strong repression of the basal transcription was observed, indicating that the association of PATZ with RNF4 switches activation to repression. In addition, RNF4 was also found to associate with HMGI(Y), a chromatin-modeling factor containing AT-hook domains.

Amino Acid Sequence↗
PubMed2000

A 12q13 translocation involving the HMGI-C gene in richter transformation of a chronic lymphocytic leukemia.

We report a case of Richter transformation of a chronic lymphocytic leukemia with a 12q13 translocation involving the HMGI-C gene. Fluorescence in situ hybridization analysis with the use of two different cosmid pools spanning the entire HMGI-C region showed that the breakpoint on chromosome 12 was located in the HMGI-C gene, presumably within intron 3. In fact, the 3' region of HMGI-C had been translocated to a derivative chromosome 6. This translocation was not visible at the cytogenetic level. Immunohistochemical analysis performed on the bone marrow smear demonstrated the expression of the HMGI-C protein specifically in the blasts, suggesting that the aberrant expression of the HMGI-C gene might have an important role in the process of leukemogenesis.

Chromosomes, Human, Pair 12↗
PubMed2000

Gene rearrangement and Chernobyl related thyroid cancers.

The increase in thyroid carcinoma post-Chernobyl has been largely confined to a specific subtype of papillary carcinoma (solid/follicular). This subtype is observed predominantly in children under 10 in unirradiated populations, but maintains a high frequency in those aged 10-15 from those areas exposed to fallout from the Chernobyl accident. The aim of this study was to link morphology with molecular biology. We examined 106 papillary carcinomas from children under the age of 15 at operation. All were examined for rearrangements of the RET oncogene by reverse transcription polymerase chain reaction (RT-PCR); a subset of these cases were also examined for mutations of the three ras oncogenes, exon 10 of the thyroid stimulating hormone receptor, associated more usually with a follicular rather than papillary morphology, and exons 5, 6, 7 and 8 of the p53 gene, commonly involved in undifferentiated thyroid carcinoma. Rearrangements of the REToncogene were found in 44% of papillary carcinomas in which we studied fresh material; none of the tumours examined showed mutation in any of the other genes. The two rearrangements resulting from inversion of part of chromosome 10 (PTC1 and PTC3) accounted for the majority of RET rearrangements identified, with PTC1 being associated with papillary carcinomas of the classic and diffuse sclerosing variants and PTC3 with the solid/follicular variant.

Adolescent↗
PubMed2000

Effect of subclinical hypothyroidism on body fluid compartments.

OBJECTIVE: The present study was aimed to assess the effects of subclinical hypothyroidism on body composition (BC). SUBJECTS: Thirty-one women (age: 37 +/- 9.9 years) with a wide range of body mass index (BMI) were studied. Subclinical hypothyroidism was defined by a basal TSH > or = 4 mU/L and/or TRH stimulated peak > or = 30 mU/L. MEASUREMENTS: For each subject, weight, height, BMI, multifrequency bioelectrical impedance spectroscopy (BIS) and D2O and NaBr dilution tests were performed to assessed total body water (TBW) and extracellular water (ECW). Thyroid function (basal and TRH stimulated TSH, free T3, and free T4) were determined from fasting blood samples for all subjects. Total body dual energy X-ray absorptiometry (DXA) were used to measure fat mass (FM) and lean mass (Lean). RESULTS: The results of BIS were compared with the TBW and ECW estimated by the dilution techniques on the same individuals. The correlation was R2 = 0.65 for impedance at 5 kHz and ECW by NaBr and R2 = 0.72 for impedance at 100 kHz and TBW by D2O. Intracellular water (ICW) was calculated as differences between TBW and ECW measured by dilution methods. Percent of ECW and ICW were related to BMI (ANOVA, p < 0.001). No difference in TBW, body water distribution and body composition related to thyroid function was demonstrated. CONCLUSIONS: In our patients affected with subclinical hypothyroidism, with or without obesity, only obesity appeared related to TBW, ECW and ICW; the subclinical hypothyroidism, on the contrary, had no effect on compartments of body fluids. Bioimpedance is a valid tool to assess body fluid distribution in subclinical hypothyroidism.

Absorptiometry, Photon↗
PubMed2000

RET/PTC activation in hyalinizing trabecular tumors of the thyroid.

Hyalinizing trabecular tumor (HTT) of the thyroid is a neoplasm of follicular derivation with a histogenesis that is still the subject of debate. Morphologic affinities between HTT and papillary carcinoma, including nuclear pseudoinclusions and grooves, suggest that these tumors may be of similar origin. The authors investigated the relationship between these two types of tumors by assessing HTT for the presence of rearrangements of the proto-oncogene rearranged during transfection (RET) that, in thyroid tumors, are specific for papillary carcinoma. A series of 14 HTTs, including two cases associated with classic papillary carcinoma, was studied by means of immunohistochemistry and reverse transcription-polymerase chain reaction. Seven follicular adenomas with focal hyalinized trabecular areas served as control cases. Three of the 14 HTT cases under consideration displayed rearrangements of RET generating the RET/papillary thyroid carcinoma type 1 (PTC1) oncogene. In another case, RET expression was detected focally by immunohistochemistry alone. Finally, in one mixed HTT-papillary carcinoma sample, RET/PTC1 expression was detected, but only in the papillary component. None of the control follicular adenomas contained rearrangements of RET/PTC. These findings demonstrate that a comparable percentage (28.6%) of HTTs and papillary carcinomas exhibit the same RET proto-oncogene alterations. Thus, HTT may represent the "hyalinizing trabecular" variant of papillary carcinoma rather than a separate entity.

Adenoma↗
PubMed2000

Rat protein tyrosine phosphatase eta suppresses the neoplastic phenotype of retrovirally transformed thyroid cells through the stabilization of p27(Kip1).

The r-PTPeta gene encodes a rat receptor-type protein tyrosine phosphatase whose expression is negatively regulated by neoplastic cell transformation. Here we first demonstrate a dramatic reduction in DEP-1/HPTPeta (the human homolog of r-PTPeta) expression in a panel of human thyroid carcinomas. Subsequently, we show that the reexpression of the r-PTPeta gene in highly malignant rat thyroid cells transformed by retroviruses carrying the v-mos and v-ras-Ki oncogenes suppresses their malignant phenotype. Cell cycle analysis demonstrated that r-PTPeta caused G(1) growth arrest and increased the cyclin-dependent kinase inhibitor p27(Kip1) protein level by reducing the proteasome-dependent degradation rate. We propose that the r-PTPeta tumor suppressor activity is mediated by p27(Kip1) protein stabilization, because suppression of p27(Kip1) protein synthesis using p27-specific antisense oligonucleotides blocked the growth-inhibitory effect induced by r-PTPeta. Furthermore, we provide evidence that in v-mos- or v-ras-Ki-transformed thyroid cells, the p27(Kip1) protein level was regulated by the mitogen-activated protein (MAP) kinase pathway and that r-PTPeta regulated p27(Kip1) stability by preventing v-mos- or v-ras-Ki-induced MAP kinase activation.

Animals↗
PubMed2000

Tyrosines 1015 and 1062 are in vivo autophosphorylation sites in ret and ret-derived oncoproteins.

Point mutations of the RET receptor tyrosine kinase are responsible for the inheritance of multiple endocrine neoplasia (MEN) type 2 syndromes and are also present in a fraction of sporadic medullary thyroid carcinomas. Somatic rearrangements of the RET gene generating the chimeric RET/papillary thyroid carcinoma (PTC) oncogenes are the predominant molecular lesions associated with papillary carcinoma, the most frequent thyroid malignancy in humans. Oncogenic mutations cause constitutive activation of the kinase function of RET, which, in turn, results in the autophosphorylation of RET tyrosine residues critical for signaling. In vitro kinase assays previously revealed six putative RET autophosphorylation sites. The aim of the present study was to assess the phosphorylation of two such residues, tyrosines 1015 and 1062 (Y1015 and Y1062), in the in vivo signaling of RET and RET-derived oncogenes. Using phosphorylated RET-specific antibodies, we demonstrate that both Y1015 and Y1062 are rapidly phosphorylated upon ligand triggering of RET. Moreover, regardless of the nature of the underlying activating mutation, the concomitant phosphorylation of Y1015 and Y1062 is a common feature of the various oncogenic RET products (MEN2A, MEN2B, and PTC). This study shows that Ab-pY1062 is a useful tool with which to detect activated RET in human tumor cells and surgical samples. Finally, the microinjection of Ab-pY1062 antibodies into living cells demonstrates that Ret/PTC1 signaling is required to maintain the mitogenesis of a human carcinoma cell line expressing the Ret/PTC1 oncoprotein.

Amino Acid Sequence↗
PubMed2000

Association between the expression of E1A oncogene and increased sensitivity to growth inhibition induced by sustained levels of cAMP in rat thyroid cells.

OBJECTIVE: The aim of this study was to investigate: (i) whether a persistent increase of cAMP interferes with the proliferation of transformed thyroid cells, and (ii) whether the degree of malignancy is correlated with the sensitivity to a transient and/or sustained increase in intracellular cAMP levels. DESIGN AND METHODS: To address these questions we used thyroid cell lines transformed with E1A oncogene from adenoviruses 5 (PC E1A cell line) or 2 (PC HE4 cell line), or infected with the polyoma murine leukemia virus (PC PyMLV cell line) carrying the middle T gene of the polyoma virus, or, finally, expressing both E1A and PyMLV. These cell lines present various degrees of malignancy: PC EIA and PC HE4 cells are not tumorigenic; PC PyMLV cells induce non-invasive tumors after a long latency period; and PC EIA+PyMLV cells are highly tumorigenic. RESULTS AND CONCLUSIONS: Thyroid cell proliferation required the transient increase of intracellular cAMP levels, while persistent elevation of cAMP blocked the proliferation of normal thyroid PC Cl 3 cells and of PC Cl 3 cells transformed by a variety of different oncogenes. In addition, sustained levels of cAMP induced apoptosis in cells carrying the adenovirus EIA oncogene, but not in cells transformed with other oncogenes or in the wild-type PC Cl 3 cells. Furthermore, middle T gene of the polyoma virus seemed to afford protection only from apoptosis induced by cAMP when middle T is present in thyroid cells along with the E1A gene.

Adenovirus E1A Proteins↗
PubMed2000

The highly malignant phenotype of anaplastic thyroid carcinoma cell lines is recessive.

OBJECTIVE: The aim of our studies was to determine whether the phenotype of the anaplastic thyroid carcinomas is dominant or recessive. In fact, it is hypothesized, on the basis of epidemiological and pathological data, that undifferentiated thyroid carcinomas are derived from differentiated tumours through a mechanism of tumour progression. DESIGN: Cell hybrids have been generated by cell fusion of anaplastic thyroid carcinoma cell lines, which show a highly malignant phenotype, to cell lines deriving from differentiated thyroid carcinoma, which show a non-tumorigenic or a poorly tumorigenic phenotype. All of the parental cell lines showed impaired p53 gene function. RESULTS: The cell hybrids contained alleles from the parental cell lines. All of the cell hybrids showed a lower growth rate compared with the parental undifferentiated carcinoma cell lines and were unable to grow in soft agar and to induce tumours after injection into athymic mice. CONCLUSION: Taken together, these findings suggest that the highly malignant phenotype of the anaplastic thyroid carcinoma is achieved by the impairment of gene functions that negatively regulate cell growth, rather than by the activation of dominant oncogenes.

Animals↗
PubMed2000

Identification of a novel subtype of H4-RET rearrangement in a thyroid papillary carcinoma and lymph node metastasis.

RET/PTC chimeric oncogenes are generated by the fusion of heterologous genes to the RET tyrosine kinase encoding domain. These rearrangements are typical of papillary thyroid carcinomas. RET/PTC1 is one of the most frequently found RET/PTC version and, in all the cases so far reported, it is invariably generated by the fusion of the first encoding exon of the H4 gene to the RET kinase encoding domain. This results in the generation of an oncogenic protein containing the first 101 residues of the H4 protein at the N-terminus. We report the isolation of a novel subtype of H4-RET fusion, designated RET/PTC1L, from a human papillary carcinoma of the thyroid and lymph node metastasis. At variance with the classic one, this novel rearrangement generates a protein containing the N-terminal 150 residues of H4. RET/PTC1L is able to transform NIH 3T3 cells; its transforming ability, however, is 5-fold lower than that of the classic RET/PTC1 isoform. We propose that RET/PTC1L is a novel chimeric oncogene involved in thyroid tumorigenesis; its low transforming ability may be one of the reasons explaining the low frequency by which it is found in human thyroid carcinomas.

Carcinoma, Papillary↗
PubMed2000

Glial cell line-derived neutrotrophic factor and neurturin can act as paracrine growth factors stimulating DNA synthesis of Ret-expressing spermatogonia.

Glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) are related growth factors which exert trophic effects on several neuronal populations and developing kidney. GDNF-family ligands interact with membrane receptors designated GFRalphas which, in turn, mediate stimulation of the Ret receptor tyrosine kinase. Here we show that Ret, GFRalpha-1 (the GDNF receptor), and GFRalpha-2 (the NTN receptor) are expressed by testicular germ cells, while GDNF and NTN are expressed by Sertoli cells. Both GDNF and NTN stimulate DNA synthesis in spermatogonia. Furthermore, Ret, ligands and co-receptors are expressed in germ cell tumors. Thus, GDNF-family ligands may act as paracrine factors in spermatogenesis and this circuit may be active in germ cell tumors.

Animals↗
PubMed2000

Inhibitory action on GHRH-induced GH secretion of chronic tamoxifen treatment in breast cancer.

OBJECTIVE: Previous in vitro and in vivo studies on animal models have demonstrated that tamoxifen (TAM) inhibits GH secretion. Studies in humans are conflicting. The aim of this study was to evaluate the effect of chronic TAM treatment on GH secretory dynamics in the presence of negligible endogenous oestrogens, in postmenopausal women with breast cancer. PATIENTS: Ten female patients were studied over a 6-12-month period after surgical therapy, before medical therapy, and during chronic treatment with TAM (20 mg/day p.o.). MEASUREMENTS: In all subjects we performed a standard GHRH-test (50 mg i.v. as a bolus) and compared the single time points, the peak response and the areas under the curves (AUC), before and during treatment. In basal samples, we evaluated the circulating levels of IGF-1, IGF-BP3 and their ratio, SHBG, FSH, LH, Oestradiol (E2) and PRL. GH was assayed by Immunoradiometric assay (IRMA). Insulin-like growth factor type I (IGF-I), Insulin-like growth factor-binding protein-3 (IGF-BP3), FSH, LH and PRL were measured by Radioimmunoassay (RIA). SHBG was measured by a noncompetitive liquid phase immunoradiometric assay, while E2 was measured directly in plasma by a liquid phase technique. RESULTS: TAM chronic treatment significantly reduced GH response to GHRH at single time point evaluations, GH peak response (mean decrease: 59.8 +/- 7.3%) and GH-AUC (mean decrease 53.8 +/- 8.9%). TAM also significantly reduced plasma IGF-1 levels. No significant variations were found in IGF-BP3 levels or in the IGF-1/IGF-BP3 ratio. A significant inverse correlation between SHBG and IGF-1 circulating levels was noticed during TAM treatment. CONCLUSIONS: Our data show that long-term tamoxifen treatment blocks the response of GH to exogenous GHRH and reduces IGF-1 levels, possibly by a central mechanism other than the demonstrated peripheral action. The results of this study, keeping in mind the demonstrated mitogenic role of IGF-1 in cancer proliferation, can contribute to clarify the mechanism by which TAM exerts its antiproliferative effect.

Aged↗
PubMed2000

Retinoic acid induces neuronal differentiation of embryonal carcinoma cells by reducing proteasome-dependent proteolysis of the cyclin-dependent inhibitor p27.

Retinoic acid (RA) treatment of embryonal carcinoma cell line NTERA-2 clone D1 (NT2/D1) induces growth arrest and terminal differentiation along the neuronal pathway. In the present study, we provide a functional link between RA and p27 function in the control of neuronal differentiation in NT2/D1 cells. We report that RA enhances p27 expression, which results in increased association with cyclin E/cyclin-dependent kinase 2 complexes and suppression of their activity; however, antisense clones, which have greatly reduced RA-dependent p27 inducibility (NT2-p27AS), continue to synthesize DNA and are unable to differentiate properly in response to RA as determined by lack of neurite outgrowth and by the failure to modify surface antigens. As to the mechanism involved in RA-dependent p27 upregulation, our data support the concept that RA reduces p27 protein degradation through the ubiquitin/proteasome-dependent pathway. Taken together, these findings demonstrate that in embryonal carcinoma cells, p27 expression is required for growth arrest and proper neuronal differentiation.

Antineoplastic Agents↗
PubMed2000

FRA-1 expression in hyperplastic and neoplastic thyroid diseases.

fra-1 gene overexpression has been shown to represent a general event in thyroid cell transformation in vitro and in vivo. Moreover, inhibition of FRA-1 protein synthesis by stable transfection with a fra-1 antisense construct significantly reduces the malignant phenotype of the transformed thyroid cells, indicating a pivotal role of the fra-1 gene product in the process of cellular transformation. In the attempt to define the potential use of FRA-1 protein detection in the diagnosis of thyroid diseases, we analyzed Fra-1 expression by a combination of immunohistochemistry and reverse transcription-PCR (RT-PCR) assay in 174 samples of thyroid nodules (22 nodular hyperplasias, 102 follicular adenomas, 34 papillary carcinomas, 12 follicular carcinomas, and 4 anaplastic carcinomas) representative of the spectrum of thyroid tumor pathology. FRA-1 protein was abundant in all of the carcinoma samples (50/50, 100%), with an intense staining in the nucleus and the cytoplasm. Positive staining was also found in most of the adenomas (90 of 102; 88%), but in this case, the staining was restricted to the nucleus. Similar results were obtained from the analysis of thyroid goiters; however, the number of positive cases is lower than adenomas (8 of 22; 36%); moreover, the staining was not observed in all of the cells. Conversely, no FRA-1 protein was detectable in 12 normal thyroid tissue samples used as controls. RT-PCR analysis confirmed a higher fra-1 expression in papillary and follicular carcinomas compared with goiters and adenomas. fra-1 expression was also analyzed on 10 fine needle aspiration biopsy (FNAB) samples by RT-PCR. fra-1-specific mRNA was detected in seven of the eight FNABs corresponding to thyroid nodules that were eventually diagnosed as adenomas (three of four) and carcinomas (four of four) after surgery. Conversely, no fra-1 gene expression was observed in two FNABs derived from normal thyroid. Further studies are required before suggesting FRA-1 protein detection as a useful tool for the diagnosis of hyperplastic and neoplastic disorders of the thyroid gland.

Biopsy, Needle↗
PubMed1999

Sp1 and CTF/NF-1 transcription factors are involved in the basal expression of the Hmgi-c proximal promoter.

HMGI-C is a nuclear architectural factor which is expressed during embryogenesis but not in adult tissues while it becomes re-expressed following neoplastic transformation. In this paper we identify the promoter region of the mouse Hmgi-c gene and by stepwise deletion of the 5' sequences we map the promoter activity of the most abundant transcript to a very short fragment containing a long polypyrimidine/polypurine (ppyr/ppur) tract. We demonstrate that this tract is a multiple binding site for the transcription factors Sp1 and Sp3 and that in Drosophila SL2 cells, Sp1 activates the Hmgi-c promoter. In addition, another transcription factor, CTF/NF-1, binds the proximal promoter immediately downstream of this region and its mutation decreases transcription in NIH-3T3 cells. This study identifies factors responsible for the basal activity of Hmgi-c gene and provides a foundation for further analysis of the mechanism of its regulation.

Animals↗