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Biomedical subjects

M Grieco

Publications and source records attributed to M Grieco.

At least 37 records · Page 2Linked to original sources
PubMed1993

The Adenovirus E1A gene blocks the differentiation of a thyroid epithelial cell line, however the neoplastic phenotype is achieved only after cooperation with other oncogenes.

The PC Cl 3 cell line is a well characterized epithelial thyroid cell line of Fischer rat origin. This cell line has the peculiarity of retaining in vitro the typical markers of thyroid differentiation (i.e. thyroglobulin synthesis and secretion, iodide uptake and dependence on TSH for growth). The PC Cl 3 cells have been transfected with the E1A gene of Adenovirus 5. The E1A transfected cells, PC E1A, partially lost the dependency on TSH for growth and completely lost the ability to trap iodide and synthesize thyroglobulin; however they did not acquire the typical markers of the neoplastic phenotype. A highly malignant phenotype was achieved after infection of the PC E1A cells with retroviruses carrying the v-raf, v-abl and polyoma virus middle T oncogenes. In contrast, the PC E1A cells transfected with the E1B gene of Adenovirus were not tumorigenic at all, and those infected with retroviruses carrying oncogenes of the ras family displayed a very weak tumorigenic phenotype.

Adenovirus E1A Proteins↗
PubMed1993

The TRK and RET tyrosine kinase oncogenes cooperate with ras in the neoplastic transformation of a rat thyroid epithelial cell line.

We have recently reported that about 50% of papillary thyroid carcinomas harbor an activated TRK or RET oncogene. Two retroviral vectors containing the activated TRK or RET/PTC oncogene have been used to infect a differentiated rat thyroid epithelial cell line, namely the PC Clone 3 cell line. Upon infection with the TRK virus, the PC Clone 3 cells lost only the ability to trap iodide and to express the thyroperoxidase gene. Conversely, when infected with the PTC virus, the PC Clone 3 cells completely lost all of their differentiated functions. However, both the PC-TRK and PC-PTC cell lines were unable to grow in soft agar, and they were not tumorigenic when injected into nude mice. A completely undifferentiated and malignant phenotype was obtained by the cooperation between the TRK or RET and the viral Ha-ras or Ki-ras oncogenes.

Animals↗
PubMed1992

Characterization of an inversion on the long arm of chromosome 10 juxtaposing D10S170 and RET and creating the oncogenic sequence RET/PTC.

RET/PTC is a transforming sequence created by the fusion of the tyrosine kinase domain of the RET protooncogene with the 5' end of the locus D10S170 designated by probe H4 and is frequently found activated in human papillary thyroid carcinomas. RET and D10S170 have been mapped to contiguous regions of the long arm of chromosome 10: q11.2 and q21, respectively. To identify the mechanism leading to the generation of the oncogenic sequence RET/PTC, a combined cytogenetic and molecular analysis of several cases of papillary thyroid carcinomas was done. In four cases the results indicated that these tumors had RET/PTC activation and a paracentric inversion of the long arm of chromosome 10, inv(10)(q11.2q21), with breakpoints coincident with the regions where RET and D10S170 are located. Therefore, a chromosome 10q inversion provides the structural basis for the D10S170-RET fusion that forms the hybrid transforming sequence RET/PTC.

Blotting, Southern↗
PubMed1992

Detection of RET oncogene activation in human papillary thyroid carcinomas by in situ hybridisation.

We have recently reported the activation of a new oncogene in human papillary thyroid carcinomas. This oncogene, named PTC, is a novel rearranged version of the ret proto-oncogene. In fact PTC is the product of the fusion of the tyrosine kinase domain of the ret proto-oncogene with the 5'-terminal region of another gene that we have named H4. The ret proto-oncogene shows a pattern of expression restricted to neuroendocrine tissue. Its fusion with H4 allows the expression of the activated form in thyroid papillary carcinomas. Therefore the detection of ret transcripts is a tool to investigate ret activation in thyroid neoplasms. Here we show the detection by in situ hybridisation, of activated ret transcripts in human thyroid papillary neoplasms that were positive for PTC activation by Southern blot analysis. We did not find any ret transcripts in papillary carcinomas negative for PTC activation, nor in normal thyroid and in non-papillary thyroid neoplasias.

3T3 Cells↗
PubMed1992

Ret oncogene activation in human thyroid neoplasms is restricted to the papillary cancer subtype.

We have recently reported the activation of a new oncogene in human papillary thyroid carcinomas. This oncogene, papillary thyroid carcinoma (PTC), is a novel rearranged version of the ret tyrosine-kinase protooncogene. Thyroid neoplasms include a broad spectrum of malignant tumors, ranging from well-differentiated tumors to undifferentiated anaplastic carcinomas. To determine the frequency of ret oncogene activation, we analyzed 286 cases of human thyroid tumors of diverse histologic types. We found the presence of an activated form of the ret oncogene in 33 (19%) of 177 papillary carcinomas. By contrast, none of the other 109 thyroid tumors, which included 37 follicular, 15 anaplastic, and 18 medullary carcinomas, and 34 benign lesions, showed ret activation.

Base Sequence↗
PubMed1992

Identification of the product of two oncogenic rearranged forms of the RET proto-oncogene in papillary thyroid carcinomas.

In papillary thyroid carcinomas, we have identified two tumor-specific rearrangements of the RET proto-oncogene leading to the formation of different transforming fusion products sharing the tyrosine kinase (tk) domain of the proto-oncogene and designated ptc-1 and ptc-2. We have analysed ptc-1 and ptc-2 products by immunoprecipitation with specific anti-RET antibodies followed by immunoblotting with the same reagent or with antibodies specific for phosphotyrosine (P-tyr) residues. The anti-RET antibodies were reactive with 64-kDa (p64ptc-1) and 81-kDa (p81ptc-2) proteins from lysates of ptc-1 and ptc-2 transformed cells, respectively, and identified two proteins of 140 kDa and 160 kDa from extracts of SK-N-SH, a neuroblastoma cell line previously shown to express two differently glycosylated forms of the normal RET product. The anti P-tyr antibodies, while detecting the same p64ptc-1 and p81ptc-2 proteins from ptc-1 and ptc-2 extracts, did not show any specific band in the neuroblastoma lysates. An additional set of experiments led us to conclude that, whereas the normal product of the RET proto-oncogene is a membrane-associated receptor-like molecule not intrinsically phosphorylated on tyrosine, both oncogenic forms of RET, ptc-1 and ptc-2, are constitutively phosphorylated on tyrosine, display an 'in vitro' autophosphorylation activity, are translocated from the membrane to the cytoplasm and are apparently unaffected by protein kinase C modulation.

3T3 Cells↗
PubMed1991

Refined localization to contiguous regions on chromosome 10q of the two genes (H4 and RET) that form the oncogenic sequence PTC.

In this report we confirm the localization of the human RET proto-oncogene to chromosome 10q11.2, both by Southern blot analysis of a panel of human-rodent somatic cell hybrids and by in situ hybridization on human metaphase chromosomes. Previously, we had assigned to the same chromosome region the gene termed H4. In about 25% of papillary thyroid carcinomas, this gene was shown to rearrange with RET to give rise to the transforming sequence PTC. The analysis of different cell hybrids containing subfragments of chromosome 10, in conjunction with pulse field gel electrophoresis, established that H4 is mapped distally to RET at a distance not less than 280 kb. These findings suggest that intrachromosomal rearrangements are responsible for PTC activation in papillary thyroid carcinomas.

Carcinoma, Papillary↗
PubMed1990

Thyrotropin receptor gene expression in oncogene-transfected rat thyroid cells: correlation between transformation, loss of thyrotropin-dependent growth, and loss of thyrotropin receptor gene expression.

Rat FRTL-5 and PC-Cl-3 thyroid cells are continuously cultured, clonal lines which require thyrotropin to grow and function. Both can be efficiently transformed when infected with RNA or DNA viruses carrying oncogenes or when directly transfected with activated oncogenes. Transformation, assayed by the appearance of cell growth in agar and by tumorigenicity in syngeneic rats or nude mice, is associated with the loss of thyrotropin-dependent cell division and thyrotropin-regulated functions such as thyroglobulin synthesis. In 16 clones of FRTL-5 or PC-Cl-3 cells transformed with different oncogenes, we show that loss of thyrotropin-dependent growth and function correlates with the loss of thyrotropin receptor gene expression, measured with a rat thyrotropin receptor cDNA probe.

Animals↗
PubMed1990

PTC is a novel rearranged form of the ret proto-oncogene and is frequently detected in vivo in human thyroid papillary carcinomas.

We recently detected a novel activated oncogene by transfection analysis on NIH 3T3 cells in five out of 20 primary human thyroid papillary carcinomas and in the available lymph node metastases. We designated this transforming gene PTC (for papillary thyroid carcinoma). Here we describe the molecular cloning and sequencing of the gene. The new oncogene resulted from the rearrangement of an unknown amino-terminal sequence to the tyrosine kinase domain of the ret proto-oncogene. This gene rearrangement was detected in all of the transfectants and in all of the original tumor DNAs, but not in normal DNA of the same patients, thus indicating that this genetic lesion occurred in vivo and is specific to somatic tumors. Moreover, the transcript coded for by the fused gene was detected in an additional PTC-positive human papillary carcinoma for which mRNA was available.

Amino Acid Sequence↗
PubMed1990

The ret proto-oncogene is consistently expressed in human pheochromocytomas and thyroid medullary carcinomas.

We have recently reported the identification of a new oncogene, named PTC, frequently activated in human thyroid papillary carcinomas. This gene is a novel rearranged form of the ret proto-oncogene and we have shown that this rearrangement occurred in vivo as a tumor-specific somatic event. In an effort to further examine the role of this oncogene in human malignancies, we have investigated the expression of the ret oncogene in a number of human tumors. We consistently detected expression of normal-sized transcripts of the ret proto-oncogene in human pheochromocytomas and in human medullary thyroid carcinomas (MTC), both of familial and sporadic type. Moreover, we showed that ret mRNA levels were increased following (Bu)2cAMP-induced differentiation of a human MTC cell line (TT). Since the ret gene has been mapped on chromosome 10, close to the gene which predisposes patients to the MEN2A syndrome, we suggest that this region of chromosome 10 might be involved in the proliferative and differentiative patterns of these neuroectodermal tissues.

Adrenal Gland Neoplasms↗
PubMed1990

Comparison of safety and efficacy of inhaled pirbuterol with metaproterenol.

This multicenter study was performed to compare the safety and efficacy of a new beta-2 selective beta agonist, pirbuterol, with metaproterenol. The study followed a double-blind parallel design evaluating 133 asthmatic patients for 12 weeks. There were essentially no clinical differences between groups and no differences in onset of action, peak effect, side effects, or development of tolerance between these two agents. Our conclusion is that pirbuterol is at least as effective and safe under conditions of chronic administration to asthmatics as metaproterenol and therefore can be considered a suitable alternative for therapy.

Administration, Inhalation↗
PubMed1989

The Kirsten murine sarcoma virus induces rat thyroid carcinomas in vivo.

The injection of a retrovirus carrying the v-ras-Ki oncogene into the thyroid gland of adult Fischer rats induces thyroid carcinomas when associated with a treatment of the animals with a goitrogenic agent. More than one hundred adult Fischer rats have been treated with the goitrogen agent propylthiouracil in order to induce thyroid hyperplasia. Twenty days after treatment, rat thyroid glands, surgically prepared, were injected with the Kirsten murine sarcoma virus (KiMSV). Within three months more than 90% of the animals developed thyroid tumors. Histologically the tumors had the appearance of well differentiated carcinomas. Thirty animals had lung metastases in addition to the thyroid carcinoma. The presence of KiMSV specific transcripts and the specific transforming protein (p21) in thyroid carcinomas and in the metastases was detected by Northern blot analysis and immunoprecipitation, respectively. Only three rats, among thirty that had not received the goitrogen treatment, but only the injection with KiMSV, developed thyroid carcinomas of very small size and with a very long latency period (almost one year). The results described represent the first instance of thyroid carcinoma induction by retroviruses. This system may be regarded as a useful model to investigate the process of thyroid carcinogenesis in vivo. These results suggest that this model may also be useful for investigating the interaction between hormones and cells harboring the activated oncogene in the development of thyroid carcinoma since activated ras oncogenes have been implicated in human thyroid carcinoma.

Animals↗
PubMed1989

The oncogene associated with human papillary thyroid carcinoma (PTC) is assigned to chromosome 10 q11-q12 in the same region as multiple endocrine neoplasia type 2A (MEN2A).

In this report we assigned to chromosome 10q the human oncogene PTC frequently associated with the papillary type of thyroid carcinoma. Using an informative panel of human-mouse somatic cell hybrids and 'in situ' hybridization to human metaphase chromosomes, we localized the PTC gene at bands q11-q12 of chromosome 10. These bands belong to one of the two regions on chromosome 10 linked to the cancer syndrome multiple endocrine neoplasia type 2A (MEN2A). Therefore, it is suggested that genes clustered in certain regions of chromosome 10 could be involved in the developmental regulation of the thyroid gland.

Carcinoma, Papillary↗
PubMed1989

High frequency of activation of tyrosine kinase oncogenes in human papillary thyroid carcinoma.

We had previously detected a transforming oncogene, designated PTC, in 25% of 20 papillary thyroid carcinomas. In order to characterize further the transforming activity of this tumour histotype, a new panel of tumour specimens from 16 patients was analysed by using a modified calcium phosphate-DNA coprecipitation transfection protocol. Tumour DNA from 10 patients (62%) displayed a transforming activity due to activation of three different oncogenes identified in four cases as PTC, in four cases as TRK, and in two cases as N-RAS. The same structural alterations of PTC and TRK (gene rearrangements) as well as of N-RAS (point mutation) detected in the NIH3T3 transformants, were also found in the original tumour DNAs, thus indicating that their activation was not due to transfection procedures. Since both PTC, a novel rearranged form of RET, and TRK display a tyrosine protein kinase activity, it is proposed that the activation of this class of oncogenes is specifically involved in the pathogenesis of papillary thyroid cancer.

Animals↗
PubMed1988

Protein kinase C activities are increased in rat thyroid epithelial cells expressing v-ras genes.

Both cytoplasmic and membrane-bound protein kinase C activities are increased in: Harvey-Sarcoma Virus, infected thyroid epithelial cells. The cytoplasmic kinase C increase is found in the chromatographic fraction eluted at lower salt concentration (100 mM NaCl-S100), while the more acidic protein fraction eluted at higher salt concentration (35 mM NaCl-S350) is virtually absent. Although the cytoplasmic S100 fraction from the control and ras-virus infected cells display a comparable PBt2 binding activity, they are different in the Ca+2-dependence and the TPA down regulation. In addition, the membranes from the control and ras-virus infected cells are different phosphate acceptors in place of the H1 histones.

Animals↗
PubMed1988

The relationship of modulation of major histocompatibility complex class I antigens to retrovirus transformation in rat cell lines.

The expression of major histocompatibility complex (MHC) Class I antigens has been studied, by means of monoclonal antibodies directed against nonpolymorphic determinants of MHC Class I molecules, in two epithelial differentiated cell lines (FRTL-5 clone 2 and PC clone 3) and in one fibroblast cell line (FRT Fibro) of Fischer rat thyroid origin, before and after infection with various acute retroviruses carrying the v-ras-Ha, v-mos, v-src, polyoma middle T, and c-myc oncogenes. The results obtained indicate that a single virus does not produce identical changes in MHC Class I molecule expression in all tested lines, but a general increase occurs in lines derived from FRTL-5 clone 2 and a decrease occurs in lines derived from PC clone 3 and from FRT Fibro. Thus the modulation of expression seems to proceed always in the same direction in each cell line regardless of the infecting retrovirus and appears to involve posttranscriptional mechanisms, since no modification of expression of mRNA levels has been observed between normal and transformed cells. Only one line of PC clone 3 origin, transformed by the cooperation of two oncogenes (human c-myc and middle T), almost completely lost MHC Class I antigens on the cell surface and presented a significantly reduced synthesis of Class I mRNA.

Animals↗