Induction of cells with phenotypic features of neuronal cells by treatment with dibutyryl cyclic adenosine 3',5'-monophosphate in a human parotid gland adenocarcinoma cell line in culture.

A human parotid gland adenocarcinoma cell line, with an intercalated duct cell phenotype of the salivary gland and expression of vasoactive intestinal polypeptide and amylase, was cultivated in the presence of dibutyryl cyclic adenosine 3',5'-monophosphate (dB-cAMP). Morphological changes occurred; cells formed long cytoplasmic processes densely packed with ample microfibrils, as well as microtubules, and grew in a netlike appearance. In addition, it has been found by the immunofluorescence staining technique, immunoblotting, or immunoelectron microscopy that the cells treated with dB-cAMP express neurofilaments, neuron-specific enolase, synaptophysin, and HNK-1 antigen, as well as the alpha- and beta-chains of tubulin, whereas these antigens are not detected in untreated cells. The expression of vasoactive intestinal polypeptide detected diffusely in the cytoplasm of untreated cells was restricted to the cell membranes during the cultivation of cells in the presence of dB-cAMP, while expression of amylase persisted in the treated cells in a fashion similar to that in untreated cells. Moreover, both anchorage-independent and anchorage-dependent growth of the cells was markedly suppressed in the presence of dB-cAMP. After removal of dB-cAMP from the culture, the treated cells returned rapidly to the phenotype and growth rate of the untreated cells. These findings indicate that reversible conversion into cells with phenotypic features of neuronal cells of a human parotid adenocarcinoma cell line occurs in growth medium containing dB-cAMP.

Cytokeratin expression during AFB1-induced carcinogenesis.

The early stages of the carcinogenic process induced by aflatoxin B1 (AFB1) in rat liver during 24 weeks of feeding and the resulting tumours have been studied with respect to cytokeratin (CK) expression. A previously uncharacterized monoclonal antibody, MRCTU/J1, has been shown to recognize rat CK18 and together with antibodies against human CK8, 18 and 19, has been used to examine the possible lineage of tumour cells and also to identify the altered foci that might be most relevant to tumorigenesis. Results suggested that AFB1-induced transformation in liver may occur in more than one cell type, since tumours with the normal hepatocyte CK pattern and those with bile duct or oval cell CK phenotype were identified. Additionally, hepatocytes with a bile duct CK phenotype appeared during the early stages of carcinogenesis. The in vivo pattern of CK expression also appeared to be maintained in one normal and one hepatoma-derived cell line. Overexpression of CKs (particularly of CK19) was a much more selective marker for altered foci, compared to gamma-glutamyltranspeptidase, and was more consistently expressed at high levels in tumours, suggesting that it might be a more reliable way of identifying those cells involved in the transformation process.

[Immunohistological coexpression of keratin and vimentin in the epithelial neoplastic cells].

Filed formalin-fixed paraffin blocks of 128 cases of epithelial neoplasms were selected for immunohistochemical study of keratin and vimentin expression. The results showed that 35.1% (45/128) of different carcinomas expressed vimentin. The immuno-positivity of vimentin in thyroid carcinomas, ovarian carcinomas, prostatic adenocarcinomas, pulmonary carcinomas and malignant mesotheliomas were 81.8%, 42.8%, 66.7%, 30.5% and 53.4%, respectively. Carcinomas of breast, kidneys, salivary glands, adrenal glands and nasopharyngeal carcinomas also showed various degrees of positive reaction. The results suggest that an immunohistochemical positive vimentin reaction does not exclude histopathological diagnosis of carcinomas. The significance and noticeable aspects of immunohistochemical methods in histopathological diagnosis are also discussed.

[Immunohistochemical analysis of the liver using monoclonal antibodies against intermediate filaments]. / Imunohistochemická analýza pecene pomocou monoklonálnych protilátok proti niektorým typom intermediárnych filamentov.

The expression of some types of cytokeratin and vimentin in the liver was studied by using monoclonal antibodies to these types of intermediary filaments. Necrotic samples from livers without pathological finding were examined. A panel of 5 monoclonal antibodies, prepared in Czechoslovakia, to cytokeratins Nos. 7,8,18, and 19, as well as to vimentin was used. The findings confirmed the characteristic expression of cytokeratins 8 and 18 in hepatocytes and of cytokeratins 7, 8, 18, and 19 in epithelial cells of intrahepatic bile canaliculi, that monoclonal antibodies prepared in Czechoslovakia (LAMO, Brno and VUKEO, Brno) can be successfully used in immunochemical studies of intermediary filaments in the liver.

Isoprenylation is required for the processing of the lamin A precursor.

The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic for mevalonate. Moreover, inhibition of prelamin A processing by mevinolin treatment is rapidly reversed by the addition of exogenous mevalonate. Processing of prelamin A is, therefore, dependent on isoprenoid metabolism. Analysis of the conversion of prelamin A to lamin A by two independent methods, immunoprecipitation and two-dimensional nonequilibrium pH gel electrophoresis, demonstrates that a precursor-product relationship exists between prelamin A and lamin A. Analysis of R,S-[5-3H(N)]mevalonate-labeled cells shows that the rate of turnover of the isoprenoid group from prelamin A is comparable to the rate of conversion of prelamin A to lamin A. These results suggest that during the proteolytic maturation of prelamin A, the isoprenylated moiety is lost. A significant difference between prelamin A processing, and that of p21ras and the B-type lamins that undergo isoprenylation-dependent proteolytic maturation, is that the mature form of lamin A is no longer isoprenylated.

[Lymph node metastases of a Merkel-cell tumor of unknown origin: possibilities and limitations of fine-needle aspiration cytology]. / Metastasi linfoghiandolare di tumore a cellule di Merkel a sede primitiva non nota: possibilità e limiti della diagnostica citologica per aspirazione con ago sottile (FNA).

The authors report a case of lymph node metastasis of a Merkel cell carcinoma with unknown primary localization. The definitive diagnosis was posed histologically since the FNA report was--in this case--only "coherent with a small malignant cells proliferation".

[The intermediate filament-lamina-nuclear matrix system of BHK-21 cells].

We have employed collodial gold immuno-labelling in whole-mount cell and 2-D gel electrophoresis to demonstrate the intermediate filament (IF)-lamina-nuclear matrix (NM) system in BHK-21 (Baby Hamster Kidney) cells. Grown on grids, cells were gently extracted with salt solutions as previously described by S. Penman to preserve intact IF-lamina-NM systems. The extracted samples were fixed, postfixed, dehydrated and dried through the CO2 critical point, then examined under high voltage electron microscope (HVEM). The results revealed that the IF-lamina-NM system is a interconnecting network throughout the cell from cytoplasma to nuclear. The IF unit is 10 nm in diameter. IFs radiate away from the nuclear region into the spreading cytoplasm and the polarity of their distributing is obvious. The IF system closely connected to lamina. Immuno-gold labelling and 2-D gel proved that vimentin, a 55 KD protein (pI 5,6), is the major component of IFs in BHK-21 cells. Lamina can be precisely and specifically labelled with anti-lamin A, C proteins and as well as 2-D gel electrophoresis indicated that there are lamin A, B, C proteins in BHK-21 cells, whose molecular weights are 68 KD, 70 KD, 62 KD respectively. Its components are more complicated, but a few dots of NM proteins can be clearly distinguished in 2-D gel map, in which actin, a 45 KD protein (pI 4.5), might be involved. The nuclear matrix network was also clearly presented under HVEM. Its filaments can be labelled with anti-NM 298 KD protein precisely.

Neurofilament and chromogranin expression in normal and neoplastic neuroendocrine cells of the human gastrointestinal tract and pancreas.

To differentiate neuroendocrine (NE) neoplasms arising at different levels of the gut and pancreas, the authors studied the expression of neurofilament (NF) proteins and chromogranin (CR) in normal and neoplastic NE cells of the human gastrointestinal tract (GIT) (14 ileal/jejunal carcinoids, six appendiceal carcinoids, 11 rectal carcinoids) and pancreas (23 islet cell tumors). Among pancreatic islet cell tumors, those with middle molecular weight (NF-M)-positive cells were more abundant than those with high molecular weight (NF-H)-positive cells; nearly all of these tumors expressed CR. Although NF-M was abundantly expressed in greater than 50% of tumor cells in a subset of these tumors, only one of these tumors exhibited diffuse immunoreactivity with NF-H. Among rectal carcinoid tumors, NF-M and NF-H-positive cells were present in approximately the same number of tumors, yet only diffuse immunoreactivity to NF-H could be detected. Chromogranin immunoreactivity in greater than 50% of tumor cells was present in 74% of islet cell tumors, 93% of ileojejunal carcinoids, and 83% of appendiceal carcinoids, but only in a minority of rectal carcinoids (36%). Although ileojejunal carcinoid tumors rarely expressed NF-M and did not express NF-H, diffuse immunoreactivity with CR was present in nearly all of these tumors. None of the appendiceal carcinoid tumors expressed NF-M or NF-H, yet all of these tumors demonstrated immunoreactivity with CR. Neurofilament immunoreactivity was not detected in normal GIT and pancreatic NE cells, whereas CR immunoreactivity was always present. These results suggest that for NE neoplasms of the GIT and pancreas the differential expression of NF subtypes appears to be related to tumor site; and CR is a marker of most GIT and pancreatic NE neoplasms although NF may discriminate subtypes of GIT and pancreatic NE tumors. Neurofilament subtyping may be useful in the evaluation of the origin of NE tumors presenting as metastatic lesions.

The cDNA-deduced amino acid sequence for trichohyalin, a differentiation marker in the hair follicle, contains a 23 amino acid repeat.

Trichohyalin is a highly expressed protein within the inner root sheath of hair follicles and is similar, or identical, to a protein present in the hair medulla. In situ hybridization studies have shown that trichohyalin is a very early differentiation marker in both tissues and that in each case the trichohyalin mRNA is expressed from the same single copy gene. A partial cDNA clone for sheep trichohyalin has been isolated and represents approximately 40% of the full-length trichohyalin mRNA. The carboxy-terminal 458 amino acids of trichohyalin are encoded, and the first 429 amino acids consist of full- or partial-length tandem repeats of a 23 amino acid sequence. These repeats are characterized by a high proportion of charged amino acids. Secondary structure analyses predict that the majority of the encoded protein could form alpha-helical structures that might form filamentous aggregates of intermediate filament dimensions, even though the heptad motif obligatory for the intermediate filament structure itself is absent. The alternative structural role of trichohyalin could be as an intermediate filament-associated protein, as proposed from other evidence.

The epithelium of the human endolymphatic sac: immunohistochemical characterization.

A panel of monoclonal and polyclonal antibodies has been used to study the epithelium of the extraosseous part of the human endolymphatic sac (ES) by immunohistochemistry. The ES epithelium reacted with several epithelial markers such as Lu-5, different anticytokeratins, antiepithelial membrane antigen, and anticarcinoembryonic antigen. Unexpectedly, all epithelial cells also revealed a strong positive reaction for the mesenchymal marker vimentin and for S-100 protein. 'Neuroendocrine', a neurosecretory antigen, and neuron-specific enolase reactivity was detected in a few epithelial cells. The results support the assumption that the ES epithelium is metabolically active and capable of secretion and resorption. These findings are in keeping with results of functional experiments in animals. The demonstration of neurosecretory antigen and neuron-specific enolase in some cells indicate that the epithelium may also have paracrine functions.

[Cell biological characteristics of a human embryonal carcinoma cell line].

We examined the cell biological characteristics of a human embryonal carcinoma cell line. NEC 14, derived from a male germ cell tumor of testis origin. The following results were obtained. 1) The morphological characteristics of NEC 14 cells were small size, an increase in the N/C ratio and poor development of organelle and desmosome-like cell-cell junctions. The NEC 14 cells proliferated rapidly and the population doubling time in vitro was 17 hours. 2) The functional characteristics of NEC 14 cells were the localization of intermediate filaments such as keratin and vimentin, hCG secretion and tissue plasminogen activator and laminin synthesis and expression of cell surface antigens such as stage-specific embryonic antigen-3, trophoblast antigen and neuron cell surface antigen. 3) The mode of chromosome number was 58 and many abnormal and undetermined chromosomes were found in the NEC 14 cells. 4) Differentiation was observed in vitro and in the tumor tissues xenotransplanted into nude mice.

Intermediate filament expression in pituitary adenomas.

Seventy-five formalin-fixed and 18 alcohol-fixed pituitary adenomas were studied immunohistochemically using antibodies to keratin, vimentin, neurofilaments (NFs), glial fibrillary acidic protein, desmin, actin, S-100 protein and a variety of pituitary hormones. The pituitary adenoma cells were positive for keratin, vimentin and NFs (68 kDa and 160 kDa) and in a few instances there was co-expression of these three types of intermediate filaments (IMFs). The pattern of keratin-specific staining showed diffuse cytoplasmic or patchy paranuclear reactivity and of NF- or vimentin-specific staining showed fibrillar or patchy paranuclear reactivity. The patchy staining seemed to decorate the fibrous body. There was no correlation between the distribution of IMFs and pituitary hormones in pituitary adenomas except that melanocyte-stimulating-hormone-positive reactivity was limited to the NF-positive adenomas. The pattern of IMF staining did not depend on hormone production in adenomas.

Ubiquitin and phosphorylated neurofilament epitopes in ballooned neurons of the extraocular muscle nuclei in a case of Werdnig-Hoffmann disease.

The extraocular muscle nuclei in one case of Werdnig-Hoffmann disease were examined immunocytochemically using antibodies against phosphorylated neurofilament (pNF) and ubiquitin (UBQ). The oculomotor and trochlear nuclei showed several chromatolytic ballooned neurons. All ballooned neurons contained epitopes of pNF and UBQ. pNF were present mainly in the periphery of the cell in a ring-like shape and were occasionally seen in the center of some cells. On the other hand, the structures stained by the antibody to UBQ were small vesicles or granules and most of them were aggregated in the center of the cell. These distribution patterns of pNF and UBQ may be unique in Werdnig-Hoffmann disease, since similar patterns were reported in other types of neurons of Werdnig-Hoffmann disease but were not seen in two other motor neuron diseases: classical amyotrophic lateral sclerosis, and familial amyotrophic lateral sclerosis with posterior column and spinocerebellar tract involvement.

Transient cytokeratin expression in skeletal muscle during murine embryogenesis.

Cytokeratin expression was investigated in paravertebral skeletal musculature of 10 d and 18 d old embryos as well as in adult NMRI-mice. The muscular nature of the evaluated tissue was evidenced by their expression of vimentin and desmin. Binding moieties for cytokeratin antibodies (polyclonal and monoclonal) could be demonstrated only in muscle cells of 10 d old embryos. Concerning subtypes, the mouse equivalents of the human cytokeratins Nos. 8, 18 and 19 could be made probable. The importance of the transient cytokeratin expression in murine embryonal skeletal muscle cells is emphasized, because this intermediate filament type is expressed in rhabdomyosarcomas too.

Stratum corneum antibodies detected by hemagglutination are not directed against keratin intermediate filaments.

Autoantibodies to stratum corneum (SC) occur in virtually all normal adult human sera. These antibodies may be directed against various antigens of the SC. They have been detected by indirect immunofluorescence, passive hemagglutination (HA), immune adherence, and most recently by enzyme immunoassay and immunoblot methods. The purpose of our study was to examine whether antibodies to SC antigens as detected by passive HA are similar to the keratin intermediate filament (KIF) reactive antibodies. SC antigen preparation was prepared from psoriatic scales by the trypsin-phenol-water (TPW) extraction method. KIFs were prepared by 8 M urea extraction of normal callus or psoriatic scales. The anti-SC antibody titers of normal human sera were determined by passive HA before and after absorption with TPW-SC antigen preparation and upon absorption with KIFs. Similarly, titers of anti-KIF antibodies were determined on absorbed and unabsorbed sera by immunoblot assay. The results of this study indicate that the absorption of the sera with KIFs did not affect the titer of antibodies to TPW-extractable SC antigens whereas the titer of KIF antibodies dropped. KIF-reactive antibodies, on the other hand, were not affected by absorption with TPW-SC antigen, whereas the latter absorbed out the corresponding reactive antibodies. These results indicate that antibodies directed against SC antigen are different from the KIF-reactive antibodies.

Immunocytochemical and lectin-binding studies on Lafora bodies.

Antibodies to a range of intermediate filaments and lectins specific for several different carbohydrates were used to study Lafora bodies in two cases of Lafora disease. Positive staining of Lafora bodies was found with antibodies to 160 KD and 200 KD neurofilaments and to desmin. Positive staining with concanavalin A showed different patterns of inhibition with glucose and mannose, suggesting that the latter hexose contributes to the 10% non-glucose carbohydrate content of these bodies.

Analysis by confocal scanning laser microscopy imaging of the spatial distribution of intermediate filaments in foetal and adult rat liver cells.

Confocal scanning laser microscopy has been used to make three-dimensional observations of the spatial distribution of cytoskeleton intermediate filaments in rat liver hepatocytes, at various stages during foetal development and in the adult. Single and double immuno-labelling with fluorescein and Texas Red fluorescence have been used to study the intracellular spatial distribution of C18 cytokeratin and vimentin. Simultaneous confocal imaging with double-fluorescence emission requires an image processing step for the correction of 'contamination' effects due to the overlap between fluorescein and Texas Red emission spectra. At the pre-natal period (day 20 of gestation) each type of intermediate filament labelling is only present in a certain cellular category, C18 cytokeratin in hepatocytes and vimentin in mesenchymal cells. However, at the earliest developmental stages (day 12 of gestation), vimentin and cytokeratin seem to be found in the same type of cells, probably mesenchymal cells. Some striking developmental changes, associated with the differentiation of the liver parenchyma, are observed for both C18 cytokeratin and vimentin. In earlier foetal stages, C18 filaments are scarce, hazily labelled and randomly distributed inside the hepatocytic cytoplasm. Late during foetal development (days 18-20 of gestation), hepatocytic cytokeratin filaments are abundant, well individualized and sharply labelled. The hepatocytes are arranged in a muralium duplex architecture (two-cell-thick sheets) and the labelling intensity measured in the hepatocytic cytoplasm at the basal pole is double that measured at the sinusoidal pole, while, in the adult, hepatocytes are arranged in a muralium simplex architecture (one-cell-thick sheets) and cytokeratin filaments have a symmetrical distribution in relation to the nuclear region.

Expression of rat neurofilament proteins NF-L and NF-M in transfected non-neuronal cells.

Two cDNA clones fully encoding the rat neurofilament proteins NF-L and NF-M were subcloned into eukaryotic expression vectors behind the strong constitutive viral promoters from SV40 and Rous sarcoma viruses. Transient transfection of L tk- and Cos cell lines with these expression constructs resulted in cells expressing the neurofilament proteins in an intermediate filament-type pattern. Additionally, a putative juxtanuclear organizing center or region was observed in the transfected cells, most noticeable shortly after the transfection procedure. Stable transfections were performed on mouse L tk- and Swiss 3T6 cells using NF-L and NF-M constructs bearing an SV40 early promoter driven neomycin selectable marker. Although G418-resistant clones were recovered with both the NF-L and the NF-M constructs, only clones expressing immunofluorescently stainable amounts of NF-M were detected and established. Immunoelectron microscopic analysis revealed NF-M and vimentin proteins to be colocalized on the same intermediate filaments.

Ultrastructural analysis of cytoplasmic intermediate filaments and the nuclear lamina in the mouse plasmacytoma cell line MPC-11 after the induction of vimentin synthesis.

We examined cytoplasmic intermediate filaments (IFs) and the nuclear lamina in cells of the mouse plasmacytoma cell line MPC-11 (lacking both IF proteins and lamins A and C) after induction of vimentin synthesis with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) by means of whole-mount immunogold electron microscopy (IEM). The technique of IEM was modified to allow analysis of the cytoskeleton and nuclear lamina of cells grown in suspension culture employing antibodies against vimentin and lamin B. IEM showed that newly synthesized vimentin assembled into IFs which formed anastomosing networks throughout the cytoplasm, radiating primarily from the nucleus. The filaments decorated by gold-conjugated antibodies appeared to make contact with the lipid-depleted nuclear envelope residue either by directly terminating on it or through an indirect link via short fibers of varying diameter. Some filaments terminated on the subunits of the nuclear pore complexes but they did not pass through the pores. In the absence of lamins A and C, lamin B formed a nuclear lamina consisting of a globular-filamentous network anchoring the nuclear pore complexes.