Establishment of a continuous cell line from a human carcinoid of the small intestine (KRJ-I)

A new continuous cell line from a human malignant carcinoid of the small intestine (KRJ-I) was established. The cells showed morphological and immunocytochemical features of the tumor of origin and expressed estrogen receptors. The cells are growing as a suspension, forming multicellular aggregates and spheroids. Electron microscopy confirmed the presence of neuroendocrine granules. Dose-dependent growth inhibition was observed after incubation with 5-azacytidine. Cytogenetic analyses of the tumor of origin, the cell line KRJ-I and a liver metastasis KRJ-II revealed clonal tetraploidy and clonal loss of the Y-chromosome and chromosome 19.

New continuous cell-line from human medullary-thyroid carcinoma - sinj - phenotypic analysis and invivo carcinogenesis

SINJ is a new continuous human cell line derived from a lymph node metastasis of a probably sporadic medullary thyroid carcinoma. It is compared to MTC-SK, another medullary thyroid carcinoma cell line, established earlier (1). SINJ has been continuously cultivated in vitro for two years. The cells grow as a suspension of single cells and cell clusters. Repeated immunocytochemistry showed positive immunoreactivity with antibodies to CT, CGRP and GRP. The maintenance of NSE and chromogranins were proved. Northern blot analysis confirmed endocrine activity at mRNA level. Flow cytometry of 27 SINJ - clones showed 25 diploid and two tetraploid subpopulations. Cytogenetic analyses strengthened these findings. According to DNA analysis the cells are free of SV40 sequences. Tumorigenicity was proved in nude mice. The new cell line SINJ has potential use for in vitro studies of medullary thyroid carcinomas in sporadic as well as hereditary forms - the MEN2A syndrome.

The role of mechanical forces and adenosine in the regulation of intestinal enterochromaffin cell serotonin secretion

Enterochromaffin (EC) cells of the diffuse neuroendocrine cell system secrete serotonin (5-HT) with activation of gut motility, secretion, and pain. These cells express adenosine (ADORA) receptors and are considered to function as mechanosensors. Physiological pathways mediating mechanosensitivity and adenosine responsiveness remain to be fully elucidated, as do their roles in inflammatory bowel disease (IBD) and neoplasia. Pure (98-99%) FACS-sorted normal and IBD human EC cells and neoplastic EC cells (KRJ-I) were studied. IBD-EC cells and KRJ-I overexpressed ADORA2B. NECA, a general ADORA receptor agonist, stimulated, whereas the A2B receptor antagonist MRS1754 inhibited, 5-HT release (EC50 = 1.8 × 10-6 M; IC50 = 3.7 × 10-8 M), which was associated with corresponding alterations in intracellular cAMP levels and pCREB (Ser133). Mechanical stimulation using a rhythmic flex model induced transcription and activation of Tph1 (tryptophan hydroxylase) and VMAT₁ (vesicular monoamine transporter 1) and the release of 5-HT, which could be inhibited by MRS1754 and amplified by NECA. Secretion was also inhibited by H-89 (PKA inhibitor) while Tph1 and VMAT₁ transcription was regulated by PKA/MAPK and PI₃K-mediated signaling. Normal and IBD-EC cells also responded to NECA and mechanical stimulation with PKA activation, cAMP production, and 5-HT release, effects reversible by MRS1754. EC cells express stimulatory ADORA2B, and rhythmic stretch induces A2B activation, PKA/MAPK/IP3-dependent transcription, and PKA-dependent secretion of 5-HT synthesis and secretion. Receptor expression is amplified in IBD and neoplasia, and 5-HT release is increased. Determination of factors that regulate EC cell function are necessary for understanding its role as a mechanosensory cell and to facilitate the development of agents that can selectively target cell function in EC cell-associated disease.

Adenosine A2A and A2B receptor expression in neuroendocrine tumours: potential targets for therapy

The clinical management of neuroendocrine tumours is complex. Such tumours are highly vascular suggesting tumour-related angiogenesis. Adenosine, released during cellular stress, damage and hypoxia, is a major regulator of angiogenesis. Herein, we describe the expression and function of adenosine receptors (A(1), A(2A), A(2B) and A(3)) in neuroendocrine tumours. Expression of adenosine receptors was investigated in archival human neuroendocrine tumour sections and in two human tumour cell lines, BON-1 (pancreatic) and KRJ-I (intestinal). Their function, with respect to growth and chromogranin A secretion was carried out in vitro. Immunocytochemical data showed that A(2A) and A(2B) receptors were strongly expressed in 15/15 and 13/18 archival tumour sections. Staining for A(1) (4/18) and A(3) (6/18) receptors was either very weak or absent. In vitro data showed that adenosine stimulated a three- to fourfold increase in cAMP levels in BON-1 and KRJ-1 cells. The non-selective adenosine receptor agonist (adenosine-5'N-ethylcarboxamide, NECA) and the A(2A)R agonist (CGS21680) stimulated cell proliferation by up to 20-40% which was attenuated by A(2B) (PSB603 and MRS1754) and A(2A) (SCH442416) receptor selective antagonists but not by the A(1) receptor antagonist (PSB36). Adenosine and NECA stimulated a twofold increase in chromogranin A secretion in BON-1 cells. Our data suggest that neuroendocrine tumours predominantly express A(2A) and A(2B) adenosine receptors; their activation leads to increased proliferation and secretion of chromogranin A. Targeting adenosine signal pathways, specifically inhibition of A(2) receptors, may thus be a useful addition to the therapeutic management of neuroendocrine tumours.

Development of standardized cell culture conditions for tumor cells with potential clinical application

BACKGROUND

Tumor cell lines have enormous value for the study of different aspects of cancer biology and have also recently gained great importance in autologous cell-based anti-tumor therapies. However, the use of these cells is still limited because in vitro growth is hampered by suboptimal culture conditions and current media contain fetal bovine serum (FBS), which poses serious safety concerns regarding clinical application.

METHODS

To address this drawback, we aimed to develop a strategy for optimization of the culture medium for human medullary thyroid carcinoma (MTC) cell lines as a model system. We combined the general cell screening system (GCSS), which continuously measured the growth behavior of cells in a 96-well plate format, with statistically based experimental designs.

RESULTS

The results obtained clearly demonstrated that, just by changing the composition of the basal medium, a significantly enhanced growth rate could be observed, and by subsequent addition of several substances a serum-free cell culture medium could be developed. This medium allowed the propagation of two MTC cell lines comparable with conventionally used serum-supplemented medium.

DISCUSSION

We present a fast and easy way to screen for substances that are essential for tumor cell growth in vitro. Furthermore, these tumor cells can be adapted to culture conditions that allow the use of the cells in safe cell-based therapies. This is of utmost importance because of increasing regulatory requirements.

Effect of pan-inhibitory somatostatin analogues, topotecan and bortezomib on the human enterochromaffin neoplastic cell line KRJ-I

13144

Background: Effective therapeutic options to inhibit the growth and limit the spread of carcinoid tumors are limited. Somatostatin (SST) analogs that target specific SST receptors, though often effective at alleviating the symptoms of carcinoid disease, have limited cytostatic effects on carcinoid tumor cells. The anti-proliferative activity of 2 pan-inhibitory SST analogues and lanreotide were evaluated using the human small intestinal carcinoid cell line KRJ-I. The effects of novel cytotoxic agents used in Phase II carcinoid clinical trials, topotecan (topoisomerase-I inhibitor) and bortezomib (proteasomal inhibitor), were also measured. Methods: The SST receptor profile of KRJ-1 cells was determined using hybridization to U133A chips and confirmed by real time PCR with Taqman probes for SSTR1–5. KRJ-1 cells in serum-free medium were treated with 100 pM to 10 μM of the SST pan inhibitory analogs, BIM-23A719 and BIM-23A779, or lanreotide (BIM-23014C) and 1nM to 1 μM of topotecan or bortezomib for 72 hrs. The 3-(4,5-dimethylthiazole-2 yl)-2,5 diphenyltetrazolium bromide (MTT) assay was used to evaluate proliferation which was expressed relative to control cells (no agent added). Results: KRJ-I cells co-express mRNA for SSTR2 and SSTR3 (mean levels ± SEM 0.48 ± 0.13 and 0.73 ± 0.19 copy/copy GAPDH respectively). BIM-23A719 inhibited growth maximally (15 ± 2% of control) at ICmax = 10 pM, whereas BIM-23A779 inhibited growth maximally (11 ± 1% of control) at 100 pM. Lanreotide had no significant inhibitory effect on cell growth and resulted in increased MTT conversion at high concentrations (10 μM). Topotecan and bortezomib inhibited growth maximally at 23 ± 1.5%; ICmax = 50 nM and 32 ± 1.6%; ICmax = 50 nM respectively. Conclusions: Cytotoxic agents are more effective but less sensitive than pan-inhibitory somatostatin analogues for the inhibition of proliferation of the small intestinal carcinoid KRJ-I cell line. The specific SSTR2/3/5 analogue, lanreotide, had no inhibitory effect on KRJ-I proliferation. These results suggest that the KRJ-I cell line is more sensitive to analogues targeting a pan-somatostatin receptor profile than cytotoxic agents. The former may have potential as adjuvant agents for treatment of GI carcinoid tumors.

[Table: see text]

geNorm assessment of the efficacy of novel reference genes ALG9, TFCP2 and ZNF410 compared to GAPDH for real time normalization in GI carcinoids

20052

Background: Robust quantitation of potential clinical marker genes using quantitative real-time PCR (Q RT-PCR) is critically dependent on accurate normalization. Although GAPDH has historically been used for normalization, its expression has been shown to vary widely between different tissues and experimental conditions. Additionally, conventional normalization strategies based on a single housekeeping gene can lead to large normalization errors. The determination of a panel of genes that have robust expression in the experimental system being studied is therefore essential to ensure accurate normalization and interpretation of results. Methods: Based upon the availability of large-scale gene databases, we developed methodology to identify highly expressed genes (mean log-transformed expression levels: 4–8 in all samples) with low variability (S.D. < 0.22) in a Affymetrix U133A dataset of 36 gastrointestinal tumors and normal tissues. Eight novel candidate reference genes were identified and their expression levels established by Q RT-PCR in an independent set of GI tissue samples (n = 24). The geNorm tool was used to identify the most stably expressed set of genes amongst the 8 candidate genes. The expression levels of 3 potential GI tumor marker genes, namely the adhesin MAGE-D2, the metastasis-associated MTA1, and the mitosis regulator, NAP1L1, were normalized to GAPDH or geNorm and compared. Results: geNorm identified 3 genes, ALG9, TFCP2 and ZNF410, as the most robustly expressed control genes. GAPDH, in contrast, exhibited the highest variability and was considered the least stable gene of the nine evaluated. Two previously-identified target genes, MAGE-D2 and MTA1, were significantly elevated (p < 0.05) in malignant tumor samples (vs normal GI samples) when normalized by geNormATZ but not when normalized using GAPDH. NAP1L1 was only over-expressed in small intestinal carcinoids (normalized to geNormATZ). Expression levels of this gene were high in normal gastric mucosa. Conclusions: We provide a robust basis for the establishment of a reference gene set using GeneChip data and provide evidence for the clinical utility of identifying reference genes using the geNorm approach in GI neuroendocrine tumors.

No significant financial relationships to disclose.

Establishment of human fibroma cell lines from a MEN1 patient by introduction of either hTERT or SV40 early region

Establishment of tumor cell lines as model systems for studying tumor biology or as a part of immunotherapeutic anti-cancer strategies is of high importance, whereby the highest possible preservation of the original tumor cell phenotype is a prerequisite for these aims. Since overexpression of the catalytic subunit of human telomerase (hTERT) is known to minimally alter the cellular phenotype, we focused on the establishment of cell lines derived from human fibroma from a MEN1 patient by ectopic expression of hTERT. Additionally, a cell line was generated by introduction of the early region of SV40 (SV40 ER). Both approaches resulted in continuous cell lines, and neither T1-LOHG (hTERT) nor SV1-LOHG (SV40 ER) showed a transformed phenotype. While SV40 ER-transfected cells underwent dramatic changes in morphology and growth characteristics, hTERT-expressing cells indeed retained a phenotype highly similar to the parental cells. Nevertheless, hTERT overexpression resulted in increased growth rates after about 70 population doublings (PD) and alterations of mRNA levels of genes associated with tumor pathogenesis. Thus, our data suggest that ectopic hTERT expression leads to immortalization of LOHG-F, sustaining many characteristics of the non-transfected counterparts, but continuous growth in vitro is associated with changes of the cellular phenotype.

Cytotoxic activity of camptothecin and paclitaxel in newly established continuous human medullary thyroid carcinoma cell lines

At the time of diagnosis, more than one quarter of patients with medullary thyroid carcinoma (MTC) has distant metastases. Only few of these patients can be cured by surgery. Standard chemotherapy is characterized by low response rates and short response time. The establishment of eight human MTC cell lines provides a new basis for in vitro investigation of cytotoxic drugs. Camptothecin (CPT) and paclitaxel, which never have been investigated in the treatment of MTC, were tested for their cytotoxic profile in comparison with the clinically ineffective dacarbazine. Eight MTC cell lines were established from seven patients with MTC. IC(50) values were calculated from dose-response relationships using cell counts and a formazan dye assay (WST-1). IC(50) values were 3.5 +/- 1.2 nmol/liter for CPT and 8.2 +/- 1.9 nmol/liter for paclitaxel. Dacarbazine showed no reduction of cell proliferation at concentrations 10-fold higher than clinically achievable. Given peak plasma concentrations of 65 +/- 20 nmol/liter for CPT and 1 micro mol/liter for paclitaxel, these promising in vitro results provide a basis for the performance of clinical trials in patients with advanced MTC.

Vitamin E binding protein afamin protects neuronal cells in vitro

Afamin, an 87 kDa human plasma glycoprotein with specific binding properties for vitamin E (alpha-tocopherol) was recently characterized (Jerkovic, 1997; Vögele, 1999). In the present study the in vitro effects on neuronal cells of native human Afamin, of Afamin pre-loaded with vitamin E (Afamin+), and of vitamin E were investigated. Isolated cortical chicken neurons were maintained either under apoptosis-inducing low serum conditions or exposed to oxidative stress by the addition of H2O2 or beta-amyloid peptide(25-35). Afamin and vitamin E synergistically enhance the survival of cortical neurons under apoptotic conditions. Furthermore, Afamin alone protects cortical neurons from cell death in both experimental settings. Therefore, the plasma glycoprotein Afamin apparently displays a neuroprotective activity not only by virtue of binding and transporting vitamin E but also on its own.

Stimulation of autologous antitumor T-cell responses against medullary thyroid carcinoma using tumor lysate-pulsed dendritic cells

Dendritic cells (DCs) have attracted wide interest because of their unique capacity to elicit primary and secondary antitumor responses. We have generated autologous tumor lysate-pulsed DCs from three patients with medullary thyroid carcinoma (MTC) and tested them for their ability to stimulate cytotoxic T-cell responses against autologous MTC tumor cells in vitro. The aim of our investigations was to evaluate the potential efficacy of DC-based immunotherapy in patients with MTC. DCs were generated from peripheral blood monocytes using GM-CSF and IL-4 (immature DCs) or GM-CSF, IL-4, and TNFalpha (mature DCs). Our results indicate that mature tumor lysate-pulsed DCs are able to elicit a human leukocyte antigen class I-restricted cytotoxic T-cell response against autologous MTC tumor cells, whereas immature tumor lysate-pulsed DCs do not stimulate significant antitumor activity. We feel that our data may be relevant for future clinical trials of active immunotherapy using tumor lysate-pulsed DCs in patients with MTC who have residual or distant disease after surgical treatment. The fact that mature DCs displayed a substantially higher capacity to stimulate autologous antitumor T-cell responses than immature DCs underlines the importance of a maturation step in immunotherapy protocols based on DCs.

Comparative genomic hybridization and cytogenetic analysis in a bronchial adenoma: three clones with different chromosomal aberrations

Classical chromosomal analysis and comparative genomic hybridization (CGH) were performed in a tubular bronchial gland adenoma. Trisomy of chromosomes 2, 11, 18 and 20 and clonal loss of Y were found in cultured cells derived from two different kryotubes; this was also confirmed by CGH from one of these tubes. Cells from two other tubes, investigated by CGH only, showed gains and losses of parts of chromosome 11q in one, and in the second additional gain of the distal portion of 9q and 17q, respectively. CGH analysis of tumor DNA extracted from paraffin-embedded sections showed no chromosomal imbalances. In cell culture growth the advantage of specific clones probably altered the clone distribution. This study highlights the risk of cytogenetic analysis based on cell cultures only.

The affinity of MCF7 breast cancer cells to hyaluronan substrates of different molecular weight and concentrations in an in vitro model

The affinity of MCF7 breast cancer cells to hyaluronan (HA) was investigated in an in vitro model. The cells form a tightly adhering monolayer on native HA with a concentration of 5 mg/ml. On native HA at higher concentrations the cells reduce their adhesion to the substrate in favor of increased intercellular bonds, resulting in a cluster-like aggregate that tends to detach from the substrate. Aggregate formation is accomplished after 12 h incubation. The phenomenon is independent of the CD44 receptor. Degradation of native HA by hyaluronidase abolishes aggregate formation even at high HA concentrations in favor of formation of a firmly adhering monolayer. This model may help to understand tumor spread on HA tissue structures and may explain therapy successes with hyaluronidase in tumor patients.

Cytogenetic and CGH studies of four neuroendocrine tumors and tumor-derived cell lines of a patient with multiple endocrine neoplasia type 1

A malignant insulinoma (LOHG-I), a carcinoid of the lung (LOHG-L), a parathyroid adenoma (LOHG-NSA), and a fibroma (LOHG-F) were obtained from a patient with multiple endocrine neoplasia type 1 (MEN1). Long-term cultures were established. Essential neurobiological properties of the cell lines were proven immunocytochemically and by electron microscopy. Molecular analysis of the germline DNA showed a 4 bp deletion in exon 3 of the MEN1 gene. Cytogenetic and CGH analyses of the tumors/tumor cell lines revealed diploidy and balanced and unbalanced structural aberrations different for each tumor. Chromosomes 6q21, 11q and 17q were most frequently involved in clonal structural aberrations.

First continuous human pheochromocytoma cell line: KNA. Biological, cytogenetic and molecular characterization of KNA cells

Pheochromocytomas are rare tumours, with an incidence of 1-2 per million which arise from chromaffin cells of the adrenal medulla. They occur sporadically or as part of dominantly inherited cancer syndromes like multiple endocrine neoplasia 2 (MEN2A and 2B) and others. Continuous cell lines, not available so far, are essential tools for studies in these tumours. A continuous cell line (KNA) was established from a sporadic pheochromocytoma of the right adrenal gland of a 73-year-old woman. The KNA cells grow as suspensions of spheroids and show the morphological and immunocytochemical characteristics of neuronal chromaffin cells, such as neuroendocrine granules, and positive reactions to chromogranin- and related peptide-, neuron specific enolase and vasoactive intestinal peptide antibodies. Neurite-like processes are formed after addition of nerve growth factor. Chromosomal analyses revealed a diploid (46,XX,n = 50) to hypodiploid (43-45,XX,n = 15) karyotype. In hypodiploid metaphases most frequently #19, #17, #21 and #22 were missing. Chromosome arms 1p and 4q showed apparently consistent interstitial deletions: 6q, 8q, 13q and 22q showed clonal interstitial deletions. The cell line shows a heterozygous sequence variant TGC (cysteine) to TGG (tryptophan) in codon 611 in exon 10 of the RET proto-oncogene. So far, PC-12, a rat adrenal pheochromocytoma, has been the only continuous pheochromocytoma cell line available. KNA represents the first report on a human continuous pheochromocytoma cell line, the first report of structural chromosome aberrations in pheochromocytomas and the first report of a RET mutation TGC to TGG in exon 10 of the RET proto-oncogene in a sporadic pheochromocytoma.

Mutation of the RET protooncogene in sporadic medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) occurs sporadically or as part of the inherited cancer syndrome multiple endocrine neoplasia (MEN) type 2. In MEN 2A, germline missense mutations are found in one of five cysteine codons within exons 10 and 11 in the extracellular domain of the RET protooncogene. In MEN 2B, germline mutations occur in codon 918 (exon 16) within the catalytic core of the tyrosine kinase domain. To determine if RET mutations similar to those in MEN 2A and 2B play a role in the pathogenesis of sporadic MTC, we analysed 71 sporadic tumours comprising 68 primary tumours and three cell lines, for mutations in RET exons 10, 11, and 16. We found that 23% of sporadic MTC had RET codon 918 mutations, while only 3% had exon 10 mutations, and none had mutations in exon 11. We found no exon 16 mutations in MTC from 14 MEN 2A cases. Thus, exon 10 and 11 mutations, commonly found in familial MTC and MEN 2A, rarely occur in sporadic MTC; somatic mutation of RET codon 918 appears to play a role in the tumourigenesis of a significant minority of sporadic MTC but not MEN 2A tumours. In addition to their biological interest, these findings may have some clinical application in determining whether a patient presenting with isolated MTC is truly sporadic or is part of an inherited cancer syndrome.

Chromosome typing in lymphangioleiomyomatosis of the lung with and without tuberous sclerosis

Two cases of lymphangioleiomyomatosis (LLM) of the lungs are compared, one with tuberous sclerosis and the other representing an isolated lung involvement. An increased frequency of complex chromosomal rearrangements was found in peripheral lymphocytes of the patient with tuberous sclerosis, in comparison to the patient with isolated lymphangioleiomyomatosis. Telomeric associations were found in cultured pulmonary smooth muscle cells from the patient with isolated LLM.

Chromosome typing in lymphangioleiomyomatosis of the lung with and without tuberous sclerosis

Two cases of lymphangioleiomyomatosis (LLM) of the lungs are compared, one with tuberous sclerosis and the other representing an isolated lung involvement. An increased frequency of complex chromosomal rearrangements was found in peripheral lymphocytes of the patient with tuberous sclerosis, in comparison to the patient with isolated lymphangioleiomyomatosis. Telomeric associations were found in cultured pulmonary smooth muscle cells from the patient with isolated LLM.

Cytogenetic analysis by chromosome painting using DOP-PCR amplified flow-sorted chromosomes

A novel polymerase chain reaction (PCR) technique has been combined with chromosome flow sorting to characterise two lymphoblastoid cell lines and one medullary thyroid carcinoma cell line carrying translocations close to the locus for multiple endocrine neoplasia type 2A (MEN 2A). Five hundred copies of the derivative chromosome(s) were flow sorted from each cell line and amplified by degenerate oligonucleotide-primed-polymerase chain reaction (DOP-PCR). This generated pools of DNA sequences corresponding to the abnormal chromosomes, which were then used as probes in fluorescence in situ hybridisation (FISH) experiments on normal metaphase cells. The resultant chromosome paints revealed the portions of the normal chromosomes related to those involved in the translocations. By this technique, translocation breakpoints in bands p15, q11.2, and q21 of chromosome 10 were defined in the above cell lines, in two cases refining previous cytogenetic data. This study shows that flow sorting of aberrant chromosomes and chromosome painting can be used as a rapid aid to cytogenetic analysis, particularly in cases of difficult karyotypes, such as tumours. Furthermore, the DOP-PCR technique described here will have applications to other areas of genome analysis, such as cloning of new markers; its design will allow a general and representative amplification to occur from any starting DNA in any species.

Establishment and characterization of continuous cell line MTC-SK derived from a human medullary thyroid carcinoma

Tumor cells of a human medullary thyroid carcinoma were isolated and propagated in tissue culture. Several cell lines with different morphology developed from the primary culture, among others a fibroblast-like growing cell line (MTC-F) and a cell line growing as a suspension of single cells and spherical cell clusters (MTC-SK). The MTC-SK cell line was serially propagated for 90 passages, over 3 years. When examined at different times throughout the in vitro period, MTC-SK exhibited properties characteristic of medullary thyroid carcinomas: the cells maintained their epithelioid morphology; endocrine granules were demonstrated in the cytoplasm by electron microscopy; in situ hybridization confirmed the production of calcitonin- and bombesin-mRNA (gastrin releasing peptide); the cells revealed positive immunoreactivity with antibodies to calcitonin, calcitonin gene-related peptide, and bombesin. The in vitro properties of the MTC-SK cells corresponded to the results obtained from the tissue of origin. Cytogenetic studies of the MTC-F cell line revealed a supernumerary metacentric chromosome (20?). In the MTC-SK cell line the predominant findings were terminal chromosomal rearrangements most frequently concerning chromosome 11p, i.e., the locus of the calcitonin and calcitonin gene-related peptide genes and the H-ras oncogene, and a characteristic instability of the centromeric region of chromosome 16 and somatic pairing of the homologous chromosomes 16.

Oncogene expression in a medullary thyroid carcinoma

We report the expression of Ha-ras, fos, c-myc and N-myc mRNA in a human medullary carcinoma of the thyroid gland, both in primary tumor and lymph node metastasis, as demonstrated by in situ hybridization and Northern blot analysis. A significant difference in the oncogene expression in the primary tumor and the metastasis was not observed. Tumor tissue revealed a significant overexpression of Ha-ras, c-myc and N-myc mRNA as compared to the normal thyroid gland. The amount of fos mRNA expression in non tumorous thyroid gland did not significantly differ from tumor tissue, sis, fms and abl mRNA expression was not detectable in tumor tissue and non tumorous thyroid gland. We conclude, that the (over)expression of the oncogenes Ha-ras, c-myc and N-myc may be associated with initiation and progression of medullary thyroid carcinoma. Similar studies on additional cases of human medullary thyroid carcinoma will be necessary to reveal further information.

[In-vivo marking of human tumors using BUDR for flow-cytometry determination of kinetic cell parameters]

The flow-cytometry results of solid, human tumours are reported which were labelled with Bromodeoxyuridine in vivo. The preparation of the single cell suspension is prescribed. The S-phase percentage could be determined exactly in all cases but one. It is a rapid procedure which gives results in one day and the in vivo labelling had no adverse effects.

[Flow cytometric measurements of in vivo incorporated bromodeoxy- uridine into the DNA of experimental and human tumors]

A new cell kinetic method was used in vivo in an experimental mouse tumour and in human tumours of the oral cavity for the first time. The incorporation of BUdR into cells in the S-phase that are actively synthesizing DNA enables the determination of the rate of DNA synthesis from the amount of BUdR-related fluorescence using monoclonal antibody and the proportion of S-phase cells which are actively engaged in synthesis. The application of BUdR to the patients and the preparation of the tumour is reported.

The labelling index of human and mouse tumours assessed by bromodeoxyuridine staining in vitro and in vivo and flow cytometry

Bromodeoxyuridine (BrdUrd) incorporation and flow cytometry were used to measure human tumour kinetic parameters in vitro and in vivo. The technique was validated by comparison of labelling index estimates of mouse tumours in vivo and in vitro using BrdUrd and flow cytometry with tritiated thymidine (3HdThd) autoradiography. Similar labelling indices were obtained with both in vivo and in vitro incorporation into DNA of the two different precursors. Measurements of human tumour labelling indices were similar following in vitro incubation with either BrdUrd or 3HdThd. The use of BrdUrd allowed the visualization of a population of S-phase cells that did not appear to incorporate BrdUrd or 3HdThd. The human tumour labelling indices obtained with BrdUrd incorporation were similar to previously reported values using autoradiography studies. Preliminary studies demonstrated that significant human tumour labelling could be achieved with an intravenous injection of 500 mg BrdUrd.

The effect of nerve growth factor (NGF) on the catecholamine contents of two human pheochromocytomas in tissue culture

Two further cases of human pheochromocytomas were kept in tissue culture for three months. The cultures were parted into two groups: one group was treated with nerve growth factor (NGF), the other group served as the control. The catecholamines in the medium were determined radioenzymatically (Da Prada). NGF-treatment led to lower contents of adrenaline, noradrenaline and dopamine. Cultures without NGF had higher levels. Electron micrographs showed catecholamine granula during the whole culture period. NGF treated cultures contained more catecholamine granula than the untreated cultures. Though the number of catecholamine granula was increased by the NGF-treatment, the medium contained less catecholamines than in untreated cultures. It may be concluded that NGF influences the liberation of adrenaline, noradrenaline and dopamine in tissue culture: though NGF treated cells contained more catecholamine granula, the catecholamines were retained in the pheochromocytoma cells.

Effects of adrenaline-tablets on rat heart cells in tissue culture at normal and raised temperature

Primary cultures of rat heart cells were incubated at 37 degrees C or 39.5 degrees C. For permanent treatment with adrenaline recently developed tablets were added to the cultures. After 10 hours the cell counts, glucose, lactate, LDH, alpha-HBDH and GOT were determined. Permanent adrenaline-application led to a decrease of cell counts, an increase of lactate, LDH, alpha-HBDH and GOT. The results indicate an injured membrane function of rat heart cells. Raised temperature sensitized the cells for adrenaline-treatment.

Long-term tissue culture of human pheochromocytomas

Two human pheochromocytomas were cultured for long periods. One was cultured for a year, the other is still growing after a cultivation time of seven months. Though decreasing with the age of cultures the cells contained catecholamines all the time. Catecholamines were demonstrated by electron microscope, by fluorescence histochemistry and by Vulpian's and Da Prada's methods. Both pheochromocytomas were responsive to Nerve Growth Factor and showed dose-dependent development of neurite-like processes.