Biomedical subjects

M M Mareel

Publications and source records attributed to M M Mareel.

107 records · Page 6Linked to original sources

PubMedDate not supplied

In vitro invasiveness of human bladder cancer from cell lines and biopsy specimens.

Aggregates prepared from cell lines established from a human transitional cell carcinoma of the urothelium (Hu 456) or from apparently normal urothelium before (Hu 609) and after phenotypic transformation (Hu 609T) were confronted with fragments of embryonic chick cardiac muscle in organ culture. In this assay a correlation was found between in vitro invasiveness of animal cell lines and their capacity to produce invasive tumours in syngeneic animals. The invasiveness of cells from established human urothelial lines was compared to the invasiveness of cells from established human urothelial lines was compared to the invasiveness of cells from fresh biopsy specimens of a normal urothelium, a non-invasive papilloma, and a metastasizing transitional cell carcinoma. Cells from all established lines (Hu 609, Hu 609T and HU 456) and from the biopsy specimens of the transitional cell carcinoma occupied and eventually replaced the cardiac muscle by contrast with cells from the normal urothelium or from the non-invasive papilloma. We concluded that the organ culture assay for invasiveness might be used to define malignancy of human bladder cell lines and to follow the various steps during the acquisition of invasiveness in vitro.

Adenocarcinoma↗

PubMedDate not supplied

Invasion in vitro by explants of Lucke renal carcinoma cocultured with normal tissue is temperature dependent.

Fragments of renal carcinoma of the northern leopard frog, Rana pipiens, were cocultured in vitro with small pieces of tadpole heart, frog heart and frog kidney with gyrotory shaking for up to 14 days at 21 degrees C and 28 degrees C. No invasion by renal carcinoma occurred in confrontation cultures at 21 degrees. However, the three normal tissues were invaded by renal carcinoma in confrontation cultures incubated at 28 degrees C. Invasion in vitro by histologically typical renal carcinoma is thus similar to temperature-dependent invasion by the renal carcinoma-derived cell line PNKT-4B and affords an opportunity for the identification of cell or biochemical events which may be activated at invasion-permissive temperature. Cell or biochemical events which are selectively activated and subsequently repressed as the renal tumor is incubated at invasion-permissive and invasion-restrictive temperatures become significant candidates as events involved in, or causal for, malignant invasion.

Animals↗

PubMedDate not supplied

Altered glycosylation in Madin-Darby canine kidney (MDCK) cells after transformation by murine sarcoma virus.

The changes in glycosylation of an immortalized epithelial cell line (MDCK) before and after progression towards a more malignant phenotype have been studied. The parental MDCK-3 cells were immortalized after long-term passage in vitro and have shown no tendency for spontaneous acquisition of malignancy-related phenotypes such as tumorigenicity, invasion and metastasis. They conserved morphological and functional characteristics of the epithelial tissue of origin. The ras-MDCK cells acquired the fully malignant phenotype after transformation with a Harvey murine sarcoma virus; they were immortalized, invasive in vitro and produced invasive and also metastatic tumors after subcutaneous injection into nude mice. Using immobilized lectins and gel chromatography, before and after liberation of O-linked glycans from the peptide moieties and also after removal of terminal sialic acid, we have found differences in the glycosylpeptides of both whole cells and cell surface trypsinates from ras-MDCK cultures as compared to the parental MDCK-3 cultures: (i) more sialic acid in the N-linked tri- and tetra-antennary structures; (ii) more fucosylation in the N-glycosylpeptides; (iii) more bi-antennary N-glycosylpeptides and less O-linked glycans; and (iv) a lower molecular weight of the O-linked glycans probably due to a decreased sialylation. It is concluded that alterations in sialylation and fucosylation of the cell surface exposed glycans accompanied progression of MDCK-3 cells towards a more malignant phenotype.

Animals↗

PubMedDate not supplied

Temperature-dependent malignant invasion in vitro by frog renal carcinoma-derived PNKT-4B cells.

The northern leopard frog, Rana pipiens, may be afflicted with a herpesvirus-transmitted renal carcinoma which has the interesting property that its metastatic behavior is temperature-related. PNKT-4B is a cell line derived from a pronephric carcinoma arising in a tadpole. We sought to ascertain if invasion of normal tissue by PNKT-4B cells in three-dimensional confrontation culture in vitro is similarly temperature-dependent. Normal fragments of tadpole and frog organs are invaded by PNKT-4B cells at 28 degrees C but not at 20 degrees C or 21 degrees C. PNKT-4B cells failed to invade tadpole tissues at 7 degrees C. A temperature critical for invasion was sought. Temperatures of 21 degrees C and cooler are invasion-restrictive and 23 degrees C and warmer are invasion-permissive under the conditions of this study. Identification of a critical permissive temperature allows for the characterization of biochemical events which may be activated at the same temperature. The biochemical changes, which are selectively activated and subsequently repressed as tumor cells are cycled through invasion-permissive and invasion-restrictive temperatures, become compelling candidates as reactions involved in, or causal for, malignant invasion.

Animals↗

PubMedDate not supplied

The flavonoid tangeretin inhibits invasion of MO4 mouse cells into embryonic chick heart in vitro.

Tangeretin, a flavonoid from citrus plants, was found to inhibit the invasion of MO4 cells (Kirsten murine sarcoma virus transformed fetal mouse cells) into embryonic chick heart fragments in vitro. The flavonoid appeared to be chemically stable in tissue culture medium, and the anti-invasive effect was reversible on omission of the molecule from the medium. Unlike (+)-catechin, another anti-invasive flavonoid, tangeretin bound poorly to extracellular matrix. It did not alter fucosylated surface glycopeptides of MO4 cells. Tangeretin seemed not to act as a microtubule inhibitor, as immunocytochemistry revealed no disturbance of the cytoplasmic microtubule complex. However, at anti-invasive concentrations of tangeretin, cell proliferation and thymidine incorporation appeared to be inhibited. When cultured on an artificial substrate, treated MO4 cells were less elongated, covered a larger surface area and exhibited a slower directional migration than untreated cells. From the decrease in ATP content in MO4 cells after tangeretin treatment, we deduce that this flavonoid inhibits a number of intracellular processes, which leads to an inhibition of cell motility and hence of invasion.

Adenosine Triphosphate↗

PubMedDate not supplied

Restored invasion of mouse MO4 cells into chick heart in vitro through mutual conditioning at reduced temperature.

Invasion of malignant mouse MO4 cells into embryonic chick heart fragments in confronting organ cultures was arrested for 7 days when the temperature of incubation was lowered to 28 degrees C. Afterwards invasion resumed and progression between days 10 and 17 at 28 degrees C was comparable to that between days 0 and 7 at 37 degrees C. This pattern of progression of MO4 cell invasion at 28 degrees C was unaltered when either MO4 cells or heart fragments or both were preincubated separately at 28 degrees C for 14 days before confrontation with each other. Invasion at 28 degrees C resumed only when MO4 cells and heart tissue had been in immediate contact for at least 7 days. Metabolic labelling with [3H]fucose showed a correlation in time between transient suppression of invasion and transient inhibition of incorporation of fucosylation-precursor molecules into glycoproteins by MO4 cells. The latter activity was far less temperature-sensitive in heart cells. Our observations suggest that metabolic cooperation between invading MO4 cells and heart tissue is essential for progression of invasion in vitro.

Animals↗

PubMedDate not supplied

Decreased fucose incorporation in cell surface carbohydrates is associated with inhibition of invasion.

Invasion of malignant MO4 cells into embryonic chick heart fragments in an organ culture assay was arrested for at least 7 days when the temperature was lowered to 28 degrees C. Prolonged culturing of MO4 cells at 28 degrees C on tissue culture substrates showed no recuperation of fucose incorporation into cell surface glycopeptides. However, invasion was restored after 10 days of organ culture in confrontation with chick heart tissue at 28 degrees C. A histoautoradiographic study showed that the regained capability to invade was accompanied by an increase in fucose labeling of the MO4 cells in the invading areas. At 28 degrees C the incorporation of [3H]fucose into total cell protein was drastically reduced, whereas [3H]leucine incorporation as a measure for protein synthesis was less affected. Cell surface glycopeptides, metabolically labeled with either fucose or glucosamine at 28 degrees C, showed a time-dependent decrease in the incorporation of fucose but not of glucosamine and no changes in overall size distribution. Low temperature did not reduce fucosyltransferase activity but the relative accumulation of fucose-1-P suggested inhibited conversion towards GDP-fucose. Moreover, mouse L cells which were incapable of invading chick heart tissue appeared also deficient in fucose incorporation, owing to low levels of fucosyltransferase activity. According to the results, fucosylation of surface carbohydrates may be required for invasive capacity and restored in MO4 cells invading at 28 degrees C by metabolic cooperation with the host tissue.

Animals↗

PubMedDate not supplied

An image analysis system for the quantification of invasion in vitro.

We have tested the value of a computer-assisted image analysis program for the quantitative study of invasion in vitro using experiments that were previously described semi-quantitatively. Mouse fibrosarcoma cell (MO4) aggregates were confronted with precultured fragments of embryonic chick heart in organ culture. Confronting pairs were fixed after 1, 2, 3 and 4 days, and processed for paraffin sectioning and immunostaining with an antiserum against chick heart. The image analysis system allowed separate quantification of two aspects of invasion, namely, occupation of the heart tissue by MO4 cells and degeneration of the invaded heart tissue. Complex combination of occupation and invasion added a qualitative aspect of invasion that has not been described previously and that revealed qualitative differences in invasion under various circumstances.

Animals↗

PubMedDate not supplied

Role of the host tissue in the anti-invasive activity of the alkyllysophospholipid, ET-18-OCH3, in vitro.

The alkyllysophospholipid, racemic-l-O-octadecyl-2-O-methylglycero-3- phosphocholine (ET-18-OCH3) was previously shown to inhibit invasion of malignant cells into precultured heart fragments (PHF) in vitro. In particular, pretreatment of PHF with 10 micrograms ET-18-OCH3 for 48 h was sufficient to induce in the host tissue resistance towards invasion by mouse MO4 cells. Resistance was obvious when MO4 cells were confronted either immediately (the pretreatment experiment) or after withdrawal of the drug 7 days prior to confrontation (the reversibility experiment). In the present study, the survival of PHF cells in the pretreatment and reversibility experiments was similar to that of untreated PHF cells as determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) test and by the PHF explantation test. The effective anti-invasive concentration was 6 micrograms/ml in the pretreatment experiment while 3 micrograms/ml was sufficient to inhibit invasion in the reversibility experiment. Induction of resistance towards invasion in pretreated PHF was shown to occur not only with MO4 cells but also with mouse LLC-H61 Lewis lung carcinoma and mouse BW-O-Li1 T-lymphoma cells. The increase in molecular weight of N-linked cell surface glycosylpeptides (N-GP) of PHF was apparent in the pretreatment experiment and was enhanced in the reversibility experiment. This effect was completely abolished in cells obtained from pretreated PHF which were converted into a cell suspension and further cultured as a monolayer on tissue culture plastic without drug for 7 days. The results reported here provide additional evidence for the causal involvement of N-GP of the PHF host tissue in the anti-invasive activity of ET-18-OCH3 in vitro.

Animals↗

PubMedDate not supplied

Effect of inhibitors of glycosylation and carbohydrate processing on invasion of malignant mouse MO4 cells in organ culture.

Inhibitors of glycosylation and carbohydrate processing were used to investigate the role of carbohydrates exposed at the cell surface in invasion. Malignant mouse MO4 cells were confronted with embryonic chick heart in organ culture, an assay shown to be relevant for a number of aspects of invasion in vivo. Tunicamycin (1.0 microgram/ml), 2-deoxy-D-glucose (100 mM), beta-OH-norvaline (1.0 mM), and Monensin (0.1 microgram/ml) reversibly inhibited the invasion of MO4 cells. At these concentrations the drugs also inhibited the growth of MO4 cells. 1-Deoxynojirimycin (10mM), swainsonine (0.4 microgram/ml), and Marcellomycin (0.1 microgram/ml) permitted invasion. Marcellomycin also reversibly inhibited the growth of MO4 cells. These results show that drugs known to interfere with the glycosylation or processing of carbohydrate chains of glycoproteins in different ways have different effects on the invasion of MO4 cells in vitro.

1-Deoxynojirimycin↗

PubMedDate not supplied

Inhibition of invasion of MCF-7/6 human breast carcinoma cells in vitro by Methanobacterium thermoautotrophicum extract.

Precultured embryonic chick heart fragments were confronted in vitro with various invasive tumor cell lines (MCF-7/6 human breast carcinoma variant, BW-O-LiI mouse T-cell lymphoma cells and MO4 virally transformed fetal mouse carcass cells) and with a non-invasive cell line (MCF-7/AZ human breast carcinoma variant). Confronting cultures were incubated in the presence of various methanogenic cofactors: Methanobacterium thermoautotrophicum extract, coenzyme F420, FO (7,8-didemethyl-8-hydroxy-5-deazariboflavin), F+ (5'-phosphate derivative of FO), or methanopterin. Histological analysis revealed that the Methanobacterium thermoautotrophicum extract inhibits invasion of MCF-7/6 human cells. At the moment it is not known which factor in the extract is responsible for this inhibition.

Breast Neoplasms↗

PubMedDate not supplied

Multiple differences between wild-type B16 melanoma cells and a wheat germ agglutinin resistant clone.

A low-metastatic, glycosylation-defective variant of the B16 murine melanoma was obtained by Tao and Burger (1977) through selection with wheat germ agglutinin. We found that variant and parental (wild-type) cell lines were equally invasive when confronted with precultured embryonic chick heart fragments in vitro. Also, a short-term in vivo arrest assay showed no significant differences. After intravenous injection, wild-type cells killed the recipient mice faster than did the variant cells. We were able to confirm the changes in glycosylation at the enzyme level. In addition, we showed that the pattern of endogenous lectins was strikingly different, at least at the quantitative level. We also looked at another set of receptor proteins, namely receptors for neurotransmitters coupled to adenylate cyclase. The response to the vasoactive intestinal peptide and prostaglandins was lower in the variant cells, which also had a delayed response to cholera toxin. Although most of the data can be explained by altered glycosylation in the variant cells, the large number of differences between variant and parent cells makes it difficult to identify the biochemical basis of altered metastatic behaviour. This might also be the case with other pairs of cells differing in metastatic activity.

Animals↗

PubMedDate not supplied

Metastatic T-cell hybridoma cells display target preference for invasion ('homing') in tissue culture models.

BW-O-Li1 murine T-lymphoma cells display target preference for invasion in two different in vitro models. In the precultured chick heart fragment (PHF) assay, BW-O-Li1 preferentially invaded into aggregates of MCF-7 mammary carcinoma cells rather than into PHFs. In a monolayer invasion assay (MIA), BW-O-Li1 cells preferentially invaded under 10 T1/2 mouse embryo cell monolayers rather than under MCF-7 monolayers. Thus, although BW-O-Li1 cells were perfectly able to invade into any of the targets presented, they migrated and accumulated preferentially in one of the targets when a choice was offered. We suggest that this in vitro 'homing' phenomenon can be exploited to investigate certain aspects of organ-specific metastasis.

Animals↗

PubMedDate not supplied

Antiinvasive activity of hexadecylphosphocholine in vitro.

The antiinvasive and related effects of hexadecylphosphocholine (HePC), a newly synthesized antitumor phospholipid, were studied on malignant murine MO4 cells in vitro and compared to the effects produced by racemic - 1 - 0 - octadecyl - 2 - 0 - methylglycero - 3 - phosphocholine (ET-18-OCH3), the prototype of ether lipids. The effects on cell survival produced by both drugs, determined through the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium-bromide test, was moderate at the antiinvasive concentration of 30 micrograms for HePC and 10 micrograms for ET-18-OCH3 per ml. Growth in suspension culture and directional migration from MO4 spheroids explanted on solid substrate was reduced in the presence of 30 micrograms HePC per ml. Invasion of MO4 cells into precultured heart fragments (PHF) was variably inhibited in the presence of 30 micrograms HePC per ml, while the antiinvasive effect on two epithelial lines was more complete. Invasion was also inhibited in PHF pretreated with 30 micrograms HePC and 10 micrograms ET-18-OCH3 per ml for 48 hours followed by confrontation with MO4 spheroids in drug-free medium. This inhibition of invasion was maintained when PHF was pretreated and kept in drug-free medium for 7 days before confrontation with MO4 spheroids. It was our impression that this phenomenon was more obvious with ET-18-OCH3 than with HePC. After pretreatment of PHF followed by 7-day incubation in drug free-medium, a larger shift towards higher molecular weight of the N-linked cell surface glycosylpeptides (N-GP) was observed with ET-18-OCH3 than with HePC. Removal of terminal sialic acid moieties abolished the shift in PHF pretreated with HePC or ET-18-OCH3 followed or not by further incubation in drug-free medium. The antiinvasive effect on the malignant epithelial cells was complete at 30 micrograms HePC per ml. Areas of differentiation in close contact with the PHF were obvious. We concluded that both ET-18-OCH3 and HePC had antiinvasive activity in vitro. For MO4 cells, this antiinvasive activity was less variable with ET-18-OCH3 than with HePC.

Animals↗

PubMedDate not supplied

Effect of oncogene transfection or passage in vivo on malignant phenotypes of rat2 cells.

Rat2 cells are thymidine kinase-deficient derivatives from the immortalized rat embryo cell line Rat1. They show no phenotypic correlates of malignancy in vitro and produce tumors in syngeneic Fischer rats after long latency periods. We have investigated how transfection with oncogenes would alter the in vitro and in vivo behavior of Rat2 cells. Thus we have manipulated Rat2 cultures in various ways. The cell lines obtained were categorized as parental, in vitro subclones, untransfected in vivo derivatives, non-oncogene (neor and tk) transfectants, oncogene (mutated c-Ha-ras, polyoma middle-T, FBR v-gag-fos-fox) transfectants, and in vivo derivatives of transfectants. They were tested in vitro for morphotype, colony formation in soft agar, growth in organ culture, invasion in organ culture, and in vivo for latency period of tumor formation, tumor growth rate, invasiveness, and metastasis. Differences between the consequences of various manipulations were found in the number of malignancy-related phenotypic alterations. The following trend could be deduced from our data: induction of invasiveness in organ culture by all manipulations; morphotypic transformation and shortening of tumor-latency period by all oncogene transfections and by passage with tumor formation in vivo; growth in organ culture and increased tumor growth rate in vivo by transfection with ras-, or fos-oncogenes and by passage in vivo. Metastatic capability (present in parental Rat2 cell tumors) and colony formation in soft agar (absent in Rat2 cells) were not affected by the present manipulations. We concluded that differences between the oncogene-transfectants and the untransfected in vivo derivatives do not lie in the expression of malignancy-related phenotypes but in the time needed to acquire them.

Animals↗

PubMedDate not supplied

Are oncogenes involved in invasion and metastasis?

In carcinogenesis, the acquisition of invasiveness and metastatic capability are the key steps towards malignancy. Clinical and experimental data suggest that invasion and metastasis necessitate cellular functions other than growth and by implication the activation of separate cellular genes. We review here data about the rôle of known oncogenes in the acquisition of invasive and metastatic capabilities. Major importance is paid to the question whether actual techniques for DNA-transfection, selection, and testing of invasion and metastasis are valid for the study of the rôle of oncogenes in invasion and metastasis. We conclude that, so far, such a rôle of oncogenes is uncertain, because the majority of cell populations used as recipients in transfection experiments are able to acquire invasiveness and metastatic capability in an apparently spontaneous manner.

Animals↗

PubMedDate not supplied

Action mechanisms of anti-invasive agents.

An anti-invasive activity has been observed with a number of agents in confronting cultures between invasive cell populations and embryonic chick heart fragments. Cytochalasins, microtubule inhibitors and dipyridamole act via intracellular targets. Inhibition of glycosylation of proteins, low temperature and alkyl lysophospholipids alter the plasma membrane. Flavonoids aim at extracellular targets. In a unifying hypothesis we postulate that invasion is due to lack of responsiveness to stop signals that normally retain cells within their tissue boundaries. Some of the anti-invasive agents act on cellular activities that are necessary for invasion; others might act on the stop signal, the perception of and/or the response to this signal.

Animals↗