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M M Mareel

Publications and source records attributed to M M Mareel.

At least 73 records · Page 4Linked to original sources
PubMed1986

Numerical evaluation of changes in the cytoplasmic microtubule complex of C3H mouse cells by optical diffractometry and of changes in cell shape by Fourier analysis.

MO mouse cells in culture on glass were treated with taxol, or nocodazole, or incubated at 4 degrees C to alter their cytoplasmic microtubule complex (CMTC). From each treated group and from an untreated group, 30 cells stained with an antiserum against tubulin, were photographed under the photomicroscope, and negatives were analysed by optical diffractometry. Differences between groups of cells were tested by variance analysis. Phase-contrast micrographs of the same cells were used for Fourier analysis of cell shape. Both types of analyses provided numerical objective data about changes in the CMTC and in cell shape that were typical for the kind of treatment. We conclude that optical diffractometry of immunostained cells and Fourier analysis of cell shape are complementary to photomicroscopy for the study of the CMTC in cell populations cultured on an artificial substrate.

Alkaloids↗
PubMed1986

Confrontation of an invasive (MO4) and a noninvasive (MDCK) cell line with embryonic chick heart fragments in serum-free culture media.

Confronting cultures of precultured embryonic chick heart fragments (PHF) with aggregates of malignant cells in vitro have been shown to be relevant for a number of aspects of tumor invasion in vivo. Preculture of the heart fragments, formation of cell aggregates, and subsequent culture of confronting pairs have so far been done only in serum-containing culture media. We describe here confronting cultures of PHF with invasive MO4 mouse cell aggregates or noninvasive MDCK dog kidney cell aggregates in serum-free media. Heart fragments precultured in the absence of serum seemed to be necrotic after confronting culture in serum-free media. However, preculturing in media supplemented with 10% fetal bovine serum allowed us to do subsequent confronting cultures in absence of serum. Cell aggregates were also prepared in serum-containing medium. MO4 cells occupied and replaced the heart tissue within 4 d, whereas MDCK cells remained at the periphery of the PHF. This indicates that serum-free confronting cultures can discriminate between invasive and noninvasive cells. The viability of individual PHF and cell aggregates cultured in the same way as in confrontations was ascertained by histology and by explantation and postculturing on a solid tissue culture substrate. Growth of the cultures was smaller in serum-free media than in media supplemented with 10% fetal bovine serum. The main advantage of serum-free culture conditions in vitro is the elimination of the influence of serum components on invasion, and the ability to examine the effect on invasion of drugs that are susceptible to inactivation by serum.

Animals↗
PubMed1986

Tumour invasion and metastasis: therapeutic implications?

Invasion and metastasis is the hallmark of tumour malignancy. Some aspects of invasion and metastasis with potential implications for tumour therapy are reviewed: the value of laboratory models; the acquisition of invasiveness and metastatic capability during carcinogenesis; the relationship between growth and invasion; clinical and experimental anti-invasive and antimetastatic agents. The value of joint experimental and clinical research is underscored.

Animals↗
PubMed1986

Invasiveness and metastatic capability of rat fibroblast-like cells before and after transfection with immortalizing and transforming genes.

Invasion in vitro and in vivo and spontaneous metastasis was investigated in cell lines before and after introduction of immortalizing (polyoma large-T and activated myc) genes and of transforming (polyoma middle-T and activated ras) genes in Fischer rat cells. Invasion in vitro was tested by confrontation of rat cells with embryonic chick heart fragments in organ culture. Invasion in vivo and metastasis was evaluated in nude mice and in syngeneic rats after injection of cells i.p. or s.c. in the flank and after implantation of cell aggregates s.c. in the tail. Rat cells were also analyzed for the presence of myc oncogenes, and for the expression of ras oncogenes. Cells from primary or low passage rat embryo (REF) cells were not invasive in vitro and did not produce tumors in vivo. Cell lines (LTRAT1, LTaRAT1) derived from REF cultures after transfection with plasmids encoding polyoma large-T antigens, behaved like REF cells. Cell lines (REFpEJgpt4, REFpEJmycN7) established from REF cultures after transfection with either a plasmid encoding an activated human ras protein or with the latter plasmid plus one containing an activated myc gene, were invasive in vitro and in vivo and produced invasive and metastatic tumors in syngeneic rats. Cell lines (FR3T3) established in an apparently spontaneous way were invasive in vitro and produced invasive tumors in vivo without metastasis. Derivatives of FR3T3 (FRLT1, MTT4, MMC1, and PyT21) transfected with plasmids encoding one or more of the polyoma antigens, differed from FR3T3 cells by a shorter latency period of tumor formation (less than 1 versus 1 to 3 weeks). Like FR3T3 tumors, FRLT1, MTT4, MMC1, and PyT21 tumors were invasive but not metastatic. Other spontaneously established lines (Rat1) were invasive and metastatic. Cells (Rat1pEJ6.6) derived from Rat1 cultures after transfection with a plasmid encoding an activated ras protein, showed shorter tumor latency periods (less than 1 versus 7 weeks). A thymidine kinase deficient Rat1 derivative (Rat2) was not invasive in vitro but produced invasive and metastatic tumors in vivo with long (9 to 21 weeks) latency periods. Rat2pT24B4 cells derived by us from Rat2 cells after transfection with a plasmid containing a mutated human ras gene (pT24), were invasive in vitro and in vivo as were cells derived from Rat2 tumors. We conclude from our experiments that invasiveness and metastatic capability are often acquired by established REF-derived cell lines in an apparently spontaneous way.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Effect of cancer-related and drug-induced alterations in surface carbohydrates on the invasive capacity of mouse and rat cells.

The effect of alterations in cell surface carbohydrates on invasion of mouse and rat cells into embryonic chick heart fragments in organ culture was studied. Matching pairs of malignant and nonmalignant cells, including all categories of carcinogenic induction (i.e., viral, chemical, or oncogenic), were compared for their alterations in cell surface carbohydrates and invasive behavior. Glycopeptides derived from the surface of malignant cells expressed cancer-related changes in carbohydrate composition, demonstrated by gel filtration chromatography as a shift in size distribution in comparison with those from nonmalignant counterparts. This phenotypic property strictly correlated with the acquisition of the invasive capacity. Morphological transformation of cells without simultaneous alteration in surface carbohydrates was, however, insufficient for invasion. To test the possible mechanistic role of altered surface carbohydrates in the invasive capacity of cells, the surface molecules of noninvasive cells were modified by incubation with an alkyl-lysophospholipid (racemic 1-O-octadecyl-2-O-methyl glycero-3-phosphocholine). Alkyl-lysophospholipid induced an increase in surface sialylation resembling the changes found in malignant and invasive cells. After pretreatment with alkyl-lysophospholipid, morphologically transformed but nonmalignant and noninvasive cells became able to invade chick heart tissue. These findings indicate that alterations in cell surface carbohydrates, induced by entirely different mechanisms, endowed cells with invasive capacity.

Animals↗
PubMed1985

Effects of tubulozole on the microtubule system of cells in culture and in vivo.

Light and electron microscopic investigations on mammalian cells in vitro and in vivo showed that tubulozole-C (R 46 846), the cis-isomer of tubulozole, a new synthetic anticancer drug, interfered with the structure and function of microtubules in both interphase and mitotic cells. The activity of this compound in experimental tumor systems can thus be explained partly by a direct antimitotic effect and partly by the disintegration of the normal subcellular organization of the nondividing cells. At concentrations which affect the microtubule system, tubulozole-C arrested directional migration of transformed cells and malignant invasion in a three-dimensional organ culture system. Investigations in vivo show that malignant L1210 leukemia cells are more susceptible to the antimicrotubular effect of tubulozole-C than are the normal leukocytes of the host. The trans-isomer of tubulozole (tubulozole-T, R 48 265), which has no antitumor activity in vivo, did not affect the microtubule system of cells in vitro or their capacity for directional migration or for malignant invasion.

Animals↗
PubMed1985

Antiinvasive effect of racemic 1-O-octadecyl-2-O-methylglycero-3-phosphocholine on MO4 mouse fibrosarcoma cells in vitro.

Alkyl-lysophospholipids have been shown to possess antitumoral activity in animal and in human tumors. Among them, racemic 1-O-octadecyl-2-O-methylglycero-3-phosphocholine (ET-18-OCH3) had an antimetastatic effect in experimental tumors. We investigated the effect of ET-18-OCH3 on invasion of MO4 mouse fibrosarcoma cells and on cellular activities possibly related to invasion in vitro. Ten micrograms of ET-18-OCH3 per ml permitted growth of MO4 cells to about 75% of controls and slightly reduced trypan blue exclusion. Directional migration inferred from the area covered by MO4 cells that had migrated from an aggregate on glass was not affected. Reassembly of microtubules after treatment with 1 microgram of Nocodazole per ml occurred normally in presence of ET-18-OCH3. Invasion was completely inhibited when MO4 cell aggregates were confronted with precultured fragments of embryonic chick cardiac muscle or with fresh embryonic chick lung fragments in culture on gyratory shaker in fluid medium with 10 micrograms of ET-18-OCH3 per ml. These experiments showed that ET-18-OCH3, in contrast with microtubule inhibitors, interfered with invasion of MO4 cells in vitro at concentrations that permitted growth and directional migration of MO4 cells. Fluorescence polarization studies with the lipophylic probe diphenylhexatriene indicated that the antiinvasive effect of ET-18-OCH3 was accompanied by an overall increase of membrane fluidity. We tentatively concluded that alterations of the MO4 cellular membranes are responsible for the antiinvasive effect of ET-18-OCH3.

Animals↗
PubMed1984

Enhanced recovery from growth inhibition in irradiated M04 spheroids invading into embryonic chick heart fragments in organ culture.

We have studied recovery from growth inhibition in irradiated M04 mouse fibrosarcoma spheroids using various post-irradiation culture conditions. Recovery after irradiation with 18 Gy was significantly higher in M04 spheroids confronting fragments of embryonic chick heart in suspension culture as compared to M04 spheroids confronting pieces of Gel-foam in suspension culture (p less than 0.0007) or to M04 spheroids explanted on coverslips in static culture (p less than 0.006). These observations suggest that the normal tissue might contribute to recovery from growth inhibition in irradiated M04 cell populations.

Animals↗
PubMed1984

Cytoplasmic microtubules of normal and tumor cells of the leopard frog. Temperature effects.

The cytoplasmic microtubule complex (CMTC) was examined in monolayer cultures of normal tadpole mesonephros, primary renal adenocarcinoma, and an established cell line derived from a pronephric renal adenocarcinoma (PNKT-4B) of the leopard frog, Rana pipiens. Immunocytochemistry revealed typical arrays of microtubules extending from the cytocentrum to the cell periphery in all three cell types when cultured at 28 degrees C; similar results were obtained at 20 degrees C. However, the CMTC was disorganized in both tumor types, in contrast to the retention of a typical CMTC in normal tissue cultured at 7 degrees C. The response of PNKT-4B cells differed from that of normal tadpole mesonephros when treated with the microtubule inhibitor drug nocodazole. At 28 degrees C, PNKT-4B and tadpole mesonephros cells lost their CMTC with nocodazole treatment, and both were able to reconstitute CMTC when nocodazole was removed. Similarly, both lost CMTC organization with nocodazole and culture at 70 degrees C. However, while normal cells could effect a recovery at 7 degrees C after the removal of nocodazole, PONKT-4B cells were unable to restructure CMTC under the same conditions. Metastasis in the frog renal adenocarcinoma is temperature-dependent, with an elevated prevalence of metastasis in tumor-bearing frogs maintained at 28 degrees C. Few metastatic colonies are detected in tumor-bearing frogs maintained at a low temperature (7 degrees C). Other studies have indicated that microtubules, which are essential for cell motility, play an important role in the invasion by tumor cells of normal tissue fragments in vitro. The effects of temperature on metastasis of the Lucke renal adenocarcinoma are consistent with temperature-mediated changes in tumor-cell CMTC.

Adenocarcinoma↗
PubMed1984

Interaction of malignant cells with salt-extracted cartilage in vitro.

A salt-extractable low-molecular-weight fraction has been held responsible for the resistance of cartilage to invasion by malignant cells. To test this hypothesis, we have confronted in vitro fragments from bovine articular cartilage, from bovine nasal septum, from chick embryonic tibia, or from human knee meniscus with cells from the following malignant lines: LICR-HN-4 human squamous cell carcinoma; B16BL6 mouse melanoma; Hu-456 human transitional cell carcinoma; TE-85 and SAOS-2 human osteosarcoma; and MO4 mouse fibrosarcoma. Human embryo lung cells and chick embryonic heart cells were used as nonmalignant counterparts. Confronting cultures using living cartilage and cartilage extracted with 3 M guanidinium hydrochloride were examined light microscopically and ultrastructurally after 1 to 14 days. Neither invasion of malignant cells into the matrix of living or salt-extracted cartilage nor breakdown of collagen was observed in these cultures. In contrast, both malignant and nonmalignant cells occupied preexisting spaces in the matrix, namely, cut chondrocyte lacunae, cartilage canals, and fibrillation clefts. We concluded from these experiments that salt extraction did not alter the resistance of cartilage to invasion by malignant cells in vitro. This conclusion does not support the opinion that salt-extractable factors are solely responsible for the resistance of cartilage.

Animals↗
PubMed1983

Invasion in vitro. Methods of analysis.

To understand the mechanisms of tumour invasion a number of in vitro assays have been developed, in which test cells (invasive or non-invasive) have been confronted with normal cells or tissues (the host) and cultured in various ways. We will discuss here the methods by which invasion can be judged in such assays. Histology is the method that is used successfully by pathologists for the evaluation of tumour invasiveness in vivo. The major difficulty is that the relationship between the non-invasive counterpart and the host tissue is not known in vitro or in vivo. Some authors have attempted to quantify invasion on histologic sections, but a generally accepted method is not yet available. The potential contribution of time lapse cinematography to the study of the kinetic aspects of invasion is obvious. Optical systems which overcome the relative lack of transparency of three-dimensional tissues, however, do not exist. Electron microscopy has contributed by providing details about the interactions between invasive cells on the one hand and normal cells as well as intercellular matrices on the other hand. Subpopulations of highly invasive and metastatic cells were collected after repeated migration through normal tissues in two-compartment assays. Attempts to evaluate the cytotoxic effect of invasive cells confronting radiolabelled cells or tissues have produced equivocal results. In contrast, measurements of radioactivity in the medium of labelled substrata have demonstrated the lytic effect of invasive cells on the extracellular matrix. It is concluded that further search for better methods to analyze and quantitate invasion is needed. So far, corroborative analysis by various methods seems to be the best policy.

Animals↗
PubMed1983

Interaction of three human malignant cell lines with chick hypoblast in culture.

The hypoblast (lower layer) was dissected from young chick blastoderms and explanted in vitro, where it formed an epitheloid sheet. Cells from the following malignant lines were explanted on top of the sheet both as aggregates and as cell suspensions: Hu456 human bladder carcinoma, SAOS-2 human osteosarcoma, LICR(LOND)-HN-4 laryngeal carcinoma. The interaction of the malignant cells with the hypoblast was studied by time lapse cinephotography, light microscopy, and transmission electron microscopy. All malignant cells penetrated through the hypoblast, so that a gradually enlarging hole formed in it. Apart from this common pattern of behaviour, the three types of malignant cells differed in their interactions with the hypoblast in the following ways. 1) Both the Hu456 and to a lesser extent the SAOS-2 cells brought about an initial retraction of the hypoblast so that a temporary cell-free space was formed. No such retraction occurred in response to the LICR-(LOND)-HN-4 cells. 2) Each of the three types of malignant cells migrated for some distance beneath the hypoblast, and in this area of underlap, there were differences in the amount and disposition of extracellular material. Thus, there was more extracellular material between the hypoblast and underlying SAOS-2 cells than between the hypoblast and underlying Hu456 cells, whilst there was no extracellular material between the hypoblast and underlying LICR(LOND)-HN-4 cells. Indeed, the hypoblast and LICR(LOND)-HN-4 cells often shared desmosomes. 3) When explanted as aggregates on hypoblast Hu456 and SAOS-2 cells left the corona and migrated as solitary cells underneath the hypoblast in contrast with control aggregates explanted on plastic. These cells which had migrated beneath the hypoblast were flatter than their corresponding control cells which had spread on the plastic substrate. The flatter cells appeared to have been using the extracellular materials as a substrate, rather than the plastic. Such differences in the migratory behaviour between experimental and control cultures were not observed with LICR(LOND)-HN-4 cells.

Animals↗
PubMed1983

Recovery from growth inhibition in irradiated MO4 spheroids: suspension cultures versus explanted cultures.

Spheroids of MO4 mouse fibrosarcoma cells were irradiated with single doses of photons between 1 and 50 Gy. Growth of irradiated spheroids was followed in suspension culture and after explantation on glass. We found that MO4 spheroids recovered from higher doses of irradiation when they were explanted on glass than when they were kept in suspension culture. These results suggest that irradiated MO4 cell populations may become anchorage-dependent for growth.

Animals↗
PubMed1982

Interaction of malignant MO4 cells with chick hypoblast in culture.

Malignant MO4 mouse fibrosarcoma cells were confronted with fragments of hypoblast from stage 4 (Vakaet 1970) blastoderms in different dispositions either permitting or preventing contact of the hypoblast with the tissue culture plastic. Explantation of an MO4 cell aggregate on top of 24 h-old-hypoblast caused retraction of the hypoblast. Contact inhibition of ruffling in hypoblast cells at the inner margin, by MO4 cells migrating radially from the aggregate, prevented closure of the hole brought about by the initial retraction. Disintegration of hypoblast was not observed. Migration of MO4 cells during the first 24 h was faster from an aggregate explanted on top of hypoblast than from an aggregate explanted on tissue culture plastic. Hypoblast fragments explanted on top of confluent layers of MO4 cells attached and spread during the first 12 h. Later, the hypoblast progressively disintegrated. Here, MO4 cells accumulated underneath the hypoblast. We concluded 1) that the hypoblast attracted the MO4 cells by influencing their pattern of migration and 2) that contact with the artificial substrate allowed survival of hypoblast confronting malignant MO4 cells. Ultrastructural analysis suggested that formation of extracellular material played a major role in the interaction between the normal tissue and the malignant cells.

Animals↗
PubMed1982

Vinblastine, Vincristine and Vindesine: anti-invasive effect on MO4 mouse fibrosarcoma cells in vitro.

Inhibition of the invasiveness of MO4 mouse fibrosarcoma cells by the vinca alkaloid, vinblastine (VLB), vincristine (VCR) and vindesine (VDS), has been examined in vitro. At doses between 0.006 microgram/ml (minimal effect) and 0.1 microgram/ml (complete inhibition) these drugs interfered with the invasion of MO4 cells from an aggregate confronting a fragment of embryonic chick heart in three-dimensional culture. We have also examined the effect of these drugs on the following activities of MO4 cells: growth, directional migration and assembly of the cytoplasmic microtubule complex. Growth and directional migration were affected by the same doses of vinca alkaloids as invasion. In contrast with the vinca alkaloids, 5-fluorouracil at 1 microgram/ml inhibited growth but allowed directional migration and invasion. At a dose of 0.3 microgram/ml VLB, VCR and VDS interfered with the assembly of cytoplasmic microtubules, as visible after immunocytochemical staining with tubulin antiserum. Ultrastructural analysis demonstrated that inhibition of invasion in three-dimensional culture corresponds with abolishment of the cytoplasmic microtubule complex. Anti-invasive concentrations of VLB, VCR and VDS represent clinically achievable plasma concentrations. We concluded that the anti-invasive effect of the vinca alkaloids may contribute to their antitumor activity.

Animals↗
PubMed1982

Glycosylated podophyllotoxin congeners: loss of microtubule inhibition and permission of invasion in vitro.

Podophyllotoxin (PPT) and its glycosylated congeners, 4'-demethylepipodophyllotoxin 9-[4,6-O-(R)-ethylidene-beta-D-glucopyranoside] (VP-16-213) and 4'-demethylepipodophyllotoxin 9-[4,6-O-(R)-thenylidene-beta-D-glucopyranoside] (VM-26), were studied for their effects on the following activities of MO4 mouse fibrosarcoma cells in vitro: growth as an aggregate in culture on a gyrotory shaker, directional migration from an aggregate explanted on glass, organization of the cytoplasmic microtubule complex as inferred from immunostaining with an antiserum against tubulin, and invasion into fragments of 9-day-old embryonic chick cardiac muscle. At concentrations that inhibited growth (greater than or equal to 0.03 microgram/ml), PPT arrested directional migration, abolished the cytoplasmic microtubule complex, and interfered with invasion. VM-26 (0.1-1.0 microgram/ml) and VP-16-213 (1-30 micrograms/ml) interfered with growth but permitted directional migration, organization of the cytoplasmic microtubule complex, and invasion. These observations imply that microtubule inhibitors are anti-invasive because they interfere with the assembly of the cytoplasmic microtubule complex and not because they inhibit growth.

Animals↗