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G Prodi

Publications and source records attributed to G Prodi.

At least 19 recordsLinked to original sources
PubMed1989

Myogenic differentiation of human rhabdomyosarcoma cells induced in vitro by antineoplastic drugs.

The effect of various antineoplastic drugs (1-beta-D-arabinofuranosylcytosine, 5-azacytidine, cisplatin, dactinomycin, epirubicin, vincristine, and the activated metabolite of cyclophosphamide, mafosfamide) on cell differentiation in vitro was investigated using a human alveolar rhabdomyosarcoma cell clone, RMZ-RC2. These cells are able to differentiate spontaneously from small mononuclear proliferating elements to terminal, extremely elongated multinuclear structures resembling myotubes; morphological differentiation is accompanied by the expression of myosins, in particular the embryonic isoform, which was used in this study as a specific marker of myogenic differentiation. The proportion of differentiated myosin-positive cells, which was around 10-15% in control cultures 10-15 days after seeding, was increased by some drug treatments up to 30-40%; the proportion of multinuclear elements was also increased. 1-beta-D-arabinofuranosylcytosine and 5-azacytidine were the most effective drugs, while dactinomycin had no effect; other molecules ranked in between. Since significant increments were usually observed after treatment with drug doses inhibiting cell growth, the kinetic behavior of the absolute number of myosin-positive cells or nuclei was analyzed to assess whether some effects could be due to a negative selection of proliferating, undifferentiated cells. This appeared to be the case for vincristine and epirubicin, while 1-beta-D-arabinofuranosylcytosine, 5-azacytidine, and, to a lesser degree, mafosfamide and cisplatin actually seemed to increase differentiation ability.

Antineoplastic Agents↗
PubMed1989

In vivo and in vitro production of haemopoietic colony-stimulating activity by murine cell lines of different origin: a frequent finding.

The production of colony-stimulating factor (CSF) by murine transformed cells was investigated in 10 cell lines derived from spontaneous or chemically induced tumours and from cells transformed by SV40 or Moloney-MSV; histologic types included carcinomas, sarcomas and melanoma. Nine of 10 supernatants contained CSF activity as judged by in vitro proliferation and differentiation of normal murine monocytic and granulocytic progenitors in agar cultures. Tumours induced with CSF-producing cells caused alterations of haemopoiesis which can include leukocytosis, granulocytosis and splenomegaly. Haemopoietic alterations were also evident in the absence of a local tumour in mice bearing large experimental lung metastases. Production of CSF seems to be a frequent finding among murine cell lines, and its biological and immunological consequences on host-tumour relationships should be taken into account.

Animals↗
PubMed1989

Tumorigenic and metastatic ability of SV40-transformed BALB/c cell lines and MHC antigen expression.

Tumorigenic and metastatic potential were studied in relation to class I MHC expression in four different SV40-transformed BALB/c cell lines. All the lines studied, tumorigenic or not, expressed both H-2Kd and Dd, so MHC antigens did not seem to be involved in the control of SV40-transformed cells' growth in vivo. Lung metastases were observed in all tumour-bearing mice. Cells cultured after in vivo passage, obtained either from tumour tissue or from individual lung metastases, still expressed similar levels of H-2d antigens, thus suggesting that tumour growth and metastasis do not occur through the selection of variants with altered MHC expression.

Animals↗
PubMed1989

Metabolic activation and covalent binding to nucleic acids of pentachloroethane as short-term test of genotoxicity.

The in vivo covalent binding of 14C-pentachloroethane to DNA, RNA and proteins of rats and mouse organs was detected 22 hr after i.p. injection. The covalent binding index, calculated on the liver labeling was comparable to those of compounds considered as weak-moderate initiators. Like other haloalkanes, 14C-pentachloroethane was bioactivated in in vitro cell-free system by both microsomal and cytosolic enzymatic fractions from mouse and rat organs to react covalently with DNA and other macromolecules. The binding extents obtained from in vitro incubation and the binding values detected after in vivo administration of labeled pentachloroethane were comparable each other and showed a high correlation with oncogenic potency index of this compound. This result confirms the efficiency of in vitro binding as short-term test of genotoxicity prediction.

Animals↗
PubMed1988

Binding of hexachloroethane to biological macromolecules from rat and mouse organs.

Hexachloroethane (HCE) binds to macromolecules of rat and mouse both in vivo and in vitro after metabolic activation. The covalent binding index (CBI) to liver DNA in vivo is comparable to that of compounds classified as weak-moderate initiators and is of approximately the same order of magnitude as those of other halocompounds such as 1,2-dichloroethane. HCE is bioactivated in vitro by microsomal enzymatic systems from murine liver and kidney and, to a greater extent, by cytosolic fractions from all assayed organs. HCE is less reactive than 1,1,2,2-tetrachloroethane, which is more toxic and oncogenic. The ability of hexachloroethane and five other chloroethanes to react covalently with mouse liver DNA both in vivo and in vitro parallels the relative oncogenic potency of these hepatocarcinogenic chemicals in mouse liver.

Animals↗
PubMed1987

The covalent binding of 1,1,2,2-tetrachloroethane to macromolecules of rat and mouse organs.

The in vivo interaction of the hepatocarcinogen 1,1,2,2-tetrachloroethane (1,1,2,2-TTCE) with DNA, RNA, and proteins of male Wistar rats and BALB/c mice was measured 22 hr after i.p. injection. Covalent binding index (CBI) to liver DNA was about 500 and was comparable to those of carcinogens classified as moderate initiators. It was higher than those of other chloroethanes, even than that of 1,2-dichloroethane (1,2-DCE), a symmetrically substituted haloethane whose genotoxicity has been widely demonstrated. In in vitro cell-free systems, 1,1,2,2-tetrachloroethane was bioactivated by mixed-function oxidase(s) and glutathione-S-transferase(s) (GSH-T) from microsomal and cytosolic fractions of rat and mouse liver and, to a lesser extent, of mouse lung. The in vitro activation led to formation of reactive species capable of binding to exogenous DNA and to the subcellular constituents of enzymatic fractions. These data, along with previous literature reports, provide sufficient evidence of 1,1,2,2-TTCE genotoxicity.

Animals↗
PubMed1987

Evidence of DNA binding activity of perchloroethylene.

14C-Perchloroethylene is covalently bound to DNA, RNA and proteins of rat and mouse organs in vivo after ip injection. Covalent Binding Index values are typical of weak-moderate and weak initiators, for mouse and rat liver, respectively. The greater amounts of labelings detected in mouse liver and in rat kidney macromolecules are consistent with the known toxic and carcinogenic actions of this compound. In vitro binding of perchloroethylene to nucleic acids and proteins proceeds through the involvement of the P-450-dependent mixed function oxidase system from liver microsomes. Kidney, lung and stomach microsomal fractions are uneffective. Cytosolic enzymes from all assayed organs are much more efficient than liver microsomes in bioactivating the compound. GSH addition to liver microsomal system greatly enhances binding extent. This observation suggests that GSH plays a role in the binding of perchloroethylene metabolites as for symmetrically substituted haloethanes.

Animals↗
PubMed1987

Growth and metastasis in allogeneic hosts. Lack of H-2-negative or somatic hybrid variant selection.

In vitro cultured B16 melanoma cells, which were previously found to have an impaired expression of H-2Kb and Db (as evaluated by antisera absorption assay), were used to study growth and metastasis in allogeneic mice in relation to H-2 expression. The possible emergence of somatic hybrids with host cells was also examined. B16-A cells grown subcutaneously in allogeneic BALB/c mice (H-2d) did not show a lack of H-2b expression, nor the acquirement of H-2d antigens was found. Spontaneous lung metastases were found in about 30% of BALB/c mice with progressing B16 tumor. Single lung metastases showed higher H-2b levels than cells from the respective tumors, and did not express host H-2 antigens. Tumor take was concomitant to the rise of an anti-H-2b humoral response: disease outcome was independent from the serum titer. B16-A cells injected intravenously in BALB/c mice gave rise to lung colonies; different colonies showed a wide range of H-2b antigens levels and no H-2d expression. Lung colonization capacity in normal allogeneic BALB/c mice was significantly higher than in syngeneic C57BL/6 mice. Both syngeneic and allogeneic mice, when pretreated with cyclophosphamide (CY) to reduce natural killer cell activity, showed a significant increase in lung colonization by B16-A cells. CY-treated C57BL/6 mice showed significantly higher numbers of lung colonies than CY-treated BALB/c mice. In conclusion, B16 growth and metastasis in the allogeneic environment do not seem to be determined by a selection of H-2-negative variants or by the emergence of somatic hybrids with host cells.

Animals↗
PubMed1986

RMZ: a new cell line from a human alveolar rhabdomyosarcoma. In vitro expression of embryonic myosin.

The RMZ cell line was established from a bone marrow metastasis of a human alveolar rhabdomyosarcoma. Since the beginning of the in vitro culture, RMZ cells showed differentiation-related morphological heterogeneity: actively proliferating polygonal or spindle-shaped cells were observed along with a few multinucleated myotube-like structures and giant cells, frequently multinucleated. All these cell types were still present after over 40 passages. A set of clonal derivatives has been obtained from the second in vitro subculture. All the clones showed the same morphological heterogeneity of the parental cells, but differed from one another in the degree of differentiation. Multinucleated myotube-like structures were strongly stained by anti-desmin antibody; most mononuclear cells were weakly stained. About 80% of RMZ and cloned cells were scored as desmin-positive in cytocentrifuged preparations. The expression of embryonic myosin heavy chain, specifically recognized by the monoclonal antibody BF-G6, was found in RMZ cell line and was localised in the myotube-like structures. Only a few giant cells and rare mononucleated polygonal cells were stained. The average proportion of BF-G6 positive cells in cytocentrifuged preparations was of about 6% of the total RMZ cells. In the two RMZ clones studied, the expression of embryonic myosin was correlated to the proportion of myotube-like structures: a BF-G6 positivity of 35% was found in the most differentiated one.

Cell Count↗
PubMed1986

Effect of antioxidants on mutagenesis induced by DMBA in human cells.

The effect of vitamin A palmitate (VAP), vitamin A acetate (VAA), 2,3-tert-butyl-4-hydroxyanisole, and 2,6-di-tert-butyl-p-cresol (BHT) on mutagenesis induced by 7,12-dime-thylbenz[a]anthracene (DMBA) was examined in a human epithelial-like cell line. Cultures were exposed to DMBA with or without the antioxidant compound, and mutation frequencies were determined by selection against diphtheria toxin. A clear inhibition of mutagenesis was observed particularly with VAA and BHT.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1986

Interaction of halocompounds with nucleic acids.

The binding of epichlorohydrin, 1,2-dichloroethane, 1,2-dibromoethane, chlorobenzene, bromobenzene, and benzene to nucleic acids and proteins of different murine organs was studied in in vivo and in vitro systems. The extent of in vivo enzymatic activation of brominated compounds was higher than that of chlorinated chemicals. Aryl halides were bound mainly to liver DNA whereas interaction of alkyl halides with DNA of liver, kidney, and lung gave rise to similar binding extent. In vitro activation of all chemicals was mediated by microsomal P-450-dependent mixed function oxidase system which is present in rat and mouse liver and, in smaller amount, in mouse lung. Activation of alkyl halides by liver cytosolic GSH-transferases even occurred. The relative reactivity of chemicals in vivo, expressed as Covalent Binding Index (CBI) to rat liver DNA, was: 1,2-dibromoethane greater than bromobenzene greater than 1,2-dichloroethane greater than chlorobenzene greater than epichlorohydrin greater than benzene. On the whole, it agreed with in vitro activation of chemicals, with genotoxicity data from other short-term assays and also with oncogenicity of benzene, epichlorohydrin, 1,2-dichloroethane, and 1,2-dibromoethane. CBI values of chlorobenzene and bromobenzene gave the first clear evidence of genotoxicity and of possible carcinogenicity of these two chemicals.

Animals↗
PubMed1986

1,1,2-Trichloroethane: evidence of genotoxicity from short-term tests.

At 22 hr after ip injection into adult male Wistar rats, 1,1,2-trichloroethane was covalently bound to DNA, RNA and proteins of the liver, kidney, lung and stomach, as has been found with various weakly carcinogenic halo compounds. The extent of interaction of 1,1,2-trichloroethane with mouse liver DNA was much higher than that with rat liver DNA. This result provides evidence of a correlation between adducts formation and species susceptibility to hepatocarcinogenesis (only the mouse is sensitive to the oncogenic effect of this compound). Interaction with DNA mediated by murine liver microsomes occurred in vitro. No particular differences between the two species were found. In vitro binding was enhanced (approximately 5-fold) by pretreatment in vivo with phenobarbitone but was suppressed by addition of 2-diethylamino-ethyl-2,2-diphenylvalerate X HCl in vitro. Cytochrome P-450 was, therefore, involved in the interaction process. Glutathione suppressed the microsome-mediated interaction, acting as a "scavenger" of reactive intermediate(s). Murine lung microsomes were less effective bioactivators than liver microsomes for the interaction with DNA and microsomal RNA, but not microsomal protein. Kidney and stomach microsomes were ineffective, as were cytosolic fractions from all of the assayed organs of the two species. The extent of in vitro interaction of 1,1,2-trichloroethane with synthetic polyribonucleotides was of the same order of magnitude as that with DNA. The results represent further clear evidence for genotoxicity of 1,1,2-trichloroethane.

Animals↗
PubMed1986

Short-term tests of genotoxicity for 1,1,1-trichloroethane.

Covalent binding of 14C-1,1,1-trichloroethane to macromolecules from rat and mouse liver, kidney, lung and stomach was analyzed under the same experimental conditions previously utilized in studying 1,1-dichloroethane and 1,1,2-trichloroethane. Labeling of DNA, RNA and proteins was very low both in in vivo interaction and in in vitro microsome-mediated binding. Interaction proceeded through the involvement of the P-450-dependent mixed function oxidase system from liver microsomes and, to a lesser extent, from lung microsomes. Covalent Binding Index of 1,1,1-trichloroethane in liver DNA was typical of very weak initiators. However, overall evaluation of the short-term assays available for 1,1,1-trichloroethane leads to limited evidence of genotoxicity. On the other hand, the evidence of 1,1,1-trichloroethane carcinogenicity in animals is still inadequate.

Animals↗
PubMed1986

Clones with different metastatic capacity and variant selection during metastasis: a problematic relationship.

Cells from TS/A, a metastasizing line derived from a spontaneous BALB/c mouse mammary adenocarcinoma, were injected either sc or iv in syngeneic mice, and the resulting lung metastases or lung colonies were briefly cultured in vitro and reinjected in mice by the same route; this procedure was repeated 10 times. All the variants obtained did not show a metastatic capacity higher than the parental cell line. Moreover, they gave a number of metastases significantly lower than that produced by high metastatic clones selected in vitro from TS/A. The number of lung colonies obtained with intravenously selected (COL) variants was significantly higher than that obtained with subcutaneously selected (META) variants, TS/A, or in vitro-selected clones; this was already observable after the first cycle of selection. Both COL and META variants did not show the in vitro growth properties of the in vitro-selected high metastatic clones. In conclusion, both intravenous and subcutaneous selection procedures did not lead to an enrichment in high metastatic populations, even if such populations were present in the parental line and had been cloned in vitro; only the intravenous procedure selected high-colonizing variants.

Animals↗
PubMed1985

In vivo and in vitro binding of benzene to nucleic acids and proteins of various rat and mouse organs.

Benzene binds to macromolecules of various organs in the rat and mouse in vivo. Labelling of RNA and proteins is higher (1 order of magnitude) than DNA labelling, which is low in many organs (liver, spleen, bone marrow and kidney), and negligible in lung; no difference between labelling of rat and mouse organs was found. The covalent binding index (CBI) value was about 10, i.e. typical of genotoxic carcinogens classified as weak initiators. In vitro binding of benzene to nucleic acids and proteins is mediated by hepatic microsomes, but not by microsomes from kidney, spleen and lung, or by cytosol from whatever organ. Nucleic acid binding can be induced by pretreatment with phenobarbitone (PB) and suppressed in the presence of SKF 525-A, of cytosol and/or GSH or of heat-inactivated microsomes. Labelling of exogenous DNA is low and is similar in the presence of rat or mouse microsomes in agreement with the low interaction with DNA measured in vivo.

Animals↗
PubMed1985

In vitro microsome- and cytosol-mediated binding of 1,2-dichloroethane and 1,2-dibromoethane with DNA.

Metabolic activation of 1,2-dichloroethane (DCE) and 1,2-dibromoethane (DBE) to forms able to bind covalently with DNA occurs in vitro either by way of microsomal or cytosolic pathways. The involvement of these two pathways is variable with respect to species or compound tested. Rat enzymes are generally more efficient than mouse enzymes in bioactivating haloalkanes and DBE is more reactive than DCE. This parallels both the previous report on in vivo comparative interaction and the higher genotoxicity of DBE.

Animals↗