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Biomedical subjects

F Traganos

Publications and source records attributed to F Traganos.

At least 91 records · Page 5Linked to original sources
PubMed1991

Caffeine modulates the effects of DNA-intercalating drugs in vitro: a flow cytometric and spectrophotometric analysis of caffeine interaction with novantrone, doxorubicin, ellipticine, and the doxorubicin analogue AD198.

Exposure of L1210 cells to DNA-intercalating antitumor drugs Novantrone (mitoxantrone; 20 ng/ml), doxorubicin (0.5 micrograms/ml), ellipticine (5 micrograms/ml), or the doxorubicin analogue AD198 (0.4 micrograms/ml), for 1 h, results in inhibition of cell proliferation, arrest of cells in the G2 phase of the cell cycle, and an increase in the number of cells entering higher DNA ploidy. These effects are significantly reduced when 5 mM concentrations of the methylxanthines caffeine or pentoxifylline are present either simultaneous with, or, in some cases, when added for 1 h immediately following pulse exposure to the drug. Both caffeine and pentoxifylline alone (5 mM) have little effect on cell growth or cell cycle progression. The possible mechanism of cell protection against intercalating drugs provided by caffeine was studied spectrophotometrically by measuring the interaction between Novantrone and the caffeine chromophore and in a model system using permeabilized L1210 cells and measuring the effect of caffeine in reducing binding of the intercalating dye acridine orange to cellular DNA and RNA. The data indicate that the observed protection of cells against intercalating drugs by caffeine or pentoxifylline is most likely a consequence of the direct interaction between the methylxanthines and the planar aromatic molecules of the intercalating drugs: formation of caffeine-drug complexes in solution effectively lowers the concentration of the free drug and thereby reduces its pharmacological activity. The principle of selective entrapment of the intercalator by compounds like caffeine may be considered in designing strategies to modulate the activity of intercalating drugs in vivo, e.g., in lowering drug toxicity when inadvertently applied at too high doses.

Acridine Orange↗
PubMed1991

Caffeine reverses the cytotoxic and cell kinetic effects of Novantrone (mitoxantrone).

Caffeine is known to potentiate the cytotoxicity of a variety of DNA damaging agents presumably by reducing the ability of the cells to repair potentially lethal lesions. However, in the present study we observe that 5 mM caffeine reverses the cell kinetic and cytotoxic effects of the intercalating drug Novantrone (mitoxantrone) on L1210, HL-60 and CHO cells. Novantrone alone, at a concentration of 20-30 ng/ml, given to cultures for 1 h, inhibits cell growth by about 50% and causes cells to accumulate in S and G2 phase and to enter a higher DNA ploidy level. Treatment of these cell lines with 5 mM caffeine alone for 1 h has a minimal effect on cell proliferation; suppression of cell growth varies from 5 to 10%. Exposure of cells to Novantrone for 1 h in the presence of caffeine results in a significant reduction of the Novantrone effects; the cell growth rate is partially restored (e.g. caffeine reduces suppression of L1210 cell growth from 48 to 83% of control) and in each of the cell lines studied, the Novantrone-induced cell accumulation in S and G2 is abolished. Combined treatment with caffeine and Novantrone also increases the clonogenicity of CHO cells 8.5 times over that seen in cultures treated with Novantrone alone. In contrast to the combined treatment with caffeine + Novantrone, pretreatment of cells with caffeine provides no protection. Likewise, post-treatment with caffeine provides little reversal of growth inhibition and G2 cell accumulation, especially if the post-treatment is delayed in time. The present data, in conjunction with evidence in the literature that caffeine protects cells against the cytotoxic effects of doxorubicin, suggest that caffeine may play a more general role in protecting cells against planar aromatic molecules such as intercalating agents.

Animals↗
PubMed1990

Follicular neoplasms of the thyroid in men older than 50 years of age. A DNA flow cytometric study.

The clinical behavior of follicular neoplasms of the thyroid in elderly men can be difficult to predict on histologic grounds alone. To assess the usefulness of DNA flow cytometry in predicting the metastatic potential of these tumors, the authors studied 44 primary and metastatic follicular neoplasms of the thyroid by DNA flow cytometry of paraffin-embedded tissue. The neoplasms were obtained from 44 men ranging in age from 50 to 79 years (mean, 60). There were 29 follicular adenomas, 11 primary follicular carcinomas (neoplasms with capsular and/or vascular invasion), and 4 metastatic follicular carcinomas. Follow-up information was available on 40 of the 44 patients. The mean follow-up was 114 months. Twenty-five of the 29 follicular adenomas had a diploid DNA content, 2 (7%) were tetraploid, and the DNA histograms on 2 were not interpretable. All patients with follicular adenomas had no evidence of disease (NED) at last follow-up. Eight of the 11 primary follicular carcinomas were diploid. Six of these patients had NED, one died with carcinoma at 82 months, and no follow-up was available on one. Three (27%) of the primary follicular carcinomas were aneuploid or tetraploid. Two of these patients had NED, and the third died with carcinoma 84 months after diagnosis. Two of the four metastatic follicular carcinomas were diploid and two (50%) were aneuploid or tetraploid. One of the two patients with diploid metastatic follicular carcinomas died with carcinoma, as did one of the two patients with aneuploid metastatic follicular carcinomas. These results suggest the following: (1) follicular carcinomas are more likely to be aneuploid or tetraploid than are follicular adenomas; (2) follicular neoplasms without capsular or vascular invasion may include a small number of aneuploid or tetraploid tumors; and (3) DNA ploidy does not add to the prognostic value of histologic studies alone.

Adenocarcinoma↗
PubMed1990

Comparison of anatomical location of squamous cell carcinoma within the oral cavity and oropharynx with the incidence of in vitro hyperdiploidy.

The anatomical location of the squamous cell carcinoma (SCCA) within the oral cavity and oropharynx influenced the association of SCCA with the biomarker in vitro hyperdiploidy in human dermal fibroblast cultures (IVH). There was a strong association of IVH with the occurrence of SCCA in the anterior 2/3 of the tongue, floor of the mouth and lower alveolar ridge of the oral cavity and in the base of the tongue and pharyngeal wall of the oropharynx. There was a lower association of SCCA with IVH in the tonsillar region of the oropharynx. IVH showed no association with SCCA located in other anatomical parts of the oral region. The patient group whose diagnosis of SCCA in the anterior 2/3 of the tongue occurred prior to the age of 50 years were invariably IVH-, whereas those diagnosed after the age of 50 years were IVH+, providing evidence for heterogeneity. There was no such correlation of biomarker subgrouping with age of diagnosis demonstrated for SCCA at any other anatomical location within the oral cavity or oropharynx.

Adult↗
PubMed1990

Chordomas with malignant spindle cell components. A DNA flow cytometric and immunohistochemical study with histogenetic implications.

The authors studied four chordomas with malignant spindle cell components (SCs) and 12 conventional chordomas (CCs) by DNA flow cytometry using paraffin-embedded tissue. In addition, immunohistochemical stains for a variety of epithelial and mesenchymal markers were performed. The four SCs contained areas histologically identical to conventional chordomas, as well as a high-grade malignant spindle cell component. All four (100%) SCs had an aneuploid-multiploid DNA content. Of interest, the conventional chordoma areas in these tumors had DNA contents different from those containing the high-grade malignant spindle cells. In contrast, only three (27%) of the 11 conventional chordomas with analyzable histograms had an aneuploid-multiploid DNA content. Immunohistochemical studies performed on the four SCs showed the high-grade malignant spindle cells to stain strongly for vimentin and weakly for cytokeratin, S-100 protein, and epithelial membrane antigen (EMA), whereas the areas of conventional chordoma in these same neoplasms stained moderately for vimentin and S-100 protein, and strongly for cytokeratin and EMA. In two cases, the staining for EMA and cytokeratin highlighted a gradual transition between the areas of conventional chordoma and the spindle cell areas. The immunohistochemical staining pattern of the 12 conventional chordomas was similar to that seen in the conventional chordoma components of the four chordomas with malignant spindle cell components. These results suggest that: 1) aneuploidy is more common in SCs than in CCs, and 2) some SCs are multipotential neoplasms in which the neoplastic cells are capable of differentiation along both epithelial and mesenchymal pathways.

Adult↗
PubMed1989

Benign metastasizing giant cell tumors of bone. A DNA flow cytometric study.

Approximately 2% of histologically benign giant cell tumors (BGCT) of bone are complicated by lung metastases, which can progress despite their benign histologic appearance. Almost all BGCT studied by DNA flow cytometry (FCM) have been reported to be diploid. However, the very few cases with lung metastases previously analyzed were all aneuploid. To assess the usefulness of DNA FCM in predicting the metastatic potential of BGCT, seven metastasizing BGCT were studied by DNA FCM using paraffin-embedded tissue. Five were purely diploid, one was tetraploid, and one was aneuploid. The primary and the metastasis showed the same DNA distribution in all but the tetraploid case, in which the metastasis was purely diploid. A single patient, who was in the diploid group, had unresectable tumor in the lungs; she remains alive with stable disease at 30 months. The other six patients, who underwent complete resections of their lung metastases, are free of disease. These results suggest that DNA FCM is not a sensitive method for predicting the metastatic potential of BGCT since most metastasizing cases appear to be diploid.

Aneuploidy↗
PubMed1989

Decreased content of the 35 kDa cytoskeletal protein p35 in Friend erythroleukemia cells exposed to dimethyl sulfoxide and retinoic acid is associated with entrance into a quiescent substrate.

1. The effect of all-trans-retinoic acid (RA) on cell cycle kinetics, RNA content, and expression of the 35 kDa cytoskeletal protein p35 in exponentially-growing Friend erythroleukemia (FL) cells was compared with the prototypic differentiation-inducer dimethylsulfoxide (DMSO). 2. Two G1 phase populations of RA-treated FL cells were identified: one with an intermediate RNA content (T-cells) similar to G1 cells in near-plateau-phase control cultures and the other with a very low RNA content (Q-cells) similar to DMSO-differentiated cells; although quiescent, RA-treated cells remained undifferentiated as evidenced by the absence of late-stage markers of erythroid maturation. 3. Decreases in the cellular content of p35 occurred in both DMSO- and RA-treated FL cells, correlating with the onset of accumulation of cells into G1, and stabilized by 48 hr after initial exposure to either inducer. 4. Down-regulation in the cellular p35 content, thus, appears to be linked to entrance of FL cells into a quiescent substrate and independent of the subsequent capacity for erythroid differentiation.

Animals↗
PubMed1989

Growth of immortal simian virus 40 tsA-transformed human fibroblasts is temperature dependent.

Simian virus 40 (SV40)-mediated transformation of human fibroblasts offers an experimental system for studying both carcinogenesis and cellular aging, since such transformants show the typical features of altered cellular growth but still have a limited life span in culture and undergo senescence. We have previously demonstrated (D. S. Neufeld, S. Ripley, A. Henderson, and H. L. Ozer, Mol. Cell. Biol. 7:2794-2802, 1987) that transformants generated with origin-defective mutants of SV40 show an increased frequency of overcoming senescence and becoming immortal. To clarify further the role of large T antigen, we have generated immortalized transformants by using origin-defective mutants of SV40 encoding a heat-labile large T antigen (tsA58 transformants). At a temperature permissive for large-T-antigen function (35 degrees C), the cell line AR5 had properties resembling those of cell lines transformed with wild-type SV40. However, the AR5 cells were unable to proliferate or form colonies at temperatures restrictive for large-T-antigen function (39 degrees C), demonstrating a continuous need for large T antigen even in immortalized human fibroblasts. Such immortal temperature-dependent transformants should be useful cell lines for the identification of other cellular or viral gene products that induce cell proliferation in human cells.

Antigens, Polyomavirus Transforming↗
PubMed1989

The antitumor intercalating drug ditercalinium binds preferentially to RNA in Friend erythroleukemia cells.

Ditercalinium (DIT; NSC 335153), a 7H-pyridocarbazole dimer, was reported to be capable of binding with high affinity to DNA by bisintercalation. Both the cytostatic and cytotoxic effects of this drug have been attributed to its binding to DNA. DIT inhibits the growth and is cytotoxic to Friend erythroleukemia (FL) cells. When FL cells were treated with 0.5-2.5 microM DIT and then stained with acridine orange (AO), which differentially stains DNA and RNA, the green, orthochromatic fluorescence representing AO binding to DNA was unchanged, while the metachromatic red luminescence characteristic of AO binding to RNA was reduced by as much as 40% in 4 hr; the effect was DIT-concentration dependent. The reduction in RNA stainability by DIT in the absence of any significant decrease in RNA content, was also observed with another RNA-specific fluorochrome, pyronin Y (PY). These results indicate that in live cells DIT preferentially binds to RNA rather than DNA, preventing stainability of the former by the monointercalating dyes AO and PY. When FL cells were exposed to 10 microM DIT after being first permeabilized by ethanol, the subsequent stainability of DNA in these cells was reduced by up to 67% and RNA by up to 44%, indicating that under these conditions DIT binds to both DNA and RNA. This observation was confirmed by competition experiments between AO and DIT bound to DNA or RNA in permeabilized cells mixed with equivalent numbers of RNA-containing (DNase-treated) or DNA-containing (RNase-treated) cells, respectively. The mechanisms that protect DNA against binding by DIT in live cells are unknown but are lost in fixed cells and may be related to maintenance of cellular and/or nuclear membrane integrity. If the propensity for other intercalating drugs to bind to RNA in live cells is correlated with their antitumor activity as is DIT, the rationale for designing new drugs based solely on their affinity for DNA should be reevaluated.

Acridine Orange↗
PubMed1988

A transformation-associated 130-kD cell surface glycoprotein is growth controlled in normal human cells.

Two characteristics of cell surface molecules involved in the regulation of cell proliferation are altered expression in relation to growth phase in normal cells and overexpression in transformed cells. Here, we describe a similar pattern of expression for a 130-kD cell surface glycoprotein (gp 130) in human cells. Synthesis and cell surface expression of gp130 were greatly increased in both virally and chemically transformed fibroblasts, fibrosarcomas, a squamous cell carcinoma of the skin, and T cell leukemia lines. Furthermore, gp130 expression was induced in serum-starved fetal fibroblasts by serum stimulation, and in fresh T cells by various activating agents. Expression in response to serum stimulation was associated primarily with the transition from a quiescent state (G0) into the cell cycle (G1).

Carcinoma, Squamous Cell↗
PubMed1988

Staining with pyronin Y detects changes in conformation of RNA during mitosis and hyperthermia of CHO cells.

Cellular RNA in Chinese hamster ovary (CHO) cells synchronized in mitosis (M) or G2 phase, as well as in interphase cells subjected to hyperthermia (42 degrees C, 10 min), was stained with acridine orange (AO), ethidium bromide (EB), or pyronin Y (PY) and the resultant fluorescence was measured by flow cytometry. Total RNA content detected after staining with AO increased in M as compared to G2-phase cells, consistent with continued RNA synthesis during G2 phase. The content of double-stranded RNA, stained with EB (after DNase treatment), was also somewhat higher in M cells. In contrast, the stainability of RNA with PY decreased by 27% in M- compared to G2-phase cells. Furthermore, a decrease in stainability of RNA with PY was observed in G2 cells compared to cells in G1 phase. In separate experiments, RNA stainability with AO or EB was generally unaffected when interphase CHO cells were exposed to 42 degrees C for 10 min, though this same treatment resulted in a 26% decrease in RNA stainability with PY. The decreased PY stainability of cellular RNA in M or heat-treated cells was observed at a relatively narrow range of dye concentration (1.0-2.0 micrograms/ml). The observed hypochromicity of RNA coincides with dissociation of polyribosomes into single ribosomes known to occur during mitosis and following exposure to hyperthermia. It is presumed that the phenomenon involves selective denaturation and condensation of ribosomal (r) RNA by PY in single ribosomes which does not occur in polyribosomes. While the molecular mechanisms responsible for stabilization of rRNA in polyribosomes preventing its denaturation and condensation by PY are unknown, PY appears to be a sensitive probe that can be used to detect and study these changes in rRNA confirmation in situ.

Animals↗
PubMed1988

Interactions of antitumor drug ditercalinium with nucleic acids in solutions and in situ.

Ditercalinium (7-H-pyridocarbazole dimer), a prospective antitumor drug, is a bis-intercalator characterized by a very high affinity towards nucleic acids. Specificity of binding of this drug has been studied using spectroscopy and flow cytometry. The competition experiments between the drug and 4',6-diamidino-2-phenylindole.2HCl (DAPI) or acridine orange indicate that in solution the drug had higher affinity to DNA whereas in situ it binds preferentially to RNA. The results suggest that despite their high affinity towards DNA, the intracellular target of some intercalating drugs may be RNA.

Antineoplastic Agents↗
PubMed1988

Demonstration of altered cellular DNA content distribution in long-term colon epithelial cell lines with colon cancer genotypes.

During prolonged culture (7-40 passages assayed) DNA distribution was constant in IVT-negative lines with FPC genotype and in IVT-negative lines without any known colon cancer genotype, whereas the DNA histograms of the IVT-positive lines with HNPCC genotype showed a marked change. The DNA index (DI) of greater than 1 increased sixfold in the HNPCC-A (affected) line and threefold in the HNPCC-AR (at-risk) line due to an equal increase in DI of 2 and DI of greater than 2. It is proposed that there is a possible association between the HNPCC genotype, the presence of IVT, and the marked increase in both DI of 2 and DI of greater than 2 in DNA histograms, since neither the lines with normal nor those with FPC genotypes showed these changes. The biological significance of IVT might be due to its influence on the constancy of the distribution of cellular DNA content, leading to aneuploidy, which has been known to precede in vitro tumorigenic phenotypes.

Adolescent↗
PubMed1988

Unstainable DNA in cell nuclei. Comparison of ten different fluorochromes.

Ten fluorochromes with specificity for DNA were used to compare the stainability of nuclei of exponentially growing, nondifferentiated Friend leukemia (FL) cells with that of dimethylsulfoxide-induced, fully differentiated FL cell nuclei. Decreased accessibility of DNA to several dyes, particularly pronounced in the case of some intercalators, was observed in differentiated cells. Dye binding was also compared for both sets of nuclei following extraction of nuclear proteins, mostly histones, with 0.1-N HCl. Acid extraction of nuclear proteins increased the accessibility of DNA to varying degrees, depending upon the fluorochrome. In most cases, the differences in fluorescence between differentiated and nondifferentiated nuclei stained with most intercalating dyes was abolished by acid treatment. The results are discussed in terms of the mode of interaction between DNA and the various fluorochromes and the factors associated with chromatin structure, which may affect or be associated with different degrees of proliferative activity.

Cell Nucleus↗
PubMed1987

Effects of a new amsacrine derivative, N-5-dimethyl-9-(2-methoxy-4-methylsulfonylamino)phenylamino-4- acridinecarboxamide, on cultured mammalian cells.

The effects of N-5-dimethyl-9-(2-methoxy-4-methylsulfonylamino)-phenylamino-4- acridinecarboxamide (CI-921; NSC 343499), a lipophilic and water-soluble derivative of amsacrine (NSC 249992), on cell viability, growth, clonogenicity, and progression through the cell cycle were investigated in suspension cultures of Friend erythroleukemic cells and in in suspension cultures of Friend erythroleukemic cells and in adherent cultures of Chinese hamster ovary cells. CI-921 was less toxic toward stationary than toward exponentially growing Chinese hamster ovary cells; colony formation was inhibited by 50% following a 1-h pulse of 190 versus 80 nM CI-921, respectively. Cell viability was unaffected in Friend erythroleukemic cell cultures at concentrations up to 50 nM, although growth was inhibited by 50% following 24 h of continuous exposure to 9.5 nM or a 1 h pulse of 67.5 nM CI-921. Constant exposure of Friend erythroleukemic cells to 10 nM CI-921 slowed proliferation and resulted in prolongation of cell transit through late S and G2 phases. Higher drug concentrations (50 nM) caused a complete cessation of growth marked by greatly suppressed cell transit through S phase and an irreversible block in G2 phase, about 30 min prior to division. In such cases, unbalanced growth was observed with total RNA and protein content of drug-treated cells increasing by 74 and 34%, respectively. Pulse exposure of cells to CI-921 resulted in transient accumulations of cells in S and/or G2 phase depending upon dose. The cell cycle distribution of stationary cultures treated for 1 h with drug and replated at a low cell density were identical to that of controls. Binding of the drug affected the sensitivity of DNA in situ to acid denaturing conditions which provides additional evidence that CI-921 binds to DNA by intercalation.

Amsacrine↗
PubMed1987

Application of pyronin Y(G) in cytochemistry of nucleic acids.

Chinese hamster ovary (CHO) cells or isolated nuclei were stained with pyronin Y(PY) and analyzed by absorption or fluorescence microscopy, as well as by flow cytometry. Specificity of the staining reaction was assayed by testing sensitivity of the stainable material to RNase or DNase. The colored complexes detected by light absorption in fixed cells stained with PY are nonfluorescent and are most likely the products of condensation of single-stranded (ss) RNA by PY; the poly(rA) and poly(rA,rG) are the most sensitive to condensation. The products of PY interaction with double-stranded (ds) nucleic acids are fluorescent and can be detected in cells by cytofluorometry. PY used alone stains both DNA and RNA, and the staining capabilities of these nucleic acids vary depending upon the PY concentration at equilibrium; at a concentration above 330 microM, the RNA stainability decreases, perhaps due to its denaturation and condensation caused by the dye. In the presence of Hoechst 33342, PY can specifically stain RNA in fixed cells or isolated cell nuclei. Because only complexes of PY with ds RNA are fluorescent, this dye can be used as a probe of RNA conformation, e.g., to monitor denaturation of RNA in situ. The RNA stainability of mitotic cells is about 25% lower than that of cells in G2 phase, which indicates that during mitosis proportionately less cellular RNA is in the ds conformation. The advantages and limitations of the two cytochemical methods for DNA/RNA detection, one based on the use of Hoechst 33342 and PY, and another employing the metachromatic properties of acridine orange, are compared.

Animals↗