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F Liautaud-Roger

Publications and source records attributed to F Liautaud-Roger.

At least 19 recordsLinked to original sources
PubMed2000

Nuclear chromatin texture and sensitivity to DNase I in human leukaemic CEM cells incubated with nanomolar okadaic acid.

It is now known that the analysis of chromatin texture can be used in oncology as a sensitive detection method, either to define diagnostic classifications or to locate a lesion along a defined trend curve. However, the functional significance of these variations in textural features remains sometimes unclear. Several drugs have been shown to be able to modulate chromatin structure. Among them, the phosphatase inhibitor okadaic acid at low concentration can increase accessibility to DNA in chromatin of carcinoma cells. This paper demonstrates that short exposures (0-3 h) to a 10-nM dose of okadaic acid induced an increased sensitivity to DNase I digestion in human CEM leukaemic cell nuclei and that this sensitization was associated to variations of nuclear texture characteristics, as evaluated by image cytometry. CEM cells treated with okadaic acid for 0-3h displayed changes in chromatin supraorganization with a more homogeneous and fine chromatin texture, as compared to control cells. This suggests that the appearance of an open configuration of chromatin structure as evaluated by biochemical methods corresponds to a more decondensed texture of nuclei measured by image cytometry. Longer exposures (6-24h) of CEM cells to 10 nM okadaic acid lead to apoptosis. As reported previously for camptothecin-treated HL60 cells, okadaic acid-treated CEM cells display biphasic nuclear chromatin texture changes, i.e. a decondensation phase followed by the appearance of typical apoptotic cells with a smaller nuclear area and a highly condensed chromatin. Finally, using the multidrug-resistant CEM-VLB cell line, it was confirmed that these multidrug-resistant cells also display cross-resistance to okadaic acid, as this compound was unable to induce either increased DNase I sensitivity, apoptosis, or altered nuclear texture in this particular cell line.

Apoptosis↗
PubMed1999

Textural analysis of nuclear mitotic apparatus antigen (NuMA) spatial distribution in interphase nuclei from human drug-resistant CEM lymphoblasts.

In tumour cell lines, the resistance of cancer cells to a variety of structurally unrelated chemotherapeutic drugs is termed multidrug-resistance or MDR. We reported previously [6] that MDR leukemic cells displayed nuclear texture changes, as assessed by image cytometry. The nature of these changes remained uncertain but they could be associated with alterations of the nuclear matrix which could serve an important role in DNA organization and chromatin structure. Therefore, we have compared the textural features observed in G0/G1 nuclei from human leukemic CEM cells and their MDR variant CEM-VLB, after staining of either DNA by Feulgen method or nuclear matrix by immunodetection of NuMA antigen on DNase treated samples. Chromatin or NuMA distributions within the nucleus were evaluated by image cytometry. Changes in textural parameters indicate that modifications of NuMA distribution observed in MDR cells are parallel to those observed at the whole chromatin level (i.e., a more decondensed and coarse texture with increase of Energy and Long-run sections and decrease of Contrast and Short-run sections). Moreover, Optical Densities measurements indicate that MDR cells seem to contain less NuMA, a datum confirmed by immunoblotting of nuclear proteins. In conclusion, chromatin changes observed by image cytometry in drug-resistant human leukemic CEM cells appear associated with modifications of the nuclear matrix structure.

Antigens, Nuclear↗
PubMed1998

Enhancement of all-trans-retinoic acid efficiency in granulocytic differentiation of HL-60 cells by incorporation into low density lipoprotein.

All-trans-retinoic acid (ATRA) has been proven to lead to complete remission of acute promyelocytic leukemia by inducing differentiation into granulocytes except when an acquired resistance occurred. High levels of low density lipoprotein (LDL) receptor in cancer cells suggested the use of ATRA incorporated into LDL. 50% of HL-60 cell differentiation were obtained with 5 nmoles/l of ATRA-LDL compared to 150 moles/l of ATRA. Maximal differentiation (80%) was reached at 25 nmoles/l and 1,000 nmoles/l respectively. This higher efficiency suggests the involvement of LDL receptor in ATRA-LDL internalization and/or the protection of the drug, from eventual catabolism, by LDL particles.

Binding, Competitive↗
PubMed1997

P53 protein expression in human multidrug-resistant CEM lymphoblasts.

A role for p53 in the regulation of multidrug-resistance (MDR) has been postulated as wild-type p53 suppresses and mutant p53 specifically activates the mdr1 promoter. Moreover, changes in p53 expression and/or functions could be implicated in drug resistance. As the parental lymphoblastic CCRF-CEM cell line has been described as expressing a mutated form of p53, we have examined p53 and mdm2 protein levels in the human multidrug-resistant CEM-VLB cell line variant. These drug-resistant CEM-VLB cells, which have increased expressions of mdr1 and P-glycoprotein, displayed p53 and mdm2 protein expressions similar to those observed in their sensitive CCRF-CEM counterparts. Treatment of these drug-resistant cells with non-toxic doses of the resistance-inducing drug vinblastin induced a strong increase in p53 protein and mRNA but was ineffective on mdm2 protein expression, or mdr1 mRNA expression. These data indicate that mutant p53 protein was not overexpressed in these MDR cells. This overexpression could be induced by microtubule-active drug treatment, but, as previously observed in other sensitive cell lines, mutant p53 from these MDR cells was unable to positively regulate mdm2 gene product expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Image cytometry of early nuclear events during apoptosis induced by camptothecin in HL-60 leukemic cells.

The nuclear morphological alterations occurring during apoptosis induced in human HL-60 cells by camptothecin were analyzed quantitatively by image cytometry. Two separate phases were identified during the apoptotic process. The first phase, observed between 0-2 h of incubation, consisted in the appearance of cells with an apparently decondensed chromatin. This phenomenon was blocked by the inhibitors of DNA fragmentation, TLCK and H7. In contrast, staurosporine and cytochalasin B, which inhibit apoptosis without any effect on DNA fragmentation in this system, did not prevent this morphological change. The second phase, observed after 3 h of culture, corresponded to the appearance of cells with very homogeneous and condensed chromatin. This phenomenon correlated with the detection of typical apoptotic cells with fragmented nuclei and was inhibited by all drugs (TLCK, H7, staurosporine, and cytochalasin B). These observations suggest that image cytometry allows the detection of subvisual microscopic events within the first hour after the induction of an apoptotic process and that the dissection of this process into several different phases might be associated with DNA fragmentation.

Apoptosis↗
PubMed1996

Analysis of DNA content in multidrug-resistant cells by image and flow cytometry.

Nuclear DNA content was assessed in multidrug-resistant (MDR) cells by image and flow cytometry. Two human MDR cell lines (K562-Dox and CEM-VLB) obtained by in vitro drug selection and overexpressing mdr1 gene were compared to their respective sensitive counterparts (K562 and CCRF-CEM) and to the MDR hamster LR73-R cell line obtained by transfection of mouse mdr1 cDNA. Both cell lines obtained by selection displayed a decreased DNA content, as measured by image cytometry after Feulgen staining, or by flow cytometry after staining with propidium iodide, ethidium bromide, or Hoechst 33342. This decrease was not accompanied by changes in cell cycle phase distribution of cells. Moreover, image cytometry of cells stained after various hydrolysis times in 5 M HCl indicated that MDR cells displayed the same hydrolysis kinetics and sensitivity as drug-sensitive cells with a well-preserved stoichiometry of the Feulgen reaction. LR73-R cells transfected with mdr1 cDNA exhibited only a very limited change in propidium iodide staining as compared with sensitive LR73 cells, suggesting that mdr1 gene overexpression alone could not account for the alterations in DNA content observed in the selected MDR cells.

Animals↗
PubMed1996

Ultrastructural changes related to multidrug resistance in CEM cells: role of cytoplasmic vesicles in drug exclusion.

The multidrug resistance phenotype is found to be frequently associated with the overexpression of proteins which lead to a decrease of drug accumulation within human tumor cells. A 170 kDa membrane glycoprotein which is related to the overexpression of the mdr1 gene is inserted in the plasma membrane and pumps the cytotoxic drugs out of the cells. The aim of this work was to study the morphological modifications of resistant CEM/VLB 100 cells relative to their parental drug-sensitive ones and the detection of the ultrastructural localization of P-glycoprotein at the cytoplasmic level. Using a scanning electron microscope, CEM resistant cells showed wide smooth protrusions while CEM sensitive cells showed microvilli and fine folds. With transmission electron microscopy, an enhanced secretory system was observed in CEM resistant cells: both electron transparent and electron opaque vesicles were associated with the Golgi system, revealed by wheat germ agglutinin-colloidal gold labelling. These vesicles were the binding site of C 219 and MRK 16 antimembrane glycoprotein antibodies, and some of them were determined to belong to the lysosomal system after PTA staining. These vesicles may be an additional way to decrease the cellular uptake of drugs in multidrug resistant cells. Moreover, some nuclear and nucleolar modifications were also observed. These observations show that MDR has wide morphological features which concern several organelles.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Nuclear DNA content and chromatin texture in multidrug-resistant human leukemic cell lines.

Nuclear morphological alterations associated with multidrug resistance (MDR) were evaluated by image cytometry in various human leukemic cell sub-lines: 3 cell lines with P-gp-mediated resistance (CEM-VLB, HL60/Vinc, K562-Dox), the non-Pgp-mediated MDR HL60/AR leukemic cell line with over-expression of MRP, and the at-MDR CEM-VMI leukemic cell line with alteration of topoisomerase II. All these MDR cell sub-lines were obtained by drug selection and were compared with their sensitive counterparts and with the hamster LR73-R cell line obtained by transfection of mouse mdrl cDNA. All MDR cell sub-lines obtained by drug selection displayed decreased DNA Feulgen stainability as compared with their respective sensitive parental cell line, a phenomenon not observed in the transfected LR73-R cells. Nuclear texture analysis on G0/G1-selected cell nuclei revealed 2 types of textural phenotype. The first phenotype was characterized by chromatin decondensation with small but compact chromatin clumps, and was observed in drug-selected P-gp-mediated MDR cells (CEM-VLB, HL60-Vinc, K562-Dox) and in the non-P-gp-mediated MDR HL60/AR cell line. The second phenotype was characterized by a condensed and homogeneous chromatin pattern, and was observed in the at-MDR CEM-VMI cell line. LR73-R cells transfected with mdrl cDNA did not display any significant changes in textural phenotype as compared with sensitive LR73 cells, suggesting that P-gp over-expression alone cannot account for the cytological modifications observed in MDR cells. These data suggest that multidrug resistance could be associated with specific nuclear morphological changes which appeared to be a consequence of alterations occurring during selection by cytotoxic drugs rather than of P-gp over-expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Nucleus image analysis as a possible prognostic tool in grading breast cancer.

The WHO grading system for breast cancer is based on the subjective, poorly reproducible evaluation of two cytological criteria (Mitotic Activity: MA and Nuclear Pleiomorphism: NP) and one histological criterion (Tubular Differentiation: TD). In order to improve the reproducibility of the assessment of tumour differentiation, we have looked for nuclear cytophotometric parameters (densitometry, geometry and texture) that could be measured objectively on smears stained by the Feulgen method. Tumour cell populations from 36 breast cancers were investigated by nuclear image analysis according to NP scores, MA scores, TD scores (ie for each variable, three categories), WHO total scores (3 to 9 or 7 categories) and WHO grades (grade I: 13 patients, whereas 13 and 10 for grade II and III respectively). Discrimination between each score or grade could be displayed by the average profiles of the nuclear cytophotometric parameters provided by multivariate analysis. Discrimination between TD scores was based on two parameters of nuclear texture. All these data suggest that WHO grading could be obtained in an objective manner by nuclear image analysis.

Adult↗
PubMed1992

Thyroid neoplasms. Can we do any better with quantitative cytology?

The differential diagnosis of thyroid neoplasms by routine cytology presents major difficulties. We therefore looked for measurable nuclear parameters that could be generated from Feulgen-stained smears obtained by fine needle aspiration biopsy (FNAB). These parameters would then be used to differentiate between benign and malignant lesions. Seventy-six patients whose cold thyroid nodule was surgically excised after FNAB and examined by a pathologist were used in this study: 56 benign, 18 malignant and 2 atypical adenomas. A set of 3,662 cells from the 33 benign cases was compared with the set of 1,712 cells from the 11 malignant nodules. Discrimination between the two populations was based on four nuclear features ranked according to their discriminating power. The first ranked was a textural parameter, followed by a densitometric and finally two other textural parameters. The rate of nuclei that could be regarded as benign was computed for each case using the ranked parameters. The average rate for the 33 benign cases was 85% (50.2 = 100%, set at the 95% confidence interval). In a prospective study of the 32 remaining patients, sensitivity and specificity were, respectively, 92% and 88%, which were higher than those obtained by conventional cytology.

Adenoma↗
PubMed1992

Can chromatin texture predict structural karyotypic changes in diploid cells from thyroid cold nodules?

To assess the effect of a single chromosomal translocation on the nuclear phenotype of human cells, seven diploid adenomas and five diploid carcinomas of the thyroid gland were studied using quantitative nuclear morphometry. Four adenomas and three carcinomas were cytogenetically normal, whereas three adenomas and two carcinomas had a unique chromosomal translocation. A densitometric parameter discriminated adenomas from carcinomas (skewness of the optical density histogram, SODH), and tumours with and without chromosomal translocation (standard deviation of the optical density, SDODH). These results demonstrate that single chromosomal structural rearrangements produce quantifiable alterations of nuclear organisation, but that other nuclear features which do not express an aneuploid DNA content or an abnormal karyotype differentially characterise benign and malignant conditions.

Adenoma↗
PubMed1990

Chromosomal changes in thyroid tumors. Relation with DNA content, karyotypic features, and clinical data.

A cytogenetic study was performed in 63 thyroid tumors after a monolayer short-term culture. Clonal chromosomal changes were found in 47% of carcinomas and 31% of adenomas. Chromosome 7 was altered in 40% of cytogenetically abnormal tumors. The modal DNA index measured in 26 tumors was consistent with the chromosomal mode in 88% of cases. A quantitative morphometric analysis of nuclear features differentiated between diploid thyroid adenomas with or without a single translocation, which suggests that they have different biological properties. Clonal chromosomal changes were observed in 78% of carcinomas with an aggressive behavior, but only 28% of those had no risk factors. The two patients who died early had abnormalities of chromosome 7.

Adenoma↗
PubMed1990

Discriminating between protective and enhancing HIV antibodies.

Most attempts to produce a vaccine against HIV-1 infection are utilizing envelope protein components. Hypothetically such vaccine candidates could stimulate production of antibodies that enhance HIV-1 infection via the macrophage route of entry and, consequently, cannot be detected in the conventional neutralization assay. To study this hypothesis we report an assay designed to evaluate the protective/enhancing activity of serum from seropositive immunized or infected individuals. Highly purified activated FcR-bearing monocytes-macrophages were infected with HIV-1 in the presence of the sera, then washed and cocultured with activated peripheral blood mononuclear cells (PBMC) from a normal donor. Productive viral infection, as evaluated by p24 antigen semiquantitative assay in the culture supernatants, allow evaluation of protective/enhancing activity of the sera. The data clearly show that protective rather than enhancing activity is present in the serum of env protein-immunized individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Tetraploid cycle in ageing solid tumours.

When the mouse mammary adenocarcinoma 755 (Ca-755) reaches the plateau phase of growth, non-cycling cells with a G2-DNA content can be observed. They may belong to the diploid cell cycle but they could also be blocked in G0 or G1 of a tetraploid cycle. This hypothesis was tested in three ways: (1) non-cycling G2 nuclei were stained with a combination of Feulgen and naphthol yellow which revealed two populations, one with a low protein content and the other with a high protein content--the latter may represent nuclei ready to begin a new phase of DNA synthesis; (2) Feulgen staining and autoradiography were performed after tritiated thymidine had been administered to mice continuously: this showed that there were cells synthesizing DNA with a DNA index above 2; and (3) cells having 80 chromosomes, corresponding to the tetraploid cycle, were found almost exclusively in the plateau phase tumours. On the other hand, the use of texture and DNA parameters of the Feulgen stained nuclei showed that they were concentrated in a diploid cycle for tumours in the exponential phase of growth and were divided between a diploid and tetraploid cycle for 'plateau' cells. Neither the cause for, nor the role played by, polyploid cells is known.

Animals↗
PubMed1987

[Serum enzymes and triglycerides in mice with a mammary tumor (Ca-755 adenocarcinoma)].

Investigations on mice inoculated with Ca-755 mammary adenocarcinoma have shown that the levels of serum LDH (especially isozymes resulting from the B sub-unit), TGO and TG are higher than those found in normal mice, while PAL (only bone isozyme) and TGP are lower. Comparisons were made with tumour age (exponential and plateau-growth phases), which appeared to be important for LDH and PAL bone isozyme, since LDH increased and PAL decreased with increasing age of the tumour. For the PAL and TG alterations, there could be assumed an effect of cachectin (TNF: tumour necrosis factor).

Adenocarcinoma↗
PubMed1983

Accumulation of non-cycling cells with a G2-DNA content in ageing solid tumours. Study of the Ca 755 mammary adenocarcinoma of mice.

Mouse mammary adenocarcinoma Ca 755 was studied at two times in its growth: the exponential (8 days) and plateau phase (20 days). Cycling cells were labelled with [3H]thymidine injections at 4-hr intervals over 72-hr periods, i.e. three to five times longer than the generation times for the twentieth day and eighth day tumour cells respectively. By autoradiography, the increase of non-cycling cells in ageing tumours was confirmed. By single cell cytophotometry used after Feulgen staining it has been shown that the cells with a high DNA content (especially a G2-DNA amount) were in a higher proportion in the twentieth day tumours than in their eighth day counterparts. Combined cytophotometric and autoradiographic procedures have shown that nearly all cells with a G2-DNA content entered a non-cycling state in ageing tumours.

Adenocarcinoma↗
PubMed1979

Simultaneous microscopic and biochemical findings in breast carcinoma. Preliminary results.

Intratumoral protein and glucose phosphate isomerase (GPI) content as well as median nuclear DNA amount were determined in breast carcinoma that could be classified by Bloom's grading. These data were analyzed in comparison with TNM classification. Higher protein contents have been displayed in T2 or N+ breast cancers than in T1 or N- tumors. Bloom's grading is strongly correlated to median nuclear DNA content and to some extent with protein and GPI amount. With these results, we have to think about the value of prognostic cytologic criteria. The relationship between intratumoral protein content and prognostic clinical or histological data requires our attention. This would seem to dictate a need for caution in expressing the results of some variables in function of protein content.

Adult↗