Biomedical subjects

A Desplaces

Publications and source records attributed to A Desplaces.

At least 19 recordsLinked to original sources

PubMed1997

Characterization of acidic vesicles in multidrug-resistant and sensitive cancer cells by acridine orange staining and confocal microspectrofluorometry.

To study the pH gradient status through membranes of acidic vesicles, either in sensitive or in multidrug-resistant living cancer cells, we monitored the fluorescence-emission spectra of acridine orange. Successive stainings with a pH-sensitive dye and AO showed that low-pH organelles were stained red by AO. In these compartments, high AO concentrations are driven by the pH gradient through membrane vesicles. The resulting rise in the dye's oligomeric/monomeric ratio induced an increase in the red/green (655-nm/530-nm) emission intensity ratio. Therefore, the accumulation of AO in acidic organelles was appraised by determination of the contribution of the red emission intensity (R%) in each emission spectrum, using laser scanning confocal microspectrofluorometry. In vesicles of multidrug-resistant K562-R cells, R% is significantly higher (72 +/- 10%) than the value (48 +/- 8%) from K562-sensitive cells (p < 0.001). This result is interpreted as a more important accumulation of AO in acidic cytoplasmic structures of resistant cells, which induces a shift from AO monomers (green emission) to self-associated structures (red emission). Equilibration of the pH gradient through acidic organelles was performed by addition of weak bases and carboxylic ionophores. Ammonium chloride (0.1 mM), methylamine (0.1 mM), monensine (10 microM), or nigericine (0.3 microM) all suppressed the initial difference of local AO accumulation between both cell lines. These agents decreased the red emission intensity for the resistant cell line but not for the sensitive one. The same effects were induced by 50 microM verapamil, a pleiotropic drug-resistance modulator. Our data allow the hypothesis of a higher pH gradient through membranes of acidic organelles, which would be a potential mechanism of multidrug resistance via the sequestration of weak bases inside these organelles.

Acridine Orange↗

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↗

PubMed1994

[The metastatic process].

All the malignant tumors possess the same characteristic to form distant secondary tumors or metastasis. The acquisition of the metastatic potential takes place in random accumulation of different genetic and cellular changes. Their combination allows one or several tumor cells to achieve the whole metastatic process. The metastatic process involves numerous interactions between the tumor cells and the host cells of the tumor cells and the extracellular matrix. The attachment of the metastatic cells to the extracellular matrix specific glycoproteins involves cell surface receptors as integrins, sialyled residues or CD44. On the other hand, other adhesive molecules (Cadherins) display inhibitory action on the metastatic process. The enzymatic lysis is carried out by glycolytic enzymes and proteases: metalloproteases (inhibitors TIMP1 et TIMP2), serine proteases (tPA, uPA-inhibitors: PAI1 and PAI2). Cathepsin D or Heparanases. Several enzymes may be necessary for the degradation of the basal membrane. The crossing of both basal membrane and stroma can be made on account of the cell motility. Some factors can modify this property as AMF (Autocrin Motility Factor) or ATX (Autotoxin) but the molecular mechanisms involved in the migration are not yet completely understood. The last stage is relative to the cells proliferation in the site organ; it depends on autocrine (CSF1, IL2, Bombesine...) or some paracrine growth factors. However, the formation of metastasis is possible only in the site organ attaching the cells.

Animals↗

PubMed1994

[Quantitative cytological study of the activity of a new resistance modulator, S 9788, on human leukemic cells using multiparametric image analysis].

The triazinoaminopiperidine derivative S 9788 is a new multidrug resistance modulator. The modulating activity of S 9788, comparatively to those of verapamil and the combination of S 9788 and verapamil, was demonstrated on the human leukemic T cell line CCRF-CEM resistant (about 6000 fold) to vinblastine using Microculture Tetrazolium Assay. S 9788 at 5 microM, strongly potentialized the cytotoxic activity of vinblastine but the reversion of resistance remained partial. Verapamil and the combination S 9788-verapamil, tested at equimolar concentrations, were respectively 1000 and two times less active than S 9788 alone. The impact of S 9788, verapamil and their combination on the cytological modifications bound to vinblastine resistance of CEM cells was evaluated by multiparametric quantitative cytological analysis (21 nuclear parameters measured) using a SAMBA 2005 cell image processor. Treatments with the different modulators, in absence or in presence of vinblastine, had no significant effects on the morphology of sensitive CEM cells. On vinblastine resistant CEM cells, S 9788 and the combination S 9788-verapamil induced significant cytological modifications. These modifications were characterized by a partial reversion of some parameters (more specifically nuclear texture parameters) to values close to those observed in parental sensitive cells and permitted an automatic classification of these treated resistant cells in cells of "sensitive" type with a percentage superior to 50%. In conclusion, the reversion of resistance induced by S 9788 on CEM cells resistant to vinblastine does not fit only with a biological phenomenon like the efflux of cytotoxic agents but is associated with a set of cellular alterations involved in multidrug resistance.

Animals↗

PubMed1993

[Study of erythroid differentiation of K 562 cells resistant to adriamycin].

The induction of differentiation is at present one of the most promising pathway used in the field of cancer chemotherapy. As part of this research, the study of the human K562 erythroleukemic cells differentiation has shown that these cells are potent to synthesize hemoglobin when treated by 40 nmoles/l of adriamycin, 30 nmoles/l of aclacinomycin or 3.10(4) nmoles/l of hemin. This functional differentiation is accompanied by some changes in three membrane antigens expression: GPA, CD15 antigen and TfR. To complete these result, we have studied the differentiation of resistant K562 cells to adriamycin by these three inducers. Our results suggest that this cell population is able to synthesize hemoglobin after its exposition to 2.10(3) nmoles/l of adriamycin, 100 nmoles/l of aclacinomycin or 7, 5.10(4) nmoles/l of hemin. In contrary to aclacinomycin and adriamycin, hemin did not affect the three markers expression. On the other hand, only the induction by adriamycin causes membrane phenotypical changes which are erythroid differentiation specific.

Aclarubicin↗

PubMed1993

Exposure of C3H/Bi female mice with mammary carcinoma to pulsed magnetic fields.

Pulsed magnetic fields (PMF) have already proved to have a certain influence not only on leucocytes in vitro but also on thymocytes in vivo. C3H/Bi tumoral female mice were either exposed to 12 Hz or 460 Hz, and to 6, 9 or 20 mT PMF just two weeks after the tumors had appeared and this until the moment they died. Actually, all the survival times as well as the average weights of spleens lungs, and tumors were then taken into account at the very death of the mice. In a general way there happened to be no difference in spite of the different frequencies used and the rates of lungs with metastases were not at all influenced by the exposure itself. However a 3-hour-exposure once a week could increase the mean survival times whereas a 15-minute-exposure to a 6 mT PMF twice a week gave lighter spleens than those of the controls and an exposure either to 9 mT or to 20 mT gave heavier tumors in general.

Animals↗

PubMed1993

Quantitative morphological assessment of erythroblastic differentiation induced, in vitro, in human K562 leukemic cells.

K562 human leukemia cell line undergoes in vitro terminal differentiation towards the erythroid pathway following treatments with appropriate chemical agents including aclacinomycin, fagaronine and hemin. These three drugs induced a different expression of phenotypic and functional characters associated with differentiation. The morphological characteristics of the differentiation sequences elicited by these agents were evaluated by image analysis using a SAMBA 200 cell image processor. Multivariate statistical analyses of morphological data revealed that only aclacinomycin was able to induce significant modifications of the morphological parameters similar to those observed during the maturation of normal bone-marrow erythroblastic cells. These data correlate with the higher inductive potency of aclacinomycin as compared to hemin or fagaronine and suggest that quantitative cytology may be a useful adjunct to conventional tests for the selection of new drugs with differentiating potential.

Aclarubicin↗

PubMed1992

Studies on the susceptibility to NK-mediated lysis and the simultaneous expression of various surface molecules in anthracyclin-treated K562 cells and in four K562 cell clones.

Target molecules for NK cells are unknown. Numerous studies have proposed putative target molecules, but have examined their role in the modulation of sensitivity to NK-mediated lysis one independently of each other. We examined the simultaneous expression of various surface molecules and the susceptibility of K562 cells to NK attack. We have previously shown that adriamycin (40 nM) and aclacinomycin (15 nM) can induce, in vitro, an increase of glycophorin A (GPA) on K562 cells, a modulation of transferrin receptor (TfR) and CD15 antigen expression and a significant resistance of cells to NK-mediated lysis. In the present work, Fc gamma receptor II (CD32) expression at the K562 cell membrane was clearly decreased after aclacinomycin-treatment but was unaltered by adriamycin-treatment. Four K562 cell clones were studied. Two clones (F and G) expressed a higher level of CD32 at the membrane (62% and 70% of erythrocyte antibody (EA) rosettes respectively) and two clones (9 and 19) expressed lower a level (18% and 7% EA rosettes respectively) than the original population (43%). The sensitivity to lysis by NK cells was increased in clones F, G and 9 but decreased in clone 19 (without alteration in the binding capacity). Relationships between the sensitivity to NK attack and the levels of simultaneous expression of CD32, TfR, CD15, glycophorin A (GPA) and MHC class I monomorphic antigens were studied. In addition, the presence at the membrane of some cellular adhesion molecules (CD54, CD58, CD29, CD18, CD56) was examined in anthracyclin-treated cells and in the four clones. The difference in the sensitivity of target cells to NK attack is not strictly related to variation of one or other of these molecules. Our previous and present data suggest that the resistance of K562 cells to NK cells may correlate with the level of erythroid maturation at the cell membrane, involving simultaneous variations in expression of several molecules such as a decrease of TfR, CD15 and CD32 and an increase of GPA.

Aclarubicin↗

PubMed1991

Relationship between cathepsin D, urokinase, and plasminogen activator inhibitors in malignant vs benign breast tumours.

The concentrations of cathepsin D (Cath D), urokinase (uPA) and two plasminogen activator inhibitors (PAI-1 and PAI-2) were analysed in the cytosols of 130 human mammary tumours (43 benign tumours and 87 primary and unilateral breast carcinomas). uPA, PAI-1 and PAI-2 levels were measured by antigenic immunoassays and Cath D by immunoradiometric assay. The median levels of the four parameters were significantly higher in the malignant tumours than in the benign ones. Cath D and uPA increases were 4-fold and 5-fold respectively. PAI-1 and PAI-2 increases were much more important, 74-fold and 29-fold respectively. In malignant tumours, median levels of Cath D and uPA did not vary according to classical prognostic factors (histologic grade, presence or absence of axillary lymph nodes, steroid receptors, UICC stage, tumour size, age, and menopausal status). However, PAI-1 decreased in ER+ and PR+ tumours and PAI-2 increased in menopausal women's tumours. When Cath D, uPA, PAI-1 and PAI-2 levels in malignant tumours were compared, positive correlations were found for all combinations. The implication of plasminogen activator inhibitors in the phenomenon was surprising and merits further investigation using tools other than global antigen measurements in tumours.

Breast Diseases↗

PubMed1990

Flow cytometric analysis of DNA content and keratins by using CK7, CK8, CK18, CK19, and KL1 monoclonal antibodies in benign and malignant human breast tumors.

We have used a double-labelling flow cytometry analysis of keratin (CK) and DNA in breast cancer. Five monoclonal anti-keratin antibodies were tested: KL1 recognizing Mr 55,000-57,000 keratins, and "anti-glandular epithelia," LE41, RGE-53, and LP2K specific for CK n. 7, 8, 18, and 19 of Moll's classification, respectively. Flow cytometric (DNA-CK) analysis was performed on 10 benign and 19 malignant human breast tumors. All the benign tumors were diploid and 63% of the malignant tumors were aneuploid. This technique permits the analysis of DNA in the epithelial fraction alone. In aneuploid tumors, gating the DNA-keratin-positive population allowed accurate DNA analysis without interference due to debris background and non-epithelial cells. Moreover, double-labelling using the CK19 antibody gave a better identification of near-diploid tumors. An enhancement of keratin expression in malignant tumors was observed with CK 19 (P less than 0.001), KL1 (P less than 0.01), CK 8 (P less than 0.05), and CK18 (n.s.) compared to benign tumors. The comparison of keratin expression in aneuploid and diploid malignant tumors revealed reduced CK8, CK18, and CK19 in the former.

Antibodies, Monoclonal↗

PubMed1989

Cathepsin D: an independent prognostic factor for metastasis of breast cancer.

122 patients with primary breast cancer were followed-up for a median of 4.6 years after surgery. The concentration of cathepsin D in tumour cytosol was strongly related to both metastasis-free survival and disease-free survival and was independent of nine conventional prognostic indices. Cathepsin D assay may prove particularly useful in identifying women who, though without lymph node involvement at presentation, are at high risk of metastatic disease.

Adult↗

PubMed1989

Quantitative morphological analysis of adriamycin-resistant human K562 leukemic cells.

The morphological changes associated with Adriamycin resistance in a human leukemic cell line have been investigated by image analysis. An Adriamycin-resistant subline of the human erythroleukemic K562 cell line has been established. Three sets of cells have been analysed: sensitive cells, resistant cells cultured in the continuous presence of Adriamycin, and resistant cells cultured without the drug. Image analysis shows that Adriamycin-resistant K562 cells display significant morphological changes as compared with sensitive cells, at both the nuclear and cytoplasmic levels. These changes make it possible to separate sensitive and resistant cells automatically and with a classification accuracy of 76% and only four cytological parameters. Image analysis may therefore offer an interesting tool for studying drug resistance in leukemic cells, from both an experimental and a clinical point of view.

Cell Line↗

PubMed1989

Comparative effects of fagaronine, adriamycin and aclacinomycin on K562 cell sensitivity to natural-killer-mediated lysis. Lack of agreement between alteration of transferrin receptor and CD15 antigen expressions and induction of resistance to natural killer.

Little is known about membrane target antigens for natural killer (NK) cells. Transferrin receptor and CD15 antigen might be two of these target structures. A novel antileukemic alkaloid, fagaronine, is able to induce hemoglobin synthesis in the K562 cell line. Numerous reports suggest relations between the expression of natural killer target structures and the differentiation stage of malignant cells. Effects of fagaronine on the expression of glycophorin A, transferrin receptor and CD15 antigen and susceptibility to NK-mediated lysis have been investigated in K562 cells and compared to those of two anthracyclines (Adriamycin and aclacinomycin A) known to be erythroid-differentiation inducers. When comparing the balance of differentiating effect and toxicity, the dose and time-dependent effects of the drugs, fagaronine and aclacinomycin, are equivalent on K562 cells. In experimental conditions where fagaronine (3500 nM), Adriamycin (40 nM) and aclacinomycin (15 nM) recruit the same percentage of hemoglobin-containing cells (40%-50%), glycophorin A expression increases and transferrin receptor expression decreases. Only Adriamycin treatment decreases CD15 antigen expression. In addition, Adriamycin and aclacinomycin, but not fagaronine, induce resistance to NK-mediated lysis. These data suggest that (a) it is unlikely that CD15 antigen and transferrin receptor, separately considered, can be unique target structures for NK cells; and (b) fagaronine is a potent erythroid inducer which, in our system, has similar effects to aclacinomycin without induced resistance to NK attack.

Aclarubicin↗

PubMed1989

Quantitative morphological aspects of granulocytic differentiation induced in HL-60 cells by dimethylsulfoxide and retinoic acid.

HL-60 cells differentiate to mature granulocytes when cultured with DMSO or retinoic acid. These two drugs can induce different expression of phenotypic or functional properties in these cells. The morphological characteristics of the differentiation sequences elicited by these two drugs have been therefore evaluated by a quantitative cytological analysis technique using a SAMBA 200 cell image processor. The maturation sequences induced by DMSO or retinoic acid differed mainly in nuclear geometry and cytoplasmic granules expression. Multivariate statistical analyses of data reveal that DMSO and retinoic acid elicited granulocytic maturation through two separate morphological pathways which can be individualized as early as 24 hr after differentiation induction. Image processing may therefore offer an interesting tool for studying new drugs with differentiation potential in chemotherapy.

Analysis of Variance↗

PubMed1989

Cytokeratin analysis of breast and leukemia tumor cell lines by flow cytometry.

Using four human tumor cell lines, MCF-7 and T47-D from breast tumors, MOLT-4 and K-562 from leukemia, flow cytometric DNA analysis of pure and mixed cell population was performed using monoclonal antibodies to cytokeratin to distinguish cytokeratin-containing carcinoma cells from leukemia cells which do not contain cytokeratins. Surprisingly, on pure or mixed K-562 cells, we found positive labeling with KL1, CK8, and CK18 antibodies (results confirmed by immunocytology). This preliminary study has allowed a DNA analysis on epithelial cells of human breast tumors.

Adenocarcinoma↗

PubMed1988

Association of adriamycin-induced resistance to NK-mediated lysis with sialic acid level and immunological reactivity of transferrin receptors and glycophorin A.

Adriamycin (ADM) can increase sialic acid content in K 562 cells and reduce their susceptibility to NK-mediated lysis. In this report, hypothetical relationship between this resistance and augmentation in sialylation has been investigated. Variations in the time of exposure to ADM showed that 12 hours were sufficient to cause maximal recruitment of benzidine-positive cells, growth inhibition and resistance to NK-mediated lysis. On the contrary, the membrane sialic acid density seemed stable and 24 hours of drug exposure were necessary to observe a clear rise in sialic acid. Neuraminidase treatment of control and ADM-treated K 562 cells was associated with an obvious enhancement in their susceptibility to NK-mediated lysis which can be explained by an increase in the target-effector binding ability as assessed by a direct conjugate-forming cell assay. However, the neuraminidase treatment did not modify the sensitivity difference to lysis between untreated and ADM-treated cells. As compared to control the reactivity of ADM-treated cells was higher with an antiglycophorin A (GPA) MAb and lower with an antitransferrin receptor (TFR) MAb. Kinetic studies suggested that GPA expression is a better index of ADM-induced resistance to NK-mediated lysis than TFR expression. In addition, neuraminidase treatment showed that TFR and GPA modulations induced by ADM can be correlated with sialylation alterations.

Cell Line↗

PubMed1988

Effect of a pulsed magnetic field on tumoral C3H/Bi female mice.

Female C3H/Bi mice develop spontaneous viral mammary carcinoma which can metastasize to the lungs. Two hundred and forty tumoral mice were either exposed to a toroïdal pulsed magnetic field, 12 Hz, 100 Hz or 460 Hz in frequency or used as controls. The exposure was mainly done 10 min. a day, 3 days a week, or 30 minutes once a week from about 2 to 3 weeks after the appearance of the tumors until death. In comparison with the controls, the exposed mice showed lighter spleens and lungs; this last observation could mean fewer pulmonary metastases. The weight of the tumors has been found lighter for 460 Hz MF, not changed for 100 Hz MF, heavier for 12 Hz MF, but lifespans were not altered by the exposure.

Animals↗

PubMed1987

Age related differences in immunocompetence and incidence of mammary adenocarcinoma in murine mammary tumor virus-infected C3H/Bi mice.

In breeder C3H/Bi female mice, infected neonatally by murine mammary tumor virus (MTV), the incidence of spontaneous mammary tumors is greater than 95% between 5 and 9 months of age. In young (2-3 months) female the probability for developing a tumor in the next month is negligible, higher than 80% in mice of middle age (5-6 months) but lower than 4% in aged (10-12 months) females. The age-related changes of some immune functions of spleen cells from these tumor free female mice have been evaluated. While the proliferative capacity of cells to Phytohemagglutinin (PHA) increases, the T cell-dependent antibody response against sheep red blood cells (SRBC) and the antibody-dependent cellular cytotoxicity (ADCC) are significantly decreased in 5-6-month-old mice as compared to the young (2-3 months) female mice. The antibody response against SRBC and the mitogenic response to PHA decline markedly in 10-12-month-old mice but the ADCC increases in this group of mice. In addition, assays with monoclonal anti-Lyt-1 and anti-Lyt-2 antibodies indicate that percentage of Lyt 1- 2+ cells (suppressor and cytotoxic T cells) is lower in 10-12-month-old female as compared to 5-6-month-old animals. These results show that the immune alterations observed in 10-12-month-old C3H/Bi mice are not closely associated with an increase in incidence of spontaneous tumors and suggest that a high non-T killer cell activity could protect some of these older C3H/Bi female mice against mammary tumor development.

Aging↗