c-myc gene amplification in selected node-negative breast cancer patients correlates with high rate of early relapse

In breast cancers with histologically negative axillary nodes selected for high frequency of recurrence, the amplification of c-myc, erbB-2 and int-2 genes was found to concern, respectively 25% (16/65), 31% (25/81) and 14% (10/70) of tumours. Their relation with tumour progression expressed by relapse-free survival is reported. Using univariate analyses, c-myc amplified tumours showed significant association with early (30-month period after diagnosis) (P = 0.0013) and intermediate (50-month period after diagnosis) (P = 0.0398) risks of recurrence. In contrast, only a trend towards higher relapse was observed in erbB-2 amplified breast cancers with respect to later events (occurring over the first 30-month period). Multivariate analyses indicated that c-myc amplification is an independent prognostic factor stronger than oestrogen receptor status and tumour size to define a high risk subset in node-negative patients selected for high frequency of recurrence.

Estradiol and EGF requirements for cell-cycle progression of normal human mammary epithelial cells in culture

The purpose of our study was to show the feasibility of accurately investigating the factors likely to control cell proliferation of normal human mammary epithelial (HME) cells, using a scanning cytometric method. The methodology was previously developed with the SAMBA 200 cell image processor to characterize in situ the cell-cycle phases of HME cells. Since various compartments constitute the mammary epithelium, cells obtained after reduction mammoplasty were cultured in a medium with a low calcium content (0.06 mM) to provide proliferating normal HME cells while maintaining their differentiation characteristics. Estradiol and EGF requirements for cell-cycle phase progression of these cells were examined. Then, we showed that 2 normal HME cell cultures displaying different phenotypic characteristics may differently progress through the cell cycle under the same hormonally defined conditions. Cell-cycle progression of the epithelial cells presenting luminal phenotype was induced only by sequential stimulation/pretreatment with estradiol followed by EGF treatment; this progression was enhanced when estradiol was maintained during EGF treatment. This definite order demonstrated that estradiol could have a permissive effect on EGF mitogenic activity. In contrast, epithelial cells likely to be localized in the basal position in the mammary gland showed the same proliferating activity whatever the estradiol and EGF treatment. These cells progressed profusely in cell cycle, independent of exogenous estradiol and EGF contribution, but they remained sensitive to estradiol regarding EGF-receptor detection. Our results suggest autonomous proliferation of these cells through an autocrine pathway, in the absence of negative regulators.

Cumulative mortality rates in Aedes polynesiensis after feeding on polynesian Wuchereria bancrofti carriers treated with single doses of ivermectin, diethylcarbamazine and placebo

During a therapeutic trial, batches of 672 to 1979 laboratory-bred Aedes polynesiensis, the mosquito vector of lymphatic filariasis in French Polynesia, were fed on Wuchereria bancrofti carriers one, three and six months after they had been treated with either single doses of ivermectin at 100 mcg/kg, diethylcarbamazine (DEC) at 3 and 6 mg/kg or placebo. High mortality rates were observed during the 15-day period following the blood-meal in mosquitoes fed on carriers treated with microfilaricidal drugs and were significantly higher in mosquitoes fed on carriers treated with ivermectin than in those fed on carriers treated with DEC. Though its intensity decreased with the passage of time, the phenomenon was observed in mosquitoes fed on carriers up to six months after treatment, especially in those fed on carriers treated with ivermectin. By decreasing the number of mosquitoes able to transmit the infection, this lethal effect on Ae. polynesiensis might represent an additional advantage of ivermectin in lymphatic filariasis control programs.

Single versus repeated doses of ivermectin and diethylcarbamazine for the treatment of Wuchereria bancrofti var. pacifica microfilaremia. Results at 12 months of a double-blind study

In October 1989, 58 apparently healthy Polynesian Wuchereria bancrofti carriers in whom microfilarial (mf) density was greater than or equal to 100 mf/ml were randomly allocated to treatment groups receiving single doses of either ivermectin at 100 mcg/kg or diethylcarbamazine (DEC) at 3 and 6 mg/kg. Six months later, half of the carriers initially treated with ivermectin 100 mcg/kg or DEC 3 mg/kg were given a second similar dose while the rest were given a placebo. By day 360 (6 months after retreatment), comparison of adjusted geometric mean mf counts per group indicated that (i) among the 3 treatments given once a year the DEC 6 mg/kg dose resulted in the highest efficacy, (ii) nevertheless, regarding either ivermectin 100 mcg/kg or DEC 3 mg/kg, 2 successive doses resulted in higher efficacy than one annual dose and (iii) though no significant difference could be evidenced between efficacy of ivermectin 100 mcg/kg and DEC 3 mg/kg given twice a year, DEC seemed to sustain the mf reduction for a longer period of time. During the 3 days following retreatment, adverse reactions (mild to moderate) were observed in 46% of carriers treated with microfilaricidal drugs and in 20% of those treated with placebo. These results suggest that single dose therapy with either DEC or ivermectin is safe and effective for prevention of lymphatic filariasis due to Wuchereria bancrofti in French Polynesia. The real impact on transmission by the vector, Aedes polynesiensis, of the complete negativation of microfilaremia observed during the previous part of the trial in carriers treated with ivermectin should be evaluated in a community-based trial including entomological study.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic values of ELISA-IgG4 as compared to ELISA-IgG and indirect immunofluorescence, for the routine diagnosis of bancroftian filariasis in the South Pacific. Application on capillary blood collected on filter paper

For the serodiagnosis of lymphatic filariasis, serological assays restricted to the detection of specific IgG4 antibodies enhanced the specificity. In French Polynesia, Wuchereria bancrofti is the sole human filaria and other pathogenic parasites are infrequent. In order to define a simple and cheap serological test, we have compared the diagnostic value of indirect immunofluorescence test (IFI-WBp), ELISA-IgG and ELISA-IgG4 assays. The specificity, sensitivity, R.O.C. curves of each test have been analyzed. No significant difference was found between those 3 tests, except that the reproducibility and the predictive value were lower using IFI-WBp than using the two ELISAs. Significant correlation was found between IgG and IgG4 anti-Brugia malayi antibody titers (r = 0.512, p less than 10(-5)). For large scale seropidemiological studies, ELISA-IgG can be performed with finger prick blood absorbed on filter paper, but not ELISA-IgG4. In conclusion, ELISA-IgG a less expensive and less time consuming method than ELISA-IgG4, can be used for the routine serodiagnosis as well as for seroepidemiological studies on bancroftian filariasis in the South Pacific islands.

Neurochemical and immunocytochemical studies of catecholamine system in the brindled mouse

The distribution of immunoreactive catecholamine neurons and fibers was investigated in brindled mottled mouse, a murine model of Kinky hair syndrome (KHS), using antisera against tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DBH). In all mice, including normal littermate controls, a transient increase of TH-immunoreactive neurons (TH-IN) was observed in the cerebral cortex during the second postnatal week. The numbers of TH-IN were more pronounced in hemizygous brindled males (MObr/y). In addition, TH-IN appeared and rapidly increased in number in the striatum of MObr/y after postnatal day 11 (P11). Striatal TH-IN were rarely detected in controls. After cupric chloride (CuCl2) treatment, TH-IN in the striatum of some of the MObr/y mice became less conspicuous. In the substantia nigra and ventral tegmental area where TH-IN are normally present, no differences either in the immunostaining of TH-IN or the pattern of TH immunoreactive fibers were detected between MObr/y and controls. In MObr/y, a superficial plexus of DBH immunoreactive fibers was more pronounced than in controls but there were no DBH immunoreactive neurons in the cerebral cortex or striatum in any of the mice examined. Neurochemical analysis revealed a marked decrease in norepinephrine levels and increase of serotonin and its metabolites in the brain in MObr/y. Together, these data suggest that the unusual expression of TH-IN in MObr/y represents perturbations of normal development of catecholamine neurons in this copper deficient mutant mouse.

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.

Cell cycle phase dependence of estrogen and epidermal growth factor (EGF) receptor expression in MCF-7 cells: implications in antiestrogen and EGF cell responsiveness

In this report the effect of epidermal growth factor (EGF) and the antiestrogen hydroxytamoxifen (OH-TAM) on the cell cycle of the breast cancer cell line MCF-7 was investigated as a function of the presence of their respective receptors. For this study synchronized cells were obtained by cell incubation in the presence of 2 mM thymidine for 24 h at 37 C. The treatment led to a partial synchronization, since at the end of thymidine treatment, 80% of cells were accumulated in the G1 phase. The removal of thymidine allowed the cells to progress through the cell cycle, since between 6-9 h after the arrest of the treatment, about 50% of cells were found in the S phase. By 9-12 h, most of the cells entered the G2 phase, and by 24 h, the cells returned to the G1 phase. When MCF-7 cells were incubated in the presence of OH-TAM for various periods of time before thymidine exposure, the progression of the cells through the cell cycle was dramatically inhibited. Also, a short term antiestrogen treatment (2 h) before or immediately after the addition of thymidine led to an accumulation of MCF-7 cells in the G1 phase. However, when the cells were treated for 2 h with OH-TAM 22 h after thymidine addition or shortly after its removal from the cell culture, no effect of the antiestrogen on the cell cycle could be observed. In parallel, the effect of thymidine on the level of estrogen receptor was studied. Although low affinity estrogen-binding sites were maintained, high affinity ER were found to be dramatically reduced during the thymidine treatment. The comparison between the effect of OH-TAM on the cell cycle and the expression of ER revealed that the antiestrogen OH-TAM was effective only in the presence of ER. EGF was found to have no effect on the cell cycle of thymidine-synchronized cells, although it did partially reverse the G1 phase block induced by OH-TAM when added simultaneously to cell culture 24 h before thymidine exposure. The parallel analysis of EGF receptor level demonstrated that thymidine treatment also reduced EGF receptors that were found to reappear after the synchronization, during the S and G2 phases of the cell cycle.(ABSTRACT TRUNCATED AT 400 WORDS)

The treatment of microfilaremia due to Wuchereria bancrofti var. pacifica: ivermectin versus diethylcarbamazine

In October 1989, a controlled, double-blind parallel group trial was implemented to compare both efficacy and tolerability of single doses of ivermectin and diethylcarbamazine (DEC). Fifty eight apparently healthy Wuchereria bancrofti carriers were hospitalized and randomly allocated to treatment with ivermectin 100 mcg/kg, DEC 3 or 6 mg/kg. Six months later, half of those initially treated with ivermectin 100 mcg/kg and DEC 3 mg/kg were given a second similar dose while the rest were given a placebo. After initial treatment, clearance of microfilaremia was complete in 22 of the 23 carriers treated with ivermectin and in one only of the 35 treated with DEC. Adjusted geometric mean microfilaremia was significantly lower (p less than 0.01) in carriers treated with ivermectin than in those treated with DEC at one, but neither at 3 (p = 0.26) nor at 6 months (p = 0.63). The comparison of adjusted geometric mean microfilaremia per group indicated that (i) regarding either ivermectin 100 mcg/kg or DEC 3 mg/kg, 2 successive doses resulted in higher efficacy than one annual dose and (ii) efficacy of 2 successive doses of ivermectin 100 mcg/kg or DEC 3 mg/kg were not significantly different. During the 3 days following initial treatment, adverse reactions were observed in 80% of the treated carriers of whom 14% suffered a grade 3 reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of oestrogen receptors: application of the Passing-Bablock linear regression technique for comparison of enzyme immunoassay and radioligand binding assay in 1841 breast cancer tumours

To test the qualities of two assays in the same laboratory on the same tumours, a single-point dextran-coated charcoal radioligand binding assay (RLA-DCC) and the Abbott enzyme immunoassay (EIA) were used to perform oestrogen receptor determinations on cytosols from 1841 breast cancers over a 2-year period. Statistical analysis of the data was performed by the Passing-Bablock linear regression technique. The final regression curve between EIA (y) and RLA-DCC (x) yielded y = 1.187 x fmol/mg of protein. However, a high variability in this correlation was observed from 1986 to 1988. This variability could be explained by calibration problems in the immunoassay kits and changes in our technical team. The binding assay appears to be more sensitive to the technicians' experience than the immunoassay. Other technical points are discussed, particularly cytosol preparation and KCl presence or absence in the homogenisation buffer. Finally, the Passing-Bablock and the least squares regression procedures are compared. The conditions allowing optimal correlation and routine determination reliability are defined and the correlation variability is discussed.

Genomic analysis of the 67-kDa laminin receptor in normal and pathological tissues: circumstantial evidence for retroposon features

We have cloned two cDNAs for the human 67-kDa laminin receptor (LR). In the present report we show that these clones hybridize to many restriction fragments in Southern experiments in human. This particular pattern is accounted for by the presence of up to 16 and 21 copies of the laminin receptor gene per haploid genome in human and mouse, respectively. In contrast, a single gene copy is found in chicken. Chromosomal localization reveals four main loci: LAMRP1, laminin receptor pseudogene 1 (Chr 3); LAMRP2, laminin receptor pseudogene 2 (Chr 12); LAMRP3, laminin receptor pseudogene 3 (Chr 14); LAMRP4, laminin receptor pseudogene 4 (Chr X). Comparison of our experimental results to the known features of processed retropseudogenes enabled us to conclude that the LR gene belongs to a retroposon family in mammals.

Effect of epidermal growth factor on the proliferation of human epithelial cancer cell lines: correlation with the level of occupied EGF receptor

In this report, we have studied the effect of epidermal growth factor (EGF) on the proliferation of breast cancer cell lines, as well as the modulation of estrogen -and epidermal growth factor - receptor levels by EGF treatment. We have observed that all the cell lines analysed were stimulated by EGF in low serum containing media. The MCF-7AZ cell line, its H-ras transfected MCF-7AZ TD5 variant and the MCF-7 cells, all of them containing a relatively low number of epidermal growth factor receptors, were growth stimulated in a dose-dependent manner by 10(-9) M to 10(-8) M EGF. The MDA-MB 231, A431 and BT20 cell lines that express higher receptor levels were stimulated with relatively low concentrations of epidermal growth factor (5 x 10(-13) M to 10(-11) M). However, A431 and BT20 cells were shown to be growth-inhibited in the presence of higher EGF concentrations (10(-10) M to 10(-8) M). We also observed that EGF down-regulated epidermal growth factor receptor while it up-regulated estrogen receptor. In addition, Scatchard analysis of radiolabeled EGF binding on cell surface demonstrated that the concentrations of growth factor necessary to occupy a given number of epidermal growth factor receptors are inversely correlated with the total level of these receptors. Our findings suggest that the mitogenic effect of epidermal growth factor on cell proliferation is a function of the quantity of EGF-occupied receptors.

Peripheral facial nerve palsy related to HIV infection: relationship with the immunological status and the HIV staging in Central Africa

Twelve cases of infranuclear facial nerve palsy associated with infection by the human immunodeficiency virus in the heterosexual African are reported with clinical and immunological studies. Eight cases were healthy HIV carriers, three patients manifested AIDS-related complex and one case fulfilled the CDC criteria for AIDS. Nine patients had a typical Bell's palsy, two presented cephalic Herpes zoster infection with Ramsay Hunt syndrome and one, who suffered from progressive facial weakness, could be considered as having a cephalic form of Guillain-Barré syndrome.

A multiparametric analysis of endometrial estrogen and progesterone receptors after the postovulatory administration of mifepristone

A double-blind randomized study was performed in two groups of eight normally cycling patients: group I received 10 mg/d of RU486 for 4 days from the date of ovulation and group II received a placebo. On day +5, cytosol and endometrial estrogen receptors (ERs), and progesterone receptors (PRs) were analyzed by radioligand binding assay as well as by enzyme immunochemistry. Histologic studies showed that all the endometria of group I were abnormal (luteal insufficiency and/or E/P imbalance). The nuclear PR levels were significantly higher in group I (843 +/- 422 fmol/mg) deoxyribonucleic (DNA) compared with 482 +/- 232 fmol/mg DNA in group II. Immunohistochemical study showed that ER and PR staining was higher for both glands and stroma in group I (52% and 72% for the respective receptors), compared with the receptor-immunostained surface observed in group II, which was reduced to 40% for ER and to 4% for PR. This study demonstrates that RU486 administered in the immediate postovulatory period blocks normal tissue evolution in the follicular phase as well as the processing of PR.

Distinct effects of gonadotropin-releasing hormone analogs and 4-hydroxytamoxifen on pS2 mRNA expression with respect to cell proliferation in MCF-7 breast cancer cells

Gonadotropin-releasing hormone (GnRH) analogs and antiestrogens display direct antiestrogenic effects on the proliferation of hormone-sensitive breast cancer cells. This study aimed to determine whether growth inhibition of 17 beta-estradiol-stimulated MCF-7 breast cancer cells by the agonist D-Trp6 GnRH, the GnRH antagonist BIM 21009C and 4-hydroxy-tamoxifen (OHT) respectively occurred through alterations of the estrogen receptor (ER)-mediated intracellular pathway. The pS2 mRNA expression is primarily dependent on activated ER in MCF-7 cells, and pS2 protein could act as a growth factor. Drug effect on pS2 mRNAs were qualitatively compared to those on the cell cycle. Unlike OHT, GnRH analogs did not suppress the 17 beta-estradiol-induced pS2 mRNA expression whilst the cell cycle was blocked. The pS2 mRNA expression was induced by D-Trp6 GnRH alone without effect on the cell cycle. The outcome of our study is double. Firstly, GnRH analogs are distinct from OHT as regards their effects on the ER-mediated intracellular pathway. Secondly, pS2 mRNA expression is not strictly related to MCF-7 cell proliferation, suggesting that pS2 protein has a function other than that of critical growth regulator.

[Different regulation systems of cell cycle events (dysregulation of these events in the tumoral cell)]

Preservation of the shape and the integrity of multicellular eukaryotes needs rigorous cell proliferation monitoring. During the prereplicative G1 phase, a finely adjusted and specific control supervises the proliferant/non proliferant states of the cells. Some molecular mechanisms of growth regulation have been identified in recent years. Changes in normal cell attachment on extracellular matrix and intercellular chemical signalling (secretion of informative molecules) activate intracellular signals for division. The transduction mechanisms of the extracellular signalling to the nucleus have been partially elucidated for steroid hormones and growth factors. Molecular biology research and proto-oncogene discoveries have led to considerable progress in understanding the role of these normal genes in the control of cellular proliferation. The initiation of the response to extracellular factors requires: i), direct transducers (specific binding of the steroid hormone on its cytoplasmic or nuclear receptor and high affinity binding of this activated complex to specific DNA sequences); and ii) indirect transducers (binding of growth factors on extracellular domains of specific receptor proteins which convert this extracellular event into several intracellular signals, secondary messengers, protein kinases and specific nuclear regulatory factors). Whatever the transduction system, nuclear events control transcription of growth regulatory genes. The series of enzymatic reactions set in motion by indirect transduction systems require strict regulation systems, the diversity and the complexity of which has been perceived in studies on jun and fos gene families. Each proliferation step is governed by growth stimulators and growth inhibitors, the transformation of normal cells to cancer cells resulting from alterations of these regulatory process. Independent of extracellular stimuli and of their transfer to the nucleus, intracellular controls coordinate cell cycle phases (G1, S, G2 and M) to produce daughter cells identical to the original cell. Two control points are particularly critical: one in G1 (the "start" point) and the other in G2 just before mitosis. Although intermediate steps between extracellular and intracellular controls are still unknown, yeast gene analyses have allowed determination of molecular regulatory mechanisms implicated in the passage of these critical points. A considerable advance was made by the discovery that some of the involved components presented strong sequence and function homologies in organisms from yeast to man, suggesting a phyllogenetically conserved mechanism. It seems likely that the phosphorylation state of protein p34, its association with a G1-phase specific cyclin or a M-phase specific cyclin, and its protein kinase activity regulate the proliferation state of higher eukaryotic cells. In spite of significant advances, much research is still necessary to elucidate all the mechanisms involved in cell cycle control.

The female brindled mouse as a model of Menkes' disease: the relationship of fur pattern to behavioral and neurochemical abnormalities

The brindled mottled mutant mouse, a model of Menkes' disease, has alterations in copper homeostasis which cause, among other sequelae, neuronal degeneration in selected areas of brain. This work examined the neurochemical changes at postnatal days (PND) 15, 30 and 60 in females heterozygous for the sex-linked brindled mutation. These data were compared to behavioral alterations and to fur coat color at these same time points. The brindled heterozygotic females had lower concentrations of norepinephrine (NE) in the cingulate cortex, and higher levels of dopamine or dopamine metabolites in the cingulate cortex, thalamus and hypothalamus across all ages, although the difference was greatest at PND 15. The brindled females were much less active than their normal littermates at PND 15, but the differences were no longer evident at PND 30 and 60. Mottling of the fur is believed to result from low tyrosinase activity caused by abnormalities in copper metabolism. The fur pattern and behavior of the brindled mice were highly correlated with NE levels in the cingulate cortex and thalamus. These data show that female brindled mice have neurochemical abnormalities similar to (if less severe than) the male hemizygotes, that these abnormalities are regionally specific, are most apparent prior to 30 days of age, and are linked to behavioral deficits. These data also show that the extent of such deficits can be predicted by a quantitative analysis of the fur pattern of these females.

GnRH complementary peptide antibodies: outcome in GnRH receptor immunoanalysis

The aim of this study was to obtain gonadoptropin-releasing hormone (GnRH) receptor antibodies of high affinity for receptor immunoanalysis. According to the complementary peptide theory, complementary nucleic acid segments encode for the hormone ligand and the receptor binding site, respectively. On this premise, we used as immunogen, GnRH complementary peptide [N-terminal]Ser-Arg-Ala-Gln-Ser-Ile-Gly-Pro-Val-Leu conjugated with a carrier protein. High antibody titers were obtained in rabbits, rats and mice. Our antisera recognized the hydrophobic middle part of the GnRH complementary peptide. A band of protein with a molecular weight similar to that of the GnRH receptor (60 kDa) was specifically detected by immunoblot of solubilized rat pituitary membranes with the highest titering rabbit antiserum. In bioassays on sheep pituitary cells in vitro, some antisera inhibit basal or GnRH-induced LH secretion. In order to elicit antibodies of high affinity, we used a selective receptor assay on rat brain and pituitary sections where the ligand was the labeled agonist Des-Gly10-D-Ala6 GnRH. None of the highest titering antisera prevented the binding of such a high affinity ligand. The complementary peptide approach thus appears not to be optimal for obtaining high affinity antibodies against the GnRH receptor binding site.

Nuclear texture parameters as discriminant factors in cell cycle and drug sensitivity studies

The authors have recently shown that cell cycle characteristics of in situ cell populations can be determined using the SAMBA 200 cell image processor by computing 15 densitometric and texture parameters on each Feulgen-stained nucleus and multiparametric analysis of data. The present paper displays the importance of chromatin pattern assessment and detection of conformational changes in DNA structure, based on nine nuclear texture parameters measured from the grey level cooccurrence and the run-length section matrices. Reference files were constructed by merging respective reference files (G0/G1, S, G2 and M) of MDA AG and MCF-7, two mammary epithelial cell lines presenting different morphological aspects and hormone responses, these files were found to be valid in the reclassification of any mammary epithelial cell in culture with a diploid or near diploid pattern. Moreover, the authors demonstrate that chromatin texture changes, following direct interaction of chemotherapeutic drugs with DNA, may be assessed owing to nuclear texture parameters. Consecutive to daunomycin addition (0.5 microgram/ml) and concomitant to the appearance of nuclear morphological alterations in MDA AG sensitive cells as viewed by microscopic observation, discriminant factorial analysis showed progressively increasing erroneous reclassification from 15 to 72 h of treatment. These experimental results were exploited with a kinetic mathematical model to quantify the daunomycin blocking effect: 20% in S phase and 80% in G2 phase. Interestingly, no textural change was observed on MDA A1 anthracycline resistant cells, indicating that these texture parameters may permit distinction of drug sensitive cells. This methodology 1) can be applied to test in vitro resistance-reversal molecules, 2) may be extended to other therapeutic agents giving rise to conformational changes in DNA structure, and 3) can be applied to cytopunctions or imprints of tumor biopsies with diploid-like DNA content to follow evolution of drug sensitivity or resistance during course of therapy.

Modulation of tPA, PAI-1 and PAI-2 antigen and mRNA levels by EGF in the A431 cell line

It has been reported that EGF treatment enhances uPA but not tPA in the A431 epidermoid carcinoma cell line. To determine whether the absence of tPA modulation by EGF could be due to the action of inhibitors, we assayed tPA, PAI-1, PAI-2 and tPA/PAI-1 complexes by immunological assays and zymography in A431 serum-free medium. We found that, under conditions in which EGF had no effect on tPA activity, tPA antigen increased with a concomitant rise of tPA/PAI-1 complexes, indicating the action of an inhibitor. Both tPA antigen and tPA/PAI-1 complexes were modulated by EGF in a time and concentration dependent manner. tPA/PAI-1 complex levels were lower than tPA levels, suggesting the presence of other inhibitors. Immunological assays detected PAI-2 in addition to PAI-1 and showed a time and dose response to EGF. Modulation of tPA and the anti-activators by the growth factor was confirmed by identification of the corresponding transcripts with cDNA probes. We conclude that the net plasminogen activator activity in A431 cells is the result of a balance between activators and inhibitors.

Concomitant secretion by A431 cells of tissue plasminogen activator and a specific inhibitor masks EGF modulation of tPA activity

It has previously been reported that EGF enhances uPA but not tPA in the A431 squamous carcinoma cell line. To determine whether the absence of tPA modulation by EGF reflected steady levels or the action of an anti-activator, we assayed tPA, PAI-1 and tPA/PAI-1 complexes by zymography and immunological assays. Under conditions in which EGF had no effect on tPA activity, tPA antigen paradoxically increased with a concomitant rise of tPA/PAI-1 complexes. This indicated that tPA was rapidly inactivated through the formation of a complex, immunologically and electrophoretically related to tPA/PAI-1. tPA antigen and tPA/PAI-1 complexes were modulated by EGF in a time and concentration dependent manner. PAI-1 antigen was secreted into A431 medium (CM) after a lag phase of 16 h in both control and EGF-treated cultures. Evidence is presented here that two forms of PAI-1 are present in A431 CM: an inactive form and an active form which neutralizes the tPA secreted, masking its enhancement by EGF in functional assays.

Expression of estrogen receptor and its messenger ribonucleic acid in the MCF-7 cell line: multiparametric analysis of its processing and regulation by estrogen

Experimentally, a portion of the detectable cellular estrogen receptor (ER) is seen to disappear in human breast cancer cells submitted to estradiol treatment. In this study, we have applied several detection methods to analyze the loss (processing) then the replenishment of ER in the MCF-7 cell line. Radioligand exchange assay and enzyme immunoassay revealed an accumulation of ER in the nuclei with a concomitant depletion in cytosol shortly after the addition of estradiol in cell culture. Then, a time-dependent decrease of ER level in the nuclear compartment without rescue in the cytosol was observed. When an immunocytochemical assay was performed on whole cells treated with estradiol, a similar decrease of ER number was shown, indicating that a decrease in the extractability of estradiol-filled ER was not involved in the processing. Analysis of ER mRNA also indicated that the estrogen treatment induces a time-dependent decrease of its expression. Measurement of [35S]methionine-labeled ER following the arrest of the hormone treatment suggested that ER replenishment was due to newly synthesized receptors. Sucrose gradient experiments confirmed the generation of small molecular forms of ER, following its binding with estradiol. All these data are indicative of estrogen-receptor complex degradation. We also confirm that estrogen regulates ER level through the decrease of its mRNA expression.