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Papers by Brigitte Bouchard

PubMed, Sep 1, 1994

Protein kinase C (PKC) is known to be involved in cellular proliferation and differentiation. In ... more Protein kinase C (PKC) is known to be involved in cellular proliferation and differentiation. In this work, we have investigated the effects of a novel PKC inhibitor, GF 109203X, on normal human fibroblast and keratinocyte growth. GF 109203X selectively inhibited PKC activity extracted from either fibroblasts (IC50 = 0.01 microM) or keratinocytes (IC50 = 0.4 microM). The inhibitory effects of GF 109203X on total PKC activity and Ca(2+)-independent PKC activity were similar. Nevertheless, in keratinocytes Ca(2+)-independent PKC activity represented 95% of total PKC activity, whereas in fibroblasts it corresponded to only 32% of total PKC activity. GF 109203X also inhibited a cellular function related to PKC activity in living fibroblasts and keratinocytes; it blocked the inhibitory effect of 12-O-tetradecanoylphorbol-13-acetate on 125I-epidermal growth factor binding. GF 109203X inhibited fibroblast growth, in terms of tritiated thymidine incorporation and cell counts, in a dose-dependent manner. We also observed that GF 109203X at 1 microM inhibited serum stimulation of expression of mRNA for c-fos and c-jun, which are usually involved in cellular proliferation. These results suggest that PKC stimulates fibroblast growth. In contrast, GF 109203X stimulated keratinocyte growth. We also observed that GF 109203X inhibited c-fos and c-jun mRNA expression in these cells. In fact, in keratinocytes these proto-oncogenes would be involved in the cellular differentiation process rather than in cellular proliferation. This suggests that the inhibition of PKC favors keratinocyte proliferation probably by inhibiting their differentiation. Thus, using GF 109203X, we show that PKC is involved differently in human fibroblast and keratinocyte growth.

Blood, Dec 1, 1992

Cytokines are important modulators of host antitumor responses. Two of these cytokines, interleuk... more Cytokines are important modulators of host antitumor responses. Two of these cytokines, interleukin-2 (IL-2) and interferon y (IFN-y), are produced after antigen-induced activation of helper lymphocytes. The cytokines are released into the immediate vicinity where they either interact with the appropriate receptors on effector cell populations or are rapidly degraded. To mimic this physiologic release of cytokines at the effector-target site, we used retroviral vectors to transduce melanoma cells with the IL-2 or IFN-y cDNA. Five melanoma cell lines were transduced with IL-2-or IFN-ycontaining vectors and secreted IL-2 at 1 to 40 U/mL/106 cells/24 h or IFN-y 1 to 8 U/mL/106 cells/24 h, respectively. After y irradiation, these cells continued to secrete cytokines for about 3 to 4 weeks. Secretion of IFN-y induced upregula-URRENT therapeutic approaches for metastatic mel-C anoma are inadequate. Therapeutic approaches that

M S-medecine Sciences, 1993

Proceedings of the American Association for Cancer Research Annual Meeting, Nov 11, 1989

<b>Copyright information:</b>Taken from "Analysis of prolactin-modulated gene ex... more <b>Copyright information:</b>Taken from "Analysis of prolactin-modulated gene expression profiles during the Nb2 cell cycle using differential screening techniques"Genome Biology 2000;1(4):research0008.1-research0008.15.Published online 16 Oct 2000PMCID:PMC15026.Copyright © 2000 GenomeBiology.com General principles. Messenger RNAs from the different cell populations (cells A and B) are reverse transcribed. Multiplex PCR is then performed using specific primer pairs to amplify the cDNAs of interest. The resulting mixture of PCR products is radiolabeled and these complex probes are used to hybridize identical membranes spotted with the candidate gene cDNA targets. After autoradiography, the intensities of the hybridization signals are compared and quantified. Arrows indicate the positions of differentially expressed genes. The absence of hybridization (open circles) indicates that the candidate gene is not expressed. Efficiency of the technique and examples of differentially expressed genes. The expression of different candidate genes was compared in either unsynchronized (UN), growth-arrested (GA), G1 phase (G1), G1/S transition (G1/S) or G2 phase (G2) cultures of Nb2 cells. The efficiency of the technique was controlled using equivalent amounts of rabbit α and β globin cDNAs, which were included on the nylon membranes along with the candidate gene targets. The two globin cDNAs were added in different amounts (50 or 150 ng) to each cDNA population before co-amplification. For each population tested, filters were hybridized with both globin probes, but only representative hybridization signals are shown, for either α (Panel A) or β (Panel B) globin. Numbers 1 and 3 represent the relative amount of the control rabbit globin cDNAs added, and are reflected in the differences in the intensity of the hybridization signals. Thus, a threefold difference in the quantity of a particular transcript in the initial population generates a clear difference in the intensity of the corresponding hybridization signals. Rows C, D, [...]

Development, 1991

The pigment cells of the skin are derived from melanoblasts which originate in the neural crest. ... more The pigment cells of the skin are derived from melanoblasts which originate in the neural crest. The dorsoventral migration of melanoblasts has been visualized in pigment stripes seen in aggregation chimeras, and the width of these bands has suggested that the entire pigmentation of the coat is derived from a small number of founder cells. We have generated mosaic mice by marking single melanoblasts in utero to gain information on the clonal history of pigment-forming cells. A retroviral vector carrying the human tyrosinase gene was constructed and microinjected into neurulating albino mouse embryos. Albino mice are devoid of pigmentation due to deficiency of tyrosinase. Thus, transduction of the wild-type gene into the otherwise normal melanoblasts should rescue the mutant phenotype, giving rise to patches of pigmentation, which correspond to the area colonized by the mitotic progeny of a marked clone. Mosaic animals derived from the injected embryos indeed showed pigmented bands w...

Blood, 1992

Cytokines are important modulators of host antitumor responses. Two of these cytokines, interleuk... more Cytokines are important modulators of host antitumor responses. Two of these cytokines, interleukin-2 (IL-2) and interferon gamma (IFN-gamma), are produced after antigen-induced activation of helper lymphocytes. The cytokines are released into the immediate vicinity where they either interact with the appropriate receptors on effector cell populations or are rapidly degraded. To mimic this physiologic release of cytokines at the effector-target site, we used retroviral vectors to transduce melanoma cells with the IL-2 or IFN-gamma cDNA. Five melanoma cell lines were transduced with IL-2- or IFN-gamma-containing vectors and secreted IL-2 at 1 to 40 U/mL/10(6) cells/24 h or IFN-gamma 1 to 8 U/mL/10(6) cells/24 h, respectively. After gamma irradiation, these cells continued to secrete cytokines for about 3 to 4 weeks. Secretion of IFN-gamma induced upregulation of major histocompatibility complex class I molecules in a subset of melanoma cell lines. IL-2 production by human melanoma xe...

Journal of Investigative Dermatology, 1996

Melanocytic cells can produce two types of pigment, pheomelanin or eumelanin. We used two types o... more Melanocytic cells can produce two types of pigment, pheomelanin or eumelanin. We used two types of human melanoma cell lines to explore the regulation of pigmentation by biochemical and enzymatic studies. These two cell lines were previously designated as either pheomelanotic or of mixed type when cultured in a medium rich in cysteine. We analyzed the effects of L-cysteine depletion on melanin synthesis and the involvement of the tyrosinase-related proteins in the production of both eumelanin and pheomelanin. Cultures were exposed to L-cysteine concentrations ranging from 206 to 2.06 microM, and the following parameters were measured: tyrosine hydroxylase activity, intracellular L-cysteine and glutathione concentrations, eumelanin and pheomelanin formation, and tyrosinase-related protein-1 and -2 mRNA levels. Extracellular L-cysteine depletion significantly increased tyrosine hydroxylase activity and promoted both eumelanogenesis and visible pigmentation in both lines. In contrast, pheomelanogenesis was increased only in the pheomelanotic cell line. Whereas eumelanogenesis was apparent upon L-cysteine depletion, tyrosinase-related protein-1 expression was not induced in the pheomelanotic cells, and tyrosinase-related protein-2 expression remained unchanged. Thus, tyrosinase-related protein-1 mRNA expression seems to be concomitant with eumelanogenesis when the L-cysteine concentration is high, but does not appear essential for eumelanogenesis at low L-cysteine concentrations. The mechanisms governing pheomelanin to eumelanin balance are dependent on L-cysteine, glutathione, and tyrosinase-related protein-1 expression, but none of these factors alone appears to be dominant in directing the synthesis of a particular type of melanin.

Medecine Therapeutique Endocrinologie, Oct 12, 2000

Ms Medecine Sciences, 2001

Investigative Ophthalmology Amp Visual Science, 2001

PURPOSE. To determine whether prolactin receptor is essential for normal development and function... more PURPOSE. To determine whether prolactin receptor is essential for normal development and function of the lacrimal gland and whether hyperprolactinemia can alter lacrimal development. METHODS. Lacrimal gland morphology and function were examined in two genetic mouse models of prolactin action: a prolactin receptor knockout model that is devoid of prolactin action and a transgenic model of hyperprolactinemia. RESULTS. Image analysis of lacrimal and Harderian gland sections was used to quantify glandular morphology. In females, lacrimal acinar area decreased by 30% and acinar cell density increased by 25% over control subjects in prolactin transgenic animals, but prolactin receptor knockout mice showed no changes. In males, transgenic animals showed no changes, but prolactin receptor knockout mice showed a 5% reduction in acinar area and an 11% increase in acinar cell density, which was lost after castration. The morphology of the Harderian glands underwent parallel changes but to a lesser degree. A complete loss of porphyrin accretions was seen in the Harderian glands of male and female knockout animals. No differences in tear protein levels were seen in knockout animals by two-dimensional gels. Enzyme-linked immunosorbent assay (ELISA) and Western blot analysis showed that the level of secretory component and IgA in knockout mouse tears remained unchanged. There was no change in the predisposition of the 129 mouse strain to conjunctivitis in the knockout animals. CONCLUSIONS. Prolactin plays a small role in establishing the sexual dimorphism of male lacrimal glands. In females, hyperprolactinemia causes a hyperfemale morphology, suggesting a role in dry eye syndromes. Prolactin is required for porphyrin secretion by the Harderian gland but plays no essential role in the secretory immune function of the lacrimal gland. (Invest

Prolactin, 2001

ABSTRACT The initial step in the mechanism of action of prolactin (PRL) is the binding to a cell ... more ABSTRACT The initial step in the mechanism of action of prolactin (PRL) is the binding to a cell surface receptor. Binding of PRL to its receptor occurs with a high affinity (association constants range from 107 to 1010 M-1) and a structural specificity. PRL receptors (PRLR) have been identified in a number of cell types and tissues in several species including non-mammalian vertebrates. PRLR belongs to the class I cytokine receptor superfamily. Signal transduction by the PRLR is mainly mediated by two families of signaling molecules; the Janus tyrosine kinases and the signal transducers and activators of transcription (STATs). Disruption of the PRLR gene has provided a new mouse model with which to identify functions directly associated with PRL. Several phenotypes have been analyzed which are described in this review. Applied to the SAGE technology, the PRLR knock-out model allows the quantitative and qualitative evaluation of the expression patterns of hepatic genes in two physiological situations: transcriptomes corresponding to livers from both wild type and PRLR KO mice are being compared, and following statistical analyses, candidate genes presenting a differential profile will be further characterized.

Obstetrical & Gynecological Survey, 1999

Journal of Investigative Dermatology, 1994

PubMed, Sep 1, 1994

Blood, Dec 1, 1992

M S-medecine Sciences, 1993

Proceedings of the American Association for Cancer Research Annual Meeting, Nov 11, 1989

Development, 1991

Blood, 1992

Cytokines are important modulators of host antitumor responses. Two of these cytokines, interleuk... more Cytokines are important modulators of host antitumor responses. Two of these cytokines, interleukin-2 (IL-2) and interferon gamma (IFN-gamma), are produced after antigen-induced activation of helper lymphocytes. The cytokines are released into the immediate vicinity where they either interact with the appropriate receptors on effector cell populations or are rapidly degraded. To mimic this physiologic release of cytokines at the effector-target site, we used retroviral vectors to transduce melanoma cells with the IL-2 or IFN-gamma cDNA. Five melanoma cell lines were transduced with IL-2- or IFN-gamma-containing vectors and secreted IL-2 at 1 to 40 U/mL/10(6) cells/24 h or IFN-gamma 1 to 8 U/mL/10(6) cells/24 h, respectively. After gamma irradiation, these cells continued to secrete cytokines for about 3 to 4 weeks. Secretion of IFN-gamma induced upregulation of major histocompatibility complex class I molecules in a subset of melanoma cell lines. IL-2 production by human melanoma xe...

Journal of Investigative Dermatology, 1996

Medecine Therapeutique Endocrinologie, Oct 12, 2000

Ms Medecine Sciences, 2001

Investigative Ophthalmology Amp Visual Science, 2001

Prolactin, 2001

Obstetrical & Gynecological Survey, 1999

Journal of Investigative Dermatology, 1994