Assessment of Epiregulin Effect and its Combination with Gonadotropins on Proliferation, Apoptosis, and Secretory Activity by Human Ovarian Cells.

The release of epidermal growth factor ligand epiregulin (EREG) by human ovarian granulosa cells, its direct action on basic ovarian cell functions, and interrelationships with gonadotropins were investigated. We examined (1) the ovarian production of EREG (the time-dependent accumulation of EREG in the medium incubated with human ovarian granulosa cells, and (2) the effect of the addition of EREG (0, 1, 10, and 100 ng.ml-1) given alone or in combination with FSH or LH (100 ng.ml-1) on basic granulosa cells functions. Viability, proliferation (accumulation of PCNA and cyclin B1) and apoptosis (accumulation of bax and caspase 3), the release of steroid hormones (progesterone, testosterone, and estradiol), and prostaglandin E2 (PGE2) were analyzed by using the Trypan blue exclusion test, quantitative immunocytochemistry, and ELISA. A significant time-dependent accumulation of EREG in a medium cultured with human granulosa cells with a peak at 3 and 4 days was observed. The addition of EREG alone increased cell viability, proliferation, progesterone, testosterone, and estradiol release, decreased apoptosis, bud did not affect PGE2 release. The addition of either FSH or LH alone increased cell viability, proliferation, progesterone, testosterone, estradiol, and PGE2 release and decreased apoptosis. Furthermore, both FSH and LH mostly promoted the stimulatory action of EREG on granulosa cell functions. These results demonstrated, that EREG produced by ovarian cells can be an autocrine/paracrine stimulator of human ovarian cell functions. Furthermore, they demonstrate the functional interrelationship between EREG and gonadotropins in the control of ovarian functions.

A multi-omic analysis of MCF10A cells provides a resource for integrative assessment of ligand-mediated molecular and phenotypic responses.

The phenotype of a cell and its underlying molecular state is strongly influenced by extracellular signals, including growth factors, hormones, and extracellular matrix proteins. While these signals are normally tightly controlled, their dysregulation leads to phenotypic and molecular states associated with diverse diseases. To develop a detailed understanding of the linkage between molecular and phenotypic changes, we generated a comprehensive dataset that catalogs the transcriptional, proteomic, epigenomic and phenotypic responses of MCF10A mammary epithelial cells after exposure to the ligands EGF, HGF, OSM, IFNG, TGFB and BMP2. Systematic assessment of the molecular and cellular phenotypes induced by these ligands comprise the LINCS Microenvironment (ME) perturbation dataset, which has been curated and made publicly available for community-wide analysis and development of novel computational methods ( synapse.org/LINCS_MCF10A ). In illustrative analyses, we demonstrate how this dataset can be used to discover functionally related molecular features linked to specific cellular phenotypes. Beyond these analyses, this dataset will serve as a resource for the broader scientific community to mine for biological insights, to compare signals carried across distinct molecular modalities, and to develop new computational methods for integrative data analysis.

Eficacia y seguridad de afatinib como tratamiento de primera línea en pacientes adultos con cáncer de pulmón de células no pequeñas avanzado (estadios IIIB/IV), con mutaciones activadoras del gen del receptor del factor de crecimiento epidérmico, con contraindicación a erlotinib por hipersensibilidad / Efficacy and safety of afatinib as first-line treatment in adult patients with advanced non-small cell lung cancer (stages IIIB/IV), with activating mutations of the epidermal growth factor receptor gene, with contraindication to erlotinib due to hypersensitivity

INTRODUCCIÓN: El cáncer de pulmón de células no pequeñas (CPCNP) es la causa más frecuente (85 % - 90 %) de tumores pulmonares malignos que generalmente afectan a adultos que fuman y que tienen ≥ 65 años. En Perú, en 2017, el cáncer de pulmón fue la segunda causa de muerte entre todos los cánceres, con una mortalidad anual de 8.8 muertes por cada 100,000 personas.  La terapia de primera línea del CPCNP avanzado (estadio IIIB/IV) depende del estado de las mutaciones conductoras oncogénicas, la expresión de PD-L1 y la histología. Así, para los casos en los que se detecta una mutación sensibilizante1 del receptor de factor de crecimiento epidérmico (EGFR, por sus siglas en inglés), se recomienda ofrecer una terapia dirigida contra el EGFR utilizando los inhibidores de la tirosina quinasa del EGFR (de aquí en adelante llamados TKI, por sus siglas en inglés) de primera línea (e.g., erlotinib, afatinib).  En el Seguro Social de Salud del Perú (EsSalud), los pacientes con CPCNP avanzado cuyos tumores poseen mutaciones positivas2 del EGFR disponen de erlotinib como tratamiento de primera línea según lo establecido en el Petitorio Farmacológico de EsSalud. Sin embargo, existe un grupo de pacientes que presentan eventos adversos (EA) cutáneos severos (grado 3 o mayor) asociados al tratamiento con erlotinib, quienes, en ciertos casos, requerirán de la discontinuación de uso del medicamento, a pesar del manejo óptimo de las toxicidades cutáneas (e.g., reducción de dosis). En este grupo de pacientes con hipersensibilidad a erlotinib (contraindicación de uso), los médicos especialistas de la institución sugieren el uso de un TKI alternativo: afatinib. OBJETIVO: Evaluar la mejor evidencia disponible sobre la eficacia y seguridad de afatinib, en comparación con la quimioterapia, en pacientes adultos con CPCNP avanzado, con mutaciones activadoras3 del gen del EGFR, con contraindicación a erlotinib por hipersensibilidad. TECNOLOGÍA SANITARIA DE INTERÉS: Afatinib: Afatinib es un inhibidor selectivo e irreversible de la actividad de la tirosina quinasa de los receptores de la familia ErbB: EGFR (ErbB1), HER2 (ErbB2), HER3 (ErbB3) y HER4 (ErbB4). Afatinib se une en forma covalente a los dominios de la tirosina quinasa de estos receptores e inhibe irreversiblemente la autofosforilación de la tirosina quinasa, lo que resulta en un bloqueo de las señales de los receptores ErbB (European Medicines Agency 2019). METODOLOGÍA: Se realizó una búsqueda sistemática de literatura con el objetivo de identificar evidencia sobre la eficacia y seguridad de afatinib, en comparación con la quimioterapia, en pacientes adultos con CPCNP avanzado, con mutaciones activadoras del gen del EGFR, con contraindicación a erlotinib por hipersensibilidad. Se utilizó la base de datos The Cochrane Library, PubMed, LILACS y el metabuscador TRIP Database, priorizándose evidencia proveniente de ensayos clínicos aleatorizados. Asimismo, se realizó una búsqueda dentro de bases de datos pertenecientes a grupos que realizan evaluaciones de tecnologías sanitarias y guías de práctica clínica, incluyendo el Scottish Medicines Consortium (SMC), el National Institute for Health and Care Excellence (NICE), la Canadian Agency for Drugs and Technologies in Health (CADTH), la Haute Autorité de Santé (HAS), el Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen (IQWiG), además de la Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas (BRISA) y páginas web de sociedades especializadas en cáncer de pulmón. Se hizo una búsqueda adicional en la página web de clinicaltrials.gov, para poder identificar ensayos clínicos en curso o que no hayan sido publicados para, de este modo, disminuir el riesgo de sesgo de publicación. La búsqueda sistemática se basó en una metodología escalonada, la cual consistió en la búsqueda inicial de estudios secundarios (tipo revisiones sistemáticas con o sin metaanálisis). RESULTADOS: Se realizó una búsqueda de la literatura con respecto a la eficacia y seguridad de afatinib, en comparación con la quimioterapia, en pacientes adultos con CPCNP avanzado, con mutaciones activadoras del gen del EGFR, con contraindicación a erlotinib por hipersensibilidad. Dado que no se identificaron estudios en una población específica de pacientes con contraindicación a erlotinib, se procedió a revisar la evidencia para la población general de pacientes con CPCNP avanzado, con mutaciones activadoras del gen del EGFR. CONCLUSIONES: Dado que no se identificaron estudios en la población específica de pacientes con contraindicación a erlotinib, se procedió a revisar la evidencia para la población general de pacientes con CPCNP avanzado, con mutaciones activadoras del gen del receptor del factor de crecimiento epidérmico. En líneas generales, todas las GPC y ETS basaron sus recomendaciones y/o conclusiones en los resultados de los estudios LUX-Lung 3 y/o LUX-Lung 6. La evidencia procedente de los estudios LUX-Lung 3 y LUX-Lung 6 muestra que afatinib comparado con la quimioterapia ofrece un beneficio clínico en términos de una mayor sobrevida global (aproximadamente 11 meses adicionales) en los pacientes con CPCNP metastásico, ECOG 0-1 y mutaciones del EGFR tipo Del19, sin tratamiento previo. Además, afatinib tuvo un perfil de seguridad similar al de la quimioterapia con cisplatino más pemetrexed y un mejor perfil de seguridad que la quimioterapia con gemcitabina más cisplatino, en términos de EA severos, EA serios y discontinuación debido a EA. A diferencia de las GPC identificadas, que recomendaron el uso de afatinib en la población general de pacientes con CPCNP y mutaciones positivas del EGFR, esta evaluación de la evidencia identificó que los pacientes con mutaciones Del19 serían el subgrupo con mayor probabilidad de beneficiarse del tratamiento con afatinib. Por otro lado, no se identificó evidencia directa que sustente el uso de afatinib en el grupo de pacientes previamente tratados. Sin embargo, tal como se menciona en el Dictamen Preliminar de Evaluación de Tecnología Sanitaria N° 041-SDEPFyOTSDETS-IETSI-2019: Eficacia y Seguridad de erlotinib en pacientes adultos con CPCNP, metastásico o irresecable, con mutación del gen del EGFR, tras fallo a al menos una línea de quimioterapia, se valora que la evidencia del uso de afatinib en el contexto de primera línea puede ser extrapolada al grupo de pacientes que han sido previamente tratados con quimioterapia sistémica y que han experimentado hipersensibilidad severa a erlotinib. Adicionalmente, es importante analizar el contexto de intercambio de TKI (de erlotinib a afatinib) debido a EA cutáneos severos como resultado de uma hipersensibilidad a erlotinib (contraindicación de uso) en pacientes con CPCNP avanzado y mutación del EGFR, ya que es el grupo específico de pacientes en quienes se propone el uso de afatinib en la institución. Así, si bien la evidencia sobre el intercambio de TKI debido a EA es limitada, algunas series de casos han sugerido que esta aproximación proporciona un efecto beneficioso en pacientes con CPCNP avanzado y mutaciones del EGFR. Además, el intercambio de erlotinib a afatinib podría justificarse biológicamente dada las diferencias en las estructuras químicas de erlotinib y afatinib, que podrían influir en los EA asociados con estos medicamentos. De este modo, teniendo en cuenta que los pacientes que recibirían un segundo TKI tendrían que haber demostrado no tener una mutación resistente a TKI, se estima que los pacientes que discontinúan el tratamiento con erlotinib debido a hipersensibilidad severa aún podrían beneficiarse de "cambiar" a un segundo TKI (afatinib). Con ello, y considerando la experiencia de uso de TKI a nivel institucional y la opinión favorable por parte de los médicos especialistas de la institución, el equipo evaluador del IETSI encuentra suficientes argumentos técnicos para aprobar el uso de afatinib en pacientes adultos con CPCNP avanzado, con mutaciones activadoras del gen del EGFR (Del19), con contraindicación a erlotinib por hipersensibilidad. Por lo expuesto, el IETSI aprueba el uso de afatinib en pacientes adultos con CPCNP avanzado, con mutaciones activadoras del gen del receptor del factor de crecimiento epidérmico, con contraindicación a erlotinib por hipersensibilidad, según lo establecido en el Anexo N° 1. La vigencia del presente dictamen preliminar es de un año a partir de la fecha de publicación. Así, la continuación de dicha aprobación estará sujeta a los resultados obtenidos de los pacientes que reciban este tratamiento, a los reportes de seguridad que puedan surgir durante farmacovigilancia activa y nueva evidencia que pueda surgir en el tiempo.

Development of an in vitro high content imaging assay for quantitative assessment of CAR-dependent mouse, rat, and human primary hepatocyte proliferation.

Rodent liver tumors promoted by constitutive androstane receptor (CAR) activation are known to be mediated by key events that include CAR-dependent gene expression and hepatocellular proliferation. Here, an in vitro high content imaging based assay was developed for quantitative assessment of nascent DNA synthesis in primary hepatocyte cultures from mouse, rat, and human species. Detection of DNA synthesis was performed using direct DNA labeling with the nucleoside analog 5-ethynyl-2'-deoxyuridine (EdU). The assay was multiplexed to enable direct quantitation of DNA synthesis, cytotoxicity, and cell count endpoints. An optimized defined medium cocktail was developed to sensitize hepatocytes to cell cycle progression. The baseline EdU response to defined medium was greatest for mouse, followed by rat, and then human. Hepatocytes from all three species demonstrated CAR activation in response to the CAR agonists TCPOBOP, CITCO, and phenobarbital based on increased gene expression for Cyp2b isoforms. When evaluated for a proliferation phenotype, TCPOBOP and CITCO exhibited significant dose-dependent increases in frequency of EdU labeling in mouse and rat hepatocytes that was not observed in hepatocytes from three human donors. The observed species differences are consistent with CAR activators inducing a proliferative response in rodents, a key event in the liver tumor mode of action that is not observed in humans.

Multiple platform assessment of the EGF dependent transcriptome by microarray and deep tag sequencing analysis.

BACKGROUND: Epidermal Growth Factor (EGF) is a key regulatory growth factor activating many processes relevant to normal development and disease, affecting cell proliferation and survival. Here we use a combined approach to study the EGF dependent transcriptome of HeLa cells by using multiple long oligonucleotide based microarray platforms (from Agilent, Operon, and Illumina) in combination with digital gene expression profiling (DGE) with the Illumina Genome Analyzer. RESULTS: By applying a procedure for cross-platform data meta-analysis based on RankProd and GlobalAncova tests, we establish a well validated gene set with transcript levels altered after EGF treatment. We use this robust gene list to build higher order networks of gene interaction by interconnecting associated networks, supporting and extending the important role of the EGF signaling pathway in cancer. In addition, we find an entirely new set of genes previously unrelated to the currently accepted EGF associated cellular functions. CONCLUSIONS: We propose that the use of global genomic cross-validation derived from high content technologies (microarrays or deep sequencing) can be used to generate more reliable datasets. This approach should help to improve the confidence of downstream in silico functional inference analyses based on high content data.

Assessment of redox changes to hydrogen peroxide-sensitive proteins during EGF signaling.

Hydrogen peroxide acts as a second messenger in growth factor signaling where it can oxidize and modify the function of redox-sensitive proteins. While selective thiol oxidation has been measured, there has been no global assessment of protein oxidation following growth factor activation. Significant changes to the abundant and widely distributed redox sensitive thiol proteins were observed in A431 epidermoid carcinoma cells exposed to hydrogen peroxide, but no changes were observed following treatment with epidermal growth factor (EGF). This included members of the peroxiredoxin family, which were also monitored in the presence of the thioredoxin reductase inhibitor auranofin to limit their capacity to recycle to the reduced form. We conclude that widespread thiol oxidation does not occur in cells during EGF signaling, and that hydrogen peroxide must act in a highly localized or selective manner.

Investigating differential dynamics of the MAPK signaling cascade using a multi-parametric global sensitivity analysis.

Cell growth critically depends on signalling pathways whose regulation is the focus of intense research. Without utilizing a priori knowledge of the relative importance of pathway components, we have applied in silico computational methods to the EGF-induced MAPK cascade. Specifically, we systematically perturbed the entire parameter space, including initial conditions, using a Monte Carlo approach, and investigate which protein components or kinetic reaction steps contribute to the differentiation of ERK responses. The model, based on previous work by Brightman and Fell (2000), is composed of 28 reactions, 27 protein molecules, and 48 parameters from both mass action and Michaelis-Menten kinetics. Our multi-parametric systems analysis confirms that Raf inactivation is one of the key steps regulating ERK responses to be either transient or sustained. Furthermore, the results of amplitude-differential ERK phosphorylations within the transient case are mainly attributed to the balance between activation and inactivation of Ras while duration-differential ERK responses for the sustained case are, in addition to Ras, markedly affected by dephospho-/phosphorylation of both MEK and ERK. Our sub-module perturbations showed that MEK and ERK's contribution to this differential ERK activation originates from fluctuations in intermediate pathway module components such as Ras and Raf, implicating a cooperative regulatory mode among the key components. The initial protein concentrations of corresponding reactions such as Ras, GAP, and Raf also influence the distinct signalling outputs of ERK activation. We then compare these results with those obtained from a single-parametric perturbation approach using an overall state sensitivity (OSS) analysis. The OSS findings indicate a more pronounced role of ERK's inhibitory feedback effect on catalysing the dissociation of the SOS complex. Both approaches reveal the presence of multiple specific reactions involved in the distinct dynamics of ERK responses and the cell fate decisions they trigger. This work adds a mechanistic insight of the contribution of key pathway components, thus may support the identification of biomarkers for pharmaceutical drug discovery processes.

Decision tree modeling predicts effects of inhibiting contractility signaling on cell motility.

BACKGROUND: Computational models of cell signaling networks typically are aimed at capturing dynamics of molecular components to derive quantitative insights from prior experimental data, and to make predictions concerning altered dynamics under different conditions. However, signaling network models have rarely been used to predict how cell phenotypic behaviors result from the integrated operation of these networks. We recently developed a decision tree model for how EGF-induced fibroblast cell motility across two-dimensional fibronectin-coated surfaces depends on the integrated activation status of five key signaling nodes, including a proximal regulator of transcellular contractile force generation, MLC (myosin light chain) [Hautaniemi et al, Bioinformatics 21: 2027 {2005}], but we have not previously attempted predictions of new experimental effects from this model. RESULTS: In this new work, we construct an improved decision tree model for the combined influence of EGF and fibronectin on fibroblast cell migration based on a wider spectrum of experimental protein signaling and cell motility measurements, and directly test a significant and non-intuitive a priori prediction for the outcome of a targeted molecular intervention into the signaling network: that partially reducing activation of MLC would increase cell motility on moderately adhesive surfaces. This prediction was indeed confirmed experimentally: partial inhibition of the activating MLC kinase (MLCK) upstream using the pharmacologic agent ML-7 resulted in increased motility of NR6 fibroblasts. We further extended this exciting finding by showing that partial reduction of MLC activation similarly enhanced the transmigration of the human breast carcinoma cell line MDA-213 through a Matrigel barrier. CONCLUSION: These findings specifically highlight a central regulatory role for transcellular contractility in governing cell motility, while at the same time demonstrating the value of a decision tree approach to a systems "signal-response" model in discerning non-intuitive behavior arising from integrated operation a cell signaling network.

Growth factor-induced MAPK network topology shapes Erk response determining PC-12 cell fate.

The mitogen-activated protein kinase (MAPK) network is a conserved signalling module that regulates cell fate by transducing a myriad of growth-factor signals. The ability of this network to coordinate and process a variety of inputs from different growth-factor receptors into specific biological responses is, however, still not understood. We investigated how the MAPK network brings about signal specificity in PC-12 cells, a model for neuronal differentiation. Reverse engineering by modular-response analysis uncovered topological differences in the MAPK core network dependent on whether cells were activated with epidermal or neuronal growth factor (EGF or NGF). On EGF stimulation, the network exhibited negative feedback only, whereas a positive feedback was apparent on NGF stimulation. The latter allows for bi-stable Erk activation dynamics, which were indeed observed. By rewiring these regulatory feedbacks, we were able to reverse the specific cell responses to EGF and NGF. These results show that growth factor context determines the topology of the MAPK signalling network and that the resulting dynamics govern cell fate.

C-fos assessment as a marker of anti-epidermal growth factor receptor effect.

Factors predicting sensitivity to epidermal growth factor receptor (EGFR) blockade are largely unknown and new strategies are being sought to individualize cancer therapy. This study evaluated the variation in the expression of the early response gene c-fos as a distal effect of EGFR inhibition and its relationship to antitumor effects. The growth-inhibitory and c-fos-modulating effects of gefitinib and erlotinib in human cancer cell lines (A431, CAL27, HN11, HuCCT1, and Hep2) were determined. Next, these cell lines were xenografted in mice and treated for 14 days with gefitinib (A431 and HuCCT1) or erlotinib (CAL27, HN11, and Hep2). Fine needle aspiration biopsy of tumors was done at baseline and after 14 days of therapy for c-fos assessment. In addition, we tested the feasibility of analyzing this marker in five paired tumor samples from a clinical trial of gefitinib in patients with solid tumors. In culture, gefitinib and erlotinib decreased c-fos mRNA levels in the susceptible cell lines A431, CAL27, and HN11; however, both drugs failed to achieve c-fos inhibition in resistant cells. Gefitinib or erlotinib abrogated the increase in c-fos expression in vivo in EGFR-sensitive A431, CAL27, and HN11 tumors but not in resistant strains. Ex vivo evaluation was feasible and predicted in vivo effects. The feasibility study in paired human tumor biopsies showed that this biomarker can be reliably measured in clinical materials. In summary, variations in c-fos expression reflect the pharmacologic actions of EGFR inhibitors in in vitro and in vivo models.

Galectin-1 augments Ras activation and diverts Ras signals to Raf-1 at the expense of phosphoinositide 3-kinase.

Ras proteins activate diverse effector molecules. Depending on the cellular context, Ras activation may have different biological consequences: induction of cell proliferation, senescence, survival, or death. Augmentation and selective activation of particular effector molecules may underlie various Ras actions. In fact, Ras effector-loop mutants interacting with distinctive effectors provide evidence for such selectivity. Interactions of active Ras with escort proteins, such as galectin-1, could also direct Ras selectivity. Here we show that in comparison with Ras transfectants, H-Ras/galectin-1 or K-Ras4B/galectin-1 co-transfectants exhibit enhanced and prolonged epidermal growth factor (EGF)-stimulated increases in Ras-GTP, Raf-1 activity, and active extracellular signal-regulated kinase. Galectin-1 antisense RNA inhibited these EGF responses. Conversely, Ras and galectin-1 co-transfection inhibited the EGF-stimulated increase in phosphoinositide 3-kinase (PI3K) activity. Galectin-1 transfection also inhibited Ras(G12V)-induced PI3K but not Raf-1 activity. Galectin-1 co-immunoprecipitated with Ras(G12V) or with Ras(G12V/T35S) that activate Raf-1 but not with Ras(G12V/Y40C) that activates PI3K. Thus, galectin-1 binds active Ras and diverts its signal to Raf-1 at the expense of PI3K. This demonstrates a novel mechanism controlling the duration and selectivity of the Ras signal. Ras gains selectivity when it is associated with galectin-1, mimicking the selectivity of Ras(T35S), which activates Raf-1 but not PI3K.

Assessment of growth factor effects on post-thaw development of cryopreserved mouse morulae to the blastocyst stage.

The objective of this study was to assess the influence of specific factors on post-thaw development of mouse cryopreserved morulae. Thawed morulae (n = 206) were randomly distributed between 10 treatment groups: medium alone control (CT), Vero (VR) cells, leukaemia inhibitory factor (1 ng/ml), interleukin-6 (1 ng/ml), transforming growth factor (TGF) alpha (2 ng/ml), epidermal growth factor (EGF) (4 ng/ml), platelet-derived growth factor (1 ng/ml), insulin-like growth factor (IGF)-I (30 ng/ml), IGF-II (1 ng/ml) and TGFbeta (2 ng/ml). At 4, 8, 20, 30 and 48 h, a digitized image of each thawed embryo was captured and stored for later analysis. The following parameters were examined: blastocoel formation, blastocyst expansion, zona thickness and hatching. At termination of the experiment, cell number per embryo was determined by bisbenzimide staining. When contrasted to the medium alone control, co-culture consistently accelerated the development of frozen-thawed morulae to the hatched blastocyst stage, allowing embryos to recover rapidly from any damage sustained during the cryopreservation process. While no single growth factor/cytokine was able to completely mimic the results achieved with co-culture, all of the growth factors impacted positively on at least one of the morphological parameters studied. Cell proliferation was significantly stimulated by just 48 h exposure to growth factors, either through co-culture or by direct media supplementation. Co-culture again yielded the best results with a mean cell count of 217 +/- 76 cells per blastocyst as compared with 131 +/- 36 in control medium alone. Amongst the factors tested, IGF-I, IGF-II and EGF had the greatest impact, with mean cell counts of 172 +/- 50, 168 +/- 50 and 179 +/- 55 respectively. Whereas only 5% of CT embryos developed to blastocysts with > 200 cells, 51% of thawed embryos placed on co-culture monolayers and 25-32% of embryos cultured with IGF-I, IGF-II or EGF had > 200 cells. This study for the first time systematically describes the effect of culture regimen and growth factor additives on the post-thaw development of cryopreserved embryos.

In vivo and in vitro assessment of mitogen activated protein kinase involvement during quail secondary palate formation.

Spatiotemporally regulated cell proliferation and differentiation are crucial for the successful completion of morphogenesis of the vertebrate secondary palate. An understanding of the mechanisms by which these cellular phenomena are regulated during palate development involves the identification of the various signal transduction pathways. In the present study, the presence and activation of mitogen-activated protein (MAP) kinases were investigated during the development of quail secondary palate. The palatal shelves were dissected on days 5-9 of incubation, homogenized, and centrifuged, after which the samples were separated by anion exchange fast protein liquid chromatography. The fractions were analyzed for myelin basic protein (MBP) phosphorylation. In addition, primary cultures of quail palate mesenchymal cells (QPMCs) were treated with epidermal growth factor (EGF) and prepared for MBP phosphorylation assays. A temporally regulated pattern of phosphotransferase activity, characterized by a three-fold increase in phosphotransferase activity toward MBP between days 5 and 8 of incubation, was observed during quail palate development. Western blotting, using MAP kinase antibodies, demonstrated the presence of a 42-kDa isoform between days 5 and 9 of incubation, during which the level of protein remained constant. Antityrosine immunoblotting with 4G10 also detected a 42-kDa protein. Phosphotransferase assays, using either a MAP kinase-specific substrate peptide (S5) or a protein kinase C inhibitor (R3), further confirmed the presence of a MAP kinase in the developing palate of quail. Because diverse biological processes occur concurrently during in vivo palate morphogenesis, the involvement of MAP kinase was explored further in primary cell culture. The data showed that EGF stimulated proliferation and activated 42-kDa MAP kinase in QPMCs. It is suggested that MAP kinase cascade may be involved in growth factor-regulated cell proliferation during morphogenesis of quail secondary palate.

A minimal model for calcium signal generated by tyrosine kinase and G protein linked receptors; a stochastic computer simulation with CALSIM.

A software was designed to simulate the calcium signal following hormone or growth factor stimulation in epithelial cells. The software written in C runs on a PC under Windows environment. It is based on a Markov process where the dynamic of the system is characterised by phenomenological transition probabilities. Moreover a minimal model is proposed to analyse the role of plasma channels and IP3 receptors, together with the opposite action of the CaATPase pumps, in the cytosolic and endoplasmic reticulum (ER) calcium signal control. The simulation is applied on the calcium response following stimulation by carbacol (protein G coupled receptors) or epidermal growth factor (tyrosine kinase type receptors) in A431 epithelial cells. The experimental calcium signals can be grouped in three classes; a spike and a return to the basal level (signal A), a spike and a decrease to a plateau level (signal B) or a slow increase to a plateau (signal C). Epidermal growth factor induces signal A and B while carbacol gives signal B and C. When a 'pseudo' steady state is reached oscillations occur. Computer simulations show that signal A can result from the activation of IP3 receptors while signal C would result from the activation of the plasma channels; signal B appears as the additive contribution of both channels, while oscillations are compatible with a calcium induced calcium release mechanism. Simulations suggest that the calcium dynamic in the ER is a mirror of cytosolic calcium but that a simple way to produce similar calcium elevation in these two compartments is to activate plasma channels. Implications of such a mechanism is discussed.

Assessment of in vitro growth potential of hepatocytes expressing hepatocyte growth factor in an autocrine fashion.

We recently developed transgenic mice expressing hepatocyte growth factor (HGF) specific to hepatocytes. Hepatocytes of HGF transgenic mice showed a 2-fold increase of DNA labeling indices in vivo compared with those of wild type mice. To assess in vitro growth potential of hepatocytes from HGF transgenic mice, we studied the effects of epidermal growth factor (EGF), insulin or transforming growth factor beta (TGF beta) on DNA synthesis of hepatocytes derived from HGF transgenic or wild type mice, respectively. We found that DNA synthesis of hepatocytes from HGF transgenic mice was significantly enhanced, compared with that from wild type mice, respectively, and that its effect was additive with EGF or insulin. Further, growth-inhibitory effects of TGF beta on hepatocytes was greatly depressed in transgenic mice-derived hepatocytes, compared with that in wild type hepatocytes. These data suggest that the autocrine action of HGF is a potent stimulus for hepatocyte growth, and stress its importance as regulator of liver regeneration.

Generation of somatic cell hybrids capable of proliferating and secreting human monoclonal antibody without any growth factor supplements.

A novel cell line called Trioma, which can proliferate and secrete a human monoclonal antibody in the basal medium, was established. Trioma was generated by somatic cell hybridization with human x human hybridoma and A431c, which is a cell line able to grow autonomously in the basal medium. A Trioma called TriH8 has been kept growing in the DMEM/F-12 medium for over 1 year and stably producing stomach cancer-reactive human IgM into culture medium at 10 micrograms/ml. TriH8 has a characteristic cytological phenotype, that is, to diminish cell growth in the presence of epidermal growth factor.

Assessment of epidermal growth factor in the healing process of clean full-thickness skin wounds.

Epidermal growth factor is a potent stimulant of epithelialization. However, the usefulness of topical applications of epidermal growth factor in accelerating wound healing in full-thickness skin wounds with a large panniculus adiposus has not been clear. Four full-thickness skin incisions were made in the back of 10 female pigs that treated twice a day for 14 days with 2 ml of epidermal growth factor (300 ng/ml) or 2 ml of Ringer's lactate solution in a single-blind, randomized fashion. Two pigs received only epidermal growth factor, two pigs received only Ringer's lactate solution, and six pigs were treated with both solutions. The original skin plug was weighed to ensure similarity of groups. Photographs and measurements of each incision were taken every 7 days. The mean surface areas of the incisions treated with epidermal growth factor were 8.45, 7.50, and 2.30 cm2; in the incisions treated with Ringer's lactate solution the measurements were 8.42, 8.16, and 2.37 cm2 on observation days 1, 7, and 14, respectively. Although a trend toward a faster healing rate was noted in the incisions treated with epidermal growth factor, this difference was not statistically significant. With the doses and the time interval used between treatments, minimal benefit was obtained with epidermal growth factor when compared with Ringer's lactate solution.

Angiogenesis: quantitative assessment by the chick chorioallantoic membrane assay.

The aim of the present work was to improve quantitative assessment of angiogenesis by chick chorioallantoic membrane (CAM) assay based on measurement of DNA synthesis. Following incubation of [3H]thymidine (3H-T) with CAM in vivo, incorporation of 3H-T to DNA fraction was expressed as percent of total 3H-T present in the initial homogenate of CAM, regardless of CAM weight and full recovery of applied radioactivity. The assay required simple, partial isolation of DNA to remove traces of free or unspecifically bound 3H-T. These modifications gave a reproducible assay with adequate precision (10-20%). DNA content of CAM did not change between 10-15 days of embryo development and growth of CAM was completed on day 11. 10 to 12-day old CAMs were used for evaluation of the assay. Using a qualitative approach (visual scoring), tissues of several tumors were implanted on CAM. Extracts of tumors that produced the highest score stimulated DNA synthesis in CAM. A similar effect was induced by EGF while cytostatics inhibited DNA synthesis in CAM. Since stimulation of angiogenesis is not a cell type-specific phenomenon, the assay in the present modification should aid the studies on angiogenic factors. With the help of this assay the angiogenic activity of adenocarcinoma of human endometrium was described.

In vitro assessment of keratinocyte aging.

In vitro aging models are based on the observation that normal cells in culture have a finite lifespan and eventually cease to proliferate under conditions that initially support excellent growth. Recent assessment of the aging process in keratinocytes, made possible by improved tissue-culture techniques, have confirmed prior findings with fetal and adult fibroblasts and have permitted investigation into the mechanism of in vitro senescence. Early-passage newborn human keratinocytes maintained in a serum-free system were found to proliferate more rapidly than early-passage adult keratinocytes maintained under identical conditions, and they were also found to have far steeper dose-response curves for a potent hypothalamus-derived mitogen keratinocyte growth factor (KGF), as well as for KGF/EGF in combination, with a more than 200-fold increase in cell number, total protein, and colony size over the tested range of concentrations, as opposed to a less than 75-fold increase for adult keratinocytes in these parameters. These results support the hypothesis that the age-associated decrease for keratinocyte proliferation in vitro may be due to progressive loss of mitogenic responsiveness. Unrecognized changes in proliferative rate and growth-factor requirements related to age of the tissue donor may complicate interpretation of studies addressing other aspects of keratinocyte biology.