RESUMEN
In this study, we report coexpression of transforming growth factor-beta (TGF-beta) and interleukin-10 (IL-10) in pancreatic carcinoma tissue associated with significantly elevated levels of both cytokines in the sera of pancreatic carcinoma patients. Using conditioned media (CM) of pancreatic carcinoma cells, we further demonstrate that tumor cell-derived TGF-beta and IL-10 inhibited in an additive fashion both proliferation and the development of Th1-like responses in peripheral blood mononuclear cell (PBMC) preparations derived from normal donors. The antiproliferative and Th1-suppressive activities contained in CM of pancreatic carcinoma cells were due primarily to IL-10 and/or TGF-beta, as shown by the capacity of cytokine-specific neutralizing antibodies to reverse these effects. Finally, as compared to normal controls, PBMC derived from pancreatic carcinoma patients displayed a Th2-like cytokine expression pattern upon activation with either anti-CD3 antibody or Staphylococcus aureus strain Cowan I. Taken together, these results suggest that aberrant production of TGF-beta and IL-10 in pancreatic tumor patients skews T-cell cytokine production patterns in favor of a Th2 immunophenotype.
Asunto(s)
Adenocarcinoma/metabolismo , Interleucina-10/metabolismo , Neoplasias Pancreáticas/metabolismo , Linfocitos T/inmunología , Células TH1/inmunología , Células Th2/inmunología , Factor de Crecimiento Transformador beta/metabolismo , Adenocarcinoma/inmunología , Anciano , Anticuerpos Monoclonales , Medios de Cultivo Condicionados/farmacología , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Inmunofenotipificación , Interferón gamma/antagonistas & inhibidores , Interleucina-10/biosíntesis , Interleucina-10/sangre , Interleucina-12/antagonistas & inhibidores , Células Asesinas Activadas por Linfocinas/inmunología , Masculino , Persona de Mediana Edad , Conductos Pancreáticos/patología , Neoplasias Pancreáticas/inmunología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Crecimiento Transformador beta/biosíntesis , Factor de Crecimiento Transformador beta/sangre , Células Tumorales CultivadasRESUMEN
Cooperation between in vitro exogenous prolactin (PRL), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-3 (IL-3) at an early step of in vitro erythroid differentiation has been shown in a previous study. To gain more insight into the role of PRL in in vivo hematopoiesis, we have now addressed the involvement of endogenous PRL in the growth of hematopoietic progenitors in a bone marrow (BM) stroma environment. The possible modulation of local PRL production by the inflammatory mediator platelet-activating factor (PAF), which is known to be produced by BM cells and to regulate pituitary PRL release, has also been evaluated. Development of burst-forming unit-erythroid (BFU-E) colonies from CD34+ hematopoietic progenitors cultured on a BM stroma cells (BMSC) layer was slightly, but significantly, reduced in the presence of an anti-human PRL antibody. Pretreatment of BMSC with PAF increased the BFU-E colony efficiency of cocultured CD34+ cells, and this effect was completely abrogated by the antiserum. PAF-modulated release of PRL by BMSC was confirmed by an enzyme-linked-immunospot (Elispot) technique. In addition, immunoprecipitation and Western blotting experiments showed two immunoreactive products in the BMSC culture medium. These corresponded to the nonglycosylated (23 kD) and glycosylated (25.5 kD) forms of pituitary PRL that are also expressed by the B-lymphoblastoid cell line IM9-P3. Specific increase of the nonglycosylated form and decrease of the glycosylated form was observed after PAF treatment. Polymerase chain reaction (PCR) amplification of reverse transcribed RNA using PRL-specific primers showed the presence of PRL message in BMSC and IM9-P3 cells. In situ hybridization experiments with a rat PRL cDNA probe cross-reacting with human PRL mRNA confirmed its presence in a small fraction of unstimulated BMSC and in the majority of PAF-stimulated BMSC. The enhancing effect of PAF on PRL-mediated colony formation, PRL release, and mRNA activation was counteracted by pretreating BMSC with the PAF-receptor (R) antagonist WEB 2170. Lastly, responsiveness of BMSC to PAF was substantiated by the presence of the PAF-R mRNA on these cells.
Asunto(s)
Células de la Médula Ósea , Eritropoyesis/fisiología , Células Madre Hematopoyéticas/fisiología , Factor de Activación Plaquetaria/fisiología , Prolactina/fisiología , Células del Estroma/fisiología , Animales , Médula Ósea/fisiología , Técnicas de Cocultivo , Células Madre Hematopoyéticas/citología , Humanos , Interleucina-3/fisiología , Ratas , Células del Estroma/citología , Células Tumorales CultivadasRESUMEN
Activation of the receptor tyrosine kinase c-kit by the kit-ligand, also known as stem cell factor (SCF), is essential to melanocyte and germ cell development and during the early stages of hematopoiesis. Deregulated expression of c-kit has been reported in malignancies affecting these lineages, i.e., myeloid leukemias, melanomas, and germ cell tumors. In addition, c-kit and SCF are coexpressed in some breast and colorectal cancer (CRC) cells, raising the question of whether c-kit serves an autocrine role in normal or malignant epithelial tissues. In this study, we demonstrate that human colorectal carcinomas, but not normal colorectal mucosa cells, coexpress SCF and c-kit in situ. Expression of c-kit was also observed in mucosa adjacent to colorectal tumor tissue. Consistent with a growth-regulatory role of SCF in CRC cells, exogenous SCF stimulated anchorage-dependent and anchorage-independent growth in four out of five CRC cell lines. Exogenous transforming growth factor (TGF)-beta 1 added at nanomolar concentrations to HT-29 CRC cells, which express the type I, II, and III TGF-beta receptors, downregulated c-kit expression to background levels and inhibited c-kit-dependent proliferation. Similarly, TGF-beta 1 inhibited SCF-dependent proliferation of three first-passage CRC cell lines. In summary, expression of the potential autocrine SCF/ c-kit axis is a tumor-associated phenomenon in colorectal cancer that can be suppressed by TGF-beta 1 in TGF-beta-responsive CRC cells.
Asunto(s)
Carcinoma/patología , Neoplasias Colorrectales/patología , Proteínas Proto-Oncogénicas c-kit/fisiología , Factor de Células Madre/fisiología , Factor de Crecimiento Transformador beta/farmacología , Adulto , Anciano , Adhesión Celular , División Celular , Regulación hacia Abajo , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Mucosa Intestinal/metabolismo , Masculino , Persona de Mediana Edad , ARN Mensajero/genética , ARN Neoplásico/genéticaRESUMEN
This paper describes a non-invasive, very inexpensive method of estimating tissue displacements of various origin that is easy and fast to set up. This technique utilizes an inductive proximity sensor (IPS), which is a non-contact length transducer measuring the distance between its probe and a metal target. Its working principle is based on the electromagnetic coupling originating between the sensor probe, a source of high-frequency magnetic field, and the metal target where parasitic currents take place. The linear working range of the IPS model used here is 0.1 to 6 mm probe-target distance, its resolution is about 2 microns. The IPS has been employed on rabbits and humans to measure the displacement of a target glued to the skin of various body areas with respect to the fixed probe of the sensor. Its high resolution, together with an extensive working range, allows the evaluation of numerous physiological events which produce displacements ranging from 2 microns -- to 9 mm, reflecting either tissue volume changes or movements. In particular, an interesting application is to monitor, through volume variations, the extent and the time course of local vascular modifications induced by manoeuvres which elicit changes in vasomotor tone; vascular filling, tissue swelling etc. Therefore, this measure may be considered a 'surface plethysmography' record. In addition, the contractions of skeletal muscles, under either isotonic or isometric conditions, can be estimated through this sensor. This system may therefore find applications for research purposes and practical demonstrations to students.
Asunto(s)
Contracción Muscular , Pletismografía/instrumentación , Pletismografía/métodos , Sistema Vasomotor/fisiología , Animales , Estimulación Eléctrica , Humanos , Flujometría por Láser-Doppler , Músculo Masetero/fisiología , Cuello/inervación , Conejos , Músculos Respiratorios/fisiología , Sistema Nervioso Simpático/fisiologíaRESUMEN
The effect of sympathetic stimulation on the jaw jerk reflex has been studied in precollicular decerebrate rabbits. This reflex was elicited by a downward mandibular movement applied to the lower jaw through a servo controlled puller. Unilateral stimulation of the cervical sympathetic nerve at 10/s consistently induced a decrease in the JJR, i.e. a marked reduction of the EMG activity in the ipsilateral masseter muscle, accompanied by a 30-40% decrease in the reflexly developed force. In these trials EMG of the contralateral muscle, recorded as control, was not significantly affected. Bilateral stimulation of cervical sympathetic nerve strongly reduced or suppressed the EMG activity in both sides and produced a parallel decrease in the developed force which reached values ranging from 12.5% to 37.0% of controls (with an average of 28.9% +/- 8.9, S.D.). The effect of sympathetic stimulation was also tested on the contraction of the masseter muscle elicited by direct electrical stimulation. Sympathetic activation induced a modest increase in both amplitude and duration of muscle twitch, thus showing that the reduction in the reflex response can not be attributed to an action exerted by the adrenergic mediator on the muscular contraction. All these effects were almost completely abolished by the blockade of alpha-adrenergic receptors. They were proved not to be secondary to the sympathetically-induced vasomotor changes. Therefore the marked JJR reduction produced by activation of the sympathetic nervous system is suggested to be due to the sympathetically-induced decrease in neuromuscular spindle sensitivity to muscle length changes, previously reported.