ABSTRACT
The aim of this work was to understand whether the nature of breast cancer cells could modify the nature of the dialog of mesenchymal stem cells (MSCs) with cancer cells. By treating MSCs with the conditioned medium of metastatic Estrogen-receptor (ER)-negative MDA-MB-231, or non-metastatic ER-positive MCF-7 breast cancer cells, we observed that a number of chemokines were produced at higher levels by MSCs treated with MDA-MB-231 conditioned medium (CM). MDA-MB-231 cells were able to induce NF-κB signaling in MSC cells. This was shown by the use of a NF-kB chemical inhibitor or an IκB dominant negative mutant, nuclear translocation of p65 and induction of NF-κB signature. Our results suggest that MDA-MB-231 cells exert their effects on MSCs through the secretion of IL-1ß, that activates MSCs and induces the same chemokines as the MDA-MB-231CM. In addition, inhibition of IL-1ß secretion in the MDA-MB-231 cells reduces the induced production of a panel of chemokines by MSCs, as well the motility of MDA-MB-231 cells. Our data suggest that aggressive breast cancer cells secrete IL-1ß, which increases the production of chemokines by MSCs.
Subject(s)
Breast Neoplasms/metabolism , Chemokines/metabolism , Interleukin-1beta/metabolism , Mesenchymal Stem Cells/metabolism , Paracrine Communication , Tumor Microenvironment , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Cell Line, Tumor , Cell Movement , Chemokines/genetics , Culture Media, Conditioned/metabolism , Female , Gene Expression Regulation, Neoplastic , Humans , I-kappa B Proteins/genetics , I-kappa B Proteins/metabolism , Interleukin-1beta/genetics , Mutation , Neoplasm Invasiveness , RNA Interference , Signal Transduction , Time Factors , Transcription Factor RelA/metabolism , TransfectionABSTRACT
The involvement of the coxsackie and adenovirus receptor (CAR), an adhesion molecule known to be the main determinant of adenovirus transduction of the cells, in cancer is currently under investigation. Recent reports suggest that CAR levels are elevated in breast cancer, and this may have an impact on its use as means of delivery for gene therapy. In this study, we show that estradiol (E(2)) treatment of the estrogen receptor (ER)-positive breast cancer cell MCF-7 increases CAR levels and, in turn, enhances adenoviral transduction. Employing the transfection of CAR promoters in breast cancer cells, we show that this regulation of CAR expression occurs at the transcriptional level. In addition, and by chromatin immunoprecipitation, we have identified a crucial region of CAR promoter that controls E(2) responsiveness of CAR gene through the recruitment of ER. Moreover, utilizing CAR antibodies or CAR silencing by RNA interference repressed the estrogen-dependent growth of breast cancer cells, whereas the stable expression of CAR in MCF-7 or MDA-MB-231 cells led to an increased proliferation. Altogether, our data suggest that CAR is a novel estrogen-responsive gene, which is involved in the E(2)-dependent proliferation of breast cancer cells.
Subject(s)
Adenocarcinoma/pathology , Breast Neoplasms/pathology , Estradiol/pharmacology , Estrogens/physiology , Neoplasm Proteins/physiology , Neoplasms, Hormone-Dependent/pathology , Receptors, Virus/physiology , Adenocarcinoma/metabolism , Adenoviruses, Human/physiology , Antibodies, Monoclonal/pharmacology , Breast Neoplasms/metabolism , Cell Division/drug effects , Cell Line, Tumor/drug effects , Cell Line, Tumor/metabolism , Coxsackie and Adenovirus Receptor-Like Membrane Protein , Estrogen Receptor alpha/drug effects , Estrogen Receptor alpha/genetics , Female , Genes, Reporter , Humans , Mutagenesis, Site-Directed , Neoplasm Proteins/antagonists & inhibitors , Neoplasm Proteins/drug effects , Neoplasm Proteins/genetics , Neoplasms, Hormone-Dependent/metabolism , Promoter Regions, Genetic/drug effects , RNA Interference , RNA, Neoplasm/biosynthesis , RNA, Small Interfering/pharmacology , Receptors, Virus/antagonists & inhibitors , Receptors, Virus/drug effects , Receptors, Virus/genetics , Recombinant Fusion Proteins/physiology , Signal Transduction , Transcription, Genetic , TransfectionABSTRACT
BACKGROUND: Ghrelin targets the arcuate nucleus, from where growth hormone releasing hormone (GHRH) neurones trigger GH secretion. This hypothalamic nucleus also contains neuropeptide Y (NPY) neurons which play a master role in the effect of ghrelin on feeding. Interestingly, connections between NPY and GHRH neurons have been reported, leading to the hypothesis that the GH axis and the feeding circuits might be co-regulated by ghrelin. PRINCIPAL FINDINGS: Here, we show that ghrelin stimulates the firing rate of identified GHRH neurons, in transgenic GHRH-GFP mice. This stimulation is prevented by growth hormone secretagogue receptor-1 antagonism as well as by U-73122, a phospholipase C inhibitor and by calcium channels blockers. The effect of ghrelin does not require synaptic transmission, as it is not antagonized by gamma-aminobutyric acid, glutamate and NPY receptor antagonists. In addition, this hypothalamic effect of ghrelin is independent of somatostatin, the inhibitor of the GH axis, since it is also found in somatostatin knockout mice. Indeed, ghrelin does not modify synaptic currents of GHRH neurons. However, ghrelin exerts a strong and direct depolarizing effect on GHRH neurons, which supports their increased firing rate. CONCLUSION: Thus, GHRH neurons are a specific target for ghrelin within the brain, and not activated secondary to altered activity in feeding circuits. These results support the view that ghrelin related therapeutic approaches could be directed separately towards GH deficiency or feeding disorders.
Subject(s)
Action Potentials/drug effects , Ghrelin/pharmacology , Growth Hormone-Releasing Hormone/metabolism , Neurons/physiology , Animals , Arcuate Nucleus of Hypothalamus/cytology , Calcium Channel Blockers/pharmacology , Calcium Channels/metabolism , Dose-Response Relationship, Drug , Estrenes/pharmacology , Female , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Growth Hormone-Releasing Hormone/genetics , Indoles , Male , Mice , Mice, Transgenic , Neurons/metabolism , Oligopeptides/pharmacology , Patch-Clamp Techniques , Pyrrolidinones/pharmacology , Receptors, Ghrelin/agonists , Tryptophan/analogs & derivatives , Type C Phospholipases/antagonists & inhibitors , Type C Phospholipases/metabolismABSTRACT
Prostate cancer (PCa) represents the second leading cause of death among all cancer types in men in Europe and North America. Among the factors suspected to control PCa, incidence and progression, chemokines, and their receptors are now intensively studied. Chemokines are produced by tumor cells and also by the stromal microenvironment, both in the primary tumor site and in distant metastatic locations. The wide and differential distribution of chemokines and their receptors account for the pleiotropic actions of chemokines in PCa, including the modulation of growth, angiogenesis, invasion, metastasis, and hormone escape. This review will focus on the roles and the mechanisms of action and regulation of chemokines in the different steps of PCa development and will discuss the novel strategies that are currently envisioned to target chemokines in PCa.
