Transcription profiling of human PDGF-treated SH-SY5Y cells
ABSTRACT: We conducted a proof-of-concept experiment to explore the possibility of using gene expression-based high throughput screening (GE-HTS) to find inhibitors of a signaling cascade, using platelet derived growth factor receptor (PDGFR) signaling as the example. To define ERK/PDGFR activation signature, we performed gene expression profiling using Affymetrix U133A arrays 0.5-4 hours following PDGF stimulation, thereby identifying those genes whose expression is correlated with PDGFR activity. In order to identify the component of the gene expression signature that was attributable to ERK activation by PDGFR (as opposed to other pathways downstream of PDGFR), we also pretreated the cells will the ERK inhibitors U0126 and PD98059, and repeated the gene expression profiling studies. Experiment Overall Design: To define ERK/PDGFR activation signature, SH-SY5Y cells were grown to confluence and starved overnight in serum-free medium in order to silence any sustained effects from growth factor signaling. Prior to induction with 50ng/ml PDGF, cells were treated with pathway inhibitors 74 mM Apigenin or 50 mM U0126, or with DMSO (carrier) for 60 minutes. Total RNA was isolated 30 minutes after PDGF addition. Experiments were performed in duplicate. The RNA was processed and hybridized with Affymetrix U133A GeneChips.
Project description:Human T98G glioblastoma cells were stimulated with platelet-derived growth factor (PDGF) and analyzed by DNA microarrays, which identified 74 immediate-early gene transcripts. Cells were then treated with inhibitors to identify subsets of genes that are targets of the phosphatidylinositol 3-kinase (PI3K) and MEK/ERK signaling pathways. Four groups of PDGF-induced genes were defined: independent of PI3K and MEK/ERK signaling, dependent on PI3K signaling, dependent on MEK/ERK signaling, and dependent on both pathways. Cells were grown in Minimal Essential Medium (Invitrogen) supplemented with fetal calf serum (10%). For growth factor/inhibitor treatments, cells were incubated in serum-free medium for 72 h, and either left unstimulated, or stimulated for 30 min with human PDGF-BB (50 ng/ml) (Sigma). U0126 (Cell Signaling Technology) and LY294002 (BioMol) were added 60 min prior to PDGF addition. Keywords: other
Project description:The platelet-derived growth factor (PDGF) signaling system contributes to tumor angiogenesis and vascular remodeling. Here, we show PDGF-BB markedly induces erythropoietin (EPO) mRNA and protein expression by targeting the PDGFR-beta+ stromal and perivascular compartments. In mouse tumor models, PDGF-BB-induced EPO promotes tumor growth via two mechanisms: 1) paracrine stimulation of tumor angiogenesis by directly inducing endothelial cell proliferation, migration, sprouting and tube formation; and 2) endocrine stimulation of extramedullary hematopoiesis leading to increased oxygen perfusion and protection against tumor-associated anemia. Similarly, delivery of an adenovirus-PDGF-BB to tumor-free mice markedly increases EPO production and hematopoietic parameters. An EPO blockade specifically attenuates PDGF-BB-induced tumor growth, angiogenesis and hematopoiesis. At the molecular level, we show that the PDGF-BB-PDGFR-beta signaling system activates EPO promoter via in part transcriptional regulation of ATF3 by possible association with c-Jun and SP1. These findings uncover a novel mechanism of PDGF-BB-induced tumor growth, angiogenesis and hematopoiesis. Comparison of S17 stromal cells treated with PDGF-BB for 72h to control
Project description:Anti-PDGF agents are routinely used as a key component in front-line therapy for the treatment of various cancers. However, molecular mechanisms underlying their impact on vascular remodeling in relation to the dose issue remain poorly understood. Here we show that in high PDGF-BB-producing tumors, anti-PDGF drugs significantly inhibited tumor growth and metastasis by preventing pericyte (PC) loss and vascular permeability. Surprisingly, the same anti-PDGF-BB drugs promoted tumor cell dissemination and metastasis in PDGF-BB-low-producing or negative tumors by ablating PCs from tumor vessels. At the molecular level, we show that the PDGFR-β signaling pathway in PCs mediated the opposing effects and persistent exposure of PCs to PDGF-BB led to marked downregulation of PDGFR-β. Inactivation of the PDGFR-β signaling system led to decreased levels of integrin α1β1, resulted in impaired adhesion of PCs to collagen I, IV and laminin, two principal extracellular matrix components in blood vessels for interaction with these integrins. Our data suggest that tumor PDGF-BB levels may serve as an important biomarker for selection of tumor-bearing hosts for beneficial therapy and unsupervised practice of this group of drugs could potentially promote tumor invasion and metastasis. Pericytes were isolated and treated with PDGF-BB or control for 5 days.
Project description:Numerous cytokines have been shown to affect epithelial cell differentiation and proliferation through epithelial-mesenchymal interaction. Growing evidence suggests that platelet-derived growth factor (PDGF) signaling is an important mediator of these interactions. The purpose of this study was to evaluate the effect of PDGF-α on enterocyte turnover in a rat model of short bowel syndrome (SBS). Male rats were divided into four groups: Sham rats underwent bowel transection, Sham-PDGF-α rats underwent bowel transection and were treated with PDGF-α, SBS rats underwent a 75% bowel resection, and SBS-PDGF-α rats underwent bowel resection and were treated with PDGF-α. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. Illumina's Digital Gene Expression (DGE) analysis was used to determine PDGF-related gene expression profiling. PDGF-α and PDGF-α receptor (PDGFR-α) expression was determined using Real Time PCR. Western blotting was used to determine p-ERK, Akt1/2/3, bax and bcl-2 protein levels. SBS rats demonstrated a significant increase in PDGF-α and PDGFR-α expression in jejunum and ileum compared to sham animals. SBS-PDGF-α rats demonstrated a significant increase in bowel and mucosal weight, villus height and crypt depth in jejunum and ileum compared to SBS animals. PDGF-α expression in crypts increased in SBS rats (vs sham) and was accompanied by increased cell proliferation following PDGF-α administration. A significant decrease in cell apoptosis in this group was correlated with lower bax protein levels. In conclusion, in a rat model of SBS, PDGF-α stimulates enterocyte turnover, which is correlated with up-regulated PDGF-α receptor expression in the remaining small intestine. Animals were divided randomly into two experimental groups of 6 rats each. Group A rats underwent bowel transection and re-anastomosis (Sham), Group B animals underwent 75% bowel resection (SBS). Due to the quality of DNA, we performed final analysis from 5 jejunal samples (1 sham and 4 resected rats) and from 7 ileal samples (3 sham and 4 resected rats). Illumina's Digital Gene Expression (DGE) analysis using Illumina Rat Quad BeadChips was used to determine PDGF-related gene expression profiling.
Project description:To explore global molecular changes in smooth muscle in response to PDGFR activation, primary human bladder smooth muscle cells were treated with 1 nM PDGF-BB (hereafter PDGF) for 0, 4 or 24 h. Total RNA were prepared, and analyzed using expression profiling, and subjected to bioinformatic and functional interrogation. To identify molecular signatures of bladder smooth muscle peturbed by PDGF, primary human bladder smooth muscle cells were treated with 1 nM PDGF-BB (hereafter PDGF) for 0, 4 or 24 h.
Project description:Background & Aims: Rapid induction of beta-PDGF receptor (beta-PDGFR) is a core feature of hepatic stellate cell activation, the hallmark of liver fibrogenesis. However, biological consequences of the induction are not well characterized. We aimed to determine the involvement of beta-PDGFR-mediated molecular pathway activation on hepatic stellate cells in liver injury, fibrogenesis, and carcinogenesis in vivo. Methods: Loss and constitutive activation of beta-PDGFR were assessed in mouse models with either a stellate cell-specific beta-PDGFR knockout or the expression of an autoactivating mutation respectively. Liver injury and fibrosis were induced in two mechanistically distinct models: carbontetrachloride (CCl4) treatment and ligation of the common bile duct. Hepatocarcinogenesis with underlying liver injury/fibrosis was assessed by a single dose of diethylnitrosamine (DEN) followed by repeated injections of CCl4. Genome-wide expression profiling was performed isolated stellate cells from these models to determine deregulated pathways. Results: Depletion of beta-PDGFR in hepatic stellate cells led to decreased histological liver injury, serum transaminases, collagen alpha 1(I) and alpha smooth muscle actin expression, and collagen deposition. Stellate cell proliferation was significantly reduced after acute hepatic injury in vivo. In contrast, autoactivation of beta-PDGFR in stellate cells accelerated liver fibrosis, most prominently after 6 weeks of CCl4 induced injury. There was no difference in development of DEN-induced pre-neoplastic loci according to the status of beta-PDGFR. Conclusions: Depletion of beta-PDGFR in hepatic stellate cells attenuated the development of liver injury, fibrosis, and stellate cell proliferation in multiple animal models, whereas the constitutive activation of beta-PDGFR enhanced fibrosis. However, manipulation of beta-PDGFR alone did not reduce development of dysplastic nodules. These findings indicate that titration of receptor beta-PDGFR expression on stellate cells parallels fibrosis and injury, but may not impact the development of hepatic neoplasia alone. Hepatic stellate cells were isolated from liver of beta-PDGFR-wild-type or knockout mice, and treated with beta-PDGF ligand or vehicle control.
Project description:The crizotinib–resistant ALKF1174L mutation arises de novo in neuroblastoma (NB) and is acquired in ALK translocation-driven cancers, lending impetus to the development of novel ALK inhibitors with different modes of action. The diaminopyrimidine TAE684 and its derivative ceritinib (LDK378), which are structurally distinct from crizotinib, are active against NB cells expressing ALKF1174L. Here we demonstrate acquired resistance to TAE684 and LDK378 in ALKF1174L-driven human NB cells that is linked to overexpression and activation of the AXL tyrosine kinase and epithelial-to-mesenchymal transition (EMT). AXL phosphorylation conferred TAE684 resistance to NB cells through upregulated ERK signaling. Inhibition of AXL partly rescued TAE684 resistance, resensitizing these cells to this compound. AXL activation in resistant cells was mediated through increased expression of the active form of its ligand, GAS6, which also served to stabilize the AXL protein. Although ectopic expression of AXL and TWIST2 individually in TAE684-sensitive parental cells led to the elevated expression of mesenchymal markers and invasive capacity, only AXL overexpression induced resistance to TAE684 as well. TAE684-resistant cells showed greater sensitivity to HSP90 inhibition than did their parental counterparts, with downregulation of AXL and AXL-mediated ERK signaling. Our studies indicate that aberrant AXL signaling and development of an EMT phenotype underlie resistance of ALKF1174L-driven NB cells to TAE684 and its derivatives. We suggest that the combination of ALK and AXL or HSP90 inhibitors be considered to delay the emergence of such resistance. In order to understand the molecular mechanisms driving resistance to ALK inhibition in ALK-mutated neuroblatoma, we established cell line models of resistance to TAE684, an ALK inhibitor, by treating SH-SY5Y cells (bearing the ALKF1174L mutation) with increasing concentration of this compound over time. We then performed an analysis of gene expression changes genome wide using Affymetrix U133 Plus 2 arrays, by comparing the TAE684-sensitive parental SH-SY5Y cells to the TAE684-resistant SH-SY5Y cells (named SY5Y-TR1). For that experiment, we analyzed gene expression variations by comparing the parental SH-SY5Y (control sample) to the resistant SY5Y-TR1 cells. So 2 samples were analyzed, with 3 replicates run for each.
Project description:To gain insights into the signalling pathways regulated by Leukocyte common antigen-related protein (LAR), including those that are PDGF-dependent, we have carried out the first systematic analysis of LAR-regulated signal transduction using SILAC-based quantitative proteomic and phosphoproteomic techniques. We have analysed differential phosphorylation between wild-type mouse embryo fibroblasts (MEFs) or MEFS in which the LAR cytoplasmic phosphatase domains had been deleted (LARΔP).
Project description:Aberrant activation of oncogenic kinases is frequently observed in human cancers, but the underlying mechanism and resulting effects on global signaling are incompletely understood. Here, we demonstrate that the oncogenic FIP1L1-PDGFRa kinase exhibits a significantly different signaling pattern compared to PDGFRa wildtype: Interestingly, the conventional strong activation of PI3-kinase- and MAP-kinase- pathways is remarkably shifted towards a prominent activation of STAT factors. This diverging signaling pattern compared to classical PDGF-receptor signaling is partially coupled to the aberrant intracellular location of the oncogene, since membrane targeting of F/PDGFRa restores activation of MAPK- and PI3K-pathway completely. In contrast to the classical cytokine-induced STAT-activation process does STAT activation by F/PDGFR not require Janus kinase activity and does not involve a SH2-domain-mediated binding mechanism. Thus it is conceivable that STAT activation by F/PDGFR could be directly mediated by interaction of STAT factors with the kinase domain itself.
Project description:Platelet-derived growth factor-CC (PDGF-CC) is the third member of the PDGF family discovered after more than two decades of studies on the original members of the family, PDGF-AA and PDGF-BB. The biological function of PDGF-CC remains largely to be explored. We report here a novel finding that PDGF-CC is a potent neuroprotective factor that acts by modulating glycogen synthase kinase (GSK)3beta activity. In several different animal models of neuronal injury, such as axotomy-induced neuronal death, neurotoxin-induced neuronal injury, 6-OHDA-induced Parkinson's dopaminergic neuronal death and ischemia-induced stroke, PDGF-CC protein or gene delivery protected different types of neurons from apoptosis in both the retina and brain. On the other hand, loss-of-function assays using PDGF-C null mice, neutralizing antibody or shRNA showed that PDGF-CC deficiency/inhibition exacerbated neuronal death in different neuronal tissues in vivo. Mechanistically, we revealed that the neuroprotective effect of PDGF-CC was achieved by regulating GSK3beta phosphorylation and expression. Our data demonstrate that PDGF-CC is critically required for neuronal survival, and may potentially be used to treat neurodegenerative diseases. Inhibition of the PDGF-CC/receptor pathway for different clinical purposes should be conducted with caution to preserve normal neuronal functions. PDGF-C deficient mice were bred onto C57BL/6 background for more than six generations and littermates were used. After optic nerve crush (ONC), PDGF-CC protein × 1 µl of active recombinant human PDGF-CC protein 0.5 µg/µl (rhPDGF-CC) was injected into mouse vitreous once a week for two weeks. Seven days after the ONC injury and PDGF-CC protein treatment, retinae were harvested and total RNA isolated using the TRIzol reagent (Invitrogen) followed by the RNeasy Mini kit (Qiagen) purification according to the manufacturer's instructions. Microarray assay was performed using the Mouse-6 Expression BeadChips containing approximately 24,000 annotated mouse transcripts (Illumina Inc). Three biological repeats were included in the microarray assay. Two tailed Student's t-test was used for statistical analysis of gene expression data. Functional grouping of the differentially expressed genes was performed using several different tools including the WebGestalt (http://bioinfo.vanderbilt.edu/webgestalt) and the Ingenuity Pathways Analysis (https://analysis.ingenuity.com/pa/login/login.jsp). The supplementary file 'GSE19207_non-normalized.txt' contains raw data for Samples GSM476021-GSM476026.