Project description:BackgroundGlioblastoma (GBM) is the most aggressive primary brain tumor. Its cellular composition is very heterogeneous, with cells exhibiting stem-cell characteristics (GSCs) that co-determine therapy resistance and tumor recurrence. Bone Morphogenetic Protein (BMP)-4 promotes astroglial and suppresses oligodendrocyte differentiation in GSCs, processes associated with superior patient prognosis. We characterized variability in cell viability of patient-derived GBM cultures in response to BMP4 and, based on single-cell transcriptome profiling, propose predictive positive and early-response markers for sensitivity to BMP4.MethodsCell viability was assessed in 17 BMP4-treated patient-derived GBM cultures. In two cultures, one highly-sensitive to BMP4 (high therapeutic efficacy) and one with low-sensitivity, response to treatment with BMP4 was characterized. We applied single-cell RNA-sequencing, analyzed the relative abundance of cell clusters, searched for and identified the aforementioned two marker types, and validated these results in all 17 cultures.ResultsHigh variation in cell viability was observed after treatment with BMP4. In three cultures with highest sensitivity for BMP4, a substantial new cell subpopulation formed. These cells displayed decreased cell proliferation and increased apoptosis. Neuronal differentiation was reduced most in cultures with little sensitivity for BMP4. OLIG1/2 levels were found predictive for high sensitivity to BMP4. Activation of ribosomal translation (RPL27A, RPS27) was up-regulated within one day in cultures that were very sensitive to BMP4.ConclusionThe changes in composition of patient-derived GBM cultures obtained after treatment with BMP4 correlate with treatment efficacy. OLIG1/2 expression can predict this efficacy, and upregulation of RPL27A and RPS27 are useful early-response markers.
Project description:BACKGROUND: The aim of this work was to investigate in vitro the putative role of EGR-1 in the growth of glioma cells. EGR-1 expression was examined during the early passages in vitro of 17 primary cell lines grown from 3 grade III and from 14 grade IV malignant astrocytoma explants. The explanted tumors were genetically characterized at the p53, MDM2 and INK4a/ARF loci, and fibronectin expression and growth characteristics were examined. A recombinant adenovirus overexpressing EGR-1 was tested in the primary cell lines. RESULTS: Low levels of EGR-1 protein were found in all primary cultures examined, with lower values present in grade IV tumors and in cultures carrying wild-type copies of p53 gene. The levels of EGR-1 protein were significantly correlated to the amount of intracellular fibronectin, but only in tumors carrying wild-type copies of the p53 gene (R = 0,78, p = 0.0082). Duplication time, plating efficiency, colony formation in agarose, and contact inhibition were also altered in the p53 mutated tumor cultures compared to those carrying wild-type p53. Growth arrest was achieved in both types of tumor within 1-2 weeks following infection with a recombinant adenovirus overexpressing EGR-1 but not with the control adenovirus. CONCLUSIONS: Suppression of EGR-1 is a common event in gliomas and in most cases this is achieved through down-regulation of gene expression. Expression of EGR-1 by recombinant adenovirus infection almost completely abolishes the growth of tumor cells in vitro, regardless of the mutational status of the p53 gene.
Project description:High throughput proteomics profiling provide an unprecedented opportunity for dissecting molecular mechanisms in cancer biology. Here we present deep profiling of whole proteome and phosphoproteome in two high-grade glioma mouse models driven by mutated receptor tyrosine kinase (RTK) oncogenes. Using multiplex isobaric labeling (10-plex TMT) coupled with extensive liquid chromatography and mass spectrometry, we analyzed ~ 12K genes and > 30K phosphosites by extensive mass spectrometry. Systematical reprogramming of the proteome and phosphoproteome were observed in HGG tumors compare to normal cortex.
Project description:Summary: Astrocytomas can be categorized as either low grade or high grade (glioblastoma). Low grade astrocytomas are not generally aggressive tumors whereas glioblastomas are and in turn have a high mortality rate. The purpose of this experiment is to identify genetic differences between the two types. Hypothesis: There will be a difference in RNA expression between high grade and low grade tumors. Specific Aim: To identify genes which make a tumor high grade or low grade Experiment Overall Design: Comparison of 8 high grade and 12 low grade tumors
Project description:Background To identify the spectrum of malignant attributes maintained outside the host environment, we have compared global gene expression in primary breast tumors and matched short-term epithelial cultures. Results In contrast to immortal cell lines, a characteristic 'limited proliferation' phenotype was observed, which included over expressed genes associated with the TGFbeta signal transduction pathway, such as SPARC, LOXL1, RUNX1, and DAPK1. Underlying this profile was the conspicuous absence of hTERT expression and telomerase activity, a significant increase in TGFbeta receptor2, its cognate ligand, and the CDK inhibitor, p21CIP1/WAF1. Concurrently, tumor tissue and primary cultures displayed low transcript levels of proliferation-related genes, such as, TOP2A, ANKT, RAD51, UBE2C, CENPA, RRM2, and PLK. Conclusions Our data demonstrate that commonly used immortal cell lines do not reflect some aspects of tumor biology as closely as primary tumor cell cultures. The gene expression profile of malignant tissue, which is uniquely retained by cells cultured on solid substrates, could facilitate the development and testing of novel molecular targets for breast cancer.
Project description:Mammalian cells were grown as multicellular aggregates (spheroids) in an effort to determine the signaling events required for two cellular transformations states; primary foreskin fibroblasts (HFF-2) and glioblastoma cancer (T98G) cells, to survive at room temperature under oxygen and nutrient-deprived conditions for extended periods of time (2 weeks) and subsequently grown out from the arrested state as adherent monolayers. HFF-2 cells were cultured in DMEM supplemented with 15% fetal bovine serum and 5% carbon dioxide humidified air at 37 degrees C. T98G cells were cultured in EMEM with 10% FBS, 5% non-essential amino acids and 5% carbon dioxide humidified air at 37 degreesC. Monolayers were grown in T-185 flasks to 60% confluency then split into T-185 flasks coated with a 1% agarose mix in a 2:1 media/water ratio. Cells were suspended in 30 ml of supplemented media and grown for 4 days in order to form multicellular spheroids as described previously by our group (J. Cell. Physiol., 206 [2006] 526-536; see GSE1364 and GSE1455 for similar experiments with HEK293 cells). The suspension was removed from the flasks and centrifuged (1500 x g, 2 min) and the media removed. The pellet was returned to the flasks and then placed in vacuum bags (Dri-shield 2000 moisture barrier bag from Surmount Inc., USA; Cat. number 70068), which were sealed immediately under vacuum (Deni Magic Vac, Champion model; Keystone Manufacturing, USA). Vacuum-sealed flasks were stored for 2 weeks (in the dark) at room temperature. Recovery was initiated by removing the flask from the bag and resuspending the spheroids in supplemented media and placing the flasks in a 5% CO2/humidified air incubator maintained at 37 degreesC. Timepoints for transcriptional analysis were monolayer (control), 4 day growth spheroids, 2 week stored spheroids and 7 day growth back to monolayers. There were 67 HFF-2 and 50 T98G genes that exhibited at least a 10-fold change in expression during the course of arrest and recovery. Eleven of these genes were common to both cell lines. While the trends were the same between the two cell lines for genes that were in common, the timing of the responses were clearly different. The primary fibroblasts showed significant gene expression changes during spheroid formation and returned to their initial monolayer state after the two week arrest, whereas the glioblastoma cells exhibited major changes in gene expression during the recovery process. Furthermore, the T98G cells never returned to the monolayer expression levels during the time course of the recovery phase (7 days growth under monolayer conditions). Major differences in the transcriptional data were also found between the cell lines with regards to the putative cellular location of the encoded proteins. Of the genes with significant fold changes (+/- 10-fold) for which location information is available, the primary fibroblasts were significantly enriched in genes encoding extracellular (32%) and membrane-associated (26%) proteins. The glioblastoma cells, on the other hand, had only 17% extracellular and 13% membrane-associated. The expression level trends for all genes above the 10-fold cutoff were as observed for the "in common" genes; HFF-2 genes had returned to monolayer expression levels after 7 days of recovery whereas the T98G line was still exhibiting expression values much different from that of the monolayer control.