At one site (#10), three different batches of MTRRM (see E-TABM-16), were labeled with two different kits (Enzo and Affymetrix) and hybridized to two different Affymetrix Arrays (RAE230A and RAE230_2).
Use of diagnostic accuracy as a metric for evaluating laboratory proficiency with microarray assays using mixed-tissue RNA reference samples.
Sex, Age
View SamplesPancreatic cancers (PCs) are highly metastatic with poor prognosis, mainly due to delayed detection. We hypothesized that intercellular communication is critical for metastatic progression. Here, we show that PC-derived exosomes induce liver pre-metastatic niche formation in naïve mice and consequently increase liver metastatic burden. Uptake of PC-derived exosomes by Kupffer cells caused transforming growth factor ß secretion and upregulation of fibronectin production by hepatic stellate cells. This fibrotic microenvironment enhanced recruitment of bone marrow-derived macrophages. We found that macrophage migration inhibitory factor (MIF) was highly expressed in PC-derived exosomes, and its blockade prevented liver pre-metastatic niche formation and metastasis. Compared to patients whose pancreatic tumors did not progress, MIF was markedly higher in exosomes from stage I PC patients who later developed liver metastasis. These findings suggest that exosomal MIF primes the liver for metastasis and may be a prognostic marker for the development of PC liver metastasis. Overall design: Normal pancreas and Pancreatic cancer exosomes education of human von Kupffer cells in vitro
Pancreatic cancer exosomes initiate pre-metastatic niche formation in the liver.
No sample metadata fields
View SamplesPilocytic astrocytoma is the most common type of brain tumor in pediatric population, generally connected with favorable prognosis, although recurrences or dissemination sometimes are also observed. For tumors originating in supra- or infratentorial location different molecular background was suggested but plausible correlations between transcriptional profile and radiological features and/or clinical course are still undefined. The purpose of this study was to identify gene expression profiles related to the most frequent locations of this tumor, subtypes based on various radiological features and clinical pattern of the disease. According to the radiological features presented on MRI, all cases were divided into four subtypes: solid or mainly solid, cystic with an enhancing cyst wall, cystic with a non-enhancing cyst wall and solid with central necrosis. Bioinformatic analyses showed that gene expression profile of pilocytic astrocytoma highly depends on the tumor location. Most prominent differences were noted for IRX2, PAX3, CXCL14, LHX2, SIX6, CNTN1 and SIX1 genes expression which could distinguish pilocytic astrocytomas of different location even within supratentorial region. Analysis of the genes potentially associated between radiological features showed much weaker transcriptome differences. Single genes showed association with the tendency to progression. Here we showed that pilocytic astrocytomas of three different locations could be precisely differentiated on the basis of gene expression level but their transcriptional profiles did not strongly reflect the radiological appearance of the tumor or the course of the disease.
Transcriptional profiles of pilocytic astrocytoma are related to their three different locations, but not to radiological tumor features.
Sex, Age, Specimen part, Disease
View SamplesStephen Paget first proposed, in 1889, that organ distribution of metastases is a non-random event, yet metastatic organotropism remains one of the greatest mysteries in cancer biology. Here, we demonstrate that exosomes released by lung-, liver- and brain-tropic tumor cells fuse preferentially with resident cells at their predicted destination, such as fibroblasts and epithelial cells in the lung, Kupffer cells in the liver, and endothelial cells in the brain. We found that exosome homing to organ-specific cell types prepares the pre-metastatic niche and that treatment with exosomes derived from lung tropic models can redirect metastasis to the lung. Proteomic profiling of exosomes revealed distinct integrin expression patterns associated with each organ-specific metastasis. Whereas exosomal integrins a6ß4 and a6ß1 were associated with lung metastasis, exosomal integrins avß5 and avß3 were linked with liver and brain metastases, respectively. Targeting a6ß4 and avß5 integrins decreased exosome uptake and metastasis in the lung and liver, respectively. Importantly, we demonstrate that exosome uptake activates a cell-specific subset of S100 family genes, known to support cell migration and niche formation. Finally, our clinical data indicate that integrin-expression profiles in circulating plasma exosomes from cancer patients could be used to predict organ-specific metastasis. Overall design: Education of human von Kupffer cells in vitro with human pancreatic cancer exosomes
Tumour exosome integrins determine organotropic metastasis.
No sample metadata fields
View SamplesWe have analyzed, using DNA microarrays, putative differences in gene-expression level between hereditary BRCA1 mutation-linked and sporadic breast cancer. Our results show that a previously reported marked difference between BRCA1-mutation linked and sporadic breast cancer was probably due to uneven stratification of samples with different ER status and basal-like versus luminal-like subtype. We observed that apparent difference between BRCA1-linked and other types of breast cancer found in univariate analysis was diminished when data were corrected for ER status and molecular subtype in multivariate analyses. In fact, the difference in gene expression pattern of BRCA1-mutated and sporadic cancer is very discrete. These conclusions were supported by the results of Q-PCR validation. We also found that BRCA1 gene inactivation due to promoter hypermethylation had similar effect on general gene expression profile as mutation-induced protein truncation. This suggests that in the molecular studies of hereditary breast cancer, BRCA1 gene methylation should be recognized and considered together with gene mutation.
BRCA1-related gene signature in breast cancer: the role of ER status and molecular type.
Age
View SamplesMolecular mechanisms of cell cycle exit are poorly understood. A group of genes required for cell cycle exit and maintenance of cell quiescence in human fibroblasts following serum deprivation has been recently identified. Studies on lymphocytes following growth factor deprivation-induced cell cycle exit have predominantly focused on the initiation of apoptosis. A set of genes involved in lymphocyte quiescence have also been identified among genes highly expressed in resting lymphocytes and down-regulated after cell activation. In our study, proliferating IL-2-dependent human T cells were forced to exit cell cycle by growth factor withdrawal, and their gene expression profiles were examined.
Molecular signature of cell cycle exit induced in human T lymphoblasts by IL-2 withdrawal.
No sample metadata fields
View SamplesThe introduction of microarray techniques to cancer research brought great expectations for finding biomarkers that would improve patients treatment; however, the results of such studies are poorly reproducible and critical analyses of these methods are rare. In this study, we examined global gene expression in 97 ovarian cancer samples. Also, validation of results by quantitative RT-PCR was performed on 30 additional ovarian cancer samples. We carried out a number of systematic analyses in relation to several defined clinicopathological features. The main goal of our study was to delineate the molecular background of ovarian cancer chemoresistance and find biomarkers suitable for prediction of patients prognosis. We found that histological tumor type was the major source of variability in genes expression, except for serous and undifferentiated tumors that showed nearly identical profiles. Analysis of clinical endpoints [tumor response to chemotherapy, overall survival, disease-free survival (DFS)] brought results that were not confirmed by validation either on the same group or on the independent group of patients. CLASP1 was the only gene that was found to be important for DFS in the independent group, whereas in the preceding experiments it showed associations with other clinical endpoints and with BRCA1 gene mutation; thus, it may be worthy of further testing. Our results confirm that histological tumor type may be a strong confounding factor and we conclude that gene expression studies of ovarian carcinomas should be performed on histologically homogeneous groups. Among the reasons of poor reproducibility of statistical results may be the fact that despite relatively large patients group, in some analyses one has to compare small and unequal classes of samples. In addition, arbitrarily performed division of samples into classes compared may not always reflect their true biological diversity. And finally, we think that clinical endpoints of the tumor probably depend on subtle changes in many and, possibly, alternative molecular pathways, and such changes may be difficult to demonstrate.
Gene expression analysis in ovarian cancer - faults and hints from DNA microarray study.
No sample metadata fields
View SamplesTo identify the molecular mechanisms and environmental inducers contributing to reprogramming of hepatocytes into progenitors in HCC context, we used the HepaRG cell line as model.
Inflammatory cytokines promote the retrodifferentiation of tumor-derived hepatocyte-like cells to progenitor cells.
Cell line, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
BRAFV600E-Associated Gene Expression Profile: Early Changes in the Transcriptome, Based on a Transgenic Mouse Model of Papillary Thyroid Carcinoma.
Sex, Age
View SamplesBRAFV600E mutation is the most frequent molecular event in papillary thyroid carcinoma. The relation of this genetic alteration with the factors od poor prognosis has been reported as well as its influence on PTC gene signature. However human material disables distinction of cancer causes from its effect.
BRAFV600E-Associated Gene Expression Profile: Early Changes in the Transcriptome, Based on a Transgenic Mouse Model of Papillary Thyroid Carcinoma.
Sex, Age
View Samples