Mutation or deletion of Neurofibromin (NF1), an inhibitor of RAS signaling, frequently occurs in epithelial ovarian cancer (EOC), supporting therapies that target downstream RAS effectors, such as the RAF-MEK-ERK pathway. However, no comprehensive studies have been carried out testing the efficacy of MEK inhibition in NF1-deficient EOC. Here, we performed a detailed characterization of MEK inhibition in NF1-deficient EOC cell lines using kinome profiling and RNA sequencing. Our studies showed MEK inhibitors were ineffective at providing durable growth inhibition in NF1-deficient cells due to kinome reprogramming. MEKi-mediated destabilization of FOSL1 resulted in induced expression of RTKs and their downstream RAF and PI3K signaling overcoming MEKi therapy. MEKi synthetic enhancement screens identified BRD2 and BRD4 as integral mediators of the MEKi-induced RTK signatures. Inhibition of BET proteins using BET bromodomain inhibitors (BETi) blocked MEKi-induced RTK reprogramming, indicating BRD2 and BRD4 represent promising therapeutic targets in combination with MEKi to block resistance due to kinome reprogramming in NF1-deficient EOC. Overall design: Examination of the global effects on transcription in response to trametinib (GSK212) in A1847 cells.
Intrinsic Resistance to MEK Inhibition through BET Protein-Mediated Kinome Reprogramming in NF1-Deficient Ovarian Cancer.
Specimen part, Cell line, Treatment, Subject
View Samplesp21-activated kinases (Paks) play an important role in oncogenic signaling pathways, and have therefore been considered as potential therapeutic targets in various cancers. Most studies of Pak function employ loss of function methods such as gene knock-out or knock-down, but these approaches result in loss of both the enzymatic and scaffolding properties of these proteins, and thus may not reflect the effects of small molecule inhibitors that block catalytic function. In this study we use a new transgenic mouse model in which a specific peptide inhibitor of Group I Paks (Pak1, -2, and -3) is conditionally expressed in response to Cre recombinase. Using this model, we show that inhibition of endogenous Pak function impedes the transition of adenoma to carcinoma in an Apc-driven mouse model of colorectal cancer. These effects are mediated by inhibition of Wnt signaling through reduced ß-catenin activity as well as suppression of an epithelial-mesenchymal transition program mediated by miR-200 and Snai1. These results highlight the potential therapeutic role of Pak1 inhibitors in colorectal cancer and suggest new therapeutic strategies in this disease. Overall design: We generated a targeted transgenic mouse carrying a conditionally activated PID allele at the Rosa26 locus, and showed that expression of this allele effectively inhibited the activity of Group I Paks in vivo. To assess the global molecular effects of Pak inhibition in Apc-null CRC cells, we next explored the effect of repressing Pak activity on transcription. Total RNA was extracted from PID+ and PID- cells and RNA-sequencing was preformed, followed by pathway analysis and qPCR validation for selected mRNAs.
Group I Paks are essential for epithelial- mesenchymal transition in an Apc-driven model of colorectal cancer.
Treatment, Subject
View SamplesSmall molecule BET bromodomain inhibitors (BETi) are actively being pursued in clinical trials for the treatment of a variety of cancers, however, the mechanisms of resistance to targeted BET protein inhibitors remain poorly understood. Using a novel mass spectrometry approach that globally measures kinase signaling at the proteomic level, we evaluated the response of the kinome to targeted BET inhibitor treatment in a panel of BRD4-dependent ovarian carcinoma (OC) cell lines. Despite initial inhibitory effects of BETi, OC cells acquired resistance following sustained treatment with the BETi, JQ1. Through application of Multiplexed Inhibitor Beads (MIBs) and mass spectrometry, we demonstrate that BETi resistance is mediated by adaptive kinome reprogramming, where activation of compensatory pro-survival kinase networks overcomes BET protein inhibition. Furthermore, drug combinations blocking these kinases may prevent or delay the development of drug resistance and enhance the efficacy of BET inhibitor therapy. Overall design: RNAseq was employed to identify changes in kinase RNA expression following short term (48h) or chronic (JQ1R) JQ1 treatment in three different ovarian cancer cell lines.
Resistance to BET Bromodomain Inhibitors Is Mediated by Kinome Reprogramming in Ovarian Cancer.
Cell line, Subject
View SamplesCompared the global gene expression profiles of HD- and CON-iPSC-derived neurons
Elucidating the role of the A2A adenosine receptor in neurodegeneration using neurons derived from Huntington's disease iPSCs.
Sex, Age, Specimen part
View SamplesThe study was designed in order to identify genes differentially expressed when glucocorticoid signaling is blocked by a glucocorticoid-receptor antagonist (RU486 mifepristone) in the context of brain inflammation induced by bacterial lipopolysaccharide (LPS). LPS is only able to cause murine brain damage in our experimental conditions upon RU486 pre-treatment. Hence, the study may reveal potential candidate genes to mediate neuroprotection or neurotoxicity. Due to the factorial design of the experiment, RU486 main-effect could be dissociated from the effects resultant of RU486/inflammation interaction. In addition, brain dissection was conducted to verify the effects in the brain side ipsilateral or contralateral to the site of intracerebral LPS infusion.
Genes involved in the balance between neuronal survival and death during inflammation.
Sex, Age, Specimen part
View SamplesWound healing is an essential homeostatic mechanism that maintains the epithelial barrier integrity after tissue damage. Although we know the main events participating in the healing of a wound, many of the underlying molecular mechanisms remain unclear. Genetically amenable systems, such as wound healing in Drosophila imaginal discs, do not model all aspects of the repair process, but allow exploring many unanswered features of the healing response; e.g., which are the signal(s) responsible for initiating tissue remodeling? How is the sealing of the epithelia achieved? Or which are the inhibitory cues that cancel the healing machinery upon completion? Answering these and other questions demands in first place the identification and functional analysis of wound-specific genes. A variety of different microarray analyses of murine and humans have identified characteristic profiles of gene expression at the wound site, however, very few functional studies in healing regulation have been carried out. We developed an experimentally controlled method to culture imaginal discs that allows live imaging and biochemical analysis and is healing-permissive. Employing this approach, we performed a comparative genome-wide profiling between those Drosophila imaginal cells actively involved in healing versus their non-engaged siblings. This lets us identify a set of potential wound-specific genes. Importantly, besides identifying and categorizing new genes, we functionally tested many of their gene products by genetic interference and overexpression in a healing assay. This non-saturated analysis defines a relevant set of new genes whose changes in expression levels are functionally significant for proper tissue repair. There is promise that our newly identified wound-healing genes will guide future work in the more complex mammalian wound response.
Identification and functional analysis of healing regulators in Drosophila.
Specimen part, Treatment
View SamplesUHRF1 (Ubiquitin-like, containing PHD and RING finger domains, 1) recruits DNMT1 to hemimethylated DNA during replication, is essential for maintaining DNA methylation patterns during cell division and is suggested to direct additional repressive epigenetic marks. Uhrf1 mutation in zebrafish results in multiple embryonic defects including failed hepatic outgrowth, but the epigenetic basis of these phenotypes is not known. We find that DNA methylation is the only epigenetic mark that is depleted in uhrf1 mutants and make the surprising finding that despite the reduced organ size in uhrf1 mutants, genes regulating DNA replication and S-phase progression were highly upregulated. Further, there is a striking increase in BrdU incorporation in uhrf1 mutant cells, and they retained BrdU labeling over several days, indicating they are arrested in S-phase. Moreover, some of the label retaining nuclei co-localized with TUNEL positive nuclei, suggesting that arrested cells are responsible for apoptosis. Importantly, dnmt1 mutation phenocopies the S-phase arrest and hepatic outgrowth defects in uhrf1 mutants and Dnmt1 knock-down enhances the uhrf1 hepatic phenotype. Together, these data indicate that DNA hypomethylation is sufficient to generate the uhrf1 mutant phenotype by promoting an S-phase arrest. We thus propose that cell cycle arrest is a mechanism to restrict propagation of epigenetically deranged cells during embryogenesis.
DNA hypomethylation induces a DNA replication-associated cell cycle arrest to block hepatic outgrowth in uhrf1 mutant zebrafish embryos.
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View SamplesReactive oxygen species (ROS) are implicated in tumor transformation by modulating proteins involved in differentiation, proliferation and invasion. In order to identify genes that may support melanoma progression or regression after an antioxidant system (AOS) response, we developed and characterized a human melanoma cell model with different levels of ROS by stably overexpressing the antioxidant enzyme catalase in A375 amelanotic melanoma cells, and whole genome gene expression patterns were analyzed by microarrays.
Reprogramming human A375 amelanotic melanoma cells by catalase overexpression: Upregulation of antioxidant genes correlates with regression of melanoma malignancy and with malignant progression when downregulated.
Specimen part, Cell line
View SamplesMacrophages in tumor microenvironment have been characterized as M1- and M2-polarized subtypes. This study sought to investigate the effects of different macrophage subtypes on the biological behavior and global gene expression profiles of lung cancer cells. Expression microarray and bioinformatics analyses indicated that the different macrophage subtypes mainly regulated genes involved in cell cycle, cytoskeletal remodeling, coagulation, cell adhesion and apoptosis pathways in A549 cells, a pattern that correlated with the altered behavior of A549 cells observed after coculture with macrophage subtypes.
Opposite Effects of M1 and M2 Macrophage Subtypes on Lung Cancer Progression.
Specimen part, Cell line
View SamplesIn order to identify patterns of gene expression associated with biological effects in THP-1 cells induced by F3, we performed a transcriptomic analysis on the THP-1 control and F3-treated THP-1 cells by oligonucleotide microarray
Ganoderma lucidum polysaccharides in human monocytic leukemia cells: from gene expression to network construction.
Cell line
View Samples