Expression data from human melanocyte BRAF kinase activated
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE13827 | GEO | 2008/12/05
SECONDARY ACCESSION(S): PRJNA110499
REPOSITORIES: GEO
Similar Datasets
Project description:Both benign nevi and melanomas exhibit high rates of activating mutations in BRAF kinase, suggesting that this event is important for melanocyte proliferation and melanoma initiation in vivo; however, the precise mechanism of BRAF kinase action in these lesions remains to be elucidated. We have used comprehensive gene expression profiling to evaluate the downstream effectors of activated BRAFV600E kinase in primary human melanocytes and identified a dominant proliferative target gene signature for BRAF kinase in these cells. We used microarrays to detail the global gene expression pattern change induced by the activation of RAS/BRAF/MEK/ERK signaling pathway and identified distinct classes of up-regulated genes during this process. Experiment Overall Design: Primary human melanocytes were isolated from neonatal foreskins. Melanocytes isolated from five individual donors were pooled together in order to reduce genetic variations and transduced by BRAFV600E expressing lentivirus and control virus with MOI 10 respectively. Cells were harvested 5 days following infection and total RNA was extracted and purified by RNeasy kit by following manufacturerâs protocol. RNA quality check, double strand complementry DNA synthesis, hybridization with Human Genome U133 Plus 2.0 Array Chips (Affymetrix Inc. Santa Clara, CA), initial data extraction, normalization using RMAExpress software.
2009-01-13 | E-GEOD-13827 | biostudies-arrayexpress
Project description:Most cancer genomics papers to date have focused on aberrations in genomic DNA and protein-coding transcripts. However, around 50% of transcripts have no coding potential and may exist as non-coding RNA. We performed RNA-seq in BRAFv600e melanoma skin cancer and on melanocytes over-expressing oncogenic BRAF to catalog transcriptome remodeling. We discovered that BRAF regulates expression of 1027 protein coding transcripts, 39 annotated lncRNAs and 70 novel transcripts. Many of the novel transcripts are lncRNAs. We used an indepenedent dataset to interrogate our novel transcripts and found that the novel lncRNA BANCR is a BRAF-regulated lncRNA recurrently upregulated in melanoma. Knockdown of BANCR impairs melanoma cell migration. Whole transcriptome RNA-seq followed assembly to Refseq/Gencode and de novo transcript assembly. RNA-seq performed on: 2 BRAFv600e melanomas, melanocytes+RFP control and melanocytes + BRAFv600e. We discovered protein-coding transcripts, annotated ncRNAs and novel transcripts (including lncRNAs) regulated by BRAFv600e also coordinately expressed in melanoma.
2012-04-28 | E-GEOD-33092 | biostudies-arrayexpress
Project description:Mutational activation of the BRAF proto-oncogene in melanocytes reliably produces benign nevi (pigmented “moles”), yet the same change is the most common driver mutation in melanoma. One of the abiding mysteries of carcinogenesis is why oncogene activation doesn’t always lead to cancer. The reason nevi stop growing, and do not progress to melanoma, is widely attributed to a cell-autonomous process of “oncogene-induced senescence”. Senescence is usually accompanied by distinctive gene expression and various gene expression “signatures” have been developed to help investigators identify senescent cells and distinguish them from cells that have become growth arrested by other processes. Using a mouse model of Braf-driven nevus formation, we analyzed single-cell gene expression and found no evidence that nevus cells are senescent, either compared with other skin cells, or other melanocytes.
2020-10-20 | GSE154679 | GEO
Project description:Melanocytes within benign human nevi are the paradigm for tumor suppressive senescent cells in a pre-malignant neoplasm. These cells typically contain mutations in either the BRAF or N-RAS oncogene and express markers of senescence, including p16. However, a nevus can contain 10s to 100s of thousands of clonal melanocytes and approximately 20-30% of melanoma are thought to arise in association with a pre-existing nevus. Neither observation is indicative of fail-safe senescence-associated proliferation arrest and tumor suppression. We set out to better understand the status of nevus melanocytes. Proliferation-promoting Wnt target genes, such as cyclin D1 and c-myc, were repressed in oncogene-induced senescent melanocytes in vitro, and repression of Wnt signaling in these cells induced a senescent-like state. In contrast, cyclin D1 and c-myc were expressed in many melanocytes of human benign nevi. Specifically, activated Wnt signalling in nevi correlated inversely with nevus maturation, an established dermatopathological correlate of clinical benignancy. Single cell analyses of lone epidermal melanocytes and nevus melanocytes showed that expression of proliferation-promoting Wnt targets correlates with prior proliferative expansion of p16-expressing nevus melanocytes. In a mouse model, activation of Wnt signaling delayed, but did not bypass, senescence of oncogene-expressing melanocytes, leading to massive accumulation of proliferation-arrested, p16-positive non-malignant melanocytes. We conclude that clonal hyperproliferation of oncogene-expressing melanocytes to form a nevus is facilitated by transient delay of senescence due to activated Wnt signaling. The observation that activation of Wnt signaling correlates inversely with nevus maturation, an indicator of clinical benignancy, supports the notion that persistent destabilization of senescence by Wnt signaling contributes to the malignant potential of nevi. We used microarrays to detail the global programme of gene expression after lentiviral infection of BRAF in 3 replicates. Primary human melanocytes were infected/uninfected with lentivirus containing either an Empty Vector or activated BRAFV600E mutant in three biological replicates
2013-08-01 | E-GEOD-46801 | biostudies-arrayexpress
Project description:Approximately 50% of melanomas harbor an activating BRAFV600E mutation. Standard of care involves a combination of inhibitors targeting mutant BRAF and MEK1/2, the substrate for BRAF in the MAPK pathway. PTEN loss of function mutations occur in 40% of BRAFV600E melanomas, resulting in increased PI3K/AKT activity that enhances resistance to BRAF/MEK combination inhibitor therapy. To compare the response of PTEN null to PTEN wild type cells in an isogenic background, CRISPR was used to knock out PTEN in the A375 melanoma cell line that harbors a BRAFV600E mutation. RNA sequencing and functional kinome analysis revealed the loss of PTEN led to an induction of FOXD3 and an increase in expression of the FOXD3 target gene, ERBB3/HER3. Inhibition of BRAFand MEK1/2 in PTEN null, BRAFV600E cells dramatically induced expression of ERBB3/HER3 relative to wild type cells. A synergy screen of epigenetic modifiers and kinase inhibitors in combination with inhibitors for mutant BRAF/MEK1/2 identified the pan ERBB/HER inhibitor, neratinib, as reversing the resistance observed in PTEN null, BRAFV600E cells. The findings indicate PTEN null BRAFV600E melanoma becomes dependent on ERBB/HER signaling when treated with clinically approved BRAF and MEK inhibitors. Future studies are warranted to test neratinib reversal of resistance in patient melanomas expressing ERBB3/HER3 in combination with its dimerization partner ERBB2/HER2.
2024-04-23 | PXD033866 | Pride
Project description:Thousands of enhancers are characterized in the human genome, yet few have been shown important in cancer. Inhibiting oncokinases, such as EGFR, ALK, HER2, and BRAF, is a mainstay of current cancer therapy but is hindered by innate drug resistance mediated by upregulation of the HGF receptor, MET. The mechanisms mediating such genomic responses to targeted therapy are unknown. Here, we identify lineage-specific MET enhancers for multiple common tumor types, including a melanoma lineage-specific MET enhancer that displays inducible chromatin looping and MET gene induction upon BRAF inhibition. Epigenomic analysis demonstrated that the melanocyte-specific transcription factor, MITF, mediates this enhancer function. Targeted genomic deletion (<7bp) of the MITF motif within the MET enhancer suppressed inducible chromatin looping and innate drug resistance, while maintaining MITF-dependent, inhibitor-induced melanoma cell differentiation. Epigenomic analysis can thus guide functional disruption of regulatory DNA to decouple pro- and anti-oncogenic functions of tumor lineage-enriched transcription factors mediating innate resistance to oncokinase therapy. MITF ChIP-seq was performed in primary human melanocytes with overexpression of BRAFV600E or a lentiviral control (RFP), and in COLO829 melanoma cells treated with DMSO, or PLX4032
2014-01-14 | E-GEOD-50681 | biostudies-arrayexpress
Project description:Approximately 50% of melanomas harbor an activating BRAFV600E mutation. Standard of care involves a combination of inhibitors targeting mutant BRAF and MEK1/2, the substrate for BRAF in the MAPK pathway. PTEN loss of function mutations occur in 40% of BRAFV600E melanomas, resulting in increased PI3K/AKT activity that enhances resistance to BRAF/MEK combination inhibitor therapy. To compare the response of PTEN null to PTEN wild type cells in an isogenic background, CRISPR was used to knock out PTEN a melanoma cell line that harbors a BRAFV600E mutation. RNA sequencing and functional kinome analysis revealed the loss of PTEN led to an induction of FOXD3 and an increase in expression of the FOXD3 target gene, ERBB3/HER3. Inhibition of BRAF and MEK1/2 in PTEN null, BRAFV600Ecells dramatically induced expression of ERBB3/HER3 relative to wild type cells. A synergy screen of epigenetic modifiers and kinase inhibitors in combination with BRAFi/MEKi identified the pan ERBB/HER inhibitor, neratinib, as reversing the resistance observed in PTEN null, BRAFV600Ecells. The findings indicate that PTEN null BRAFV600E melanoma exhibits increased reliance on ERBB/HER signaling when treated with clinically approved BRAFi/MEKi combinations. Future studies are warranted to test neratinib reversal of resistance in patient melanomas expressing ERBB3/HER3 in combination with its dimerization partner ERBB2/HER2.
2024-04-23 | GSE255541 | GEO
Project description:Malignant melanoma is characterized by frequent metastasis, however specific changes that regulate this process have not been clearly delineated. Although it is well known that Wnt signaling is frequently dysregulated in melanoma, the functional implications of this observation are unclear. By modulating beta-catenin levels in a mouse model of melanoma that is based on melanocyte-specific Pten loss and BrafV600E mutation, we demonstrate that beta-catenin is a central mediator of melanoma metastasis to lymph node and lung. In addition to altering metastasis, beta-catenin levels control tumor differentiation and regulate both MAPK/Erk and PI3K/Akt signaling. Highly metastatic tumors with beta-catenin stabilization are very similar to a subset of human melanomas; together these findings establish Wnt signaling as a metastasis regulator in melanoma. MoGene-1_0-st-v1: Four samples total. Two biological replicates of uncultured Pten/Braf murine melanomas and two biological replicates of uncultured Pten/Braf/Bcat-STA murine melanomas. MoEx-1_0-st-v1: Two samples total. Dissociated tumor and FACS-enriched Pten/Braf and Pten/Braf/Bcat-STA murine melanoma.
2011-10-12 | E-GEOD-32907 | biostudies-arrayexpress
Project description:The oncogenic mutation BRAFV600E is a common event in nevi and melanomas, which are aggressive skin tumors characterized by MAPK signaling pathway activation. It has been observed that mutated benign melanocytic lesions can remain unchanged for decades, but also proliferate or undergo oncogene-induced senescence. The purpose of this study was to investigate the presence of a gene expression signature in BRAFV600E mutated nevi compared to wild-type ones, all derived from sun exposed sites. Microdissected tissues from excisional biopsies of acquired nevi were analyzed to detect the presence of BRAF and NRAS mutations and to profile whole genome expression by means of oligonucleotide microarrays. BRAFV600E mutation was evidenced in 64% of nevi, while no NRAS mutations were detected. Functional analysis of genes differentially expressed between wild-type and mutated lesions pointed out the role of oxidative stress in causing the oncogenic BRAF mutation and that the direct consequence of constitutive activation of BRAF-MEK-ERK pathway, in a benign contest, is the activation of apoptosis, autophagy and senescence. Our data also indicate that in mutated lesions, p53 plays a crucial role in the maintenance of the benign status.
2024-12-31 | GSE23976 | GEO
Project description:The oncogenic mutation BRAFV600E is a common event in nevi and melanomas, which are aggressive skin tumors characterized by MAPK signaling pathway activation. It has been observed that mutated benign melanocytic lesions can remain unchanged for decades, but also proliferate or undergo oncogene-induced senescence. The purpose of this study was to investigate the presence of a gene expression signature in BRAFV600E mutated nevi compared to wild-type ones, all derived from sun exposed sites. Microdissected tissues from excisional biopsies of acquired nevi were analyzed to detect the presence of BRAF and NRAS mutations and to profile whole genome expression by means of oligonucleotide microarrays. BRAFV600E mutation was evidenced in 64% of nevi, while no NRAS mutations were detected. Functional analysis of genes differentially expressed between wild-type and mutated lesions pointed out the role of oxidative stress in causing the oncogenic BRAF mutation and that the direct consequence of constitutive activation of BRAF-MEK-ERK pathway, in a benign contest, is the activation of apoptosis, autophagy and senescence. Our data also indicate that in mutated lesions, p53 plays a crucial role in the maintenance of the benign status. In our study, in order to understand the role of BRAF mutation in acquired nevi, we performed gene expression profiling analysis on fourteen lesions derived from intermittently exposed sites, using whole genome oligonucleotide microarrays. Expression data were coupled with sequencing results on BRAF and NRAS genes and class comparison algorithms were applied to detect sequences differentially expressed between BRAFV600E and BRAFwt-NRASwt lesions. Some of the obtained results were further validated by Real-Time RT-PCR on an independent cohort of samples. Mutation analysis evidenced BRAF mutations in 64% of the common acquired nevi. All the mutations consisted in the substitution V600E (T1799A). No alteration was found on exon 11 of the BRAF gene nor on exons 1 and 2 of the NRAS gene, as expected since no lesion came from chronically exposed sites. Transcriptome analysis was carried out using oligo-microarrays and differential expression was tested applying the Linear Models package LIMMA available at www.bioconductor.org that uses Bayesian statistics to compute the probability of a gene being differentially expressed. Only 25 transcripts had B value greater then 2. We then performed a one-way ANOVA, dividing samples into three classes according to their BRAF mutational status (wt, ++, +++) as assessed by pyrosequencing. We found 2882 known transcripts by selecting those with ANOVA p-value<0.01 and increasing or decreasing expression trends along the three classes. Functional analysis was performed using the MetaCoreTM software package to identify overrepresented functional processes. BRAF signature, acquired nevi, gene expression profiling "++ and +++" refer to the percentage of alleles carrying the mutation in the *BRAF*V600E lesions. This has been assessed by pyrosequencing analysis (Venesio et al, 2008. PMID= 18408659).
2016-06-30 | E-GEOD-23976 | biostudies-arrayexpress