This SuperSeries is composed of the SubSeries listed below.
Wnt signaling potentiates nevogenesis.
Specimen part, Cell line
View SamplesMelanocytes 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.
Wnt signaling potentiates nevogenesis.
Specimen part
View SamplesSince the discovery of induced pluripotent stem cells there has been intense interest in understanding the mechanisms that allow a somatic cell to be reprogrammed back to a pluripotent state. Several groups have studied the alterations in gene expression that occur as somatic cells modify their genome to that of an embryonic stem cell. Underpinning many of the gene expression changes are modifications to the epigenetic profile of the associated chromatin. We have used a large-scale shRNA screen to identify epigenetic modifiers that act as barriers to reprogramming. We have uncovered an important role for TRIM28 in cells resisting transition between somatic and pluripotent states. TRIM28 achieves this by maintaining the H3K9me3 repressed state and keeping endogenous retroviruses silenced. We propose that knockdown of TRIM28 during reprogramming results in more plastic H3K9me3 domains, dysregulation of genes nearby H3K9me3 marks, and up regulation of endogenous retroviruses, thus facilitating the transition through reprogramming. Overall design: Gene expression profiling using high through put sequencing at day 7 of Oct4, Sox2, Klf4 and cMyc (OSKM) expression in mouse embryonic fibroblasts with or without Trim28 / Setdb1 knockdown
TRIM28 is an Epigenetic Barrier to Induced Pluripotent Stem Cell Reprogramming.
Specimen part, Cell line, Treatment, Subject
View SamplesMutations in both RAS and the PTEN/PIK3CA/AKT signaling module are found in the same human tumors. PIK3CA and AKT are downstream effectors of RAS, and the selective advantage conferred by mutation of two genes in the same pathway is unclear. Based on a comparative molecular analysis, we show that activated PIK3CA/AKT is a weaker inducer of senescence than is activated RAS. More-over, concurrent activation of RAS and PIK3CA/AKT impairs RAS-induced senescence.
Activation of the PIK3CA/AKT pathway suppresses senescence induced by an activated RAS oncogene to promote tumorigenesis.
Cell line
View SamplesOIS is characterized by a stable proliferation arrest and secretion of pro-inflammatory cytokines and chemokines, the senescence-associated secretory phenotype (SASP). Proliferation arrest and the SASP collaborate to enact tumor suppression, the former by blocking cell proliferation and the latter by recruiting immune cells to clear damaged cells. However, the interactions of OIS cells with the immune system are still poorly defined. Here we show that engagement of OIS in primary human melanocytes, specifically by melanoma driver mutations NRASQ61K and BRAFV600E, causes expression of the MHC class II antigen presentation apparatus, via secreted IL1ß signaling and expression of CIITA, a master regulator of MHC class II gene transcription. Overall design: We quantify transcription via high throughput RNA sequencing in nevus melanocytes in cross FVB/NJ mice with Cre inducible NRAS61K with an MHCII cross
Oncogene-Expressing Senescent Melanocytes Up-Regulate MHC Class II, a Candidate Melanoma Suppressor Function.
Cell line, Subject
View SamplesActivation of the hypoxia inducible transcription factor HIF-alpha and the NF-kappaB pathway promotes inflammation mediated tumor progression.
The hypoxia-inducible transcription factor ZNF395 is controlled by IĸB kinase-signaling and activates genes involved in the innate immune response and cancer.
Cell line, Treatment
View SamplesWe have performed whole genome expression arrays covering over 47000 transcripts comparing the transcriptional profile of NKp80+ to NKp80- CD8+ CCR7- alpha beta T cells. A highly similar global gene expression profile was observed between both memory phenotype T cell subsets. Interestingly, the majority of differentially expressed genes are immune-associated. NKp80+ cells contained markedly increased levels of transcripts encoding for MHC class I and II molecules and for numerous members of the KIR family. Also other NK-related transcripts were more abundantly expressed in the NKp80+ subset. With regards to cytokines, chemokines and their receptors, transcripts important for homeostasis and proliferation are expressed differently. Also transcripts encoding for adhesion molecules are present at different levels in both T cell subsets. Further cytotoxic effector molecules are expressed differently.
NKp80 defines and stimulates a reactive subset of CD8 T cells.
Sex, Specimen part
View SamplesSWP73 subunits of SWI/SNF chromatin remodeling complexes (CRCs) are involved in key developmental pathways in Arabidopsis. We found, using microarray that inactivation of SWP73B caused altered expression of genes belonging to various regulatory pathways, including leaf and flower development. On the basis of this experiment and our other data we concluded that SWP73B modulates major developmental pathways.
SWP73 Subunits of Arabidopsis SWI/SNF Chromatin Remodeling Complexes Play Distinct Roles in Leaf and Flower Development.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A multiple myeloma classification system that associates normal B-cell subset phenotypes with prognosis.
Specimen part, Disease
View SamplesTodays diagnostic tests for multiple myeloma (MM) reflect the criteria of the updated WHO classification based on biomarkers and clinicopathologic heterogeneity. To that end, we propose a new subtyping of myeloma plasma cells (PC) by B-cell subset associated gene signatures (BAGS), from the normal B-cell hierarchy in the bone marrow (BM). To do this, we combined FACS and GEP data from normal BM samples to generate classifiers by BAGS for the PreBI, PreBII, immature (Im), nave (N), memory (M) and PC subsets. The resultant tumor assignments in available clinical datasets exhibited similar BAGS subtype frequencies in four cohorts across 1302 individual cases. The prognostic impact of BAGS was analyzed in patients treated with high dose melphalan as first line therapy in three prospective trials: UAMS, HOVON65/GMMG-HD4 and MRC Myeloma IX with Affymetrix U133 plus 2.0 microarray data available from diagnostic myeloma PC samples. The BAGS subtypes were significantly associated with progression free (PFS) and overall survival (OS) (PFS, P=3.05e06 and OS, P=1.06e11) in a meta-analysis of 926 pts. The major impact was observed within the PreBII and M subtypes conferred with significant inferior prognosis compared to the Im, N and PC subtypes. Cox proportional hazard meta-analysis documented that the BAGS subtypes added significant and independent prognostic information to the TC classification system and ISS staging. BAGS subtype analysis identified transcriptome differences and a number of novel differentially spliced genes. We have identified hierarchal subtype differences in the myeloma plasma cells, with prognostic impact. This observation support an acquired reversible B-cell trait and phenotypic plasticity as a hallmark, also in MM.
A multiple myeloma classification system that associates normal B-cell subset phenotypes with prognosis.
Specimen part
View Samples