The LIM-only protein FHL2 acts as a transcriptional modulator that positively or negatively regulates multiple signaling pathways. We recently reported that FHL2 cooperates with CBP/p300 in the activation of -catenin/TCF target gene cyclin D1. In this paper, we demonstrate that FHL2 is associated with the cyclin D1 promoter at the TCF/CRE site, providing evidence that cyclin D1 is a direct target of FHL2. We show that deficiency of FHL2 greatly reduces the proliferative capacity of spontaneously immortalized mouse fibroblasts which is associated with decreased expression of cyclin D1 and p16INK4a, and hypophosphorylation of Rb. Reexpression of FHL2 in FHL2-null fibroblasts efficiently restores cyclin D1 levels and cell proliferative capacity, indicating that FHL2 is critical for cyclin D1 activation and cell growth. Moreover, ectopic cyclin D1 expression is sufficient to override growth inhibition of immortalized FHL2-null fibroblasts. Gene expression profiling revealed that FHL2 deficiency triggers a broad change of the cell cycle program that is associated with downregulation of several G1/S and G2/M cyclins, E2F transcription factors and DNA replication machinery, thus correlating with reduced cell proliferation. This change also involves downregulation of the negative cell cycle regulators, particularly INK4 inhibitors, which could counteract the decreased expression of cyclins, allowing cells to grow. Our study illustrates that FHL2 can act on different aspects of the cell cycle program to finely regulate cell proliferation.
The LIM-only protein FHL2 regulates cyclin D1 expression and cell proliferation.
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View SamplesEndothelial inflammation contributes to the pathogenesis of numerous human diseases; however, the role of tumor endothelial inflammation in the growth of experimental tumors and its influence on the prognosis of human cancers is less understood. TNF-, an important mediator of tumor stromal inflammation, is known to target the tumor vasculature. In this study, we demonstrate that B16-F1 melanomas grew more rapidly in C57BL/6 wild-type (WT) mice than in syngeneic mice with germline deletions of both TNF- receptors (KO). This enhanced tumor growth was associated with increased COX2 inflammatory expression in WT tumor endothelium compared to endothelium in KO mice. We purified endothelial cells from WT and KO tumors and characterized dysregulated gene expression, which ultimately formed the basis of a 6-gene Inflammation-Related Endothelial-derived Gene (IREG) signature. This inflammatory signature expressed in WT tumor endothelial cells was trained in human cancer datasets and predicted a poor clinical outcome in breast cancer, colon cancer, lung cancer and glioma. Consistent with this observation, conditioned media from human endothelial cells treated with pro-inflammatory cytokines (TNF- and interferons) accelerated the growth of human colon and breast tumors in immune-deprived mice as compared with conditioned media from untreated endothelial cells. These findings demonstrate that activation of endothelial inflammatory pathways contributes to tumor growth and progression in diverse human cancers.
Tumor endothelial inflammation predicts clinical outcome in diverse human cancers.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Direct recruitment of polycomb repressive complex 1 to chromatin by core binding transcription factors.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Integrating factor analysis and a transgenic mouse model to reveal a peripheral blood predictor of breast tumors.
Specimen part
View SamplesFemale MMTV/c-MYC transgenic mice expressed the c-MYC proto-oncogene or a more stable point mutation variant (T58A) of the gene under the control of the hormone-responsive MMTV long terminal repeat (LTR) in an FVB/NJ background (Jackson Laboratories, Bar Harbor, ME). The hormones released during pregnancy and lactation have been shown to enhance expression of the oncogene. Thus, the mice were maintained in a continuous breeding program. Mice were monitored twice weekly for tumor development by palpation and tumors were measured twice weekly. Once the tumors reached 3cm3 the animals were sacrificed and tissue was obtained to confirm the tumors by histological analysis. As a control, female mice of the same age and background strain were maintained in the same facility and under the same breeding conditions as their transgenic counterparts.
Integrating factor analysis and a transgenic mouse model to reveal a peripheral blood predictor of breast tumors.
Specimen part
View SamplesThe efficacy and exceptionally good tolerance of estrogen blockade in the treatment of breast cancer is well recognized but novel agents are required, especially to take advantage of the multiple consecutive responses obtained in breast cancer progressing following previous hormone therapy, thus delaying the use of cytotoxic chemotherapy with its usually serious side effects. Acolbifene (ACOL) is a novel and unique antiestrogen completely free of estrogen-like activity in both the mammary gland and uterus while preventing bone loss. From the preclinical and clinical data so-far available, this new antiestrogen represents a unique opportunity for a highly potent and specific blockade of estrogen action in the mammary gland and uterus while exerting estrogen-like beneficial effects in other tissues (selective estrogen receptor modulator or SERM activity). In order to better understand the specificity of action of acolbifene, we have used Affymetrix GeneChips containing 45,000 probe sets to analyze 34,000 genes to determine the specificity of this compound compared to the pure antiestrogen fulvestrant, as well as the mixed antagonists/agonists tamoxifen and raloxifene to block the effect of estradiol (E2) and to induce effects of their own on gene expression in the mouse mammary gland. The genes modulated by E2 were those identified in two separate experiments and validated by quantitative real-time PCR (Q_RT-PCR). Three hours after the single subcutaneous injection of E2 (0.05 ug), the simultaneous administration of acolbifene, fulvestrant, tamoxifen and raloxifene blocked by 98%, 62%, 43% and 92% the number of E2-upregulated genes, respectively. On the other hand, 70%, 10%, 25% and 55% of the genes down-regulated by E2 were blocked by the same compounds. Acolbifene was also the compound which, when used alone, modulated the smallest number of genes also influenced by E2, namely 4%, thus possibly explaining the potent tumoricidal action of this compound in human breast cancer xenografts where 61% of tumors disappeared, thus bringing a new paradigm in the hormonal therapy of breast cancer.
Specific transcriptional response of four blockers of estrogen receptors on estradiol-modulated genes in the mouse mammary gland.
Specimen part, Treatment
View SamplesArx is a paired-box homeodomain transcription factor and the vertebrate ortholog to the Drosophila aristaless (al) gene. Mutations in Arx are associated with a variety of human diseases, including X-linked infantile spasm syndrome (OMIM: 308350), X-linked myoclonic epilepsy with mental retardation and spasticity (OMIM: 300432), X-linked lissencephaly with ambiguous genitalia (OMIM: 300215), X-linked mental retardation 54 (OMIM: 300419), and agenesis of the corpus callosum with abnormal genitalia (OMIM: 300004). Arx-deficient mice exhibit a complex, pleiotrophic phenotype, including decreased proliferation of neuroepithelial cells of the cortex, dysgenesis of the thalamus and olfactory bulbs, and abnormal nonradial migration of GABAergic interneurons. It has been suggested that deficits in interneuron specification, migration, or function lead to loss of inhibitory neurotransmission, which then fails to control excitatory activity and leads to epilepsy or spasticities. Given that Arx mutations are associated with developmental disorders in which epilepsy and spasticity predominate and that Arx-deficient mice exhibit deficits in interneuron migration, understanding the function of Arx in interneuron migration will prove crucial to understanding the pathology underlying interneuronopathies. Yet, downstream transcriptional targets of Arx, to date, remain unidentified.
Identification of Arx transcriptional targets in the developing basal forebrain.
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View SamplesDynamic regulation of histone methylation by methyltransferases and demethylases plays a central role in regulating the fate of embryonic stem (ES) cells. The histone H3K9 methyltransferase KMT1E, formerly known as ESET or Setdb1, is essential to embryonic development as the ablation of the Setdb1 gene results in peri-implantation lethality and prevents the propagation of ES cells. However, Setdb1- null blastocysts do not display global changes in H3K9 methylation or DNA methylation, arguing against a genome- wide defect. Here we show that conditional deletion of the Setdb1 gene in ES cells results in the upregulation of lineage differentiation markers, especially trophectoderm-specific factors, similar to effects observed upon loss of Oct3/4 expression in ES cells. We demonstrate that KMT1E deficiency in ES cells leads to a decrease in histone H3K9 methylation at and derepression of trophoblast-associated genes such as Cdx2. Furthermore, we find genes that are derepressed upon Setdb1 deletion to overlap with known targets of polycomb mediated repression, suggesting that KMT1E mediated H3K9 methylation acts in concert with polycomb controlled H3K27 methylation. Our studies thus demonstrate an essential role for KMT1E in the control of developmentally regulated gene expression programs in ES cells.
KMT1E mediated H3K9 methylation is required for the maintenance of embryonic stem cells by repressing trophectoderm differentiation.
Specimen part, Treatment
View SamplesWe used microarrays to detail the global gene expression and identified differentially expressed gene list between wild-type anterior prostates and Ptenpc-/- anterior prostates, Ptenpc-/-Smad4pc-/- and Ptenpc-/- anterior prostates, Ptenpc-/-p53pc-/- and Ptenpc-/- anterior prostates at 15 weeks of age.
SMAD4-dependent barrier constrains prostate cancer growth and metastatic progression.
Age, Specimen part
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