Myocilin, a causative gene for open-angle glaucoma, encodes a secreted glycoprotein of unknown function. To elucidate its function(s), we produced a stably transfected HEK293 cell line expressing myocilin and compared the expression profiles between the myocilin-expressing cell line and a vector control cell line using Affymetrix GeneChip U133 plus 2.0 array. A significant portion of differentially-expressed genes in the myocilin-expressing cells was associated with cell growth and cell death, suggesting that myocilin may have an important role regulating cell growth/survival..
Myocilin regulates cell proliferation and survival.
Cell line
View SamplesOur data suggest that CNTF remodels the transcription profile of Mller (glial) cells leading to induction of networks associated with transcription, cell cycle regulation and inflammatory response. CNTF also appears to function as an inducer of gliosis in the retina. These studies provide new insights into the biological functions of cytokines in the retina.
Ciliary neurotrophic factor induces genes associated with inflammation and gliosis in the retina: a gene profiling study of flow-sorted, Müller cells.
Specimen part, Treatment, Time
View SamplesWe examined gene expression of LAPC4 cells after knocking down -TrCP, androgen ablation, or the combined treatments compared to non treated cells.
beta-TrCP inhibition reduces prostate cancer cell growth via upregulation of the aryl hydrocarbon receptor.
Cell line
View SamplesTo better understand the mechanistic basis of aging and its relationship with retinal degeneration, we examined gene expression changes in aging rod photoreceptors. Rod photoreceptor cell death is a feature of normal retinal aging and is accelerated in many retinal degenerative diseases, including AMD, the leading cause of untreatable adult blindness in the United States and other western countries. To our knowledge, the examination of age-related gene expression changes in a specific neuronal cell-type is novel, and it has allowed us to identify significant age-related changes with better resolution than is possible with whole retina samples. We used flow cytometry and a transgenic mouse with GFP-tagged rod photoreceptors to purify this specific cell population, and gene expression changes were evaluated at three time points using microarrays and quantitative RT-PCR. Our results suggest that aging is progressive, beginning even in young adult mice. Although rod photoreceptors are highly specialized neurons, our analyses revealed changes in consensus pathways of aging, including oxidative phosphorylation and stress responses affecting transcription and inflammation. In addition, we identified stress response processes that may be especially relevant for the aging retina and retinal diseases, such as angiogenesis and nuclear receptor signaling pathways that affect retinoid and lipid metabolism.
Distinct signature of altered homeostasis in aging rod photoreceptors: implications for retinal diseases.
Age, Specimen part
View SamplesIn this study, we set out to identify those molecular features of the POU transcription factor Oct4 that are responsible for inducing pluripotency in somatic cells. Oct4 is known to have a strong preference to cooperate with Sox2 on heterodimeric SoxOct elements predominantly found in enhancers of genes expressed in embryonic stem cells (ESCs). To test whether this partnership is specific to Oct4, we compared its DNA recognition and reprogramming activities to the paralogous transcription factor Oct6, which cannot induce and maintain pluripotency in mouse cells. By analyzing ChIP-Seq data and performing quantitative dimerization assays, we found that in somatic cells, instead of heterodimerzing with Sox-factors, Oct6 more potently homodimerizes on OctOct elements. We identified that a single amino acid is crucial in directing binding to the respective composite DNA element. As a consequence, just changing this one amino acid hampers Oct4 in generating induced pluripotent stem cells (iPSCs). In contrast, the reverse mutation in Oct6 did not augment its reprogramming activity. This was achieved with at least two additional exchanges. In summary, we demonstrate that cell-type specific POU factor function is determined by a limited set of residues that affect DNA and partner factor interactions. Such relatively minor changes lead to a pronounced impact on regulatory function and reprogramming activity.
Changing POU dimerization preferences converts Oct6 into a pluripotency inducer.
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View SamplesA large body of evidence has demonstrated that many human tumors are maintained by a small cell population called cancer stem cells (CSCs) or tumor progenitors, which are responsible for tumor formation, therapy resistance and metastasis. We found that ionizing radiation treatment enriches for the CSC phenotype and properties by preferential survival and expansion of tumor progenitor cells. Our studies revealed that aldehyde dehydrogenase (ALDH) activity is indicative of prostate tumor progenitor cells with increased chemo- and radioresistance, enhanced migratory potential, improved DNA- double strand break repair and activation of the signaling pathways, which promote self-renewal and epithelial-mesenchymal transition. We found that X-ray irradiation can convert the bulk tumor cells to more clonogenic and radioresistant population positive for expression of CSC markers. For the first time we showed that irradiation increases histone H3K4 and H3K36 methylation in prostate cancer cells, thereby reactivating transcription of epigenetically silenced target genes. We showed that radioresistant tumor progenitor population undergoes a phenotypical switching during the course of irradiation, suggesting that controlling the phenotypical and functional properties of CSCs during radiation therapy is ultimative for the optimization of treatment strategies. Our studies have shown that CSC markers may be beneficial in prediction of tumor radiocurability, and combination of irradiation with therapies directed against CSCs can be a useful strategy to improve cancer treatment.
Aldehyde Dehydrogenase Is Regulated by β-Catenin/TCF and Promotes Radioresistance in Prostate Cancer Progenitor Cells.
Specimen part
View Samples