Project description:Pituitary adenomas cause significant endocrine and mass-related morbidity. Not much is known about mechanisms underlying pituitary tumor pathogenesis.We searched for a side population (SP) in pituitary tumor, representing cells with high efflux capacity and potentially enriching for cancer/tumor stem cells (CSC/TSC). Human pituitary adenomas contain a SP irrespective of hormonal phenotype. This adenoma SP, as well as the further purified SP (pSP) depleted from endothelial and immune cells, enriches for cells that express ‘tumor stemness’ markers and signaling pathways, including epithelial-mesenchymal transition (EMT)-linked factors. The adenomas were found to contain self-renewing sphere-forming cells, considered a property of TSC. The sphere-initiating cells were retrieved in the pSP.Because benign pituitary adenomas do not grow in vitro and failed to expand in immunodeficient mice, the pituitary tumor cell line AtT20 was further used. We identified a SP in this cell line and found it more tumorigenic than the main population (MP). Of the two EMT-regulatory pathways tested, inhibition of Cxcr4 signaling reduced EMT-linked cell motility in vitro as well as xenograft tumor growth, whereas activation of TGFβ had no effect.The tumor pSP showed upregulated expression of the pituitary stem cell marker SOX2. Pituitaries from dopamine receptor D2 knockout (Drd2-/-) mice bearing prolactinomas, contain more pSP, Sox2+ and colony-forming cells than wildtype glands.In conclusion, we detected a SP in pituitary tumors and identified TSC-associated characteristics. Our study may contribute to a better understanding of pituitary tumor pathogenesis and lead to new therapeutic targets. We determined gene expression profiles for 9 human pituitary adenoma samples (5 x NF-A; 4 x GH-A). The samples were obtained immediately after transsphenoidal resection (by the neurosurgeon Dr. van Loon, Division Neurosurgery, University Hospitals Leuven). Informed consent was received from the patients. Hormonal phenotype was determined by the Department of Imaging and Pathology (University Hospitals Leuven). For each sample, total SP and MP cells were sorted by FACS. Separate assays were run subsequently for the two fractions. As such we present data from 18 microarrays.

Project description:Pituitary adenomas cause significant endocrine and mass-related morbidity. Not much is known about mechanisms underlying pituitary tumor pathogenesis. We searched for a side population (SP) in pituitary tumor, representing cells with high efflux capacity and potentially enriching for cancer/tumor stem cells (CSC/TSC). Human pituitary adenomas contain a SP irrespective of hormonal phenotype. This adenoma SP, as well as the further purified SP (pSP) depleted from endothelial and immune cells, enriches for cells that express ‘tumor stemness’ markers and signaling pathways, including epithelial-mesenchymal transition (EMT)-linked factors. The adenomas were found to contain self-renewing sphere-forming cells, considered a property of TSC. The sphere-initiating cells were retrieved in the pSP. Because benign pituitary adenomas do not grow in vitro and failed to expand in immunodeficient mice, the pituitary tumor cell line AtT20 was further used. We identified a SP in this cell line and found it more tumorigenic than the main population (MP). Of the two EMT-regulatory pathways tested, inhibition of Cxcr4 signaling reduced EMT-linked cell motility in vitro as well as xenograft tumor growth, whereas activation of TGFβ had no effect. The tumor pSP showed upregulated expression of the pituitary stem cell marker SOX2. Pituitaries from dopamine receptor D2 knockout (Drd2-/-) mice bearing prolactinomas, contain more pSP, Sox2+ and colony-forming cells than wildtype glands. In conclusion, we detected a SP in pituitary tumors and identified TSC-associated characteristics. Our study may contribute to a better understanding of pituitary tumor pathogenesis and lead to new therapeutic targets. We determined gene expression profiles for 5 human pituitary adenoma samples (all NF-A type). The samples were obtained immediately after transsphenoidal resection (by the neurosurgeon Dr. van Loon, Division Neurosurgery, University Hospitals Leuven). Informed consent was received from the patients. Hormonal phenotype was determined by the Department of Imaging and Pathology (University Hospitals Leuven). For each sample, CD31¯/CD45¯ SP (purified SP or pSP) and pMP cells were sorted by FACS. Separate assays were run subsequently for the two fractions. As such we present data from 10 microarrays.

Project description:The recent identification of cancer stem cells (CSCs) in multiple human cancers provides a new inroad to understanding tumorigenesis at the cellular level. CSCs are defined by their characteristics of self-renewal, multipotentiality, and tumor initiation upon transplantation. By testing for these defining characteristics, we provide evidence for the existence of CSCs in a transgenic mouse model of glioma, S100Ã-verbB;Trp53. In this glioma model, CSCs are enriched in the side-population (SP) cells. These SP cells have enhanced tumor-initiating capacity, self-renewal, and multipotentiality compared to non-SP cells from the same tumors. Furthermore, gene expression analysis comparing FACS-sorted cancer SP cells to non-SP cancer cells and normal neural SP cells identified 45 candidate genes that are differentially expressed in glioma stem cells. We validated the expression of two genes from this list (S100a4 and S100a6) in primary mouse gliomas and human glioma samples. Analyses of xenografted human GBM (glioblatoma multiforme) cell lines and primary human glioma tissues show that S100A4 and S100A6 are expressed in a small subset of cancer cells and that their abundance is positively correlated to tumor grade. In conclusion, this study shows that CSCs exist in a mouse glioma model, suggesting that this model can be used to study the molecular and cellular characteristics of CSCs in vivo and to further test the cancer stem cell hypothesis. Experiment Overall Design: This study features two factors, injected cell origin (either tumorsphere or neurosphere) and FACS cell population (either side population or non-side population cells). There were two different tumorspheres, labeled 3447 and 4346 that were isolated from brain tumors in S100beta-verbB;p53-/- or S100beta-verbB;p53+/- mice. The tumorspheres were injected separately into the brains of NOD.Cg-Prkdc<scid>Il2rg<tm1Wjl>/SzJ mice to generate biological triplicates of each primary tumor. Tumorspheres were isolated and cultured before FACS sorting to obtain side population and non-side population cells. As a control, untransformed neurospheres from three independent S100beta-verbB;p53-/- or S100beta-verbB;p53+/- mice were isolated, cultured, and FACS sorted to obtain side population and non-side population cells. Side population and non-side population cells cultured from three mice injected with the 3447 cultured tumorspheres were assayed for gene expression (six samples). Side-population stem cells cultured from three mice injected with the 4346 cultured tumorspheres were assayed for gene expression (three samples). Side-population and non-side population cells cultured from three mice injected with the neurospheres were assayed for gene expression (six samples).

Project description:The side population (SP), recently identified in several normal tissues and in a variety of tumors, may comprise cells endowed with stem cell features. In this study, we investigated the presence of SP in epithelial ovarian cancer (EOC) and found it in 4 out of 6 primary cultures from xenotransplants, as well as in 9 out of 25 clinical samples analyzed. SP cells from one xenograft bearing a large SP fraction were characterized in detail and they were capable of recreate the full repertoire of cancer cell populations observed in the parent tumor. Moreover, SP cells had higher proliferation rates, were much less apoptotic compared to non-SP cells, and generated tumors more rapidly than non-SP cells. We also investigated the effects of interferon-alfa (IFN-alpha), a cytokine which has been widely used to treat solid tumors, on EOC cells and observed that IFN-alpha exerts marked anti-proliferative and pro-apoptotic effects on primary cultures containing SP cells. IFN-alfa-treatment invariably caused a dramatic reduction in SP size in tumor cell lines of different origin and in normal bone-marrow SP cells, associated with a distinctive transcriptional profile. Gene therapy with human IFN-alpha resulted in regression of established tumors bearing a large SP fraction, which was not observed when tumors bearing low SP levels were treated. These findings could have relevant clinical implications since they imply that tumors bearing large SP numbers - albeit rare - could be sensitive to IFN-alpha treatment. Experiment Overall Design: 4 Affymetrix microarrays: Experiment Overall Design: 2 technical replicates: Ovarian cancer, untreated Side Population, rep1 Experiment Overall Design: Ovarian cancer, untreated Side Population, rep2 Experiment Overall Design: + Experiment Overall Design: 2 technical replicates: Ovarian cancer, IFN-alpha treated Side Population, rep1 Experiment Overall Design: Ovarian cancer, IFN-alpha treated Side Population, rep2

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