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:We identified an endothelial progenitor/stem like population in the endothelial fraction of preexsiting blood vessels. And we used microarray to see the difference of gene expression profiles between these two populations. Hindlimb muscle of wild type C57BL/6 were digested to single cells and stained with anti-CD31 antibody, anti- CD45 antibody, Propidium iodide and hoechst 33342. CD31+CD45- side population cells and CD31+CD45- main population cells were sorted by flow cytometry for RNA extraction and hybridized on Affimetrix 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.
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.
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:Purpose: To explore the side population (SP) in pancreatic ductal adenocarcinoma (PDAC) for its gene expression profile and its association to cancer stem cells (CSC) and to evaluate the value of genes from its gene signature on patient survival. Experimental design: Side and main population (MP) cells were isolated from 11 human PDAC resection specimens using fluorescence-activated cell sorting (FACS) after Hoechst incubation. Total RNA was extracted for whole-genome analysis. A gene signature for the purified SP (pSP; depleted from immune/endothelial CD45+/CD31+ cells) was developed and validated with the nCounter system on expression data of 78 primary PDAC using Cox regression analyses for disease-free and overall survival. Results: An SP was identified in all PDAC samples. Whole-genome expression profiling of pSP revealed upregulation of genes related to therapy-resistance and of CSC-associated genes and pathways. A pSP signature of 32 up- or downregulated genes was capable of discriminating SP from MP in an independent set of 10 PDAC samples, and some contributing genes had a prognostic value in a separate series of 78 patients who underwent surgery for PDAC. Conclusion: Pancreatic cancer contains an SP with chemo-resistant and CSC-associated molecular characteristics. Genes from a newly defined pSP gene signature are related to survival of patients who undergo surgical resection for pancreatic cancer, and might therefore represent potential therapeutic targets. Microarray analysis was performed on SP and MP samples from 11 different human PDAC samples.
Project description:Purpose: To explore the side population (SP) in pancreatic ductal adenocarcinoma (PDAC) for its gene expression profile and its association to cancer stem cells (CSC) and to evaluate the value of genes from its gene signature on patient survival. Experimental design: Side and main population (MP) cells were isolated from 11 human PDAC resection specimens using fluorescence-activated cell sorting (FACS) after Hoechst incubation. Total RNA was extracted for whole-genome analysis. A gene signature for the purified SP (pSP; depleted from immune/endothelial CD45+/CD31+ cells) was developed and validated with the nCounter system on expression data of 78 primary PDAC using Cox regression analyses for disease-free and overall survival. Results: An SP was identified in all PDAC samples. Whole-genome expression profiling of pSP revealed upregulation of genes related to therapy-resistance and of CSC-associated genes and pathways. A pSP signature of 32 up- or downregulated genes was capable of discriminating SP from MP in an independent set of 10 PDAC samples, and some contributing genes had a prognostic value in a separate series of 78 patients who underwent surgery for PDAC. Conclusion: Pancreatic cancer contains an SP with chemo-resistant and CSC-associated molecular characteristics. Genes from a newly defined pSP gene signature are related to survival of patients who undergo surgical resection for pancreatic cancer, and might therefore represent potential therapeutic targets.
Project description:A subset of osteoblasts functions as a key component of the hematopoietic stem cell niche. But it is still unclear that the precise cellular and molecular contribution of endosteal cell populations on the HSC supportive microenvironment. We purified the endosteal cells and subdivided them into mesenchymal progenitor cells (MPCs: ALCAM(-)Sca-1(+)) and two osteoblast populations (ALCAM(-)Sca-1(-) and ALCAM(+)Sca-1(-)). In this study, to clarify the characteristics of these fractionated cells in detail, gene expression analysis were performed using the GeneChip Mouse Genome Array 430 2.0 (Affymetrix). The bone fragments of femur and tibiae were treated with collagenase and endosteal cells were obtained. For enrichment of non-hematopoietic and non-endothelial population, CD45(-)CD31(-)Ter119(-) population was isolated and then the expressions of Sca-1 and activated leukocyte cell adhesion molecule (ALCAM) was analyzed by FACS. FACS analysis showed that CD45(-)CD31(-)Ter119(-) cells were subdivided into ALCAM(-)Sca-1(+), ALCAM(-)Sca-1(-) and ALCAM(+)Sca-1(-). These three populations were sorted and RNA samples were used for amplification, labeling, and hybridization to independent arrays.