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Acquisition of a side population fraction through downregulation of MSL3, ZNF691, VPS45, ITGB3BP, TLE2, and ZNF498 augments malignant phenotype in ovarian cancer.

ABSTRACT: Side population (SP) cells harbor malignant phenotypes, such as sphere forming capacity, single cell clonogenicity and in vivo tumorigenicity. These malignant phenotypes are related to a poor prognosis for women with ovarian cancer. The aim of this study was to identify key factor(s) that increase the proportion of ovarian cancer SP cells through a functional genomics screen. A library of 81 000 shRNAs targeting 15 000 genes was transfected into CH1 and SKOV3 cells, followed by SP analysis. We found that suppression of MSL3, ZNF691, VPS45, ITGB3BP, TLE2, and ZNF498 markedly increased the proportion of SP cells. Newly generated SP cells exhibit significantly greater capacity for sphere formation, single cell clonogenicity, and in vivo tumorigenicity. On the contrary, overexpression of MSL3, VPS45, ITGB3BP, TLE2, and ZNF498 significantly decreased the proportion of SP cells, sphere formation capacity and single cell clonogenicity. In ovarian cancer cases, low expression of MSL3, ZNF691 and VPS45 was related to poor prognosis. Suppression of these six genes tended to increase some stem cell-related pathways, and significantly enhanced activity of the hedgehog pathway. Cyclopamine, a hedgehog pathway inhibitor, significantly decreased the number of newly generated SP cells and their sphere forming ability. Our results provide new information regarding molecular mechanisms favoring SP cells and suggest that Hedgehog signaling may provide a viable target for improving ovarian cancer survival.

ORGANISM(S): Homo sapiens

PROVIDER: GSE117480 | GEO | 2018/07/24

REPOSITORIES: GEO

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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.

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Acquisition of a side population fraction through downregulation of MSL3, ZNF691, VPS45, ITGB3BP, TLE2, and ZNF498 augments malignant phenotype in ovarian cancer.

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