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Expression data from three human cancer cell lines (PC-3, SK-OV-3, WM793B) exposed to experimental cycling and chronic hypoxa in vitro

ABSTRACT: One of the most important features of tumor microenvironment, imposing adverse effect on patient prognosis, is low oxygen tension. There are two types of hypoxia that may occur within tumor mass: chronic and cycling. Preliminary studies point at cycling hypoxia as being more relevant in induction of aggressive phenotype of tumor cells and radioresistance though little is known about the molecular mechanism of this phenomenon. Analysis of gene expression profile of human prostate (PC-3), ovarian (SK-OV-3) and melanoma (WM793B) cancer cells to expermental cycling (interchanging conditions of 1% and 21% oxygen) or chronic (1% oxygen) for 72 hours. Gene expression profiles were analyzed using U133 Plus 2.0 Array (Affymetrix) oligonucleotide microarrays. Data analysis revealed that globally gene expression profiles induced by the two types of hypoxia are similar and they strongly depend on the cell type.However, cycling hypoxia changes expression of lower number of genes in comparison to chronic one ( 3767 vs. 5954 probesets (p<0.001)) and to lower extent (lower fold changes). Analysis of hypoxia-regulated gene lists obtained using Random Variance Model t-test identified 253 probe sets (FC>2, p<0.001) common to all three cell lines, though no universal (changed throughout all analyzed cell lines) genes specifically influanced only by cycling hypoxia was selected. On the other hand, we identified such genes within particular one or two cell lines. Among them those related with EGF pathway seemed to be overrepresented (i.e. EPHA2, AREG, and HBEGF) and together with PLAU and IL-8 were mostly validated by Q-PCR. We investigated transcriptional activity of prostate and ovarian cancer cells as well as melanoma cells cultured for 72h under chronic hypoxic (nominal 1% oxygen; 3 experimental samples for each cell type), cycling hypoxia (interchanging periods of nominal 1% and 21% oxygen; 3 samples for each line) and control conditions (21% oxygen; 3 samples for each cell lines).

ORGANISM(S): Homo sapiens

SUBMITTER: Olbryt Magdalena

PROVIDER: S-ECPF-GEOD-53012 | biostudies-other |

REPOSITORIES: biostudies-other

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Project description:One of the most important features of tumor microenvironment, imposing adverse effect on patient prognosis, is low oxygen tension. There are two types of hypoxia that may occur within tumor mass: chronic and cycling. Preliminary studies point at cycling hypoxia as being more relevant in induction of aggressive phenotype of tumor cells and radioresistance though little is known about the molecular mechanism of this phenomenon. Analysis of gene expression profile of human prostate (PC-3), ovarian (SK-OV-3) and melanoma (WM793B) cancer cells to expermental cycling (interchanging conditions of 1% and 21% oxygen) or chronic (1% oxygen) for 72 hours. Gene expression profiles were analyzed using U133 Plus 2.0 Array (Affymetrix) oligonucleotide microarrays. Data analysis revealed that globally gene expression profiles induced by the two types of hypoxia are similar and they strongly depend on the cell type.However, cycling hypoxia changes expression of lower number of genes in comparison to chronic one ( 3767 vs. 5954 probesets (p<0.001)) and to lower extent (lower fold changes). Analysis of hypoxia-regulated gene lists obtained using Random Variance Model t-test identified 253 probe sets (FC>2, p<0.001) common to all three cell lines, though no universal (changed throughout all analyzed cell lines) genes specifically influanced only by cycling hypoxia was selected. On the other hand, we identified such genes within particular one or two cell lines. Among them those related with EGF pathway seemed to be overrepresented (i.e. EPHA2, AREG, and HBEGF) and together with PLAU and IL-8 were mostly validated by Q-PCR. We investigated transcriptional activity of prostate and ovarian cancer cells as well as melanoma cells cultured for 72h under chronic hypoxic (nominal 1% oxygen; 3 experimental samples for each cell type), cycling hypoxia (interchanging periods of nominal 1% and 21% oxygen; 3 samples for each line) and control conditions (21% oxygen; 3 samples for each cell lines).

Project description:Metastatic colonization involves cancer cell lodgment or adherence in the microvasculature and subsequent migration of those cells across the endothelium into a secondary organ site. To study this process further, we analyzed transendothelial migration of human PC-3 prostate cancer cells in vitro. We isolated a subpopulation of cells, TEM4-18, that crossed an endothelial barrier more efficiently, but surprisingly, were less invasive than parental PC-3 cells in other contexts in vitro. Importantly, TEM4-18 cells were more aggressive than PC-3 cells in a murine metastatic colonization model. Microarray and FACS analysis of these cells showed that the expression of many genes previously associated with leukocyte trafficking and cancer cell extravasation were either unchanged or down-regulated. TEM4-18 cells exhibited characteristic molecular markers of an epithelial-to-mesenchymal transition (EMT), including frank loss of E-cadherin expression and upregulation of the E-cadherin repressor ZEB1. Silencing ZEB1 in TEM4-18 cells resulted in increased E-cadherin and reduced transendothelial migration. TEM4-18 cells also express N-cadherin, which was found to be necessary, but not sufficient for increased transendothelial migration. Our results extend the role of EMT in metastasis to transendothelial migration and implicate ZEB1 and N-cadherin in this process in prostate cancer cells. Experiment Overall Design: We wanted to compare the expression profiles of cells that had undergone transendothelial migration. The parental, and reference cell line, PC-3 was plated onto a confluent human microvascular endothelial cell line from the lung and allowed to migrate across this monolayer. A new cell line, TEM4-18, was isolated from this experiment. We also performed this experiment a second time to isolate a biological replicate of the TEM4-18 cell line, termed TEM2-5. All 3 cell lines, PC-3, TEM4-18, and TEM2-5 are analyzed as replicates in this experiment for a total of 6 samples in this microarray. Both TEM4-18 and TEM2-5 were then compared to PC-3 cells for changes in gene expression.

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Expression data from three human cancer cell lines (PC-3, SK-OV-3, WM793B) exposed to experimental cycling and chronic hypoxa in vitro

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