Results

RDF/XMLNTriplesTurtleShow queryShare ▶
SubjectPredicateObject
http://purl.uniprot.org/citations/20651337http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/20651337http://www.w3.org/2000/01/rdf-schema#comment"

Background

Protein phosphorylation is one of the essential steps in cell signaling, and aberrant phosphorylation is a common event in human cancer. The expression of receptor type protein tyrosine phosphatase gamma (PTPRG) in normal breast is found to be approximately 50-60% higher than that of breast tumor tissue. Overexpression of PTPRG inhibits anchorage-independent growth and proliferation of breast cancer cells. To understand the tumor suppression characteristics of PTPRG, we studied its tumor suppressive function in an athymic mouse model and evaluated factors that can potentially regulate its expression in breast cancer cells.

Materials and methods

To investigate the function of PTPRG in vivo, athymic nude mice were implanted with MCF-7 cells overexpressing PTPRG. For in vitro study, protein levels of cell cycle regulators, cell cycle re-entry, and the phosphorylation levels of extracellular signal-regulated protein kinases 1/2 (ERK1/2) were examined. In addition, methylation assays were conducted to investigate the epigenetic modification on the promoter of PTPRG.

Results

Athymic nude mice bearing MCF-7 cells overexpressing PTPRG showed a reduction in tumor burden in comparison to animals implanted with MCF-7 cells transfected with vector alone. When these two cell lines were studied in an in vitro system, elevated mRNA and protein levels of cell cycle regulators, p21(cip) and p27(kip) were detected in MCF-7 cells overexpressing PTPRG compared to cells transfected with vector alone. Similarly, overexpression of PTPRG also delayed the re-entry of breast cancer cells into the cell cycle after serum starvation, and reduced the phosphorylation levels ERK1/2 in MCF-7 cells. In addition, methylation assays in PTPRG promoter in breast cancer cell lines (including SK-Br-3) revealed an aberrant methylation pattern. When SK-Br-3 and MCF-7 cells were treated with deoxy-5-azacytidine (DAC) and trichostatin A (TSA), these compounds reactivated the expression of PTPRG, suggesting an epigenetic control on its expression.

Conclusion

Our results indicated that PTPRG inhibited breast tumor formation in vivo; PTPRG may up-regulate p21(cip) and p27(kip) proteins through the ERK1/2 pathway. This study also showed methylation-mediated silencing of PTPRG in breast cancer cell lines. These data indicate that PTPRG exhibits the characteristics of a breast tumor suppressor."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Huang Y.W."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Liu S."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Lin Y.C."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Yan P."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Ye W."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Sugimoto Y."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Wang L.S."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Chang H.L."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/author"Shu S.T."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/date"2010"xsd:gYear
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/name"Anticancer Res"xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/pages"1937-1946"xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/title"Function and regulatory mechanisms of the candidate tumor suppressor receptor protein tyrosine phosphatase gamma (PTPRG) in breast cancer cells."xsd:string
http://purl.uniprot.org/citations/20651337http://purl.uniprot.org/core/volume"30"xsd:string
http://purl.uniprot.org/citations/20651337http://www.w3.org/2004/02/skos/core#exactMatchhttp://purl.uniprot.org/pubmed/20651337
http://purl.uniprot.org/citations/20651337http://xmlns.com/foaf/0.1/primaryTopicOfhttps://pubmed.ncbi.nlm.nih.gov/20651337
http://purl.uniprot.org/uniprot/#_A9QVW2-mappedCitation-20651337http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/20651337
http://purl.uniprot.org/uniprot/#_B7Z3T1-mappedCitation-20651337http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/20651337
http://purl.uniprot.org/uniprot/#_Q86TJ8-mappedCitation-20651337http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/20651337
http://purl.uniprot.org/uniprot/#_L8E7E6-mappedCitation-20651337http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/20651337
http://purl.uniprot.org/uniprot/#_O60420-mappedCitation-20651337http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/20651337
http://purl.uniprot.org/uniprot/#_P23470-mappedCitation-20651337http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/20651337
http://purl.uniprot.org/uniprot/#_Q49A02-mappedCitation-20651337http://www.w3.org/1999/02/22-rdf-syntax-ns#objecthttp://purl.uniprot.org/citations/20651337
▶