Proteomic differential display analysis identified upregulated astrocytic phosphoprotein PEA‐15 in human malignant pleural mesothelioma cell lines

Abstract

We performed proteomic differential display analysis of human malignant pleural mesothelioma (MPM) cell lines and a human pleural mesothelial cell line by using 2-DE and LC-MS/MS. The human MPM cell lines were NCI-H28, NCI-H2052 and NCI-H2452, and the human pleural mesothelial cell line was MeT-5A. Between MeT-5A and NCI-H2052, we found 38 protein spots whose expression levels were different, from the results of 2-DE; 28 protein spots appeared higher, and 10 other protein spots lower in NCI-H2052 than in MeT-5A. These spots were analyzed by LC-MS/MS analysis and identified by a peptide sequence tag. However, from the results of 2-DE of the other cell lines, there was only one consistently upregulated protein, astrocytic phosphoprotein PEA-15, in all three MPM cell lines. Western blotting using specific antibodies against PEA-15 confirmed the elevated expression level of PEA-15 in all three MPM cell lines compared with MeT-5A cells and normal pleura tissues from patients. PEA-15 was knocked down in NCI-H2052 cells, and the proliferation of PEA-15-silenced NCI-H2052 cells was suppressed 7-15% compared with negative control cells. These results suggest that PEA-15 expression is likely to be associated with the tumorigenesis of MPM.

Phosphorylation is the switch that turns PEA-15 from tumor suppressor to tumor promoter

“…16,17,19 On the other hand PEA-15 is highly expressed in certain human glioblastomas and human malignant pleural mesotheliomas, both late stage malignancies with a poor prognosis. 28,29 The key to evaluating PEA-15's function on a molecular level therefore lies beyond its expression levels and has to include other post-translational factors that determine its effects on tumor growth and metastasis.…”

RipAY, a Plant Pathogen Effector Protein, Exhibits Robust γ-Glutamyl Cyclotransferase Activity When Stimulated by Eukaryotic Thioredoxins

“…In-gel digestion and the following LC-MS/MS analysis of the activator protein from yeast were performed as described previously (26). Protein identification was performed in the Agilent Spectrum MILL MS proteomics workbench against the Swiss-Prot protein database search engine.…”

Differential expression of up-regulated cofilin-1 and down-regulated cofilin-2 characteristic of pancreatic cancer tissues

“…Using proteomic differential display analysis, research groups have identified biomarkers such as PEA-15 in human malignant pleural mesothelioma cell lines, heat-shock proteins (Hsp27, Hsp70, GRP78) in hepatocellular carcinoma, numerous candidate proteins in colorectal cancer and α-1-antitrypsin isoforms as a possible serum biomarker in pancreatic cancer (2)(3)(4)(5)(6). Proteomic technology that combines two-dimensional gel electrophoresis (2-DE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) has high throughput and accuracy, and these technologies are considered as useful tools to comprehensively analyze proteins.…”