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.
"PEA-15 is known to be upregulated in a variety of cancer subsets including immortal cancer cell lines (e.g. MCF-7 and HeLa cells) (Condorelli et al., 1999), malignant pleural mesothelioma cells (Kuramitsu et al., 2009), breast cancer cells (Stassi et al., 2005), non-small cell lung cancer (NSCLC) cells (Zanca et al., 2008), glioblastoma (Eramo et al., 2005) and renal cell carcinomas (Heikaus et al., 2008). Mice overexpressing PEA-15 also displayed an increase in skin tumourigenesis with a four-fold increase in papilloma number compared to their wild type littermates (Formisano et al., 2005), suggesting a potential role for PEA-15 in tumour formation and cancer progression. "
[Show abstract][Hide abstract] ABSTRACT: Phosphoprotein enriched in astrocytes-15 (PEA-15) is a cytoplasmic protein that sits at an important junction in intracellular signalling and can regulate diverse cellular processes, such as proliferation and apoptosis, dependent upon stimulation. Regulation of these processes occurs by virtue of the unique interaction of PEA-15 with other signalling proteins. PEA-15 acts as a cytoplasmic tether for the mitogen-activated protein kinases, extracellular signal-regulated kinase 1/2 (ERK1/2) preventing nuclear localisation. In order to release ERK1/2, PEA-15 requires to be phosphorylated via several potential pathways. PEA-15 (and its phosphorylation state) therefore regulates many ERK1/2-dependent processes, including proliferation, via regulating ERK1/2 nuclear translocation. In addition, PEA-15 contains a death effector domain (DED) which allows interaction with other DED-containing proteins. PEA-15 can bind the DED-containing apoptotic adaptor molecule, Fas-associated death domain protein (FADD) which is also dependent on the phosphorylation status of PEA-15. PEA-15 binding of FADD can inhibit apoptosis as bound FADD cannot participate in the assembly of apoptotic signalling complexes. Through these protein-protein interactions, PEA-15-regulated cellular effects have now been investigated in a number of disease-related studies. Changes in PEA-15 expression and regulation have been observed in diabetes mellitus, cancer, neurological disorders and the cardiovascular system. These changes have been suggested to contribute to the pathology related to each of these disease states. As such, new therapeutic targets based around PEA-15 and its associated interactions are now being uncovered and could provide novel avenues for treatment strategies in multiple diseases.
"These findings were supported by a previous report that single-agent erlotinib therapy had no efficacy in a phase II clinical trial involving patients with MPM . Kuramitsu et al. also investigated therapeutic targets using a proteomic approach . Overexpression of the astrocytic phosphoprotein PEA-15 was identified in MPM cell lines in a comparative study of normal pleural and MPM cell lines by 2D-PAGE. "
[Show abstract][Hide abstract] ABSTRACT: Soft tissue sarcomas are rare and account for less than 1% of all malignant cancers. Other than development of intensive therapies, the clinical outcome of patients with soft tissue sarcoma remains very poor, particularly when diagnosed at a late stage. Unique mutations have been associated with certain soft tissue sarcomas, but their etiologies remain unknown. The proteome is a functional translation of a genome, which directly regulates the malignant features of tumors. Thus, proteomics is a promising approach for investigating soft tissue sarcomas. Various proteomic approaches and clinical materials have been used to address clinical and biological issues, including biomarker development, molecular target identification, and study of disease mechanisms. Several cancer-associated proteins have been identified using conventional technologies such as 2D-PAGE, mass spectrometry, and array technology. The functional backgrounds of proteins identified were assessed extensively using in vitro experiments, thus supporting expression analysis. These observations demonstrate the applicability of proteomics to soft tissue sarcoma studies. However, the sample size in each study was insufficient to allow conclusive results. Given the low frequency of soft tissue sarcomas, multi-institutional collaborations are required to validate the results of proteomic approaches.
"Although these immunohistochemical biomarkers may help in the differential diagnosis of MPM to some degree, novel biomarkers with higher sensitivity and specificity have also been long required. Proteomic studies on MPM conducted to date have used tissue microarray samples , plasma samples, pleural effusions  and cell lines     , none however, has used direct protein extracts from surgical specimens of MPM, probably because MPM has a complex histology and clinical materials are difficult to obtain. "
[Show abstract][Hide abstract] ABSTRACT: To investigate the proteomic background of malignancies of the pleura, we examined and compared the proteomic profile of malignant pleural mesothelioma (MPM)(10 cases), lung adenocarcinoma (11 cases), squamous cell carcinoma of the lung (13 cases), pleomorphic carcinoma of the lung (3 cases) and synovial sarcoma (6 cases). Cellular proteins were extracted from specific populations of tumor cells recovered by laser microdissection. The extracted proteins were labeled with CyDye DIGE Fluor saturation dyes and subjected to two-dimensional difference gel electrophoresis (2D-DIGE) using a large format electrophoresis device. Among 3875 protein spots observed, the intensity of 332 was significantly different (Wilcoxon p value less than 0.05) and with more than two-fold inter-sample-group average difference between the different histology groups. Among these 332, 282 were annotated by LC-MS/MS and included known biomarker proteins for MPM, such as calretinin, as well as proteins previously uncharacterized in MPM. Tissue microarray immunohistochemistry revealed that the expression of cathepsin D was lower in MPM than in lung adenocarcinoma (15% vs. 44% of cases respectively in immunohistochemistry). In conclusion, we examined the protein expression profile of MPM and other lung malignancies, and identified cathepsin D to distinguish MPM from most popular lung cancer such as lung adenocarcinoma.
Journal of proteomics 10/2011; 75(3):833-44. DOI:10.1016/j.jprot.2011.09.026 · 3.89 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.