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Recent research has identified many genes and proteins that play specific roles in the process of systemic metastasis in various types of cancer. Rho GDP dissociation inhibitor 2 (RhoGDI2) has been shown to inhibit metastasis in human bladder cancer, but its role in breast cancer is controversial.
We examined the regulation and clinical significance of RhoGDI2 in Korean breast cancer patients by using proteomic approaches.
By using a proteomic approach, we observed an increased expression of RhoGDI2 in human breast cancer tissues when compared to that of the normal breast tissues, and we validated its up-regulation in an independent cohort of 8 breast cancer patients. The clinical implication of a RhoGDI2 expression was investigated in 57 breast cancer patients by performing immunohistochemistry. RhoGDI2 did not show a significant association with the tumor size, lymph node metastasis, the histologic grade or the hormone receptor status. However, the patients with RhoGDI2-expressing tumors had significantly shorter disease-free survival (p=0.043; hazard ratio, 3.87) and distant metastasis-free survival (p=0.039; hazard ratio, 5.15).
Our results demonstrated a potential role of RhoGDI2 as a poor prognostic marker as well as a potential therapeutic target. The pro-metastatic nature of RhoGDI2 shown in our study may indicate its organ-specific role in cancer metastasis.
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Radiation-induced pulmonary fibrosis (RIF) is a significant complication of radiotherapy for lung cancer. Despite the large number of studies, the molecular mechanisms of RIF are poorly understood. Therefore, the complex protein expression pattern in RIF was characterized by identifying the proteins with an altered expression level after thorax irradiation using two-dimensional electrophoresis (2-DE) and mass spectrometry.
A mouse model of RIF was used to examine the alteration of the lung proteome because of availability of murine data related to human cases and the abundance of murine fibrotic lung samples. A mouse model of RIF was induced in radiosensitive C57BL/6 mice. Twenty-one weeks after 25 Gy irradiation, hematoxylin-eosin staining and hydroxyproline assay confirmed the early-phase pulmonary fibrosis.
Lung samples from the irradiated and age-matched control mice were used to generate 16 high quality 2-DE gels containing approximately 1,000 spots. Of the 31 significantly up- or down-regulated protein spots, 17 were identified by MALDI-TOF/MS.
Two important upregulated proteins were found, the α1-protease inhibitor and galectin-1, which might be used as potential markers for the early phase of RIF.
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Cervical cancer is one of the leading world causes of cancer morbidity and mortality in woman, with more than 98% related to a human papillomavirus (HPV) infection origin. Infection with specific subtypes of HPV has been strongly implicated in cervical carcinogenesis. The identification and functional verification of host proteins associated with HPV E6 and E7 oncoproteins may provide useful information in understanding cervical carcinogenesis and the development of cervical cancer-specific markers. The advent of functional genomics and proteomics has provided hope of discovering novel biological markers for use in the screening, early diagnosis, prognostication and prediction of response to therapy. Herein, we review the studies where the profiles of host proteins associated with HPV E6 and E7 oncoproteins in cervical cancer were generated.
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Pancreatic cancer has a poor prognosis, due in part to the lack of an effective approach for its early detection. The identification of tumor antigens potentially provides a means for the early diagnosis. The purpose of this study was to use a proteomic approach for the identification of proteins that commonly induce a humoral response in patients with pancreatic cancer.
Proteins from the pancreatic adenocarcinoma cell line, BxPC3, were subjected to two-dimensional polyacrylamide gel electrophoresis, followed by Western blot analysis, where individual sera were tested for autoantibodies. Sera from 36 patients with pancreatic adenocarcinoma, and 68 from control groups (14 from lung adenocarcinoma, 19 from colon adenocarcinoma and 35 from healthy subjects) were analyzed. CLP36 expression was evaluated by immunohistochemical analysis and real-time PCR. The cellular localization of CLP36 as an autoantigen was investigated by Western blot analysis.
The autoantibody was detected against a protein, identified by mass spectrometry as CLP36, in 14 of the 36 sera (38.9%) from patients with a pancreatic adenocarcinoma, and 3 of the 68 controls (4.4%). Immunohistochemical analysis of CLP36 in a tissue array demonstrated diffuse and consistent immunoreactivity in the pancreatic adenocarcinomas. The levels of CLP36 mRNA were highest in the pancreatic cancer cell lines of the different cells analyzed. The molecular weight of the protein displayed in the membrane-rich fraction was larger than that in the cytosolic fraction, which is likely attributable to a post-translational modification.
CLP36 was identified as a tumor autoantigen inducing a humoral immune response in pancreatic adenocarcinomas. More detailed studies need to be undertaken to understand whether the humoral response by CLP36 is tumor-specific.
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It is well known that infection with HPV (human papillomavirus) is the main cause of cervical cancer and certain types of HPV are recognized as carcinogens. At present, there is little information regarding the antineoplastic mechanism of paclitaxel against cervical carcinoma cells. We thus tried to analyze differential protein expression and antineoplastic mechanism-related proteins after paclitaxel treatment on cervical cancer cells by using a proteomic analysis and to investigate the mechanism of action.
Using proteomics analysis including 2-DE and MALDI-TOF-MS, we detected the antineoplastic mechanism-related proteins. Then, we performed western blot analysis for apoptosis- and transformation-related proteins to confirm expression patterns derived from proteome analysis after paclitaxel treatment.
We identified several cellular proteins that are responsive to paclitaxel treatment in HeLa cells using proteomics methods. Paclitaxel treatment elevated mainly apoptosis, immune response and cell cycle check point-related proteins. On the other hand, paclitaxel treatment diminished growth factor/oncogene-related proteins and transcription regulation-related proteins. Also, in the HPV-associated cervical carcinoma cells, paclitaxel demonstrated anti-proliferative activity through the membrane death receptor-mediated apoptotic pathway and the mitochondrial-mediated pathway.
Identification and characterization of functionally modulated proteins involved in anti-cancer regulatory events should lead to a better understanding of the long-term actions of paclitaxel at the molecular level and will contribute to the future development of novel therapeutic drug treatments based upon current therapies.
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This study utilized both cDNA microarray and 2D protein gel electrophoresis technology to investigate the multiple interactions of the genes and proteins involved in the pathophysiology of uterine leiomyomas. Also, Gene Ontology (GO) analysis was used to systematically characterize the global expression profiles, which were found to correlate with the leiomyosarcomas.
The uterine leiomyoma biopsies were obtained from patients in the Department of Obstetrics and Gynecology, The Catholic University of Korea. Differentially expressed transcriptome and proteome, in 6 paired leiomyoma and normal myometrium, were profiled. The total RNAs from the leiomyoma and normal myometrium were labeled with Cy5 and Cy3. All specimens were punch-biopsy-obtained, and frozen in liquid nitrogen.
Screening of up to 17,000 genes identified 71 that were either up-regulated or down-regulated (21 and 50, respectively). The gene expression profiles were classified into 420 mutually dependent functional sets, resulting in 611 cellular processes, according to the gene ontology. Also, the protein analysis, using 2D gel electrophoresis, identified 33 proteins (17 up-regulated and 16 down-regulated) with more than 500 total spots, which were classified into 302 cellular processes. O f these functional profilings, transcriptomes and proteoms down-regulations were shown in the cell adhesion, cell m otility, organogenesis, enzyme regulator, structural molecule activity and responses to external stimulus functional activities, which are supposed to play important roles in the pathophysiology. In contrast, up-regulation was only shown in the nucleic acid binding activity. The CDKN2A, ADH1A, DCX, IGF2, CRABP2 and KIF5C were found to increase the reliability of this study, and correlate with the leiomyosarcomas.
Potentially significant pathogenetic cellular processes showed that down-regulated functional profiling has an important impact on the discovery of the pathogenic pathways in leiomyomas and leiomyosarcomas. GO analysis can also overcome the complexity of the expression profiles of cDNA microarrays and 2D protein analyses, via a cellular process level approach. Thereby, a valuable prognostic candidate gene, with real relevance to disease-specific pathogenesis, can be found at cellular process levels.
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