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1.
Proteomics Clin Appl ; 7(9-10): 677-89, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23775902

ABSTRACT

PURPOSE: Using prostatic fluids rich in glycoproteins like prostate-specific antigen and prostatic acid phosphatase (PAP), the goal of this study was to identify the structural types and relative abundance of glycans associated with prostate cancer status for subsequent use in emerging MS-based glycopeptide analysis platforms. EXPERIMENTAL DESIGN: A series of pooled samples of expressed prostatic secretions (EPS) and exosomes reflecting different stages of prostate cancer disease were used for N-linked glycan profiling by three complementary methods, MALDI-TOF profiling, normal-phase HPLC separation, and triple quadropole MS analysis of PAP glycopeptides. RESULTS: Glycan profiling of N-linked glycans from different EPS fluids indicated a global decrease in larger branched tri- and tetra-antennary glycans. Differential exoglycosidase treatments indicated a substantial increase in bisecting N-acetylglucosamines correlated with disease severity. A triple quadrupole MS analysis of the N-linked glycopeptides sites from PAP in aggressive prostate cancer pools was done to cross-reference with the glycan profiling data. CONCLUSION AND CLINICAL RELEVANCE: Changes in glycosylation as detected in EPS fluids reflect the clinical status of prostate cancer. Defining these molecular signatures at the glycopeptide level in individual samples could improve current approaches of diagnosis and prognosis.


Subject(s)
Acetylglucosamine/metabolism , Disease Progression , Glycoproteins/chemistry , Glycoproteins/metabolism , Polysaccharides/metabolism , Prostate/metabolism , Prostatic Neoplasms/metabolism , Glycomics , Humans , Male , Neoplasm Grading , Polysaccharides/chemistry , Prostatic Neoplasms/pathology
2.
J Proteomics ; 72(6): 907-17, 2009 Aug 20.
Article in English | MEDLINE | ID: mdl-19457353

ABSTRACT

The prostate gland secretes many proteins in a prostatic fluid that combines with seminal vesicle derived fluids to promote sperm activation and function. Proximal fluids of the prostate that can be collected clinically are seminal plasma and expressed-prostatic secretion (EPS) fluids. EPS represents the fluid being secreted by the prostate following a digital rectal prostate massage, which in turn can be collected in voided urine post-exam. This collection is not disruptive to a standard urological exam, and it can be repeatedly collected from men across all prostatic disease states. A direct EPS fluid can also be collected under anesthesia prior to prostatectomy. While multiple genetic assays for prostate cancer detection are being developed for the shed epithelial cell fraction of EPS urines, the remaining fluid that contains many prostate-derived proteins has been minimally characterized. Approaches to optimization and standardization of EPS collection consistent with current urological exam and surgical practices are described, and initial proteomic and glycomic evaluations of the of EPS fluid are summarized for prostate specific antigen and prostatic acid phosphatase. Continued characterization of the prostate specific protein components of EPS urine combined with optimization of clinical collection procedures should facilitate discovery of new biomarkers for prostate cancer.


Subject(s)
Gene Expression Regulation, Neoplastic , Prostate/metabolism , Prostatic Diseases/diagnosis , Prostatic Neoplasms/diagnosis , Proteomics/methods , Acid Phosphatase , Biomarkers/metabolism , Body Fluids , Electrophoresis, Gel, Two-Dimensional , Epithelial Cells/cytology , Glycomics/methods , Humans , Male , Prostatic Diseases/metabolism , Prostatic Diseases/urine , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/urine , Protein Tyrosine Phosphatases/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Time Factors
3.
J Proteome Res ; 8(2): 620-30, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19128049

ABSTRACT

Prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) are glycoproteins secreted by prostate epithelial cells, and have a long clinical history of use as serum biomarkers of prostate cancers. These two proteins are present at significantly higher concentrations in seminal plasma, making this proximal fluid of the prostate a good source for purifying enough protein for characterization of prostate disease associated changes in glycan structures. With the use of seminal fluid samples representative of normal control, benign prostatic disease and prostate cancers, PAP and PSA were enriched by thiophilic absorption chromatography. Released N-linked glycan constituents from both proteins were analyzed by a combination of normal phase HPLC and MALDI-TOF spectrometry. For PSA, 40 putative glycoforms were determined, and 21 glycoforms were determined for PAP. PAP glycans were further analyzed with a hybrid triple quadrupole/linear ion trap mass spectrometer to assign specific glycoform classes to each of the three N-linked sites. The glycans identified in these studies will allow for more defined targeting of prostate disease-specific changes for PAP, PSA and other secreted prostatic glycoproteins.


Subject(s)
Glycomics/methods , Prostate-Specific Antigen , Prostatic Neoplasms/blood , Protein Tyrosine Phosphatases , Semen , Acid Phosphatase , Biomarkers, Tumor/blood , Biomarkers, Tumor/chemistry , Carbohydrate Conformation , Carbohydrate Sequence , Humans , Male , Molecular Sequence Data , Polysaccharides/analysis , Prostate-Specific Antigen/blood , Prostate-Specific Antigen/chemistry , Prostatic Neoplasms/chemistry , Prostatic Neoplasms/enzymology , Protein Tyrosine Phosphatases/blood , Protein Tyrosine Phosphatases/chemistry , Semen/chemistry , Semen/enzymology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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