We recently showed that protein expression profiling of serum using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) has potential as a diagnostic approach for detection of prostate cancer. As a parallel effort, we have been pursuing the identification of the protein(s) comprising the individual discriminatory "peaks" and evaluating their utility as potential biomarkers for prostate disease.
We employed liquid chromatography, gel electrophoresis and tandem mass spectroscopy to isolate and identify a protein that correlates with observed SELDI-TOF MS mass/charge (m/z) values. Immunodepletion, immunoassay, and Western analysis were used to verify that the identified protein generated the observed SELDI peak. Subsequent immunohistochemistry was used to examine the expression of the proteins in prostate tumors.
An 8,946 m/z SELDI-TOF MS peak was found to retain discriminatory value in each of two separate data sets with an increased expression in the diseased state. Sequence identification by liquid chromatography-MS/MS and subsequent immunoassays verified that an isoform of apolipoprotein A-II (ApoA-II) is the observed 8,946 m/z SELDI peak. Immunohistochemistry revealed that ApoA-II is overexpressed in prostate tumors. SELDI-based immunoassay revealed that an 8.9-kDa isoform of ApoA-II is specifically overexpressed in serum from individuals with prostate cancer. ApoA-II was also overexpressed in the serum of individuals with prostate cancer who have normal prostate-specific antigen (0-4.0 ng/mL).
We have identified an isoform of ApoA-II giving rise to an 8.9K m/z SELDI "peak" that is specifically overexpressed in prostate disease. The ability of ApoA-II to detect disease in patients with normal prostate-specific antigen suggests potential utility of the marker in identifying indolent disease.
"Fragments of structural proteins can be detected in serum as the reflection of cartilage
degeneration. Numerous studies have reported the discovery of putative biomarkers in blood
using a mass spectrometer7, 8). There are three commonly used serum biomarkers associated
and/or correlated with OA and joint progression: antigenic keratin sulfate (AgKS)9), hyaluronan (HA)10, 11), and cartilage
oligomeric matrix protein (COMP)12). "
[Show abstract][Hide abstract] ABSTRACT: [Purpose] To investigate the correlation between the effect treadmill exercise and change in serum proteins in rats with osteoarthritis, a study of proteins was carried out using a mass spectrometer. [Subjects and Methods] Rats were randomly divided into five groups. After 4 weeks of treadmill training, serum from each rat was analyzed by Liquid chromatography-electrospray ionization tandem mass spectrometry. Complementary component 9 (C9) was discovered to be downregulated in the serum of the exercise groups, and this was validated by Western blot. [Results] Seventeen proteins were discovered to be elevated in the monosodium iodoacetate injection osteoarthritis group samples by more than 1.5 fold compared with the control group. One of the proteins upregulated, C9 protein, was validated, and it was found to decrease in the middle-intensity exercise group. [Conclusion] We showed that the serum level of C9, an inflammatory-related protein, decreased after treadmill exercise. Therefore, treadmill exercise with an appropriate intensity might be recommended for OA patients.
"13748.8Da were then chosen to set up the decision tree 24-25 (Figure 5). At Node l, samples of m/z 9180.5 with peak intensities lower than or equal to 6.28 went to terminal Node 1, which had 45 healthy volunteer. "
[Show abstract][Hide abstract] ABSTRACT: The aim of present study is to study the serum protein fingerprint of patients with colorectal cancer (CRC) and to screen protein molecules that are closely related to colorectal cancer during the onset and progression of the disease with Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Serum samples from 144 patients with CRC and 120 healthy volunteers were adopted in present study. Weak cation exchange (WCX) magnetic beads and PBSII-C protein chips reader (Ciphergen Biosystems Ins.) were used. The protein fingerprint expression of all the Serum samples and the resulted profiles between cancer and normal groups were analyzed with Biomarker Wizard system. Several proteomic peaks were detected and four potential biomarkers with different expression profiles were identified with their relative molecular weights of 2870.7 Da, 3084 Da, 9180.5 Da, and 13748.8 Da, respectively. Among the four proteins, two proteins with m/z 2870.7 and 3084 were down-regulated, and the other two with m/z 9180.5 and 13748.8 were up-regulated in serum samples from CRC patients. The present diagnostic model could distinguish CRC from healthy controls with the sensitivity of 92.85% and the specificity of 91.25%. Blind test data indicated a sensitivity of 86.95% and a specificity of 85%. The result suggested that MALDI technology could be used to screen critical proteins with differential expression in the serum of CRC patients. These differentially regulated proteins were considered as potential biomarkers for the patients with CRC in the serum and of the potential value for further investigation.
International journal of medical sciences 01/2011; 8(1):39-47. · 2.00 Impact Factor
"In addition, the abnormal expression of liver enrichment genes in tissues other than liver may be an important disease phenotype signature. For instance, apoA-II has been shown to be over-expressed in the serum of individuals with prostate cancer . Under normal conditions the expression of this gene is low in all tissues except liver and spleen. "
[Show abstract][Hide abstract] ABSTRACT: The human liver plays a vital role in meeting the body's metabolic needs and maintaining homeostasis. To address the molecular mechanisms of liver function, we integrated multiple gene expression datasets from microarray, MPSS, SAGE and EST platforms to generate a transcriptome atlas of the normal human liver. Our results show that 17396 genes are expressed in the human liver. 238 genes were identified as liver enrichment genes, involved in the functions of immune response and metabolic processes, from the MPSS and EST datasets. A comparative analysis of liver transcriptomes was performed in humans, mice and rats with microarray datasets shows that the expression profile of homologous genes remains significantly different between mouse/rat and human, suggesting a functional variance and regulation bias of genes expressed in the livers. The integrated liver transcriptome data should provide a valuable resource for the in-depth understanding of human liver biology and liver disease.
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