PO-17 - Identification of IgG bound to plasminogen in oncologic diseases.

INTRODUCTION: The binding of plasminogen (Pg) to cell receptors and extracellular ligands facilitates its activation to plasmin, which stimulates the extracellular matrix degradation, neoangiogenesis and tumor invasion. Plasmin can also degrade IgG thereby exposing C-terminal lysine residues. Previously, we have found IgG specifically bounded to Pg in the plasma of patients with malignant tumors. AIM: To identify IgG degraded by plasmin in the plasma of cancer patients. MATERIALS AND METHODS: Methods of ELISA were used for comparative research of levels of IgG bound to Pg in plasma of patients with the prostate cancer (PC, n=25) and lung cancer (LC, n=17). Plasma of healthy donors (n=29) was used as control. All patients signed informed consent for participation in this study. Affinity chromatography on Pg-sepharose was used for the quantification of IgG. Carboxypeptidase was used for remove of C-terminal lysine residues of the IgG. The program ATTESTAT was used for nonparametric analysis. RESULTS: The frequency of occurence of elevated levels of IgG to Pg in plasma was detected in 68% of patients with PC, 59% of patients with LC and only 12% of healthy women and 10% of healthy men. The quantification of antibodies in plasma samples showed that the quantity of IgG to Pg in patients with PC was 27% from the total amount of IgG and in healthy men - 9%. Treatment of diluted plasma samples with carboxypeptidase B abolished the elevated levels of IgG to Pg, as well as the specific activity of the purified IgG to Pg-sepharose. CONCLUSIONS: C-terminal lysine residues which are formed as a result of degradation of native IgG with plasmin can bind to lysine binding sites on the kringle domains of Pg. Increased levels of these degraded IgG can be marker at cancer.

Autoantibodies to plasminogen and their role in tumor diseases.

Plasma level of IgG autoantibodies to plasminogen was measured by ELISA in patients with benign prostatic hyperplasia (n=25), prostatic cancer (n=17), lung cancer (n=15), and healthy volunteers (n=44). High levels of IgG to plasminogen were found in 2 (12%) of 17 healthy women, in 1 (3.6%) of 27 specimens in a healthy man, in 17 (68%) of 25 specimens in prostatic cancer, in 10 (59%) of 17 specimens in lung cancer, and in 5 (30%) of 15 specimens in benign prostatic hyperplasia. Comparison of plasma levels of anti-plasminogen IgG by affinity chromatography showed 3-fold higher levels in patients with prostatic cancer vs. healthy men.

Two-dimensional electrophoretic proteome study of serum thermostable fraction from patients with various tumor conditions.

One of the problems of plasma proteomics is a presence of large major components. In this work, we use the thermostable fraction as a way to deplete these major proteins. The thermostable fraction of serum samples from patients with ovarian, uterus, and breast cancers and benign ovarian tumor was analyzed using two-dimensional electrophoresis combined with MALDI-TOF(-TOF)-mass spectrometry. Of them, alpha-1-acid glycoprotein and clusterin are expressly down-regulated in breast cancer, whereas transthyretin is decreased specifically in ovarian cancer. Apolipoprotein A-I forms have decreased spot volumes, while haptoglobin alpha1, in contrast, is elevated in several tumors. These data are partly consistent with previous art studies on cancer proteomics, which involve mass-spectrometry-based serum profiling techniques. Serum thermostable fraction may be recommended as a good tool for medium and small protein proteome investigation, in particular, by 2D-electrophoresis.

[Early proteomics in ovarian cancer: myth or reality?]. / Ranniaia proteomika raka iaichnikov. Mif ili real'nost'?

Literature data summarizing new approaches and importance of early ovary cancer diagnostics have been reviewed. Alpha-feta-protein (AFP) and SA125 were the most reliable markers for determination of early ovary cancer stages. Nevertheless, these markers don't reflect the disease stage, malignance and they don't possess sufficient specificity. New methodical approaches have recently been introduced. They include combination of 2-D electrophoresis with mass-spectrometry. These methods allow to inventory and identify almost all proteins of various tissues. Using these methods for scanning proteins from biopsies of ovary cancer tissues new markers have been discovered.

Comparative analysis of proteome maps of Helicobacter pylori clinical isolates.

The gram-negative bacterium Helicobacter pylori is found in human gastric mucosa. A widely distributed H. pylori infection is associated with chronic gastritis, gastric and duodenal ulcers, and malignant neoplasms. In this study proteome maps of four H. pylori clinical isolates derived from patients of two Russian regions (Moscow/Moscow Region and Novosibirsk) were obtained using 2D-electrophoresis and MALDI-TOF-mass-spectrometry. Variability of some H. pylori proteins and the level of their expression have been evaluated. These four isolates could be easily subdivided into two equal groups characterized by the close proteome profiles and the isolate from Moscow Region and the isolate from Novosibirsk constituted one group. The present study demonstrates the potential of proteome technology, which can be employed together with genome and transcriptome studies for the multiparameter typing of clinical isolates of pathogenic microorganisms.