Heterogeneous Nuclear Ribonucleoproteins Involved in the Functioning of Telomeres in Malignant Cells.

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are structurally and functionally distinct proteins containing specific domains and motifs that enable the proteins to bind certain nucleotide sequences, particularly those found in human telomeres. In human malignant cells (HMCs), hnRNP-A1-the most studied hnRNP-is an abundant multifunctional protein that interacts with telomeric DNA and affects telomerase function. In addition, it is believed that other hnRNPs in HMCs may also be involved in the maintenance of telomere length. Accordingly, these proteins are considered possible participants in the processes associated with HMC immortalization. In our review, we discuss the results of studies on different hnRNPs that may be crucial to solving molecular oncological problems and relevant to further investigations of these proteins in HMCs.

Study of Splicing Factor, Proline- and Glutamine-rich by Proteomic Techniques in Human Malignant and Nonmalignant Cell Lines.

Splicing factor, proline- and glutamine-rich protein (SFPQ), was identified in eight human cultivated cell lines by proteomic approaches. The cell proteins have been separated by means of two-dimensional gel electrophoresis in two modifications and identified by matrix-assisted laser desorption ionization mass spectrometry with further tandem mass spectrometry. The analysis of proteins from three human sarcomas cell lines (RD, U-2 OS and SK-UT-1B), three human renal adenocarcinomas cell lines (A-498, 769-P and OKP-GS), and two prostate adenocarcinomas cell lines (DU-145 and PC-3) revealed several electrophoretic isoforms of SFPQ protein. Differences between theoretical and experimental molecular masses and isoelectric points of SFPQ protein have been observed. Detailed investigation of SFPQ peptides by tandem mass spectrometry has detected new phosphorylation state of threonine residue in 168 position of SFPQ isoform in rhabdomyosarcoma cell line. Furthermore, SFPQ has not been identified during proteomic study of several nonmalignant cell lines, including cultured human mesenchymal stromal cells and myoblasts. However, SFPQ has been found in all malignant cell lines in high quantity. In particular, its fractions are abundant in sarcomas cell lines as opposed to nonmalignant mesenchymal cells. It is assumed that high quantity of SFPQ in sarcomas cell lines may affect tumorigenesis.

Enzyme immunoassay and proteomic characterization of troponin I as a marker of mammalian muscle compounds in raw meat and some meat products.

The skeletal muscle protein troponin I (TnI) has been characterized as a potential thermally stable and species-specific biomarker of mammalian muscle tissues in raw meat and meat products. This study proposed a technique for the quantification of TnI comprising protein extraction and sandwich enzyme-linked immunosorbent assay (ELISA). The technique is characterized by a TnI detection limit of 4.8 ng/ml with quantifiable concentrations ranging from 8.7 to 52 ng/ml. The method was shown to be suitable for detection of TnI in mammalian (beef, pork, lamb, and horse) meat but not in poultry (chicken, turkey, and duck) meat. In particular, the TnI content in beef was 0.40 3 ± 0.058 mg/g of wet tissue. The TnI estimations obtained for the pork and beef samples using ELISA were comparable to the proteomic analysis results. Thus, the quantitative study of TnI can be a convenient way to assess the mammalian muscle tissue content of various meat products.