Browsing by Author "Deeg, M."

The alpha-defensins human neutrophil peptides (HNPs)-1, -2, and -3 have been described as cytotoxic peptides with restricted expression in neutrophils and in some lymphocytes. In this study we report that HNPs-1, -2, and -3 are also expressed in renal cell carcinomas (RCCs). Several RCC lines were found to express mRNA as well as the specific peptides of HNP-1, -2, and -3 demonstrated by reverse transcriptase-polymerase chain reaction, mass spectrometric, and flow cytometric analyses. At physiological concentrations HNPs-1, -2, and -3 stimulated cell proliferation of selected RCC lines in vitro but at high concentrations were cytotoxic for all RCC lines tested. As in RCC lines, alpha-defensins were also detected in vivo in malignant epithelial cells of 31 RCC tissues in addition to their expected presence in neutrophils. In most RCC cases randomly, patchy immunostaining of alpha-defensins on epithelial cells surrounding neutrophils was seen, but in six tumors of higher grade malignancy all tumor cells were diffusely stained. Cellular necrosis observed in RCC tissues in association with extensive patches of HNP-1, -2, and -3, seemed to be related to high concentrations of alpha-defensins. The in vitro and in vivo findings suggest that alpha-defensins are frequent peptide constituents of malignant epithelial cells in RCC with a possible direct influence on tumor proliferation.

The molecular analysis of serum is an important field for the definition of potential diagnostic markers or disease-related protein alterations. Novel proteomic technologies such as the mass spectrometric-based surface-enhanced laser desorption/ionization (SELDI) ProteinChip(R), technique facilitate a rapid and reproducible analysis of such protein mixtures and affords the researcher a new dimension in the search for biomarkers of disease. Here, we have applied this technology to the study of a cohort of serum samples from well-characterized renal cell carcinoma patients for the identification of such proteins by comparison to healthy controls. We detected and characterized haptoglobin 1 a and serum amyloid alpha-1 (SAA-1) as disease related, in addition to an as-yet-unidentified marker of 10.84 kDa. Of particular note is the detection of multiple variants of SAA-1 in multiplex that have not been described in the sera of cancer patients. SAA-1 is detected as full-length protein, des-Arginine and des-Arginine/des-Serine variants at the N terminus by SELDI. In addition, we could also detect a low-abundant variant minus the first five N-terminal amino acids. Such variants may impact the function of the protein. We conclude the technique to be a reproducible, fast and simple mode for the discovery and analysis of marker proteins of disease in serum.