Protein Profiling of the Supratentorial Primitive Neuroectodermal Tumor (PNET) Cell Line PFSK-1

Background: Supratentorial primitive neuroectodermal tumors (PNETs) are rare embryonal cerebral hemispheric tumors proposed to arise from primitive neuroepithelial cells. The permanent cell line PFSK-1 is widely used in studies of this tumor entity and it was the aim of this study to generate a proteome map to serve as a basis for further studies to search for tumor-related proteins.

Materials and methods: The PNET-related cell line PSFK-1 was cultivated and proteins from cell lysates were subject to two-dimensional gel electrophoresis with in gel-digestion of protein spots and subsequent MALDI-MS identification.

Results: Among the 157 proteins identified by this method we observed structural, metabolic, chaperone, antioxidant, transcriptional / translational proteases as well as miscellaneous proteins. Hypothetical proteins similar to pyrroline-5-carboxylate reductase isoform, similar to 3-hydroxyisobutyryl-Coenzyme A hydrolase, thioredoxin domain containing protein 5 precursor, potential helicase with zinc-finger domain, an unnamed protein product and proteins P1.11659_4 and Pro1512 were detected.

Conclusion: No neuronal, glial or other specific markers were found; the presence of vimentin may point to a mesenchymal rather than an epithelial origin; expression of developmentally expressed potential helicase P42694 indicates immaturity and FUSE binding protein 1 provides a link to myc, a major protooncogene, and to differentiation per se. We provide an analytical tool unambiguously identifying structures of several protein classes and show the existence of several hypothetical proteins, that had so far been predicted from nucleic acid sequences only and never detected in mammalian cell lines or tissues at the protein level.