Expression von zellulären Antigenen eines Hypopharynxkarzinoms unter verschiedenen Kulturbedingungen

Zusammenfassung

Hintergrund: Tumorzell- und -gewebekulturen (2-dimensionale Monolayer [ML], 3-dimensionale multizelluläre Tumorsphäroide [MTS] und Substrat-Kulturen [SK] auf Gelita) sollten biologische Eigenschaften ihrer Ausgangstumoren repräsentieren. Kulturbedingungen u.a. können aber die Expression zellulärer Antigene ändern. Methode: Ein Plattenepithelkarzinom des Hypopharynx wurde immunhistochemisch hinsichtlich der Ausprägung der Zytokeratine (CK) 1, 7, 10, 14, 18 und 19, Vimentin, Neurofilamente (NF) kD200 und kD68, Gangliosid CD2, Onkogen-Produkten (P53 mutiert und wild) und membranassoziierten Antigenen (HLA-ABC und -DR, ECFR) an Gefrierschnitten (CS) und an In-vitro-Kulturen (ML, MTS, SK) untersucht. Ergebnisse: Semiquantitativ waren deutliche Unterschiede in der Expression von CK1,14 und 19, CD2 und P53 mutiert nachweisbar. MTS exprimierten die Marker mindestens genauso stark wie die CS und stärker als die ML. Schlußfolgerungen: Die Antigen-Expression der MTS kam derjenigen in der Tumorbiopsie am nächsten. Die schwache Expression in den SK kann durch lockere Zell-Zellkontakte bedingt sein.

Summary

Background: The need to improve therapy regims, determine prognosis, and study biological properties of tumors extracorporally led to development of different experimental systems. In order to approach the in vivo situation, specific properties of the tumors of origin should be retained by the cells in culture over relatively long periods. However, culture conditions may change expression of cellular antigens. Methods: Cryosections of a hypopharyngeal carcinoma were compared in this respect with different cultivation systems (2-dimensional monolayers [ML], 3-dimensional multicellular tumor spheroids [MTS] and substrate cultures on Gelita®) in regard to expression of cytokeratins (CK) 1, 7, 10, 14, 18 and 19, vimentin, neurofilament (NF) kD200 and 68, ganglioside GD2, oncogene products (P53 mutant and wild), and membrane-associated antigens (HLA-ABC and -DR, epidermal growth factor receptor EGFR). Results: Semiquantitative immunohistochemical methods revealed differences in expression of CK1,14 and 19, GD2, and P53 mutant between these systems. Conclusion: Pronounced expression of markers in MTS compared to original biopsy and monolayer emphasizes the importance of cell-cell contact and 3-dimensionality or metabolic stress. However, weak marker expression within substrate cultures may reflect loose cell-cell contact observed. In these experiments, the antigenic configuration of MTS resembled the one of the original tumor more than the other culture systems: monolayer and growth on substrate. As vimentin and NF are not expressed by healthy epithelial cells of adults, occurrence of intratumoral vimentin and NF could point to derepression of early differentiation antigens.

Schlüsselwörter

Plattenepithelkarzinome - In-vitro-Kulturen - Monolayer-Kulturen - Multizelluläre Tumorsphäroide - Organkulturen - Intermediärfilamente - p53-Produkte - Membranassoziierte Antigene - Immunhistochemie

Key words

Squamous cell carcinomas - In vitro culture - Monolayer cultures - Multicellular tumor spheroids - Organ cultures - Intermediate filaments - P53 products - Membrane associated antigens - Immunohistochemistry