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DOI: 10.1055/s-0028-1096347
Experimental modulation of the canonical Wnt-signalling pathway in primary cell cultures of craniopharyngiomas
Craniopharyngiomas (CP) are benign epithelial tumors of the sellar region, to be histologically and clinically distinguished as papillary and adamantionomatous subtypes. The latter is characterised by activating beta-catenin mutations as well as aberrant nuclear beta-catenin accumulation in a subset of tumor cells. Functional analyses about the impact of altered Wnt-signalling pathway in the pathogenesis of craniopharyngiomas remains, however, limited since tumor cell-lines and animal models are not yet available. Here, we established primary human CP cell cultures from surgically resected tumor specimens. Using immunohistochemistry, cultured tumor cells show a distinct expression of cytokeratin (KL1) as well as beta-catenin. Real time RT-PCR analysis confirmed target gene activation of the Wnt-signalling pathway i.e. Axin2 in adamantionomatous tumor cell cultures (n=5) compared to papillary controls (n=1). Further activation of the Wnt-signalling pathway induced by LiCl increased nuclear beta-catenin accumulation in a dose dependent manner (nuclear immunoblotting). Interestingly, tumor cells treated 24 hours with 40mM LiCl showed a decreased proliferation in MTT- and BrdU assays as well as an increased expression of p21, BMP4 and Axin2 in contrast to untreated controls. In conclusion, our cell culture model allows the in vitro modulation of the Wnt-signalling pathway in human CP and opens new avenues to unravel the functional role of this pathway in the pathogenesis of CPs.
Support: RB/AH (Elan-Fond, Univ. Hospital Erlangen)