Abstract (eng)
The malignant melanoma is one of the most common and aggressive cancers in the world with rising incidence. Genetic factors and environmental influences play an important role in its formation. Elevated IL-6 plasma levels can be detected in inflammatory processes and different cancers and correlate with bad prognosis of melanoma. Elevated IL-6 plasma levels could also be detected in metastatic cell lines in vitro. IL-6 is an important cytokine, which has an influence on different signaling pathways through the IL-6 Receptor and the signal transducing Glycoprotein GP130. Preliminary studies have proven, that the Cholesterol lowering drug Simvastatin reduces the Glycosylation of GP130 in melanoma cells, in a stage dependent manner. The question was, if reduction of glycosylation of Gp130 leads to a changed signal transduction in melanoma cells.
In five melanoma cell lines from different stages it could be observed that treatment with tunicamycin significantly reduced the glycosylation status of Gp130, which simvastatin has already increasingly shown in the metastatic cells. Tunicamycin prevents the activation of Stat3 altogether, whereas simvastatin mainly does this in the metastatic cells. The kinetic of inactivation of Stat3, is unanimously with the reduction of glycosylation in Gp130 and with tunicamycin it simultaneously leads to activation of ERK1/2, NFkB and a beginning of apoptosis, which could be detected through degradation of the marker of apoptosis PARP. Using simvastatin treatment, these effects could be mainly observed in the metastatic cells.
In summary one can see, that the reduction of glycosylation of Gp130 influences the endogenous activation of downstream signaling pathways and creates a proapoptotic situation in this way. The stage dependent effects of simvastatin reveal, that a pharmacological and thus a therapeutic regulation of these signaling pathways is possible.