@article{HoubenCelikdemirKervarrecetal.2023, author = {Houben, Roland and Celikdemir, B{\"u}ke and Kervarrec, Thibault and Schrama, David}, title = {Merkel cell polyomavirus: infection, genome, transcripts and its role in development of Merkel cell carcinoma}, series = {Cancers}, volume = {15}, journal = {Cancers}, number = {2}, issn = {2072-6694}, doi = {10.3390/cancers15020444}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-305021}, year = {2023}, abstract = {The best characterized polyomavirus family member, i.e., simian virus 40 (SV40), can cause different tumors in hamsters and can transform murine and human cells in vitro. Hence, the SV40 contamination of millions of polio vaccine doses administered from 1955-1963 raised fears that this may cause increased tumor incidence in the vaccinated population. This is, however, not the case. Indeed, up to now, the only polyomavirus family member known to be the most important cause of a specific human tumor entity is Merkel cell polyomavirus (MCPyV) in Merkel cell carcinoma (MCC). MCC is a highly deadly form of skin cancer for which the cellular origin is still uncertain, and which appears as two clinically very similar but molecularly highly different variants. While approximately 80\% of cases are found to be associated with MCPyV the remaining MCCs carry a high mutational load. Here, we present an overview of the multitude of molecular functions described for the MCPyV encoded oncoproteins and non-coding RNAs, present the available MCC mouse models and discuss the increasing evidence that both, virus-negative and -positive MCC constitute epithelial tumors.}, language = {en} } @article{HoubenAlimovaSarmaetal.2023, author = {Houben, Roland and Alimova, Pamela and Sarma, Bhavishya and Hesbacher, Sonja and Schulte, Carolin and Sarosi, Eva-Maria and Adam, Christian and Kervarrec, Thibault and Schrama, David}, title = {4-[(5-methyl-1H-pyrazol-3-yl)amino]-2H-phenyl-1-phthalazinone inhibits MCPyV T antigen expression in Merkel cell carcinoma independent of Aurora kinase A}, series = {Cancers}, volume = {15}, journal = {Cancers}, number = {9}, issn = {2072-6694}, doi = {10.3390/cancers15092542}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313547}, year = {2023}, abstract = {Merkel cell carcinoma (MCC) is frequently caused by the Merkel cell polyomavirus (MCPyV), and MCPyV-positive tumor cells depend on expression of the virus-encoded T antigens (TA). Here, we identify 4-[(5-methyl-1H-pyrazol-3-yl)amino]-2H-phenyl-1-phthalazinone (PHT) — a reported inhibitor of Aurora kinase A — as a compound inhibiting growth of MCC cells by repressing noncoding control region (NCCR)-controlled TA transcription. Surprisingly, we find that TA repression is not caused by inhibition of Aurora kinase A. However, we demonstrate that β-catenin — a transcription factor repressed by active glycogen synthase kinase 3 (GSK3) — is activated by PHT, suggesting that PHT bears a hitherto unreported inhibitory activity against GSK3, a kinase known to function in promoting TA transcription. Indeed, applying an in vitro kinase assay, we demonstrate that PHT directly targets GSK3. Finally, we demonstrate that PHT exhibits in vivo antitumor activity in an MCC xenograft mouse model, suggesting a potential use in future therapeutic settings for MCC.}, language = {en} }