@article{HoubenEbertHesbacheretal., author = {Houben, Roland and Ebert, Marlies and Hesbacher, Sonja and Kervarrec, Thibault and Schrama, David}, title = {Merkel Cell Polyomavirus Large T Antigen is Dispensable in G2 and M-Phase to Promote Proliferation of Merkel Cell Carcinoma Cells}, series = {Viruses}, volume = {12}, journal = {Viruses}, number = {10}, issn = {1999-4915}, doi = {10.3390/v12101162}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218171}, abstract = {Merkel cell carcinoma (MCC) is an aggressive skin cancer frequently caused by the Merkel cell polyomavirus (MCPyV), and proliferation of MCPyV-positive MCC tumor cells depends on the expression of a virus-encoded truncated Large T antigen (LT) oncoprotein. Here, we asked in which phases of the cell cycle LT activity is required for MCC cell proliferation. Hence, we generated fusion-proteins of MCPyV-LT and parts of geminin (GMMN) or chromatin licensing and DNA replication factor1 (CDT1). This allowed us to ectopically express an LT, which is degraded either in the G1 or G2 phase of the cell cycle, respectively, in MCC cells with inducible T antigen knockdown. We demonstrate that LT expressed only in G1 is capable of rescuing LT knockdown-induced growth suppression while LT expressed in S and G2/M phases fails to support proliferation of MCC cells. These results suggest that the crucial function of LT, which has been demonstrated to be inactivation of the cellular Retinoblastoma protein 1 (RB1) is only required to initiate S phase entry.}, language = {en} } @article{KervarrecSamimiGuyetantetal.2019, author = {Kervarrec, Thibault and Samimi, Mahtab and Guy{\´e}tant, Serge and Sarma, Bhavishya and Ch{\´e}ret, J{\´e}r{\´e}my and Blanchard, Emmanuelle and Berthon, Patricia and Schrama, David and Houben, Roland and Touz{\´e}, Antoine}, title = {Histogenesis of Merkel Cell Carcinoma: A Comprehensive Review}, series = {Frontiers in Oncology}, volume = {9}, journal = {Frontiers in Oncology}, doi = {10.3389/fonc.2019.00451}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325733}, year = {2019}, abstract = {Merkel cell carcinoma (MCC) is a primary neuroendocrine carcinoma of the skin. This neoplasia features aggressive behavior, resulting in a 5-year overall survival rate of 40\%. In 2008, Feng et al. identified Merkel cell polyomavirus (MCPyV) integration into the host genome as the main event leading to MCC oncogenesis. However, despite identification of this crucial viral oncogenic trigger, the nature of the cell in which MCC oncogenesis occurs is actually unknown. In fact, several hypotheses have been proposed. Despite the large similarity in phenotype features between MCC tumor cells and physiological Merkel cells (MCs), a specialized subpopulation of the epidermis acting as mechanoreceptor of the skin, several points argue against the hypothesis that MCC derives directly from MCs. Alternatively, MCPyV integration could occur in another cell type and induce acquisition of an MC-like phenotype. Accordingly, an epithelial as well as a fibroblastic or B-cell origin of MCC has been proposed mainly based on phenotype similarities shared by MCC and these potential ancestries. The aim of this present review is to provide a comprehensive review of the current knowledge of the histogenesis of MCC.}, language = {en} }