@article{WendlingerWohlfarthKreftetal.2022, author = {Wendlinger, Simone and Wohlfarth, Jonas and Kreft, Sophia and Siedel, Claudia and Kilian, Teresa and Dischinger, Ulrich and Heppt, Markus V. and Wistuba-Hamprecht, Kilian and Meier, Friedegund and Goebeler, Matthias and Schadendorf, Dirk and Gesierich, Anja and Kosnopfel, Corinna and Schilling, Bastian}, title = {Blood eosinophils are associated with efficacy of targeted therapy in patients with advanced melanoma}, series = {Cancers}, volume = {14}, journal = {Cancers}, number = {9}, issn = {2072-6694}, doi = {10.3390/cancers14092294}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-275137}, year = {2022}, abstract = {Background: Eosinophils appear to contribute to the efficacy of immunotherapy and their frequency was suggested as a predictive biomarker. Whether this observation could be transferred to patients treated with targeted therapy remains unknown. Methods: Blood and serum samples of healthy controls and 216 patients with advanced melanoma were prospectively and retrospectively collected. Freshly isolated eosinophils were phenotypically characterized by flow cytometry and co-cultured in vitro with melanoma cells to assess cytotoxicity. Soluble serum markers and peripheral blood counts were used for correlative studies. Results: Eosinophil-mediated cytotoxicity towards melanoma cells, as well as phenotypic characteristics, were similar when comparing healthy donors and patients. However, high relative pre-treatment eosinophil counts were significantly associated with response to MAPKi (p = 0.013). Eosinophil-mediated cytotoxicity towards melanoma cells is dose-dependent and requires proximity of eosinophils and their target in vitro. Treatment with targeted therapy in the presence of eosinophils results in an additive tumoricidal effect. Additionally, melanoma cells affected eosinophil phenotype upon co-culture. Conclusion: High pre-treatment eosinophil counts in advanced melanoma patients were associated with a significantly improved response to MAPKi. Functionally, eosinophils show potent cytotoxicity towards melanoma cells, which can be reinforced by MAPKi. Further studies are needed to unravel the molecular mechanisms of our observations.}, language = {en} } @article{HoeslFroehlichPoschetal.2021, author = {Hoesl, Christine and Fr{\"o}hlich, Thomas and Posch, Christian and Kneitz, Hermann and Goebeler, Matthias and Schneider, Marlon R. and Dahlhoff, Maik}, title = {The transmembrane protein LRIG1 triggers melanocytic tumor development following chemically induced skin carcinogenesis}, series = {Molecular Oncology}, volume = {15}, journal = {Molecular Oncology}, number = {8}, doi = {10.1002/1878-0261.12945}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-238925}, pages = {2140 -- 2155}, year = {2021}, abstract = {The incidence of melanoma and nonmelanoma skin cancer has increased tremendously in recent years. Although novel treatment options have significantly improved patient outcomes, the prognosis for most patients with an advanced disease remains dismal. It is, thus, imperative to understand the molecular mechanisms involved in skin carcinogenesis in order to develop new targeted treatment strategies. Receptor tyrosine kinases (RTK) like the ERBB receptor family, including EGFR/ERBB1, ERBB2/NEU, ERBB3, and ERBB4, are important regulators of skin homeostasis and their dysregulation often results in cancer, which makes them attractive therapeutic targets. Members of the leucine-rich repeats and immunoglobulin-like domains protein family (LRIG1-3) are ERBB regulators and thus potential therapeutic targets to manipulate ERBB receptors. Here, we analyzed the function of LRIG1 during chemically induced skin carcinogenesis in transgenic mice expressing LRIG1 in the skin under the control of the keratin 5 promoter (LRIG1-TG mice). We observed a significant induction of melanocytic tumor formation in LRIG1-TG mice and no difference in papilloma incidence between LRIG1-TG and control mice. Our findings also revealed that LRIG1 affects ERBB signaling via decreased phosphorylation of EGFR and increased activation of the oncoprotein ERBB2 during skin carcinogenesis. The epidermal proliferation rate was significantly decreased during epidermal tumorigenesis under LRIG1 overexpression, and the apoptosis marker cleaved caspase 3 was significantly activated in the epidermis of transgenic LRIG1 mice. Additionally, we detected LRIG1 expression in human cutaneous squamous cell carcinoma and melanoma samples. Therefore, we depleted LRIG1 in human melanoma cells (A375) by CRISPR/Cas9 technology and found that this caused EGFR and ERBB3 downregulation in A375 LRIG1 knockout cells 6 h following stimulation with EGF. In conclusion, our study demonstrated that LRIG1-TG mice develop melanocytic skin tumors during chemical skin carcinogenesis and a deletion of LRIG1 in human melanoma cells reduces EGFR and ERBB3 expression after EGF stimulation.}, language = {en} }