| Autor: |
Vélez-Reyes GL; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA., Koes N; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA., Ryu JH; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA., Kaufmann G; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA., Berner M; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA., Weg MT; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA., Wolf NK; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA., Rathe SK; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA., Ratner N; College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA.; Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45267, USA., Moriarity BS; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.; Department of Pediatrics, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA., Largaespada DA; Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.; Department of Pediatrics, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA. |
| Abstrakt: |
Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive, genomically complex, have soft tissue sarcomas, and are derived from the Schwann cell lineage. Patients with neurofibromatosis type 1 syndrome (NF1), an autosomal dominant tumor predisposition syndrome, are at a high risk for MPNSTs, which usually develop from pre-existing benign Schwann cell tumors called plexiform neurofibromas. NF1 is characterized by loss-of-function mutations in the NF1 gene, which encode neurofibromin, a Ras GTPase activating protein (GAP) and negative regulator of RasGTP-dependent signaling. In addition to bi-allelic loss of NF1 , other known tumor suppressor genes include TP53 , CDKN2A , SUZ12 , and EED , all of which are often inactivated in the process of MPNST growth. A sleeping beauty (SB) transposon-based genetic screen for high-grade Schwann cell tumors in mice, and comparative genomics, implicated Wnt/β-catenin, PI3K-AKT-mTOR, and other pathways in MPNST development and progression. We endeavored to more systematically test genes and pathways implicated by our SB screen in mice, i.e., in a human immortalized Schwann cell-based model and a human MPNST cell line, using CRISPR/Cas9 technology. We individually induced loss-of-function mutations in 103 tumor suppressor genes (TSG) and oncogene candidates. We assessed anchorage-independent growth, transwell migration, and for a subset of genes, tumor formation in vivo. When tested in a loss-of-function fashion, about 60% of all TSG candidates resulted in the transformation of immortalized human Schwann cells, whereas 30% of oncogene candidates resulted in growth arrest in a MPNST cell line. Individual loss-of-function mutations in the TAOK1 , GDI2 , NF1 , and APC genes resulted in transformation of immortalized human Schwann cells and tumor formation in a xenograft model. Moreover, the loss of all four of these genes resulted in activation of Hippo/Yes Activated Protein (YAP) signaling. By combining SB transposon mutagenesis and CRISPR/Cas9 screening, we established a useful pipeline for the validation of MPNST pathways and genes. Our results suggest that the functional genetic landscape of human MPNST is complex and implicate the Hippo/YAP pathway in the transformation of neurofibromas. It is thus imperative to functionally validate individual cancer genes and pathways using human cell-based models, to determinate their role in different stages of MPNST development, growth, and/or metastasis. |
