| Abstract | Ewing sarcoma/primitive neuroectodermal tumors (EWS/PNET) are characterized by specific chromosomal translocations most often generating a chimeric EWS/FLI-1 gene. Depending on the number of juxtaposed exons assembled, several fusion types have been described with different incidences and prognoses. To assess the impact of each fusion type on the specific phenotypic, tumorigenic, and metastatic features of EWS/PNET, we developed an amenable system using a murine mesenchymal multipotent C3H10T1/2 cell line. Upon transduction of EWS/FLI-1, cells acquired dramatic morphological changes in vitro, including a smaller size and "neurite-like" membrane elongations. Chimeric fusion proteins conferred oncogenic properties in vitro, including anchorage-independent growth and an increased rate of proliferation. Furthermore, EWS/FLI-1 expression blocked mineralization, with concomitant repression of osteoblastic genes, and induced a dramatic repression of the adipocytic differentiation program. Moreover, EWS/FLI-1 promoted an aberrant neural phenotype by the de novo expression of specific neural genes. The intramuscular injection of transduced cells led to tumor development and the induction of overt osteolytic lesions. Analogously, to what was observed in human tumors, type 2 EWS/FLI-1 cells formed primary tumors in immunodeficient mice with a higher incidence and a lower latency than cells bearing types 1 and 3 fusions. By contrast, cells expressing types 2 and 3 fusions showed specific metastatic activity with a higher number of macroscopic metastases in soft tissues and osteolytic lesions in the limbs as compared to type-1-expressing cells. Therefore, the structure of each oncoprotein strongly influenced its tumorigenicity and metastagenicity. Thus, this model provides a basis for understanding the genetic determinants involved in Ewing tumor development and metastatic activity and represents a cellular system to analyze other oncoproteins involved in human sarcomagenesis. |
| Authors | Iranzu González, Silvestre Vicent, Enrique de Alava, Fernando Lecanda
(Affiliation: Division of Oncology, Adhesion and Metastasis Laboratory, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, 31080, Navarra, Spain.)
|
| Journal | Journal of molecular medicine (Berlin, Germany)
(J Mol Med)
Vol. 85
Issue 9
Pg. 1015-29
(Sep 2007)
ISSN: 0946-2716 Germany |
| PMID | 17453169
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
| Chemical References |
- EWS-FLI1 fusion protein
- Oncogene Proteins, Fusion
- Proto-Oncogene Protein c-fli-1
|
| Topics |
- Animals
- Blotting, Western
- Cell Line
- Cell Line, Tumor
- Cell Proliferation
- Cell Transformation, Neoplastic
(genetics, metabolism)
- Female
- Flow Cytometry
- Fluorescent Antibody Technique
- Humans
- Mice
- Mice, Inbred C3H
- Mice, Nude
- Microscopy, Electron, Scanning
- Neoplasm Metastasis
- Oncogene Proteins, Fusion
(genetics, metabolism)
- Proto-Oncogene Protein c-fli-1
(genetics, metabolism)
- Reverse Transcriptase Polymerase Chain Reaction
- Sarcoma, Ewing's
(genetics, pathology, radiography)
- Sarcoma, Experimental
(genetics, pathology, radiography)
- Transplantation, Heterologous
|
