Expression of an IGF-I receptor dominant negative mutant induces apoptosis, inhibits tumorigenesis and enhances chemosensitivity in Ewing's sarcoma cells.
IGF-IR plays an essential role in the establishment and maintenance of the transformed phenotype of ES cells and interference with the IGF-IR pathways causes reversal of the malignant potential of this neoplasm. In this report, we stably transfected a dominant negative IGF-IR expression plasmid in an ES cell line to determine the effectiveness of this strategy against the in vitro and in vivo growth of ES cells. DXR sensitivity of TC-71 cells expressing dominant negative mutants of IGF-IR was also examined. The mutated IGF-IR that we used carries a mutation in the ATP-binding domain of the intracellular beta subunit, while the extracellular, ligand-binding alpha subunit remains unchanged. Cells carrying the dominant mutant IGF-IR had a marked decrease in proliferation, a significant increase in anoikis-induced apoptosis and a severely reduced ability to form colonies in soft agar. In vivo, when cells carrying dominant negative IGF-IR were injected into nude mice, the tumor formation and metastatic abilities of ES cells were reduced and survival increased. Furthermore, transfected clones showed significantly higher sensitivity to DXR, a major drug in the treatment of ES. These results indicate that the IGF/IGF-IR stimulation of ES cells may be inhibited by expression of mutated IGF-IR on their surfaces and that this strategy may be considered a possible alternative to impair this important target of ES cells, whose therapeutic potential was further confirmed.
Scotlandi
Katia
K
Laboratorio di Ricerca Oncologica, Istituti Ortopedici Rizzoli, Bologna, Italy. katia.scotlandi@ior.it
Avnet
Sofia
S
Benini
Stefania
S
Manara
Maria Cristina
MC
Serra
Massimo
M
Cerisano
Vanessa
V
Perdichizzi
Stefania
S
Lollini
Pier-Luigi
PL
De Giovanni
Carla
C
Landuzzi
Lorena
L
Picci
Piero
P
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004317:Doxorubicin / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D051379:Mice; D008819:Mice, Nude; D009154:Mutation; D009368:Neoplasm Transplantation; D017526:Receptor, IGF Type 1 / Q000235:genetics* / Q000378:metabolism*; D012512:Sarcoma, Ewing / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D015996:Survival Rate; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
D004317:Doxorubicin; D017526:Receptor, IGF Type 1