Horm Metab Res 1999; 31(2/03): 80-89
DOI: 10.1055/s-2007-978703
© Georg Thieme Verlag Stuttgart · New York

Insulin and IGF-I Receptors Signaling in Protection from Apoptosis

M. Prisco, G. Romano, F. Peruzzi, B. Valentinis, R. Baserga
  • Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
Further Information

Publication History

1998

1998

Publication Date:
19 April 2007 (online)

R-cells are mouse embryo fibroblasts with a targeted disruption of the insulin-like growth factor I receptor (IGF-IR) genes. Because R-cells do not express the IGF-IR, they are ideal for studying the biological effects of the insulin receptor (IR), independently from any contribution by the IGE-IR. By stably transfecting R-cells with constructs expressing the IR, we show here the IR can protect cells from apoptosis induced by anoilds or by okadaic acid. The IR, however, is not as efficient as the IGF-IR in protecting mouse embryo fibroblasts from apoptosis, even when IRS-1, one of its major substrates, is over-expressed. In addition, the protection by the IGF-IR is resistant to inhibitors of phosphatidylinositol 3-kinase (PI 3-ki), while the anti-apoptotic effect of the IR is sensitive. These experiments suggest that the IGF-IR uses an alternative anti-apoptotic pathway, not shared with the IR, which is PI3-ki-independent.