Human IGF-1R Reporter Assay Kit

Target Background

Insulin-like Growth Factor-1 Receptor (IGF-1R) is a Type 1 IGF receptor belonging to the receptor tyrosine kinase (RTK) family. IGF-1R activity is mediated by both IGF-1 and insulin. Upon ligand binding, the receptor is capable of activating several signal transduction pathways, including PI 3-Kinase and Ras-MAPK to regulate proliferation, migration, and inhibition of apoptosis. Although signaling pathways mediated by both IGF-I and insulin are quite similar, the biological and physiological responses are quite different between them. Activation of IGF-I/IGF-1R regulates cellular growth and proliferation, whereas insulin mediates more dramatic glycolytic responses. Several in-vivo and in-vitro studies have indicated that correlation and relationships of IGF-I/IGF-1R signaling in cancer development as well as cancer cell lines. Now clinical approaches to inhibit IGF-I/IGF-1R signaling in cancer development have been investigated using monoclonal antibodies and small molecules.

. IGF-1R is a tetrameric transmembrane protein. The extracellular α2 subunits form the ligand-binding domain, and the disulfide linked β subunits form the transmembrane domains and the intracellular tyrosine kinase domains. Following IGF-I binding, the tyrosine kinase domains are activated and initiate intracellular signaling cascades that include RAS-MAPK pathways. For example, activation of the RAS-MAPK pathway leads to activation of ERK1/2 and subsequent phosphorylation and activation of the transcription factor Elk-17. It is IGF-1R signal transduction via the RAS-MAPK-ERK1/2 cascade that is exploited by the reporter cells provided in this kit.

INDIGO’s IGF-1R Reporter Cells express a hybrid Elk-1transprion factor in which the native Elk-1 DNA-binding domain (DBD) has been replaced with the yeast Gal4 DBD sequence. The luciferase reporter gene is functionally linked to an upstream Gal4 Upstream Activation Sequence (UAS). When activated, Elk-1 binds to the UAS elements to initiate the formation of a complete transcription complex that drives Luc gene expression. Quantifying changes in luciferase activity in the treated reporter cells relative to the untreated cells provides a sensitive, dose-dependent surrogate measure of drug-induced changes in IGF-1R activity.

Therefore, the principal application of this assay is in the screening of test materials to quantify any functional interactions, either activating or inhibitory, that they may exert against IGF-1R or the coupled RAS-MAPK pathway.