Progress of Studies of Anti-Tumor Therapies Based on Targeting Insulin-like Growth Factor System
Insulin-like growth factor(IGF)system is composed of ligands,receptors and binding proteins.The main ligands are IGF-1,IGF-2 and insulin,functioning by binding to specific receptors,including IGF type 1 receptor(IGF-1R),IGF type 2 receptor(IGF-2R),insulin receptor(IR)and the hybrid receptor of IGF-1R and IR.The IGF system also includes six high-affinity IGF binding proteins(IGFBP-1 to 6).IGF system plays a key role not only in regulation of important physiological processes(such as cell growth,differentiation and metabolism,etc.),but also in tumor development and progression through varying expression levels of components.Recent studies have shown that targeting individual components of the IGF system or its related signaling pathways is helpful in blocking the development and progression of tumor and has beneficial effects on subsequent anti-tumor therapy.This article reviews the role of the individual components of IGF system and the related signaling pathways in tumor and the current research situation of anti-tumor agents targeting the components of IGF system,and analyzes the problems encountered in anti-tumor therapy targeting the IGF system,in order to provide ideas for the study on anti-tumor agents targeting IGF system.