Insulin-like Growth Factor（IGF） Family

Insulin-like growth factor (IGF) is a group of growth hormones that play a key role in regulating the signaling processes critical to cell proliferation, differentiation, and survival. These growth factors are expressed in various tissues and cell types, with autocrine, paracrine and endocrine functions. There are two types of IGFs, type I(IGF-I) and type II (IGF-II), act by binding to their specific membrane receptors: IGF-I R and IGF-II R.

As with IGF, IGF receptors are also potential targets for targeted therapies. IGF-I R is a heterotetrameric transmembrane protein with two disulfide-linked alpha subunits and two transmembrane beta subunits. Activation of this pathway has been linked to cancer initiation and growth, with many types of tumor cells overexpressing IGF-IR to promote resistance to radiotherapy, chemotherapy and targeted therapies. To overcome this resistance, IGF / IGF-IR targeted therapies have become a viable cancer treatment strategy. Teprotumumab, a representative drug targeting IGF-IR, was approved by the US Food and Drug Administration (FDA) in 2020 for the treatment of thyroid-associated ophthalmopathy (TAO). Initial studies suggest that combined targeting of IGF-IR and STAT3 may inhibit tumor metastasis and overcome resistance to STAT3-mediated anti-IGF-IR therapy, maximizing the efficacy of cancer treatment.