Description
Amphiregulin (AR) is a member of the EGF family of cytokines which is comprised of at least ten proteins including EGF, TGF-α, HB-EGF, and the various heregulins. All of these cytokines are synthesized as transmembrane precursors and are characterized by the presence of one or several EGF structural units in their extracellular domain. The soluble forms of these cytokines are released by proteolytic cleavage. Amphiregulin was originally isolated from the conditioned media of a PMA-treated MCF-7 human breast carcinoma cell line. The Amphiregulin mRNA expression can be detected in numerous carcinoma cell lines and the epithelial cells of various human tissues including colon, stomach, breast, ovary, kidney, etc. AR is also a growth inhibitor for various tumor cell lines. In certain colon carcinoma cell lines, AR has been shown to be an autocrine growth factor. Amphiregulin can bind to the EGF receptor. It has been suggested that in certain cell types, AR bioactivity may be mediated through the EGF receptor