About FOLR / Folate Receptor:
Folate receptors bind folate and reduced folic acid derivatives and mediate tetrahydrofolate delivery to the cell's interior. It is then transformed from monoglutamate forms to polyglutamate forms, such as 5-methyltetrahydrofolate, since only monoglutamate forms can cross cell membranes. Polyglutamate forms are biologically active enzymatic cofactors necessary for a variety of folate-dependent processes, including folate-dependent one-carbon metabolism. A GPI anchor holds these proteins to the membrane. This family also includes a riboflavin-binding protein that is necessary for the transport of riboflavin to the developing oocyte in chicken.
Folate receptor is abundantly expressed in a wide range of cancers, including carcinoma and brain tumors. The targeting of the folate receptor has been shown to be very promising in mediating drug absorption, and several studies have shown that there is a substantial difference in uptake by folate-targeted liposomes between cells with overexpression of folate receptors and those with no expression of folate receptors. Conversely, the expression in healthy tissues is limited to the placenta, lung, kidneys, and choroid plexus. Indeed, after the seminal publication by Leamon and Low in 1991, successful targeting of hFR has become a Trojan horse in the race toward more efficient cancer and inflammatory disease diagnosis and treatment.However, the clinical evaluation of folate-modified nanomedicines loaded with anticancer drugs has not yet been applied to hospitals6 and has primarily focused on the targeting of metallic nanoparticles for cancer diagnosis. Endocyte, Inc. currently has many drugs in the pipeline for the treatment of cancer, inflammation, and polycystic kidney disease that are in various stages of advanced preclinical or early clinical study.