Authors: Vladimir N. Pak.
Oncofetal alpha-fetoprotein (AFP) activates in developing as well as in growing cancer cells. It delivers polyunsaturated fatty acids through specific cell receptors. AFP-binding receptors are also discovered on myeloidderived suppressor cells which suppress the immune response to the embryo and to the tumor. After AFP receptormediated endocytosis these cells release AFP for the next run for nutrients. The AFP natural shuttle delivery manner can be used for cancer treatments. Oncoshuttle is an exogenous AFP able to bind and deliver toxins instead of nutrients to cancer and myeloid-derived suppressor cells in a repeated way. Toxins for shuttling should have a higher than albumin or other blood proteins binding affinity to AFP. AFP wins the competition for the ligand over albumin due to its unique hydrophobic pocket. Injectable AFP-toxin non-covalent complexes, as well as oral porcine AFP-toxin ones, have demonstrated anticancer activity. The possible role of neonatal Fc receptor in transcytosis of oral porcine AFP-toxin complexes to gastrointestinal tract lymph nodes is discussed.
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