A facile and improved synthesis of 17α-{2-(E)-[125I]-iodovinyl}-19-nortestosterone, a no-carrier-added ligand for progesterone receptor analyses

Article abstract of DOI:10.1002/jlcr.2580340104

Strategies for human breast cancer therapy using ¹²⁵I-labeled steroid hormones are clinically attractive in light of the estrogen dependence of and progestogen receptor involvement in many cancers and the favorable microdosimetry resulting from ¹²⁵I decay. We have synthesized the no-carrier-added progesterone receptor ligand 17α-{2-(E)-[¹²⁵I]-iodovinyl}-19-nortestosterone (E-¹²⁵IVNNT) by a simple and high yielding method, and determined its uptake and specific progesterone receptor binding in vitro using T47D human breast carcinoma cells. The ligand was prepared by [¹²⁵I]-iododestannylation of 17α-[2-(E)-tri-n-butylstannylvinyl]-19-nortestosterone (E-TBSVNNT) by using the rare iodinating agent [¹²⁵I]-sodium iodide/ferric sulfate in mixed dichloromethane-water solvent. Cell binding assays demonstrated that E-¹²⁵IVNNT binding to T47D breast carcinoma was specific and saturable with an affinity for the progesterone receptor 10-fold greater than that of ³H-R5020.