Design of spindle poisons activated specifically by prostatic acid phosphatase (PAP) and new methods for PAP cytochemistry.

By taking advantage of the structural requirements of the substrates for prostatic acid phosphatase (PAP), which consist of steric hindrance and the presence of basic nitrogen in the molecule, potential cytotoxic agents (spindle poisons) are being designed that will become enzyme activated specifically by PAP. Colchicine has been converted to colchiceinamides of substituted ethanolamines and o-phosphoethanolamines. The rate of hydrolysis of the latter by human prostatic tissue as compared to the rate of hydrolysis by human kidneys (P/K ratio) is given and indicates a significant degree of specificity for PAP. Some preliminary toxicity data in mice are also given. New thiocolchicine derivatives with phosphates on ring B are also being prepared for study and some preliminary toxicity data are given. The observation in biochemical experiments that phosphorylcholine is a very specific substrate for PAP has led us to develop specific cytochemical methods for PAP for both light and electron microscopy. Preliminary observations are given and good evidence is provided that PAP is not a lysosomal enzyme, unlike other acid phosphatases. Furthermore, PAP is to other acid phosphatases what the cholinesterases are to other esterases. Since the acid phosphatase that is able to hydrolyze phosphorylcholine is characteristic of prostatic epithelium, this is the acid phosphatase that is referred to be the designation of PAP. Other acid phosphatases (both lysosomal and nonlysosomal) in prostatic epithelial cells are not demonstrated by this substrate and hence are not included in this designation.