We propose to test the hypothesis whether the superior antitumor activity exhibited by the experimental drug 10-deazaaminopterin (10-DA) compared to methotrexate (MTX) in several responsive tumors is due to the differences in its ability to undergo metabolism to the poly-Gamma-glutamates. Therefore, a comparative study of the metabolism of 10-DA and MTX will be undertaken to evaluate the relationship between poly-Gamma-glutamation and antitumor activity. These studies will include the biosynthesis, turnover and chemical characterization of these metabolites in mice. A comparative study of the metabolism of both drugs to their poly-Gamma-glutamates will also be undertaken in mice inoculated with the ascitic form of L-1210 leukemia, and the relative accumulation and persistence of these metabolites in the tumor versus the normal drug limiting proliferative tissues will be examined. Our long range objective is to use the information thus obtained to design analogs of 10-DA and MTX which will have altered abilities of poly-Gamma-glutamation; changes which might contribute to the development of more effective anticancer drugs. To aid in these studies 14C-labeled 10-DA and both labeled and unlabeled authentic poly-Gamma-glutamates of 10-DA will be synthetized. As an alternative to the solid phase and classifical solution phase syntheses of the poly-Gamma-glutamyl derivatives, we propose the """"""""solution phase synthesis"""""""" for the preparation of these metabolites which we believe will eiminate the undesirable features of both the existing methods.
