Proton-mediated liberation of aldophosphamide from a nontoxic prodrug: a strategy for tumor-selective activation of cytocidal drugs.
Based on the findings that the pH in malignant tumors can be preferentially decreased by stimulation of their aerobic glycolysis, acid-sensible prodrugs, which are nearly nontoxic at physiological pH, were synthesized. At lower pH, however, these compounds are cleaved with liberation of a cytotoxic species. The prototypic drug compound 2-hexenopyranoside of aldophosphamide was prepared, which releases aldophosphamide by acid-catalyzed hydrolysis. Exposure of cultured M1R rat mammary carcinoma cells to this agent at pH 7.4 only resulted in slight toxicity. However, when drug treatment was performed at pH 6.2, the mean pH in malignant tumors of hyperglycemic hosts, the colony-forming fraction of M1R cells decreased to 0.05 and 0.0001 of controls treated at pH 7.4 after exposure for 24 h and 48 h, respectively. The synthesis of the 2-hexenopyranoside of aldophosphamide is described in detail.
Tietze
L F
LF
Institut für Organische Chemie der Georg-August-Universität, Göttingen, Federal Republic of Germany.
Neumann
M
M
Möllers
T
T
Fischer
R
R
Glüsenkamp
K H
KH
Rajewsky
M F
MF
Jähde
E
E
D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism*; D001711:Biotransformation; D002470:Cell Survival / Q000187:drug effects; D006019:Glycolysis; D006863:Hydrogen-Ion Concentration; D010752:Phosphoramide Mustards / Q000378:metabolism*; D011355:Prodrugs / Q000378:metabolism*; D051381:Rats; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000970:Antineoplastic Agents; D010752:Phosphoramide Mustards; D011355:Prodrugs; C006446:aldophosphamide