The feasibility of enzyme targeted activation for amino acid/dipeptide monoester prodrugs of floxuridine; cathepsin D as a potential targeted enzyme

Molecules. 2012 Mar 26;17(4):3672-89. doi: 10.3390/molecules17043672.

Abstract

The improvement of therapeutic efficacy for cancer agents has been a big challenge which includes the increase of tumor selectivity and the reduction of adverse effects at non-tumor sites. In order to achieve those goals, prodrug approaches have been extensively investigated. In this report, the potential activation enzymes for 5'-amino acid/dipeptide monoester floxuridine prodrugs in pancreatic cancer cells were selected and the feasibility of enzyme specific activation of prodrugs was evaluated. All prodrugs exhibited the range of 3.0-105.7 min of half life in Capan-2 cell homogenate with the presence and the absence of selective enzyme inhibitors. 5'-O-L-Phenylalanyl-L-tyrosyl-floxuridine exhibited longer half life only with the presence of pepstatin A. Human cathepsin B and D selectively hydrolized 5'-O-L-phenylalanyl-L-tyrosylfloxuridine and 5'-O-L-phenylalanyl-L-glycylfloxuridine compared to the other tested prodrugs. The wide range of growth inhibitory effect by floxuridine prodrugs in Capan-2 cells was observed due to the different affinities of prodrug promoieties to enzymes. In conclusion, it is feasible to design prodrugs which are activated by specific enzymes. Cathepsin D might be a good candidate as a target enzyme for prodrug activation and 5'-O-L-phenylalanyl-L-tyrosylfloxuridine may be the best candidate among the tested floxuridine prodrugs.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acids / metabolism
  • Antimetabolites, Antineoplastic / metabolism*
  • Antimetabolites, Antineoplastic / pharmacology
  • Cathepsin B / metabolism
  • Cathepsin D / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Dipeptides / metabolism
  • Drug Stability
  • Enzyme Activation / drug effects
  • Floxuridine / metabolism*
  • Floxuridine / pharmacology
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Pancreatic Neoplasms / drug therapy
  • Pancreatic Neoplasms / enzymology
  • Pancreatic Neoplasms / genetics
  • Prodrugs / metabolism*
  • Prodrugs / pharmacology

Substances

  • Amino Acids
  • Antimetabolites, Antineoplastic
  • Dipeptides
  • Prodrugs
  • Floxuridine
  • Cathepsin B
  • Cathepsin D