Systemic administration of 3-bromopyruvate reveals its interaction with serum proteins in a rat model

BMC Res Notes. 2013 Jul 17:6:277. doi: 10.1186/1756-0500-6-277.

Abstract

Background: 3-bromopyruvate (3-BrPA) is a glycolytic inhibitor that affects cancer cells by targeting energy metabolism. Preclinical reports have established that a 1.75 mM dose of 3-BrPA is effective and sufficient to inhibit tumor growth when administered under a loco-regional approach (intraarterial and intratumoral). This loco-regional therapeutic dose was found to be nontoxic when given systemically as well. Yet, the mechanism underlying this lack of toxicity of 1.75 mM 3-BrPA during systemic delivery is unknown. Here, we investigated the mechanism associated with the lack of organ toxicity when 1.75 mM 3-BrPA was administered systemically using radiolabeled (14C)-3-BrPA in Sprague-Dawley rats.

Findings: Data obtained from tissue-autoradiography of rats infused with 14C-3-BrPA showed strong 14C-signal in tissue sections of various organs except the brain corroborating that 3-BrPA does not cross the blood-brain barrier. Significantly, Hematoxylin & Eosin staining and apoptosis assay of tissue sections positive for 14C-signal showed no signs of toxicity or apoptosis. Convincingly, the 14C-signal observed in tissue-autoradiography emanates from 3-BrPA that is non-reactive or non-toxic, hence we further investigated whether the lack of toxicity is due to its interaction or alkylation with serum components. Analysis of serum proteins by 1D and 2D-gel electrophoretic autoradiography showed that 14C-BrPA selectively binds to peptides of molecular mass ~50-60 kDa. Mass spectrometry data suggested that 14C-BrPA could interact with alpha1-antitrypsin and a peptide of albuminoid-family.

Conclusion: Our data indicate that selective interaction of 3-BrPA with serum proteins could contribute to the apparent lack of tissue-toxicity at the indicated close when the drug is given systematically in Sprague-Dawley rats.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Proteins / chemistry*
  • Electrophoresis, Gel, Two-Dimensional
  • Electrophoresis, Polyacrylamide Gel
  • Pyruvates / administration & dosage*
  • Pyruvates / chemistry
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Blood Proteins
  • Pyruvates
  • bromopyruvate