Factors that influence the penetration of methotrexate through solid tissue

Int J Cancer. 2001 Jan 1;91(1):120-5. doi: 10.1002/1097-0215(20010101)91:1<120::aid-ijc1021>3.0.co;2-y.

Abstract

Limited penetration of anticancer drugs through tumour tissue is an important factor that may limit therapeutic effects against solid tumours. Here we report studies of the penetration of radiolabelled methotrexate through multicellular layers (MCL) of murine EMT-6 and human MCF-7 cells grown on semiporous teflon membranes. The penetration of methotrexate was only about 25% of that through the teflon membrane alone after 6 hr. This was true for all methotrexate concentrations examined from 10 microM to 3 mM. The presence of folic acid at concentrations above 0.1 mM and of acidic conditions decreased the uptake of methotrexate into single cells and enhanced tissue penetration. Hypoxic conditions and the presence of folinic acid (leucovorin) had no effect on penetration or uptake of methotrexate. Our data provide evidence that tissue penetration of methotrexate is through the extracellular space, that its distribution in solid tissue may be limited and that it may be possible to improve its tissue penetration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antimetabolites, Antineoplastic / pharmacokinetics*
  • Breast Neoplasms / drug therapy
  • Cell Culture Techniques
  • Cell Survival / drug effects
  • Dose-Response Relationship, Drug
  • Female
  • Folic Acid / pharmacology
  • Humans
  • Hydrogen-Ion Concentration
  • Hypoxia
  • Leucovorin / pharmacology
  • Mammary Neoplasms, Animal / drug therapy
  • Methotrexate / pharmacokinetics*
  • Mice
  • Polytetrafluoroethylene
  • Time Factors
  • Tumor Cells, Cultured

Substances

  • Antimetabolites, Antineoplastic
  • Polytetrafluoroethylene
  • Folic Acid
  • Leucovorin
  • Methotrexate