Improvement of meta-tetra(hydroxyphenyl)chlorin-like photosensitizer selectivity with folate-based targeted delivery. synthesis and in vivo delivery studies

J Med Chem. 2008 Jul 10;51(13):3867-77. doi: 10.1021/jm800125a. Epub 2008 Jun 14.

Abstract

The cell membrane folate receptor (FR) is a molecular target for tumor-selective drug delivery, including delivery of photosensitizers for anticancer photodynamic therapy (PDT). Tumor selectivity of meta-tetra(hydroxyphenyl)chlorin ( m-THPC), a photosensitizer used in PDT clinical trials, demonstrates a low tumor-to-normal epithelial uptake ratio. We report on the synthesis and on the photophysical properties of a m-THPC-like photosensitizer 1 conjugated to folic acid (compound 8). A comparative study of the accumulation of photosensitizers 1 and 8 is described. Nude mice were xenografted with FR-alpha-positive KB or HT-29 cells lacking FR-alpha as a negative control. Using optical fiber fluorimetry, we demonstrated that conjugate 8 exhibited enhanced accumulation in KB tumors compared to 1 4 h after injection. No significant difference between KB and HT-29 tumors was observed in case of compound 1. Tumor-to-normal tissue ratio exhibited a very interesting selectivity for conjugate 8 (5:1) in KB tumors 4 h postinjection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell Line, Tumor
  • Drug Delivery Systems*
  • Female
  • Folate Receptors, GPI-Anchored
  • Folic Acid / metabolism*
  • Gene Expression Regulation / drug effects
  • Humans
  • Mesoporphyrins / administration & dosage*
  • Mesoporphyrins / chemical synthesis*
  • Mesoporphyrins / chemistry
  • Mice
  • Mice, Nude
  • Molecular Structure
  • Neoplasms / metabolism
  • Neoplasms / pathology
  • Photochemistry
  • Photosensitizing Agents / administration & dosage*
  • Photosensitizing Agents / chemical synthesis*
  • Photosensitizing Agents / chemistry
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / metabolism
  • Spectrophotometry
  • Xenograft Model Antitumor Assays

Substances

  • Carrier Proteins
  • Folate Receptors, GPI-Anchored
  • Mesoporphyrins
  • Photosensitizing Agents
  • Receptors, Cell Surface
  • Folic Acid
  • temoporfin