Syntheses and cellular investigations of di-aspartate and aspartate-lysine chlorin e(6) conjugates

Org Biomol Chem. 2016 Jan 21;14(3):1049-64. doi: 10.1039/c5ob02241j. Epub 2015 Dec 3.

Abstract

Chlorin e6 is a tricarboxylic acid degradation product of chlorophyll a. Four chlorin e6 bis(amino acid) conjugates were regioselectively synthesized bearing two aspartate conjugates in the 13(1),17(3)- and 15(2),17(3)-positions, or at the 13(1),15(2)via an ethylene diamine linker. One additional conjugate bearing two different amino acids, lysine at 13(1)via an ethylene diamine linker and an aspartate at 15(2)via a β-alanine linker was also synthesized. The cytotoxicity and uptake of four di(amino acid) chlorin e6 conjugates were investigated in human HEp2 cells, and compared with chlorin e6. The most cytotoxic and most taken up conjugates were the zwitterionic 13(1),15(2)-disubstituted conjugates 28 and 33; these also localized in multiple organelles. In contrast, the anionic 13(1),17(3)- and 15(2),17(3)-di-aspartyl chlorin e6 conjugates 12 and 13 showed low dark cytoxicity and lower phototoxicity compared with chlorin e6.

Publication types

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

MeSH terms

  • Aspartic Acid / chemical synthesis
  • Aspartic Acid / chemistry
  • Aspartic Acid / pharmacology*
  • Cell Survival / drug effects
  • Darkness
  • Hep G2 Cells
  • Humans
  • Light
  • Molecular Conformation
  • Photochemotherapy
  • Photosensitizing Agents / chemical synthesis
  • Photosensitizing Agents / chemistry
  • Photosensitizing Agents / pharmacology*
  • Polylysine / analogs & derivatives*
  • Polylysine / chemical synthesis
  • Polylysine / chemistry
  • Polylysine / pharmacology
  • Stereoisomerism
  • Time Factors
  • Tumor Cells, Cultured

Substances

  • Photosensitizing Agents
  • polylysine-chlorin(E6) conjugate
  • Polylysine
  • Aspartic Acid