Tumor-specific protein human galectin-1 interacts with anticancer agents.

Abstract

The present work shows a novel binding activity of the tumor specific lectin--recombinant human galectin-1 (hGal-1)--to three porphyrin compounds: (1) Zn-porphyrin (ZnTPPS); (2) Mn-porphyrin and (3) Au-porphyrin. These compounds are widely applied in the photodynamic therapy of cancer (PDT). Our data indicate that hGal-1, similar to some plant lectins, a bacterial lectin from Pseudomonas aeruginosa and an animal lectin from Helix pomatia, possesses dual functions binding to both carbohydrate and non-carbohydrate ligands. The interaction of ZnTPPS with hGal-1 was studied by the specific fluorescence emission of the porphyrin. The protein binding properties to Mn/Au-porphyrins and adenine were measured by intrinsic protein fluorescence quenching. The values determined for the apparent dissociation constants (K(D)) of 0.6-1.5 microM are similar to the K(D) for complexes of concanavalin A and porphyrin, and are indicative of the high affinity of hGal-1 for these porphyrins. In addition, the analysis of the hyperbolic binding curves obtained suggests the presence of one hGal-1 binding site for porphyrins or adenine. Additionally, we found that hGal-1 interacts with the fluorescent probe 2-(p-toluidinyl)naphthalene sulfonic acid (TNS), that was used to identify the hydrophobic regions within hGal-1. Homodimeric hGal-1 has more than one class of binding site for TNS as revealed by the sigmoidal shape of the fluorescence titration curve. hGal-1 can be characterized as a porphyrin-binding protein based on its interactions with the Zn/Mn- and Au-porphyrins, and this indicates that hGal-1 may have potential as a delivery molecule to target systems (e.g., tumor cells) with possible application in photodynamic therapy.

• Authors: Sabato D'Auria, Lidia Petrova, Constance John, George Russev, Antonio Varriale, Vanya Bogoeva
• Journal: Molecular bioSystems (Mol Biosyst) Vol. 5 Issue 11 Pg. 1331-6 (Nov 2009) ISSN: 1742-2051 [Electronic] England
• PMID: 19823749 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anticarcinogenic Agents
• Galectin 1
• Metalloporphyrins
• Recombinant Proteins

Topics

• Anticarcinogenic Agents (chemistry, metabolism)
• Galectin 1 (chemistry, metabolism)
• Humans
• Metalloporphyrins (chemistry, metabolism)
• Molecular Structure
• Photochemotherapy (methods)
• Recombinant Proteins (chemistry, metabolism)