Related Experiment Video
Updated: May 7, 2026
Pretargeted Radioimmunotherapy Based on the Inverse Electron Demand Diels-Alder Reaction
Published on: January 29, 2019
Double-targeting using a TrkC ligand conjugated to dipyrrometheneboron difluoride (BODIPY) based photodynamic therapy
Anyanee Kamkaew1, Kevin Burgess
1Department of Chemistry, Texas A & M University , Box 30012, College Station, Texas 77842, United States.
Abstract:
A molecule 1 (IY-IY-PDT) was designed to contain a fragment (IY-IY) that targets the TrkC receptor and a photosensitizer that acts as an agent for photodynamic therapy (PDT). Molecule 1 had submicromolar photocytotoxicities to cells that were engineered to stably express TrkC (NIH3T3-TrkC) or that naturally express high levels of TrkC (SY5Y neuroblastoma lines). Control experiments showed that 1 is not cytotoxic in the dark and has significantly less photocytotoxicity toward cells that do not express TrkC (NIH3T3-WT). Other controls featuring a similar agent 2 (YI-YI-PDT), which is identical and isomeric with 1 except that the targeting region is scrambled (a YI-YI motif, see text), showed that 1 is considerably more photocytotoxic than 2 on TrkC(+) cells. Imaging live TrkC(+) cells after treatment with a fluorescent agent 1 (IY-IY-PDT) proved that 1 permeates into TrkC(+) cells and is localized in the lysosomes. This observation indirectly indicates that agent 1 enters the cells via the TrkC receptor. Consistent with this, the dose-dependent PDT effects of 1 can be competitively reduced by the natural TrkC ligand, neurotrophin NT3.
Insights
Molecule 1, a novel photodynamic therapy agent, selectively targets TrkC receptors. It demonstrates potent photocytotoxicity against TrkC-expressing cells, indicating targeted cancer therapy potential.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Therapy
Background:
- The TrkC receptor plays a role in neuronal development and has been implicated in certain cancers.
- Photodynamic therapy (PDT) is a treatment modality that uses light to activate a photosensitizer, generating cytotoxic reactive oxygen species.
- Targeted drug delivery can enhance the efficacy and reduce the side effects of cancer therapies.
Purpose of the Study:
- To design and synthesize a novel molecule (Molecule 1) combining a TrkC receptor-targeting moiety with a photosensitizer for photodynamic therapy.
- To evaluate the photocytotoxicity of Molecule 1 against cells expressing TrkC.
- To investigate the mechanism of cellular uptake and localization of Molecule 1.
Main Methods:
- Synthesis of Molecule 1 (IY-IY-PDT) and a control agent (YI-YI-PDT).
- Photocytotoxicity assays on TrkC-expressing cells (NIH3T3-TrkC, SY5Y) and control cells (NIH3T3-WT).
- Cellular imaging studies using fluorescently labeled Molecule 1 and competition assays with neurotrophin NT3.
Main Results:
- Molecule 1 exhibited submicromolar photocytotoxicity against TrkC-expressing cells, with minimal dark toxicity.
- Photocytotoxicity was significantly lower in TrkC-negative cells.
- A scrambled analog (YI-YI-PDT) showed reduced photocytotoxicity, confirming the specificity of the IY-IY targeting motif.
- Molecule 1 localized to lysosomes in TrkC-expressing cells, suggesting TrkC-mediated uptake.
- Cellular uptake and photodynamic effects were competitively inhibited by NT3, further supporting TrkC receptor engagement.
Conclusions:
- Molecule 1 is a potent and selective TrkC receptor-targeting photosensitizer for photodynamic therapy.
- The IY-IY motif effectively directs the photosensitizer to TrkC-expressing cells.
- TrkC receptor-mediated endocytosis and lysosomal localization are key to Molecule 1's cellular activity.
- This targeted approach holds promise for developing novel TrkC-targeted cancer therapies.
More Related Videos
11:04An In-House-Built and Light-Emitting-Diode-Based Photodynamic Therapy Device for Enhancing Verteporfin Cytotoxicity in a 2D Cell Culture Model
Published on: January 13, 2023
09:45Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers
Published on: October 28, 2015
