Cryptophane-folate biosensor for (129)xe NMR

Area of Science:

• Bioconjugation Chemistry
• Molecular Imaging
• Cancer Biology

Background:

• Membrane-bound folate receptors are overexpressed in various human cancers, making them attractive targets for cancer therapy.
• Developing targeted delivery systems is crucial for enhancing drug efficacy and reducing side effects in cancer treatment.

Purpose of the Study:

• To develop and characterize a novel folate-conjugated cryptophane biosensor for targeted delivery to cancer cells via folate receptors.
• To evaluate the biosensor's cellular uptake, targeting specificity, and toxicity in cancer and normal cell lines.

Main Methods:

• Synthesis of folate-conjugated cryptophane incorporating a Cy3 fluorophore and solubilizing peptide through a 20-step nonlinear process.
• Hyperpolarized (129)Xe NMR to confirm xenon binding.
• Confocal laser scanning microscopy and flow cytometry for cellular internalization studies.
• Competitive blocking assays to confirm folate receptor-mediated endocytosis.
• MTT assay to assess cytotoxicity.

Main Results:

• Successful synthesis of the folate-conjugated cryptophane biosensor.
• Confirmation of xenon binding to the biosensor using (129)Xe NMR.
• Demonstration of folate receptor-mediated endocytosis and targeted cellular internalization.
• 10-fold higher uptake in KB cancer cells (overexpressing folate receptors) compared to HT-1080 cells (normal folate receptor expression).
• The biosensor exhibited no toxicity in tested cell lines at relevant concentrations.

Conclusions:

• The developed folate-conjugated cryptophane biosensor effectively targets cancer cells overexpressing folate receptors.
• The biosensor demonstrates specific cellular uptake and is non-toxic, indicating its potential as a targeted imaging or therapeutic agent for cancer.