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Published on: July 17, 2012
SYL3C Aptamer-DNA Tetrahedra Conjugates Enable Near-Infrared Fluorescent Imaging of Colorectal Cancer
Zhidie Huang1, Pinghui Li1, Yiwen Li1
1Inner Mongolia Medical University, Hohhot, People's Republic of China.
Purpose:
SYL3C is an optimized DNA aptamer with high selectivity and affinity for the epithelial cell adhesion molecule (EpCAM), an overexpressed tumor antigen in colorectal cancer (CRC). While its cellular affinity has been validated, in vivo studies are lacking.
Methods:
This study modifies SYL3C with the fluorescent motif Cy7 to evaluate its metabolism and diagnostic potential in EpCAM-positive HT-29 xenograft mice using near-infrared fluorescence (NIRF). We also employ DNA Tetrahedra (DTN) to load the Cy7-DTN-SYL3C probe and assess whether this strategy improves circulation and tumor uptake of SYL3C.
Results:
Cy7-SYL3C is primarily metabolized by the kidneys and enables targeted imaging of HT-29 tumors, outperforming untargeted Cy7-DTN. The DTN coupling strategy prolongs SYL3C metabolism and enhances tumor probe uptake about twice higher than Cy7-SYL3C over 24 hours.
Conclusion:
This study presents preliminary evidence for the SYL3C aptamer's potential in vivo imaging of EpCAM-positive CRC. The DTN conjugation strategy may extend the aptamer's metabolic stability and improve tumor uptake, expanding its applications in CRC diagnosis and treatment.
Insights
This study shows that a modified DNA aptamer, SYL3C, can be used for in vivo imaging of colorectal cancer (CRC). DNA tetrahedra improve its stability and tumor targeting for better diagnosis.
Area of Science:
- Biomedical Engineering
- Molecular Imaging
- Cancer Diagnostics
Background:
- SYL3C is a DNA aptamer targeting EpCAM, a tumor antigen in colorectal cancer (CRC).
- Previous studies validated SYL3C's cellular affinity, but in vivo data were missing.
Purpose of the Study:
- To evaluate the in vivo metabolism and diagnostic potential of SYL3C in EpCAM-positive colorectal cancer models.
- To assess if DNA tetrahedra (DTN) conjugation enhances SYL3C's circulation time and tumor uptake.
Main Methods:
- SYL3C was modified with a Cy7 fluorescent dye for near-infrared fluorescence (NIRF) imaging.
- The Cy7-SYL3C probe was evaluated in HT-29 xenograft mice.
- A DNA tetrahedra (DTN) strategy was used to load the Cy7-SYL3C probe (Cy7-DTN-SYL3C).
Main Results:
- Cy7-SYL3C was primarily cleared by the kidneys and successfully imaged HT-29 tumors.
- The DTN conjugation strategy significantly prolonged SYL3C metabolism.
- Tumor probe uptake was approximately doubled with the DTN strategy compared to Cy7-SYL3C alone over 24 hours.
Conclusions:
- The study provides preliminary evidence for SYL3C aptamer's in vivo imaging capability in EpCAM-positive CRC.
- DTN conjugation enhances SYL3C's metabolic stability and tumor accumulation, suggesting potential for CRC diagnosis and therapy.
