In Vivo Evaluation of Sgc8-c Aptamer as a Molecular Imaging Probe for Colon Cancer in a Mouse Xenograft Model
Ana Paula Arévalo1, Romina Castelli2, Manuel Ibarra3
1Laboratory Animals Biotechnology Unit, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay.
Abstract:
Recent biotechnological applications in the field of clinical oncology led to the identification of new biomarkers as molecular targets of cancer, and to broad developments in the field of personalized medicine. Aptamers are oligonucleotides (ssDNA or RNA) that are selected to specifically recognize a molecular target with high affinity and specificity. Based on this, new horizons for their use as molecular imaging probes are being explored. The objective of this work was to evaluate the Sgc8-c aptamer conjugated with Alexa Fluor 647 fluorophore as an imaging probe in a colon tumor xenograft mouse model, with potential application in molecular imaging. In this study, the LS174T cell line was used to induce colorectal adenocarcinoma in nude mice. After confirmation of PTK7 overexpression by immunohistochemistry, in vivo studies were performed. Pharmacokinetic, in vivo and ex vivo biodistribution imaging, and a competition assay were evaluated by fluorescence imaging. In vivo visualization of the probe in the tumors was assessed two hours after aptamer probe administration, exhibiting excellent tumor-to-background ratios in biodistribution studies and high specificity in the competition test. Our results demonstrated the functionality of Scg8-c as an imaging probe for colon cancer, with potential clinical applications.
Insights
This study shows that the Sgc8-c aptamer, labeled with Alexa Fluor 647, effectively visualizes colon cancer in mice. This aptamer probe demonstrates high specificity and tumor-to-background ratios for potential clinical molecular imaging applications.
Area of Science:
- Biotechnology
- Oncology
- Molecular Imaging
Background:
- Biotechnology advances have identified new cancer biomarkers and personalized medicine.
- Aptamers are oligonucleotides with high affinity and specificity for molecular targets.
- Their potential as molecular imaging probes is under exploration.
Purpose of the Study:
- To evaluate the Sgc8-c aptamer conjugated with Alexa Fluor 647 as an imaging probe.
- To assess its utility in a colon tumor xenograft mouse model for molecular imaging.
Main Methods:
- LS174T cell line used to induce colorectal adenocarcinoma in nude mice.
- Confirmed PTK7 overexpression via immunohistochemistry.
- Evaluated pharmacokinetic, biodistribution (in vivo and ex vivo), and specificity using fluorescence imaging and a competition assay.
Main Results:
- In vivo visualization of the Sgc8-c aptamer probe in tumors was achieved two hours post-administration.
- Demonstrated excellent tumor-to-background ratios in biodistribution studies.
- Showcased high specificity in competition assays, confirming aptamer-target interaction.
Conclusions:
- The Sgc8-c aptamer functions effectively as an imaging probe for colon cancer.
- Results suggest potential clinical applications in molecular imaging for colorectal adenocarcinoma.
