PET Imaging of Tenascin-C with a ssDNA Aptamer

Wednesday, September 24, 2014 — Poster Session IV
10:00 a.m. –12:00 p.m.	FAES Academic Center	NIBIB	CANCER-10

* FARE Award Winner

Authors

• O. Jacobson
• X. Yan
• N. Gang
• Y. Ma
• L.P. Szajek
• D.O. Kiesewetter
• X. Chen

Abstract

Background: Tenascin-C (TsC) is an extracellular matrix glycoprotein, expressed by various cancers, and was shown to support tumor growth, metastasis and angiogenesis. Currently there is no method to determine TsC expression by tumor cells in vivo. Positron emission tomography (PET) is a non-invasive nuclear imaging technology that allows measurement of tumor metabolism and biochemistry. In order to address the need for an agent to image TsC, we developed a radioactive PET tracer based on a TsC specific single stranded DNA aptamer (ssDNA AP). Methods: ssDNA AP targeting TsC was radiolabeled with either 18F or 64Cu. The stability of the radiolabeled AP was evaluated in vitro and in vivo. PET studies were performed in mice bearing TsC-positive and -negative tumors. Results: The ssDNA AP was radiolabeled with either 18F or 64Cu with a radiochemical purity >99% and stability studies showed no significant amount of metabolites. PET imaging using 18F or 64Cu labeled AP visualized only TSc positive tumors. The labeled AP rapidly cleared from nonspecific organs to give high tumor contrast. Conclusion: radiolabeled ssDNA AP can be used as a PET tracer to image tumor expression of TsC with a high tumor-to-background ratio and might help provide personalized therapy and monitoring.

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