Objective To prepare and characterize

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Lu-DOTA-anti-CIITED1-PNA

a

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Lu-labled antisense probe for the antisense peptide nucleic acid（asPNA） of Cbp/p300 interacting transactivator with Glu/Asp rich carboxy-terminal domain 1（CITED1） mRNA and assess its uptake and cytotoxicity in human papillary thyroid cancer K1 cells. Methods The targeting specificity of the peptide nucleic acid was identified by RT-PCR. The antisense probe

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Lu-DOTA-anti-CITED1-PNA was obtained using an indirect labeling method

and the labeling rate and in vitro and in vivo stability of the probe were assessed. The uptake of the antisense probe and its effect on the proliferation of K1 cells in vitro were evaluated. Results RT-PCR showed that the asPNA could significantly reduce the expression of CITED1 in K1 cells. The prepared antisense probe had a radiochemical purity of（94.5±0.12）% with a specific activity of 3.7±0.53 MBq/μg; its radiochemical purity was still above 90% after 48 h. This antisense probe could be specifically taken up by human K1 cells

and compared with

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Lu-labeled DOTA and a nonsense-PNA

the antisense probe

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Lu-DOTA-anti-CITED1-PNA showed a much stronger anti-tumor effect in K1 cells. Conclusion We successfully obtained

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Lu-labeled CITED1 asPNA probe

which can specifically target K1 cells and effectively reduce the cell viability and proliferation in vitro.