Development of a double-stranded siRNA labelling method by using 99m Tc and single photon emission computed tomography imaging

• Published in: Journal of drug targeting Vol. 25; no. 2; pp. 172 - 178
• Main Authors: Kano, Daisuke, Nakagami, Yoshihiro, Kurihara, Hiroaki, Hosokawa, Shota, Zenda, Sadamoto, Kusumoto, Masahiko, Fujii, Hirofumi, Kaneta, Tomohiro, Saito, Shinichiro, Uesawa, Yoshihiro, Kagaya, Hajime
• Format: Journal Article
• Language: English
• Published: England 07.02.2017
• Subjects: Animals; Gamma Cameras; Gene Expression Regulation; Gene Transfer Techniques; HEK293 Cells; Humans; Lac Operon; Mice; Molecular Imaging; Radionuclide Imaging; RNA, Double-Stranded; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Small Interfering; Technetium - chemistry; Technetium - pharmacology; Tomography, Emission-Computed, Single-Photon; β-galactosidase; in vivo imaging; vectors; systemic delivery; nanotechnology; gene therapy; genomics; lacZ
• ISSN: 1061-186X; 1029-2330
• DOI: 10.1080/1061186X.2016.1223675

In vivo biodistribution of small interfering RNAs (siRNAs) is important to develop them for medical use. Therefore, novel single photon emitter-labelled siRNA was prepared by using diethylenetriamine-N,N,N',N″,N″-pentaacetic acid (DTPA) and poly(A) polymerase, and subsequently, real-time analysis of siRNA trafficking was performed by using single photon emission computed tomography (SPECT). This study aimed at assessing the use of Tc-radiolabelled siRNA targeting lacZ to detect lacZ expression in vivo. siRNA targeting lacZ was radiolabelled with Tc by using the bifunctional chelator DTPA, and the labelling efficiency and specific activity were determined. The probe stability in RNaseA was assessed. SPECT imaging was performed in mice overexpressing the lacZ gene in the liver. Radiolabelled siRNA remained highly stable in RNaseA solution at 37 °C. In SPECT imaging, significant Tc accumulation in the liver was observed in mice overexpressing the lacZ gene. Tc-labelled lacZ siRNA shows β-galactosidase-specific accumulation and appears promising for the visualisation of lacZ expression in vivo. Our labelled siRNA should be deliverable to specific regions overexpressing the target gene.