Improved synthesis and biological evaluation of Tc-99m radiolabeled AMO for miRNA imaging in tumor xenografts.
MicroRNAs (miRNAs) have been considered as important biomarkers for malignant tumors. In this study, we introduced an improved (99m)Tc labeling method for noninvasive visualization of overexpressed miRNAs in tumor-bearing mice. Anti-miRNA-21 oligonucleotide (AMO) with partial 2'-O-methyl and phosphorothioate modification was designed and chemically synthesized. After conjugated with NHS-MAG3, AMO was labeled with (99m)Tc. Optimization was made to shorten reaction time and to improve labeling efficiency. Labeling efficiency was 97%, and specific activity was 2.78 MBq/ng. During 12 h, (99m)Tc-AMO showed no significant degradation by gel electrophoresis. Its radiochemical purity was stable, between 95.8% and 99.1%. Further, (99m)Tc-AMO decreased the level of miR-21 and increased the expression of PTEN protein at cellular level, shown by qRT-PCR and Western blot. Fluorescent protein labeled AMO displayed specific distribution and good stability in tumor cells. After the administration in tumor-bearing mice, (99m)Tc-AMO showed more radioactive uptake in the miR-21 over-expressed tumors than scramble control. Biodistribution results further proved the significant difference of tumor uptake between (99m)Tc-AMO and (99m)Tc-control. Therefore, this study presents an improved method with shorten time to prepare a (99m)Tc radiolabeled AMO. In addition, it supports the role of (99m)Tc-AMO for noninvasive visualization of miR-21 in malignant tumors.
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Lei
L
Kang
Department of Oncology, PLA General Hospital, Beijing, 100853, China.
Zhongyi
Z
Fan
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Hongwei
H
Sun
Department of Colorectal Surgery, Second Artillery General Hospital, Beijing, 100088, China.
Yingying
Y
Feng
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Chao
C
Ma
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Ping
P
Yan
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Chunli
C
Zhang
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Huan
H
Ma
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Pan
P
Hao
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Xueqi
X
Chen
Laboratory of Computer-aided Drug Design and Discovery, Beijing Institute of Pharmacology and Toxicology, Beijing, 100850, China.
Zhibing
Z
Zheng
Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Beijing, 100850, China.
Xiaojie
X
Xu
Department of Nuclear Medicine, Peking University First Hospital, Beijing, 100034, China.
Rongfu
R
Wang
D000818:Animals; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000737:chemistry*; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging*; D020320:Oligoribonucleotides, Antisense / Q000737:chemistry*; D019275:Radiopharmaceuticals / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D017263:Technetium Tc 99m Mertiatide / Q000737:chemistry*; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon
D035683:MicroRNAs; D020320:Oligoribonucleotides, Antisense; D019275:Radiopharmaceuticals; D017263:Technetium Tc 99m Mertiatide
99mTc; AMO; SPECT; microRNA; molecular imaging; radiolabel