A new fluorescence/PET probe for targeting intracellular human telomerase reverse transcriptase (hTERT) using Tat peptide-conjugated IgM.
Despite an increasing need for methods to visualize intracellular proteins in vivo, the majority of antibody-based imaging methods available can only detect membrane proteins. The human telomerase reverse transcriptase (hTERT) is an intracellular target of great interest because of its high expression in several types of cancer. In this study, we developed a new probe for hTERT using the Tat peptide. An hTERT antibody (IgG or IgM) was conjugated with the Tat peptide, a fluorescence dye and (64)Cu. HT29 (hTERT+) and U2OS (hTERT-) were used to visualize the intracellular hTERT. The hTERT was detected by RT-PCR and western blot. Fluorescence signals for hTERT were obtained by confocal microscopy, live cell imaging, and analyzed by Tissue-FAXS. In nude mice, tumors were visualized using the fluorescence imaging devices Maestro™ and PETBOX. In RT-PCR and western blot, the expression of hTERT was detected in HT29 cells, but not in U2OS cells. Fluorescence signals were clearly observed in HT29 cells and in U2OS cells after 1 h of treatment, but signals were only detected in HT29 cells after 24 h. Confocal microscopy showed that 9.65% of U2OS and 78.54% of HT29 cells had positive hTERT signals. 3D animation images showed that the probe could target intranuclear hTERT in the nucleus. In mice models, fluorescence and PET imaging showed that hTERT in HT29 tumors could be efficiently visualized. In summary, we developed a new method to visualize intracellular and intranuclear proteins both in vitro and in vivo.
Department of Nuclear Medicine, Seoul National University College of Medicine, South Korea; Biomedical Sciences, Seoul National University College of Medicine, South Korea; Cancer Research Institute, Seoul National University College of Medicine, South Korea; Tumor Microenvironment Global Core Research Center, Seoul National University, South Korea.
Kyung Oh
KO
Jung
Department of Nuclear Medicine, Seoul National University College of Medicine, South Korea; Cancer Research Institute, Seoul National University College of Medicine, South Korea; Tumor Microenvironment Global Core Research Center, Seoul National University, South Korea; Cancer Imaging Center, Seoul National University Hospital, Seoul, South Korea. Electronic address: hwyoun@snu.ac.kr.
Hyewon
H
Youn
Department of Nuclear Medicine, Seoul National University College of Medicine, South Korea; Cancer Research Institute, Seoul National University College of Medicine, South Korea.
Seung Hoo
SH
Kim
Department of Nuclear Medicine, Seoul National University College of Medicine, South Korea; Biomedical Sciences, Seoul National University College of Medicine, South Korea; Cancer Research Institute, Seoul National University College of Medicine, South Korea.
Young-Hwa
YH
Kim
Department of Nuclear Medicine, Seoul National University College of Medicine, South Korea; Cancer Research Institute, Seoul National University College of Medicine, South Korea.
Keon Wook
KW
Kang
Department of Nuclear Medicine, Seoul National University College of Medicine, South Korea; Biomedical Sciences, Seoul National University College of Medicine, South Korea; Cancer Research Institute, Seoul National University College of Medicine, South Korea; Tumor Microenvironment Global Core Research Center, Seoul National University, South Korea. Electronic address: jkchung@snu.ac.kr.
June-Key
JK
Chung
D000818:Animals; D045744:Cell Line, Tumor; D005453:Fluorescence; D006801:Humans; D007075:Immunoglobulin M / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D010455:Peptides / Q000737:chemistry*; D019098:Telomerase / Q000378:metabolism*
D007075:Immunoglobulin M; D010455:Peptides; C509186:TERT protein, human; D019098:Telomerase
(64)Cu; IgM antibody; Intracellular and intranuclear protein; Live cell imaging; Tat peptide; hTERT