Folate receptor targeted imaging using poly (ethylene glycol)-folate: in vitro and in vivo studies.
The aim of this study was to ascertain the folate receptor (FR) targetability by an in vitro study and to acquire FR-targeted images in vivo models by using synthetic folate conjugates. PEG-folate was synthesized and labeled with (99m)Tc and fluorescein isothiocynate (FITC). Cell uptake studies were carried out in KB cells (FR-positive) and A549 cells (FR-negative) using FITC- and the (99m)Tc-labeled conjugates. The radiolabeled conjugate was intravenously injected to KB tumor xenografted mice. After it was injected, gamma images were recorded at 30 min, 1, 2, 3 and 4 hr. Cell uptake studies showed a difference between the KB cells and the A549 cells by flow cytometry analysis and gamma counting. On in vivo images, the tumor-to-normal muscle ratio was greater than 4. It ascertained that the PEG-folate conjugate specifically binds to the FR expressed on tumor cells in vitro. Moreover, it was possible to acquire the FR-targeted gamma images using PEG-folate conjugates in tumor models.
Kim
Se-Lim
SL
Department of Nuclear Medicine, Chonbuk National University Hospital, 634-18 Geumam-2 dong, Duckjin-gu, Jeonju, Korea.
Jeong
Hwan-Jeong
HJ
Kim
Eun-Mi
EM
Lee
Chang-Moon
CM
Kwon
Tae-Hyoung
TH
Sohn
Myung-Hee
MH
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D005260:Female; D016650:Fluorescein-5-isothiocyanate / Q000494:pharmacology; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D009368:Neoplasm Transplantation; D011092:Polyethylene Glycols / Q000737:chemistry*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013667:Technetium / Q000737:chemistry*; D013997:Time Factors
D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D011956:Receptors, Cell Surface; D011092:Polyethylene Glycols; D013667:Technetium; D005492:Folic Acid; D016650:Fluorescein-5-isothiocyanate