RT Journal Article
SR Electronic
T1 Galectin-3 Targeting in Thyroid Orthotopic Tumors Opens New Ways to Characterize Thyroid Cancer
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 770
OP 776
DO 10.2967/jnumed.118.219105
VO 60
IS 6
A1 Francesco De Rose
A1 Miriam Braeuer
A1 Sten Braesch-Andersen
A1 Angela M. Otto
A1 Katja Steiger
A1 Sybille Reder
A1 Sabine Mall
A1 Stephan Nekolla
A1 Markus Schwaiger
A1 Wolfgang A. Weber
A1 Armando Bartolazzi
A1 Calogero D’Alessandria
YR 2019
UL http://jnm.snmjournals.org/content/60/6/770.abstract
AB Preoperative characterization of thyroid nodules is challenging since thyroid scintigraphy fails to distinguish between benign and malignant lesions. Galectin-3 (gal-3) is expressed in well-differentiated and in undifferentiated thyroid cancer types but not in normal thyrocytes and benign thyroid lesions. Herein, we aimed to validate gal-3 targeting as a specific method to detect non–radioiodine-avid thyroid cancer in thyroid orthotopic tumor models. Methods: Papillary (BcPAP) and anaplastic (CAL62 and FRO82-1) thyroid carcinoma cell lines were characterized via Western blot and polymerase chain reaction for gal-3 and sodium-iodide symporter (NIS) expression. An 89Zr-labeled F(ab′)2 antigal-3 was generated and characterized for binding versus 125I on 2- and 3-dimensional cell cultures. The thyroid carcinoma cells were inoculated into the left thyroid lobe of athymic nude mice, and the orthotopic tumor growth was monitored via ultrasound and fluorescence molecular tomography. Head-to-head PET/CT comparison of 124I versus 89Zr-deferoxamine (DFO)-F(ab′)2 antigal-3 was performed, followed by biodistribution studies and immunohistochemical analysis for gal-3 and NIS expression. Results: The thyroid carcinoma cells investigated were invariably gal-3–positive while presenting low or lost NIS expression. 89Zr-DFO-F(ab′)2 antigal-3 tracer showed high affinity to gal-3 (dissociation constant, ∼3.9 nM) and retained immunoreactivity (>75%) on 2-dimensional cell cultures and on tumor spheroids. 125I internalization in FRO82-1, BcPAP, and CAL62 was directly dependent on NIS expression, both in 2-dimensional and tumor spheroids. PET/CT imaging showed 89Zr-DFO-F(ab′)2 antigal-3 signal associated with the orthotopically implanted tumors only; no signal was detected in the tumor-free thyroid lobe. Conversely, PET imaging using 124I showed background accumulation in tumor-infiltrated lobe, a condition simulating the presence of non–radioiodine-avid thyroid cancer nodules, and high accumulation in normal thyroid lobe. Imaging data were confirmed by tracer biodistribution studies and immunohistochemistry. Conclusion: A specific and selective visualization of thyroid tumor by targeting gal-3 was demonstrated in the absence of radioiodine uptake. Translation of this method into the clinical setting promises to improve the management of patients by avoiding the use of unspecific imaging methodologies and reducing unnecessary thyroid surgery.