TY - JOUR
T1 - β-Gal Gene Expression MRI Reporter in Melanoma Tumor Cells. Design, Synthesis, and in Vitro and in Vivo Testing of a Gd(III) Containing Probe Forming a High Relaxivity, Melanin-Like Structure upon β-Gal Enzymatic Activation
AU - Arena, Francesca
AU - Singh, Jebasingh Bhagavath
AU - Gianolio, Eliana
AU - STEFANIA, Rachele
AU - Aime, Silvio
PY - 2011
Y1 - 2011
N2 - The aim of this work is to design and test an MRI probe (Gd-DOTAtyr-gal) able to report on the gene expression of beta-galactosidase (beta-Gal) in melanoma cells. The probe consists of a Gd-DOTA reporter bearing on its surface a tyrosine-galactose-pyranose functionality that, upon the release of the sugar moiety, readily transforms, in the presence of tyrosinase, into melanin oligomeric/polyrneric mixture. The formation of Gd-DOTA-containing melanin oligomers and polymers is accompanied by a marked increase of the water proton relaxation rate. The steps involving the release of the galactose-pyranose group and the formation of the melanin-like structure have been carefully investigated in vitro by relaxometric and UV- vis measurements. Cellular uptake studies of Gd-DOTAtyr-gal by melanoma cells have shown that the probe enters the cells, and it appears not to be confined in endosomal vesicles. Using B16-F10LacZ transfected cells, the fast formation of paramagnetic melanin-Gd(III)-containing species has been assessed by the measurement of increased longitudinal relaxation rates of the cellular pellets suspensions. The in vitro results have been confirmed in in vivo MRI investigations on murine melanoma tumor bearing mice. Upon direct injection of Gd-DOTAtyr-gal, a good contrast is observed after S h post injection in B16-F10LacZ tumors, but not in B16-F10 tumors lacking the beta-Gal enzyme. Gd-DOTAtyr-gal in combination with tyrosinase introduces a novel approach for the detection of beta-Gal expression by MRI in vivo.
AB - The aim of this work is to design and test an MRI probe (Gd-DOTAtyr-gal) able to report on the gene expression of beta-galactosidase (beta-Gal) in melanoma cells. The probe consists of a Gd-DOTA reporter bearing on its surface a tyrosine-galactose-pyranose functionality that, upon the release of the sugar moiety, readily transforms, in the presence of tyrosinase, into melanin oligomeric/polyrneric mixture. The formation of Gd-DOTA-containing melanin oligomers and polymers is accompanied by a marked increase of the water proton relaxation rate. The steps involving the release of the galactose-pyranose group and the formation of the melanin-like structure have been carefully investigated in vitro by relaxometric and UV- vis measurements. Cellular uptake studies of Gd-DOTAtyr-gal by melanoma cells have shown that the probe enters the cells, and it appears not to be confined in endosomal vesicles. Using B16-F10LacZ transfected cells, the fast formation of paramagnetic melanin-Gd(III)-containing species has been assessed by the measurement of increased longitudinal relaxation rates of the cellular pellets suspensions. The in vitro results have been confirmed in in vivo MRI investigations on murine melanoma tumor bearing mice. Upon direct injection of Gd-DOTAtyr-gal, a good contrast is observed after S h post injection in B16-F10LacZ tumors, but not in B16-F10 tumors lacking the beta-Gal enzyme. Gd-DOTAtyr-gal in combination with tyrosinase introduces a novel approach for the detection of beta-Gal expression by MRI in vivo.
UR - https://iris.uniupo.it/handle/11579/185102
U2 - 10.1021/bc200486j
DO - 10.1021/bc200486j
M3 - Article
SN - 1043-1802
VL - 22
SP - 2625
EP - 2635
JO - Bioconjugate Chemistry
JF - Bioconjugate Chemistry
IS - 12
ER -