<p>MR molecular imaging of HCC employing a regulated ferritin gene carried by a modified polycation vector</p>

Abstract

Purpose: Early diagnosis is essential for reducing liver cancer mortality, and molecular diagnosis by magnetic resonance imaging (MRI) is an emerging and promising technology. The chief aim of the present work is to use the ferritin gene, modified by the alpha-fetoprotein (AFP) promoter, carried by a highly safe vector, to produce signal contrast on T2-weighted MR imaging as an endogenous contrast agent, and to provide a highly specific target for subsequent therapy. Methods: Polyethyleneimine-β-cyclodextrin (PEI-β-CD, PC) was synthesized as a novel vector. The optimal nitrogen/phosphorus ratio (N/P) of the PC/plasmid DNA complex was determined by gel retardation, biophysical properties and transmission electron microscopy morphological analysis. The transfection efficiency was observed under a fluorescence microscope and analyzed by flow cytometry. Cellular iron accumulation caused by ferritin overexpression was verified by Prussian blue staining, and the resulting contrast imaging effect was examined by MRI. Results: The modified cationic polymer PC was much safer than high molecular weight PEI, and could condense plasmid DNA at an N/P ratio of 50 with suitable biophysical properties and a high transfection efficiency. Overexpression of ferritin enriched intracellular iron. The short-term iron imbalance initiated by AFP promoter regulation only occurred in hepatoma cells, resulting in signal contrast on MRI. The specific target TfR was also upregulated during this process. Conclusion: These results illustrate that the regulated ferritin gene carried by PC can be used as an endogenous contrast agent for MRI detection of hepatocellular carcinoma (HCC). This molecular imaging technique may promote safer early diagnosis of HCC, and provide a more highly specific target for future chemotherapy drugs.

Sialic acid-engineered mesoporous polydopamine dual loaded with ferritin gene and SPIO for achieving endogenous and exogenous synergistic T2-weighted magnetic resonance imaging of HCC

“…HepG2 cells transfected by SA-PEI/AFP-Fth with FAC exhibited a significant decrease of T2 signal intensity than that of absence of FAC (p < 0.01). The outcome was consisted with our previous study that the intracellular overexpressed ferritin in transfected cells could chelate with free iron in the presence of FAC, and further decrease the T2 relaxation time [ 33 ]. No significant difference was observed in control group after adding with FAC, as demonstrated by the similar signal intensity values.…”

“…Fth is also the major regulator of ferritin activity, which displays ferroxidase activity to promote iron oxidation and chelation, thus could be used as an T2 weighted image (T2WI) endogenous contrast agent [26][27][28][29][30][31][32]. Previous studies have evidenced that the transfection of Fth reporter gene with alpha-fetoprotein promoter (AFP-Fth) could induce a high expression level of ferritin only in the liver cancer cells, which therefore shows a potential ability in the diagnosis of HCC via MRI technique in vivo [33]. However, the utilization of upregulated ferritin as an endogenous contrast agent alone is still not satisfactory for precise HCC diagnosis.…”

<p>Dual-Effect of Magnetic Resonance Imaging Reporter Gene in Diagnosis and Treatment of Hepatocellular Carcinoma</p>

“…The cells were centrifugated once again and finally suspending in 10 µL PBS in EP tubes and filled with 1% un-solidified agarose solution in each tube. 21,41,42 T2*weighted imaging (T2*WI), T2WI, and T2 values were acquired using T2 fast spin-echo and ESWAN sequences by a 3.0-T MR (GE Discovery MR750, USA). FSE sequence: repetition time (TR) = 3070.0 ms, echo time (TE) = 96.6 ms, and slice thickness = 1.0 mm; ESWAN sequence: TR = 52.3 ms, TE = 6.5-30.2 ms, and slice thickness = 1.0 mm.…”

Enhanced transferrin modified targeting delivery system via AFP promoter MR imaging reporter gene transfection

“…12 h after transfection, FAC with concentrations of 0.5 mM was added to cultured medium of FAC (+) group and co-incubate with cells for 12 h and 36 h respectively. After thorough washing with PBS thrice to remove free iron, cells were fixed in 4% PFA for 10 min and dissociated with trypsin, followed by suspending in 10 ul PBS in EP tubes and filled with 30 ul 1% un-solidified agarose solution each tube [22,41]. T2*-weighted imaging (T2*WI), T2WI, T2 value and SI value were acquired using T2 fast spin echo and ESWAN sequences by a 3.0-T MR (GE Discovery MR750, USA).…”

“…Previously, the performance of AFP/Fth as an MRI reporter gene in AFP-positive cells was assessed [41], where indicated AFP/Fth appeared to be a promising endogenous contrast agent. In this paper, the influence of AFP/Fth on subsequent anti-tumor treatments while early molecular imaging was assessed.…”