Abstract:
Objective This work aimed to design epidermal growth factor receptor-targeted contrast agent C225-USPIO and to evaluate its magnetic resonance imaging (MRI) capability to mark the nasopharyngeal carcinoma xenograft in nude mice.
Methods C225-USPIO was designed by conjugating ultra-small superparamagnetic iron oxide (USPIO) nanoparticles with cetuximab (C225). The diameter of C225-USPIO was detected. Nasopharyngeal carcinoma cells SUNE1 5-8F with EGFR overexpression were transplanted into the ventral subcutaneous site of the right rear thigh of 12 nude mice. When the diameter of a transplanted tumor reached 5 mm, the nude mice were randomly divided into two groups, i.e., the experiment group (Group One) and the control group (Group Two), with 6 mice in each group.C225-USPIO and USPIO were separately injected into the mice through the caudal vein. MRI T2 weighted image (T2WI) scanning was conducted 0, 8, 24 and 72 h after the injection. The nano-contrast agent distribution in the tumor tissues was detected.
Results The diameter of the contrast agent ranged from 45 nm to 50 nm. MRI results showed that compared with the value of T2WI signal intensity 0 h after the contrast agent injection, the T2 value of the xenograft tumor in Group One was slightly decreased 8 h after the injection (P>0.05). The value was significantly decreased 24 h after the injection (P < 0.05), and no apparent change in the T2 value was observed 72 h after the injection(P>0.05). In Group Two, no significant changes in the T2 value of xenograft tumor after the USPIO injection were observed at each time point. No significant iron particles were found in the tumor tissue 72 h after the injection.
Conclusion C225-USPIO particles could pass through blood capillaries and could be applied for MR imaging in vivo. In addition, they can reduce MRI T2 signal intensity of the xenograftin nude mice with a certain specificity and targeting property.