Intraoperative navigation of glioblastoma based on IRDye800CW-targeted fluorescent probe / 中华核医学与分子影像杂志

ABSTRACT

Objective:To prepare a fluorescent probe Cetuximab-IRDye800CW targeting epidermal growth factor receptor (EGFR) and investigate its application value in surgical navigation of glioblastoma (GBM).Methods:The fluorescence properties of Cetuximab-IRDye800CW were determined by fluorescence spectrophotometer. The specificity of Cetuximab-IRDye800CW bound to GBM cells was verified by Western blot. The competitive binding method of enzyme-linked immunosorbent assay (ELISA) was used to prove whether the probe could achieve tumor targeting by binding to EGFR. Subcutaneous models of 6 nude mice of GBM were divided into experimental group ( n=3; injected with Cetuximab-IRDye800CW) and control group ( n=3; injected with IRDye800CW), and images were obtained at 5 min, 24 h, 48 h and 72 h after injection. Differences of mean fluorescence intensity (MFI) and tumor to background ratio (TBR) between experimental group and control group were compared. In situ models of GBM nude mice were established ( n=6), and MRI and intraoperative navigation were conducted, which were compared with pathological distribution. Independent-sample t test was used to analyze the data. Results:The maximum emission wavelength of Cetuximab-IRDye800CW was 820 nm, which could be received by near infrared fluorescence imaging equipment. Western blot showed that Cetuximab-IRDye800CW was only bound to GBM cells. The competitive binding of ELISA showed that Cetuximab-IRdye800CW could achieve tumor targeting by binding with EGFR. At 5 min, 24 h, 48 h and 72 h after injection of fluorescent materials, the MFI values of experimental group were 109.00±3.81, 73.36±9.93, 55.24±8.82, 37.71±6.11, which were higher than those of control group (91.32±4.17, 42.91±5.39, 25.08±6.05, 8.33±1.00; t values: 4.36-9.40, P values: 0.011-0.049). The TBR of experimental group was higher than that of control group at 24 h and 48 h after injection (24 h: 2.40±0.28 vs 1.57±0.07, t=4.94, P=0.039; 48 h: 2.07±0.12 vs 1.22±0.08, t=9.85, P=0.010). GBM in situ model was successfully constructed and verified by MRI, and the tumor was visualized under the fluorescence device navigation. Pathological distribution of the tumor with HE staining was consistent with fluorescence imaging. Conclusion:Cetuximab-IRDye800CW has fluorescence imaging capability and can identify tumor boundaries in intraoperative navigation of GBM, which has potential clinical application value.