Pretargeted dual-modality immuno-SPECT and near-infrared fluorescence imaging for image-guided surgery of prostate cancer

Cancer Res. 2014 Nov 1;74(21):6216-23. doi: 10.1158/0008-5472.CAN-14-0594. Epub 2014 Sep 24.


Radical removal of malignant lesions may be improved using tumor-targeted dual-modality probes that contain both a radiotracer and a fluorescent label to allow for enhanced intraoperative delineation of tumor resection margins. Because pretargeting strategies yield high signal-to-background ratios, we evaluated the feasibility of a pretargeting strategy for intraoperative imaging in prostate cancer using an anti-TROP-2 x anti-HSG bispecific antibody (TF12) in conjunction with the dual-labeled diHSG peptide (RDC018) equipped with both a DOTA chelate for radiolabeling purposes and a fluorophore (IRdye800CW) to allow near-infrared optical imaging. Nude mice implanted s.c. with TROP-2-expressing PC3 human prostate tumor cells or with PC3 metastases in the scapular and suprarenal region were injected i.v. with 1 mg of TF12 and, after 16 hours of tumor accumulation and blood clearance, were subsequently injected with 10 MBq, 0.2 nmol/mouse of either (111)In-RDC018 or (111)In-IMP288 as a control. Two hours after injection, both microSPECT/CT and fluorescence images were acquired, both before and after resection of the tumor nodules. After image acquisition, the biodistribution of (111)In-RDC018 and (111)In-IMP288 was determined and tumors were analyzed immunohistochemically. The biodistribution of the dual-label RDC018 showed specific accumulation in the TROP-2-expressing PC3 tumors (12.4 ± 3.7% ID/g at 2 hours postinjection), comparable with (111)In-IMP288 (9.1 ± 2.8% ID/g at 2 hours postinjection). MicroSPECT/CT and near-infrared fluorescence (NIRF) imaging confirmed this TROP-2-specific uptake of the dual-label (111)In-RDC018 in both the s.c. and metastatic growing tumor model. In addition, PC3 metastases could be visualized preoperatively with SPECT/CT and could subsequently be resected by image-guided surgery using intraoperative NIRF imaging, showing the preclinical feasibility of pretargeted dual-modality imaging approach in prostate cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Tumor / transplantation
  • Diagnostic Imaging
  • Fluorescence
  • Humans
  • Male
  • Mice
  • Mice, Nude
  • Neoplasm Metastasis / genetics
  • Neoplasm Metastasis / pathology
  • Positron-Emission Tomography
  • Prostatic Neoplasms / diagnostic imaging
  • Prostatic Neoplasms / pathology*
  • Prostatic Neoplasms / surgery*
  • Radiography
  • Spectroscopy, Near-Infrared
  • Surgery, Computer-Assisted*
  • Tomography, Emission-Computed, Single-Photon