A multimodal molecular imaging approach targeting urokinase plasminogen activator receptor for the diagnosis, resection and surveillance of urothelial cell carcinoma

Eur J Cancer. 2021 Mar:146:11-20. doi: 10.1016/j.ejca.2021.01.001. Epub 2021 Feb 6.

Abstract

With a 5-year recurrence rate of 30-78%, urothelial cell carcinoma (UCC) rates amongst the highest of all solid malignancies. Consequently, after transurethral resection, patients are subjugated to life-long endoscopic surveillance. A multimodal near-infrared (NIR) fluorescence-based imaging strategy can improve diagnosis, resection and surveillance, hence increasing quality of life.

Methods: Expression of urokinase plasminogen activator receptor (uPAR) and epithelial cell adhesion molecule (EpCAM) are determined on paraffin-embedded human UCC using immunohistochemistry and on UCC cell lines by flow cytometry. MNPR-101, a humanised monoclonal antibody targeting uPAR is conjugated to IRDye800CW and binding is validated in vitro using surface plasmon resonance and cell-based binding assays. In vivo NIR fluorescence and photoacoustic three-dimensional (3D) imaging are performed with subcutaneously growing human UM-UC-3luc2 cells in BALB/c-nude mice. The translational potential is confirmed in a metastasising UM-UC-3luc2 orthotopic mouse model. Infliximab-IRDye800CW and rituximab-IRDye800CW are used as controls.

Results: UCCs show prominent uPAR expression at the tumour-stroma interface and EpCAM on epithelial cells. uPAR and EpCAM are expressed by 6/7 and 4/7 UCC cell lines, respectively. In vitro, MNPR-101-IRDye800CW has a picomolar affinity for domain 2-3 of uPAR. In vivo fluorescence imaging with MNPR-101-IRDye800CW, specifically delineates both subcutaneous and orthotopic tumours with tumour-to-background ratios reaching as high as 6.8, differing significantly from controls (p < 0.0001). Photoacoustic 3D in depth imaging confirms the homogenous distribution of MNPR-101-IRDye800CW through the tumour.

Conclusions: MNPR-101-IRDye800CW is suitable for multimodal imaging of UCC, awaiting clinical translation.

Keywords: Bladder cancer; EpCAM; Image guided surgery; Photoacoustic imaging; Radical cystectomy; TUR surgery; Transurethral resection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / pharmacology*
  • Apoptosis
  • Cell Proliferation
  • Female
  • Humans
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Molecular Imaging / methods*
  • Optical Imaging / methods*
  • Prognosis
  • Receptors, Urokinase Plasminogen Activator / antagonists & inhibitors*
  • Receptors, Urokinase Plasminogen Activator / immunology
  • Receptors, Urokinase Plasminogen Activator / metabolism
  • Surgery, Computer-Assisted / methods*
  • Tumor Cells, Cultured
  • Urinary Bladder Neoplasms / diagnosis*
  • Urinary Bladder Neoplasms / immunology
  • Urinary Bladder Neoplasms / surgery
  • Xenograft Model Antitumor Assays

Substances

  • Antibodies, Monoclonal
  • PLAUR protein, human
  • Receptors, Urokinase Plasminogen Activator